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utf8.h

00001 /*
00002 *******************************************************************************
00003 *
00004 *   Copyright (C) 1999-2000, International Business Machines
00005 *   Corporation and others.  All Rights Reserved.
00006 *
00007 *******************************************************************************
00008 *   file name:  utf8.h
00009 *   encoding:   US-ASCII
00010 *   tab size:   8 (not used)
00011 *   indentation:4
00012 *
00013 *   created on: 1999sep13
00014 *   created by: Markus W. Scherer
00015 *
00016 *   This file defines macros to deal with UTF-8 code units and code points.
00017 *   Signatures and semantics are the same as for the similarly named macros
00018 *   in utf16.h.
00019 *   utf8.h is included by utf.h after unicode/umachine.h
00020 *   and some common definitions.
00021 */
00022 
00023 
00024 /* utf.h must be included first. */
00025 #ifndef __UTF_H__
00026 # include "unicode/utf.h"
00027 #endif
00028 
00029 #ifndef __UTF8_H__
00030 #define __UTF8_H__
00031 
00032 /* internal definitions ----------------------------------------------------- */
00033 
00034 #ifdef U_UTF8_IMPL
00035 U_CAPI  uint8_t U_EXPORT2 
00036 utf8_countTrailBytes[256];
00037 #else
00038 U_CFUNC uint8_t /* U_IMPORT2? */ U_IMPORT
00039 utf8_countTrailBytes[256];
00040 #endif
00041 
00042 /*
00043  * Count the trail bytes for a lead byte -
00044  * this macro should be used so that the assembler code
00045  * that is mentioned in utf_impl.c could be used here.
00046  */
00047 #define UTF8_COUNT_TRAIL_BYTES(leadByte) (utf8_countTrailBytes[(uint8_t)leadByte])
00048 
00049 /* use a macro here, too - there may be a simpler way with some machines */
00050 #define UTF8_MASK_LEAD_BYTE(leadByte, countTrailBytes) ((leadByte)&=(1<<(6-(countTrailBytes)))-1)
00051 
00052 U_CAPI UChar32 U_EXPORT2
00053 utf8_nextCharSafeBody(const uint8_t *s, UTextOffset *pi, UTextOffset length, UChar32 c, UBool strict);
00054 
00055 U_CAPI UTextOffset U_EXPORT2
00056 utf8_appendCharSafeBody(uint8_t *s, UTextOffset i, UTextOffset length, UChar32 c);
00057 
00058 U_CAPI UChar32 U_EXPORT2
00059 utf8_prevCharSafeBody(const uint8_t *s, UTextOffset start, UTextOffset *pi, UChar32 c, UBool strict);
00060 
00061 U_CAPI UTextOffset U_EXPORT2
00062 utf8_back1SafeBody(const uint8_t *s, UTextOffset start, UTextOffset i);
00063 
00064 /*
00065  * For the semantics of all of these macros, see utf16.h.
00066  * The UTF-8 macros favor sequences more the shorter they are.
00067  * Sometimes, only the single-byte case is covered by a macro,
00068  * while longer sequences are handled by a function call.
00069  */
00070 
00071 /* single-code point definitions -------------------------------------------- */
00072 
00073 /* classes of code unit values */
00074 #define UTF8_IS_SINGLE(uchar) (((uchar)&0x80)==0)
00075 #define UTF8_IS_LEAD(uchar) ((uint8_t)((uchar)-0xc0)<0x3e)
00076 #define UTF8_IS_TRAIL(uchar) (((uchar)&0xc0)==0x80)
00077 
00078 /* number of code units per code point */
00079 #define UTF8_NEED_MULTIPLE_UCHAR(c) ((uint32_t)(c)>0x7f)
00080 
00081 /*
00082  * ICU does not deal with code points >0x10ffff
00083  * unless necessary for advancing in the byte stream.
00084  *
00085  * These length macros take into account that for values >0x10ffff
00086  * the "safe" append macros would write the error code point 0xffff
00087  * with 3 bytes.
00088  * Code point comparisons need to be in uint32_t because UChar32
00089  * may be a signed type, and negative values must be recognized.
