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annotate CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/include/unicode/stringpiece.h @ 69:33d812a61356

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planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author jpayne
date Tue, 18 Mar 2025 17:55:14 -0400
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jpayne@69 1 // © 2016 and later: Unicode, Inc. and others.
jpayne@69 2 // License & terms of use: http://www.unicode.org/copyright.html
jpayne@69 3 // Copyright (C) 2009-2013, International Business Machines
jpayne@69 4 // Corporation and others. All Rights Reserved.
jpayne@69 5 //
jpayne@69 6 // Copyright 2001 and onwards Google Inc.
jpayne@69 7 // Author: Sanjay Ghemawat
jpayne@69 8
jpayne@69 9 // This code is a contribution of Google code, and the style used here is
jpayne@69 10 // a compromise between the original Google code and the ICU coding guidelines.
jpayne@69 11 // For example, data types are ICU-ified (size_t,int->int32_t),
jpayne@69 12 // and API comments doxygen-ified, but function names and behavior are
jpayne@69 13 // as in the original, if possible.
jpayne@69 14 // Assertion-style error handling, not available in ICU, was changed to
jpayne@69 15 // parameter "pinning" similar to UnicodeString.
jpayne@69 16 //
jpayne@69 17 // In addition, this is only a partial port of the original Google code,
jpayne@69 18 // limited to what was needed so far. The (nearly) complete original code
jpayne@69 19 // is in the ICU svn repository at icuhtml/trunk/design/strings/contrib
jpayne@69 20 // (see ICU ticket 6765, r25517).
jpayne@69 21
jpayne@69 22 #ifndef __STRINGPIECE_H__
jpayne@69 23 #define __STRINGPIECE_H__
jpayne@69 24
jpayne@69 25 /**
jpayne@69 26 * \file
jpayne@69 27 * \brief C++ API: StringPiece: Read-only byte string wrapper class.
jpayne@69 28 */
jpayne@69 29
jpayne@69 30 #include "unicode/utypes.h"
jpayne@69 31
jpayne@69 32 #if U_SHOW_CPLUSPLUS_API
jpayne@69 33
jpayne@69 34 #include <cstddef>
jpayne@69 35 #include <type_traits>
jpayne@69 36
jpayne@69 37 #include "unicode/uobject.h"
jpayne@69 38 #include "unicode/std_string.h"
jpayne@69 39
jpayne@69 40 // Arghh! I wish C++ literals were "string".
jpayne@69 41
jpayne@69 42 U_NAMESPACE_BEGIN
jpayne@69 43
jpayne@69 44 /**
jpayne@69 45 * A string-like object that points to a sized piece of memory.
jpayne@69 46 *
jpayne@69 47 * We provide non-explicit singleton constructors so users can pass
jpayne@69 48 * in a "const char*" or a "string" wherever a "StringPiece" is
jpayne@69 49 * expected.
jpayne@69 50 *
jpayne@69 51 * Functions or methods may use StringPiece parameters to accept either a
jpayne@69 52 * "const char*" or a "string" value that will be implicitly converted to a
jpayne@69 53 * StringPiece.
jpayne@69 54 *
jpayne@69 55 * Systematic usage of StringPiece is encouraged as it will reduce unnecessary
jpayne@69 56 * conversions from "const char*" to "string" and back again.
jpayne@69 57 *
jpayne@69 58 * @stable ICU 4.2
jpayne@69 59 */
jpayne@69 60 class U_COMMON_API StringPiece : public UMemory {
jpayne@69 61 private:
jpayne@69 62 const char* ptr_;
jpayne@69 63 int32_t length_;
jpayne@69 64
jpayne@69 65 public:
jpayne@69 66 /**
jpayne@69 67 * Default constructor, creates an empty StringPiece.
jpayne@69 68 * @stable ICU 4.2
jpayne@69 69 */
jpayne@69 70 StringPiece() : ptr_(nullptr), length_(0) { }
jpayne@69 71
jpayne@69 72 /**
jpayne@69 73 * Constructs from a NUL-terminated const char * pointer.
jpayne@69 74 * @param str a NUL-terminated const char * pointer
jpayne@69 75 * @stable ICU 4.2
jpayne@69 76 */
jpayne@69 77 StringPiece(const char* str);
jpayne@69 78 #ifndef U_HIDE_DRAFT_API
jpayne@69 79 #if defined(__cpp_char8_t) || defined(U_IN_DOXYGEN)
jpayne@69 80 /**
jpayne@69 81 * Constructs from a NUL-terminated const char8_t * pointer.
