| /*===--- ConvertUTF.c - Universal Character Names conversions ---------------=== | 
 |  * | 
 |  *                     The LLVM Compiler Infrastructure | 
 |  * | 
 |  * This file is distributed under the University of Illinois Open Source | 
 |  * License. See LICENSE.TXT for details. | 
 |  * | 
 |  *===------------------------------------------------------------------------=*/ | 
 | /* | 
 |  * Copyright 2001-2004 Unicode, Inc. | 
 |  * | 
 |  * Disclaimer | 
 |  * | 
 |  * This source code is provided as is by Unicode, Inc. No claims are | 
 |  * made as to fitness for any particular purpose. No warranties of any | 
 |  * kind are expressed or implied. The recipient agrees to determine | 
 |  * applicability of information provided. If this file has been | 
 |  * purchased on magnetic or optical media from Unicode, Inc., the | 
 |  * sole remedy for any claim will be exchange of defective media | 
 |  * within 90 days of receipt. | 
 |  * | 
 |  * Limitations on Rights to Redistribute This Code | 
 |  * | 
 |  * Unicode, Inc. hereby grants the right to freely use the information | 
 |  * supplied in this file in the creation of products supporting the | 
 |  * Unicode Standard, and to make copies of this file in any form | 
 |  * for internal or external distribution as long as this notice | 
 |  * remains attached. | 
 |  */ | 
 |  | 
 | /* --------------------------------------------------------------------- | 
 |  | 
 |     Conversions between UTF32, UTF-16, and UTF-8. Source code file. | 
 |     Author: Mark E. Davis, 1994. | 
 |     Rev History: Rick McGowan, fixes & updates May 2001. | 
 |     Sept 2001: fixed const & error conditions per | 
 |         mods suggested by S. Parent & A. Lillich. | 
 |     June 2002: Tim Dodd added detection and handling of incomplete | 
 |         source sequences, enhanced error detection, added casts | 
 |         to eliminate compiler warnings. | 
 |     July 2003: slight mods to back out aggressive FFFE detection. | 
 |     Jan 2004: updated switches in from-UTF8 conversions. | 
 |     Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions. | 
 |  | 
 |     See the header file "ConvertUTF.h" for complete documentation. | 
 |  | 
 | ------------------------------------------------------------------------ */ | 
 |  | 
 | #include "llvm/Support/ConvertUTF.h" | 
 | #ifdef CVTUTF_DEBUG | 
 | #include <stdio.h> | 
 | #endif | 
 | #include <assert.h> | 
 |  | 
 | /* | 
 |  * This code extensively uses fall-through switches. | 
 |  * Keep the compiler from warning about that. | 
 |  */ | 
 | #if defined(__clang__) && defined(__has_warning) | 
 | # if __has_warning("-Wimplicit-fallthrough") | 
 | #  define ConvertUTF_DISABLE_WARNINGS \ | 
 |     _Pragma("clang diagnostic push")  \ | 
 |     _Pragma("clang diagnostic ignored \"-Wimplicit-fallthrough\"") | 
 | #  define ConvertUTF_RESTORE_WARNINGS \ | 
 |     _Pragma("clang diagnostic pop") | 
 | # endif | 
 | #elif defined(__GNUC__) && __GNUC__ > 6 | 
 | # define ConvertUTF_DISABLE_WARNINGS \ | 
 |    _Pragma("GCC diagnostic push")    \ | 
 |    _Pragma("GCC diagnostic ignored \"-Wimplicit-fallthrough\"") | 
 | # define ConvertUTF_RESTORE_WARNINGS \ | 
 |    _Pragma("GCC diagnostic pop") | 
 | #endif | 
 | #ifndef ConvertUTF_DISABLE_WARNINGS | 
 | # define ConvertUTF_DISABLE_WARNINGS | 
 | #endif | 
 | #ifndef ConvertUTF_RESTORE_WARNINGS | 
 | # define ConvertUTF_RESTORE_WARNINGS | 
 | #endif | 
 |  | 
 | ConvertUTF_DISABLE_WARNINGS | 
 |  | 
 | namespace llvm { | 
 |  | 
 | static const int halfShift  = 10; /* used for shifting by 10 bits */ | 
 |  | 
 | static const UTF32 halfBase = 0x0010000UL; | 
 | static const UTF32 halfMask = 0x3FFUL; | 
 |  | 
 | #define UNI_SUR_HIGH_START  (UTF32)0xD800 | 
 | #define UNI_SUR_HIGH_END    (UTF32)0xDBFF | 
 | #define UNI_SUR_LOW_START   (UTF32)0xDC00 | 
 | #define UNI_SUR_LOW_END     (UTF32)0xDFFF | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | /* | 