00090  */
00091 #if 1
00092 #   define UTF8_CHAR_LENGTH(c) \
00093         ((uint32_t)(c)<=0x7f ? 1 : \
00094             ((uint32_t)(c)<=0x7ff ? 2 : \
00095                 ((uint32_t)((c)-0x10000)>0xfffff ? 3 : 4) \
00096             ) \
00097         )
00098 #else
00099 #   define UTF8_CHAR_LENGTH(c) \
00100         ((uint32_t)(c)<=0x7f ? 1 : \
00101             ((uint32_t)(c)<=0x7ff ? 2 : \
00102                 ((uint32_t)(c)<=0xffff ? 3 : \
00103                     ((uint32_t)(c)<=0x10ffff ? 4 : \
00104                         ((uint32_t)(c)<=0x3ffffff ? 5 : \
00105                             ((uint32_t)(c)<=0x7fffffff ? 6 : 3) \
00106                         ) \
00107                     ) \
00108                 ) \
00109             ) \
00110         )
00111 #endif
00112 
00113 #define UTF8_MAX_CHAR_LENGTH 4
00114 
00115 /* average number of code units compared to UTF-16 */
00116 #define UTF8_ARRAY_SIZE(size) ((5*(size))/2)
00117 
00118 #define UTF8_GET_CHAR_UNSAFE(s, i, c) { \
00119     UTextOffset __I=(UTextOffset)(i); \
00120     UTF8_SET_CHAR_START_UNSAFE(s, __I); \
00121     UTF8_NEXT_CHAR_UNSAFE(s, __I, c); \
00122 }
00123 
00124 #define UTF8_GET_CHAR_SAFE(s, start, i, length, c, strict) { \
00125     UTextOffset __I=(UTextOffset)(i); \
00126     UTF8_SET_CHAR_START_SAFE(s, start, __I); \
00127     UTF8_NEXT_CHAR_SAFE(s, __I, length, c, strict); \
00128 }
00129 
00130 /* definitions with forward iteration --------------------------------------- */
00131 
00132 /*
00133  * Read a Unicode scalar value from an array of UTF-8 bytes.
00134  * Only values <=0x10ffff are accepted, and if an error occurs,
00135  * then c will be set such that UTF_IS_ERROR(c).
00136  * The _UNSAFE macro is fast and does not check for errors.
00137  * The _SAFE macro checks for errors and optionally for
00138  * irregular sequences, too, i.e., for sequences that
00139  * are longer than necessary, such as <c0 80> instead of <0>.
00140  * The strict checks also check for surrogates and
00141  * for 0xXXXXfffe and 0xXXXXffff.
00142  */
00143 #define UTF8_NEXT_CHAR_UNSAFE(s, i, c) { \
00144     (c)=(s)[(i)++]; \
00145     if((uint8_t)((c)-0xc0)<0x35) { \
00146         uint8_t __count=UTF8_COUNT_TRAIL_BYTES(c); \
00147         UTF8_MASK_LEAD_BYTE(c, __count); \
00148         switch(__count) { \
00149         /* each following branch falls through to the next one */ \
00150         case 3: \
00151             (c)=((c)<<6)|((s)[(i)++]&0x3f); \
00152         case 2: \
00153             (c)=((c)<<6)|((s)[(i)++]&0x3f); \
00154         case 1: \
00155             (c)=((c)<<6)|((s)[(i)++]&0x3f); \
00156         /* no other branches to optimize switch() */ \
00157             break; \
00158         } \
00159     } \
00160 }
00161 
00162 #define UTF8_APPEND_CHAR_UNSAFE(s, i, c) { \
00163     if((uint32_t)(c)<=0x7f) { \
00164         (s)[(i)++]=(uint8_t)(c); \
00165     } else { \
00166         if((uint32_t)(c)<=0x7ff) { \
00167             (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); \
00168         } else { \
00169             if((uint32_t)(c)<=0xffff) { \
00170                 (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); \
00171             } else { \
00172                 (s)[(i)++]=(uint8_t)(((c)>>18)|0xf0); \
00173                 (s)[(i)++]=(uint8_t)(((c)>>12)&0x3f|0x80); \
00174             } \
00175             (s)[(i)++]=(uint8_t)(((c)>>6)&0x3f|0x80); \
00176         } \
00177         (s)[(i)++]=(uint8_t)((c)&0x3f|0x80); \
00178     } \
00179 }
00180 
00181 #define UTF8_FWD_1_UNSAFE(s, i) { \
00182     (i)+=1+UTF8_COUNT_TRAIL_BYTES((s)[i]); \
00183 }
00184 
00185 #define UTF8_FWD_N_UNSAFE(s, i, n) { \
00186     UTextOffset __N=(n); \
00187     while(__N>0) { \
00188         UTF8_FWD_1_UNSAFE(s, i); \
00189         --__N; \
