jpayne@69: /* jpayne@69: * Copyright (c) Meta Platforms, Inc. and affiliates. jpayne@69: * All rights reserved. jpayne@69: * jpayne@69: * This source code is licensed under both the BSD-style license (found in the jpayne@69: * LICENSE file in the root directory of this source tree) and the GPLv2 (found jpayne@69: * in the COPYING file in the root directory of this source tree). jpayne@69: * You may select, at your option, one of the above-listed licenses. jpayne@69: */ jpayne@69: #if defined (__cplusplus) jpayne@69: extern "C" { jpayne@69: #endif jpayne@69: jpayne@69: #ifndef ZSTD_H_235446 jpayne@69: #define ZSTD_H_235446 jpayne@69: jpayne@69: /* ====== Dependencies ======*/ jpayne@69: #include /* INT_MAX */ jpayne@69: #include /* size_t */ jpayne@69: jpayne@69: jpayne@69: /* ===== ZSTDLIB_API : control library symbols visibility ===== */ jpayne@69: #ifndef ZSTDLIB_VISIBLE jpayne@69: /* Backwards compatibility with old macro name */ jpayne@69: # ifdef ZSTDLIB_VISIBILITY jpayne@69: # define ZSTDLIB_VISIBLE ZSTDLIB_VISIBILITY jpayne@69: # elif defined(__GNUC__) && (__GNUC__ >= 4) && !defined(__MINGW32__) jpayne@69: # define ZSTDLIB_VISIBLE __attribute__ ((visibility ("default"))) jpayne@69: # else jpayne@69: # define ZSTDLIB_VISIBLE jpayne@69: # endif jpayne@69: #endif jpayne@69: jpayne@69: #ifndef ZSTDLIB_HIDDEN jpayne@69: # if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(__MINGW32__) jpayne@69: # define ZSTDLIB_HIDDEN __attribute__ ((visibility ("hidden"))) jpayne@69: # else jpayne@69: # define ZSTDLIB_HIDDEN jpayne@69: # endif jpayne@69: #endif jpayne@69: jpayne@69: #if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) jpayne@69: # define ZSTDLIB_API __declspec(dllexport) ZSTDLIB_VISIBLE jpayne@69: #elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) jpayne@69: # define ZSTDLIB_API __declspec(dllimport) ZSTDLIB_VISIBLE /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/ jpayne@69: #else jpayne@69: # define ZSTDLIB_API ZSTDLIB_VISIBLE jpayne@69: #endif jpayne@69: jpayne@69: /* Deprecation warnings : jpayne@69: * Should these warnings be a problem, it is generally possible to disable them, jpayne@69: * typically with -Wno-deprecated-declarations for gcc or _CRT_SECURE_NO_WARNINGS in Visual. jpayne@69: * Otherwise, it's also possible to define ZSTD_DISABLE_DEPRECATE_WARNINGS. jpayne@69: */ jpayne@69: #ifdef ZSTD_DISABLE_DEPRECATE_WARNINGS jpayne@69: # define ZSTD_DEPRECATED(message) /* disable deprecation warnings */ jpayne@69: #else jpayne@69: # if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */ jpayne@69: # define ZSTD_DEPRECATED(message) [[deprecated(message)]] jpayne@69: # elif (defined(GNUC) && (GNUC > 4 || (GNUC == 4 && GNUC_MINOR >= 5))) || defined(__clang__) jpayne@69: # define ZSTD_DEPRECATED(message) __attribute__((deprecated(message))) jpayne@69: # elif defined(__GNUC__) && (__GNUC__ >= 3) jpayne@69: # define ZSTD_DEPRECATED(message) __attribute__((deprecated)) jpayne@69: # elif defined(_MSC_VER) jpayne@69: # define ZSTD_DEPRECATED(message) __declspec(deprecated(message)) jpayne@69: # else jpayne@69: # pragma message("WARNING: You need to implement ZSTD_DEPRECATED for this compiler") jpayne@69: # define ZSTD_DEPRECATED(message) jpayne@69: # endif jpayne@69: #endif /* ZSTD_DISABLE_DEPRECATE_WARNINGS */ jpayne@69: jpayne@69: jpayne@69: /******************************************************************************* jpayne@69: Introduction jpayne@69: jpayne@69: zstd, short for Zstandard, is a fast lossless compression algorithm, targeting jpayne@69: real-time compression scenarios at zlib-level and better compression ratios. jpayne@69: The zstd compression library provides in-memory compression and decompression jpayne@69: functions. jpayne@69: jpayne@69: The library supports regular compression levels from 1 up to ZSTD_maxCLevel(), jpayne@69: which is currently 22. Levels >= 20, labeled `--ultra`, should be used with jpayne@69: caution, as they require more memory. The library also offers negative jpayne@69: compression levels, which extend the range of speed vs. ratio preferences. jpayne@69: The lower the level, the faster the speed (at the cost of compression). jpayne@69: jpayne@69: Compression can be done in: jpayne@69: - a single step (described as Simple API) jpayne@69: - a single step, reusing a context (described as Explicit context) jpayne@69: - unbounded multiple steps (described as Streaming compression) jpayne@69: jpayne@69: The compression ratio achievable on small data can be highly improved using jpayne@69: a dictionary. Dictionary compression can be performed in: jpayne@69: - a single step (described as Simple dictionary API) jpayne@69: - a single step, reusing a dictionary (described as Bulk-processing jpayne@69: dictionary API) jpayne@69: jpayne@69: Advanced experimental functions can be accessed using jpayne@69: `#define ZSTD_STATIC_LINKING_ONLY` before including zstd.h. jpayne@69: jpayne@69: Advanced experimental APIs should never be used with a dynamically-linked jpayne@69: library. They are not "stable"; their definitions or signatures may change in jpayne@69: the future. Only static linking is allowed. jpayne@69: *******************************************************************************/ jpayne@69: jpayne@69: /*------ Version ------*/ jpayne@69: #define ZSTD_VERSION_MAJOR 1 jpayne@69: #define ZSTD_VERSION_MINOR 5 jpayne@69: #define ZSTD_VERSION_RELEASE 6 jpayne@69: #define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE) jpayne@69: jpayne@69: /*! ZSTD_versionNumber() : jpayne@69: * Return runtime library version, the value is (MAJOR*100*100 + MINOR*100 + RELEASE). */ jpayne@69: ZSTDLIB_API unsigned ZSTD_versionNumber(void); jpayne@69: jpayne@69: #define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE jpayne@69: #define ZSTD_QUOTE(str) #str jpayne@69: #define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str) jpayne@69: #define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION) jpayne@69: jpayne@69: /*! ZSTD_versionString() : jpayne@69: * Return runtime library version, like "1.4.5". Requires v1.3.0+. */ jpayne@69: ZSTDLIB_API const char* ZSTD_versionString(void); jpayne@69: jpayne@69: /* ************************************* jpayne@69: * Default constant jpayne@69: ***************************************/ jpayne@69: #ifndef ZSTD_CLEVEL_DEFAULT jpayne@69: # define ZSTD_CLEVEL_DEFAULT 3 jpayne@69: #endif jpayne@69: jpayne@69: /* ************************************* jpayne@69: * Constants jpayne@69: ***************************************/ jpayne@69: jpayne@69: /* All magic numbers are supposed read/written to/from files/memory using little-endian convention */ jpayne@69: #define ZSTD_MAGICNUMBER 0xFD2FB528 /* valid since v0.8.0 */ jpayne@69: #define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* valid since v0.7.0 */ jpayne@69: #define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50 /* all 16 values, from 0x184D2A50 to 0x184D2A5F, signal the beginning of a skippable frame */ jpayne@69: #define ZSTD_MAGIC_SKIPPABLE_MASK 0xFFFFFFF0 jpayne@69: jpayne@69: #define ZSTD_BLOCKSIZELOG_MAX 17 jpayne@69: #define ZSTD_BLOCKSIZE_MAX (1<= ZSTD_compressBound(srcSize)` guarantees that zstd will have jpayne@69: * enough space to successfully compress the data. jpayne@69: * @return : compressed size written into `dst` (<= `dstCapacity), jpayne@69: * or an error code if it fails (which can be tested using ZSTD_isError()). */ jpayne@69: ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: int compressionLevel); jpayne@69: jpayne@69: /*! ZSTD_decompress() : jpayne@69: * `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames. jpayne@69: * `dstCapacity` is an upper bound of originalSize to regenerate. jpayne@69: * If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data. jpayne@69: * @return : the number of bytes decompressed into `dst` (<= `dstCapacity`), jpayne@69: * or an errorCode if it fails (which can be tested using ZSTD_isError()). */ jpayne@69: ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t compressedSize); jpayne@69: jpayne@69: /*! ZSTD_getFrameContentSize() : requires v1.3.0+ jpayne@69: * `src` should point to the start of a ZSTD encoded frame. jpayne@69: * `srcSize` must be at least as large as the frame header. jpayne@69: * hint : any size >= `ZSTD_frameHeaderSize_max` is large enough. jpayne@69: * @return : - decompressed size of `src` frame content, if known jpayne@69: * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined jpayne@69: * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) jpayne@69: * note 1 : a 0 return value means the frame is valid but "empty". jpayne@69: * note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode. jpayne@69: * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. jpayne@69: * In which case, it's necessary to use streaming mode to decompress data. jpayne@69: * Optionally, application can rely on some implicit limit, jpayne@69: * as ZSTD_decompress() only needs an upper bound of decompressed size. jpayne@69: * (For example, data could be necessarily cut into blocks <= 16 KB). jpayne@69: * note 3 : decompressed size is always present when compression is completed using single-pass functions, jpayne@69: * such as ZSTD_compress(), ZSTD_compressCCtx() ZSTD_compress_usingDict() or ZSTD_compress_usingCDict(). jpayne@69: * note 4 : decompressed size can be very large (64-bits value), jpayne@69: * potentially larger than what local system can handle as a single memory segment. jpayne@69: * In which case, it's necessary to use streaming mode to decompress data. jpayne@69: * note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified. jpayne@69: * Always ensure return value fits within application's authorized limits. jpayne@69: * Each application can set its own limits. jpayne@69: * note 6 : This function replaces ZSTD_getDecompressedSize() */ jpayne@69: #define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1) jpayne@69: #define ZSTD_CONTENTSIZE_ERROR (0ULL - 2) jpayne@69: ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_getDecompressedSize() : jpayne@69: * NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize(). jpayne@69: * Both functions work the same way, but ZSTD_getDecompressedSize() blends jpayne@69: * "empty", "unknown" and "error" results to the same return value (0), jpayne@69: * while ZSTD_getFrameContentSize() gives them separate return values. jpayne@69: * @return : decompressed size of `src` frame content _if known and not empty_, 0 otherwise. */ jpayne@69: ZSTD_DEPRECATED("Replaced by ZSTD_getFrameContentSize") jpayne@69: ZSTDLIB_API jpayne@69: unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_findFrameCompressedSize() : Requires v1.4.0+ jpayne@69: * `src` should point to the start of a ZSTD frame or skippable frame. jpayne@69: * `srcSize` must be >= first frame size jpayne@69: * @return : the compressed size of the first frame starting at `src`, jpayne@69: * suitable to pass as `srcSize` to `ZSTD_decompress` or similar, jpayne@69: * or an error code if input is invalid */ jpayne@69: ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize); jpayne@69: jpayne@69: jpayne@69: /*====== Helper functions ======*/ jpayne@69: /* ZSTD_compressBound() : jpayne@69: * maximum compressed size in worst case single-pass scenario. jpayne@69: * When invoking `ZSTD_compress()` or any other one-pass compression function, jpayne@69: * it's recommended to provide @dstCapacity >= ZSTD_compressBound(srcSize) jpayne@69: * as it eliminates one potential failure scenario, jpayne@69: * aka not enough room in dst buffer to write the compressed frame. jpayne@69: * Note : ZSTD_compressBound() itself can fail, if @srcSize > ZSTD_MAX_INPUT_SIZE . jpayne@69: * In which case, ZSTD_compressBound() will return an error code jpayne@69: * which can be tested using ZSTD_isError(). jpayne@69: * jpayne@69: * ZSTD_COMPRESSBOUND() : jpayne@69: * same as ZSTD_compressBound(), but as a macro. jpayne@69: * It can be used to produce constants, which can be useful for static allocation, jpayne@69: * for example to size a static array on stack. jpayne@69: * Will produce constant value 0 if srcSize too large. jpayne@69: */ jpayne@69: #define ZSTD_MAX_INPUT_SIZE ((sizeof(size_t)==8) ? 0xFF00FF00FF00FF00ULL : 0xFF00FF00U) jpayne@69: #define ZSTD_COMPRESSBOUND(srcSize) (((size_t)(srcSize) >= ZSTD_MAX_INPUT_SIZE) ? 0 : (srcSize) + ((srcSize)>>8) + (((srcSize) < (128<<10)) ? (((128<<10) - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0)) /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */ jpayne@69: ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case single-pass scenario */ jpayne@69: /* ZSTD_isError() : jpayne@69: * Most ZSTD_* functions returning a size_t value can be tested for error, jpayne@69: * using ZSTD_isError(). jpayne@69: * @return 1 if error, 0 otherwise jpayne@69: */ jpayne@69: ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */ jpayne@69: ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */ jpayne@69: ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed, requires v1.4.0+ */ jpayne@69: ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */ jpayne@69: ZSTDLIB_API int ZSTD_defaultCLevel(void); /*!< default compression level, specified by ZSTD_CLEVEL_DEFAULT, requires v1.5.0+ */ jpayne@69: jpayne@69: jpayne@69: /*************************************** jpayne@69: * Explicit context jpayne@69: ***************************************/ jpayne@69: /*= Compression context jpayne@69: * When compressing many times, jpayne@69: * it is recommended to allocate a context just once, jpayne@69: * and reuse it for each successive compression operation. jpayne@69: * This will make workload friendlier for system's memory. jpayne@69: * Note : re-using context is just a speed / resource optimization. jpayne@69: * It doesn't change the compression ratio, which remains identical. jpayne@69: * Note 2 : In multi-threaded environments, jpayne@69: * use one different context per thread for parallel execution. jpayne@69: */ jpayne@69: typedef struct ZSTD_CCtx_s ZSTD_CCtx; jpayne@69: ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void); jpayne@69: ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); /* accept NULL pointer */ jpayne@69: jpayne@69: /*! ZSTD_compressCCtx() : jpayne@69: * Same as ZSTD_compress(), using an explicit ZSTD_CCtx. jpayne@69: * Important : in order to mirror `ZSTD_compress()` behavior, jpayne@69: * this function compresses at the requested compression level, jpayne@69: * __ignoring any other advanced parameter__ . jpayne@69: * If any advanced parameter was set using the advanced API, jpayne@69: * they will all be reset. Only `compressionLevel` remains. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* cctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: int compressionLevel); jpayne@69: jpayne@69: /*= Decompression context jpayne@69: * When decompressing many times, jpayne@69: * it is recommended to allocate a context only once, jpayne@69: * and reuse it for each successive compression operation. jpayne@69: * This will make workload friendlier for system's memory. jpayne@69: * Use one context per thread for parallel execution. */ jpayne@69: typedef struct ZSTD_DCtx_s ZSTD_DCtx; jpayne@69: ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void); jpayne@69: ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx); /* accept NULL pointer */ jpayne@69: jpayne@69: /*! ZSTD_decompressDCtx() : jpayne@69: * Same as ZSTD_decompress(), jpayne@69: * requires an allocated ZSTD_DCtx. jpayne@69: * Compatible with sticky parameters (see below). jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize); jpayne@69: jpayne@69: jpayne@69: /********************************************* jpayne@69: * Advanced compression API (Requires v1.4.0+) jpayne@69: **********************************************/ jpayne@69: jpayne@69: /* API design : jpayne@69: * Parameters are pushed one by one into an existing context, jpayne@69: * using ZSTD_CCtx_set*() functions. jpayne@69: * Pushed parameters are sticky : they are valid for next compressed frame, and any subsequent frame. jpayne@69: * "sticky" parameters are applicable to `ZSTD_compress2()` and `ZSTD_compressStream*()` ! jpayne@69: * __They do not apply to one-shot variants such as ZSTD_compressCCtx()__ . jpayne@69: * jpayne@69: * It's possible to reset all parameters to "default" using ZSTD_CCtx_reset(). jpayne@69: * jpayne@69: * This API supersedes all other "advanced" API entry points in the experimental section. jpayne@69: * In the future, we expect to remove API entry points from experimental which are redundant with this API. jpayne@69: */ jpayne@69: jpayne@69: jpayne@69: /* Compression strategies, listed from fastest to strongest */ jpayne@69: typedef enum { ZSTD_fast=1, jpayne@69: ZSTD_dfast=2, jpayne@69: ZSTD_greedy=3, jpayne@69: ZSTD_lazy=4, jpayne@69: ZSTD_lazy2=5, jpayne@69: ZSTD_btlazy2=6, jpayne@69: ZSTD_btopt=7, jpayne@69: ZSTD_btultra=8, jpayne@69: ZSTD_btultra2=9 jpayne@69: /* note : new strategies _might_ be added in the future. jpayne@69: Only the order (from fast to strong) is guaranteed */ jpayne@69: } ZSTD_strategy; jpayne@69: jpayne@69: typedef enum { jpayne@69: jpayne@69: /* compression parameters jpayne@69: * Note: When compressing with a ZSTD_CDict these parameters are superseded jpayne@69: * by the parameters used to construct the ZSTD_CDict. jpayne@69: * See ZSTD_CCtx_refCDict() for more info (superseded-by-cdict). */ jpayne@69: ZSTD_c_compressionLevel=100, /* Set compression parameters according to pre-defined cLevel table. jpayne@69: * Note that exact compression parameters are dynamically determined, jpayne@69: * depending on both compression level and srcSize (when known). jpayne@69: * Default level is ZSTD_CLEVEL_DEFAULT==3. jpayne@69: * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT. jpayne@69: * Note 1 : it's possible to pass a negative compression level. jpayne@69: * Note 2 : setting a level does not automatically set all other compression parameters jpayne@69: * to default. Setting this will however eventually dynamically impact the compression jpayne@69: * parameters which have not been manually set. The manually set jpayne@69: * ones will 'stick'. */ jpayne@69: /* Advanced compression parameters : jpayne@69: * It's possible to pin down compression parameters to some specific values. jpayne@69: * In which case, these values are no longer dynamically selected by the compressor */ jpayne@69: ZSTD_c_windowLog=101, /* Maximum allowed back-reference distance, expressed as power of 2. jpayne@69: * This will set a memory budget for streaming decompression, jpayne@69: * with larger values requiring more memory jpayne@69: * and typically compressing more. jpayne@69: * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX. jpayne@69: * Special: value 0 means "use default windowLog". jpayne@69: * Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT jpayne@69: * requires explicitly allowing such size at streaming decompression stage. */ jpayne@69: ZSTD_c_hashLog=102, /* Size of the initial probe table, as a power of 2. jpayne@69: * Resulting memory usage is (1 << (hashLog+2)). jpayne@69: * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX. jpayne@69: * Larger tables improve compression ratio of strategies <= dFast, jpayne@69: * and improve speed of strategies > dFast. jpayne@69: * Special: value 0 means "use default hashLog". */ jpayne@69: ZSTD_c_chainLog=103, /* Size of the multi-probe search table, as a power of 2. jpayne@69: * Resulting memory usage is (1 << (chainLog+2)). jpayne@69: * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX. jpayne@69: * Larger tables result in better and slower compression. jpayne@69: * This parameter is useless for "fast" strategy. jpayne@69: * It's still useful when using "dfast" strategy, jpayne@69: * in which case it defines a secondary probe table. jpayne@69: * Special: value 0 means "use default chainLog". */ jpayne@69: ZSTD_c_searchLog=104, /* Number of search attempts, as a power of 2. jpayne@69: * More attempts result in better and slower compression. jpayne@69: * This parameter is useless for "fast" and "dFast" strategies. jpayne@69: * Special: value 0 means "use default searchLog". */ jpayne@69: ZSTD_c_minMatch=105, /* Minimum size of searched matches. jpayne@69: * Note that Zstandard can still find matches of smaller size, jpayne@69: * it just tweaks its search algorithm to look for this size and larger. jpayne@69: * Larger values increase compression and decompression speed, but decrease ratio. jpayne@69: * Must be clamped between ZSTD_MINMATCH_MIN and ZSTD_MINMATCH_MAX. jpayne@69: * Note that currently, for all strategies < btopt, effective minimum is 4. jpayne@69: * , for all strategies > fast, effective maximum is 6. jpayne@69: * Special: value 0 means "use default minMatchLength". */ jpayne@69: ZSTD_c_targetLength=106, /* Impact of this field depends on strategy. jpayne@69: * For strategies btopt, btultra & btultra2: jpayne@69: * Length of Match considered "good enough" to stop search. jpayne@69: * Larger values make compression stronger, and slower. jpayne@69: * For strategy fast: jpayne@69: * Distance between match sampling. jpayne@69: * Larger values make compression faster, and weaker. jpayne@69: * Special: value 0 means "use default targetLength". */ jpayne@69: ZSTD_c_strategy=107, /* See ZSTD_strategy enum definition. jpayne@69: * The higher the value of selected strategy, the more complex it is, jpayne@69: * resulting in stronger and slower compression. jpayne@69: * Special: value 0 means "use default strategy". */ jpayne@69: jpayne@69: ZSTD_c_targetCBlockSize=130, /* v1.5.6+ jpayne@69: * Attempts to fit compressed block size into approximatively targetCBlockSize. jpayne@69: * Bound by ZSTD_TARGETCBLOCKSIZE_MIN and ZSTD_TARGETCBLOCKSIZE_MAX. jpayne@69: * Note that it's not a guarantee, just a convergence target (default:0). jpayne@69: * No target when targetCBlockSize == 0. jpayne@69: * This is helpful in low bandwidth streaming environments to improve end-to-end latency, jpayne@69: * when a client can make use of partial documents (a prominent example being Chrome). jpayne@69: * Note: this parameter is stable since v1.5.6. jpayne@69: * It was present as