 |  * Index into the table below with the first byte of a UTF-8 sequence to | 
 |  * get the number of trailing bytes that are supposed to follow it. | 
 |  * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is | 
 |  * left as-is for anyone who may want to do such conversion, which was | 
 |  * allowed in earlier algorithms. | 
 |  */ | 
 | static const char trailingBytesForUTF8[256] = { | 
 |     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, | 
 |     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, | 
 |     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, | 
 |     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, | 
 |     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, | 
 |     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, | 
 |     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, | 
 |     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 | 
 | }; | 
 |  | 
 | /* | 
 |  * Magic values subtracted from a buffer value during UTF8 conversion. | 
 |  * This table contains as many values as there might be trailing bytes | 
 |  * in a UTF-8 sequence. | 
 |  */ | 
 | static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL, | 
 |                      0x03C82080UL, 0xFA082080UL, 0x82082080UL }; | 
 |  | 
 | /* | 
 |  * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed | 
 |  * into the first byte, depending on how many bytes follow.  There are | 
 |  * as many entries in this table as there are UTF-8 sequence types. | 
 |  * (I.e., one byte sequence, two byte... etc.). Remember that sequencs | 
 |  * for *legal* UTF-8 will be 4 or fewer bytes total. | 
 |  */ | 
 | static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC }; | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | /* The interface converts a whole buffer to avoid function-call overhead. | 
 |  * Constants have been gathered. Loops & conditionals have been removed as | 
 |  * much as possible for efficiency, in favor of drop-through switches. | 
 |  * (See "Note A" at the bottom of the file for equivalent code.) | 
 |  * If your compiler supports it, the "isLegalUTF8" call can be turned | 
 |  * into an inline function. | 
 |  */ | 
 |  | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | ConversionResult ConvertUTF32toUTF16 ( | 
 |         const UTF32** sourceStart, const UTF32* sourceEnd, | 
 |         UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) { | 
 |     ConversionResult result = conversionOK; | 
 |     const UTF32* source = *sourceStart; | 
 |     UTF16* target = *targetStart; | 
 |     while (source < sourceEnd) { | 
 |         UTF32 ch; | 
 |         if (target >= targetEnd) { | 
 |             result = targetExhausted; break; | 
 |         } | 
 |         ch = *source++; | 
 |         if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */ | 
 |             /* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */ | 
 |             if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { | 
 |                 if (flags == strictConversion) { | 
 |                     --source; /* return to the illegal value itself */ | 
 |                     result = sourceIllegal; | 
 |                     break; | 
 |                 } else { | 
 |                     *target++ = UNI_REPLACEMENT_CHAR; | 
 |                 } | 
 |             } else { | 
 |                 *target++ = (UTF16)ch; /* normal case */ | 
 |             } | 
 |         } else if (ch > UNI_MAX_LEGAL_UTF32) { | 
 |             if (flags == strictConversion) { | 
 |                 result = sourceIllegal; | 
 |             } else { | 
 |                 *target++ = UNI_REPLACEMENT_CHAR; | 
 |             } | 
 |         } else { | 
 |             /* target is a character in range 0xFFFF - 0x10FFFF. */ | 
 |             if (target + 1 >= targetEnd) { | 
 |                 --source; /* Back up source pointer! */ | 
