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; /* fall-thru */ |
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271 | case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; /* fall-thru */ |
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272 | case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; /* fall-thru */ |
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273 | case 1: *--target = (UTF8)(ch | firstByteMark[bytesToWrite]); /* fall-thru */ |
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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; /* fall-thru */ |
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302 | case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; /* fall-thru */ |
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303 | case 2: if ((a = (*--srcptr)) > 0xBF) return false; /* fall-thru */ |
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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; break; |
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312 | } |
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313 | /* FALLTHRU */ |
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314 | case 1: if (*source >= 0x80 && *source < 0xC2) return false; /* fall-thru */ |
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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 */ /* fall-thru */ |
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358 | case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */ /* fall-thru */ |
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359 | case 3: ch += *source++; ch <<= 6; /* fall-thru */ |
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360 | case 2: ch += *source++; ch <<= 6; /* fall-thru */ |
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361 | case 1: ch += *source++; ch <<= 6; /* fall-thru */ |
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362 | case 0: ch += *source++; /* fall-thru */ |
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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 | /* fall-thru */ |
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450 | case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; /* fall-thru */ |
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451 | case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6; /* fall-thru */ |
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452 | case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]); /* fall-thru */ |
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453 | } |
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454 | target += bytesToWrite; |
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455 | } |
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456 | *sourceStart = source; |
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457 | *targetStart = target; |
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458 | return result; |
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459 | } |
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460 | |
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461 | /* --------------------------------------------------------------------- */ |
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462 | |
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463 | ConversionResult ConvertUTF8toUTF32 ( |
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464 | const UTF8** sourceStart, const UTF8* sourceEnd, |
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465 | UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) { |
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466 | ConversionResult result = conversionOK; |
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467 | const UTF8* source = *sourceStart; |
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468 | UTF32* target = *targetStart; |
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469 | while (source < sourceEnd) { |
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470 | UTF32 ch = 0; |
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471 | unsigned short extraBytesToRead = trailingBytesForUTF8[*source]; |
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472 | if (source + extraBytesToRead >= sourceEnd) { |
---|
473 | result = sourceExhausted; break; |
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474 | } |
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475 | /* Do this check whether lenient or strict */ |
---|
476 | if (! isLegalUTF8(source, extraBytesToRead+1)) { |
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477 | result = sourceIllegal; |
---|
478 | break; |
---|
479 | } |
---|
480 | /* |
---|
481 | * The cases all fall through. See "Note A" below. |
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482 | */ |
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483 | switch (extraBytesToRead) { |
---|
484 | case 5: ch += *source++; ch <<= 6; /* fall-thru */ |
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485 | case 4: ch += *source++; ch <<= 6; /* fall-thru */ |
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486 | case 3: ch += *source++; ch <<= 6; /* fall-thru */ |
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487 | case 2: ch += *source++; ch <<= 6; /* fall-thru */ |
---|
488 | case 1: ch += *source++; ch <<= 6; /* fall-thru */ |
---|
489 | case 0: ch += *source++; /* fall-thru */ |
---|
490 | } |
---|
491 | ch -= offsetsFromUTF8[extraBytesToRead]; |
---|
492 | |
---|
493 | if (target >= targetEnd) { |
---|
494 | source -= (extraBytesToRead+1); /* Back up the source pointer! */ |
---|
495 | result = targetExhausted; break; |
---|
496 | } |
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497 | if (ch <= UNI_MAX_LEGAL_UTF32) { |
---|
498 | /* |
---|
499 | * UTF-16 surrogate values are illegal in UTF-32, and anything |
---|
500 | * over Plane 17 (> 0x10FFFF) is illegal. |
---|
501 | */ |
---|
502 | if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) { |
---|
503 | if (flags == strictConversion) { |
---|
504 | source -= (extraBytesToRead+1); /* return to the illegal value itself */ |
---|
505 | result = sourceIllegal; |
---|
506 | break; |
---|
507 | } else { |
---|
508 | *target++ = UNI_REPLACEMENT_CHAR; |
---|
509 | } |
---|
510 | } else { |
---|
511 | *target++ = ch; |
---|
512 | } |
---|
513 | } else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */ |
---|
514 | result = sourceIllegal; |
---|
515 | *target++ = UNI_REPLACEMENT_CHAR; |
---|
516 | } |
---|
517 | } |
---|
518 | *sourceStart = source; |
---|
519 | *targetStart = target; |
---|
520 | return result; |
---|
521 | } |
---|
522 | |
---|
523 | /* --------------------------------------------------------------------- |
---|
524 | |
---|
525 | Note A. |
---|
526 | The fall-through switches in UTF-8 reading code save a |
---|
527 | temp variable, some decrements & conditionals. The switches |
---|
528 | are equivalent to the following loop: |
---|
529 | { |
---|
530 | int tmpBytesToRead = extraBytesToRead+1; |
---|
531 | do { |
---|
532 | ch += *source++; |
---|
533 | --tmpBytesToRead; |
---|
534 | if (tmpBytesToRead) ch <<= 6; |
---|
535 | } while (tmpBytesToRead > 0); |
---|
536 | } |
---|
537 | In UTF-8 writing code, the switches on "bytesToWrite" are |
---|
538 | similarly unrolled loops. |
---|
539 | |
---|
540 | --------------------------------------------------------------------- */ |
---|