[ea29902] | 1 | /* |
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| 2 | * Copyright 2001-2004 Unicode, Inc. |
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| 3 | * |
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| 4 | * Disclaimer |
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| 5 | * |
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| 6 | * This source code is provided as is by Unicode, Inc. No claims are |
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| 7 | * made as to fitness for any particular purpose. No warranties of any |
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| 8 | * kind are expressed or implied. The recipient agrees to determine |
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| 9 | * applicability of information provided. If this file has been |
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| 10 | * purchased on magnetic or optical media from Unicode, Inc., the |
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| 11 | * sole remedy for any claim will be exchange of defective media |
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| 12 | * within 90 days of receipt. |
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| 13 | * |
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| 14 | * Limitations on Rights to Redistribute This Code |
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| 15 | * |
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| 16 | * Unicode, Inc. hereby grants the right to freely use the information |
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| 17 | * supplied in this file in the creation of products supporting the |
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| 18 | * Unicode Standard, and to make copies of this file in any form |
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| 19 | * for internal or external distribution as long as this notice |
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| 20 | * remains attached. |
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| 21 | */ |
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| 22 | |
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| 23 | /* --------------------------------------------------------------------- |
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| 24 | |
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| 25 | Conversions between UTF32, UTF-16, and UTF-8. Source code file. |
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| 26 | Author: Mark E. Davis, 1994. |
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| 27 | Rev History: Rick McGowan, fixes & updates May 2001. |
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| 28 | Sept 2001: fixed const & error conditions per |
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| 29 | mods suggested by S. Parent & A. Lillich. |
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| 30 | June 2002: Tim Dodd added detection and handling of incomplete |
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| 31 | source sequences, enhanced error detection, added casts |
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| 32 | to eliminate compiler warnings. |
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| 33 | July 2003: slight mods to back out aggressive FFFE detection. |
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| 34 | Jan 2004: updated switches in from-UTF8 conversions. |
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| 35 | Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions. |
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| 36 | |
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| 37 | See the header file "ConvertUTF.h" for complete documentation. |
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| 38 | |
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| 39 | ------------------------------------------------------------------------ */ |
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| 40 | |
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| 41 | |
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| 42 | #include "ConvertUTF.h" |
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| 43 | #ifdef CVTUTF_DEBUG |
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| 44 | #include <stdio.h> |
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| 45 | #endif |
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| 46 | |
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| 47 | static const int halfShift = 10; /* used for shifting by 10 bits */ |
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| 48 | |
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| 49 | static const UTF32 halfBase = 0x0010000UL; |
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| 50 | static const UTF32 halfMask = 0x3FFUL; |
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| 51 | |
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| 52 | #define UNI_SUR_HIGH_START (UTF32)0xD800 |
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| 53 | #define UNI_SUR_HIGH_END (UTF32)0xDBFF |
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| 54 | #define UNI_SUR_LOW_START (UTF32)0xDC00 |
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| 55 | #define UNI_SUR_LOW_END (UTF32)0xDFFF |
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| 56 | #define false 0 |
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| 57 | #define true 1 |
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| 58 | |
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| 59 | /* --------------------------------------------------------------------- */ |
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| 60 | |
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| 61 | ConversionResult ConvertUTF32toUTF16 ( |
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| 62 | const UTF32** sourceStart, const UTF32* sourceEnd, |
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| 63 | UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) { |
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| 64 | ConversionResult result = conversionOK; |
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| 65 | const UTF32* source = *sourceStart; |
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| 66 | UTF16* target = *targetStart; |
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| 67 | while (source < sourceEnd) { |
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| 68 | UTF32 ch; |
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| 69 | if (target >= targetEnd) { |
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| 70 | result = targetExhausted; break; |
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| 71 | } |
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| 72 | ch = *source++; |
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| 73 | if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */ |
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| 74 | /* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */ |
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| 75 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
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| 76 | if (flags == strictConversion) { |
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| 77 | --source; /* return to the illegal value itself */ |
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| 78 | result = sourceIllegal; |
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| 79 | break; |
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| 80 | } else { |
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| 81 | *target++ = UNI_REPLACEMENT_CHAR; |
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| 82 | } |
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| 83 | } else { |
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| 84 | *target++ = (UTF16)ch; /* normal case */ |
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| 85 | } |
