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comparison: intl/icu/source/common/utf_impl.c
intl/icu/source/common/utf_impl.c
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| -1:000000000000 | 0:b2c0593274f0 |
|---|---|
| 1 /* | |
| 2 ****************************************************************************** | |
| 3 * | |
| 4 * Copyright (C) 1999-2012, International Business Machines | |
| 5 * Corporation and others. All Rights Reserved. | |
| 6 * | |
| 7 ****************************************************************************** | |
| 8 * file name: utf_impl.c | |
| 9 * encoding: US-ASCII | |
| 10 * tab size: 8 (not used) | |
| 11 * indentation:4 | |
| 12 * | |
| 13 * created on: 1999sep13 | |
| 14 * created by: Markus W. Scherer | |
| 15 * | |
| 16 * This file provides implementation functions for macros in the utfXX.h | |
| 17 * that would otherwise be too long as macros. | |
| 18 */ | |
| 19 | |
| 20 /* set import/export definitions */ | |
| 21 #ifndef U_UTF8_IMPL | |
| 22 # define U_UTF8_IMPL | |
| 23 #endif | |
| 24 | |
| 25 #include "unicode/utypes.h" | |
| 26 #include "unicode/utf.h" | |
| 27 #include "unicode/utf8.h" | |
| 28 #include "unicode/utf_old.h" | |
| 29 #include "uassert.h" | |
| 30 | |
| 31 /* | |
| 32 * This table could be replaced on many machines by | |
| 33 * a few lines of assembler code using an | |
| 34 * "index of first 0-bit from msb" instruction and | |
| 35 * one or two more integer instructions. | |
| 36 * | |
| 37 * For example, on an i386, do something like | |
| 38 * - MOV AL, leadByte | |
| 39 * - NOT AL (8-bit, leave b15..b8==0..0, reverse only b7..b0) | |
| 40 * - MOV AH, 0 | |
| 41 * - BSR BX, AX (16-bit) | |
| 42 * - MOV AX, 6 (result) | |
| 43 * - JZ finish (ZF==1 if leadByte==0xff) | |
| 44 * - SUB AX, BX (result) | |
| 45 * -finish: | |
| 46 * (BSR: Bit Scan Reverse, scans for a 1-bit, starting from the MSB) | |
| 47 * | |
| 48 * In Unicode, all UTF-8 byte sequences with more than 4 bytes are illegal; | |
| 49 * lead bytes above 0xf4 are illegal. | |
| 50 * We keep them in this table for skipping long ISO 10646-UTF-8 sequences. | |
| 51 */ | |
| 52 U_EXPORT const uint8_t | |
| 53 utf8_countTrailBytes[256]={ | |
| 54 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 55 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 56 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 57 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 58 | |
| 59 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 60 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 61 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 62 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 63 | |
| 64 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 65 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 66 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 67 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 68 | |
| 69 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | |
| 70 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | |
| 71 | |
| 72 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, | |
| 73 3, 3, 3, 3, 3, | |
| 74 3, 3, 3, /* illegal in Unicode */ | |
| 75 4, 4, 4, 4, /* illegal in Unicode */ | |
| 76 5, 5, /* illegal in Unicode */ | |
| 77 0, 0 /* illegal bytes 0xfe and 0xff */ | |
| 78 }; | |
| 79 | |
| 80 static const UChar32 | |
| 81 utf8_minLegal[4]={ 0, 0x80, 0x800, 0x10000 }; | |
| 82 | |
| 83 static const UChar32 | |
| 84 utf8_errorValue[6]={ | |
| 85 UTF8_ERROR_VALUE_1, UTF8_ERROR_VALUE_2, UTF_ERROR_VALUE, 0x10ffff, | |
| 86 0x3ffffff, 0x7fffffff | |
| 87 }; | |
| 88 | |
| 89 static UChar32 | |
| 90 errorValue(int32_t count, int8_t strict) { | |
| 91 if(strict>=0) { | |
| 92 return utf8_errorValue[count]; | |
| 93 } else if(strict==-3) { | |
| 94 return 0xfffd; | |
| 95 } else { | |
| 96 return U_SENTINEL; | |
| 97 } | |
| 98 } | |
| 99 | |
| 100 /* | |
| 101 * Handle the non-inline part of the U8_NEXT() and U8_NEXT_FFFD() macros | |
