diff options
Diffstat (limited to 'deps/icu-small/source/common/unicode/utf8.h')
| -rw-r--r-- | deps/icu-small/source/common/unicode/utf8.h | 824 |
1 files changed, 824 insertions, 0 deletions
diff --git a/deps/icu-small/source/common/unicode/utf8.h b/deps/icu-small/source/common/unicode/utf8.h new file mode 100644 index 0000000000..94a0134240 --- /dev/null +++ b/deps/icu-small/source/common/unicode/utf8.h @@ -0,0 +1,824 @@ +/* +******************************************************************************* +* +* Copyright (C) 1999-2015, International Business Machines +* Corporation and others. All Rights Reserved. +* +******************************************************************************* +* file name: utf8.h +* encoding: US-ASCII +* tab size: 8 (not used) +* indentation:4 +* +* created on: 1999sep13 +* created by: Markus W. Scherer +*/ + +/** + * \file + * \brief C API: 8-bit Unicode handling macros + * + * This file defines macros to deal with 8-bit Unicode (UTF-8) code units (bytes) and strings. + * + * For more information see utf.h and the ICU User Guide Strings chapter + * (http://userguide.icu-project.org/strings). + * + * <em>Usage:</em> + * ICU coding guidelines for if() statements should be followed when using these macros. + * Compound statements (curly braces {}) must be used for if-else-while... + * bodies and all macro statements should be terminated with semicolon. + */ + +#ifndef __UTF8_H__ +#define __UTF8_H__ + +#include "unicode/umachine.h" +#ifndef __UTF_H__ +# include "unicode/utf.h" +#endif + +/* internal definitions ----------------------------------------------------- */ + +/** + * \var utf8_countTrailBytes + * Internal array with numbers of trail bytes for any given byte used in + * lead byte position. + * + * This is internal since it is not meant to be called directly by external clients; + * however it is called by public macros in this file and thus must remain stable, + * and should not be hidden when other internal functions are hidden (otherwise + * public macros would fail to compile). + * @internal + */ +#ifdef U_UTF8_IMPL +U_EXPORT const uint8_t +#elif defined(U_STATIC_IMPLEMENTATION) || defined(U_COMMON_IMPLEMENTATION) +U_CFUNC const uint8_t +#else +U_CFUNC U_IMPORT const uint8_t /* U_IMPORT2? */ /*U_IMPORT*/ +#endif +utf8_countTrailBytes[256]; + +/** + * Counts the trail bytes for a UTF-8 lead byte. + * Returns 0 for 0..0xbf as well as for 0xfe and 0xff. + * + * This is internal since it is not meant to be called directly by external clients; + * however it is called by public macros in this file and thus must remain stable. + * + * Note: Beginning with ICU 50, the implementation uses a multi-condition expression + * which was shown in 2012 (on x86-64) to compile to fast, branch-free code. + * leadByte is evaluated multiple times. + * + * The pre-ICU 50 implementation used the exported array utf8_countTrailBytes: + * #define U8_COUNT_TRAIL_BYTES(leadByte) (utf8_countTrailBytes[leadByte]) + * leadByte was evaluated exactly once. + * + * @param leadByte The first byte of a UTF-8 sequence. Must be 0..0xff. + * @internal + */ +#define U8_COUNT_TRAIL_BYTES(leadByte) \ + ((uint8_t)(leadByte)<0xf0 ? \ + ((uint8_t)(leadByte)>=0xc0)+((uint8_t)(leadByte)>=0xe0) : \ + (uint8_t)(leadByte)<0xfe ? 3+((uint8_t)(leadByte)>=0xf8)+((uint8_t)(leadByte)>=0xfc) : 0) + +/** + * Counts the trail bytes for a UTF-8 lead byte of a valid UTF-8 sequence. + * The maximum supported lead byte is 0xf4 corresponding to U+10FFFF. + * leadByte might be evaluated multiple times. + * + * This is internal since it is not meant to be called directly by external clients; + * however it is called by public macros in this file and thus must remain stable. + * + * @param leadByte The first byte of a UTF-8 sequence. Must be 0..0xff. + * @internal + */ +#define U8_COUNT_TRAIL_BYTES_UNSAFE(leadByte) \ + (((leadByte)>=0xc0)+((leadByte)>=0xe0)+((leadByte)>=0xf0)) + +/** + * Mask a UTF-8 lead byte, leave only the lower bits that