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| 86 | } else if (ch > UNI_MAX_LEGAL_UTF32) { |
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| 87 | if (flags == strictConversion) { |
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| 88 | result = sourceIllegal; |
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| 89 | } else { |
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| 90 | *target++ = UNI_REPLACEMENT_CHAR; |
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| 91 | } |
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| 92 | } else { |
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| 93 | /* target is a character in range 0xFFFF - 0x10FFFF. */ |
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| 94 | if (target + 1 >= targetEnd) { |
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| 95 | --source; /* Back up source pointer! */ |
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| 96 | result = targetExhausted; break; |
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| 97 | } |
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| 98 | ch -= halfBase; |
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| 99 | *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START); |
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| 100 | *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START); |
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| 101 | } |
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| 102 | } |
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| 103 | *sourceStart = source; |
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| 104 | *targetStart = target; |
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| 105 | return result; |
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| 106 | } |
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| 107 | |
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| 108 | /* --------------------------------------------------------------------- */ |
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| 109 | |
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| 110 | ConversionResult ConvertUTF16toUTF32 ( |
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| 111 | const UTF16** sourceStart, const UTF16* sourceEnd, |
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| 112 | UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) { |
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| 113 | ConversionResult result = conversionOK; |
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| 114 | const UTF16* source = *sourceStart; |
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| 115 | UTF32* target = *targetStart; |
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| 116 | UTF32 ch, ch2; |
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| 117 | while (source < sourceEnd) { |
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| 118 | const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */ |
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| 119 | ch = *source++; |
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| 120 | /* If we have a surrogate pair, convert to UTF32 first. */ |
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| 121 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) { |
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| 122 | /* If the 16 bits following the high surrogate are in the source buffer... */ |
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| 123 | if (source < sourceEnd) { |
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| 124 | ch2 = *source; |
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| 125 | /* If it's a low surrogate, convert to UTF32. */ |
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| 126 | if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) { |
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| 127 | ch = ((ch - UNI_SUR_HIGH_START) << halfShift) |
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| 128 | + (ch2 - UNI_SUR_LOW_START) + halfBase; |
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| 129 | ++source; |
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| 130 | } else if (flags == strictConversion) { /* it's an unpaired high surrogate */ |
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| 131 | --source; /* return to the illegal value itself */ |
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| 132 | result = sourceIllegal; |
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| 133 | break; |
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| 134 | } |
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| 135 | } else { /* We don't have the 16 bits following the high surrogate. */ |
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| 136 | --source; /* return to the high surrogate */ |
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| 137 | result = sourceExhausted; |
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| 138 | break; |
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| 139 | } |
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| 140 | } else if (flags == strictConversion) { |
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| 141 | /* UTF-16 surrogate values are illegal in UTF-32 */ |
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| 142 | if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) { |
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| 143 | --source; /* return to the illegal value itself */ |
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| 144 | result = sourceIllegal; |
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| 145 | break; |
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| 146 | } |
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| 147 | } |
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| 148 | if (target >= targetEnd) { |
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| 149 | source = oldSource; /* Back up source pointer! */ |
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| 150 | result = targetExhausted; break; |
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| 151 | } |
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| 152 | *target++ = ch; |
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| 153 | } |
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| 154 | *sourceStart = source; |
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| 155 | *targetStart = target; |
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| 156 | #ifdef CVTUTF_DEBUG |
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| 157 | if (result == sourceIllegal) { |
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| 158 | fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2); |
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| 159 | fflush(stderr); |
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| 160 | } |
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| 161 | #endif |
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| 162 | return result; |
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| 163 | } |
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| 164 | |
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| 165 | /* --------------------------------------------------------------------- */ |
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| 166 | |
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| 167 | /* |
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| 168 | * Index into the table below with the first byte of a UTF-8 sequence to |
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| 169 | * get the number of trailing bytes that are supposed to follow it. |
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| 170 | * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is |
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| 171 | * left as-is for anyone who may want to do such conversion, which was |
