318 lines
9.0 KiB
C
318 lines
9.0 KiB
C
/*
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*******************************************************************************
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*
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* Copyright (C) 1999-2000, International Business Machines
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* Corporation and others. All Rights Reserved.
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*
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*******************************************************************************
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* file name: utf8.h
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* encoding: US-ASCII
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* tab size: 8 (not used)
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* indentation:4
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*
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* created on: 1999sep13
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* created by: Markus W. Scherer
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*/
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/**
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* \file
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* \brief C API: UTF-8 macros
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*
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* This file defines macros to deal with UTF-8 code units and code points.
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* Signatures and semantics are the same as for the similarly named macros
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* in utf16.h.
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* utf8.h is included by utf.h after unicode/umachine.h
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* and some common definitions.
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*/
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/* utf.h must be included first. */
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#ifndef __UTF_H__
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# include "unicode/utf.h"
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#endif
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#ifndef __UTF8_H__
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#define __UTF8_H__
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/* internal definitions ----------------------------------------------------- */
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#ifdef U_UTF8_IMPL
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U_CAPI uint8_t U_EXPORT2
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utf8_countTrailBytes[256];
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#else
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U_CFUNC uint8_t /* U_IMPORT2? */ U_IMPORT
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utf8_countTrailBytes[256];
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#endif
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/*
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* Count the trail bytes for a lead byte -
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* this macro should be used so that the assembler code
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* that is mentioned in utf_impl.c could be used here.
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*/
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#define UTF8_COUNT_TRAIL_BYTES(leadByte) (utf8_countTrailBytes[(uint8_t)leadByte])
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/* use a macro here, too - there may be a simpler way with some machines */
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#define UTF8_MASK_LEAD_BYTE(leadByte, countTrailBytes) ((leadByte)&=(1<<(6-(countTrailBytes)))-1)
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U_CAPI UChar32 U_EXPORT2
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utf8_nextCharSafeBody(const uint8_t *s, UTextOffset *pi, UTextOffset length, UChar32 c, UBool strict);
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U_CAPI UTextOffset U_EXPORT2
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utf8_appendCharSafeBody(uint8_t *s, UTextOffset i, UTextOffset length, UChar32 c);
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U_CAPI UChar32 U_EXPORT2
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utf8_prevCharSafeBody(const uint8_t *s, UTextOffset start, UTextOffset *pi, UChar32 c, UBool strict);
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U_CAPI UTextOffset U_EXPORT2
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utf8_back1SafeBody(const uint8_t *s, UTextOffset start, UTextOffset i);
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/*
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* For the semantics of all of these macros, see utf16.h.
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* The UTF-8 macros favor sequences more the shorter they are.
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* Sometimes, only the single-byte case is covered by a macro,
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* while longer sequences are handled by a function call.
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*/
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/* single-code point definitions -------------------------------------------- */
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/* classes of code unit values */
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#define UTF8_IS_SINGLE(uchar) (((uchar)&0x80)==0)
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#define UTF8_IS_LEAD(uchar) ((uint8_t)((uchar)-0xc0)<0x3e)
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#define UTF8_IS_TRAIL(uchar) (((uchar)&0xc0)==0x80)
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/* number of code units per code point */
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#define UTF8_NEED_MULTIPLE_UCHAR(c) ((uint32_t)(c)>0x7f)
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/*
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* ICU does not deal with code points >0x10ffff
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* unless necessary for advancing in the byte stream.
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*
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* These length macros take into account that for values >0x10ffff
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* the "safe" append macros would write the error code point 0xffff
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* with 3 bytes.
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* Code point comparisons need to be in uint32_t because UChar32
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* may be a signed type, and negative values must be recognized.
