Lucas Eckels | dc4699f | 2012-08-06 15:22:01 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2001-2004 Unicode, Inc. |
| 3 | * |
| 4 | * Disclaimer |
| 5 | * |
| 6 | * This source code is provided as is by Unicode, Inc. No claims are |
| 7 | * made as to fitness for any particular purpose. No warranties of any |
| 8 | * kind are expressed or implied. The recipient agrees to determine |
| 9 | * applicability of information provided. If this file has been |
| 10 | * purchased on magnetic or optical media from Unicode, Inc., the |
| 11 | * sole remedy for any claim will be exchange of defective media |
| 12 | * within 90 days of receipt. |
| 13 | * |
| 14 | * Limitations on Rights to Redistribute This Code |
| 15 | * |
| 16 | * Unicode, Inc. hereby grants the right to freely use the information |
| 17 | * supplied in this file in the creation of products supporting the |
| 18 | * Unicode Standard, and to make copies of this file in any form |
| 19 | * for internal or external distribution as long as this notice |
| 20 | * remains attached. |
| 21 | */ |
| 22 | |
| 23 | /* --------------------------------------------------------------------- |
| 24 | |
| 25 | Conversions between UTF32, UTF-16, and UTF-8. Source code file. |
| 26 | Author: Mark E. Davis, 1994. |
| 27 | Rev History: Rick McGowan, fixes & updates May 2001. |
| 28 | Sept 2001: fixed const & error conditions per |
| 29 | mods suggested by S. Parent & A. Lillich. |
| 30 | June 2002: Tim Dodd added detection and handling of incomplete |
| 31 | source sequences, enhanced error detection, added casts |
| 32 | to eliminate compiler warnings. |
| 33 | July 2003: slight mods to back out aggressive FFFE detection. |
| 34 | Jan 2004: updated switches in from-UTF8 conversions. |
| 35 | Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions. |
| 36 | |
| 37 | See the header file "ConvertUTF.h" for complete documentation. |
| 38 | |
| 39 | ------------------------------------------------------------------------ */ |
| 40 | |
| 41 | |
| 42 | #include "ConvertUTF.h" |
| 43 | #ifdef CVTUTF_DEBUG |
| 44 | #include <stdio.h> |
| 45 | #endif |
| 46 | |
| 47 | static const int halfShift = 10; /* used for shifting by 10 bits */ |
| 48 | |
| 49 | static const UTF32 halfBase = 0x0010000UL; |
| 50 | static const UTF32 halfMask = 0x3FFUL; |
| 51 | |
| 52 | #define UNI_SUR_HIGH_START (UTF32)0xD800 |
| 53 | #define UNI_SUR_HIGH_END (UTF32)0xDBFF |
| 54 | #define UNI_SUR_LOW_START (UTF32)0xDC00 |
| 55 | #define UNI_SUR_LOW_END (UTF32)0xDFFF |
| 56 | #define false 0 |
| 57 | #define true 1 |
| 58 | |
| 59 | /* --------------------------------------------------------------------- */ |
| 60 | |
| 61 | ConversionResult ConvertUTF32toUTF16 ( |
| 62 | const UTF32** sourceStart, const UTF32* sourceEnd, |
| 63 | UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) { |
| 64 | ConversionResult result = conversionOK; |
| 65 | const UTF32* source = *sourceStart; |
| 66 | UTF16* target = *targetStart; |
| 67 | while (source < sourceEnd) { |
| 68 | UTF32 ch; |
| 69 | if (target >= targetEnd) { |
| 70 | result = targetExhausted; break; |
| 71 | } |
| 72 | ch = *source++; |
| 73 | if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */ |
| 74 | /* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */ |
| 75 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
| 76 | if (flags == strictConversion) { |
| 77 | --source; /* return to the illegal value itself */ |
| 78 | result = sourceIllegal; |
| 79 | break; |
| 80 | } else { |
| 81 | *target++ = UNI_REPLACEMENT_CHAR; |
| 82 | } |
| 83 | } else { |
| 84 | *target++ = (UTF16)ch; /* normal case */ |
| 85 | } |
| 86 | } else if (ch > UNI_MAX_LEGAL_UTF32) { |
| 87 | if (flags == strictConversion) { |
| 88 | result = sourceIllegal; |
| 89 | } else { |
| 90 | *target++ = UNI_REPLACEMENT_CHAR; |