 |                 result = targetExhausted; break; | 
 |             } | 
 |             ch -= halfBase; | 
 |             *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START); | 
 |             *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START); | 
 |         } | 
 |     } | 
 |     *sourceStart = source; | 
 |     *targetStart = target; | 
 |     return result; | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | ConversionResult ConvertUTF16toUTF32 ( | 
 |         const UTF16** sourceStart, const UTF16* sourceEnd, | 
 |         UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) { | 
 |     ConversionResult result = conversionOK; | 
 |     const UTF16* source = *sourceStart; | 
 |     UTF32* target = *targetStart; | 
 |     UTF32 ch, ch2; | 
 |     while (source < sourceEnd) { | 
 |         const UTF16* oldSource = source; /*  In case we have to back up because of target overflow. */ | 
 |         ch = *source++; | 
 |         /* If we have a surrogate pair, convert to UTF32 first. */ | 
 |         if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) { | 
 |             /* If the 16 bits following the high surrogate are in the source buffer... */ | 
 |             if (source < sourceEnd) { | 
 |                 ch2 = *source; | 
 |                 /* If it's a low surrogate, convert to UTF32. */ | 
 |                 if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) { | 
 |                     ch = ((ch - UNI_SUR_HIGH_START) << halfShift) | 
 |                         + (ch2 - UNI_SUR_LOW_START) + halfBase; | 
 |                     ++source; | 
 |                 } else if (flags == strictConversion) { /* it's an unpaired high surrogate */ | 
 |                     --source; /* return to the illegal value itself */ | 
 |                     result = sourceIllegal; | 
 |                     break; | 
 |                 } | 
 |             } else { /* We don't have the 16 bits following the high surrogate. */ | 
 |                 --source; /* return to the high surrogate */ | 
 |                 result = sourceExhausted; | 
 |                 break; | 
 |             } | 
 |         } else if (flags == strictConversion) { | 
 |             /* UTF-16 surrogate values are illegal in UTF-32 */ | 
 |             if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) { | 
 |                 --source; /* return to the illegal value itself */ | 
 |                 result = sourceIllegal; | 
 |                 break; | 
 |             } | 
 |         } | 
 |         if (target >= targetEnd) { | 
 |             source = oldSource; /* Back up source pointer! */ | 
 |             result = targetExhausted; break; | 
 |         } | 
 |         *target++ = ch; | 
 |     } | 
 |     *sourceStart = source; | 
 |     *targetStart = target; | 
 | #ifdef CVTUTF_DEBUG | 
 | if (result == sourceIllegal) { | 
 |     fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2); | 
 |     fflush(stderr); | 
 | } | 
 | #endif | 
 |     return result; | 
 | } | 
 | ConversionResult ConvertUTF16toUTF8 ( | 
 |         const UTF16** sourceStart, const UTF16* sourceEnd, | 
 |         UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) { | 
 |     ConversionResult result = conversionOK; | 
 |     const UTF16* source = *sourceStart; | 
 |     UTF8* target = *targetStart; | 
 |     while (source < sourceEnd) { | 
 |         UTF32 ch; | 
 |         unsigned short bytesToWrite = 0; | 
 |         const UTF32 byteMask = 0xBF; | 
 |         const UTF32 byteMark = 0x80; | 
 |         const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */ | 
 |         ch = *source++; | 
 |         /* If we have a surrogate pair, convert to UTF32 first. */ | 
 |         if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) { | 
 |             /* If the 16 bits following the high surrogate are in the source buffer... */ | 
