jpayne@69: // © 2016 and later: Unicode, Inc. and others.
jpayne@69: // License & terms of use: http://www.unicode.org/copyright.html
jpayne@69: /*
jpayne@69: *******************************************************************************
jpayne@69: *
jpayne@69: *   Copyright (C) 1999-2011, International Business Machines
jpayne@69: *   Corporation and others.  All Rights Reserved.
jpayne@69: *
jpayne@69: *******************************************************************************
jpayne@69: *   file name:  utf.h
jpayne@69: *   encoding:   UTF-8
jpayne@69: *   tab size:   8 (not used)
jpayne@69: *   indentation:4
jpayne@69: *
jpayne@69: *   created on: 1999sep09
jpayne@69: *   created by: Markus W. Scherer
jpayne@69: */
jpayne@69: 
jpayne@69: /**
jpayne@69:  * \file
jpayne@69:  * \brief C API: Code point macros
jpayne@69:  *
jpayne@69:  * This file defines macros for checking whether a code point is
jpayne@69:  * a surrogate or a non-character etc.
jpayne@69:  *
jpayne@69:  * If U_NO_DEFAULT_INCLUDE_UTF_HEADERS is 0 then utf.h is included by utypes.h
jpayne@69:  * and itself includes utf8.h and utf16.h after some
jpayne@69:  * common definitions.
jpayne@69:  * If U_NO_DEFAULT_INCLUDE_UTF_HEADERS is 1 then each of these headers must be
jpayne@69:  * included explicitly if their definitions are used.
jpayne@69:  *
jpayne@69:  * utf8.h and utf16.h define macros for efficiently getting code points
jpayne@69:  * in and out of UTF-8/16 strings.
jpayne@69:  * utf16.h macros have "U16_" prefixes.
jpayne@69:  * utf8.h defines similar macros with "U8_" prefixes for UTF-8 string handling.
jpayne@69:  *
jpayne@69:  * ICU mostly processes 16-bit Unicode strings.
jpayne@69:  * Most of the time, such strings are well-formed UTF-16.
jpayne@69:  * Single, unpaired surrogates must be handled as well, and are treated in ICU
jpayne@69:  * like regular code points where possible.
jpayne@69:  * (Pairs of surrogate code points are indistinguishable from supplementary
jpayne@69:  * code points encoded as pairs of supplementary code units.)
jpayne@69:  *
jpayne@69:  * In fact, almost all Unicode code points in normal text (>99%)
jpayne@69:  * are on the BMP (<=U+ffff) and even <=U+d7ff.
jpayne@69:  * ICU functions handle supplementary code points (U+10000..U+10ffff)
jpayne@69:  * but are optimized for the much more frequently occurring BMP code points.
jpayne@69:  *
jpayne@69:  * umachine.h defines UChar to be an unsigned 16-bit integer.
jpayne@69:  * Since ICU 59, ICU uses char16_t in C++, UChar only in C,
jpayne@69:  * and defines UChar=char16_t by default. See the UChar API docs for details.
jpayne@69:  *
jpayne@69:  * UChar32 is defined to be a signed 32-bit integer (int32_t), large enough for a 21-bit
jpayne@69:  * Unicode code point (Unicode scalar value, 0..0x10ffff) and U_SENTINEL (-1).
jpayne@69:  * Before ICU 2.4, the definition of UChar32 was similarly platform-dependent as
jpayne@69:  * the definition of UChar. For details see the documentation for UChar32 itself.
jpayne@69:  *
jpayne@69:  * utf.h defines a small number of C macros for single Unicode code points.
jpayne@69:  * These are simple checks for surrogates and non-characters.
jpayne@69:  * For actual Unicode character properties see uchar.h.
jpayne@69:  *
jpayne@69:  * By default, string operations must be done with error checking in case
jpayne@69:  * a string is not well-formed UTF-16 or UTF-8.