an experimental parameter in earlier versions, jpayne@69: * but it's not recommended using it with earlier library versions jpayne@69: * due to massive performance regressions. jpayne@69: */ jpayne@69: /* LDM mode parameters */ jpayne@69: ZSTD_c_enableLongDistanceMatching=160, /* Enable long distance matching. jpayne@69: * This parameter is designed to improve compression ratio jpayne@69: * for large inputs, by finding large matches at long distance. jpayne@69: * It increases memory usage and window size. jpayne@69: * Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB jpayne@69: * except when expressly set to a different value. jpayne@69: * Note: will be enabled by default if ZSTD_c_windowLog >= 128 MB and jpayne@69: * compression strategy >= ZSTD_btopt (== compression level 16+) */ jpayne@69: ZSTD_c_ldmHashLog=161, /* Size of the table for long distance matching, as a power of 2. jpayne@69: * Larger values increase memory usage and compression ratio, jpayne@69: * but decrease compression speed. jpayne@69: * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX jpayne@69: * default: windowlog - 7. jpayne@69: * Special: value 0 means "automatically determine hashlog". */ jpayne@69: ZSTD_c_ldmMinMatch=162, /* Minimum match size for long distance matcher. jpayne@69: * Larger/too small values usually decrease compression ratio. jpayne@69: * Must be clamped between ZSTD_LDM_MINMATCH_MIN and ZSTD_LDM_MINMATCH_MAX. jpayne@69: * Special: value 0 means "use default value" (default: 64). */ jpayne@69: ZSTD_c_ldmBucketSizeLog=163, /* Log size of each bucket in the LDM hash table for collision resolution. jpayne@69: * Larger values improve collision resolution but decrease compression speed. jpayne@69: * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX. jpayne@69: * Special: value 0 means "use default value" (default: 3). */ jpayne@69: ZSTD_c_ldmHashRateLog=164, /* Frequency of inserting/looking up entries into the LDM hash table. jpayne@69: * Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN). jpayne@69: * Default is MAX(0, (windowLog - ldmHashLog)), optimizing hash table usage. jpayne@69: * Larger values improve compression speed. jpayne@69: * Deviating far from default value will likely result in a compression ratio decrease. jpayne@69: * Special: value 0 means "automatically determine hashRateLog". */ jpayne@69: jpayne@69: /* frame parameters */ jpayne@69: ZSTD_c_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1) jpayne@69: * Content size must be known at the beginning of compression. jpayne@69: * This is automatically the case when using ZSTD_compress2(), jpayne@69: * For streaming scenarios, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */ jpayne@69: ZSTD_c_checksumFlag=201, /* A 32-bits checksum of content is written at end of frame (default:0) */ jpayne@69: ZSTD_c_dictIDFlag=202, /* When applicable, dictionary's ID is written into frame header (default:1) */ jpayne@69: jpayne@69: /* multi-threading parameters */ jpayne@69: /* These parameters are only active if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD). jpayne@69: * Otherwise, trying to set any other value than default (0) will be a no-op and return an error. jpayne@69: * In a situation where it's unknown if the linked library supports multi-threading or not, jpayne@69: * setting ZSTD_c_nbWorkers to any value >= 1 and consulting the return value provides a quick way to check this property. jpayne@69: */ jpayne@69: ZSTD_c_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel. jpayne@69: * When nbWorkers >= 1, triggers asynchronous mode when invoking ZSTD_compressStream*() : jpayne@69: * ZSTD_compressStream*() consumes input and flush output if possible, but immediately gives back control to caller, jpayne@69: * while compression is performed in parallel, within worker thread(s). jpayne@69: * (note : a strong exception to this rule is when first invocation of ZSTD_compressStream2() sets ZSTD_e_end : jpayne@69: * in which case, ZSTD_compressStream2() delegates to ZSTD_compress2(), which is always a blocking call). jpayne@69: * More workers improve speed, but also increase memory usage. jpayne@69: * Default value is `0`, aka "single-threaded mode" : no worker is spawned, jpayne@69: * compression is performed inside Caller's thread, and all invocations are blocking */ jpayne@69: ZSTD_c_jobSize=401, /* Size of a compression job. This value is enforced only when nbWorkers >= 1. jpayne@69: * Each compression job is completed in parallel, so this value can indirectly impact the nb of active threads. jpayne@69: * 0 means default, which is dynamically determined based on compression parameters. jpayne@69: * Job size must be a minimum of overlap size, or ZSTDMT_JOBSIZE_MIN (= 512 KB), whichever is largest. jpayne@69: * The minimum size is automatically and transparently enforced. */ jpayne@69: ZSTD_c_overlapLog=402, /* Control the overlap size, as a fraction of window size. jpayne@69: * The overlap size is an amount of data reloaded from previous job at the beginning of a new job. jpayne@69: * It helps preserve compression ratio, while each job is compressed in parallel. jpayne@69: * This value is enforced only when nbWorkers >= 1. jpayne@69: * Larger values increase compression ratio, but decrease speed. jpayne@69: * Possible values range from 0 to 9 : jpayne@69: * - 0 means "default" : value will be determined by the library, depending on strategy jpayne@69: * - 1 means "no overlap" jpayne@69: * - 9 means "full overlap", using a full window size. jpayne@69: * Each intermediate rank increases/decreases load size by a factor 2 : jpayne@69: * 9: full window; 8: w/2; 7: w/4; 6: w/8; 5:w/16; 4: w/32; 3:w/64; 2:w/128; 1:no overlap; 0:default jpayne@69: * default value varies between 6 and 9, depending on strategy */ jpayne@69: jpayne@69: /* note : additional experimental parameters are also available jpayne@69: * within the experimental section of the API. jpayne@69: * At the time of this writing, they include : jpayne@69: * ZSTD_c_rsyncable jpayne@69: * ZSTD_c_format jpayne@69: * ZSTD_c_forceMaxWindow jpayne@69: * ZSTD_c_forceAttachDict jpayne@69: * ZSTD_c_literalCompressionMode jpayne@69: * ZSTD_c_srcSizeHint jpayne@69: * ZSTD_c_enableDedicatedDictSearch jpayne@69: * ZSTD_c_stableInBuffer jpayne@69: * ZSTD_c_stableOutBuffer jpayne@69: * ZSTD_c_blockDelimiters jpayne@69: * ZSTD_c_validateSequences jpayne@69: * ZSTD_c_useBlockSplitter jpayne@69: * ZSTD_c_useRowMatchFinder jpayne@69: * ZSTD_c_prefetchCDictTables jpayne@69: * ZSTD_c_enableSeqProducerFallback jpayne@69: * ZSTD_c_maxBlockSize jpayne@69: * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. jpayne@69: * note : never ever use experimentalParam? names directly; jpayne@69: * also, the enums values themselves are unstable and can still change. jpayne@69: */ jpayne@69: ZSTD_c_experimentalParam1=500, jpayne@69: ZSTD_c_experimentalParam2=10, jpayne@69: ZSTD_c_experimentalParam3=1000, jpayne@69: ZSTD_c_experimentalParam4=1001, jpayne@69: ZSTD_c_experimentalParam5=1002, jpayne@69: /* was ZSTD_c_experimentalParam6=1003; is now ZSTD_c_targetCBlockSize */ jpayne@69: ZSTD_c_experimentalParam7=1004, jpayne@69: ZSTD_c_experimentalParam8=1005, jpayne@69: ZSTD_c_experimentalParam9=1006, jpayne@69: ZSTD_c_experimentalParam10=1007, jpayne@69: ZSTD_c_experimentalParam11=1008, jpayne@69: ZSTD_c_experimentalParam12=1009, jpayne@69: ZSTD_c_experimentalParam13=1010, jpayne@69: ZSTD_c_experimentalParam14=1011, jpayne@69: ZSTD_c_experimentalParam15=1012, jpayne@69: ZSTD_c_experimentalParam16=1013, jpayne@69: ZSTD_c_experimentalParam17=1014, jpayne@69: ZSTD_c_experimentalParam18=1015, jpayne@69: ZSTD_c_experimentalParam19=1016 jpayne@69: } ZSTD_cParameter; jpayne@69: jpayne@69: typedef struct { jpayne@69: size_t error; jpayne@69: int lowerBound; jpayne@69: int upperBound; jpayne@69: } ZSTD_bounds; jpayne@69: jpayne@69: /*! ZSTD_cParam_getBounds() : jpayne@69: * All parameters must belong to an interval with lower and upper bounds, jpayne@69: * otherwise they will either trigger an error or be automatically clamped. jpayne@69: * @return : a structure, ZSTD_bounds, which contains jpayne@69: * - an error status field, which must be tested using ZSTD_isError() jpayne@69: * - lower and upper bounds, both inclusive jpayne@69: */ jpayne@69: ZSTDLIB_API ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter cParam); jpayne@69: jpayne@69: /*! ZSTD_CCtx_setParameter() : jpayne@69: * Set one compression parameter, selected by enum ZSTD_cParameter. jpayne@69: * All parameters have valid bounds. Bounds can be queried using ZSTD_cParam_getBounds(). jpayne@69: * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). jpayne@69: * Setting a parameter is generally only possible during frame initialization (before starting compression). jpayne@69: * Exception : when using multi-threading mode (nbWorkers >= 1), jpayne@69: * the following parameters can be updated _during_ compression (within same frame): jpayne@69: * => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy. jpayne@69: * new parameters will be active for next job only (after a flush()). jpayne@69: * @return : an error code (which can be tested using ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value); jpayne@69: jpayne@69: /*! ZSTD_CCtx_setPledgedSrcSize() : jpayne@69: * Total input data size to be compressed as a single frame. jpayne@69: * Value will be written in frame header, unless if explicitly forbidden using ZSTD_c_contentSizeFlag. jpayne@69: * This value will also be controlled at end of frame, and trigger an error if not respected. jpayne@69: * @result : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: * Note 1 : pledgedSrcSize==0 actually means zero, aka an empty frame. jpayne@69: * In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN. jpayne@69: * ZSTD_CONTENTSIZE_UNKNOWN is default value for any new frame. jpayne@69: * Note 2 : pledgedSrcSize is only valid once, for the next frame. jpayne@69: * It's discarded at the end of the frame, and replaced by ZSTD_CONTENTSIZE_UNKNOWN. jpayne@69: * Note 3 : Whenever all input data is provided and consumed in a single round, jpayne@69: * for example with ZSTD_compress2(), jpayne@69: * or invoking immediately ZSTD_compressStream2(,,,ZSTD_e_end), jpayne@69: * this value is automatically overridden by srcSize instead. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize); jpayne@69: jpayne@69: typedef enum { jpayne@69: ZSTD_reset_session_only = 1, jpayne@69: ZSTD_reset_parameters = 2, jpayne@69: ZSTD_reset_session_and_parameters = 3 jpayne@69: } ZSTD_ResetDirective; jpayne@69: jpayne@69: /*! ZSTD_CCtx_reset() : jpayne@69: * There are 2 different things that can be reset, independently or jointly : jpayne@69: * - The session : will stop compressing current frame, and make CCtx ready to start a new one. jpayne@69: * Useful after an error, or to interrupt any ongoing compression. jpayne@69: * Any internal data not yet flushed is cancelled. jpayne@69: * Compression parameters and dictionary remain unchanged. jpayne@69: * They will be used to compress next frame. jpayne@69: * Resetting session never fails. jpayne@69: * - The parameters : changes all parameters back to "default". jpayne@69: * This also removes any reference to any dictionary or external sequence producer. jpayne@69: * Parameters can only be changed between 2 sessions (i.e. no compression is currently ongoing) jpayne@69: * otherwise the reset fails, and function returns an error value (which can be tested using ZSTD_isError()) jpayne@69: * - Both : similar to resetting the session, followed by resetting parameters. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset); jpayne@69: jpayne@69: /*! ZSTD_compress2() : jpayne@69: * Behave the same as ZSTD_compressCCtx(), but compression parameters are set using the advanced API. jpayne@69: * (note that this entry point doesn't even expose a compression level parameter). jpayne@69: * ZSTD_compress2() always starts a new frame. jpayne@69: * Should cctx hold data from a previously unfinished frame, everything about it is forgotten. jpayne@69: * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() jpayne@69: * - The function is always blocking, returns when compression is completed. jpayne@69: * NOTE: Providing `dstCapacity >= ZSTD_compressBound(srcSize)` guarantees that zstd will have jpayne@69: * enough space to successfully compress the data, though it is possible it fails for other reasons. jpayne@69: * @return : compressed size written into `dst` (<= `dstCapacity), jpayne@69: * or an error code if it fails (which can be tested using ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_compress2( ZSTD_CCtx* cctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize); jpayne@69: jpayne@69: jpayne@69: /*********************************************** jpayne@69: * Advanced decompression API (Requires v1.4.0+) jpayne@69: ************************************************/ jpayne@69: jpayne@69: /* The advanced API pushes parameters one by one into an existing DCtx context. jpayne@69: * Parameters are sticky, and remain valid for all following frames jpayne@69: * using the same DCtx context. jpayne@69: * It's possible to reset parameters to default values using ZSTD_DCtx_reset(). jpayne@69: * Note : This API is compatible with existing ZSTD_decompressDCtx() and ZSTD_decompressStream(). jpayne@69: * Therefore, no new decompression function is necessary. jpayne@69: */ jpayne@69: jpayne@69: typedef enum { jpayne@69: jpayne@69: ZSTD_d_windowLogMax=100, /* Select a size limit (in power of 2) beyond which jpayne@69: * the streaming API will refuse to allocate memory buffer jpayne@69: * in order to protect the host from unreasonable memory requirements. jpayne@69: * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. jpayne@69: * By default, a decompression context accepts window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT). jpayne@69: * Special: value 0 means "use default maximum windowLog". */ jpayne@69: jpayne@69: /* note : additional experimental parameters are also available jpayne@69: * within the experimental section of the API. jpayne@69: * At the time of this writing, they include : jpayne@69: * ZSTD_d_format jpayne@69: * ZSTD_d_stableOutBuffer jpayne@69: * ZSTD_d_forceIgnoreChecksum jpayne@69: * ZSTD_d_refMultipleDDicts jpayne@69: * ZSTD_d_disableHuffmanAssembly jpayne@69: * ZSTD_d_maxBlockSize jpayne@69: * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. jpayne@69: * note : never ever use experimentalParam? names directly jpayne@69: */ jpayne@69: ZSTD_d_experimentalParam1=1000, jpayne@69: ZSTD_d_experimentalParam2=1001, jpayne@69: ZSTD_d_experimentalParam3=1002, jpayne@69: ZSTD_d_experimentalParam4=1003, jpayne@69: ZSTD_d_experimentalParam5=1004, jpayne@69: ZSTD_d_experimentalParam6=1005 jpayne@69: jpayne@69: } ZSTD_dParameter; jpayne@69: jpayne@69: /*! ZSTD_dParam_getBounds() : jpayne@69: * All parameters must belong to an interval with lower and upper bounds, jpayne@69: * otherwise they will either trigger an error or be automatically clamped. jpayne@69: * @return : a structure, ZSTD_bounds, which contains jpayne@69: * - an error status field, which must be tested using ZSTD_isError() jpayne@69: * - both lower and upper bounds, inclusive jpayne@69: */ jpayne@69: ZSTDLIB_API ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam); jpayne@69: jpayne@69: /*! ZSTD_DCtx_setParameter() : jpayne@69: * Set one compression parameter, selected by enum ZSTD_dParameter. jpayne@69: * All parameters have valid bounds. Bounds can be queried using ZSTD_dParam_getBounds(). jpayne@69: * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). jpayne@69: * Setting a parameter is only possible during frame initialization (before starting decompression). jpayne@69: * @return : 0, or an error code (which can be tested using ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int value); jpayne@69: jpayne@69: /*! ZSTD_DCtx_reset() : jpayne@69: * Return a DCtx to clean state. jpayne@69: * Session and parameters can be reset jointly or separately. jpayne@69: * Parameters can only be reset when no active frame is being decompressed. jpayne@69: * @return : 0, or an error code, which can be tested with ZSTD_isError() jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset); jpayne@69: jpayne@69: jpayne@69: /**************************** jpayne@69: * Streaming jpayne@69: ****************************/ jpayne@69: jpayne@69: typedef struct ZSTD_inBuffer_s { jpayne@69: const void* src; /**< start of input buffer */ jpayne@69: size_t size; /**< size of input buffer */ jpayne@69: size_t pos; /**< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */ jpayne@69: } ZSTD_inBuffer; jpayne@69: jpayne@69: typedef struct ZSTD_outBuffer_s { jpayne@69: void* dst; /**< start of output buffer */ jpayne@69: size_t size; /**< size of output buffer */ jpayne@69: size_t pos; /**< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */ jpayne@69: } ZSTD_outBuffer; jpayne@69: jpayne@69: jpayne@69: jpayne@69: /*-*********************************************************************** jpayne@69: * Streaming compression - HowTo jpayne@69: * jpayne@69: * A ZSTD_CStream object is required to track streaming operation. jpayne@69: * Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources. jpayne@69: * ZSTD_CStream objects can be reused multiple times on consecutive compression operations. jpayne@69: * It is recommended to reuse ZSTD_CStream since it will play nicer with system's memory, by re-using already allocated memory. jpayne@69: * jpayne@69: * For parallel execution, use one separate ZSTD_CStream per thread. jpayne@69: * jpayne@69: * note : since v1.3.0, ZSTD_CStream and ZSTD_CCtx are the same thing. jpayne@69: * jpayne@69: * Parameters are sticky : when starting a new compression on the same context, jpayne@69: * it will reuse the same sticky parameters as previous compression session. jpayne@69: * When in doubt, it's recommended to fully initialize the context before usage. jpayne@69: * Use ZSTD_CCtx_reset() to reset the context and ZSTD_CCtx_setParameter(), jpayne@69: * ZSTD_CCtx_setPledgedSrcSize(), or ZSTD_CCtx_loadDictionary() and friends to jpayne@69: * set more specific parameters, the pledged source size, or load a dictionary. jpayne@69: * jpayne@69: * Use ZSTD_compressStream2() with ZSTD_e_continue as many times as necessary to jpayne@69: * consume input stream. The function will automatically update both `pos` jpayne@69: * fields within `input` and `output`. jpayne@69: * Note that the function may not consume the entire input, for example, because jpayne@69: * the output buffer is already full, in which case `input.pos < input.size`. jpayne@69: * The caller must check if input has been entirely consumed. jpayne@69: * If not, the caller must make some room to receive more compressed data, jpayne@69: * and then present again remaining input data. jpayne@69: * note: ZSTD_e_continue is guaranteed to make some forward progress when called, jpayne@69: * but doesn't guarantee maximal forward progress. This is especially relevant jpayne@69: * when compressing with multiple threads. The call won't block if it can jpayne@69: * consume some input, but if it can't it will wait for some, but not all, jpayne@69: * output to be flushed. jpayne@69: * @return : provides a minimum amount of data remaining to be flushed from internal buffers jpayne@69: * or an error code, which can be tested using ZSTD_isError(). jpayne@69: * jpayne@69: * At any moment, it's possible to flush whatever data might remain stuck within internal buffer, jpayne@69: * using ZSTD_compressStream2() with ZSTD_e_flush. `output->pos` will be updated. jpayne@69: * Note that, if `output->size` is too small, a single invocation with ZSTD_e_flush might not be enough (return code > 0). jpayne@69: * In which case, make some room to receive more compressed data, and call again ZSTD_compressStream2() with ZSTD_e_flush. jpayne@69: * You must continue calling ZSTD_compressStream2() with ZSTD_e_flush until it returns 0, at which point you can change the jpayne@69: * operation. jpayne@69: * note: ZSTD_e_flush will flush as much output as possible, meaning when compressing with multiple threads, it will jpayne@69: * block until the flush is complete or the output buffer is full. jpayne@69: * @return : 0 if internal buffers are entirely flushed, jpayne@69: * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), jpayne@69: * or an error code, which can be tested using ZSTD_isError(). jpayne@69: * jpayne@69: * Calling ZSTD_compressStream2() with ZSTD_e_end instructs to finish a frame. jpayne@69: * It will perform a flush and write frame epilogue. jpayne@69: * The epilogue is required for decoders to consider a frame completed. jpayne@69: * flush operation is the same, and follows same rules as calling ZSTD_compressStream2() with ZSTD_e_flush. jpayne@69: * You must continue calling ZSTD_compressStream2() with ZSTD_e_end until it returns 0, at which point you are free to jpayne@69: * start a new frame. jpayne@69: * note: ZSTD_e_end will flush as much output as possible, meaning when compressing with multiple threads, it will jpayne@69: * block until the flush is complete or the output buffer is full. jpayne@69: * @return : 0 if frame fully completed and fully flushed, jpayne@69: * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), jpayne@69: * or an error code, which can be tested using ZSTD_isError(). jpayne@69: * jpayne@69: * *******************************************************************/ jpayne@69: jpayne@69: typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are now effectively same object (>= v1.3.0) */ jpayne@69: /* Continue to distinguish them for compatibility with older versions <= v1.2.0 */ jpayne@69: /*===== ZSTD_CStream management functions =====*/ jpayne@69: ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void); jpayne@69: ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs); /* accept NULL pointer */ jpayne@69: jpayne@69: /*===== Streaming compression functions =====*/ jpayne@69: typedef enum { jpayne@69: ZSTD_e_continue=0, /* collect more data, encoder decides when to output compressed result, for optimal compression ratio */ jpayne@69: ZSTD_e_flush=1, /* flush any data provided