form part of the code point value. + * + * This is internal since it is not meant to be called directly by external clients; + * however it is called by public macros in this file and thus must remain stable. + * @internal + */ +#define U8_MASK_LEAD_BYTE(leadByte, countTrailBytes) ((leadByte)&=(1<<(6-(countTrailBytes)))-1) + +/** + * Function for handling "next code point" with error-checking. + * + * This is internal since it is not meant to be called directly by external clients; + * however it is U_STABLE (not U_INTERNAL) since it is called by public macros in this + * file and thus must remain stable, and should not be hidden when other internal + * functions are hidden (otherwise public macros would fail to compile). + * @internal + */ +U_STABLE UChar32 U_EXPORT2 +utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict); + +/** + * Function for handling "append code point" with error-checking. + * + * This is internal since it is not meant to be called directly by external clients; + * however it is U_STABLE (not U_INTERNAL) since it is called by public macros in this + * file and thus must remain stable, and should not be hidden when other internal + * functions are hidden (otherwise public macros would fail to compile). + * @internal + */ +U_STABLE int32_t U_EXPORT2 +utf8_appendCharSafeBody(uint8_t *s, int32_t i, int32_t length, UChar32 c, UBool *pIsError); + +/** + * Function for handling "previous code point" with error-checking. + * + * This is internal since it is not meant to be called directly by external clients; + * however it is U_STABLE (not U_INTERNAL) since it is called by public macros in this + * file and thus must remain stable, and should not be hidden when other internal + * functions are hidden (otherwise public macros would fail to compile). + * @internal + */ +U_STABLE UChar32 U_EXPORT2 +utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, UBool strict); + +/** + * Function for handling "skip backward one code point" with error-checking. + * + * This is internal since it is not meant to be called directly by external clients; + * however it is U_STABLE (not U_INTERNAL) since it is called by public macros in this + * file and thus must remain stable, and should not be hidden when other internal + * functions are hidden (otherwise public macros would fail to compile). + * @internal + */ +U_STABLE int32_t U_EXPORT2 +utf8_back1SafeBody(const uint8_t *s, int32_t start, int32_t i); + +/* single-code point definitions -------------------------------------------- */ + +/** + * Does this code unit (byte) encode a code point by itself (US-ASCII 0..0x7f)? + * @param c 8-bit code unit (byte) + * @return TRUE or FALSE + * @stable ICU 2.4 + */ +#define U8_IS_SINGLE(c) (((c)&0x80)==0) + +/** + * Is this code unit (byte) a UTF-8 lead byte? + * @param c 8-bit code unit (byte) + * @return TRUE or FALSE + * @stable ICU 2.4 + */ +#define U8_IS_LEAD(c) ((uint8_t)((c)-0xc0)<0x3e) + +/** + * Is this code unit (byte) a UTF-8 trail byte? + * @param c 8-bit code unit (byte) + * @return TRUE or FALSE + * @stable ICU 2.4 + */ +#define U8_IS_TRAIL(c) (((c)&0xc0)==0x80) + +/** + * How many code units (bytes) are used for the UTF-8 encoding + * of this Unicode code point? + * @param c 32-bit code point + * @return 1..4, or 0 if c is a surrogate or not a Unicode code point + * @stable ICU 2.4 + */ +#define U8_LENGTH(c) \ + ((uint32_t)(c)<=0x7f ? 1 : \ + ((uint32_t)(c)<=0x7ff ? 2 : \ + ((uint32_t)(c)<=0xd7ff ? 3 : \ + ((uint32_t)(c)<=0xdfff || (uint32_t)(c)>0x10ffff ? 0 : \ + ((uint32_t)(c)<=0xffff ? 