00190     } \
00191 }
00192 
00193 #define UTF8_SET_CHAR_START_UNSAFE(s, i) { \
00194     while(UTF8_IS_TRAIL((s)[i])) { --(i); } \
00195 }
00196 
00197 #define UTF8_NEXT_CHAR_SAFE(s, i, length, c, strict) { \
00198     (c)=(s)[(i)++]; \
00199     if(UTF8_IS_LEAD(c)) { \
00200         (c)=utf8_nextCharSafeBody(s, &(i), (UTextOffset)(length), c, strict); \
00201     } \
00202 }
00203 
00204 #define UTF8_APPEND_CHAR_SAFE(s, i, length, c) { \
00205     if((uint32_t)(c)<=0x7f) { \
00206         (s)[(i)++]=(uint8_t)(c); \
00207     } else { \
00208         (i)=utf8_appendCharSafeBody(s, (UTextOffset)(i), (UTextOffset)(length), c); \
00209     } \
00210 }
00211 
00212 #define UTF8_FWD_1_SAFE(s, i, length) { \
00213     uint8_t __b=(s)[(i)++]; \
00214     if(UTF8_IS_LEAD(__b)) { \
00215         uint8_t __count=UTF8_COUNT_TRAIL_BYTES(__b); \
00216         if((i)+__count>(length)) { \
00217             __count=(length)-(i); \
00218         } \
00219         while(__count>0 && UTF8_IS_TRAIL((s)[i])) { \
00220             ++(i); \
00221             --__count; \
00222         } \
00223     } \
00224 }
00225 
00226 #define UTF8_FWD_N_SAFE(s, i, length, n) { \
00227     UTextOffset __N=(n); \
00228     while(__N>0 && (i)<(length)) { \
00229         UTF8_FWD_1_SAFE(s, i, length); \
00230         --__N; \
00231     } \
00232 }
00233 
00234 #define UTF8_SET_CHAR_START_SAFE(s, start, i) { \
00235     if(UTF8_IS_TRAIL((s)[(i)])) { \
00236         (i)=utf8_back1SafeBody(s, start, (UTextOffset)(i)); \
00237     } \
00238 }
00239 
00240 /* definitions with backward iteration -------------------------------------- */
00241 
00242 #define UTF8_PREV_CHAR_UNSAFE(s, i, c) { \
00243     (c)=(s)[--(i)]; \
00244     if(UTF8_IS_TRAIL(c)) { \
00245         uint8_t __b, __count=1, __shift=6; \
00246 \
00247         /* c is a trail byte */ \
00248         (c)&=0x3f; \
00249         for(;;) { \
00250             __b=(s)[--(i)]; \
00251             if(__b>=0xc0) { \
00252                 UTF8_MASK_LEAD_BYTE(__b, __count); \
00253                 (c)|=(UChar32)__b<<__shift; \
00254                 break; \
00255             } else { \
00256                 (c)|=(UChar32)(__b&0x3f)<<__shift; \
00257                 ++__count; \
00258                 __shift+=6; \
00259             } \
00260         } \
00261     } \
00262 }
00263 
00264 #define UTF8_BACK_1_UNSAFE(s, i) { \
00265     while(UTF8_IS_TRAIL((s)[--(i)])) {} \
00266 }
00267 
00268 #define UTF8_BACK_N_UNSAFE(s, i, n) { \
00269     UTextOffset __N=(n); \
00270     while(__N>0) { \
00271         UTF8_BACK_1_UNSAFE(s, i); \
00272         --__N; \
00273     } \
00274 }
00275 
00276 #define UTF8_SET_CHAR_LIMIT_UNSAFE(s, i) { \
00277     UTF8_BACK_1_UNSAFE(s, i); \
00278     UTF8_FWD_1_UNSAFE(s, i); \
00279 }
00280 
00281 #define UTF8_PREV_CHAR_SAFE(s, start, i, c, strict) { \
00282     (c)=(s)[--(i)]; \
00283     if(UTF8_IS_TRAIL((c))) { \
00284         (c)=utf8_prevCharSafeBody(s, start, &(i), c, strict); \
00285     } \
00286 }
00287 
00288 #define UTF8_BACK_1_SAFE(s, start, i) { \
00289     if(UTF8_IS_TRAIL((s)[--(i)])) { \
00290         (i)=utf8_back1SafeBody(s, start, (UTextOffset)(i)); \
00291     } \
00292 }
00293 
00294 #define UTF8_BACK_N_SAFE(s, start, i, n) { \
00295     UTextOffset __N=(n); \
00296     while(__N>0 && (i)>(start)) { \
00297         UTF8_BACK_1_SAFE(s, start, i); \
00298         --__N; \
00299     } \
00300 }
00301 
00302 #define UTF8_SET_CHAR_LIMIT_SAFE(s, start, i, length) { \
00303     if((start)<(i) && (i)<(length)) { \
00304         UTF8_BACK_1_SAFE(s, start, i); \
00305         (i)+=1+UTF8_COUNT_TRAIL_BYTES((s)[i]); \
00306         if((i)>(length)) { \
00307             (i)=(length); \
00308         } \
00309     } \
00310 }
00311 
00312 #endif

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