 |             if (source < sourceEnd) { | 
 |                 UTF32 ch2 = *source; | 
 |                 /* If it's a low surrogate, convert to UTF32. */ | 
 |                 if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) { | 
 |                     ch = ((ch - UNI_SUR_HIGH_START) << halfShift) | 
 |                         + (ch2 - UNI_SUR_LOW_START) + halfBase; | 
 |                     ++source; | 
 |                 } else if (flags == strictConversion) { /* it's an unpaired high surrogate */ | 
 |                     --source; /* return to the illegal value itself */ | 
 |                     result = sourceIllegal; | 
 |                     break; | 
 |                 } | 
 |             } else { /* We don't have the 16 bits following the high surrogate. */ | 
 |                 --source; /* return to the high surrogate */ | 
 |                 result = sourceExhausted; | 
 |                 break; | 
 |             } | 
 |         } else if (flags == strictConversion) { | 
 |             /* UTF-16 surrogate values are illegal in UTF-32 */ | 
 |             if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) { | 
 |                 --source; /* return to the illegal value itself */ | 
 |                 result = sourceIllegal; | 
 |                 break; | 
 |             } | 
 |         } | 
 |         /* Figure out how many bytes the result will require */ | 
 |         if (ch < (UTF32)0x80) {      bytesToWrite = 1; | 
 |         } else if (ch < (UTF32)0x800) {     bytesToWrite = 2; | 
 |         } else if (ch < (UTF32)0x10000) {   bytesToWrite = 3; | 
 |         } else if (ch < (UTF32)0x110000) {  bytesToWrite = 4; | 
 |         } else {                            bytesToWrite = 3; | 
 |                                             ch = UNI_REPLACEMENT_CHAR; | 
 |         } | 
 |  | 
 |         target += bytesToWrite; | 
 |         if (target > targetEnd) { | 
 |             source = oldSource; /* Back up source pointer! */ | 
 |             target -= bytesToWrite; result = targetExhausted; break; | 
 |         } | 
 |         switch (bytesToWrite) { /* note: everything falls through. */ | 
 |             case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; | 
 |             case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; | 
 |             case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; | 
 |             case 1: *--target =  (UTF8)(ch | firstByteMark[bytesToWrite]); | 
 |         } | 
 |         target += bytesToWrite; | 
 |     } | 
 |     *sourceStart = source; | 
 |     *targetStart = target; | 
 |     return result; | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | ConversionResult ConvertUTF32toUTF8 ( | 
 |         const UTF32** sourceStart, const UTF32* sourceEnd, | 
 |         UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) { | 
 |     ConversionResult result = conversionOK; | 
 |     const UTF32* source = *sourceStart; | 
 |     UTF8* target = *targetStart; | 
 |     while (source < sourceEnd) { | 
 |         UTF32 ch; | 
 |         unsigned short bytesToWrite = 0; | 
 |         const UTF32 byteMask = 0xBF; | 
 |         const UTF32 byteMark = 0x80; | 
 |         ch = *source++; | 
 |         if (flags == strictConversion ) { | 
 |             /* UTF-16 surrogate values are illegal in UTF-32 */ | 
 |             if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { | 
 |                 --source; /* return to the illegal value itself */ | 
 |                 result = sourceIllegal; | 
 |                 break; | 
 |             } | 
 |         } | 
 |         /* | 
 |          * Figure out how many bytes the result will require. Turn any | 
 |          * illegally large UTF32 things (> Plane 17) into replacement chars. | 
 |          */ | 
 |         if (ch < (UTF32)0x80) {      bytesToWrite = 1; | 
 |         } else if (ch < (UTF32)0x800) {     bytesToWrite = 2; | 