3 : 4)\ + ) \ + ) \ + ) \ + ) + +/** + * The maximum number of UTF-8 code units (bytes) per Unicode code point (U+0000..U+10ffff). + * @return 4 + * @stable ICU 2.4 + */ +#define U8_MAX_LENGTH 4 + +/** + * Get a code point from a string at a random-access offset, + * without changing the offset. + * The offset may point to either the lead byte or one of the trail bytes + * for a code point, in which case the macro will read all of the bytes + * for the code point. + * The result is undefined if the offset points to an illegal UTF-8 + * byte sequence. + * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT. + * + * @param s const uint8_t * string + * @param i string offset + * @param c output UChar32 variable + * @see U8_GET + * @stable ICU 2.4 + */ +#define U8_GET_UNSAFE(s, i, c) { \ + int32_t _u8_get_unsafe_index=(int32_t)(i); \ + U8_SET_CP_START_UNSAFE(s, _u8_get_unsafe_index); \ + U8_NEXT_UNSAFE(s, _u8_get_unsafe_index, c); \ +} + +/** + * Get a code point from a string at a random-access offset, + * without changing the offset. + * The offset may point to either the lead byte or one of the trail bytes + * for a code point, in which case the macro will read all of the bytes + * for the code point. + * + * The length can be negative for a NUL-terminated string. + * + * If the offset points to an illegal UTF-8 byte sequence, then + * c is set to a negative value. + * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT. + * + * @param s const uint8_t * string + * @param start int32_t starting string offset + * @param i int32_t string offset, must be start<=i<length + * @param length int32_t string length + * @param c output UChar32 variable, set to <0 in case of an error + * @see U8_GET_UNSAFE + * @stable ICU 2.4 + */ +#define U8_GET(s, start, i, length, c) { \ + int32_t _u8_get_index=(i); \ + U8_SET_CP_START(s, start, _u8_get_index); \ + U8_NEXT(s, _u8_get_index, length, c); \ +} + +/** + * Get a code point from a string at a random-access offset, + * without changing the offset. + * The offset may point to either the lead byte or one of the trail bytes + * for a code point, in which case the macro will read all of the bytes + * for the code point. + * + * The length can be negative for a NUL-terminated string. + * + * If the offset points to an illegal UTF-8 byte sequence, then + * c is set to U+FFFD. + * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT_OR_FFFD. + * + * This macro does not distinguish between a real U+FFFD in the text + * and U+FFFD returned for an ill-formed sequence. + * Use U8_GET() if that distinction is important. + * + * @param s const uint8_t * string + * @param start int32_t starting string offset + * @param i int32_t string offset, must be start<=i<length + * @param length int32_t string length + * @param c output UChar32 variable, set to U+FFFD in case of an error + * @see U8_GET + * @stable ICU 51 + */ +#define U8_GET_OR_FFFD(s, start, i, length, c) { \ + int32_t _u8_get_index=(i); \ + U8_SET_CP_START(s, start, _u8_get_index); \ + U8_NEXT_OR_FFFD(s, _u8_get_index, length, c); \ +} + +/* definitions with forward iteration --------------------------------------- */ + +/** + * Get a code point from a string at a code point boundary offset, + * and advance the offset to the next code point boundary. + * (Post-incrementing forward iteration.) + * "Unsafe" macro, assumes well-formed UTF-8. + * + * The offset may point to the lead byte of a multi-byte sequence, + * in which case the macro will read the whole sequence. + * The result is undefined if the offset points to a trail byte + * or an illegal UTF-8 sequence. + * + * @param s const uint8_t * string + * @param i string offset + * @param c output UChar32 variable + * @see U8_NEXT + * @stable ICU 2.4 + */ +#define U8_NEXT_UNSAFE(s, i, c) { \ + (c)=(uint8_t)(s)[(i)++]; \ + if((c)>=0x80) { \ + if((c)<0xe0) { \ + (c)=(((c)&0x1f)<<6)|((s)[(i)++]&0x3f); \ + } else if((c)<0xf0) { \ + /* no need for (c&0xf) because the upper bits are truncated after <<12 in the cast to (UChar) */ \ + (c)=(UChar)(((c)<<12)|(((s)[i]&0x3f)<<6)|((s)[(i)+1]&0x3f)); \ + (i)+=2; \ + } else { \ + (c)=(((c)&7)<<18)|(((s)[i]&0x3f)<<12)|(((s)[(i)+1]&0x3f)<<6)|((s)[(i)+2]&0x3f); \ + (i)+=3; \ + } \ + } \ +} + +/** + * Get a code point from a string at a code point boundary offset, + * and advance the offset to the next code point boundary. + * (Post-incrementing forward