| 91 | } |
| 92 | } else { |
| 93 | /* target is a character in range 0xFFFF - 0x10FFFF. */ |
| 94 | if (target + 1 >= targetEnd) { |
| 95 | --source; /* Back up source pointer! */ |
| 96 | result = targetExhausted; break; |
| 97 | } |
| 98 | ch -= halfBase; |
| 99 | *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START); |
| 100 | *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START); |
| 101 | } |
| 102 | } |
| 103 | *sourceStart = source; |
| 104 | *targetStart = target; |
| 105 | return result; |
| 106 | } |
| 107 | |
| 108 | /* --------------------------------------------------------------------- */ |
| 109 | |
| 110 | ConversionResult ConvertUTF16toUTF32 ( |
| 111 | const UTF16** sourceStart, const UTF16* sourceEnd, |
| 112 | UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) { |
| 113 | ConversionResult result = conversionOK; |
| 114 | const UTF16* source = *sourceStart; |
| 115 | UTF32* target = *targetStart; |
| 116 | UTF32 ch, ch2; |
| 117 | while (source < sourceEnd) { |
| 118 | const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */ |
| 119 | ch = *source++; |
| 120 | /* If we have a surrogate pair, convert to UTF32 first. */ |
| 121 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) { |
| 122 | /* If the 16 bits following the high surrogate are in the source buffer... */ |
| 123 | if (source < sourceEnd) { |
| 124 | ch2 = *source; |
| 125 | /* If it's a low surrogate, convert to UTF32. */ |
| 126 | if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) { |
| 127 | ch = ((ch - UNI_SUR_HIGH_START) << halfShift) |
| 128 | + (ch2 - UNI_SUR_LOW_START) + halfBase; |
| 129 | ++source; |
| 130 | } else if (flags == strictConversion) { /* it's an unpaired high surrogate */ |
| 131 | --source; /* return to the illegal value itself */ |
| 132 | result = sourceIllegal; |
| 133 | break; |
| 134 | } |
| 135 | } else { /* We don't have the 16 bits following the high surrogate. */ |
| 136 | --source; /* return to the high surrogate */ |
| 137 | result = sourceExhausted; |
| 138 | break; |
| 139 | } |
| 140 | } else if (flags == strictConversion) { |
| 141 | /* UTF-16 surrogate values are illegal in UTF-32 */ |
| 142 | if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) { |
| 143 | --source; /* return to the illegal value itself */ |
| 144 | result = sourceIllegal; |
| 145 | break; |
| 146 | } |
| 147 | } |
| 148 | if (target >= targetEnd) { |
| 149 | source = oldSource; /* Back up source pointer! */ |
| 150 | result = targetExhausted; break; |
| 151 | } |
| 152 | *target++ = ch; |
| 153 | } |
| 154 | *sourceStart = source; |
| 155 | *targetStart = target; |
| 156 | #ifdef CVTUTF_DEBUG |
| 157 | if (result == sourceIllegal) { |
| 158 | fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2); |
| 159 | fflush(stderr); |
| 160 | } |
| 161 | #endif |
| 162 | return result; |
| 163 | } |
| 164 | |
| 165 | /* --------------------------------------------------------------------- */ |
| 166 | |
| 167 | /* |
| 168 | * Index into the table below with the first byte of a UTF-8 sequence to |
| 169 | * get the number of trailing bytes that are supposed to follow it. |
| 170 | * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is |
| 171 | * left as-is for anyone who may want to do such conversion, which was |
| 172 | * allowed in earlier algorithms. |
| 173 | */ |
| 174 | static const char trailingBytesForUTF8[256] = { |
| 175 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 176 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 177 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 178 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 179 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 180 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 181 | 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, |