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| 172 | * allowed in earlier algorithms. |
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| 173 | */ |
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| 174 | static const char trailingBytesForUTF8[256] = { |
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| 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, |
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| 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, |
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| 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, |
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| 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, |
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| 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, |
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| 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, |
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| 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, |
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| 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 |
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| 183 | }; |
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| 184 | |
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| 185 | /* |
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| 186 | * Magic values subtracted from a buffer value during UTF8 conversion. |
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| 187 | * This table contains as many values as there might be trailing bytes |
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| 188 | * in a UTF-8 sequence. |
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| 189 | */ |
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| 190 | static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL, |
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| 191 | 0x03C82080UL, 0xFA082080UL, 0x82082080UL }; |
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| 192 | |
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| 193 | /* |
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| 194 | * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed |
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| 195 | * into the first byte, depending on how many bytes follow. There are |
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| 196 | * as many entries in this table as there are UTF-8 sequence types. |
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| 197 | * (I.e., one byte sequence, two byte... etc.). Remember that sequencs |
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| 198 | * for *legal* UTF-8 will be 4 or fewer bytes total. |
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| 199 | */ |
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| 200 | static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC }; |
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| 201 | |
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| 202 | /* --------------------------------------------------------------------- */ |
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| 203 | |
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| 204 | /* The interface converts a whole buffer to avoid function-call overhead. |
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| 205 | * Constants have been gathered. Loops & conditionals have been removed as |
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| 206 | * much as possible for efficiency, in favor of drop-through switches. |
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| 207 | * (See "Note A" at the bottom of the file for equivalent code.) |
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| 208 | * If your compiler supports it, the "isLegalUTF8" call can be turned |
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| 209 | * into an inline function. |
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| 210 | */ |
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| 211 | |
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| 212 | /* --------------------------------------------------------------------- */ |
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| 213 | |
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| 214 | ConversionResult ConvertUTF16toUTF8 ( |
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| 215 | const UTF16** sourceStart, const UTF16* sourceEnd, |
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| 216 | UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) { |
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| 217 | ConversionResult result = conversionOK; |
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| 218 | const UTF16* source = *sourceStart; |
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| 219 | UTF8* target = *targetStart; |
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| 220 | while (source < sourceEnd) { |
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| 221 | UTF32 ch; |
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| 222 | unsigned short bytesToWrite = 0; |
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| 223 | const UTF32 byteMask = 0xBF; |
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| 224 | const UTF32 byteMark = 0x80; |
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| 225 | const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */ |
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| 226 | ch = *source++; |
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| 227 | /* If we have a surrogate pair, convert to UTF32 first. */ |
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| 228 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) { |
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| 229 | /* If the 16 bits following the high surrogate are in the source buffer... */ |
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| 230 | if (source < sourceEnd) { |
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| 231 | UTF32 ch2 = *source; |
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| 232 | /* If it's a low surrogate, convert to UTF32. */ |
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| 233 | if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) { |
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| 234 | ch = ((ch - UNI_SUR_HIGH_START) << halfShift) |
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| 235 | + (ch2 - UNI_SUR_LOW_START) + halfBase; |
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| 236 | ++source; |
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| 237 | } else if (flags == strictConversion) { /* it's an unpaired high surrogate */ |
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| 238 | --source; /* return to the illegal value itself */ |
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| 239 | result = sourceIllegal; |
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| 240 | break; |
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| 241 | } |
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| 242 | } else { /* We don't have the 16 bits following the high surrogate. */ |
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| 243 | --source; /* return to the high surrogate */ |
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| 244 | result = sourceExhausted; |
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| 245 | break; |
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| 246 | } |
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| 247 | } else if (flags == strictConversion) { |
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| 248 | /* UTF-16 surrogate values are illegal in UTF-32 */ |
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| 249 | if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) { |
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| 250 | --source; /* return to the illegal value itself */ |