so far, jpayne@69: * it creates (at least) one new block, that can be decoded immediately on reception; jpayne@69: * frame will continue: any future data can still reference previously compressed data, improving compression. jpayne@69: * note : multithreaded compression will block to flush as much output as possible. */ jpayne@69: ZSTD_e_end=2 /* flush any remaining data _and_ close current frame. jpayne@69: * note that frame is only closed after compressed data is fully flushed (return value == 0). jpayne@69: * After that point, any additional data starts a new frame. jpayne@69: * note : each frame is independent (does not reference any content from previous frame). jpayne@69: : note : multithreaded compression will block to flush as much output as possible. */ jpayne@69: } ZSTD_EndDirective; jpayne@69: jpayne@69: /*! ZSTD_compressStream2() : Requires v1.4.0+ jpayne@69: * Behaves about the same as ZSTD_compressStream, with additional control on end directive. jpayne@69: * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() jpayne@69: * - Compression parameters cannot be changed once compression is started (save a list of exceptions in multi-threading mode) jpayne@69: * - output->pos must be <= dstCapacity, input->pos must be <= srcSize jpayne@69: * - output->pos and input->pos will be updated. They are guaranteed to remain below their respective limit. jpayne@69: * - endOp must be a valid directive jpayne@69: * - When nbWorkers==0 (default), function is blocking : it completes its job before returning to caller. jpayne@69: * - When nbWorkers>=1, function is non-blocking : it copies a portion of input, distributes jobs to internal worker threads, flush to output whatever is available, jpayne@69: * and then immediately returns, just indicating that there is some data remaining to be flushed. jpayne@69: * The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte. jpayne@69: * - Exception : if the first call requests a ZSTD_e_end directive and provides enough dstCapacity, the function delegates to ZSTD_compress2() which is always blocking. jpayne@69: * - @return provides a minimum amount of data remaining to be flushed from internal buffers jpayne@69: * or an error code, which can be tested using ZSTD_isError(). jpayne@69: * if @return != 0, flush is not fully completed, there is still some data left within internal buffers. jpayne@69: * This is useful for ZSTD_e_flush, since in this case more flushes are necessary to empty all buffers. jpayne@69: * For ZSTD_e_end, @return == 0 when internal buffers are fully flushed and frame is completed. jpayne@69: * - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0), jpayne@69: * only ZSTD_e_end or ZSTD_e_flush operations are allowed. jpayne@69: * Before starting a new compression job, or changing compression parameters, jpayne@69: * it is required to fully flush internal buffers. jpayne@69: * - note: if an operation ends with an error, it may leave @cctx in an undefined state. jpayne@69: * Therefore, it's UB to invoke ZSTD_compressStream2() of ZSTD_compressStream() on such a state. jpayne@69: * In order to be re-employed after an error, a state must be reset, jpayne@69: * which can be done explicitly (ZSTD_CCtx_reset()), jpayne@69: * or is sometimes implied by methods starting a new compression job (ZSTD_initCStream(), ZSTD_compressCCtx()) jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_compressStream2( ZSTD_CCtx* cctx, jpayne@69: ZSTD_outBuffer* output, jpayne@69: ZSTD_inBuffer* input, jpayne@69: ZSTD_EndDirective endOp); jpayne@69: jpayne@69: jpayne@69: /* These buffer sizes are softly recommended. jpayne@69: * They are not required : ZSTD_compressStream*() happily accepts any buffer size, for both input and output. jpayne@69: * Respecting the recommended size just makes it a bit easier for ZSTD_compressStream*(), jpayne@69: * reducing the amount of memory shuffling and buffering, resulting in minor performance savings. jpayne@69: * jpayne@69: * However, note that these recommendations are from the perspective of a C caller program. jpayne@69: * If the streaming interface is invoked from some other language, jpayne@69: * especially managed ones such as Java or Go, through a foreign function interface such as jni or cgo, jpayne@69: * a major performance rule is to reduce crossing such interface to an absolute minimum. jpayne@69: * It's not rare that performance ends being spent more into the interface, rather than compression itself. jpayne@69: * In which cases, prefer using large buffers, as large as practical, jpayne@69: * for both input and output, to reduce the nb of roundtrips. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /**< recommended size for input buffer */ jpayne@69: ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block. */ jpayne@69: jpayne@69: jpayne@69: /* ***************************************************************************** jpayne@69: * This following is a legacy streaming API, available since v1.0+ . jpayne@69: * It can be replaced by ZSTD_CCtx_reset() and ZSTD_compressStream2(). jpayne@69: * It is redundant, but remains fully supported. jpayne@69: ******************************************************************************/ jpayne@69: jpayne@69: /*! jpayne@69: * Equivalent to: jpayne@69: * jpayne@69: * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); jpayne@69: * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) jpayne@69: * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); jpayne@69: * jpayne@69: * Note that ZSTD_initCStream() clears any previously set dictionary. Use the new API jpayne@69: * to compress with a dictionary. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel); jpayne@69: /*! jpayne@69: * Alternative for ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue). jpayne@69: * NOTE: The return value is different. ZSTD_compressStream() returns a hint for jpayne@69: * the next read size (if non-zero and not an error). ZSTD_compressStream2() jpayne@69: * returns the minimum nb of bytes left to flush (if non-zero and not an error). jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input); jpayne@69: /*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_flush). */ jpayne@69: ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); jpayne@69: /*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_end). */ jpayne@69: ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); jpayne@69: jpayne@69: jpayne@69: /*-*************************************************************************** jpayne@69: * Streaming decompression - HowTo jpayne@69: * jpayne@69: * A ZSTD_DStream object is required to track streaming operations. jpayne@69: * Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources. jpayne@69: * ZSTD_DStream objects can be reused multiple times. jpayne@69: * jpayne@69: * Use ZSTD_initDStream() to start a new decompression operation. jpayne@69: * @return : recommended first input size jpayne@69: * Alternatively, use advanced API to set specific properties. jpayne@69: * jpayne@69: * Use ZSTD_decompressStream() repetitively to consume your input. jpayne@69: * The function will update both `pos` fields. jpayne@69: * If `input.pos < input.size`, some input has not been consumed. jpayne@69: * It's up to the caller to present again remaining data. jpayne@69: * The function tries to flush all data decoded immediately, respecting output buffer size. jpayne@69: * If `output.pos < output.size`, decoder has flushed everything it could. jpayne@69: * But if `output.pos == output.size`, there might be some data left within internal buffers., jpayne@69: * In which case, call ZSTD_decompressStream() again to flush whatever remains in the buffer. jpayne@69: * Note : with no additional input provided, amount of data flushed is necessarily <= ZSTD_BLOCKSIZE_MAX. jpayne@69: * @return : 0 when a frame is completely decoded and fully flushed, jpayne@69: * or an error code, which can be tested using ZSTD_isError(), jpayne@69: * or any other value > 0, which means there is still some decoding or flushing to do to complete current frame : jpayne@69: * the return value is a suggested next input size (just a hint for better latency) jpayne@69: * that will never request more than the remaining frame size. jpayne@69: * *******************************************************************************/ jpayne@69: jpayne@69: typedef ZSTD_DCtx ZSTD_DStream; /**< DCtx and DStream are now effectively same object (>= v1.3.0) */ jpayne@69: /* For compatibility with versions <= v1.2.0, prefer differentiating them. */ jpayne@69: /*===== ZSTD_DStream management functions =====*/ jpayne@69: ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void); jpayne@69: ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds); /* accept NULL pointer */ jpayne@69: jpayne@69: /*===== Streaming decompression functions =====*/ jpayne@69: jpayne@69: /*! ZSTD_initDStream() : jpayne@69: * Initialize/reset DStream state for new decompression operation. jpayne@69: * Call before new decompression operation using same DStream. jpayne@69: * jpayne@69: * Note : This function is redundant with the advanced API and equivalent to: jpayne@69: * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); jpayne@69: * ZSTD_DCtx_refDDict(zds, NULL); jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds); jpayne@69: jpayne@69: /*! ZSTD_decompressStream() : jpayne@69: * Streaming decompression function. jpayne@69: * Call repetitively to consume full input updating it as necessary. jpayne@69: * Function will update both input and output `pos` fields exposing current state via these fields: jpayne@69: * - `input.pos < input.size`, some input remaining and caller should provide remaining input jpayne@69: * on the next call. jpayne@69: * - `output.pos < output.size`, decoder finished and flushed all remaining buffers. jpayne@69: * - `output.pos == output.size`, potentially uncflushed data present in the internal buffers, jpayne@69: * call ZSTD_decompressStream() again to flush remaining data to output. jpayne@69: * Note : with no additional input, amount of data flushed <= ZSTD_BLOCKSIZE_MAX. jpayne@69: * jpayne@69: * @return : 0 when a frame is completely decoded and fully flushed, jpayne@69: * or an error code, which can be tested using ZSTD_isError(), jpayne@69: * or any other value > 0, which means there is some decoding or flushing to do to complete current frame. jpayne@69: * jpayne@69: * Note: when an operation returns with an error code, the @zds state may be left in undefined state. jpayne@69: * It's UB to invoke `ZSTD_decompressStream()` on such a state. jpayne@69: * In order to re-use such a state, it must be first reset, jpayne@69: * which can be done explicitly (`ZSTD_DCtx_reset()`), jpayne@69: * or is implied for operations starting some new decompression job (`ZSTD_initDStream`, `ZSTD_decompressDCtx()`, `ZSTD_decompress_usingDict()`) jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input); jpayne@69: jpayne@69: ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */ jpayne@69: ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */ jpayne@69: jpayne@69: jpayne@69: /************************** jpayne@69: * Simple dictionary API jpayne@69: ***************************/ jpayne@69: /*! ZSTD_compress_usingDict() : jpayne@69: * Compression at an explicit compression level using a Dictionary. jpayne@69: * A dictionary can be any arbitrary data segment (also called a prefix), jpayne@69: * or a buffer with specified information (see zdict.h). jpayne@69: * Note : This function loads the dictionary, resulting in significant startup delay. jpayne@69: * It's intended for a dictionary used only once. jpayne@69: * Note 2 : When `dict == NULL || dictSize < 8` no dictionary is used. */ jpayne@69: ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: const void* dict,size_t dictSize, jpayne@69: int compressionLevel); jpayne@69: jpayne@69: /*! ZSTD_decompress_usingDict() : jpayne@69: * Decompression using a known Dictionary. jpayne@69: * Dictionary must be identical to the one used during compression. jpayne@69: * Note : This function loads the dictionary, resulting in significant startup delay. jpayne@69: * It's intended for a dictionary used only once. jpayne@69: * Note : When `dict == NULL || dictSize < 8` no dictionary is used. */ jpayne@69: ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: const void* dict,size_t dictSize); jpayne@69: jpayne@69: jpayne@69: /*********************************** jpayne@69: * Bulk processing dictionary API jpayne@69: **********************************/ jpayne@69: typedef struct ZSTD_CDict_s ZSTD_CDict; jpayne@69: jpayne@69: /*! ZSTD_createCDict() : jpayne@69: * When compressing multiple messages or blocks using the same dictionary, jpayne@69: * it's recommended to digest the dictionary only once, since it's a costly operation. jpayne@69: * ZSTD_createCDict() will create a state from digesting a dictionary. jpayne@69: * The resulting state can be used for future compression operations with very limited startup cost. jpayne@69: * ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only. jpayne@69: * @dictBuffer can be released after ZSTD_CDict creation, because its content is copied within CDict. jpayne@69: * Note 1 : Consider experimental function `ZSTD_createCDict_byReference()` if you prefer to not duplicate @dictBuffer content. jpayne@69: * Note 2 : A ZSTD_CDict can be created from an empty @dictBuffer, jpayne@69: * in which case the only thing that it transports is the @compressionLevel. jpayne@69: * This can be useful in a pipeline featuring ZSTD_compress_usingCDict() exclusively, jpayne@69: * expecting a ZSTD_CDict parameter with any data, including those without a known dictionary. */ jpayne@69: ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, jpayne@69: int compressionLevel); jpayne@69: jpayne@69: /*! ZSTD_freeCDict() : jpayne@69: * Function frees memory allocated by ZSTD_createCDict(). jpayne@69: * If a NULL pointer is passed, no operation is performed. */ jpayne@69: ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict); jpayne@69: jpayne@69: /*! ZSTD_compress_usingCDict() : jpayne@69: * Compression using a digested Dictionary. jpayne@69: * Recommended when same dictionary is used multiple times. jpayne@69: * Note : compression level is _decided at dictionary creation time_, jpayne@69: * and frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) */ jpayne@69: ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: const ZSTD_CDict* cdict); jpayne@69: jpayne@69: jpayne@69: typedef struct ZSTD_DDict_s ZSTD_DDict; jpayne@69: jpayne@69: /*! ZSTD_createDDict() : jpayne@69: * Create a digested dictionary, ready to start decompression operation without startup delay. jpayne@69: * dictBuffer can be released after DDict creation, as its content is copied inside DDict. */ jpayne@69: ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_freeDDict() : jpayne@69: * Function frees memory allocated with ZSTD_createDDict() jpayne@69: * If a NULL pointer is passed, no operation is performed. */ jpayne@69: ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict); jpayne@69: jpayne@69: /*! ZSTD_decompress_usingDDict() : jpayne@69: * Decompression using a digested Dictionary. jpayne@69: * Recommended when same dictionary is used multiple times. */ jpayne@69: ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: const ZSTD_DDict* ddict); jpayne@69: jpayne@69: jpayne@69: /******************************** jpayne@69: * Dictionary helper functions jpayne@69: *******************************/ jpayne@69: jpayne@69: /*! ZSTD_getDictID_fromDict() : Requires v1.4.0+ jpayne@69: * Provides the dictID stored within dictionary. jpayne@69: * if @return == 0, the dictionary is not conformant with Zstandard specification. jpayne@69: * It can still be loaded, but as a content-only dictionary. */ jpayne@69: ZSTDLIB_API unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_getDictID_fromCDict() : Requires v1.5.0+ jpayne@69: * Provides the dictID of the dictionary loaded into `cdict`. jpayne@69: * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. jpayne@69: * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */ jpayne@69: ZSTDLIB_API unsigned ZSTD_getDictID_fromCDict(const ZSTD_CDict* cdict); jpayne@69: jpayne@69: /*! ZSTD_getDictID_fromDDict() : Requires v1.4.0+ jpayne@69: * Provides the dictID of the dictionary loaded into `ddict`. jpayne@69: * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. jpayne@69: * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */ jpayne@69: ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict); jpayne@69: jpayne@69: /*! ZSTD_getDictID_fromFrame() : Requires v1.4.0+ jpayne@69: * Provides the dictID required to decompressed the frame stored within `src`. jpayne@69: * If @return == 0, the dictID could not be decoded. jpayne@69: * This could for one of the following reasons : jpayne@69: * - The frame does not require a dictionary to be decoded (most common case). jpayne@69: * - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden piece of information. jpayne@69: * Note : this use case also happens when using a non-conformant dictionary. jpayne@69: * - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`). jpayne@69: * - This is not a Zstandard frame. jpayne@69: * When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */ jpayne@69: ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize); jpayne@69: jpayne@69: jpayne@69: /******************************************************************************* jpayne@69: * Advanced dictionary and prefix API (Requires v1.4.0+) jpayne@69: * jpayne@69: * This API allows dictionaries to be used with ZSTD_compress2(), jpayne@69: * ZSTD_compressStream2(), and ZSTD_decompressDCtx(). jpayne@69: * Dictionaries are sticky, they remain valid when same context is reused, jpayne@69: * they only reset when the context is reset jpayne@69: * with ZSTD_reset_parameters or ZSTD_reset_session_and_parameters. jpayne@69: * In contrast, Prefixes are single-use. jpayne@69: ******************************************************************************/ jpayne@69: jpayne@69: jpayne@69: /*! ZSTD_CCtx_loadDictionary() : Requires v1.4.0+ jpayne@69: * Create an internal CDict from `dict` buffer. jpayne@69: * Decompression will have to use same dictionary. jpayne@69: * @result : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: * Special: Loading a NULL (or 0-size) dictionary invalidates previous dictionary, jpayne@69: * meaning "return to no-dictionary mode". jpayne@69: * Note 1 : Dictionary is sticky, it will be used for all future compressed frames, jpayne@69: * until parameters are reset, a new dictionary is loaded, or the dictionary jpayne@69: * is explicitly invalidated by loading a NULL dictionary. jpayne@69: * Note 2 : Loading a dictionary involves building tables. jpayne@69: * It's also a CPU consuming operation, with non-negligible impact on latency. jpayne@69: * Tables are dependent on compression parameters, and for this reason, jpayne@69: * compression parameters can no longer be changed after loading a dictionary. jpayne@69: * Note 3 :`dict` content will be copied internally. jpayne@69: * Use experimental ZSTD_CCtx_loadDictionary_byReference() to reference content instead. jpayne@69: * In such a case, dictionary buffer must outlive its users. jpayne@69: * Note 4 : Use ZSTD_CCtx_loadDictionary_advanced() jpayne@69: * to precisely select how dictionary content must be interpreted. jpayne@69: * Note 5 : This method does not benefit from LDM (long distance mode). jpayne@69: * If you want to employ LDM on some large dictionary content, jpayne@69: * prefer employing ZSTD_CCtx_refPrefix() described below. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_CCtx_refCDict() : Requires v1.4.0+ jpayne@69: * Reference a prepared dictionary, to be used for all future compressed frames. jpayne@69: * Note that compression parameters are enforced from within CDict, jpayne@69: * and supersede any compression parameter previously set within CCtx. jpayne@69: * The parameters ignored are labelled as "superseded-by-cdict" in the ZSTD_cParameter enum docs. jpayne@69: * The ignored parameters will be used again if the CCtx is returned to no-dictionary mode. jpayne@69: * The dictionary will remain valid for future compressed frames using same CCtx. jpayne@69: * @result : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: * Special : Referencing a NULL CDict means "return to no-dictionary mode". jpayne@69: * Note 1 : Currently, only one dictionary can be managed. jpayne@69: * Referencing a new dictionary effectively "discards" any previous one. jpayne@69: * Note 2 : CDict is just referenced, its lifetime must outlive its usage within CCtx. */ jpayne@69: ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); jpayne@69: jpayne@69: /*! ZSTD_CCtx_refPrefix() : Requires v1.4.0+ jpayne@69: * Reference a prefix (single-usage dictionary) for next compressed frame. jpayne@69: * A prefix is **only used once**. Tables are discarded at end of frame (ZSTD_e_end). jpayne@69: * Decompression will need same prefix to properly regenerate data. jpayne@69: * Compressing with a prefix is similar in outcome as performing a diff and compressing it, jpayne@69: * but performs much faster, especially during decompression (compression speed is tunable with compression level). jpayne@69: * This method is compatible with LDM (long distance mode). jpayne@69: * @result : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: * Special: Adding any prefix (including NULL) invalidates any previous prefix or dictionary jpayne@69: * Note 1 : Prefix buffer is referenced. It **must** outlive compression. jpayne@69: * Its content must remain unmodified during compression. jpayne@69: * Note 2 : If the intention is to diff some large src data blob with some prior version of itself, jpayne@69: * ensure that the window size is large enough to contain the entire source. jpayne@69: * See ZSTD_c_windowLog. jpayne@69: * Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters. jpayne@69: * It's a CPU consuming operation, with non-negligible impact on latency. jpayne@69: * If there is a need to use the same prefix multiple times, consider loadDictionary instead. jpayne@69: * Note 4 : By default, the prefix is interpreted as raw content (ZSTD_dct_rawContent). jpayne@69: * Use experimental ZSTD_CCtx_refPrefix_advanced() to alter dictionary interpretation. */ jpayne@69: ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, jpayne@69: const void* prefix, size_t prefixSize); jpayne@69: jpayne@69: /*! ZSTD_DCtx_loadDictionary() : Requires v1.4.0+ jpayne@69: * Create an internal DDict from dict buffer, to be used to decompress all future frames. jpayne@69: * The dictionary remains valid for all future frames, until explicitly invalidated, or jpayne@69: * a new dictionary is loaded. jpayne@69: * @result : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: * Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary, jpayne@69: * meaning "return to no-dictionary mode". jpayne@69: * Note 1 : Loading a dictionary involves building tables, jpayne@69: * which has a non-negligible impact on CPU usage and latency. jpayne@69: * It's recommended to "load once, use many times", to amortize the cost jpayne@69: * Note 2 :`dict` content will be copied internally, so `dict` can be released after loading. jpayne@69: * Use ZSTD_DCtx_loadDictionary_byReference() to reference dictionary content instead. jpayne@69: * Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to take control of jpayne@69: * how dictionary content is loaded and interpreted. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_DCtx_refDDict() : Requires v1.4.0+ jpayne@69: * Reference a prepared dictionary, to be used to decompress next frames. jpayne@69: * The dictionary remains active for decompression of future frames using same DCtx. jpayne@69: * jpayne@69: * If called with ZSTD_d_refMultipleDDicts enabled, repeated calls of this function jpayne@69: * will store the DDict references in a table, and the DDict used for decompression jpayne@69: * will be determined at decompression time, as per the dict ID in the frame. jpayne@69: * The memory for the table is allocated on the first call to refDDict, and can be jpayne@69: * freed with ZSTD_freeDCtx(). jpayne@69: * jpayne@69: * If called with ZSTD_d_refMultipleDDicts disabled (the default), only one dictionary jpayne@69: * will be managed, and referencing a dictionary effectively "discards" any previous one. jpayne@69: * jpayne@69: * @result : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: * Special: referencing a NULL DDict means "return to no-dictionary mode". jpayne@69: * Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); jpayne@69: jpayne@69: /*! ZSTD_DCtx_refPrefix() : Requires v1.4.0+ jpayne@69: * Reference a prefix (single-usage dictionary) to decompress next frame. jpayne@69: * This is the reverse operation of ZSTD_CCtx_refPrefix(), jpayne@69: * and must use the same prefix as the one used during compression. jpayne@69: * Prefix is **only used once**. Reference is discarded at end of frame. jpayne@69: * End of frame is reached when ZSTD_decompressStream() returns 0. jpayne@69: * @result : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: * Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary jpayne@69: * Note 2 : Prefix buffer is referenced. It **must** outlive decompression. jpayne@69: * Prefix buffer must remain unmodified up to the end of frame, jpayne@69: * reached when ZSTD_decompressStream() returns 0. jpayne@69: * Note 3 : By default, the prefix is treated as raw content (ZSTD_dct_rawContent). jpayne@69: * Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode (Experimental section) jpayne@69: * Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost. jpayne@69: * A full dictionary is more costly, as it requires building tables. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, jpayne@69: const void* prefix, size_t prefixSize); jpayne@69: jpayne@69: /* === Memory management === */ jpayne@69: jpayne@69: /*! ZSTD_sizeof_*() : Requires v1.4.0+ jpayne@69: * These functions give the _current_ memory usage of selected object. jpayne@69: * Note that object memory usage can evolve (increase or decrease) over time. */ jpayne@69: ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx); jpayne@69: ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx); jpayne@69: ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); jpayne@69: ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); jpayne@69: ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict); jpayne@69: ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); jpayne@69: jpayne@69: #endif /* ZSTD_H_235446 */ jpayne@69: jpayne@69: jpayne@69: /* ************************************************************************************** jpayne@69: * ADVANCED AND EXPERIMENTAL FUNCTIONS jpayne@69: **************************************************************************************** jpayne@69: * The definitions in the following section are considered experimental. jpayne@69: * They are provided for advanced scenarios. jpayne@69: * They should never be used with a dynamic library, as prototypes may change in the future. jpayne@69: * Use them only in association with static linking. jpayne@69: * ***************************************************************************************/ jpayne@69: jpayne@69: #if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY) jpayne@69: #define ZSTD_H_ZSTD_STATIC_LINKING_ONLY jpayne@69: jpayne@69: /* This can be overridden externally to hide static symbols. */ jpayne@69: #ifndef ZSTDLIB_STATIC_API jpayne@69: # if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) jpayne@69: # define ZSTDLIB_STATIC_API __declspec(dllexport) ZSTDLIB_VISIBLE jpayne@69: # elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) jpayne@69: # define ZSTDLIB_STATIC_API __declspec(dllimport) ZSTDLIB_VISIBLE jpayne@69: # else jpayne@69: # define ZSTDLIB_STATIC_API ZSTDLIB_VISIBLE jpayne@69: # endif jpayne@69: #endif jpayne@69: jpayne@69: /**************************************************************************************** jpayne@69: * experimental API (static linking only) jpayne@69: **************************************************************************************** jpayne@69: * The following symbols and constants jpayne@69: * are not planned to join "stable API" status in the near future. jpayne@69: * They can still change in future versions. jpayne@69: * Some of them are planned to remain in the static_only section indefinitely. jpayne@69: * Some of them might be removed in the future (especially when redundant with existing stable functions) jpayne@69: * ***************************************************************************************/ jpayne@69: jpayne@69: #define ZSTD_FRAMEHEADERSIZE_PREFIX(format) ((format) == ZSTD_f_zstd1 ? 5 : 1) /* minimum input size required to query frame header size */ jpayne@69: #define ZSTD_FRAMEHEADERSIZE_MIN(format) ((format) == ZSTD_f_zstd1 ? 6 : 2) jpayne@69: #define ZSTD_FRAMEHEADERSIZE_MAX 18 /* can be useful for static allocation */ jpayne@69: #define ZSTD_SKIPPABLEHEADERSIZE 8 jpayne@69: jpayne@69: /* compression parameter bounds */ jpayne@69: #define ZSTD_WINDOWLOG_MAX_32 30 jpayne@69: #define ZSTD_WINDOWLOG_MAX_64 31 jpayne@69: #define ZSTD_WINDOWLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64)) jpayne@69: #define ZSTD_WINDOWLOG_MIN 10 jpayne@69: #define ZSTD_HASHLOG_MAX ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30) jpayne@69: #define ZSTD_HASHLOG_MIN 6 jpayne@69: #define ZSTD_CHAINLOG_MAX_32 29 jpayne@69: #define ZSTD_CHAINLOG_MAX_64 30 jpayne@69: #define ZSTD_CHAINLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64)) jpayne@69: #define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN jpayne@69: #define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1) jpayne@69: #define ZSTD_SEARCHLOG_MIN 1 jpayne@69: #define ZSTD_MINMATCH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */ jpayne@69: #define ZSTD_MINMATCH_MIN 3 /* only for ZSTD_btopt+, faster strategies are limited to 4 */ jpayne@69: #define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX jpayne@69: #define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */ jpayne@69: #define ZSTD_STRATEGY_MIN ZSTD_fast jpayne@69: #define ZSTD_STRATEGY_MAX ZSTD_btultra2 jpayne@69: #define ZSTD_BLOCKSIZE_MAX_MIN (1 << 10) /* The minimum valid max blocksize. Maximum blocksizes smaller than this make compressBound() inaccurate. */ jpayne@69: jpayne@69: jpayne@69: #define ZSTD_OVERLAPLOG_MIN 0 jpayne@69: #define ZSTD_OVERLAPLOG_MAX 9 jpayne@69: jpayne@69: #define ZSTD_WINDOWLOG_LIMIT_DEFAULT 27 /* by default, the streaming decoder will refuse any frame jpayne@69: * requiring larger than (1< 0: jpayne@69: * If litLength != 0: jpayne@69: * rep == 1 --> offset == repeat_offset_1 jpayne@69: * rep == 2 --> offset == repeat_offset_2 jpayne@69: * rep == 3 --> offset == repeat_offset_3 jpayne@69: * If litLength == 0: jpayne@69: * rep == 1 --> offset == repeat_offset_2 jpayne@69: * rep == 2 --> offset == repeat_offset_3 jpayne@69: * rep == 3 --> offset == repeat_offset_1 - 1 jpayne@69: * jpayne@69: * Note: This field is optional. ZSTD_generateSequences() will calculate the value of jpayne@69: * 'rep', but repeat offsets do not necessarily need to be calculated from an external jpayne@69: * sequence provider's perspective. For example, ZSTD_compressSequences() does not jpayne@69: * use this 'rep' field at all (as of now). jpayne@69: */ jpayne@69: } ZSTD_Sequence; jpayne@69: jpayne@69: typedef struct { jpayne@69: unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */ jpayne@69: unsigned chainLog; /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */ jpayne@69: unsigned hashLog; /**< dispatch table : larger == faster, more memory */ jpayne@69: unsigned searchLog; /**< nb of searches : larger == more compression, slower */ jpayne@69: unsigned minMatch; /**< match length searched : larger == faster decompression, sometimes less compression */ jpayne@69: unsigned targetLength; /**< acceptable match size for optimal parser (only) : larger == more compression, slower */ jpayne@69: ZSTD_strategy strategy; /**< see ZSTD_strategy definition above */ jpayne@69: } ZSTD_compressionParameters; jpayne@69: jpayne@69: typedef struct { jpayne@69: int contentSizeFlag; /**< 1: content size will be in frame header (when known) */ jpayne@69: int checksumFlag; /**< 1: generate a 32-bits checksum using XXH64 algorithm at end of frame, for error detection */ jpayne@69: int noDictIDFlag; /**< 1: no dictID will be saved into frame header (dictID is only useful for dictionary compression) */ jpayne@69: } ZSTD_frameParameters; jpayne@69: jpayne@69: typedef struct { jpayne@69: ZSTD_compressionParameters cParams; jpayne@69: ZSTD_frameParameters fParams; jpayne@69: } ZSTD_parameters; jpayne@69: jpayne@69: typedef enum { jpayne@69: ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */ jpayne@69: ZSTD_dct_rawContent = 1, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */ jpayne@69: ZSTD_dct_fullDict = 2 /* refuses to load a dictionary if it does not respect Zstandard's specification, starting with ZSTD_MAGIC_DICTIONARY */ jpayne@69: } ZSTD_dictContentType_e; jpayne@69: jpayne@69: typedef enum { jpayne@69: ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */ jpayne@69: ZSTD_dlm_byRef = 1 /**< Reference dictionary content -- the dictionary buffer must outlive its users. */ jpayne@69: } ZSTD_dictLoadMethod_e; jpayne@69: jpayne@69: typedef enum { jpayne@69: ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */ jpayne@69: ZSTD_f_zstd1_magicless = 1 /* Variant of zstd frame format, without initial 4-bytes magic number. jpayne@69: * Useful to save 4 bytes per generated frame. jpayne@69: * Decoder cannot recognise automatically this format, requiring this instruction. */ jpayne@69: } ZSTD_format_e; jpayne@69: jpayne@69: typedef enum { jpayne@69: /* Note: this enum controls ZSTD_d_forceIgnoreChecksum */ jpayne@69: ZSTD_d_validateChecksum = 0, jpayne@69: ZSTD_d_ignoreChecksum = 1 jpayne@69: } ZSTD_forceIgnoreChecksum_e; jpayne@69: jpayne@69: typedef enum { jpayne@69: /* Note: this enum controls ZSTD_d_refMultipleDDicts */ jpayne@69: ZSTD_rmd_refSingleDDict = 0, jpayne@69: ZSTD_rmd_refMultipleDDicts = 1 jpayne@69: } ZSTD_refMultipleDDicts_e; jpayne@69: jpayne@69: typedef enum { jpayne@69: /* Note: this enum and the behavior it controls are effectively internal jpayne@69: * implementation details of the compressor. They are expected to continue jpayne@69: * to evolve and should be considered only in the context of extremely jpayne@69: * advanced performance tuning. jpayne@69: * jpayne@69: * Zstd currently supports the use of a CDict in three ways: jpayne@69: * jpayne@69: * - The contents of the CDict can be copied into the working context. This jpayne@69: * means that the compression can search both the dictionary and input jpayne@69: * while operating on a single set of internal tables. This makes jpayne@69: * the compression faster per-byte of input. However, the initial copy of jpayne@69: * the CDict's tables incurs a fixed cost at the beginning of the jpayne@69: * compression. For small compressions (< 8 KB), that copy can dominate jpayne@69: * the cost of the compression. jpayne@69: * jpayne@69: * - The CDict's tables can be used in-place. In this model, compression is jpayne@69: * slower per input byte, because the compressor has to search two sets of jpayne@69: * tables. However, this model incurs no start-up cost (as long as the jpayne@69: * working context's tables can be reused). For small inputs, this can be jpayne@69: * faster than copying the CDict's tables. jpayne@69: * jpayne@69: * - The CDict's tables are not used at all, and instead we use the working jpayne@69: * context alone to reload the dictionary and use params based on the source jpayne@69: * size. See ZSTD_compress_insertDictionary() and ZSTD_compress_usingDict(). jpayne@69: * This method is effective when the dictionary sizes are very small relative jpayne@69: * to the input size, and the input size is fairly large to begin with. jpayne@69: * jpayne@69: * Zstd has a simple internal heuristic that selects which strategy to use jpayne@69: * at the beginning of a compression. However, if experimentation shows that jpayne@69: * Zstd is making poor choices, it is possible to override that choice with jpayne@69: * this enum. jpayne@69: */ jpayne@69: ZSTD_dictDefaultAttach = 0, /* Use the default heuristic. */ jpayne@69: ZSTD_dictForceAttach = 1, /* Never copy the dictionary. */ jpayne@69: ZSTD_dictForceCopy = 2, /* Always copy the dictionary. */ jpayne@69: ZSTD_dictForceLoad = 3 /* Always reload the dictionary */ jpayne@69: } ZSTD_dictAttachPref_e; jpayne@69: jpayne@69: typedef enum { jpayne@69: ZSTD_lcm_auto = 0, /**< Automatically determine the compression mode based on the compression level. jpayne@69: * Negative compression levels will be uncompressed, and positive compression jpayne@69: * levels will be compressed. */ jpayne@69: ZSTD_lcm_huffman = 1, /**< Always attempt Huffman compression. Uncompressed literals will still be jpayne@69: * emitted if Huffman compression is not profitable. */ jpayne@69: ZSTD_lcm_uncompressed = 2 /**< Always emit uncompressed literals. */ jpayne@69: } ZSTD_literalCompressionMode_e; jpayne@69: jpayne@69: typedef enum { jpayne@69: /* Note: This enum controls features which are conditionally beneficial. Zstd typically will make a final jpayne@69: * decision on whether or not to enable the feature (ZSTD_ps_auto), but setting the switch to ZSTD_ps_enable jpayne@69: * or ZSTD_ps_disable allow for a force enable/disable the feature. jpayne@69: */ jpayne@69: ZSTD_ps_auto = 0, /* Let the library automatically determine whether the feature shall be enabled */ jpayne@69: ZSTD_ps_enable = 1, /* Force-enable the feature */ jpayne@69: ZSTD_ps_disable = 2 /* Do not use the feature */ jpayne@69: } ZSTD_paramSwitch_e; jpayne@69: jpayne@69: /*************************************** jpayne@69: * Frame header and size functions jpayne@69: ***************************************/ jpayne@69: jpayne@69: /*! ZSTD_findDecompressedSize() : jpayne@69: * `src` should point to the start of a series of ZSTD encoded and/or skippable frames jpayne@69: * `srcSize` must be the _exact_ size of this series jpayne@69: * (i.e. there should be a frame boundary at `src + srcSize`) jpayne@69: * @return : - decompressed size of all data in all successive frames jpayne@69: * - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN jpayne@69: * - if an error occurred: ZSTD_CONTENTSIZE_ERROR jpayne@69: * jpayne@69: * note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode. jpayne@69: * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. jpayne@69: * In which case, it's necessary to use streaming mode to decompress data. jpayne@69: * note 2 : decompressed size is always present when compression is done with ZSTD_compress() jpayne@69: * note 3 : decompressed size can be very large (64-bits value), jpayne@69: * potentially larger than what local system can handle as a single memory segment. jpayne@69: * In which case, it's necessary to use streaming mode to decompress data. jpayne@69: * note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified. jpayne@69: * Always ensure result fits within application's authorized limits. jpayne@69: * Each application can set its own limits. jpayne@69: * note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to jpayne@69: * read each contained frame header. This is fast as most of the data is skipped, jpayne@69: * however it does mean that all frame data must be present and valid. */ jpayne@69: ZSTDLIB_STATIC_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_decompressBound() : jpayne@69: * `src` should point to the start of a series of ZSTD encoded and/or skippable frames jpayne@69: * `srcSize` must be the _exact_ size of this series jpayne@69: * (i.e. there should be a frame boundary at `src + srcSize`) jpayne@69: * @return : - upper-bound for the decompressed size of all data in all successive frames jpayne@69: * - if an error occurred: ZSTD_CONTENTSIZE_ERROR jpayne@69: * jpayne@69: * note 1 : an error can occur if `src` contains an invalid or incorrectly formatted frame. jpayne@69: * note 2 : the upper-bound is exact when the decompressed size field is available in every ZSTD encoded frame of `src`. jpayne@69: * in this case, `ZSTD_findDecompressedSize` and `ZSTD_decompressBound` return the same value. jpayne@69: * note 3 : when the decompressed size field isn't available, the upper-bound for that frame is calculated by: jpayne@69: * upper-bound = # blocks * min(128 KB, Window_Size) jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_frameHeaderSize() : jpayne@69: * srcSize must be >= ZSTD_FRAMEHEADERSIZE_PREFIX. jpayne@69: * @return : size of the Frame Header, jpayne@69: * or an error code (if srcSize is too small) */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize); jpayne@69: jpayne@69: typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e; jpayne@69: typedef struct { jpayne@69: unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */ jpayne@69: unsigned long long windowSize; /* can be very large, up to <= frameContentSize */ jpayne@69: unsigned blockSizeMax; jpayne@69: ZSTD_frameType_e frameType; /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */ jpayne@69: unsigned headerSize; jpayne@69: unsigned dictID; jpayne@69: unsigned checksumFlag; jpayne@69: unsigned _reserved1; jpayne@69: unsigned _reserved2; jpayne@69: } ZSTD_frameHeader; jpayne@69: jpayne@69: /*! ZSTD_getFrameHeader() : jpayne@69: * decode Frame Header, or requires larger `srcSize`. jpayne@69: * @return : 0, `zfhPtr` is correctly filled, jpayne@69: * >0, `srcSize` is too small, value is wanted `srcSize` amount, jpayne@69: * or an error code, which can be tested using ZSTD_isError() */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /**< doesn't consume input */ jpayne@69: /*! ZSTD_getFrameHeader_advanced() : jpayne@69: * same as ZSTD_getFrameHeader(), jpayne@69: * with added capability to select a format (like ZSTD_f_zstd1_magicless) */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format); jpayne@69: jpayne@69: /*! ZSTD_decompressionMargin() : jpayne@69: * Zstd supports in-place decompression, where the input and output buffers overlap. jpayne@69: * In this case, the output buffer must be at least (Margin + Output_Size) bytes large, jpayne@69: * and the input buffer must be at the end of the output buffer. jpayne@69: * jpayne@69: * _______________________ Output Buffer ________________________ jpayne@69: * | | jpayne@69: * | ____ Input Buffer ____| jpayne@69: * | | | jpayne@69: * v v v jpayne@69: * |---------------------------------------|-----------|----------| jpayne@69: * ^ ^ ^ jpayne@69: * |___________________ Output_Size ___________________|_ Margin _| jpayne@69: * jpayne@69: * NOTE: See also ZSTD_DECOMPRESSION_MARGIN(). jpayne@69: * NOTE: This applies only to single-pass decompression through ZSTD_decompress() or jpayne@69: * ZSTD_decompressDCtx(). jpayne@69: * NOTE: This function supports multi-frame input. jpayne@69: * jpayne@69: * @param src The compressed frame(s) jpayne@69: * @param srcSize The size of the compressed frame(s) jpayne@69: * @returns The decompression margin or an error that can be checked with ZSTD_isError(). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_decompressionMargin(const void* src, size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_DECOMPRESS_MARGIN() : jpayne@69: * Similar to ZSTD_decompressionMargin(), but instead of computing the margin from jpayne@69: * the compressed frame, compute it from the original size and the blockSizeLog. jpayne@69: * See ZSTD_decompressionMargin() for details. jpayne@69: * jpayne@69: * WARNING: This macro does not support multi-frame input, the input must be a single jpayne@69: * zstd frame. If you need that support use the function, or implement it yourself. jpayne@69: * jpayne@69: * @param originalSize The original uncompressed size of the data. jpayne@69: * @param blockSize The block size == MIN(windowSize, ZSTD_BLOCKSIZE_MAX). jpayne@69: * Unless you explicitly set the windowLog smaller than jpayne@69: * ZSTD_BLOCKSIZELOG_MAX you can just use ZSTD_BLOCKSIZE_MAX. jpayne@69: */ jpayne@69: #define ZSTD_DECOMPRESSION_MARGIN(originalSize, blockSize) ((size_t)( \ jpayne@69: ZSTD_FRAMEHEADERSIZE_MAX /* Frame header */ + \ jpayne@69: 4 /* checksum */ + \ jpayne@69: ((originalSize) == 0 ? 