| 182 | 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5 |
| 183 | }; |
| 184 | |
| 185 | /* |
| 186 | * Magic values subtracted from a buffer value during UTF8 conversion. |
| 187 | * This table contains as many values as there might be trailing bytes |
| 188 | * in a UTF-8 sequence. |
| 189 | */ |
| 190 | static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL, |
| 191 | 0x03C82080UL, 0xFA082080UL, 0x82082080UL }; |
| 192 | |
| 193 | /* |
| 194 | * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed |
| 195 | * into the first byte, depending on how many bytes follow. There are |
| 196 | * as many entries in this table as there are UTF-8 sequence types. |
| 197 | * (I.e., one byte sequence, two byte... etc.). Remember that sequencs |
| 198 | * for *legal* UTF-8 will be 4 or fewer bytes total. |
| 199 | */ |
| 200 | static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC }; |
| 201 | |
| 202 | /* --------------------------------------------------------------------- */ |
| 203 | |
| 204 | /* The interface converts a whole buffer to avoid function-call overhead. |
| 205 | * Constants have been gathered. Loops & conditionals have been removed as |
| 206 | * much as possible for efficiency, in favor of drop-through switches. |
| 207 | * (See "Note A" at the bottom of the file for equivalent code.) |
| 208 | * If your compiler supports it, the "isLegalUTF8" call can be turned |
| 209 | * into an inline function. |
| 210 | */ |
| 211 | |
| 212 | /* --------------------------------------------------------------------- */ |
| 213 | |
| 214 | ConversionResult ConvertUTF16toUTF8 ( |
| 215 | const UTF16** sourceStart, const UTF16* sourceEnd, |
| 216 | UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) { |
| 217 | ConversionResult result = conversionOK; |
| 218 | const UTF16* source = *sourceStart; |
| 219 | UTF8* target = *targetStart; |
| 220 | while (source < sourceEnd) { |
| 221 | UTF32 ch; |
| 222 | unsigned short bytesToWrite = 0; |
| 223 | const UTF32 byteMask = 0xBF; |
| 224 | const UTF32 byteMark = 0x80; |
| 225 | const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */ |
| 226 | ch = *source++; |
| 227 | /* If we have a surrogate pair, convert to UTF32 first. */ |
| 228 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) { |
| 229 | /* If the 16 bits following the high surrogate are in the source buffer... */ |
| 230 | if (source < sourceEnd) { |
| 231 | UTF32 ch2 = *source; |
| 232 | /* If it's a low surrogate, convert to UTF32. */ |
| 233 | if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) { |
| 234 | ch = ((ch - UNI_SUR_HIGH_START) << halfShift) |
| 235 | + (ch2 - UNI_SUR_LOW_START) + halfBase; |
| 236 | ++source; |
| 237 | } else if (flags == strictConversion) { /* it's an unpaired high surrogate */ |
| 238 | --source; /* return to the illegal value itself */ |
| 239 | result = sourceIllegal; |
| 240 | break; |
| 241 | } |
| 242 | } else { /* We don't have the 16 bits following the high surrogate. */ |
| 243 | --source; /* return to the high surrogate */ |
| 244 | result = sourceExhausted; |
| 245 | break; |
| 246 | } |
| 247 | } else if (flags == strictConversion) { |
| 248 | /* UTF-16 surrogate values are illegal in UTF-32 */ |
| 249 | if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) { |
| 250 | --source; /* return to the illegal value itself */ |
| 251 | result = sourceIllegal; |
| 252 | break; |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | // TPN: substitute all control characters except for NULL, TAB, LF or CR |
| 257 | if (ch && (ch != (UTF32)0x09) && (ch != (UTF32)0x0a) && (ch != (UTF32)0x0d) && (ch < (UTF32)0x20) ) { |
| 258 | ch = (UTF32)0x3f; |
| 259 | } |
| 260 | // TPN: filter out byte order marks and invalid character 0xFFFF |
| 261 | if((ch == (UTF32)0xFEFF) || (ch == (UTF32)0xFFFE)|| (ch == (UTF32)0xFFFF)) { |