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| 251 | result = sourceIllegal; |
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| 252 | break; |
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| 253 | } |
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| 254 | } |
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| 255 | /* Figure out how many bytes the result will require */ |
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| 256 | if (ch < (UTF32)0x80) { bytesToWrite = 1; |
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| 257 | } else if (ch < (UTF32)0x800) { bytesToWrite = 2; |
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| 258 | } else if (ch < (UTF32)0x10000) { bytesToWrite = 3; |
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| 259 | } else if (ch < (UTF32)0x110000) { bytesToWrite = 4; |
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| 260 | } else { bytesToWrite = 3; |
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| 261 | ch = UNI_REPLACEMENT_CHAR; |
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| 262 | } |
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| 263 | |
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| 264 | target += bytesToWrite; |
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| 265 | if (target > targetEnd) { |
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| 266 | source = oldSource; /* Back up source pointer! */ |
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| 267 | target -= bytesToWrite; result = targetExhausted; break; |
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| 268 | } |
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| 269 | switch (bytesToWrite) { /* note: everything falls through. */ |
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| 270 | case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
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| 271 | case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
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| 272 | case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
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| 273 | case 1: *--target = (UTF8)(ch | firstByteMark[bytesToWrite]); |
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| 274 | } |
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| 275 | target += bytesToWrite; |
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| 276 | } |
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| 277 | *sourceStart = source; |
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| 278 | *targetStart = target; |
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| 279 | return result; |
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| 280 | } |
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| 281 | |
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| 282 | /* --------------------------------------------------------------------- */ |
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| 283 | |
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| 284 | /* |
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| 285 | * Utility routine to tell whether a sequence of bytes is legal UTF-8. |
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| 286 | * This must be called with the length pre-determined by the first byte. |
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| 287 | * If not calling this from ConvertUTF8to*, then the length can be set by: |
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| 288 | * length = trailingBytesForUTF8[*source]+1; |
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| 289 | * and the sequence is illegal right away if there aren't that many bytes |
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| 290 | * available. |
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| 291 | * If presented with a length > 4, this returns false. The Unicode |
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| 292 | * definition of UTF-8 goes up to 4-byte sequences. |
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| 293 | */ |
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| 294 | |
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| 295 | static Boolean isLegalUTF8(const UTF8 *source, int length) { |
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| 296 | UTF8 a; |
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| 297 | const UTF8 *srcptr = source+length; |
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| 298 | switch (length) { |
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| 299 | default: return false; |
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| 300 | /* Everything else falls through when "true"... */ |
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| 301 | case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; |
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| 302 | case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; |
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| 303 | case 2: if ((a = (*--srcptr)) > 0xBF) return false; |
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| 304 | |
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| 305 | switch (*source) { |
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| 306 | /* no fall-through in this inner switch */ |
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| 307 | case 0xE0: if (a < 0xA0) return false; break; |
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| 308 | case 0xED: if (a > 0x9F) return false; break; |
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| 309 | case 0xF0: if (a < 0x90) return false; break; |
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| 310 | case 0xF4: if (a > 0x8F) return false; break; |
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| 311 | default: if (a < 0x80) return false; |
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| 312 | } |
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| 313 | |
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| 314 | case 1: if (*source >= 0x80 && *source < 0xC2) return false; |
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| 315 | } |
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| 316 | if (*source > 0xF4) return false; |
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| 317 | return true; |
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| 318 | } |
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| 319 | |
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| 320 | /* --------------------------------------------------------------------- */ |
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| 321 | |
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| 322 | /* |
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| 323 | * Exported function to return whether a UTF-8 sequence is legal or not. |
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| 324 | * This is not used here; it's just exported. |
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| 325 | */ |
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| 326 | Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) { |
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| 327 | int length = trailingBytesForUTF8[*source]+1; |
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| 328 | if (source+length > sourceEnd) { |
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| 329 | return false; |
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| 330 | } |
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| 331 | return isLegalUTF8(source, length); |
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| 332 | } |
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| 333 | |
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| 334 | /* --------------------------------------------------------------------- */ |
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| 335 | |
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| 336 | ConversionResult ConvertUTF8toUTF16 ( |