0 : 3 * (((originalSize) + (blockSize) - 1) / blockSize)) /* 3 bytes per block */ + \ jpayne@69: (blockSize) /* One block of margin */ \ jpayne@69: )) jpayne@69: jpayne@69: typedef enum { jpayne@69: ZSTD_sf_noBlockDelimiters = 0, /* Representation of ZSTD_Sequence has no block delimiters, sequences only */ jpayne@69: ZSTD_sf_explicitBlockDelimiters = 1 /* Representation of ZSTD_Sequence contains explicit block delimiters */ jpayne@69: } ZSTD_sequenceFormat_e; jpayne@69: jpayne@69: /*! ZSTD_sequenceBound() : jpayne@69: * `srcSize` : size of the input buffer jpayne@69: * @return : upper-bound for the number of sequences that can be generated jpayne@69: * from a buffer of srcSize bytes jpayne@69: * jpayne@69: * note : returns number of sequences - to get bytes, multiply by sizeof(ZSTD_Sequence). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_sequenceBound(size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_generateSequences() : jpayne@69: * WARNING: This function is meant for debugging and informational purposes ONLY! jpayne@69: * Its implementation is flawed, and it will be deleted in a future version. jpayne@69: * It is not guaranteed to succeed, as there are several cases where it will give jpayne@69: * up and fail. You should NOT use this function in production code. jpayne@69: * jpayne@69: * This function is deprecated, and will be removed in a future version. jpayne@69: * jpayne@69: * Generate sequences using ZSTD_compress2(), given a source buffer. jpayne@69: * jpayne@69: * @param zc The compression context to be used for ZSTD_compress2(). Set any jpayne@69: * compression parameters you need on this context. jpayne@69: * @param outSeqs The output sequences buffer of size @p outSeqsSize jpayne@69: * @param outSeqsSize The size of the output sequences buffer. jpayne@69: * ZSTD_sequenceBound(srcSize) is an upper bound on the number jpayne@69: * of sequences that can be generated. jpayne@69: * @param src The source buffer to generate sequences from of size @p srcSize. jpayne@69: * @param srcSize The size of the source buffer. jpayne@69: * jpayne@69: * Each block will end with a dummy sequence jpayne@69: * with offset == 0, matchLength == 0, and litLength == length of last literals. jpayne@69: * litLength may be == 0, and if so, then the sequence of (of: 0 ml: 0 ll: 0) jpayne@69: * simply acts as a block delimiter. jpayne@69: * jpayne@69: * @returns The number of sequences generated, necessarily less than jpayne@69: * ZSTD_sequenceBound(srcSize), or an error code that can be checked jpayne@69: * with ZSTD_isError(). jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("For debugging only, will be replaced by ZSTD_extractSequences()") jpayne@69: ZSTDLIB_STATIC_API size_t jpayne@69: ZSTD_generateSequences(ZSTD_CCtx* zc, jpayne@69: ZSTD_Sequence* outSeqs, size_t outSeqsSize, jpayne@69: const void* src, size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_mergeBlockDelimiters() : jpayne@69: * Given an array of ZSTD_Sequence, remove all sequences that represent block delimiters/last literals jpayne@69: * by merging them into the literals of the next sequence. jpayne@69: * jpayne@69: * As such, the final generated result has no explicit representation of block boundaries, jpayne@69: * and the final last literals segment is not represented in the sequences. jpayne@69: * jpayne@69: * The output of this function can be fed into ZSTD_compressSequences() with CCtx jpayne@69: * setting of ZSTD_c_blockDelimiters as ZSTD_sf_noBlockDelimiters jpayne@69: * @return : number of sequences left after merging jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, size_t seqsSize); jpayne@69: jpayne@69: /*! ZSTD_compressSequences() : jpayne@69: * Compress an array of ZSTD_Sequence, associated with @src buffer, into dst. jpayne@69: * @src contains the entire input (not just the literals). jpayne@69: * If @srcSize > sum(sequence.length), the remaining bytes are considered all literals jpayne@69: * If a dictionary is included, then the cctx should reference the dict. (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.) jpayne@69: * The entire source is compressed into a single frame. jpayne@69: * jpayne@69: * The compression behavior changes based on cctx params. In particular: jpayne@69: * If ZSTD_c_blockDelimiters == ZSTD_sf_noBlockDelimiters, the array of ZSTD_Sequence is expected to contain jpayne@69: * no block delimiters (defined in ZSTD_Sequence). Block boundaries are roughly determined based on jpayne@69: * the block size derived from the cctx, and sequences may be split. This is the default setting. jpayne@69: * jpayne@69: * If ZSTD_c_blockDelimiters == ZSTD_sf_explicitBlockDelimiters, the array of ZSTD_Sequence is expected to contain jpayne@69: * block delimiters (defined in ZSTD_Sequence). Behavior is undefined if no block delimiters are provided. jpayne@69: * jpayne@69: * If ZSTD_c_validateSequences == 0, this function will blindly accept the sequences provided. Invalid sequences cause undefined jpayne@69: * behavior. If ZSTD_c_validateSequences == 1, then if sequence is invalid (see doc/zstd_compression_format.md for jpayne@69: * specifics regarding offset/matchlength requirements) then the function will bail out and return an error. jpayne@69: * jpayne@69: * In addition to the two adjustable experimental params, there are other important cctx params. jpayne@69: * - ZSTD_c_minMatch MUST be set as less than or equal to the smallest match generated by the match finder. It has a minimum value of ZSTD_MINMATCH_MIN. jpayne@69: * - ZSTD_c_compressionLevel accordingly adjusts the strength of the entropy coder, as it would in typical compression. jpayne@69: * - ZSTD_c_windowLog affects offset validation: this function will return an error at higher debug levels if a provided offset jpayne@69: * is larger than what the spec allows for a given window log and dictionary (if present). See: doc/zstd_compression_format.md jpayne@69: * jpayne@69: * Note: Repcodes are, as of now, always re-calculated within this function, so ZSTD_Sequence::rep is unused. jpayne@69: * Note 2: Once we integrate ability to ingest repcodes, the explicit block delims mode must respect those repcodes exactly, jpayne@69: * and cannot emit an RLE block that disagrees with the repcode history jpayne@69: * @return : final compressed size, or a ZSTD error code. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t jpayne@69: ZSTD_compressSequences( ZSTD_CCtx* cctx, void* dst, size_t dstSize, jpayne@69: const ZSTD_Sequence* inSeqs, size_t inSeqsSize, jpayne@69: const void* src, size_t srcSize); jpayne@69: jpayne@69: jpayne@69: /*! ZSTD_writeSkippableFrame() : jpayne@69: * Generates a zstd skippable frame containing data given by src, and writes it to dst buffer. jpayne@69: * jpayne@69: * Skippable frames begin with a 4-byte magic number. There are 16 possible choices of magic number, jpayne@69: * ranging from ZSTD_MAGIC_SKIPPABLE_START to ZSTD_MAGIC_SKIPPABLE_START+15. jpayne@69: * As such, the parameter magicVariant controls the exact skippable frame magic number variant used, so jpayne@69: * the magic number used will be ZSTD_MAGIC_SKIPPABLE_START + magicVariant. jpayne@69: * jpayne@69: * Returns an error if destination buffer is not large enough, if the source size is not representable jpayne@69: * with a 4-byte unsigned int, or if the parameter magicVariant is greater than 15 (and therefore invalid). jpayne@69: * jpayne@69: * @return : number of bytes written or a ZSTD error. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_writeSkippableFrame(void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, unsigned magicVariant); jpayne@69: jpayne@69: /*! ZSTD_readSkippableFrame() : jpayne@69: * Retrieves a zstd skippable frame containing data given by src, and writes it to dst buffer. jpayne@69: * jpayne@69: * The parameter magicVariant will receive the magicVariant that was supplied when the frame was written, jpayne@69: * i.e. magicNumber - ZSTD_MAGIC_SKIPPABLE_START. This can be NULL if the caller is not interested jpayne@69: * in the magicVariant. jpayne@69: * jpayne@69: * Returns an error if destination buffer is not large enough, or if the frame is not skippable. jpayne@69: * jpayne@69: * @return : number of bytes written or a ZSTD error. jpayne@69: */ jpayne@69: ZSTDLIB_API size_t ZSTD_readSkippableFrame(void* dst, size_t dstCapacity, unsigned* magicVariant, jpayne@69: const void* src, size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_isSkippableFrame() : jpayne@69: * Tells if the content of `buffer` starts with a valid Frame Identifier for a skippable frame. jpayne@69: */ jpayne@69: ZSTDLIB_API unsigned ZSTD_isSkippableFrame(const void* buffer, size_t size); jpayne@69: jpayne@69: jpayne@69: jpayne@69: /*************************************** jpayne@69: * Memory management jpayne@69: ***************************************/ jpayne@69: jpayne@69: /*! ZSTD_estimate*() : jpayne@69: * These functions make it possible to estimate memory usage jpayne@69: * of a future {D,C}Ctx, before its creation. jpayne@69: * This is useful in combination with ZSTD_initStatic(), jpayne@69: * which makes it possible to employ a static buffer for ZSTD_CCtx* state. jpayne@69: * jpayne@69: * ZSTD_estimateCCtxSize() will provide a memory budget large enough jpayne@69: * to compress data of any size using one-shot compression ZSTD_compressCCtx() or ZSTD_compress2() jpayne@69: * associated with any compression level up to max specified one. jpayne@69: * The estimate will assume the input may be arbitrarily large, jpayne@69: * which is the worst case. jpayne@69: * jpayne@69: * Note that the size estimation is specific for one-shot compression, jpayne@69: * it is not valid for streaming (see ZSTD_estimateCStreamSize*()) jpayne@69: * nor other potential ways of using a ZSTD_CCtx* state. jpayne@69: * jpayne@69: * When srcSize can be bound by a known and rather "small" value, jpayne@69: * this knowledge can be used to provide a tighter budget estimation jpayne@69: * because the ZSTD_CCtx* state will need less memory for small inputs. jpayne@69: * This tighter estimation can be provided by employing more advanced functions jpayne@69: * ZSTD_estimateCCtxSize_usingCParams(), which can be used in tandem with ZSTD_getCParams(), jpayne@69: * and ZSTD_estimateCCtxSize_usingCCtxParams(), which can be used in tandem with ZSTD_CCtxParams_setParameter(). jpayne@69: * Both can be used to estimate memory using custom compression parameters and arbitrary srcSize limits. jpayne@69: * jpayne@69: * Note : only single-threaded compression is supported. jpayne@69: * ZSTD_estimateCCtxSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize(int maxCompressionLevel); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateDCtxSize(void); jpayne@69: jpayne@69: /*! ZSTD_estimateCStreamSize() : jpayne@69: * ZSTD_estimateCStreamSize() will provide a memory budget large enough for streaming compression jpayne@69: * using any compression level up to the max specified one. jpayne@69: * It will also consider src size to be arbitrarily "large", which is a worst case scenario. jpayne@69: * If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation. jpayne@69: * ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. jpayne@69: * ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParams_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_c_nbWorkers is >= 1. jpayne@69: * Note : CStream size estimation is only correct for single-threaded compression. jpayne@69: * ZSTD_estimateCStreamSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1. jpayne@69: * Note 2 : ZSTD_estimateCStreamSize* functions are not compatible with the Block-Level Sequence Producer API at this time. jpayne@69: * Size estimates assume that no external sequence producer is registered. jpayne@69: * jpayne@69: * ZSTD_DStream memory budget depends on frame's window Size. jpayne@69: * This information can be passed manually, using ZSTD_estimateDStreamSize, jpayne@69: * or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame(); jpayne@69: * Any frame requesting a window size larger than max specified one will be rejected. jpayne@69: * Note : if streaming is init with function ZSTD_init?Stream_usingDict(), jpayne@69: * an internal ?Dict will be created, which additional size is not estimated here. jpayne@69: * In this case, get total size by adding ZSTD_estimate?DictSize jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize(int maxCompressionLevel); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateDStreamSize(size_t maxWindowSize); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize); jpayne@69: jpayne@69: /*! ZSTD_estimate?DictSize() : jpayne@69: * ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict(). jpayne@69: * ZSTD_estimateCDictSize_advanced() makes it possible to control compression parameters precisely, like ZSTD_createCDict_advanced(). jpayne@69: * Note : dictionaries created by reference (`ZSTD_dlm_byRef`) are logically smaller. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod); jpayne@69: jpayne@69: /*! ZSTD_initStatic*() : jpayne@69: * Initialize an object using a pre-allocated fixed-size buffer. jpayne@69: * workspace: The memory area to emplace the object into. jpayne@69: * Provided pointer *must be 8-bytes aligned*. jpayne@69: * Buffer must outlive object. jpayne@69: * workspaceSize: Use ZSTD_estimate*Size() to determine jpayne@69: * how large workspace must be to support target scenario. jpayne@69: * @return : pointer to object (same address as workspace, just different type), jpayne@69: * or NULL if error (size too small, incorrect alignment, etc.) jpayne@69: * Note : zstd will never resize nor malloc() when using a static buffer. jpayne@69: * If the object requires more memory than available, jpayne@69: * zstd will just error out (typically ZSTD_error_memory_allocation). jpayne@69: * Note 2 : there is no corresponding "free" function. jpayne@69: * Since workspace is allocated externally, it must be freed externally too. jpayne@69: * Note 3 : cParams : use ZSTD_getCParams() to convert a compression level jpayne@69: * into its associated cParams. jpayne@69: * Limitation 1 : currently not compatible with internal dictionary creation, triggered by jpayne@69: * ZSTD_CCtx_loadDictionary(), ZSTD_initCStream_usingDict() or ZSTD_initDStream_usingDict(). jpayne@69: * Limitation 2 : static cctx currently not compatible with multi-threading. jpayne@69: * Limitation 3 : static dctx is incompatible with legacy support. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize); jpayne@69: ZSTDLIB_STATIC_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */ jpayne@69: jpayne@69: ZSTDLIB_STATIC_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize); jpayne@69: ZSTDLIB_STATIC_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */ jpayne@69: jpayne@69: ZSTDLIB_STATIC_API const ZSTD_CDict* ZSTD_initStaticCDict( jpayne@69: void* workspace, size_t workspaceSize, jpayne@69: const void* dict, size_t dictSize, jpayne@69: ZSTD_dictLoadMethod_e dictLoadMethod, jpayne@69: ZSTD_dictContentType_e dictContentType, jpayne@69: ZSTD_compressionParameters cParams); jpayne@69: jpayne@69: ZSTDLIB_STATIC_API const ZSTD_DDict* ZSTD_initStaticDDict( jpayne@69: void* workspace, size_t workspaceSize, jpayne@69: const void* dict, size_t dictSize, jpayne@69: ZSTD_dictLoadMethod_e dictLoadMethod, jpayne@69: ZSTD_dictContentType_e dictContentType); jpayne@69: jpayne@69: jpayne@69: /*! Custom memory allocation : jpayne@69: * These prototypes make it possible to pass your own allocation/free functions. jpayne@69: * ZSTD_customMem is provided at creation time, using ZSTD_create*_advanced() variants listed below. jpayne@69: * All allocation/free operations will be completed using these custom variants instead of regular ones. jpayne@69: */ jpayne@69: typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size); jpayne@69: typedef void (*ZSTD_freeFunction) (void* opaque, void* address); jpayne@69: typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem; jpayne@69: static jpayne@69: #ifdef __GNUC__ jpayne@69: __attribute__((__unused__)) jpayne@69: #endif jpayne@69: ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /**< this constant defers to stdlib's functions */ jpayne@69: jpayne@69: ZSTDLIB_STATIC_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem); jpayne@69: ZSTDLIB_STATIC_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); jpayne@69: ZSTDLIB_STATIC_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem); jpayne@69: ZSTDLIB_STATIC_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem); jpayne@69: jpayne@69: ZSTDLIB_STATIC_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, jpayne@69: ZSTD_dictLoadMethod_e dictLoadMethod, jpayne@69: ZSTD_dictContentType_e dictContentType, jpayne@69: ZSTD_compressionParameters cParams, jpayne@69: ZSTD_customMem customMem); jpayne@69: jpayne@69: /*! Thread pool : jpayne@69: * These prototypes make it possible to share a thread pool among multiple compression contexts. jpayne@69: * This can limit resources for applications with multiple threads where each one uses jpayne@69: * a threaded compression mode (via ZSTD_c_nbWorkers parameter). jpayne@69: * ZSTD_createThreadPool creates a new thread pool with a given number of threads. jpayne@69: * Note that the lifetime of such pool must exist while being used. jpayne@69: * ZSTD_CCtx_refThreadPool assigns a thread pool to a context (use NULL argument value jpayne@69: * to use an internal thread pool). jpayne@69: * ZSTD_freeThreadPool frees a thread pool, accepts NULL pointer. jpayne@69: */ jpayne@69: typedef struct POOL_ctx_s ZSTD_threadPool; jpayne@69: ZSTDLIB_STATIC_API ZSTD_threadPool* ZSTD_createThreadPool(size_t numThreads); jpayne@69: ZSTDLIB_STATIC_API void ZSTD_freeThreadPool (ZSTD_threadPool* pool); /* accept NULL pointer */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_refThreadPool(ZSTD_CCtx* cctx, ZSTD_threadPool* pool); jpayne@69: jpayne@69: jpayne@69: /* jpayne@69: * This API is temporary and is expected to change or disappear in the future! jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_CDict* ZSTD_createCDict_advanced2( jpayne@69: const void* dict, size_t dictSize, jpayne@69: ZSTD_dictLoadMethod_e dictLoadMethod, jpayne@69: ZSTD_dictContentType_e dictContentType, jpayne@69: const ZSTD_CCtx_params* cctxParams, jpayne@69: ZSTD_customMem customMem); jpayne@69: jpayne@69: ZSTDLIB_STATIC_API ZSTD_DDict* ZSTD_createDDict_advanced( jpayne@69: const void* dict, size_t dictSize, jpayne@69: ZSTD_dictLoadMethod_e dictLoadMethod, jpayne@69: ZSTD_dictContentType_e dictContentType, jpayne@69: ZSTD_customMem customMem); jpayne@69: jpayne@69: jpayne@69: /*************************************** jpayne@69: * Advanced compression functions jpayne@69: ***************************************/ jpayne@69: jpayne@69: /*! ZSTD_createCDict_byReference() : jpayne@69: * Create a digested dictionary for compression jpayne@69: * Dictionary content is just referenced, not duplicated. jpayne@69: * As a consequence, `dictBuffer` **must** outlive CDict, jpayne@69: * and its content must remain unmodified throughout the lifetime of CDict. jpayne@69: * note: equivalent to ZSTD_createCDict_advanced(), with dictLoadMethod==ZSTD_dlm_byRef */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel); jpayne@69: jpayne@69: /*! ZSTD_getCParams() : jpayne@69: * @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize. jpayne@69: * `estimatedSrcSize` value is optional, select 0 if not known */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_getParams() : jpayne@69: * same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`. jpayne@69: * All fields of `ZSTD_frameParameters` are set to default : contentSize=1, checksum=0, noDictID=0 */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_checkCParams() : jpayne@69: * Ensure param values remain within authorized range. jpayne@69: * @return 0 on success, or an error code (can be checked with ZSTD_isError()) */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params); jpayne@69: jpayne@69: /*! ZSTD_adjustCParams() : jpayne@69: * optimize params for a given `srcSize` and `dictSize`. jpayne@69: * `srcSize` can be unknown, in which case use ZSTD_CONTENTSIZE_UNKNOWN. jpayne@69: * `dictSize` must be `0` when there is no dictionary. jpayne@69: * cPar can be invalid : all parameters will be clamped within valid range in the @return struct. jpayne@69: * This function never fails (wide contract) */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_CCtx_setCParams() : jpayne@69: * Set all parameters provided within @p cparams into the working @p cctx. jpayne@69: * Note : if modifying parameters during compression (MT mode only), jpayne@69: * note that changes to the .windowLog parameter will be ignored. jpayne@69: * @return 0 on success, or an error code (can be checked with ZSTD_isError()). jpayne@69: * On failure, no parameters are updated. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_setCParams(ZSTD_CCtx* cctx, ZSTD_compressionParameters cparams); jpayne@69: jpayne@69: /*! ZSTD_CCtx_setFParams() : jpayne@69: * Set all parameters provided within @p fparams into the working @p cctx. jpayne@69: * @return 0 on success, or an error code (can be checked with ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_setFParams(ZSTD_CCtx* cctx, ZSTD_frameParameters fparams); jpayne@69: jpayne@69: /*! ZSTD_CCtx_setParams() : jpayne@69: * Set all parameters provided within @p params into the working @p cctx. jpayne@69: * @return 0 on success, or an error code (can be checked with ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_setParams(ZSTD_CCtx* cctx, ZSTD_parameters params); jpayne@69: jpayne@69: /*! ZSTD_compress_advanced() : jpayne@69: * Note : this function is now DEPRECATED. jpayne@69: * It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_setParameter() and other parameter setters. jpayne@69: * This prototype will generate compilation warnings. */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_compress2") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_compress_advanced(ZSTD_CCtx* cctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: const void* dict,size_t dictSize, jpayne@69: ZSTD_parameters params); jpayne@69: jpayne@69: /*! ZSTD_compress_usingCDict_advanced() : jpayne@69: * Note : this function is now DEPRECATED. jpayne@69: * It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_loadDictionary() and other parameter setters. jpayne@69: * This prototype will generate compilation warnings. */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_compress2 with ZSTD_CCtx_loadDictionary") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx, jpayne@69: void* dst, size_t dstCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: const ZSTD_CDict* cdict, jpayne@69: ZSTD_frameParameters fParams); jpayne@69: jpayne@69: jpayne@69: /*! ZSTD_CCtx_loadDictionary_byReference() : jpayne@69: * Same as ZSTD_CCtx_loadDictionary(), but dictionary content is referenced, instead of being copied into CCtx. jpayne@69: * It saves some memory, but also requires that `dict` outlives its usage within `cctx` */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_CCtx_loadDictionary_advanced() : jpayne@69: * Same as ZSTD_CCtx_loadDictionary(), but gives finer control over jpayne@69: * how to load the dictionary (by copy ? by reference ?) jpayne@69: * and how to interpret it (automatic ? force raw mode ? full mode only ?) */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_loadDictionary_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); jpayne@69: jpayne@69: /*! ZSTD_CCtx_refPrefix_advanced() : jpayne@69: * Same as ZSTD_CCtx_refPrefix(), but gives finer control over jpayne@69: * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType); jpayne@69: jpayne@69: /* === experimental parameters === */ jpayne@69: /* these parameters can be used with ZSTD_setParameter() jpayne@69: * they are not guaranteed to remain supported in the future */ jpayne@69: jpayne@69: /* Enables rsyncable mode, jpayne@69: * which makes compressed files more rsync friendly jpayne@69: * by adding periodic synchronization points to the compressed data. jpayne@69: * The target average block size is ZSTD_c_jobSize / 2. jpayne@69: * It's possible to modify the job size to increase or decrease jpayne@69: * the granularity of the synchronization point. jpayne@69: * Once the jobSize is smaller than the window size, jpayne@69: * it will result in compression ratio degradation. jpayne@69: * NOTE 1: rsyncable mode only works when multithreading is enabled. jpayne@69: * NOTE 2: rsyncable performs poorly in combination with long range mode, jpayne@69: * since it will decrease the effectiveness of synchronization points, jpayne@69: * though mileage may vary. jpayne@69: * NOTE 3: Rsyncable mode limits maximum compression speed to ~400 MB/s. jpayne@69: * If the selected compression level is already running significantly slower, jpayne@69: * the overall speed won't be significantly impacted. jpayne@69: */ jpayne@69: #define ZSTD_c_rsyncable ZSTD_c_experimentalParam1 jpayne@69: jpayne@69: /* Select a compression format. jpayne@69: * The value must be of type ZSTD_format_e. jpayne@69: * See ZSTD_format_e enum definition for details */ jpayne@69: #define ZSTD_c_format ZSTD_c_experimentalParam2 jpayne@69: jpayne@69: /* Force back-reference distances to remain < windowSize, jpayne@69: * even when referencing into Dictionary content (default:0) */ jpayne@69: #define ZSTD_c_forceMaxWindow ZSTD_c_experimentalParam3 jpayne@69: jpayne@69: /* Controls whether the contents of a CDict jpayne@69: * are used in place, or copied into the working context. jpayne@69: * Accepts values from the ZSTD_dictAttachPref_e enum. jpayne@69: * See the comments on that enum for an explanation of the feature. */ jpayne@69: #define ZSTD_c_forceAttachDict ZSTD_c_experimentalParam4 jpayne@69: jpayne@69: /* Controlled with ZSTD_paramSwitch_e enum. jpayne@69: * Default is ZSTD_ps_auto. jpayne@69: * Set to ZSTD_ps_disable to never compress literals. jpayne@69: * Set to ZSTD_ps_enable to always compress literals. (Note: uncompressed literals jpayne@69: * may still be emitted if huffman is not beneficial to use.) jpayne@69: * jpayne@69: * By default, in ZSTD_ps_auto, the library will decide at runtime whether to use jpayne@69: * literals compression based on the compression parameters - specifically, jpayne@69: * negative compression levels do not use literal compression. jpayne@69: */ jpayne@69: #define ZSTD_c_literalCompressionMode ZSTD_c_experimentalParam5 jpayne@69: jpayne@69: /* User's best guess of source size. jpayne@69: * Hint is not valid when srcSizeHint == 0. jpayne@69: * There is no guarantee that hint is close to actual source size, jpayne@69: * but compression ratio may regress significantly if guess considerably underestimates */ jpayne@69: #define ZSTD_c_srcSizeHint ZSTD_c_experimentalParam7 jpayne@69: jpayne@69: /* Controls whether the new and experimental "dedicated dictionary search jpayne@69: * structure" can be used. This feature is still rough around the edges, be jpayne@69: * prepared for surprising behavior! jpayne@69: * jpayne@69: * How to use it: jpayne@69: * jpayne@69: * When using a CDict, whether to use this feature or not is controlled at jpayne@69: * CDict creation, and it must be set in a CCtxParams set passed into that jpayne@69: * construction (via ZSTD_createCDict_advanced2()). A compression will then jpayne@69: * use the feature or not based on how the CDict was constructed; the value of jpayne@69: * this param, set in the CCtx, will have no effect. jpayne@69: * jpayne@69: * However, when a dictionary buffer is passed into a CCtx, such as via jpayne@69: * ZSTD_CCtx_loadDictionary(), this param can be set on the CCtx to control jpayne@69: * whether the CDict that is created internally can use the feature or not. jpayne@69: * jpayne@69: * What it does: jpayne@69: * jpayne@69: * Normally, the internal data structures of the CDict are analogous to what jpayne@69: * would be stored in a CCtx after compressing the contents of a dictionary. jpayne@69: * To an approximation, a compression using a dictionary can then use those jpayne@69: * data structures to simply continue what is effectively a streaming jpayne@69: * compression where the simulated compression of the dictionary left off. jpayne@69: * Which is to say, the search structures in the CDict are normally the same jpayne@69: * format as in the CCtx. jpayne@69: * jpayne@69: * It is possible to do better, since the CDict is not like a CCtx: the search jpayne@69: * structures are written once during CDict creation, and then are only read jpayne@69: * after that, while the search structures in the CCtx are both read and jpayne@69: * written as the compression goes along. This means we can choose a search jpayne@69: * structure for the dictionary that is read-optimized. jpayne@69: * jpayne@69: * This feature enables the use of that different structure. jpayne@69: * jpayne@69: * Note that some of the members of the ZSTD_compressionParameters struct have jpayne@69: * different semantics and constraints in the dedicated search structure. It is jpayne@69: * highly recommended that you simply set a compression level in the CCtxParams jpayne@69: * you pass into the CDict creation call, and avoid messing with the cParams jpayne@69: * directly. jpayne@69: * jpayne@69: * Effects: jpayne@69: * jpayne@69: * This will only have any effect when the selected ZSTD_strategy jpayne@69: * implementation supports this feature. Currently, that's limited to jpayne@69: * ZSTD_greedy, ZSTD_lazy, and ZSTD_lazy2. jpayne@69: * jpayne@69: * Note that this means that the CDict tables can no longer be copied into the jpayne@69: * CCtx, so the dict attachment mode ZSTD_dictForceCopy will no longer be jpayne@69: * usable. The dictionary can only be attached or reloaded. jpayne@69: * jpayne@69: * In general, you should expect compression to be faster--sometimes very much jpayne@69: * so--and CDict creation to be slightly slower. Eventually, we will probably jpayne@69: * make this mode the default. jpayne@69: */ jpayne@69: #define ZSTD_c_enableDedicatedDictSearch ZSTD_c_experimentalParam8 jpayne@69: jpayne@69: /* ZSTD_c_stableInBuffer jpayne@69: * Experimental parameter. jpayne@69: * Default is 0 == disabled. Set to 1 to enable. jpayne@69: * jpayne@69: * Tells the compressor that input data presented with ZSTD_inBuffer jpayne@69: * will ALWAYS be the same between calls. jpayne@69: * Technically, the @src pointer must never be changed, jpayne@69: * and the @pos field can only be updated by zstd. jpayne@69: * However, it's possible to increase the @size field, jpayne@69: * allowing scenarios where more data can be appended after compressions starts. jpayne@69: * These conditions are checked by the compressor, jpayne@69: * and compression will fail if they are not respected. jpayne@69: * Also, data in the ZSTD_inBuffer within the range [src, src + pos) jpayne@69: * MUST not be modified during compression or it will result in data corruption. jpayne@69: * jpayne@69: * When this flag is enabled zstd won't allocate an input window buffer, jpayne@69: * because the user guarantees it can reference the ZSTD_inBuffer until jpayne@69: * the frame is complete. But, it will still allocate an output buffer jpayne@69: * large enough to fit a block (see ZSTD_c_stableOutBuffer). This will also jpayne@69: * avoid the memcpy() from the input buffer to the input window buffer. jpayne@69: * jpayne@69: * NOTE: So long as the ZSTD_inBuffer always points to valid memory, using jpayne@69: * this flag is ALWAYS memory safe, and will never access out-of-bounds jpayne@69: * memory. However, compression WILL fail if conditions are not respected. jpayne@69: * jpayne@69: * WARNING: The data in the ZSTD_inBuffer in the range [src, src + pos) MUST jpayne@69: * not be modified during compression or it will result in data corruption. jpayne@69: * This is because zstd needs to reference data in the ZSTD_inBuffer to find jpayne@69: * matches. Normally zstd maintains its own window buffer for this purpose, jpayne@69: * but passing this flag tells zstd to rely on user provided buffer instead. jpayne@69: */ jpayne@69: #define ZSTD_c_stableInBuffer ZSTD_c_experimentalParam9 jpayne@69: jpayne@69: /* ZSTD_c_stableOutBuffer jpayne@69: * Experimental parameter. jpayne@69: * Default is 0 == disabled. Set to 1 to enable. jpayne@69: * jpayne@69: * Tells he compressor that the ZSTD_outBuffer will not be resized between jpayne@69: * calls. Specifically: (out.size - out.pos) will never grow. This gives the jpayne@69: * compressor the freedom to say: If the compressed data doesn't fit in the jpayne@69: * output buffer then return ZSTD_error_dstSizeTooSmall. This allows us to jpayne@69: * always decompress directly into the output buffer, instead of decompressing jpayne@69: * into an internal buffer and copying to the output buffer. jpayne@69: * jpayne@69: * When this flag is enabled zstd won't allocate an output buffer, because jpayne@69: * it can write directly to the ZSTD_outBuffer. It will still allocate the jpayne@69: * input window buffer (see ZSTD_c_stableInBuffer). jpayne@69: * jpayne@69: * Zstd will check that (out.size - out.pos) never grows and return an error jpayne@69: * if it does. While not strictly necessary, this should prevent surprises. jpayne@69: */ jpayne@69: #define ZSTD_c_stableOutBuffer ZSTD_c_experimentalParam10 jpayne@69: jpayne@69: /* ZSTD_c_blockDelimiters jpayne@69: * Default is 0 == ZSTD_sf_noBlockDelimiters. jpayne@69: * jpayne@69: * For use with sequence compression API: ZSTD_compressSequences(). jpayne@69: * jpayne@69: * Designates whether or not the given array of ZSTD_Sequence contains block delimiters jpayne@69: * and last literals, which are defined as sequences with offset == 0 and matchLength == 0. jpayne@69: * See the definition of ZSTD_Sequence for more specifics. jpayne@69: */ jpayne@69: #define ZSTD_c_blockDelimiters ZSTD_c_experimentalParam11 jpayne@69: jpayne@69: /* ZSTD_c_validateSequences jpayne@69: * Default is 0 == disabled. Set to 1 to enable sequence validation. jpayne@69: * jpayne@69: * For use with sequence compression API: ZSTD_compressSequences(). jpayne@69: * Designates whether or not we validate sequences provided to ZSTD_compressSequences() jpayne@69: * during function execution. jpayne@69: * jpayne@69: * Without validation, providing a sequence that does not conform to the zstd spec will cause jpayne@69: * undefined behavior, and may produce a corrupted block. jpayne@69: * jpayne@69: * With validation enabled, if sequence is invalid (see doc/zstd_compression_format.md for jpayne@69: * specifics regarding offset/matchlength requirements) then the function will bail out and jpayne@69: * return an error. jpayne@69: * jpayne@69: */ jpayne@69: #define ZSTD_c_validateSequences ZSTD_c_experimentalParam12 jpayne@69: jpayne@69: /* ZSTD_c_useBlockSplitter jpayne@69: * Controlled with ZSTD_paramSwitch_e enum. jpayne@69: * Default is ZSTD_ps_auto. jpayne@69: * Set to ZSTD_ps_disable to never use block splitter. jpayne@69: * Set to ZSTD_ps_enable to always use block splitter. jpayne@69: * jpayne@69: * By default, in ZSTD_ps_auto, the library will decide at runtime whether to use jpayne@69: * block splitting based on the compression parameters. jpayne@69: */ jpayne@69: #define ZSTD_c_useBlockSplitter ZSTD_c_experimentalParam13 jpayne@69: jpayne@69: /* ZSTD_c_useRowMatchFinder jpayne@69: * Controlled with ZSTD_paramSwitch_e enum. jpayne@69: * Default is ZSTD_ps_auto. jpayne@69: * Set to ZSTD_ps_disable to never use row-based matchfinder. jpayne@69: * Set to ZSTD_ps_enable to force usage of row-based matchfinder. jpayne@69: * jpayne@69: * By default, in ZSTD_ps_auto, the library will decide at runtime whether to use jpayne@69: * the row-based matchfinder based on support for SIMD instructions and the window log. jpayne@69: * Note that this only pertains to compression strategies: greedy, lazy, and lazy2 jpayne@69: */ jpayne@69: #define ZSTD_c_useRowMatchFinder ZSTD_c_experimentalParam14 jpayne@69: jpayne@69: /* ZSTD_c_deterministicRefPrefix jpayne@69: * Default is 0 == disabled. Set to 1 to enable. jpayne@69: * jpayne@69: * Zstd produces different results for prefix compression when the prefix is jpayne@69: * directly adjacent to the data about to be compressed vs. when it isn't. jpayne@69: * This is because zstd detects that the two buffers are contiguous and it can jpayne@69: * use a more efficient match finding algorithm. However, this produces different jpayne@69: * results than when the two buffers are non-contiguous. This flag forces zstd jpayne@69: * to always load the prefix in non-contiguous mode, even if it happens to be jpayne@69: * adjacent to the data, to guarantee determinism. jpayne@69: * jpayne@69: * If you really care about determinism when using a dictionary or prefix, jpayne@69: * like when doing delta compression, you should select this option. It comes jpayne@69: * at a speed penalty of about ~2.5% if the dictionary and data happened to be jpayne@69: * contiguous, and is free if they weren't contiguous. We don't expect that jpayne@69: * intentionally making the dictionary and data contiguous will be worth the jpayne@69: * cost to memcpy() the data. jpayne@69: */ jpayne@69: #define ZSTD_c_deterministicRefPrefix ZSTD_c_experimentalParam15 jpayne@69: jpayne@69: /* ZSTD_c_prefetchCDictTables jpayne@69: * Controlled with ZSTD_paramSwitch_e enum. Default is ZSTD_ps_auto. jpayne@69: * jpayne@69: * In some situations, zstd uses CDict tables in-place rather than copying them jpayne@69: * into the working context. (See docs on ZSTD_dictAttachPref_e above for details). jpayne@69: * In such situations, compression speed is seriously impacted when CDict tables are jpayne@69: * "cold" (outside CPU cache). This parameter instructs zstd to prefetch CDict tables jpayne@69: * when they are used in-place. jpayne@69: * jpayne@69: * For sufficiently small inputs, the cost of the prefetch will outweigh the benefit. jpayne@69: * For sufficiently large inputs, zstd will by default memcpy() CDict tables jpayne@69: * into the working context, so there is no need to prefetch. This parameter is jpayne@69: * targeted at a middle range of input sizes, where a prefetch is cheap enough to be jpayne@69: * useful but memcpy() is too expensive. The exact range of input sizes where this jpayne@69: * makes sense is best determined by careful experimentation. jpayne@69: * jpayne@69: * Note: for this parameter, ZSTD_ps_auto is currently equivalent to ZSTD_ps_disable, jpayne@69: * but in the future zstd may conditionally enable this feature via an auto-detection jpayne@69: * heuristic for cold CDicts. jpayne@69: * Use ZSTD_ps_disable to opt out of prefetching under any circumstances. jpayne@69: */ jpayne@69: #define ZSTD_c_prefetchCDictTables ZSTD_c_experimentalParam16 jpayne@69: jpayne@69: /* ZSTD_c_enableSeqProducerFallback jpayne@69: * Allowed values are 0 (disable) and 1 (enable). The default setting is 0. jpayne@69: * jpayne@69: * Controls whether zstd will fall back to an internal sequence producer if an jpayne@69: * external sequence producer is registered and returns an error code. This fallback jpayne@69: * is block-by-block: the internal sequence producer will only be called for blocks jpayne@69: * where the external sequence producer returns an error code. Fallback parsing will jpayne@69: * follow any other cParam settings, such as compression level, the same as in a jpayne@69: * normal (fully-internal) compression operation. jpayne@69: * jpayne@69: * The user is strongly encouraged to read the full Block-Level Sequence Producer API jpayne@69: * documentation (below) before setting this parameter. */ jpayne@69: #define ZSTD_c_enableSeqProducerFallback ZSTD_c_experimentalParam17 jpayne@69: jpayne@69: /* ZSTD_c_maxBlockSize jpayne@69: * Allowed values are between 1KB and ZSTD_BLOCKSIZE_MAX (128KB). jpayne@69: * The default is ZSTD_BLOCKSIZE_MAX, and setting to 0 will set to the default. jpayne@69: * jpayne@69: * This parameter can be used to set an upper bound on the blocksize jpayne@69: * that overrides the default ZSTD_BLOCKSIZE_MAX. It cannot be used to set upper jpayne@69: * bounds greater than ZSTD_BLOCKSIZE_MAX or bounds lower than 1KB (will make jpayne@69: * compressBound() inaccurate). Only currently meant to be used for testing. jpayne@69: * jpayne@69: */ jpayne@69: #define ZSTD_c_maxBlockSize ZSTD_c_experimentalParam18 jpayne@69: jpayne@69: /* ZSTD_c_searchForExternalRepcodes jpayne@69: * This parameter affects how zstd parses external sequences, such as sequences jpayne@69: * provided through the compressSequences() API or from an external block-level jpayne@69: * sequence producer. jpayne@69: * jpayne@69: * If set to ZSTD_ps_enable, the library will check for repeated offsets in jpayne@69: * external sequences, even if those repcodes are not explicitly indicated in jpayne@69: * the "rep" field. Note that this is the only way to exploit repcode matches jpayne@69: * while using compressSequences() or an external sequence producer, since zstd jpayne@69: * currently ignores the "rep" field of external sequences. jpayne@69: * jpayne@69: * If set to ZSTD_ps_disable, the library will not exploit repeated offsets in jpayne@69: * external sequences, regardless of whether the "rep" field has been set. This jpayne@69: * reduces sequence compression overhead by about 25% while sacrificing some jpayne@69: * compression ratio. jpayne@69: * jpayne@69: * The default value is ZSTD_ps_auto, for which the library will enable/disable jpayne@69: * based on compression level. jpayne@69: * jpayne@69: * Note: for now, this param only has an effect if ZSTD_c_blockDelimiters is jpayne@69: * set to ZSTD_sf_explicitBlockDelimiters. That may change in the future. jpayne@69: */ jpayne@69: #define ZSTD_c_searchForExternalRepcodes ZSTD_c_experimentalParam19 jpayne@69: jpayne@69: /*! ZSTD_CCtx_getParameter() : jpayne@69: * Get the requested compression parameter value, selected by enum ZSTD_cParameter, jpayne@69: * and store it into int* value. jpayne@69: * @return : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_getParameter(const ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value); jpayne@69: jpayne@69: jpayne@69: /*! ZSTD_CCtx_params : jpayne@69: * Quick howto : jpayne@69: * - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure jpayne@69: * - ZSTD_CCtxParams_setParameter() : Push parameters one by one into jpayne@69: * an existing ZSTD_CCtx_params structure. jpayne@69: * This is similar to jpayne@69: * ZSTD_CCtx_setParameter(). jpayne@69: * - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to jpayne@69: * an existing CCtx. jpayne@69: * These parameters will be applied to jpayne@69: * all subsequent frames. jpayne@69: * - ZSTD_compressStream2() : Do compression using the CCtx. jpayne@69: * - ZSTD_freeCCtxParams() : Free the memory, accept NULL pointer. jpayne@69: * jpayne@69: * This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams() jpayne@69: * for static allocation of CCtx for single-threaded compression. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params); /* accept NULL pointer */ jpayne@69: jpayne@69: /*! ZSTD_CCtxParams_reset() : jpayne@69: * Reset params to default values. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_reset(ZSTD_CCtx_params* params); jpayne@69: jpayne@69: /*! ZSTD_CCtxParams_init() : jpayne@69: * Initializes the compression parameters of cctxParams according to jpayne@69: * compression level. All other parameters are reset to their default values. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel); jpayne@69: jpayne@69: /*! ZSTD_CCtxParams_init_advanced() : jpayne@69: * Initializes the compression and frame parameters of cctxParams according to jpayne@69: * params. All other parameters are reset to their default values. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params); jpayne@69: jpayne@69: /*! ZSTD_CCtxParams_setParameter() : Requires v1.4.0+ jpayne@69: * Similar to ZSTD_CCtx_setParameter. jpayne@69: * Set one compression parameter, selected by enum ZSTD_cParameter. jpayne@69: * Parameters must be applied to a ZSTD_CCtx using jpayne@69: * ZSTD_CCtx_setParametersUsingCCtxParams(). jpayne@69: * @result : a code representing success or failure (which can be tested with jpayne@69: * ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int value); jpayne@69: jpayne@69: /*! ZSTD_CCtxParams_getParameter() : jpayne@69: * Similar to ZSTD_CCtx_getParameter. jpayne@69: * Get the requested value of one compression parameter, selected by enum ZSTD_cParameter. jpayne@69: * @result : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_getParameter(const ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value); jpayne@69: jpayne@69: /*! ZSTD_CCtx_setParametersUsingCCtxParams() : jpayne@69: * Apply a set of ZSTD_CCtx_params to the compression context. jpayne@69: * This can be done even after compression is started, jpayne@69: * if nbWorkers==0, this will have no impact until a new compression is started. jpayne@69: * if nbWorkers>=1, new parameters will be picked up at next job, jpayne@69: * with a few restrictions (windowLog, pledgedSrcSize, nbWorkers, jobSize, and overlapLog are not updated). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_CCtx_setParametersUsingCCtxParams( jpayne@69: ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params); jpayne@69: jpayne@69: /*! ZSTD_compressStream2_simpleArgs() : jpayne@69: * Same as ZSTD_compressStream2(), jpayne@69: * but using only integral types as arguments. jpayne@69: * This variant might be helpful for binders from dynamic languages jpayne@69: * which have troubles handling structures containing memory pointers. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_compressStream2_simpleArgs ( jpayne@69: ZSTD_CCtx* cctx, jpayne@69: void* dst, size_t dstCapacity, size_t* dstPos, jpayne@69: const void* src, size_t srcSize, size_t* srcPos, jpayne@69: ZSTD_EndDirective endOp); jpayne@69: jpayne@69: jpayne@69: /*************************************** jpayne@69: * Advanced decompression functions jpayne@69: ***************************************/ jpayne@69: jpayne@69: /*! ZSTD_isFrame() : jpayne@69: * Tells if the content of `buffer` starts with a valid Frame Identifier. jpayne@69: * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0. jpayne@69: * Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled. jpayne@69: * Note 3 : Skippable Frame Identifiers are considered valid. */ jpayne@69: ZSTDLIB_STATIC_API unsigned ZSTD_isFrame(const void* buffer, size_t size); jpayne@69: jpayne@69: /*! ZSTD_createDDict_byReference() : jpayne@69: * Create a digested dictionary, ready to start decompression operation without startup delay. jpayne@69: * Dictionary content is referenced, and therefore stays in dictBuffer. jpayne@69: * It is important that dictBuffer outlives DDict, jpayne@69: * it must remain read accessible throughout the lifetime of DDict */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_DCtx_loadDictionary_byReference() : jpayne@69: * Same as ZSTD_DCtx_loadDictionary(), jpayne@69: * but references `dict` content instead of copying it into `dctx`. jpayne@69: * This saves memory if `dict` remains around., jpayne@69: * However, it's imperative that `dict` remains accessible (and unmodified) while being used, so it must outlive decompression. */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); jpayne@69: jpayne@69: /*! ZSTD_DCtx_loadDictionary_advanced() : jpayne@69: * Same as ZSTD_DCtx_loadDictionary(), jpayne@69: * but gives direct control over jpayne@69: * how to load the dictionary (by copy ? by reference ?) jpayne@69: * and how to interpret it (automatic ? force raw mode ? full mode only ?). */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); jpayne@69: jpayne@69: /*! ZSTD_DCtx_refPrefix_advanced() : jpayne@69: * Same as ZSTD_DCtx_refPrefix(), but gives finer control over jpayne@69: * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType); jpayne@69: jpayne@69: /*! ZSTD_DCtx_setMaxWindowSize() : jpayne@69: * Refuses allocating internal buffers for frames requiring a window size larger than provided limit. jpayne@69: * This protects a decoder context from reserving too much memory for itself (potential attack scenario). jpayne@69: * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. jpayne@69: * By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT) jpayne@69: * @return : 0, or an error code (which can be tested using ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize); jpayne@69: jpayne@69: /*! ZSTD_DCtx_getParameter() : jpayne@69: * Get the requested decompression parameter value, selected by enum ZSTD_dParameter, jpayne@69: * and store it into int* value. jpayne@69: * @return : 0, or an error code (which can be tested with ZSTD_isError()). jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_DCtx_getParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int* value); jpayne@69: jpayne@69: /* ZSTD_d_format jpayne@69: * experimental parameter, jpayne@69: * allowing selection between ZSTD_format_e input compression formats jpayne@69: */ jpayne@69: #define ZSTD_d_format ZSTD_d_experimentalParam1 jpayne@69: /* ZSTD_d_stableOutBuffer jpayne@69: * Experimental parameter. jpayne@69: * Default is 0 == disabled. Set to 1 to enable. jpayne@69: * jpayne@69: * Tells the decompressor that the ZSTD_outBuffer will ALWAYS be the same jpayne@69: * between calls, except for the modifications that zstd makes to pos (the jpayne@69: * caller must not modify pos). This is checked by the decompressor, and jpayne@69: * decompression will fail if it ever changes. Therefore the ZSTD_outBuffer jpayne@69: * MUST be large enough to fit the entire decompressed frame. This will be jpayne@69: * checked when the frame content size is known. The data in the ZSTD_outBuffer jpayne@69: * in the range [dst, dst + pos) MUST not be modified during decompression jpayne@69: * or you will get data corruption. jpayne@69: * jpayne@69: * When this flag is enabled zstd won't allocate an output buffer, because jpayne@69: * it can write directly to the ZSTD_outBuffer, but it will still allocate jpayne@69: * an input buffer large enough to fit any compressed block. This will also jpayne@69: * avoid the memcpy() from the internal output buffer to the ZSTD_outBuffer. jpayne@69: * If you need to avoid the input buffer allocation use the buffer-less jpayne@69: * streaming API. jpayne@69: * jpayne@69: * NOTE: So long as the ZSTD_outBuffer always points to valid memory, using jpayne@69: * this flag is ALWAYS memory safe, and will never access out-of-bounds jpayne@69: * memory. However, decompression WILL fail if you violate the preconditions. jpayne@69: * jpayne@69: * WARNING: The data in the ZSTD_outBuffer in the range [dst, dst + pos) MUST jpayne@69: * not be modified during decompression or you will get data corruption. This jpayne@69: * is because zstd needs to reference data in the ZSTD_outBuffer to regenerate jpayne@69: * matches. Normally zstd maintains its own buffer for this purpose, but passing jpayne@69: * this flag tells zstd to use the user provided buffer. jpayne@69: */ jpayne@69: #define ZSTD_d_stableOutBuffer ZSTD_d_experimentalParam2 jpayne@69: jpayne@69: /* ZSTD_d_forceIgnoreChecksum jpayne@69: * Experimental parameter. jpayne@69: * Default is 0 == disabled. Set to 1 to enable jpayne@69: * jpayne@69: * Tells the decompressor to skip checksum validation during decompression, regardless jpayne@69: * of whether checksumming was specified during compression. This offers some jpayne@69: * slight performance benefits, and may be useful for debugging. jpayne@69: * Param has values of type ZSTD_forceIgnoreChecksum_e jpayne@69: */ jpayne@69: #define ZSTD_d_forceIgnoreChecksum ZSTD_d_experimentalParam3 jpayne@69: jpayne@69: /* ZSTD_d_refMultipleDDicts jpayne@69: * Experimental parameter. jpayne@69: * Default is 0 == disabled. Set to 1 to enable jpayne@69: * jpayne@69: * If enabled and dctx is allocated on the heap, then additional memory will be allocated jpayne@69: * to store references to multiple ZSTD_DDict. That is, multiple calls of ZSTD_refDDict() jpayne@69: * using a given ZSTD_DCtx, rather than overwriting the previous DDict reference, will instead jpayne@69: * store all references. At decompression time, the appropriate dictID is selected jpayne@69: * from the set of DDicts based on the dictID in the frame. jpayne@69: * jpayne@69: * Usage is simply calling ZSTD_refDDict() on multiple dict buffers. jpayne@69: * jpayne@69: * Param has values of byte ZSTD_refMultipleDDicts_e jpayne@69: * jpayne@69: * WARNING: Enabling this parameter and calling ZSTD_DCtx_refDDict(), will trigger memory jpayne@69: * allocation for the hash table. ZSTD_freeDCtx() also frees this memory. jpayne@69: * Memory is allocated as per ZSTD_DCtx::customMem. jpayne@69: * jpayne@69: * Although this function allocates memory for the table, the user is still responsible for jpayne@69: * memory management of the underlying ZSTD_DDict* themselves. jpayne@69: */ jpayne@69: #define ZSTD_d_refMultipleDDicts ZSTD_d_experimentalParam4 jpayne@69: jpayne@69: /* ZSTD_d_disableHuffmanAssembly jpayne@69: * Set to 1 to disable the Huffman assembly implementation. jpayne@69: * The default value is 0, which allows zstd to use the Huffman assembly jpayne@69: * implementation if available. jpayne@69: * jpayne@69: * This parameter can be used to disable Huffman assembly at runtime. jpayne@69: * If you want to disable it at compile time you can define the macro jpayne@69: * ZSTD_DISABLE_ASM. jpayne@69: */ jpayne@69: #define ZSTD_d_disableHuffmanAssembly ZSTD_d_experimentalParam5 jpayne@69: jpayne@69: /* ZSTD_d_maxBlockSize jpayne@69: * Allowed values are between 1KB and ZSTD_BLOCKSIZE_MAX (128KB). jpayne@69: * The default is ZSTD_BLOCKSIZE_MAX, and setting to 0 will set to the default. jpayne@69: * jpayne@69: * Forces the decompressor to reject blocks whose content size is jpayne@69: * larger than the configured maxBlockSize. When maxBlockSize is jpayne@69: * larger than the windowSize, the windowSize is used instead. jpayne@69: * This saves memory on the decoder when you know all blocks are small. jpayne@69: * jpayne@69: * This option is typically used in conjunction with ZSTD_c_maxBlockSize. jpayne@69: * jpayne@69: * WARNING: This causes the decoder to reject otherwise valid frames jpayne@69: * that have block sizes larger than the configured maxBlockSize. jpayne@69: */ jpayne@69: #define ZSTD_d_maxBlockSize ZSTD_d_experimentalParam6 jpayne@69: jpayne@69: jpayne@69: /*! ZSTD_DCtx_setFormat() : jpayne@69: * This function is REDUNDANT. Prefer ZSTD_DCtx_setParameter(). jpayne@69: * Instruct the decoder context about what kind of data to decode next. jpayne@69: * This instruction is mandatory to decode data without a fully-formed header, jpayne@69: * such ZSTD_f_zstd1_magicless for example. jpayne@69: * @return : 0, or an error code (which can be tested using ZSTD_isError()). */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_DCtx_setParameter() instead") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format); jpayne@69: jpayne@69: /*! ZSTD_decompressStream_simpleArgs() : jpayne@69: * Same as ZSTD_decompressStream(), jpayne@69: * but using only integral types as arguments. jpayne@69: * This can be helpful for binders from dynamic languages jpayne@69: * which have troubles handling structures containing memory pointers. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_decompressStream_simpleArgs ( jpayne@69: ZSTD_DCtx* dctx, jpayne@69: void* dst, size_t dstCapacity, size_t* dstPos, jpayne@69: const void* src, size_t srcSize, size_t* srcPos); jpayne@69: jpayne@69: jpayne@69: /******************************************************************** jpayne@69: * Advanced streaming functions jpayne@69: * Warning : most of these functions are now redundant with the Advanced API. jpayne@69: * Once Advanced API reaches "stable" status, jpayne@69: * redundant functions will be deprecated, and then at some point removed. jpayne@69: ********************************************************************/ jpayne@69: jpayne@69: /*===== Advanced Streaming compression functions =====*/ jpayne@69: jpayne@69: /*! ZSTD_initCStream_srcSize() : jpayne@69: * This function is DEPRECATED, and equivalent to: jpayne@69: * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); jpayne@69: * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) jpayne@69: * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); jpayne@69: * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); jpayne@69: * jpayne@69: * pledgedSrcSize must be correct. If it is not known at init time, use jpayne@69: * ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs, jpayne@69: * "0" also disables frame content size field. It may be enabled in the future. jpayne@69: * This prototype will generate compilation warnings. jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, jpayne@69: int compressionLevel, jpayne@69: unsigned long long pledgedSrcSize); jpayne@69: jpayne@69: /*! ZSTD_initCStream_usingDict() : jpayne@69: * This function is DEPRECATED, and is equivalent to: jpayne@69: * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); jpayne@69: * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); jpayne@69: * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize); jpayne@69: * jpayne@69: * Creates of an internal CDict (incompatible with static CCtx), except if jpayne@69: * dict == NULL or dictSize < 8, in which case no dict is used. jpayne@69: * Note: dict is loaded with ZSTD_dct_auto (treated as a full zstd dictionary if jpayne@69: * it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy. jpayne@69: * This prototype will generate compilation warnings. jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, jpayne@69: const void* dict, size_t dictSize, jpayne@69: int compressionLevel); jpayne@69: jpayne@69: /*! ZSTD_initCStream_advanced() : jpayne@69: * This function is DEPRECATED, and is equivalent to: jpayne@69: * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); jpayne@69: * ZSTD_CCtx_setParams(zcs, params); jpayne@69: * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); jpayne@69: * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize); jpayne@69: * jpayne@69: * dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy. jpayne@69: * pledgedSrcSize must be correct. jpayne@69: * If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN. jpayne@69: * This prototype will generate compilation warnings. jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, jpayne@69: const void* dict, size_t dictSize, jpayne@69: ZSTD_parameters params, jpayne@69: unsigned long long pledgedSrcSize); jpayne@69: jpayne@69: /*! ZSTD_initCStream_usingCDict() : jpayne@69: * This function is DEPRECATED, and equivalent to: jpayne@69: * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); jpayne@69: * ZSTD_CCtx_refCDict(zcs, cdict); jpayne@69: * jpayne@69: * note : cdict will just be referenced, and must outlive compression session jpayne@69: * This prototype will generate compilation warnings. jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_CCtx_reset and ZSTD_CCtx_refCDict, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); jpayne@69: jpayne@69: /*! ZSTD_initCStream_usingCDict_advanced() : jpayne@69: * This function is DEPRECATED, and is equivalent to: jpayne@69: * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); jpayne@69: * ZSTD_CCtx_setFParams(zcs, fParams); jpayne@69: * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); jpayne@69: * ZSTD_CCtx_refCDict(zcs, cdict); jpayne@69: * jpayne@69: * same as ZSTD_initCStream_usingCDict(), with control over frame parameters. jpayne@69: * pledgedSrcSize must be correct. If srcSize is not known at init time, use jpayne@69: * value ZSTD_CONTENTSIZE_UNKNOWN. jpayne@69: * This prototype will generate compilation warnings. jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_CCtx_reset and ZSTD_CCtx_refCDict, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, jpayne@69: const ZSTD_CDict* cdict, jpayne@69: ZSTD_frameParameters fParams, jpayne@69: unsigned long long pledgedSrcSize); jpayne@69: jpayne@69: /*! ZSTD_resetCStream() : jpayne@69: * This function is DEPRECATED, and is equivalent to: jpayne@69: * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); jpayne@69: * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); jpayne@69: * Note: ZSTD_resetCStream() interprets pledgedSrcSize == 0 as ZSTD_CONTENTSIZE_UNKNOWN, but jpayne@69: * ZSTD_CCtx_setPledgedSrcSize() does not do the same, so ZSTD_CONTENTSIZE_UNKNOWN must be jpayne@69: * explicitly specified. jpayne@69: * jpayne@69: * start a new frame, using same parameters from previous frame. jpayne@69: * This is typically useful to skip dictionary loading stage, since it will reuse it in-place. jpayne@69: * Note that zcs must be init at least once before using ZSTD_resetCStream(). jpayne@69: * If pledgedSrcSize is not known at reset time, use macro ZSTD_CONTENTSIZE_UNKNOWN. jpayne@69: * If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end. jpayne@69: * For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs, jpayne@69: * but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead. jpayne@69: * @return : 0, or an error code (which can be tested using ZSTD_isError()) jpayne@69: * This prototype will generate compilation warnings. jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); jpayne@69: jpayne@69: jpayne@69: typedef struct { jpayne@69: unsigned long long ingested; /* nb input bytes read and buffered */ jpayne@69: unsigned long long consumed; /* nb input bytes actually compressed */ jpayne@69: unsigned long long produced; /* nb of compressed bytes generated and buffered */ jpayne@69: unsigned long long flushed; /* nb of compressed bytes flushed : not provided; can be tracked from caller side */ jpayne@69: unsigned currentJobID; /* MT only : latest started job nb */ jpayne@69: unsigned nbActiveWorkers; /* MT only : nb of workers actively compressing at probe time */ jpayne@69: } ZSTD_frameProgression; jpayne@69: jpayne@69: /* ZSTD_getFrameProgression() : jpayne@69: * tells how much data has been ingested (read from input) jpayne@69: * consumed (input actually compressed) and produced (output) for current frame. jpayne@69: * Note : (ingested - consumed) is amount of input data buffered internally, not yet compressed. jpayne@69: * Aggregates progression inside active worker threads. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx* cctx); jpayne@69: jpayne@69: /*! ZSTD_toFlushNow() : jpayne@69: * Tell how many bytes are ready to be flushed immediately. jpayne@69: * Useful for multithreading scenarios (nbWorkers >= 1). jpayne@69: * Probe the oldest active job, defined as oldest job not yet entirely flushed, jpayne@69: * and check its output buffer. jpayne@69: * @return : amount of data stored in oldest job and ready to be flushed immediately. jpayne@69: * if @return == 0, it means either : jpayne@69: * + there is no active job (could be checked with ZSTD_frameProgression()), or jpayne@69: * + oldest job is still actively compressing data, jpayne@69: * but everything it has produced has also been flushed so far, jpayne@69: * therefore flush speed is limited by production speed of oldest job jpayne@69: * irrespective of the speed of concurrent (and newer) jobs. jpayne@69: */ jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx); jpayne@69: jpayne@69: jpayne@69: /*===== Advanced Streaming decompression functions =====*/ jpayne@69: jpayne@69: /*! jpayne@69: * This function is deprecated, and is equivalent to: jpayne@69: * jpayne@69: * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); jpayne@69: * ZSTD_DCtx_loadDictionary(zds, dict, dictSize); jpayne@69: * jpayne@69: * note: no dictionary will be used if dict == NULL or dictSize < 8 jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_DCtx_reset + ZSTD_DCtx_loadDictionary, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); jpayne@69: jpayne@69: /*! jpayne@69: * This function is deprecated, and is equivalent to: jpayne@69: * jpayne@69: * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); jpayne@69: * ZSTD_DCtx_refDDict(zds, ddict); jpayne@69: * jpayne@69: * note : ddict is referenced, it must outlive decompression session jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_DCtx_reset + ZSTD_DCtx_refDDict, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); jpayne@69: jpayne@69: /*! jpayne@69: * This function is deprecated, and is equivalent to: jpayne@69: * jpayne@69: * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); jpayne@69: * jpayne@69: * reuse decompression parameters from previous init; saves dictionary loading jpayne@69: */ jpayne@69: ZSTD_DEPRECATED("use ZSTD_DCtx_reset, see zstd.h for detailed instructions") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); jpayne@69: jpayne@69: jpayne@69: /* ********************* BLOCK-LEVEL SEQUENCE PRODUCER API ********************* jpayne@69: * jpayne@69: * *** OVERVIEW *** jpayne@69: * The Block-Level Sequence Producer API allows users to provide their own custom jpayne@69: * sequence producer which libzstd invokes to process each block. The produced list jpayne@69: * of sequences (literals and matches) is then post-processed by libzstd to produce jpayne@69: * valid compressed blocks. jpayne@69: * jpayne@69: * This block-level offload API is a more granular complement of the existing jpayne@69: * frame-level offload API compressSequences() (introduced in v1.5.1). It offers jpayne@69: * an easier migration story for applications already integrated with libzstd: the jpayne@69: * user application continues to invoke the same compression functions jpayne@69: * ZSTD_compress2() or ZSTD_compressStream2() as usual, and transparently benefits jpayne@69: * from the specific advantages of the external sequence producer. For example, jpayne@69: * the sequence producer could be tuned to take advantage of known characteristics jpayne@69: * of the input, to offer better speed / ratio, or could leverage hardware jpayne@69: * acceleration not available within libzstd itself. jpayne@69: * jpayne@69: * See contrib/externalSequenceProducer for an example program employing the jpayne@69: * Block-Level Sequence Producer API. jpayne@69: * jpayne@69: * *** USAGE *** jpayne@69: * The user is responsible for implementing a function of type jpayne@69: * ZSTD_sequenceProducer_F. For each block, zstd will pass the