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*/
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#if 1
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# define UTF8_CHAR_LENGTH(c) \
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((uint32_t)(c)<=0x7f ? 1 : \
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((uint32_t)(c)<=0x7ff ? 2 : \
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((uint32_t)((c)-0x10000)>0xfffff ? 3 : 4) \
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) \
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)
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#else
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# define UTF8_CHAR_LENGTH(c) \
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((uint32_t)(c)<=0x7f ? 1 : \
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((uint32_t)(c)<=0x7ff ? 2 : \
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((uint32_t)(c)<=0xffff ? 3 : \
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((uint32_t)(c)<=0x10ffff ? 4 : \
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((uint32_t)(c)<=0x3ffffff ? 5 : \
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((uint32_t)(c)<=0x7fffffff ? 6 : 3) \
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) \
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) \
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) \
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) \
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)
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#endif
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#define UTF8_MAX_CHAR_LENGTH 4
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/* average number of code units compared to UTF-16 */
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#define UTF8_ARRAY_SIZE(size) ((5*(size))/2)
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#define UTF8_GET_CHAR_UNSAFE(s, i, c) { \
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UTextOffset __I=(UTextOffset)(i); \
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UTF8_SET_CHAR_START_UNSAFE(s, __I); \
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UTF8_NEXT_CHAR_UNSAFE(s, __I, c); \
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}
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#define UTF8_GET_CHAR_SAFE(s, start, i, length, c, strict) { \
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UTextOffset __I=(UTextOffset)(i); \
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UTF8_SET_CHAR_START_SAFE(s, start, __I); \
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UTF8_NEXT_CHAR_SAFE(s, __I, length, c, strict); \
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}
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/* definitions with forward iteration --------------------------------------- */
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/*
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* Read a Unicode scalar value from an array of UTF-8 bytes.
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* Only values <=0x10ffff are accepted, and if an error occurs,
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* then c will be set such that UTF_IS_ERROR(c).
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* The _UNSAFE macro is fast and does not check for errors.
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* The _SAFE macro checks for errors and optionally for
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* irregular sequences, too, i.e., for sequences that
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* are longer than necessary, such as <c0 80> instead of <0>.
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* The strict checks also check for surrogates and
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* for 0xXXXXfffe and 0xXXXXffff.
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*/
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#define UTF8_NEXT_CHAR_UNSAFE(s, i, c) { \
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(c)=(s)[(i)++]; \
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if((uint8_t)((c)-0xc0)<0x35) { \
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uint8_t __count=UTF8_COUNT_TRAIL_BYTES(c); \
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UTF8_MASK_LEAD_BYTE(c, __count); \
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switch(__count) { \
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/* each following branch falls through to the next one */ \
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case 3: \
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(c)=((c)<<6)|((s)[(i)++]&0x3f); \
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case 2: \
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(c)=((c)<<6)|((s)[(i)++]&0x3f); \
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case 1: \
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(c)=((c)<<6)|((s)[(i)++]&0x3f); \
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/* no other branches to optimize switch() */ \
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break; \
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} \
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} \
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}
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#define UTF8_APPEND_CHAR_UNSAFE(s, i, c) { \
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if((uint32_t)(c)<=0x7f) { \
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(s)[(i)++]=(uint8_t)(c); \
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} else { \
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if((uint32_t)(c)<=0x7ff) { \
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(s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); \
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} else { \
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if((uint32_t)(c)<=0xffff) { \
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(s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); \
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} else { \
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(s)[(i)++]=(uint8_t)(((c)>>18)|0xf0); \
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(s)[(i)++]=(uint8_t)((((c)>>12)&0x3f)|0x80); \
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} \
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(s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); \
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} \
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(s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); \
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} \
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}
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#define UTF8_FWD_1_UNSAFE(s, i) { \
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(i)+=1+UTF8_COUNT_TRAIL_BYTES((s)[i]); \
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}
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#define UTF8_FWD_N_UNSAFE(s, i, n) { \
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UTextOffset __N=(n); \
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while(__N>0) { \
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UTF8_FWD_1_UNSAFE(s, i); \
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--__N; \
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} \
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}
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#define UTF8_SET_CHAR_START_UNSAFE(s, i) { \
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while(UTF8_IS_TRAIL((s)[i])) { --(i); } \
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}