iteration.) + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * The length can be negative for a NUL-terminated string. + * + * The offset may point to the lead byte of a multi-byte sequence, + * in which case the macro will read the whole sequence. + * If the offset points to a trail byte or an illegal UTF-8 sequence, then + * c is set to a negative value. + * + * @param s const uint8_t * string + * @param i int32_t string offset, must be i<length + * @param length int32_t string length + * @param c output UChar32 variable, set to <0 in case of an error + * @see U8_NEXT_UNSAFE + * @stable ICU 2.4 + */ +#define U8_NEXT(s, i, length, c) { \ + (c)=(uint8_t)(s)[(i)++]; \ + if((c)>=0x80) { \ + uint8_t __t1, __t2; \ + if( /* handle U+1000..U+CFFF inline */ \ + (0xe0<(c) && (c)<=0xec) && \ + (((i)+1)<(length) || (length)<0) && \ + (__t1=(uint8_t)((s)[i]-0x80))<=0x3f && \ + (__t2=(uint8_t)((s)[(i)+1]-0x80))<= 0x3f \ + ) { \ + /* no need for (c&0xf) because the upper bits are truncated after <<12 in the cast to (UChar) */ \ + (c)=(UChar)(((c)<<12)|(__t1<<6)|__t2); \ + (i)+=2; \ + } else if( /* handle U+0080..U+07FF inline */ \ + ((c)<0xe0 && (c)>=0xc2) && \ + ((i)!=(length)) && \ + (__t1=(uint8_t)((s)[i]-0x80))<=0x3f \ + ) { \ + (c)=(((c)&0x1f)<<6)|__t1; \ + ++(i); \ + } else { \ + /* function call for "complicated" and error cases */ \ + (c)=utf8_nextCharSafeBody((const uint8_t *)s, &(i), (length), c, -1); \ + } \ + } \ +} + +/** + * Get a code point from a string at a code point boundary offset, + * and advance the offset to the next code point boundary. + * (Post-incrementing forward iteration.) + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * The length can be negative for a NUL-terminated string. + * + * The offset may point to the lead byte of a multi-byte sequence, + * in which case the macro will read the whole sequence. + * If the offset points to a trail byte or an illegal UTF-8 sequence, then + * c is set to U+FFFD. + * + * This macro does not distinguish between a real U+FFFD in the text + * and U+FFFD returned for an ill-formed sequence. + * Use U8_NEXT() if that distinction is important. + * + * @param s const uint8_t * string + * @param i int32_t string offset, must be i<length + * @param length int32_t string length + * @param c output UChar32 variable, set to U+FFFD in case of an error + * @see U8_NEXT + * @stable ICU 51 + */ +#define U8_NEXT_OR_FFFD(s, i, length, c) { \ + (c)=(uint8_t)(s)[(i)++]; \ + if((c)>=0x80) { \ + uint8_t __t1, __t2; \ + if( /* handle U+1000..U+CFFF inline */ \ + (0xe0<(c) && (c)<=0xec) && \ + (((i)+1)<(length) || (length)<0) && \ + (__t1=(uint8_t)((s)[i]-0x80))<=0x3f && \ + (__t2=(uint8_t)((s)[(i)+1]-0x80))<= 0x3f \ + ) { \ + /* no need for (c&0xf) because the upper bits are truncated after <<12 in the cast to (UChar) */ \ + (c)=(UChar)(((c)<<12)|(__t1<<6)|__t2); \ + (i)+=2; \ + } else if( /* handle U+0080..U+07FF inline */ \ + ((c)<0xe0 && (c)>=0xc2) && \ + ((i)!=(length)) && \ + (__t1=(uint8_t)((s)[i]-0x80))<=0x3f \ + ) { \ + (c)=(((c)&0x1f)<<6)|__t1; \ + ++(i); \ + } else { \ + /* function call for "complicated" and error cases */ \ + (c)=utf8_nextCharSafeBody((const uint8_t *)s, &(i), (length), c, -3); \ + } \ + } \ +} + +/** + * Append a code point to a string, overwriting 1 to 4 bytes. + * The offset points to the current end of the string contents + * and is advanced (post-increment). + * "Unsafe" macro, assumes a valid code point and sufficient space in the string. + * Otherwise, the result is undefined. + * + * @param s const uint8_t * string buffer + * @param i string offset + * @param c code point to append + * @see U8_APPEND + * @stable ICU 2.4 + */ +#define U8_APPEND_UNSAFE(s, i, c) { \ + if((uint32_t)(c)<=0x7f) { \ + (s)[(i)++]=(uint8_t)(c); \ + } else { \ + if((uint32_t)(c)<=0x7ff) { \ + (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); \ + } else { \ + if((uint32_t)(c)<=0xffff) { \ + (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); \ + } else { \ + (s)[(i)++]=(uint8_t)(((c)>>18)|0xf0); \ + (s)[(i)++]=(uint8_t)((((c)>>12)&0x3f)|0x80); \ + } \ + (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); \ + } \ + (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); \ + } \ +} + +/** + * Append a code point to a string, overwriting 1 to 4 bytes. + * The offset points to the current end of the string contents + * and is advanced (post-increment). + * "Safe" macro, checks for a valid code point. + * If a non-ASCII code point is written, checks for sufficient space in the string. + * If the code point is not valid or trail bytes do not fit, + * then isError is set to TRUE. + * + * @param s const uint8_t * string buffer + * @param i int32_t string offset, must be i<capacity + * @param capacity int32_t size of the string buffer + * @param c UChar32 code point to append + * @param isError output UBool set to TRUE if an error occurs, otherwise not modified + * @see U8_APPEND_UNSAFE + * @stable ICU 2.4 + */ +#define U8_APPEND(s, i, capacity, c, isError) { \ + if((uint32_t)(c)<=0x7f) { \ + (s)[(i)++]=(uint8_t)(c); \ + } else if((uint32_t)(c)<=0x7ff && (i)+1<(capacity)) { \ + (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); \ + (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); \ + } else if((uint32_t)(c)<=0xd7ff && (i)+2<(capacity)) { \ + (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); \ + (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); \ + (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); \ + } else { \ + (i)=utf8_appendCharSafeBody(s, (i), (capacity), c, &(isError)); \ + } \ +} + +/** + * Advance the string offset from one code point boundary to the next. + * (Post-incrementing iteration.) + * "Unsafe" macro, assumes well-formed UTF-8. + * + * @param s const uint8_t * string + * @param i string offset + * @see U8_FWD_1 + * @stable ICU 2.4 + */ +#define U8_FWD_1_UNSAFE(s, i) { \ + (i)+=1+U8_COUNT_TRAIL_BYTES_UNSAFE((uint8_t)(s)[i]); \ +} + +/** + * Advance the string offset from one code point boundary to the next. + * (Post-incrementing iteration.) + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * The length can be negative for a NUL-terminated string. + * + * @param s const uint8_t * string + * @param i int32_t string offset, must be i<length + * @param length int32_t string length + * @see U8_FWD_1_UNSAFE + * @stable ICU 2.4 + */ +#define U8_FWD_1(s, i, length) { \ + uint8_t __b=(uint8_t)(s)[(i)++]; \ + if(U8_IS_LEAD(__b)) { \ + uint8_t __count=U8_COUNT_TRAIL_BYTES(__b); \ + if((i)+__count>(length) && (length)>=0) { \ + __count=(uint8_t)((length)-(i)); \ + } \ + while(__count>0 && U8_IS_TRAIL((s)[i])) { \ + ++(i); \ + --__count; \ + } \ + } \ +} + +/** + * Advance the string offset from one code point boundary to the n-th next one, + * i.e., move forward by n code points. + * (Post-incrementing iteration.) + * "Unsafe" macro, assumes well-formed UTF-8. + * + * @param s const uint8_t * string + * @param i string offset + * @param n number of code points to skip + * @see U8_FWD_N + * @stable ICU 2.4 + */ +#define U8_FWD_N_UNSAFE(s, i, n) { \ + int32_t __N=(n); \ + while(__N>0) { \ + U8_FWD_1_UNSAFE(s, i); \ + --__N; \ + } \ +} + +/** + * Advance the string offset from one code point boundary to the n-th next one, + * i.e., move forward by n code points. + * (Post-incrementing iteration.) + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * The length can be negative for a NUL-terminated string. + * + * @param s const uint8_t * string + * @param i int32_t string offset, must be i<length + * @param length int32_t string length + * @param n number of code points to skip + * @see U8_FWD_N_UNSAFE + * @stable ICU 2.4 + */ +#define U8_FWD_N(s, i, length, n) { \ + int32_t __N=(n); \ + while(__N>0 && ((i)<(length) || ((length)<0 && (s)[i]!