| 102 * and their obsolete sibling UTF8_NEXT_CHAR_SAFE(). | |
| 103 * | |
| 104 * U8_NEXT() supports NUL-terminated strings indicated via length<0. | |
| 105 * | |
| 106 * The "strict" parameter controls the error behavior: | |
| 107 * <0 "Safe" behavior of U8_NEXT(): | |
| 108 * -1: All illegal byte sequences yield U_SENTINEL=-1. | |
| 109 * -2: Same as -1, except for lenient treatment of surrogate code points as legal. | |
| 110 * Some implementations use this for roundtripping of | |
| 111 * Unicode 16-bit strings that are not well-formed UTF-16, that is, they | |
| 112 * contain unpaired surrogates. | |
| 113 * -3: All illegal byte sequences yield U+FFFD. | |
| 114 * 0 Obsolete "safe" behavior of UTF8_NEXT_CHAR_SAFE(..., FALSE): | |
| 115 * All illegal byte sequences yield a positive code point such that this | |
| 116 * result code point would be encoded with the same number of bytes as | |
| 117 * the illegal sequence. | |
| 118 * >0 Obsolete "strict" behavior of UTF8_NEXT_CHAR_SAFE(..., TRUE): | |
| 119 * Same as the obsolete "safe" behavior, but non-characters are also treated | |
| 120 * like illegal sequences. | |
| 121 * | |
| 122 * Note that a UBool is the same as an int8_t. | |
| 123 */ | |
| 124 U_CAPI UChar32 U_EXPORT2 | |
| 125 utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict) { | |
| 126 int32_t i=*pi; | |
| 127 uint8_t count=U8_COUNT_TRAIL_BYTES(c); | |
| 128 U_ASSERT(count <= 5); /* U8_COUNT_TRAIL_BYTES returns value 0...5 */ | |
| 129 if(i+count<=length || length<0) { | |
| 130 uint8_t trail; | |
| 131 | |
| 132 U8_MASK_LEAD_BYTE(c, count); | |
| 133 /* support NUL-terminated strings: do not read beyond the first non-trail byte */ | |
| 134 switch(count) { | |
| 135 /* each branch falls through to the next one */ | |
| 136 case 0: | |
| 137 /* count==0 for illegally leading trail bytes and the illegal bytes 0xfe and 0xff */ | |
| 138 case 5: | |
| 139 case 4: | |
| 140 /* count>=4 is always illegal: no more than 3 trail bytes in Unicode's UTF-8 */ | |
| 141 break; | |
| 142 case 3: | |
| 143 trail=s[i++]-0x80; | |
| 144 c=(c<<6)|trail; | |
| 145 /* c>=0x110 would result in code point>0x10ffff, outside Unicode */ | |
| 146 if(c>=0x110 || trail>0x3f) { break; } | |
| 147 case 2: | |
| 148 trail=s[i++]-0x80; | |
| 149 c=(c<<6)|trail; | |
| 150 /* | |
| 151 * test for a surrogate d800..dfff unless we are lenient: | |
| 152 * before the last (c<<6), a surrogate is c=360..37f | |
| 153 */ | |
| 154 if(((c&0xffe0)==0x360 && strict!=-2) || trail>0x3f) { break; } | |
| 155 case 1: | |
| 156 trail=s[i++]-0x80; | |
| 157 c=(c<<6)|trail; | |
| 158 if(trail>0x3f) { break; } | |
| 159 /* correct sequence - all trail bytes have (b7..b6)==(10) */ | |
| 160 if(c>=utf8_minLegal[count] && | |
| 161 /* strict: forbid non-characters like U+fffe */ | |
| 162 (strict<=0 || !U_IS_UNICODE_NONCHAR(c))) { | |
| 163 *pi=i; | |
| 164 return c; | |
| 165 } | |
| 166 /* no default branch to optimize switch() - all values are covered */ | |
| 167 } | |
| 168 } else { | |
| 169 /* too few bytes left */ | |
| 170 count=length-i; | |
| 171 } | |
| 172 | |
| 173 /* error handling */ | |
| 174 i=*pi; | |
| 175 while(count>0 && U8_IS_TRAIL(s[i])) { | |
| 176 ++i; | |
| 177 --count; | |
| 178 } | |
| 179 c=errorValue(i-*pi, strict); | |
| 180 *pi=i; | |
| 181 return c; | |
| 182 } | |
| 183 | |
| 184 U_CAPI int32_t U_EXPORT2 | |
| 185 utf8_appendCharSafeBody(uint8_t *s, int32_t i, int32_t length, UChar32 c, UBool *pIsError) { | |
| 186 if((uint32_t)(c)<=0x7ff) { | |
| 187 if((i)+1<(length)) { | |
| 188 (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); | |
| 189 (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); | |
| 190 return i; | |
| 191 } | |
| 192 } else if((uint32_t)(c)<=0xffff) { | |
| 193 /* Starting with Unicode 3.2, surrogate code points must not be encoded in UTF-8. */ | |
| 194 if((i)+2<(length) && !U_IS_SURROGATE(c)) { | |
| 195 (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); | |
| 196 (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); | |