jpayne@69:  *
jpayne@69:  * The U16_ macros detect if a surrogate code unit is unpaired
jpayne@69:  * (lead unit without trail unit or vice versa) and just return the unit itself
jpayne@69:  * as the code point.
jpayne@69:  *
jpayne@69:  * The U8_ macros detect illegal byte sequences and return a negative value.
jpayne@69:  * Starting with ICU 60, the observable length of a single illegal byte sequence
jpayne@69:  * skipped by one of these macros follows the Unicode 6+ recommendation
jpayne@69:  * which is consistent with the W3C Encoding Standard.
jpayne@69:  *
jpayne@69:  * There are ..._OR_FFFD versions of both U16_ and U8_ macros
jpayne@69:  * that return U+FFFD for illegal code unit sequences.
jpayne@69:  *
jpayne@69:  * The regular "safe" macros require that the initial, passed-in string index
jpayne@69:  * is within bounds. They only check the index when they read more than one
jpayne@69:  * code unit. This is usually done with code similar to the following loop:
jpayne@69:  * <pre>while(i<length) {
jpayne@69:  *   U16_NEXT(s, i, length, c);
jpayne@69:  *   // use c
jpayne@69:  * }</pre>
jpayne@69:  *
jpayne@69:  * When it is safe to assume that text is well-formed UTF-16
jpayne@69:  * (does not contain single, unpaired surrogates), then one can use
jpayne@69:  * U16_..._UNSAFE macros.
jpayne@69:  * These do not check for proper code unit sequences or truncated text and may
jpayne@69:  * yield wrong results or even cause a crash if they are used with "malformed"
jpayne@69:  * text.
jpayne@69:  * In practice, U16_..._UNSAFE macros will produce slightly less code but
jpayne@69:  * should not be faster because the processing is only different when a
jpayne@69:  * surrogate code unit is detected, which will be rare.
jpayne@69:  *
jpayne@69:  * Similarly for UTF-8, there are "safe" macros without a suffix,
jpayne@69:  * and U8_..._UNSAFE versions.
jpayne@69:  * The performance differences are much larger here because UTF-8 provides so
jpayne@69:  * many opportunities for malformed sequences.
jpayne@69:  * The unsafe UTF-8 macros are entirely implemented inside the macro definitions
jpayne@69:  * and are fast, while the safe UTF-8 macros call functions for some complicated cases.
jpayne@69:  *
jpayne@69:  * Unlike with UTF-16, malformed sequences cannot be expressed with distinct
jpayne@69:  * code point values (0..U+10ffff). They are indicated with negative values instead.
jpayne@69:  *
jpayne@69:  * For more information see the ICU User Guide Strings chapter
jpayne@69:  * (http://userguide.icu-project.org/strings).
jpayne@69:  *
jpayne@69:  * <em>Usage:</em>
jpayne@69:  * ICU coding guidelines for if() statements should be followed when using these macros.
jpayne@69:  * Compound statements (curly braces {}) must be used  for if-else-while... 
jpayne@69:  * bodies and all macro statements should be terminated with semicolon.
jpayne@69:  *
jpayne@69:  * @stable ICU 2.4
jpayne@69:  */
jpayne@69: 
jpayne@69: #ifndef __UTF_H__
jpayne@69: #define __UTF_H__
jpayne@69: 
jpayne@69: #include "unicode/umachine.h"
jpayne@69: /* include the utfXX.h after the following definitions */
jpayne@69: 
jpayne@69: /* single-code point definitions -------------------------------------------- */
jpayne@69: 
jpayne@69: /**
jpayne@69:  * Is this code point a Unicode noncharacter?