jpayne@69 82 * @param str a NUL-terminated const char8_t * pointer
jpayne@69 83 * @draft ICU 67
jpayne@69 84 */
jpayne@69 85 StringPiece(const char8_t* str) : StringPiece(reinterpret_cast<const char*>(str)) {}
jpayne@69 86 #endif
jpayne@69 87 /**
jpayne@69 88 * Constructs an empty StringPiece.
jpayne@69 89 * Needed for type disambiguation from multiple other overloads.
jpayne@69 90 * @param p nullptr
jpayne@69 91 * @draft ICU 67
jpayne@69 92 */
jpayne@69 93 StringPiece(std::nullptr_t p) : ptr_(p), length_(0) {}
jpayne@69 94 #endif // U_HIDE_DRAFT_API
jpayne@69 95
jpayne@69 96 /**
jpayne@69 97 * Constructs from a std::string.
jpayne@69 98 * @stable ICU 4.2
jpayne@69 99 */
jpayne@69 100 StringPiece(const std::string& str)
jpayne@69 101 : ptr_(str.data()), length_(static_cast<int32_t>(str.size())) { }
jpayne@69 102 #ifndef U_HIDE_DRAFT_API
jpayne@69 103 #if defined(__cpp_lib_char8_t) || defined(U_IN_DOXYGEN)
jpayne@69 104 /**
jpayne@69 105 * Constructs from a std::u8string.
jpayne@69 106 * @draft ICU 67
jpayne@69 107 */
jpayne@69 108 StringPiece(const std::u8string& str)
jpayne@69 109 : ptr_(reinterpret_cast<const char*>(str.data())),
jpayne@69 110 length_(static_cast<int32_t>(str.size())) { }
jpayne@69 111 #endif
jpayne@69 112 #endif // U_HIDE_DRAFT_API
jpayne@69 113
jpayne@69 114 #ifndef U_HIDE_DRAFT_API
jpayne@69 115 /**
jpayne@69 116 * Constructs from some other implementation of a string piece class, from any
jpayne@69 117 * C++ record type that has these two methods:
jpayne@69 118 *
jpayne@69 119 * \code{.cpp}
jpayne@69 120 *
jpayne@69 121 * struct OtherStringPieceClass {
jpayne@69 122 * const char* data(); // or const char8_t*
jpayne@69 123 * size_t size();
jpayne@69 124 * };
jpayne@69 125 *
jpayne@69 126 * \endcode
jpayne@69 127 *
jpayne@69 128 * The other string piece class will typically be std::string_view from C++17
jpayne@69 129 * or absl::string_view from Abseil.
jpayne@69 130 *
jpayne@69 131 * Starting with C++20, data() may also return a const char8_t* pointer,
jpayne@69 132 * as from std::u8string_view.
jpayne@69 133 *
jpayne@69 134 * @param str the other string piece
jpayne@69 135 * @draft ICU 65
jpayne@69 136 */
jpayne@69 137 template <typename T,
jpayne@69 138 typename = typename std::enable_if<
jpayne@69 139 (std::is_same<decltype(T().data()), const char*>::value
jpayne@69 140 #if defined(__cpp_char8_t)
jpayne@69 141 || std::is_same<decltype(T().data()), const char8_t*>::value
jpayne@69 142 #endif
jpayne@69 143 ) &&
jpayne@69 144 std::is_same<decltype(T().size()), size_t>::value>::type>
jpayne@69 145 StringPiece(T str)
jpayne@69 146 : ptr_(reinterpret_cast<const char*>(str.data())),
jpayne@69 147 length_(static_cast<int32_t>(str.size())) {}
jpayne@69 148 #endif // U_HIDE_DRAFT_API
jpayne@69 149
jpayne@69 150 /**
jpayne@69 151 * Constructs from a const char * pointer and a specified length.
jpayne@69 152 * @param offset a const char * pointer (need not be terminated)
jpayne@69 153 * @param len the length of the string; must be non-negative
jpayne@69 154 * @stable ICU 4.2
jpayne@69 155 */
jpayne@69 156 StringPiece(const char* offset, int32_t len) : ptr_(offset), length_(len) { }
jpayne@69 157 #ifndef U_HIDE_DRAFT_API
jpayne@69 158 #if defined(__cpp_char8_t) || defined(U_IN_DOXYGEN)
jpayne@69 159 /**
jpayne@69 160 * Constructs from a const char8_t * pointer and a specified length.
jpayne@69 161 * @param str a const char8_t * pointer (need not be terminated)
jpayne@69 162 * @param len the length of the string; must be non-negative
jpayne@69 163 * @draft ICU 67
jpayne@69 164 */
jpayne@69 165 StringPiece(const char8_t* str, int32_t len) :
jpayne@69 166 StringPiece(reinterpret_cast<const char*>(str), len) {}
jpayne@69 167 #endif
jpayne@69 168 #endif // U_HIDE_DRAFT_API
jpayne@69 169
jpayne@69 170 /**
jpayne@69 171 * Substring of another StringPiece.
