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1 |
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2 #include "yaml_private.h" |
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3 |
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4 /* |
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5 * Declarations. |
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6 */ |
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7 |
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8 static int |
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9 yaml_parser_set_reader_error(yaml_parser_t *parser, const char *problem, |
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10 size_t offset, int value); |
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11 |
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12 static int |
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13 yaml_parser_update_raw_buffer(yaml_parser_t *parser); |
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14 |
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15 static int |
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16 yaml_parser_determine_encoding(yaml_parser_t *parser); |
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17 |
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18 YAML_DECLARE(int) |
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19 yaml_parser_update_buffer(yaml_parser_t *parser, size_t length); |
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20 |
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21 /* |
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22 * Set the reader error and return 0. |
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23 */ |
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24 |
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25 static int |
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26 yaml_parser_set_reader_error(yaml_parser_t *parser, const char *problem, |
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27 size_t offset, int value) |
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28 { |
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29 parser->error = YAML_READER_ERROR; |
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30 parser->problem = problem; |
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31 parser->problem_offset = offset; |
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32 parser->problem_value = value; |
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33 |
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34 return 0; |
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35 } |
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36 |
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37 /* |
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38 * Byte order marks. |
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39 */ |
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40 |
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41 #define BOM_UTF8 "\xef\xbb\xbf" |
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42 #define BOM_UTF16LE "\xff\xfe" |
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43 #define BOM_UTF16BE "\xfe\xff" |
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44 |
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45 /* |
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46 * Determine the input stream encoding by checking the BOM symbol. If no BOM is |
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47 * found, the UTF-8 encoding is assumed. Return 1 on success, 0 on failure. |
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48 */ |
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49 |
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50 static int |
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51 yaml_parser_determine_encoding(yaml_parser_t *parser) |
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52 { |
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53 /* Ensure that we had enough bytes in the raw buffer. */ |
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54 |
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55 while (!parser->eof |
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56 && parser->raw_buffer.last - parser->raw_buffer.pointer < 3) { |
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57 if (!yaml_parser_update_raw_buffer(parser)) { |
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58 return 0; |
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59 } |
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60 } |
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61 |
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62 /* Determine the encoding. */ |
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63 |
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64 if (parser->raw_buffer.last - parser->raw_buffer.pointer >= 2 |
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65 && !memcmp(parser->raw_buffer.pointer, BOM_UTF16LE, 2)) { |
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66 parser->encoding = YAML_UTF16LE_ENCODING; |
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67 parser->raw_buffer.pointer += 2; |
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68 parser->offset += 2; |
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69 } |
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70 else if (parser->raw_buffer.last - parser->raw_buffer.pointer >= 2 |
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71 && !memcmp(parser->raw_buffer.pointer, BOM_UTF16BE, 2)) { |
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72 parser->encoding = YAML_UTF16BE_ENCODING; |
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73 parser->raw_buffer.pointer += 2; |
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74 parser->offset += 2; |
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75 } |
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76 else if (parser->raw_buffer.last - parser->raw_buffer.pointer >= 3 |
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77 && !memcmp(parser->raw_buffer.pointer, BOM_UTF8, 3)) { |
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78 parser->encoding = YAML_UTF8_ENCODING; |
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79 parser->raw_buffer.pointer += 3; |
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80 parser->offset += 3; |
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81 } |
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82 else { |
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83 parser->encoding = YAML_UTF8_ENCODING; |
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84 } |
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85 |
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86 return 1; |
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87 } |
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88 |
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89 /* |
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90 * Update the raw buffer. |
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91 */ |
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92 |
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93 static int |
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94 yaml_parser_update_raw_buffer(yaml_parser_t *parser) |
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95 { |
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96 size_t size_read = 0; |
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97 |
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98 /* Return if the raw buffer is full. */ |
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99 |
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100 if (parser->raw_buffer.start == parser->raw_buffer.pointer |
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101 && parser->raw_buffer.last == parser->raw_buffer.end) |
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102 return 1; |
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103 |
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104 /* Return on EOF. */ |
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105 |
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106 if (parser->eof) return 1; |
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107 |
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108 /* Move the remaining bytes in the raw buffer to the beginning. */ |
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109 |
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110 if (parser->raw_buffer.start < parser->raw_buffer.pointer |
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111 && parser->raw_buffer.pointer < parser->raw_buffer.last) { |
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112 memmove(parser->raw_buffer.start, parser->raw_buffer.pointer, |
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113 parser->raw_buffer.last - parser->raw_buffer.pointer); |
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114 } |
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115 parser->raw_buffer.last -= |
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116 parser->raw_buffer.pointer - parser->raw_buffer.start; |
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117 parser->raw_buffer.pointer = parser->raw_buffer.start; |
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118 |
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119 /* Call the read handler to fill the buffer. */ |
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120 |
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121 if (!parser->read_handler(parser->read_handler_data, parser->raw_buffer.last, |
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122 parser->raw_buffer.end - parser->raw_buffer.last, &size_read)) { |
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123 return yaml_parser_set_reader_error(parser, "input error", |
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124 parser->offset, -1); |
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125 } |
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126 parser->raw_buffer.last += size_read; |