| 262 | continue; |
| 263 | } |
| 264 | |
| 265 | /* Figure out how many bytes the result will require */ |
| 266 | if (ch < (UTF32)0x80) { bytesToWrite = 1; |
| 267 | } else if (ch < (UTF32)0x800) { bytesToWrite = 2; |
| 268 | } else if (ch < (UTF32)0x10000) { bytesToWrite = 3; |
| 269 | } else if (ch < (UTF32)0x110000) { bytesToWrite = 4; |
| 270 | } else { bytesToWrite = 3; |
| 271 | ch = UNI_REPLACEMENT_CHAR; |
| 272 | } |
| 273 | |
| 274 | target += bytesToWrite; |
| 275 | if (target > targetEnd) { |
| 276 | source = oldSource; /* Back up source pointer! */ |
| 277 | target -= bytesToWrite; result = targetExhausted; break; |
| 278 | } |
| 279 | switch (bytesToWrite) { /* note: everything falls through. */ |
| 280 | case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
| 281 | case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
| 282 | case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
| 283 | case 1: *--target = (UTF8)(ch | firstByteMark[bytesToWrite]); |
| 284 | } |
| 285 | target += bytesToWrite; |
| 286 | } |
| 287 | *sourceStart = source; |
| 288 | *targetStart = target; |
| 289 | return result; |
| 290 | } |
| 291 | |
| 292 | /* --------------------------------------------------------------------- */ |
| 293 | |
| 294 | /* |
| 295 | * Utility routine to tell whether a sequence of bytes is legal UTF-8. |
| 296 | * This must be called with the length pre-determined by the first byte. |
| 297 | * If not calling this from ConvertUTF8to*, then the length can be set by: |
| 298 | * length = trailingBytesForUTF8[*source]+1; |
| 299 | * and the sequence is illegal right away if there aren't that many bytes |
| 300 | * available. |
| 301 | * If presented with a length > 4, this returns false. The Unicode |
| 302 | * definition of UTF-8 goes up to 4-byte sequences. |
| 303 | */ |
| 304 | |
| 305 | inline Boolean isLegalUTF8(const UTF8 *source, int length) { |
| 306 | UTF8 a; |
| 307 | const UTF8 *srcptr = source+length; |
| 308 | switch (length) { |
| 309 | default: return false; |
| 310 | /* Everything else falls through when "true"... */ |
| 311 | case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; |
| 312 | case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; |
| 313 | case 2: if ((a = (*--srcptr)) > 0xBF) return false; |
| 314 | |
| 315 | switch (*source) { |
| 316 | /* no fall-through in this inner switch */ |
| 317 | case 0xE0: if (a < 0xA0) return false; break; |
| 318 | case 0xED: if (a > 0x9F) return false; break; |
| 319 | case 0xF0: if (a < 0x90) return false; break; |
| 320 | case 0xF4: if (a > 0x8F) return false; break; |
| 321 | default: if (a < 0x80) return false; |
| 322 | } |
| 323 | |
| 324 | case 1: if (*source >= 0x80 && *source < 0xC2) return false; |
| 325 | } |
| 326 | if (*source > 0xF4) return false; |
| 327 | return true; |
| 328 | } |
| 329 | |
| 330 | /* --------------------------------------------------------------------- */ |
| 331 | |
| 332 | /* |
| 333 | * Exported function to return whether a UTF-8 sequence is legal or not. |
| 334 | * This is not used here; it's just exported. |
| 335 | */ |
| 336 | Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) { |
| 337 | int length = trailingBytesForUTF8[*source]+1; |
| 338 | if (source+length > sourceEnd) { |
| 339 | return false; |
| 340 | } |
| 341 | return isLegalUTF8(source, length); |
| 342 | } |
| 343 | |
| 344 | /* --------------------------------------------------------------------- */ |
| 345 | |
| 346 | ConversionResult ConvertUTF8toUTF16 ( |
| 347 | const UTF8** sourceStart, const UTF8* sourceEnd, |
| 348 | UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) { |
| 349 | ConversionResult result = conversionOK; |
| 350 | const UTF8* source = *sourceStart; |
| 351 | UTF16* target = *targetStart; |
| 352 | while (source < sourceEnd) { |