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| 337 | const UTF8** sourceStart, const UTF8* sourceEnd, |
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| 338 | UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) { |
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| 339 | ConversionResult result = conversionOK; |
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| 340 | const UTF8* source = *sourceStart; |
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| 341 | UTF16* target = *targetStart; |
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| 342 | while (source < sourceEnd) { |
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| 343 | UTF32 ch = 0; |
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| 344 | unsigned short extraBytesToRead = trailingBytesForUTF8[*source]; |
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| 345 | if (source + extraBytesToRead >= sourceEnd) { |
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| 346 | result = sourceExhausted; break; |
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| 347 | } |
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| 348 | /* Do this check whether lenient or strict */ |
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| 349 | if (! isLegalUTF8(source, extraBytesToRead+1)) { |
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| 350 | result = sourceIllegal; |
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| 351 | break; |
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| 352 | } |
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| 353 | /* |
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| 354 | * The cases all fall through. See "Note A" below. |
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| 355 | */ |
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| 356 | switch (extraBytesToRead) { |
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| 357 | case 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */ |
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| 358 | case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */ |
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| 359 | case 3: ch += *source++; ch <<= 6; |
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| 360 | case 2: ch += *source++; ch <<= 6; |
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| 361 | case 1: ch += *source++; ch <<= 6; |
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| 362 | case 0: ch += *source++; |
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| 363 | } |
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| 364 | ch -= offsetsFromUTF8[extraBytesToRead]; |
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| 365 | |
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| 366 | if (target >= targetEnd) { |
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| 367 | source -= (extraBytesToRead+1); /* Back up source pointer! */ |
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| 368 | result = targetExhausted; break; |
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| 369 | } |
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| 370 | if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */ |
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| 371 | /* UTF-16 surrogate values are illegal in UTF-32 */ |
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| 372 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
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| 373 | if (flags == strictConversion) { |
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| 374 | source -= (extraBytesToRead+1); /* return to the illegal value itself */ |
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| 375 | result = sourceIllegal; |
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| 376 | break; |
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| 377 | } else { |
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| 378 | *target++ = UNI_REPLACEMENT_CHAR; |
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| 379 | } |
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| 380 | } else { |
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| 381 | *target++ = (UTF16)ch; /* normal case */ |
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| 382 | } |
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| 383 | } else if (ch > UNI_MAX_UTF16) { |
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| 384 | if (flags == strictConversion) { |
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| 385 | result = sourceIllegal; |
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| 386 | source -= (extraBytesToRead+1); /* return to the start */ |
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| 387 | break; /* Bail out; shouldn't continue */ |
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| 388 | } else { |
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| 389 | *target++ = UNI_REPLACEMENT_CHAR; |
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| 390 | } |
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| 391 | } else { |
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| 392 | /* target is a character in range 0xFFFF - 0x10FFFF. */ |
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| 393 | if (target + 1 >= targetEnd) { |
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| 394 | source -= (extraBytesToRead+1); /* Back up source pointer! */ |
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| 395 | result = targetExhausted; break; |
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| 396 | } |
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| 397 | ch -= halfBase; |
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| 398 | *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START); |
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| 399 | *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START); |
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| 400 | } |
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| 401 | } |
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| 402 | *sourceStart = source; |
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| 403 | *targetStart = target; |
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| 404 | return result; |
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| 405 | } |
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| 406 | |
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| 407 | /* --------------------------------------------------------------------- */ |
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| 408 | |
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| 409 | ConversionResult ConvertUTF32toUTF8 ( |
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| 410 | const UTF32** sourceStart, const UTF32* sourceEnd, |
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| 411 | UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) { |
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| 412 | ConversionResult result = conversionOK; |
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| 413 | const UTF32* source = *sourceStart; |
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| 414 | UTF8* target = *targetStart; |
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| 415 | while (source < sourceEnd) { |
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| 416 | UTF32 ch; |
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| 417 | unsigned short bytesToWrite = 0; |
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| 418 | const UTF32 byteMask = 0xBF; |
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| 419 | const UTF32 byteMark = 0x80; |
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| 420 | ch = *source++; |
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| 421 | if (flags == strictConversion ) { |
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| 422 | /* UTF-16 surrogate values are illegal in UTF-32 */ |