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#define UTF8_NEXT_CHAR_SAFE(s, i, length, c, strict) { \
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(c)=(s)[(i)++]; \
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if(UTF8_IS_LEAD(c)) { \
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(c)=utf8_nextCharSafeBody(s, &(i), (UTextOffset)(length), c, strict); \
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} \
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}
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#define UTF8_APPEND_CHAR_SAFE(s, i, length, c) { \
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if((uint32_t)(c)<=0x7f) { \
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(s)[(i)++]=(uint8_t)(c); \
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} else { \
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(i)=utf8_appendCharSafeBody(s, (UTextOffset)(i), (UTextOffset)(length), c); \
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} \
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}
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#define UTF8_FWD_1_SAFE(s, i, length) { \
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uint8_t __b=(s)[(i)++]; \
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if(UTF8_IS_LEAD(__b)) { \
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uint8_t __count=UTF8_COUNT_TRAIL_BYTES(__b); \
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if((i)+__count>(length)) { \
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__count=(uint8_t)((length)-(i)); \
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} \
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while(__count>0 && UTF8_IS_TRAIL((s)[i])) { \
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++(i); \
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--__count; \
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} \
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} \
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}
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#define UTF8_FWD_N_SAFE(s, i, length, n) { \
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UTextOffset __N=(n); \
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while(__N>0 && (i)<(length)) { \
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UTF8_FWD_1_SAFE(s, i, length); \
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--__N; \
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} \
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}
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#define UTF8_SET_CHAR_START_SAFE(s, start, i) { \
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if(UTF8_IS_TRAIL((s)[(i)])) { \
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(i)=utf8_back1SafeBody(s, start, (UTextOffset)(i)); \
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} \
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}
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/* definitions with backward iteration -------------------------------------- */
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#define UTF8_PREV_CHAR_UNSAFE(s, i, c) { \
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(c)=(s)[--(i)]; \
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if(UTF8_IS_TRAIL(c)) { \
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uint8_t __b, __count=1, __shift=6; \
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\
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/* c is a trail byte */ \
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(c)&=0x3f; \
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for(;;) { \
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__b=(s)[--(i)]; \
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if(__b>=0xc0) { \
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UTF8_MASK_LEAD_BYTE(__b, __count); \
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(c)|=(UChar32)__b<<__shift; \
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break; \
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} else { \
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(c)|=(UChar32)(__b&0x3f)<<__shift; \
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++__count; \
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__shift+=6; \
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} \
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} \
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} \
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}
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#define UTF8_BACK_1_UNSAFE(s, i) { \
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while(UTF8_IS_TRAIL((s)[--(i)])) {} \
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}
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#define UTF8_BACK_N_UNSAFE(s, i, n) { \
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UTextOffset __N=(n); \
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while(__N>0) { \
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UTF8_BACK_1_UNSAFE(s, i); \
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--__N; \
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} \
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}
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#define UTF8_SET_CHAR_LIMIT_UNSAFE(s, i) { \
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UTF8_BACK_1_UNSAFE(s, i); \
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UTF8_FWD_1_UNSAFE(s, i); \
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}
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#define UTF8_PREV_CHAR_SAFE(s, start, i, c, strict) { \
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(c)=(s)[--(i)]; \
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if(UTF8_IS_TRAIL((c))) { \
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(c)=utf8_prevCharSafeBody(s, start, &(i), c, strict); \
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} \
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}
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#define UTF8_BACK_1_SAFE(s, start, i) { \
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if(UTF8_IS_TRAIL((s)[--(i)])) { \
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(i)=utf8_back1SafeBody(s, start, (UTextOffset)(i)); \
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} \
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}
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#define UTF8_BACK_N_SAFE(s, start, i, n) { \
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UTextOffset __N=(n); \
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while(__N>0 && (i)>(start)) { \
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UTF8_BACK_1_SAFE(s, start, i); \
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--__N; \
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} \
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}
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#define UTF8_SET_CHAR_LIMIT_SAFE(s, start, i, length) { \
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if((start)<(i) && (i)<(length)) { \
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UTF8_BACK_1_SAFE(s, start, i); \
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(i)+=1+UTF8_COUNT_TRAIL_BYTES((s)[i]); \
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if((i)>(length)) { \
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(i)=(length); \
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} \
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} \
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}
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#endif
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