| 353 | UTF32 ch = 0; |
| 354 | unsigned short extraBytesToRead = trailingBytesForUTF8[*source]; |
| 355 | if (source + extraBytesToRead >= sourceEnd) { |
| 356 | result = sourceExhausted; break; |
| 357 | } |
| 358 | /* Do this check whether lenient or strict */ |
| 359 | if (! isLegalUTF8(source, extraBytesToRead+1)) { |
| 360 | result = sourceIllegal; |
| 361 | break; |
| 362 | } |
| 363 | /* |
| 364 | * The cases all fall through. See "Note A" below. |
| 365 | */ |
| 366 | switch (extraBytesToRead) { |
| 367 | case 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */ |
| 368 | case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */ |
| 369 | case 3: ch += *source++; ch <<= 6; |
| 370 | case 2: ch += *source++; ch <<= 6; |
| 371 | case 1: ch += *source++; ch <<= 6; |
| 372 | case 0: ch += *source++; |
| 373 | } |
| 374 | ch -= offsetsFromUTF8[extraBytesToRead]; |
| 375 | |
| 376 | if (target >= targetEnd) { |
| 377 | source -= (extraBytesToRead+1); /* Back up source pointer! */ |
| 378 | result = targetExhausted; break; |
| 379 | } |
| 380 | if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */ |
| 381 | /* UTF-16 surrogate values are illegal in UTF-32 */ |
| 382 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
| 383 | if (flags == strictConversion) { |
| 384 | source -= (extraBytesToRead+1); /* return to the illegal value itself */ |
| 385 | result = sourceIllegal; |
| 386 | break; |
| 387 | } else { |
| 388 | *target++ = UNI_REPLACEMENT_CHAR; |
| 389 | } |
| 390 | } else { |
| 391 | *target++ = (UTF16)ch; /* normal case */ |
| 392 | } |
| 393 | } else if (ch > UNI_MAX_UTF16) { |
| 394 | if (flags == strictConversion) { |
| 395 | result = sourceIllegal; |
| 396 | source -= (extraBytesToRead+1); /* return to the start */ |
| 397 | break; /* Bail out; shouldn't continue */ |
| 398 | } else { |
| 399 | *target++ = UNI_REPLACEMENT_CHAR; |
| 400 | } |
| 401 | } else { |
| 402 | /* target is a character in range 0xFFFF - 0x10FFFF. */ |
| 403 | if (target + 1 >= targetEnd) { |
| 404 | source -= (extraBytesToRead+1); /* Back up source pointer! */ |
| 405 | result = targetExhausted; break; |
| 406 | } |
| 407 | ch -= halfBase; |
| 408 | *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START); |
| 409 | *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START); |
| 410 | } |
| 411 | } |
| 412 | *sourceStart = source; |
| 413 | *targetStart = target; |
| 414 | return result; |
| 415 | } |
| 416 | |
| 417 | /* --------------------------------------------------------------------- */ |
| 418 | |
| 419 | ConversionResult ConvertUTF32toUTF8 ( |
| 420 | const UTF32** sourceStart, const UTF32* sourceEnd, |
| 421 | UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) { |
| 422 | ConversionResult result = conversionOK; |
| 423 | const UTF32* source = *sourceStart; |
| 424 | UTF8* target = *targetStart; |
| 425 | while (source < sourceEnd) { |
| 426 | UTF32 ch; |
| 427 | unsigned short bytesToWrite = 0; |
| 428 | const UTF32 byteMask = 0xBF; |
| 429 | const UTF32 byteMark = 0x80; |
| 430 | ch = *source++; |
| 431 | if (flags == strictConversion ) { |
| 432 | /* UTF-16 surrogate values are illegal in UTF-32 */ |
| 433 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
| 434 | --source; /* return to the illegal value itself */ |
| 435 | result = sourceIllegal; |
| 436 | break; |
| 437 | } |
| 438 | } |
| 439 | /* |
| 440 | * Figure out how many bytes the result will require. Turn any |
| 441 | * illegally large UTF32 things (> Plane 17) into replacement chars. |
| 442 | */ |
| 443 | if (ch < (UTF32)0x80) { bytesToWrite = 1; |
| 444 | } else if (ch < (UTF32)0x800) { bytesToWrite = 2; |
| 445 | } else if (ch < (UTF32)0x10000) { bytesToWrite = 3; |
| 446 | } else if (ch <= UNI_MAX_LEGAL_UTF32) { bytesToWrite = 4; |
| 447 | } else { bytesToWrite = 3; |