 |         } else if (ch < (UTF32)0x10000) {   bytesToWrite = 3; | 
 |         } else if (ch <= UNI_MAX_LEGAL_UTF32) {  bytesToWrite = 4; | 
 |         } else {                            bytesToWrite = 3; | 
 |                                             ch = UNI_REPLACEMENT_CHAR; | 
 |                                             result = sourceIllegal; | 
 |         } | 
 |  | 
 |         target += bytesToWrite; | 
 |         if (target > targetEnd) { | 
 |             --source; /* Back up source pointer! */ | 
 |             target -= bytesToWrite; result = targetExhausted; break; | 
 |         } | 
 |         switch (bytesToWrite) { /* note: everything falls through. */ | 
 |             case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; | 
 |             case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; | 
 |             case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; | 
 |             case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]); | 
 |         } | 
 |         target += bytesToWrite; | 
 |     } | 
 |     *sourceStart = source; | 
 |     *targetStart = target; | 
 |     return result; | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | /* | 
 |  * Utility routine to tell whether a sequence of bytes is legal UTF-8. | 
 |  * This must be called with the length pre-determined by the first byte. | 
 |  * If not calling this from ConvertUTF8to*, then the length can be set by: | 
 |  *  length = trailingBytesForUTF8[*source]+1; | 
 |  * and the sequence is illegal right away if there aren't that many bytes | 
 |  * available. | 
 |  * If presented with a length > 4, this returns false.  The Unicode | 
 |  * definition of UTF-8 goes up to 4-byte sequences. | 
 |  */ | 
 |  | 
 | static Boolean isLegalUTF8(const UTF8 *source, int length) { | 
 |     UTF8 a; | 
 |     const UTF8 *srcptr = source+length; | 
 |     switch (length) { | 
 |     default: return false; | 
 |         /* Everything else falls through when "true"... */ | 
 |     case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; | 
 |     case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; | 
 |     case 2: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; | 
 |  | 
 |         switch (*source) { | 
 |             /* no fall-through in this inner switch */ | 
 |             case 0xE0: if (a < 0xA0) return false; break; | 
 |             case 0xED: if (a > 0x9F) return false; break; | 
 |             case 0xF0: if (a < 0x90) return false; break; | 
 |             case 0xF4: if (a > 0x8F) return false; break; | 
 |             default:   if (a < 0x80) return false; | 
 |         } | 
 |  | 
 |     case 1: if (*source >= 0x80 && *source < 0xC2) return false; | 
 |     } | 
 |     if (*source > 0xF4) return false; | 
 |     return true; | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | /* | 
 |  * Exported function to return whether a UTF-8 sequence is legal or not. | 
 |  * This is not used here; it's just exported. | 
 |  */ | 
 | Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) { | 
 |     int length = trailingBytesForUTF8[*source]+1; | 
 |     if (length > sourceEnd - source) { | 
 |         return false; | 
 |     } | 
 |     return isLegalUTF8(source, length); | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | static unsigned | 
 | findMaximalSubpartOfIllFormedUTF8Sequence(const UTF8 *source, | 
 |                                           const UTF8 *sourceEnd) { | 
 |   UTF8 b1, b2, b3; | 
 |  | 
 |   assert(!isLegalUTF8Sequence(source, sourceEnd)); | 
 |  | 
 |   /* | 
 |    * Unicode 6.3.0, D93b: | 
 |    * | 
 |    *   Maximal subpart of an ill-formed subsequence: The longest code unit | 
 |    *   subsequence starting at an unconvertible offset that is either: | 
 |    *   a. the initial subsequence of a well-formed code unit sequence, or | 
 |    *   b. a subsequence of length one. | 
 |    */ | 
 |  | 
 |   if (source == sourceEnd) | 