| 197 (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); | |
| 198 return i; | |
| 199 } | |
| 200 } else if((uint32_t)(c)<=0x10ffff) { | |
| 201 if((i)+3<(length)) { | |
| 202 (s)[(i)++]=(uint8_t)(((c)>>18)|0xf0); | |
| 203 (s)[(i)++]=(uint8_t)((((c)>>12)&0x3f)|0x80); | |
| 204 (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); | |
| 205 (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); | |
| 206 return i; | |
| 207 } | |
| 208 } | |
| 209 /* c>0x10ffff or not enough space, write an error value */ | |
| 210 if(pIsError!=NULL) { | |
| 211 *pIsError=TRUE; | |
| 212 } else { | |
| 213 length-=i; | |
| 214 if(length>0) { | |
| 215 int32_t offset; | |
| 216 if(length>3) { | |
| 217 length=3; | |
| 218 } | |
| 219 s+=i; | |
| 220 offset=0; | |
| 221 c=utf8_errorValue[length-1]; | |
| 222 UTF8_APPEND_CHAR_UNSAFE(s, offset, c); | |
| 223 i=i+offset; | |
| 224 } | |
| 225 } | |
| 226 return i; | |
| 227 } | |
| 228 | |
| 229 U_CAPI UChar32 U_EXPORT2 | |
| 230 utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, UBool strict) { | |
| 231 int32_t i=*pi; | |
| 232 uint8_t b, count=1, shift=6; | |
| 233 | |
| 234 if(!U8_IS_TRAIL(c)) { return errorValue(0, strict); } | |
| 235 | |
| 236 /* extract value bits from the last trail byte */ | |
| 237 c&=0x3f; | |
| 238 | |
| 239 for(;;) { | |
| 240 if(i<=start) { | |
| 241 /* no lead byte at all */ | |
| 242 return errorValue(0, strict); | |
| 243 } | |
| 244 | |
| 245 /* read another previous byte */ | |
| 246 b=s[--i]; | |
| 247 if((uint8_t)(b-0x80)<0x7e) { /* 0x80<=b<0xfe */ | |
| 248 if(b&0x40) { | |
| 249 /* lead byte, this will always end the loop */ | |
| 250 uint8_t shouldCount=U8_COUNT_TRAIL_BYTES(b); | |
| 251 | |
| 252 if(count==shouldCount) { | |
| 253 /* set the new position */ | |
| 254 *pi=i; | |
| 255 U8_MASK_LEAD_BYTE(b, count); | |
| 256 c|=(UChar32)b<<shift; | |
| 257 if(count>=4 || c>0x10ffff || c<utf8_minLegal[count] || (U_IS_SURROGATE(c) && strict!=-2) || (strict>0 && U_IS_UNICODE_NONCHAR(c))) { | |
| 258 /* illegal sequence or (strict and non-character) */ | |
| 259 if(count>=4) { | |
| 260 count=3; | |
| 261 } | |
| 262 c=errorValue(count, strict); | |
| 263 } else { | |
| 264 /* exit with correct c */ | |
| 265 } | |
| 266 } else { | |
| 267 /* the lead byte does not match the number of trail bytes */ | |
| 268 /* only set the position to the lead byte if it would | |
| 269 include the trail byte that we started with */ | |
| 270 if(count<shouldCount) { | |
| 271 *pi=i; | |
| 272 c=errorValue(count, strict); | |
| 273 } else { | |
| 274 c=errorValue(0, strict); | |
| 275 } | |
| 276 } | |
| 277 break; | |
| 278 } else if(count<5) { | |
| 279 /* trail byte */ | |
| 280 c|=(UChar32)(b&0x3f)<<shift; | |
| 281 ++count; | |
| 282 shift+=6; | |
| 283 } else { | |
| 284 /* more than 5 trail bytes is illegal */ | |
| 285 c=errorValue(0, strict); | |
| 286 break; | |
| 287 } | |
| 288 } else { | |
| 289 /* single-byte character precedes trailing bytes */ | |
| 290 c=errorValue(0, strict); | |
| 291 break; | |
| 292 } | |
| 293 } | |
| 294 return c; | |
| 295 } | |
| 296 | |
| 297 U_CAPI int32_t U_EXPORT2 | |
| 298 utf8_back1SafeBody(const uint8_t *s, int32_t start, int32_t i) { | |
| 299 /* i had been decremented once before the function call */ | |
| 300 int32_t I=i, Z; | |
| 301 uint8_t b; | |
| 302 | |
| 303 /* read at most the 6 bytes s[Z] to s[i], inclusively */ | |
| 304 if(I-5>start) { | |
| 305 Z=I-5; | |
| 306 } else { | |
| 307 Z=start; | |
| 308 } | |
| 309 | |
| 310 /* return I if the sequence starting there is long enough to include i */ | |
| 311 do { | |
| 312 b=s[I]; | |
| 313 if((uint8_t)(b-0x80)>=0x7e) { /* not 0x80<=b<0xfe */ | |
| 314 break; | |
| 315 } else if(b>=0xc0) { | |
| 316 if(U8_COUNT_TRAIL_BYTES(b)>=(i-I)) { | |
| 317 return I; | |
| 318 } else { | |
| 319 break; | |
| 320 } | |
| 321 } | |
| 322 } while(Z<=--I); | |
| 323 | |
| 324 /* return i itself to be consistent with the FWD_1 macro */ | |
| 325 return i; | |
| 326 } |