| 448 | ch = UNI_REPLACEMENT_CHAR; |
| 449 | result = sourceIllegal; |
| 450 | } |
| 451 | |
| 452 | target += bytesToWrite; |
| 453 | if (target > targetEnd) { |
| 454 | --source; /* Back up source pointer! */ |
| 455 | target -= bytesToWrite; result = targetExhausted; break; |
| 456 | } |
| 457 | switch (bytesToWrite) { /* note: everything falls through. */ |
| 458 | case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
| 459 | case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
| 460 | case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
| 461 | case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]); |
| 462 | } |
| 463 | target += bytesToWrite; |
| 464 | } |
| 465 | *sourceStart = source; |
| 466 | *targetStart = target; |
| 467 | return result; |
| 468 | } |
| 469 | |
| 470 | /* --------------------------------------------------------------------- */ |
| 471 | |
| 472 | ConversionResult ConvertUTF8toUTF32 ( |
| 473 | const UTF8** sourceStart, const UTF8* sourceEnd, |
| 474 | UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) { |
| 475 | ConversionResult result = conversionOK; |
| 476 | const UTF8* source = *sourceStart; |
| 477 | UTF32* target = *targetStart; |
| 478 | while (source < sourceEnd) { |
| 479 | UTF32 ch = 0; |
| 480 | unsigned short extraBytesToRead = trailingBytesForUTF8[*source]; |
| 481 | if (source + extraBytesToRead >= sourceEnd) { |
| 482 | result = sourceExhausted; break; |
| 483 | } |
| 484 | /* Do this check whether lenient or strict */ |
| 485 | if (! isLegalUTF8(source, extraBytesToRead+1)) { |
| 486 | result = sourceIllegal; |
| 487 | break; |
| 488 | } |
| 489 | /* |
| 490 | * The cases all fall through. See "Note A" below. |
| 491 | */ |
| 492 | switch (extraBytesToRead) { |
| 493 | case 5: ch += *source++; ch <<= 6; |
| 494 | case 4: ch += *source++; ch <<= 6; |
| 495 | case 3: ch += *source++; ch <<= 6; |
| 496 | case 2: ch += *source++; ch <<= 6; |
| 497 | case 1: ch += *source++; ch <<= 6; |
| 498 | case 0: ch += *source++; |
| 499 | } |
| 500 | ch -= offsetsFromUTF8[extraBytesToRead]; |
| 501 | |
| 502 | if (target >= targetEnd) { |
| 503 | source -= (extraBytesToRead+1); /* Back up the source pointer! */ |
| 504 | result = targetExhausted; break; |
| 505 | } |
| 506 | if (ch <= UNI_MAX_LEGAL_UTF32) { |
| 507 | /* |
| 508 | * UTF-16 surrogate values are illegal in UTF-32, and anything |
| 509 | * over Plane 17 (> 0x10FFFF) is illegal. |
| 510 | */ |
| 511 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
| 512 | if (flags == strictConversion) { |
| 513 | source -= (extraBytesToRead+1); /* return to the illegal value itself */ |
| 514 | result = sourceIllegal; |
| 515 | break; |
| 516 | } else { |
| 517 | *target++ = UNI_REPLACEMENT_CHAR; |
| 518 | } |
| 519 | } else { |
| 520 | *target++ = ch; |
| 521 | } |
| 522 | } else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */ |
| 523 | result = sourceIllegal; |
| 524 | *target++ = UNI_REPLACEMENT_CHAR; |
| 525 | } |
| 526 | } |
| 527 | *sourceStart = source; |
| 528 | *targetStart = target; |
| 529 | return result; |
| 530 | } |
| 531 | |
| 532 | /* --------------------------------------------------------------------- |
| 533 | |
| 534 | Note A. |
| 535 | The fall-through switches in UTF-8 reading code save a |
| 536 | temp variable, some decrements & conditionals. The switches |
| 537 | are equivalent to the following loop: |
| 538 | { |
| 539 | int tmpBytesToRead = extraBytesToRead+1; |
| 540 | do { |
| 541 | ch += *source++; |
| 542 | --tmpBytesToRead; |
| 543 | if (tmpBytesToRead) ch <<= 6; |
| 544 | } while (tmpBytesToRead > 0); |
| 545 | } |
| 546 | In UTF-8 writing code, the switches on "bytesToWrite" are |
| 547 | similarly unrolled loops. |
| 548 | |
| 549 | --------------------------------------------------------------------- */ |