 |     return 0; | 
 |  | 
 |   /* | 
 |    * Perform case analysis.  See Unicode 6.3.0, Table 3-7. Well-Formed UTF-8 | 
 |    * Byte Sequences. | 
 |    */ | 
 |  | 
 |   b1 = *source; | 
 |   ++source; | 
 |   if (b1 >= 0xC2 && b1 <= 0xDF) { | 
 |     /* | 
 |      * First byte is valid, but we know that this code unit sequence is | 
 |      * invalid, so the maximal subpart has to end after the first byte. | 
 |      */ | 
 |     return 1; | 
 |   } | 
 |  | 
 |   if (source == sourceEnd) | 
 |     return 1; | 
 |  | 
 |   b2 = *source; | 
 |   ++source; | 
 |  | 
 |   if (b1 == 0xE0) { | 
 |     return (b2 >= 0xA0 && b2 <= 0xBF) ? 2 : 1; | 
 |   } | 
 |   if (b1 >= 0xE1 && b1 <= 0xEC) { | 
 |     return (b2 >= 0x80 && b2 <= 0xBF) ? 2 : 1; | 
 |   } | 
 |   if (b1 == 0xED) { | 
 |     return (b2 >= 0x80 && b2 <= 0x9F) ? 2 : 1; | 
 |   } | 
 |   if (b1 >= 0xEE && b1 <= 0xEF) { | 
 |     return (b2 >= 0x80 && b2 <= 0xBF) ? 2 : 1; | 
 |   } | 
 |   if (b1 == 0xF0) { | 
 |     if (b2 >= 0x90 && b2 <= 0xBF) { | 
 |       if (source == sourceEnd) | 
 |         return 2; | 
 |  | 
 |       b3 = *source; | 
 |       return (b3 >= 0x80 && b3 <= 0xBF) ? 3 : 2; | 
 |     } | 
 |     return 1; | 
 |   } | 
 |   if (b1 >= 0xF1 && b1 <= 0xF3) { | 
 |     if (b2 >= 0x80 && b2 <= 0xBF) { | 
 |       if (source == sourceEnd) | 
 |         return 2; | 
 |  | 
 |       b3 = *source; | 
 |       return (b3 >= 0x80 && b3 <= 0xBF) ? 3 : 2; | 
 |     } | 
 |     return 1; | 
 |   } | 
 |   if (b1 == 0xF4) { | 
 |     if (b2 >= 0x80 && b2 <= 0x8F) { | 
 |       if (source == sourceEnd) | 
 |         return 2; | 
 |  | 
 |       b3 = *source; | 
 |       return (b3 >= 0x80 && b3 <= 0xBF) ? 3 : 2; | 
 |     } | 
 |     return 1; | 
 |   } | 
 |  | 
 |   assert((b1 >= 0x80 && b1 <= 0xC1) || b1 >= 0xF5); | 
 |   /* | 
 |    * There are no valid sequences that start with these bytes.  Maximal subpart | 
 |    * is defined to have length 1 in these cases. | 
 |    */ | 
 |   return 1; | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | /* | 
 |  * Exported function to return the total number of bytes in a codepoint | 
 |  * represented in UTF-8, given the value of the first byte. | 
 |  */ | 
 | unsigned getNumBytesForUTF8(UTF8 first) { | 
 |   return trailingBytesForUTF8[first] + 1; | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | /* | 
 |  * Exported function to return whether a UTF-8 string is legal or not. | 
 |  * This is not used here; it's just exported. | 
 |  */ | 
 | Boolean isLegalUTF8String(const UTF8 **source, const UTF8 *sourceEnd) { | 
 |     while (*source != sourceEnd) { | 
 |         int length = trailingBytesForUTF8[**source] + 1; | 
 |         if (length > sourceEnd - *source || !isLegalUTF8(*source, length)) | 
 |             return false; | 
 |         *source += length; | 
 |     } | 
 |     return true; | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | ConversionResult ConvertUTF8toUTF16 ( | 
 |         const UTF8** sourceStart, const UTF8* sourceEnd, | 
 |         UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) { | 
 |     ConversionResult result = conversionOK; | 
 |     const UTF8* source = *sourceStart; | 
 |     UTF16* target = *targetStart; | 
 |     while (source < sourceEnd) { | 
 |         UTF32 ch = 0; | 
 |         unsigned short extraBytesToRead = trailingBytesForUTF8[*source]; | 
 |         if (extraBytesToRead >= sourceEnd - source) { | 
 |             result = sourceExhausted; break; | 
 |         } | 
 |         /* Do this check whether lenient or strict */ | 
 |         if (!isLegalUTF8(source, extraBytesToRead+1)) { | 
 |             result = sourceIllegal; | 
 |             break; | 
 |         } | 
 |         /* | 
 |          * The cases all fall through. See "Note A" below. | 
 |          */ | 
 |         switch (extraBytesToRead) { | 
 |             case 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */ | 