=0))) { \ + U8_FWD_1(s, i, length); \ + --__N; \ + } \ +} + +/** + * Adjust a random-access offset to a code point boundary + * at the start of a code point. + * If the offset points to a UTF-8 trail byte, + * then the offset is moved backward to the corresponding lead byte. + * Otherwise, it is not modified. + * "Unsafe" macro, assumes well-formed UTF-8. + * + * @param s const uint8_t * string + * @param i string offset + * @see U8_SET_CP_START + * @stable ICU 2.4 + */ +#define U8_SET_CP_START_UNSAFE(s, i) { \ + while(U8_IS_TRAIL((s)[i])) { --(i); } \ +} + +/** + * Adjust a random-access offset to a code point boundary + * at the start of a code point. + * If the offset points to a UTF-8 trail byte, + * then the offset is moved backward to the corresponding lead byte. + * Otherwise, it is not modified. + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * @param s const uint8_t * string + * @param start int32_t starting string offset (usually 0) + * @param i int32_t string offset, must be start<=i + * @see U8_SET_CP_START_UNSAFE + * @stable ICU 2.4 + */ +#define U8_SET_CP_START(s, start, i) { \ + if(U8_IS_TRAIL((s)[(i)])) { \ + (i)=utf8_back1SafeBody(s, start, (i)); \ + } \ +} + +/* definitions with backward iteration -------------------------------------- */ + +/** + * Move the string offset from one code point boundary to the previous one + * and get the code point between them. + * (Pre-decrementing backward iteration.) + * "Unsafe" macro, assumes well-formed UTF-8. + * + * The input offset may be the same as the string length. + * If the offset is behind a multi-byte sequence, then the macro will read + * the whole sequence. + * If the offset is behind a lead byte, then that itself + * will be returned as the code point. + * The result is undefined if the offset is behind an illegal UTF-8 sequence. + * + * @param s const uint8_t * string + * @param i string offset + * @param c output UChar32 variable + * @see U8_PREV + * @stable ICU 2.4 + */ +#define U8_PREV_UNSAFE(s, i, c) { \ + (c)=(uint8_t)(s)[--(i)]; \ + if(U8_IS_TRAIL(c)) { \ + uint8_t __b, __count=1, __shift=6; \ +\ + /* c is a trail byte */ \ + (c)&=0x3f; \ + for(;;) { \ + __b=(uint8_t)(s)[--(i)]; \ + if(__b>=0xc0) { \ + U8_MASK_LEAD_BYTE(__b, __count); \ + (c)|=(UChar32)__b<<__shift; \ + break; \ + } else { \ + (c)|=(UChar32)(__b&0x3f)<<__shift; \ + ++__count; \ + __shift+=6; \ + } \ + } \ + } \ +} + +/** + * Move the string offset from one code point boundary to the previous one + * and get the code point between them. + * (Pre-decrementing backward iteration.) + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * The input offset may be the same as the string length. + * If the offset is behind a multi-byte sequence, then the macro will read + * the whole sequence. + * If the offset is behind a lead byte, then that itself + * will be returned as the code point. + * If the offset is behind an illegal UTF-8 sequence, then c is set to a negative value. + * + * @param s const uint8_t * string + * @param start int32_t starting string offset (usually 0) + * @param i int32_t string offset, must be start<i + * @param c output UChar32 variable, set to <0 in case of an error + * @see U8_PREV_UNSAFE + * @stable ICU 2.4 + */ +#define U8_PREV(s, start, i, c) { \ + (c)=(uint8_t)(s)[--(i)]; \ + if((c)>=0x80) { \ + (c)=utf8_prevCharSafeBody((const uint8_t *)s, start, &(i), c, -1); \ + } \ +} + +/** + * Move the string offset from one code point boundary to the previous one + * and get the code point between them. + * (Pre-decrementing backward iteration.) + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * The input offset may be the same as the string length. + * If the offset is behind a multi-byte sequence, then the macro will read + * the whole sequence. + * If the offset is behind a lead byte, then that itself + * will be returned as the code point. + * If the offset is behind an illegal UTF-8 sequence, then c is set to U+FFFD. + * + * This macro does not distinguish between a real U+FFFD in the text + * and U+FFFD returned for an ill-formed sequence. + * Use U8_PREV() if that distinction is important. + * + * @param s const uint8_t * string + * @param start int32_t starting string offset (usually 