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 2.4
jpayne@69:  */
jpayne@69: #define U_IS_UNICODE_NONCHAR(c) \
jpayne@69:     ((c)>=0xfdd0 && \
jpayne@69:      ((c)<=0xfdef || ((c)&0xfffe)==0xfffe) && (c)<=0x10ffff)
jpayne@69: 
jpayne@69: /**
jpayne@69:  * Is c a Unicode code point value (0..U+10ffff)
jpayne@69:  * that can be assigned a character?
jpayne@69:  *
jpayne@69:  * Code points that are not characters include:
jpayne@69:  * - single surrogate code points (U+d800..U+dfff, 2048 code points)
jpayne@69:  * - the last two code points on each plane (U+__fffe and U+__ffff, 34 code points)
jpayne@69:  * - U+fdd0..U+fdef (new with Unicode 3.1, 32 code points)
jpayne@69:  * - the highest Unicode code point value is U+10ffff
jpayne@69:  *
jpayne@69:  * This means that all code points below U+d800 are character code points,
jpayne@69:  * and that boundary is tested first for performance.
jpayne@69:  *
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 2.4
jpayne@69:  */
jpayne@69: #define U_IS_UNICODE_CHAR(c) \
jpayne@69:     ((uint32_t)(c)<0xd800 || \
jpayne@69:         (0xdfff<(c) && (c)<=0x10ffff && !U_IS_UNICODE_NONCHAR(c)))
jpayne@69: 
jpayne@69: /**
jpayne@69:  * Is this code point a BMP code point (U+0000..U+ffff)?
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 2.8
jpayne@69:  */
jpayne@69: #define U_IS_BMP(c) ((uint32_t)(c)<=0xffff)
jpayne@69: 
jpayne@69: /**
jpayne@69:  * Is this code point a supplementary code point (U+10000..U+10ffff)?
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 2.8
jpayne@69:  */
jpayne@69: #define U_IS_SUPPLEMENTARY(c) ((uint32_t)((c)-0x10000)<=0xfffff)
jpayne@69:  
jpayne@69: /**
jpayne@69:  * Is this code point a lead surrogate (U+d800..U+dbff)?
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 2.4
jpayne@69:  */
jpayne@69: #define U_IS_LEAD(c) (((c)&0xfffffc00)==0xd800)
jpayne@69: 
jpayne@69: /**
jpayne@69:  * Is this code point a trail surrogate (U+dc00..U+dfff)?
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 2.4
jpayne@69:  */
jpayne@69: #define U_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00)
jpayne@69: 
jpayne@69: /**
jpayne@69:  * Is this code point a surrogate (U+d800..U+dfff)?
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 2.4
jpayne@69:  */
jpayne@69: #define U_IS_SURROGATE(c) (((c)&0xfffff800)==0xd800)
jpayne@69: 
jpayne@69: /**
jpayne@69:  * Assuming c is a surrogate code point (U_IS_SURROGATE(c)),
jpayne@69:  * is it a lead surrogate?
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 2.4
jpayne@69:  */
jpayne@69: #define U_IS_SURROGATE_LEAD(c) (((c)&0x400)==0)
jpayne@69: 
jpayne@69: /**
jpayne@69:  * Assuming c is a surrogate code point (U_IS_SURROGATE(c)),
jpayne@69:  * is it a trail surrogate?
jpayne@69:  * @param c 32-bit code point
jpayne@69:  * @return TRUE or FALSE
jpayne@69:  * @stable ICU 4.2
jpayne@69:  */
jpayne@69: #define U_IS_SURROGATE_TRAIL(c) (((c)&0x400)!=0)
jpayne@69: 
jpayne@69: /* include the utfXX.h ------------------------------------------------------ */
jpayne@69: 
jpayne@69: #if !U_NO_DEFAULT_INCLUDE_UTF_HEADERS
jpayne@69: 
jpayne@69: #include "unicode/utf8.h"
jpayne@69: #include "unicode/utf16.h"
jpayne@69: 
jpayne@69: /* utf_old.h contains deprecated, pre-ICU 2.4 definitions */
jpayne@69: #include "unicode/utf_old.h"
jpayne@69: 
jpayne@69: #endif  /* !U_NO_DEFAULT_INCLUDE_UTF_HEADERS */
jpayne@69: 
jpayne@69: #endif  /* __UTF_H__ */