 |             case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */ | 
 |             case 3: ch += *source++; ch <<= 6; | 
 |             case 2: ch += *source++; ch <<= 6; | 
 |             case 1: ch += *source++; ch <<= 6; | 
 |             case 0: ch += *source++; | 
 |         } | 
 |         ch -= offsetsFromUTF8[extraBytesToRead]; | 
 |  | 
 |         if (target >= targetEnd) { | 
 |             source -= (extraBytesToRead+1); /* Back up source pointer! */ | 
 |             result = targetExhausted; break; | 
 |         } | 
 |         if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */ | 
 |             /* UTF-16 surrogate values are illegal in UTF-32 */ | 
 |             if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { | 
 |                 if (flags == strictConversion) { | 
 |                     source -= (extraBytesToRead+1); /* return to the illegal value itself */ | 
 |                     result = sourceIllegal; | 
 |                     break; | 
 |                 } else { | 
 |                     *target++ = UNI_REPLACEMENT_CHAR; | 
 |                 } | 
 |             } else { | 
 |                 *target++ = (UTF16)ch; /* normal case */ | 
 |             } | 
 |         } else if (ch > UNI_MAX_UTF16) { | 
 |             if (flags == strictConversion) { | 
 |                 result = sourceIllegal; | 
 |                 source -= (extraBytesToRead+1); /* return to the start */ | 
 |                 break; /* Bail out; shouldn't continue */ | 
 |             } else { | 
 |                 *target++ = UNI_REPLACEMENT_CHAR; | 
 |             } | 
 |         } else { | 
 |             /* target is a character in range 0xFFFF - 0x10FFFF. */ | 
 |             if (target + 1 >= targetEnd) { | 
 |                 source -= (extraBytesToRead+1); /* Back up source pointer! */ | 
 |                 result = targetExhausted; break; | 
 |             } | 
 |             ch -= halfBase; | 
 |             *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START); | 
 |             *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START); | 
 |         } | 
 |     } | 
 |     *sourceStart = source; | 
 |     *targetStart = target; | 
 |     return result; | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- */ | 
 |  | 
 | static ConversionResult ConvertUTF8toUTF32Impl( | 
 |         const UTF8** sourceStart, const UTF8* sourceEnd, | 
 |         UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags, | 
 |         Boolean InputIsPartial) { | 
 |     ConversionResult result = conversionOK; | 
 |     const UTF8* source = *sourceStart; | 
 |     UTF32* target = *targetStart; | 
 |     while (source < sourceEnd) { | 
 |         UTF32 ch = 0; | 
 |         unsigned short extraBytesToRead = trailingBytesForUTF8[*source]; | 
 |         if (extraBytesToRead >= sourceEnd - source) { | 
 |             if (flags == strictConversion || InputIsPartial) { | 
 |                 result = sourceExhausted; | 
 |                 break; | 
 |             } else { | 
 |                 result = sourceIllegal; | 
 |  | 
 |                 /* | 
 |                  * Replace the maximal subpart of ill-formed sequence with | 
 |                  * replacement character. | 
 |                  */ | 
 |                 source += findMaximalSubpartOfIllFormedUTF8Sequence(source, | 
 |                                                                     sourceEnd); | 
 |                 *target++ = UNI_REPLACEMENT_CHAR; | 
 |                 continue; | 
 |             } | 
 |         } | 
 |         if (target >= targetEnd) { | 
 |             result = targetExhausted; break; | 
 |         } | 
 |  | 
 |         /* Do this check whether lenient or strict */ | 
 |         if (!isLegalUTF8(source, extraBytesToRead+1)) { | 
 |             result = sourceIllegal; | 
 |             if (flags == strictConversion) { | 