following jpayne@69: * arguments to the user-provided function: jpayne@69: * jpayne@69: * - sequenceProducerState: a pointer to a user-managed state for the sequence jpayne@69: * producer. jpayne@69: * jpayne@69: * - outSeqs, outSeqsCapacity: an output buffer for the sequence producer. jpayne@69: * outSeqsCapacity is guaranteed >= ZSTD_sequenceBound(srcSize). The memory jpayne@69: * backing outSeqs is managed by the CCtx. jpayne@69: * jpayne@69: * - src, srcSize: an input buffer for the sequence producer to parse. jpayne@69: * srcSize is guaranteed to be <= ZSTD_BLOCKSIZE_MAX. jpayne@69: * jpayne@69: * - dict, dictSize: a history buffer, which may be empty, which the sequence jpayne@69: * producer may reference as it parses the src buffer. Currently, zstd will jpayne@69: * always pass dictSize == 0 into external sequence producers, but this will jpayne@69: * change in the future. jpayne@69: * jpayne@69: * - compressionLevel: a signed integer representing the zstd compression level jpayne@69: * set by the user for the current operation. The sequence producer may choose jpayne@69: * to use this information to change its compression strategy and speed/ratio jpayne@69: * tradeoff. Note: the compression level does not reflect zstd parameters set jpayne@69: * through the advanced API. jpayne@69: * jpayne@69: * - windowSize: a size_t representing the maximum allowed offset for external jpayne@69: * sequences. Note that sequence offsets are sometimes allowed to exceed the jpayne@69: * windowSize if a dictionary is present, see doc/zstd_compression_format.md jpayne@69: * for details. jpayne@69: * jpayne@69: * The user-provided function shall return a size_t representing the number of jpayne@69: * sequences written to outSeqs. This return value will be treated as an error jpayne@69: * code if it is greater than outSeqsCapacity. The return value must be non-zero jpayne@69: * if srcSize is non-zero. The ZSTD_SEQUENCE_PRODUCER_ERROR macro is provided jpayne@69: * for convenience, but any value greater than outSeqsCapacity will be treated as jpayne@69: * an error code. jpayne@69: * jpayne@69: * If the user-provided function does not return an error code, the sequences jpayne@69: * written to outSeqs must be a valid parse of the src buffer. Data corruption may jpayne@69: * occur if the parse is not valid. A parse is defined to be valid if the jpayne@69: * following conditions hold: jpayne@69: * - The sum of matchLengths and literalLengths must equal srcSize. jpayne@69: * - All sequences in the parse, except for the final sequence, must have jpayne@69: * matchLength >= ZSTD_MINMATCH_MIN. The final sequence must have jpayne@69: * matchLength >= ZSTD_MINMATCH_MIN or matchLength == 0. jpayne@69: * - All offsets must respect the windowSize parameter as specified in jpayne@69: * doc/zstd_compression_format.md. jpayne@69: * - If the final sequence has matchLength == 0, it must also have offset == 0. jpayne@69: * jpayne@69: * zstd will only validate these conditions (and fail compression if they do not jpayne@69: * hold) if the ZSTD_c_validateSequences cParam is enabled. Note that sequence jpayne@69: * validation has a performance cost. jpayne@69: * jpayne@69: * If the user-provided function returns an error, zstd will either fall back jpayne@69: * to an internal sequence producer or fail the compression operation. The user can jpayne@69: * choose between the two behaviors by setting the ZSTD_c_enableSeqProducerFallback jpayne@69: * cParam. Fallback compression will follow any other cParam settings, such as jpayne@69: * compression level, the same as in a normal compression operation. jpayne@69: * jpayne@69: * The user shall instruct zstd to use a particular ZSTD_sequenceProducer_F jpayne@69: * function by calling jpayne@69: * ZSTD_registerSequenceProducer(cctx, jpayne@69: * sequenceProducerState, jpayne@69: * sequenceProducer) jpayne@69: * This setting will persist until the next parameter reset of the CCtx. jpayne@69: * jpayne@69: * The sequenceProducerState must be initialized by the user before calling jpayne@69: * ZSTD_registerSequenceProducer(). The user is responsible for destroying the jpayne@69: * sequenceProducerState. jpayne@69: * jpayne@69: * *** LIMITATIONS *** jpayne@69: * This API is compatible with all zstd compression APIs which respect advanced parameters. jpayne@69: * However, there are three limitations: jpayne@69: * jpayne@69: * First, the ZSTD_c_enableLongDistanceMatching cParam is not currently supported. jpayne@69: * COMPRESSION WILL FAIL if it is enabled and the user tries to compress with a block-level jpayne@69: * external sequence producer. jpayne@69: * - Note that ZSTD_c_enableLongDistanceMatching is auto-enabled by default in some jpayne@69: * cases (see its documentation for details). Users must explicitly set jpayne@69: * ZSTD_c_enableLongDistanceMatching to ZSTD_ps_disable in such cases if an external jpayne@69: * sequence producer is registered. jpayne@69: * - As of this writing, ZSTD_c_enableLongDistanceMatching is disabled by default jpayne@69: * whenever ZSTD_c_windowLog < 128MB, but that's subject to change. Users should jpayne@69: * check the docs on ZSTD_c_enableLongDistanceMatching whenever the Block-Level Sequence jpayne@69: * Producer API is used in conjunction with advanced settings (like ZSTD_c_windowLog). jpayne@69: * jpayne@69: * Second, history buffers are not currently supported. Concretely, zstd will always pass jpayne@69: * dictSize == 0 to the external sequence producer (for now). This has two implications: jpayne@69: * - Dictionaries are not currently supported. Compression will *not* fail if the user jpayne@69: * references a dictionary, but the dictionary won't have any effect. jpayne@69: * - Stream history is not currently supported. All advanced compression APIs, including jpayne@69: * streaming APIs, work with external sequence producers, but each block is treated as jpayne@69: * an independent chunk without history from previous blocks. jpayne@69: * jpayne@69: * Third, multi-threading within a single compression is not currently supported. In other words, jpayne@69: * COMPRESSION WILL FAIL if ZSTD_c_nbWorkers > 0 and an external sequence producer is registered. jpayne@69: * Multi-threading across compressions is fine: simply create one CCtx per thread. jpayne@69: * jpayne@69: * Long-term, we plan to overcome all three limitations. There is no technical blocker to jpayne@69: * overcoming them. It is purely a question of engineering effort. jpayne@69: */ jpayne@69: jpayne@69: #define ZSTD_SEQUENCE_PRODUCER_ERROR ((size_t)(-1)) jpayne@69: jpayne@69: typedef size_t (*ZSTD_sequenceProducer_F) ( jpayne@69: void* sequenceProducerState, jpayne@69: ZSTD_Sequence* outSeqs, size_t outSeqsCapacity, jpayne@69: const void* src, size_t srcSize, jpayne@69: const void* dict, size_t dictSize, jpayne@69: int compressionLevel, jpayne@69: size_t windowSize jpayne@69: ); jpayne@69: jpayne@69: /*! ZSTD_registerSequenceProducer() : jpayne@69: * Instruct zstd to use a block-level external sequence producer function. jpayne@69: * jpayne@69: * The sequenceProducerState must be initialized by the caller, and the caller is jpayne@69: * responsible for managing its lifetime. This parameter is sticky across jpayne@69: * compressions. It will remain set until the user explicitly resets compression jpayne@69: * parameters. jpayne@69: * jpayne@69: * Sequence producer registration is considered to be an "advanced parameter", jpayne@69: * part of the "advanced API". This means it will only have an effect on compression jpayne@69: * APIs which respect advanced parameters, such as compress2() and compressStream2(). jpayne@69: * Older compression APIs such as compressCCtx(), which predate the introduction of jpayne@69: * "advanced parameters", will ignore any external sequence producer setting. jpayne@69: * jpayne@69: * The sequence producer can be "cleared" by registering a NULL function pointer. This jpayne@69: * removes all limitations described above in the "LIMITATIONS" section of the API docs. jpayne@69: * jpayne@69: * The user is strongly encouraged to read the full API documentation (above) before jpayne@69: * calling this function. */ jpayne@69: ZSTDLIB_STATIC_API void jpayne@69: ZSTD_registerSequenceProducer( jpayne@69: ZSTD_CCtx* cctx, jpayne@69: void* sequenceProducerState, jpayne@69: ZSTD_sequenceProducer_F sequenceProducer jpayne@69: ); jpayne@69: jpayne@69: /*! ZSTD_CCtxParams_registerSequenceProducer() : jpayne@69: * Same as ZSTD_registerSequenceProducer(), but operates on ZSTD_CCtx_params. jpayne@69: * This is used for accurate size estimation with ZSTD_estimateCCtxSize_usingCCtxParams(), jpayne@69: * which is needed when creating a ZSTD_CCtx with ZSTD_initStaticCCtx(). jpayne@69: * jpayne@69: * If you are using the external sequence producer API in a scenario where ZSTD_initStaticCCtx() jpayne@69: * is required, then this function is for you. Otherwise, you probably don't need it. jpayne@69: * jpayne@69: * See tests/zstreamtest.c for example usage. */ jpayne@69: ZSTDLIB_STATIC_API void jpayne@69: ZSTD_CCtxParams_registerSequenceProducer( jpayne@69: ZSTD_CCtx_params* params, jpayne@69: void* sequenceProducerState, jpayne@69: ZSTD_sequenceProducer_F sequenceProducer jpayne@69: ); jpayne@69: jpayne@69: jpayne@69: /********************************************************************* jpayne@69: * Buffer-less and synchronous inner streaming functions (DEPRECATED) jpayne@69: * jpayne@69: * This API is deprecated, and will be removed in a future version. jpayne@69: * It allows streaming (de)compression with user allocated buffers. jpayne@69: * However, it is hard to use, and not as well tested as the rest of jpayne@69: * our API. jpayne@69: * jpayne@69: * Please use the normal streaming API instead: ZSTD_compressStream2, jpayne@69: * and ZSTD_decompressStream. jpayne@69: * If there is functionality that you need, but it doesn't provide, jpayne@69: * please open an issue on our GitHub. jpayne@69: ********************************************************************* */ jpayne@69: jpayne@69: /** jpayne@69: Buffer-less streaming compression (synchronous mode) jpayne@69: jpayne@69: A ZSTD_CCtx object is required to track streaming operations. jpayne@69: Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource. jpayne@69: ZSTD_CCtx object can be reused multiple times within successive compression operations. jpayne@69: jpayne@69: Start by initializing a context. jpayne@69: Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression. jpayne@69: jpayne@69: Then, consume your input using ZSTD_compressContinue(). jpayne@69: There are some important considerations to keep in mind when using this advanced function : jpayne@69: - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only. jpayne@69: - Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks. jpayne@69: - Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario. jpayne@69: Worst case evaluation is provided by ZSTD_compressBound(). jpayne@69: ZSTD_compressContinue() doesn't guarantee recover after a failed compression. jpayne@69: - ZSTD_compressContinue() presumes prior input ***is still accessible and unmodified*** (up to maximum distance size, see WindowLog). jpayne@69: It remembers all previous contiguous blocks, plus one separated memory segment (which can itself consists of multiple contiguous blocks) jpayne@69: - ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps. jpayne@69: In which case, it will "discard" the relevant memory section from its history. jpayne@69: jpayne@69: Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum. jpayne@69: It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame. jpayne@69: Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders. jpayne@69: jpayne@69: `ZSTD_CCtx` object can be reused (ZSTD_compressBegin()) to compress again. jpayne@69: */ jpayne@69: jpayne@69: /*===== Buffer-less streaming compression functions =====*/ jpayne@69: ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel); jpayne@69: ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel); jpayne@69: ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /**< note: fails if cdict==NULL */ jpayne@69: jpayne@69: ZSTD_DEPRECATED("This function will likely be removed in a future release. It is misleading and has very limited utility.") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); /**< note: if pledgedSrcSize is not known, use ZSTD_CONTENTSIZE_UNKNOWN */ jpayne@69: jpayne@69: ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); jpayne@69: ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); jpayne@69: jpayne@69: /* The ZSTD_compressBegin_advanced() and ZSTD_compressBegin_usingCDict_advanced() are now DEPRECATED and will generate a compiler warning */ jpayne@69: ZSTD_DEPRECATED("use advanced API to access custom parameters") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize : If srcSize is not known at init time, use ZSTD_CONTENTSIZE_UNKNOWN */ jpayne@69: ZSTD_DEPRECATED("use advanced API to access custom parameters") jpayne@69: ZSTDLIB_STATIC_API jpayne@69: size_t ZSTD_compressBegin_usingCDict_advanced(ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict, ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize); /* compression parameters are already set within cdict. pledgedSrcSize must be correct. If srcSize is not known, use macro ZSTD_CONTENTSIZE_UNKNOWN */ jpayne@69: /** jpayne@69: Buffer-less streaming decompression (synchronous mode) jpayne@69: jpayne@69: A ZSTD_DCtx object is required to track streaming operations. jpayne@69: Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it. jpayne@69: A ZSTD_DCtx object can be reused multiple times. jpayne@69: jpayne@69: First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader(). jpayne@69: Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough. jpayne@69: Data fragment must be large enough to ensure successful decoding. jpayne@69: `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough. jpayne@69: result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled. jpayne@69: >0 : `srcSize` is too small, please provide at least result bytes on next attempt. jpayne@69: errorCode, which can be tested using ZSTD_isError(). jpayne@69: jpayne@69: It fills a ZSTD_frameHeader structure with important information to correctly decode the frame, jpayne@69: such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`). jpayne@69: Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information. jpayne@69: As a consequence, check that values remain within valid application range. jpayne@69: For example, do not allocate memory blindly, check that `windowSize` is within expectation. jpayne@69: Each application can set its own limits, depending on local restrictions. jpayne@69: For extended interoperability, it is recommended to support `windowSize` of at least 8 MB. jpayne@69: jpayne@69: ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes. jpayne@69: ZSTD_decompressContinue() is very sensitive to contiguity, jpayne@69: if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place, jpayne@69: or that previous contiguous segment is large enough to properly handle maximum back-reference distance. jpayne@69: There are multiple ways to guarantee this condition. jpayne@69: jpayne@69: The most memory efficient way is to use a round buffer of sufficient size. jpayne@69: Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(), jpayne@69: which can return an error code if required value is too large for current system (in 32-bits mode). jpayne@69: In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one, jpayne@69: up to the moment there is not enough room left in the buffer to guarantee decoding another full block, jpayne@69: which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`. jpayne@69: At which point, decoding can resume from the beginning of the buffer. jpayne@69: Note that already decoded data stored in the buffer should be flushed before being overwritten. jpayne@69: jpayne@69: There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory. jpayne@69: jpayne@69: Finally, if you control the compression process, you can also ignore all buffer size rules, jpayne@69: as long as the encoder and decoder progress in "lock-step", jpayne@69: aka use exactly the same buffer sizes, break contiguity at the same place, etc. jpayne@69: jpayne@69: Once buffers are setup, start decompression, with ZSTD_decompressBegin(). jpayne@69: If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict(). jpayne@69: jpayne@69: Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively. jpayne@69: ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue(). jpayne@69: ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail. jpayne@69: jpayne@69: result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity). jpayne@69: It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item. jpayne@69: It can also be an error code, which can be tested with ZSTD_isError(). jpayne@69: jpayne@69: A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero. jpayne@69: Context can then be reset to start a new decompression. jpayne@69: jpayne@69: Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType(). jpayne@69: This information is not required to properly decode a frame. jpayne@69: jpayne@69: == Special case : skippable frames == jpayne@69: jpayne@69: Skippable frames allow integration of user-defined data into a flow of concatenated frames. jpayne@69: Skippable frames will be ignored (skipped) by decompressor. jpayne@69: The format of skippable frames is as follows : jpayne@69: a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F jpayne@69: b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits jpayne@69: c) Frame Content - any content (User Data) of length equal to Frame Size jpayne@69: For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame. jpayne@69: For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content. jpayne@69: */ jpayne@69: jpayne@69: /*===== Buffer-less streaming decompression functions =====*/ jpayne@69: jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize); /**< when frame content size is not known, pass in frameContentSize == ZSTD_CONTENTSIZE_UNKNOWN */ jpayne@69: jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); jpayne@69: jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx); jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); jpayne@69: jpayne@69: /* misc */ jpayne@69: ZSTD_DEPRECATED("This function will likely be removed in the next minor release. It is misleading and has very limited utility.") jpayne@69: ZSTDLIB_STATIC_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx); jpayne@69: typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e; jpayne@69: ZSTDLIB_STATIC_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx); jpayne@69: jpayne@69: jpayne@69: jpayne@69: jpayne@69: /* ========================================= */ jpayne@69: /** Block level API (DEPRECATED) */ jpayne@69: /* ========================================= */ jpayne@69: jpayne@69: /*! jpayne@69: jpayne@69: This API is deprecated in favor of the regular compression API. jpayne@69: You can get the frame header down to 2 bytes by setting: jpayne@69: - ZSTD_c_format = ZSTD_f_zstd1_magicless jpayne@69: - ZSTD_c_contentSizeFlag = 0 jpayne@69: - ZSTD_c_checksumFlag = 0 jpayne@69: - ZSTD_c_dictIDFlag = 0 jpayne@69: jpayne@69: This API is not as well tested as our normal API, so we recommend not using it. jpayne@69: We will be removing it in a future version. If the normal API doesn't provide jpayne@69: the functionality you need, please open a GitHub issue. jpayne@69: jpayne@69: Block functions produce and decode raw zstd blocks, without frame metadata. jpayne@69: Frame metadata cost is typically ~12 bytes, which can be non-negligible for very small blocks (< 100 bytes). jpayne@69: But users will have to take in charge needed metadata to regenerate data, such as compressed and content sizes. jpayne@69: jpayne@69: A few rules to respect : jpayne@69: - Compressing and decompressing require a context structure jpayne@69: + Use ZSTD_createCCtx() and ZSTD_createDCtx() jpayne@69: - It is necessary to init context before starting jpayne@69: + compression : any ZSTD_compressBegin*() variant, including with dictionary jpayne@69: + decompression : any ZSTD_decompressBegin*() variant, including with dictionary jpayne@69: - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB jpayne@69: + If input is larger than a block size, it's necessary to split input data into multiple blocks jpayne@69: + For inputs larger than a single block, consider using regular ZSTD_compress() instead. jpayne@69: Frame metadata is not that costly, and quickly becomes negligible as source size grows larger than a block. jpayne@69: - When a block is considered not compressible enough, ZSTD_compressBlock() result will be 0 (zero) ! jpayne@69: ===> In which case, nothing is produced into `dst` ! jpayne@69: + User __must__ test for such outcome and deal directly with uncompressed data jpayne@69: + A block cannot be declared incompressible if ZSTD_compressBlock() return value was != 0. jpayne@69: Doing so would mess up with statistics history, leading to potential data corruption. jpayne@69: + ZSTD_decompressBlock() _doesn't accept uncompressed data as input_ !! jpayne@69: + In case of multiple successive blocks, should some of them be uncompressed, jpayne@69: decoder must be informed of their existence in order to follow proper history. jpayne@69: Use ZSTD_insertBlock() for such a case. jpayne@69: */ jpayne@69: jpayne@69: /*===== Raw zstd block functions =====*/ jpayne@69: ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx); jpayne@69: ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); jpayne@69: ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); jpayne@69: ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.") jpayne@69: ZSTDLIB_STATIC_API size_t ZSTD_insertBlock (ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /**< insert uncompressed block into `dctx` history. Useful for multi-blocks decompression. */ jpayne@69: jpayne@69: #endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */ jpayne@69: jpayne@69: #if defined (__cplusplus) jpayne@69: } jpayne@69: #endif