jpayne@69 172 * @param x the other StringPiece
jpayne@69 173 * @param pos start position in x; must be non-negative and <= x.length().
jpayne@69 174 * @stable ICU 4.2
jpayne@69 175 */
jpayne@69 176 StringPiece(const StringPiece& x, int32_t pos);
jpayne@69 177 /**
jpayne@69 178 * Substring of another StringPiece.
jpayne@69 179 * @param x the other StringPiece
jpayne@69 180 * @param pos start position in x; must be non-negative and <= x.length().
jpayne@69 181 * @param len length of the substring;
jpayne@69 182 * must be non-negative and will be pinned to at most x.length() - pos.
jpayne@69 183 * @stable ICU 4.2
jpayne@69 184 */
jpayne@69 185 StringPiece(const StringPiece& x, int32_t pos, int32_t len);
jpayne@69 186
jpayne@69 187 /**
jpayne@69 188 * Returns the string pointer. May be nullptr if it is empty.
jpayne@69 189 *
jpayne@69 190 * data() may return a pointer to a buffer with embedded NULs, and the
jpayne@69 191 * returned buffer may or may not be null terminated. Therefore it is
jpayne@69 192 * typically a mistake to pass data() to a routine that expects a NUL
jpayne@69 193 * terminated string.
jpayne@69 194 * @return the string pointer
jpayne@69 195 * @stable ICU 4.2
jpayne@69 196 */
jpayne@69 197 const char* data() const { return ptr_; }
jpayne@69 198 /**
jpayne@69 199 * Returns the string length. Same as length().
jpayne@69 200 * @return the string length
jpayne@69 201 * @stable ICU 4.2
jpayne@69 202 */
jpayne@69 203 int32_t size() const { return length_; }
jpayne@69 204 /**
jpayne@69 205 * Returns the string length. Same as size().
jpayne@69 206 * @return the string length
jpayne@69 207 * @stable ICU 4.2
jpayne@69 208 */
jpayne@69 209 int32_t length() const { return length_; }
jpayne@69 210 /**
jpayne@69 211 * Returns whether the string is empty.
jpayne@69 212 * @return TRUE if the string is empty
jpayne@69 213 * @stable ICU 4.2
jpayne@69 214 */
jpayne@69 215 UBool empty() const { return length_ == 0; }
jpayne@69 216
jpayne@69 217 /**
jpayne@69 218 * Sets to an empty string.
jpayne@69 219 * @stable ICU 4.2
jpayne@69 220 */
jpayne@69 221 void clear() { ptr_ = nullptr; length_ = 0; }
jpayne@69 222
jpayne@69 223 /**
jpayne@69 224 * Reset the stringpiece to refer to new data.
jpayne@69 225 * @param xdata pointer the new string data. Need not be nul terminated.
jpayne@69 226 * @param len the length of the new data
jpayne@69 227 * @stable ICU 4.8
jpayne@69 228 */
jpayne@69 229 void set(const char* xdata, int32_t len) { ptr_ = xdata; length_ = len; }
jpayne@69 230
jpayne@69 231 /**
jpayne@69 232 * Reset the stringpiece to refer to new data.
jpayne@69 233 * @param str a pointer to a NUL-terminated string.
jpayne@69 234 * @stable ICU 4.8
jpayne@69 235 */
jpayne@69 236 void set(const char* str);
jpayne@69 237
jpayne@69 238 #ifndef U_HIDE_DRAFT_API
jpayne@69 239 #if defined(__cpp_char8_t) || defined(U_IN_DOXYGEN)
jpayne@69 240 /**
jpayne@69 241 * Resets the stringpiece to refer to new data.
jpayne@69 242 * @param xdata pointer the new string data. Need not be NUL-terminated.
jpayne@69 243 * @param len the length of the new data
jpayne@69 244 * @draft ICU 67
jpayne@69 245 */
jpayne@69 246 inline void set(const char8_t* xdata, int32_t len) {
jpayne@69 247 set(reinterpret_cast<const char*>(xdata), len);
jpayne@69 248 }
jpayne@69 249
jpayne@69 250 /**
jpayne@69 251 * Resets the stringpiece to refer to new data.
jpayne@69 252 * @param str a pointer to a NUL-terminated string.
jpayne@69 253 * @draft ICU 67
jpayne@69 254 */
jpayne@69 255 inline void set(const char8_t* str) {
jpayne@69 256 set(reinterpret_cast<const char*>(str));
jpayne@69 257 }
jpayne@69 258 #endif
jpayne@69 259 #endif // U_HIDE_DRAFT_API
jpayne@69 260
jpayne@69 261 /**
jpayne@69 262 * Removes the first n string units.