 |                 /* Abort conversion. */ | 
 |                 break; | 
 |             } else { | 
 |                 /* | 
 |                  * Replace the maximal subpart of ill-formed sequence with | 
 |                  * replacement character. | 
 |                  */ | 
 |                 source += findMaximalSubpartOfIllFormedUTF8Sequence(source, | 
 |                                                                     sourceEnd); | 
 |                 *target++ = UNI_REPLACEMENT_CHAR; | 
 |                 continue; | 
 |             } | 
 |         } | 
 |         /* | 
 |          * The cases all fall through. See "Note A" below. | 
 |          */ | 
 |         switch (extraBytesToRead) { | 
 |             case 5: ch += *source++; ch <<= 6; | 
 |             case 4: ch += *source++; ch <<= 6; | 
 |             case 3: ch += *source++; ch <<= 6; | 
 |             case 2: ch += *source++; ch <<= 6; | 
 |             case 1: ch += *source++; ch <<= 6; | 
 |             case 0: ch += *source++; | 
 |         } | 
 |         ch -= offsetsFromUTF8[extraBytesToRead]; | 
 |  | 
 |         if (ch <= UNI_MAX_LEGAL_UTF32) { | 
 |             /* | 
 |              * UTF-16 surrogate values are illegal in UTF-32, and anything | 
 |              * over Plane 17 (> 0x10FFFF) is illegal. | 
 |              */ | 
 |             if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { | 
 |                 if (flags == strictConversion) { | 
 |                     source -= (extraBytesToRead+1); /* return to the illegal value itself */ | 
 |                     result = sourceIllegal; | 
 |                     break; | 
 |                 } else { | 
 |                     *target++ = UNI_REPLACEMENT_CHAR; | 
 |                 } | 
 |             } else { | 
 |                 *target++ = ch; | 
 |             } | 
 |         } else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */ | 
 |             result = sourceIllegal; | 
 |             *target++ = UNI_REPLACEMENT_CHAR; | 
 |         } | 
 |     } | 
 |     *sourceStart = source; | 
 |     *targetStart = target; | 
 |     return result; | 
 | } | 
 |  | 
 | ConversionResult ConvertUTF8toUTF32Partial(const UTF8 **sourceStart, | 
 |                                            const UTF8 *sourceEnd, | 
 |                                            UTF32 **targetStart, | 
 |                                            UTF32 *targetEnd, | 
 |                                            ConversionFlags flags) { | 
 |   return ConvertUTF8toUTF32Impl(sourceStart, sourceEnd, targetStart, targetEnd, | 
 |                                 flags, /*InputIsPartial=*/true); | 
 | } | 
 |  | 
 | ConversionResult ConvertUTF8toUTF32(const UTF8 **sourceStart, | 
 |                                     const UTF8 *sourceEnd, UTF32 **targetStart, | 
 |                                     UTF32 *targetEnd, ConversionFlags flags) { | 
 |   return ConvertUTF8toUTF32Impl(sourceStart, sourceEnd, targetStart, targetEnd, | 
 |                                 flags, /*InputIsPartial=*/false); | 
 | } | 
 |  | 
 | /* --------------------------------------------------------------------- | 
 |  | 
 |     Note A. | 
 |     The fall-through switches in UTF-8 reading code save a | 
 |     temp variable, some decrements & conditionals.  The switches | 
 |     are equivalent to the following loop: | 
 |         { | 
 |             int tmpBytesToRead = extraBytesToRead+1; | 
 |             do { | 
 |                 ch += *source++; | 
 |                 --tmpBytesToRead; | 
 |                 if (tmpBytesToRead) ch <<= 6; | 
 |             } while (tmpBytesToRead > 0); | 
 |         } | 
 |     In UTF-8 writing code, the switches on "bytesToWrite" are | 
 |     similarly unrolled loops. | 
 |  | 
 |    --------------------------------------------------------------------- */ | 
 |  | 
 | } // namespace llvm | 
 |  | 
 | ConvertUTF_RESTORE_WARNINGS |