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| 423 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
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| 424 | --source; /* return to the illegal value itself */ |
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| 425 | result = sourceIllegal; |
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| 426 | break; |
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| 427 | } |
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| 428 | } |
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| 429 | /* |
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| 430 | * Figure out how many bytes the result will require. Turn any |
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| 431 | * illegally large UTF32 things (> Plane 17) into replacement chars. |
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| 432 | */ |
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| 433 | if (ch < (UTF32)0x80) { bytesToWrite = 1; |
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| 434 | } else if (ch < (UTF32)0x800) { bytesToWrite = 2; |
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| 435 | } else if (ch < (UTF32)0x10000) { bytesToWrite = 3; |
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| 436 | } else if (ch <= UNI_MAX_LEGAL_UTF32) { bytesToWrite = 4; |
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| 437 | } else { bytesToWrite = 3; |
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| 438 | ch = UNI_REPLACEMENT_CHAR; |
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| 439 | result = sourceIllegal; |
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| 440 | } |
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| 441 | |
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| 442 | target += bytesToWrite; |
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| 443 | if (target > targetEnd) { |
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| 444 | --source; /* Back up source pointer! */ |
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| 445 | target -= bytesToWrite; result = targetExhausted; break; |
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| 446 | } |
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| 447 | switch (bytesToWrite) { /* note: everything falls through. */ |
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| 448 | case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
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| 449 | case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
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| 450 | case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; |
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| 451 | case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]); |
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| 452 | } |
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| 453 | target += bytesToWrite; |
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| 454 | } |
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| 455 | *sourceStart = source; |
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| 456 | *targetStart = target; |
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| 457 | return result; |
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| 458 | } |
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| 459 | |
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| 460 | /* --------------------------------------------------------------------- */ |
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| 461 | |
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| 462 | ConversionResult ConvertUTF8toUTF32 ( |
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| 463 | const UTF8** sourceStart, const UTF8* sourceEnd, |
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| 464 | UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) { |
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| 465 | ConversionResult result = conversionOK; |
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| 466 | const UTF8* source = *sourceStart; |
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| 467 | UTF32* target = *targetStart; |
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| 468 | while (source < sourceEnd) { |
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| 469 | UTF32 ch = 0; |
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| 470 | unsigned short extraBytesToRead = trailingBytesForUTF8[*source]; |
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| 471 | if (source + extraBytesToRead >= sourceEnd) { |
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| 472 | result = sourceExhausted; break; |
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| 473 | } |
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| 474 | /* Do this check whether lenient or strict */ |
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| 475 | if (! isLegalUTF8(source, extraBytesToRead+1)) { |
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| 476 | result = sourceIllegal; |
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| 477 | break; |
---|
| 478 | } |
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| 479 | /* |
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| 480 | * The cases all fall through. See "Note A" below. |
---|
| 481 | */ |
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| 482 | switch (extraBytesToRead) { |
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| 483 | case 5: ch += *source++; ch <<= 6; |
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| 484 | case 4: ch += *source++; ch <<= 6; |
---|
| 485 | case 3: ch += *source++; ch <<= 6; |
---|
| 486 | case 2: ch += *source++; ch <<= 6; |
---|
| 487 | case 1: ch += *source++; ch <<= 6; |
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| 488 | case 0: ch += *source++; |
---|
| 489 | } |
---|
| 490 | ch -= offsetsFromUTF8[extraBytesToRead]; |
---|
| 491 | |
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| 492 | if (target >= targetEnd) { |
---|
| 493 | source -= (extraBytesToRead+1); /* Back up the source pointer! */ |
---|
| 494 | result = targetExhausted; break; |
---|
| 495 | } |
---|
| 496 | if (ch <= UNI_MAX_LEGAL_UTF32) { |
---|
| 497 | /* |
---|
| 498 | * UTF-16 surrogate values are illegal in UTF-32, and anything |
---|
| 499 | * over Plane 17 (> 0x10FFFF) is illegal. |
---|
| 500 | */ |
---|
| 501 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
---|
| 502 | if (flags == strictConversion) { |
---|
| 503 | source -= (extraBytesToRead+1); /* return to the illegal value itself */ |
---|
| 504 | result = sourceIllegal; |
---|
| 505 | break; |
---|
| 506 | } else { |
---|
| 507 | *target++ = UNI_REPLACEMENT_CHAR; |
---|
| 508 | } |
---|
| 509 | } else { |
---|
| 510 | *target++ = ch; |
---|
| 511 | } |
---|
| 512 | } else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */ |
---|
| 513 | result = sourceIllegal; |
---|
| 514 | *target++ = UNI_REPLACEMENT_CHAR; |
---|
| 515 | } |
---|
| 516 | } |
---|
| 517 | *sourceStart = source; |
---|
| 518 | *targetStart = target; |
---|
| 519 | return result; |
---|
| 520 | } |
---|
| 521 | |
---|
| 522 | /* --------------------------------------------------------------------- |
---|
| 523 | |
---|
| 524 | Note A. |
---|
| 525 | The fall-through switches in UTF-8 reading code save a |
---|
| 526 | temp variable, some decrements & conditionals. The switches |
---|
| 527 | are equivalent to the following loop: |
---|
| 528 | { |
---|
| 529 | int tmpBytesToRead = extraBytesToRead+1; |
---|
| 530 | do { |
---|
| 531 | ch += *source++; |
---|
| 532 | --tmpBytesToRead; |
---|
| 533 | if (tmpBytesToRead) ch <<= 6; |
---|
| 534 | } while (tmpBytesToRead > 0); |
---|
| 535 | } |
---|
| 536 | In UTF-8 writing code, the switches on "bytesToWrite" are |
---|
| 537 | similarly unrolled loops. |
---|
| 538 | |
---|
| 539 | --------------------------------------------------------------------- */ |
---|