jpayne@69 263 * @param n prefix length, must be non-negative and <=length()
jpayne@69 264 * @stable ICU 4.2
jpayne@69 265 */
jpayne@69 266 void remove_prefix(int32_t n) {
jpayne@69 267 if (n >= 0) {
jpayne@69 268 if (n > length_) {
jpayne@69 269 n = length_;
jpayne@69 270 }
jpayne@69 271 ptr_ += n;
jpayne@69 272 length_ -= n;
jpayne@69 273 }
jpayne@69 274 }
jpayne@69 275
jpayne@69 276 /**
jpayne@69 277 * Removes the last n string units.
jpayne@69 278 * @param n suffix length, must be non-negative and <=length()
jpayne@69 279 * @stable ICU 4.2
jpayne@69 280 */
jpayne@69 281 void remove_suffix(int32_t n) {
jpayne@69 282 if (n >= 0) {
jpayne@69 283 if (n <= length_) {
jpayne@69 284 length_ -= n;
jpayne@69 285 } else {
jpayne@69 286 length_ = 0;
jpayne@69 287 }
jpayne@69 288 }
jpayne@69 289 }
jpayne@69 290
jpayne@69 291 #ifndef U_HIDE_DRAFT_API
jpayne@69 292 /**
jpayne@69 293 * Searches the StringPiece for the given search string (needle);
jpayne@69 294 * @param needle The string for which to search.
jpayne@69 295 * @param offset Where to start searching within this string (haystack).
jpayne@69 296 * @return The offset of needle in haystack, or -1 if not found.
jpayne@69 297 * @draft ICU 67
jpayne@69 298 */
jpayne@69 299 int32_t find(StringPiece needle, int32_t offset);
jpayne@69 300
jpayne@69 301 /**
jpayne@69 302 * Compares this StringPiece with the other StringPiece, with semantics
jpayne@69 303 * similar to std::string::compare().
jpayne@69 304 * @param other The string to compare to.
jpayne@69 305 * @return below zero if this < other; above zero if this > other; 0 if this == other.
jpayne@69 306 * @draft ICU 67
jpayne@69 307 */
jpayne@69 308 int32_t compare(StringPiece other);
jpayne@69 309 #endif // U_HIDE_DRAFT_API
jpayne@69 310
jpayne@69 311 /**
jpayne@69 312 * Maximum integer, used as a default value for substring methods.
jpayne@69 313 * @stable ICU 4.2
jpayne@69 314 */
jpayne@69 315 static const int32_t npos; // = 0x7fffffff;
jpayne@69 316
jpayne@69 317 /**
jpayne@69 318 * Returns a substring of this StringPiece.
jpayne@69 319 * @param pos start position; must be non-negative and <= length().
jpayne@69 320 * @param len length of the substring;
jpayne@69 321 * must be non-negative and will be pinned to at most length() - pos.
jpayne@69 322 * @return the substring StringPiece
jpayne@69 323 * @stable ICU 4.2
jpayne@69 324 */
jpayne@69 325 StringPiece substr(int32_t pos, int32_t len = npos) const {
jpayne@69 326 return StringPiece(*this, pos, len);
jpayne@69 327 }
jpayne@69 328 };
jpayne@69 329
jpayne@69 330 /**
jpayne@69 331 * Global operator == for StringPiece
jpayne@69 332 * @param x The first StringPiece to compare.
jpayne@69 333 * @param y The second StringPiece to compare.
jpayne@69 334 * @return TRUE if the string data is equal
jpayne@69 335 * @stable ICU 4.8
jpayne@69 336 */
jpayne@69 337 U_EXPORT UBool U_EXPORT2
jpayne@69 338 operator==(const StringPiece& x, const StringPiece& y);
jpayne@69 339
jpayne@69 340 /**
jpayne@69 341 * Global operator != for StringPiece
jpayne@69 342 * @param x The first StringPiece to compare.
jpayne@69 343 * @param y The second StringPiece to compare.
jpayne@69 344 * @return TRUE if the string data is not equal
jpayne@69 345 * @stable ICU 4.8
jpayne@69 346 */
jpayne@69 347 inline UBool operator!=(const StringPiece& x, const StringPiece& y) {
jpayne@69 348 return !(x == y);
jpayne@69 349 }
jpayne@69 350
jpayne@69 351 U_NAMESPACE_END
jpayne@69 352
jpayne@69 353 #endif /* U_SHOW_CPLUSPLUS_API */
jpayne@69 354
jpayne@69 355 #endif // __STRINGPIECE_H__