0) + * @param i int32_t string offset, must be start<i + * @param c output UChar32 variable, set to U+FFFD in case of an error + * @see U8_PREV + * @stable ICU 51 + */ +#define U8_PREV_OR_FFFD(s, start, i, c) { \ + (c)=(uint8_t)(s)[--(i)]; \ + if((c)>=0x80) { \ + (c)=utf8_prevCharSafeBody((const uint8_t *)s, start, &(i), c, -3); \ + } \ +} + +/** + * Move the string offset from one code point boundary to the previous one. + * (Pre-decrementing backward iteration.) + * The input offset may be the same as the string length. + * "Unsafe" macro, assumes well-formed UTF-8. + * + * @param s const uint8_t * string + * @param i string offset + * @see U8_BACK_1 + * @stable ICU 2.4 + */ +#define U8_BACK_1_UNSAFE(s, i) { \ + while(U8_IS_TRAIL((s)[--(i)])) {} \ +} + +/** + * Move the string offset from one code point boundary to the previous one. + * (Pre-decrementing backward iteration.) + * The input offset may be the same as the string length. + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * @param s const uint8_t * string + * @param start int32_t starting string offset (usually 0) + * @param i int32_t string offset, must be start<i + * @see U8_BACK_1_UNSAFE + * @stable ICU 2.4 + */ +#define U8_BACK_1(s, start, i) { \ + if(U8_IS_TRAIL((s)[--(i)])) { \ + (i)=utf8_back1SafeBody(s, start, (i)); \ + } \ +} + +/** + * Move the string offset from one code point boundary to the n-th one before it, + * i.e., move backward by n code points. + * (Pre-decrementing backward iteration.) + * The input offset may be the same as the string length. + * "Unsafe" macro, assumes well-formed UTF-8. + * + * @param s const uint8_t * string + * @param i string offset + * @param n number of code points to skip + * @see U8_BACK_N + * @stable ICU 2.4 + */ +#define U8_BACK_N_UNSAFE(s, i, n) { \ + int32_t __N=(n); \ + while(__N>0) { \ + U8_BACK_1_UNSAFE(s, i); \ + --__N; \ + } \ +} + +/** + * Move the string offset from one code point boundary to the n-th one before it, + * i.e., move backward by n code points. + * (Pre-decrementing backward iteration.) + * The input offset may be the same as the string length. + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * @param s const uint8_t * string + * @param start int32_t index of the start of the string + * @param i int32_t string offset, must be start<i + * @param n number of code points to skip + * @see U8_BACK_N_UNSAFE + * @stable ICU 2.4 + */ +#define U8_BACK_N(s, start, i, n) { \ + int32_t __N=(n); \ + while(__N>0 && (i)>(start)) { \ + U8_BACK_1(s, start, i); \ + --__N; \ + } \ +} + +/** + * Adjust a random-access offset to a code point boundary after a code point. + * If the offset is behind a partial multi-byte sequence, + * then the offset is incremented to behind the whole sequence. + * Otherwise, it is not modified. + * The input offset may be the same as the string length. + * "Unsafe" macro, assumes well-formed UTF-8. + * + * @param s const uint8_t * string + * @param i string offset + * @see U8_SET_CP_LIMIT + * @stable ICU 2.4 + */ +#define U8_SET_CP_LIMIT_UNSAFE(s, i) { \ + U8_BACK_1_UNSAFE(s, i); \ + U8_FWD_1_UNSAFE(s, i); \ +} + +/** + * Adjust a random-access offset to a code point boundary after a code point. + * If the offset is behind a partial multi-byte sequence, + * then the offset is incremented to behind the whole sequence. + * Otherwise, it is not modified. + * The input offset may be the same as the string length. + * "Safe" macro, checks for illegal sequences and for string boundaries. + * + * The length can be negative for a NUL-terminated string. + * + * @param s const uint8_t * string + * @param start int32_t starting string offset (usually 0) + * @param i int32_t string offset, must be start<=i<=length + * @param length int32_t string length + * @see U8_SET_CP_LIMIT_UNSAFE + * @stable ICU 2.4 + */ +#define U8_SET_CP_LIMIT(s, start, i, length) { \ + if((start)<(i) && ((i)<(length) || (length)<0)) { \ + U8_BACK_1(s, start, i); \ + U8_FWD_1(s, i, length); \ + } \ +} + +#endif |