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127 if (!size_read) { |
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128 parser->eof = 1; |
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129 } |
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130 |
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131 return 1; |
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132 } |
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133 |
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134 /* |
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135 * Ensure that the buffer contains at least `length` characters. |
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136 * Return 1 on success, 0 on failure. |
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137 * |
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138 * The length is supposed to be significantly less that the buffer size. |
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139 */ |
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140 |
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141 YAML_DECLARE(int) |
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142 yaml_parser_update_buffer(yaml_parser_t *parser, size_t length) |
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143 { |
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144 int first = 1; |
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145 |
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146 assert(parser->read_handler); /* Read handler must be set. */ |
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147 |
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148 /* If the EOF flag is set and the raw buffer is empty, do nothing. */ |
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149 |
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150 if (parser->eof && parser->raw_buffer.pointer == parser->raw_buffer.last) |
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151 return 1; |
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152 |
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153 /* Return if the buffer contains enough characters. */ |
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154 |
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155 if (parser->unread >= length) |
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156 return 1; |
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157 |
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158 /* Determine the input encoding if it is not known yet. */ |
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159 |
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160 if (!parser->encoding) { |
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161 if (!yaml_parser_determine_encoding(parser)) |
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162 return 0; |
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163 } |
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164 |
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165 /* Move the unread characters to the beginning of the buffer. */ |
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166 |
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167 if (parser->buffer.start < parser->buffer.pointer |
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168 && parser->buffer.pointer < parser->buffer.last) { |
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169 size_t size = parser->buffer.last - parser->buffer.pointer; |
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170 memmove(parser->buffer.start, parser->buffer.pointer, size); |
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171 parser->buffer.pointer = parser->buffer.start; |
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172 parser->buffer.last = parser->buffer.start + size; |
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173 } |
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174 else if (parser->buffer.pointer == parser->buffer.last) { |
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175 parser->buffer.pointer = parser->buffer.start; |
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176 parser->buffer.last = parser->buffer.start; |
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177 } |
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178 |
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179 /* Fill the buffer until it has enough characters. */ |
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180 |
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181 while (parser->unread < length) |
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182 { |
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183 /* Fill the raw buffer if necessary. */ |
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184 |
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185 if (!first || parser->raw_buffer.pointer == parser->raw_buffer.last) { |
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186 if (!yaml_parser_update_raw_buffer(parser)) return 0; |
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187 } |
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188 first = 0; |
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189 |
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190 /* Decode the raw buffer. */ |
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191 |
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192 while (parser->raw_buffer.pointer != parser->raw_buffer.last) |
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193 { |
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194 unsigned int value = 0, value2 = 0; |
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195 int incomplete = 0; |
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196 unsigned char octet; |
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197 unsigned int width = 0; |
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198 int low, high; |
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199 size_t k; |
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200 size_t raw_unread = parser->raw_buffer.last - parser->raw_buffer.pointer; |
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201 |
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202 /* Decode the next character. */ |
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203 |
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204 switch (parser->encoding) |
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205 { |
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206 case YAML_UTF8_ENCODING: |
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207 |
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208 /* |
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209 * Decode a UTF-8 character. Check RFC 3629 |
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210 * (http://www.ietf.org/rfc/rfc3629.txt) for more details. |
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211 * |
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212 * The following table (taken from the RFC) is used for |
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213 * decoding. |
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214 * |
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215 * Char. number range | UTF-8 octet sequence |
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216 * (hexadecimal) | (binary) |
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217 * --------------------+------------------------------------ |
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218 * 0000 0000-0000 007F | 0xxxxxxx |
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219 * 0000 0080-0000 07FF | 110xxxxx 10xxxxxx |
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220 * 0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx |
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221 * 0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx |
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222 * |
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223 * Additionally, the characters in the range 0xD800-0xDFFF |
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224 * are prohibited as they are reserved for use with UTF-16 |
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225 * surrogate pairs. |
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226 */ |
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227 |
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228 /* Determine the length of the UTF-8 sequence. */ |
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229 |
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230 octet = parser->raw_buffer.pointer[0]; |
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231 width = (octet & 0x80) == 0x00 ? 1 : |
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232 (octet & 0xE0) == 0xC0 ? 2 : |
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233 (octet & 0xF0) == 0xE0 ? 3 : |
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234 (octet & 0xF8) == 0xF0 ? 4 : 0; |
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235 |
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236 /* Check if the leading octet is valid. */ |
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237 |
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238 if (!width) |
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239 return yaml_parser_set_reader_error(parser, |
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240 "invalid leading UTF-8 octet", |
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241 parser->offset, octet); |
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242 |
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243 /* Check if the raw buffer contains an incomplete character. */ |
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244 |
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245 if (width > raw_unread) { |
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246 if (parser->eof) { |
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247 return yaml_parser_set_reader_error(parser, |
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248 "incomplete UTF-8 octet sequence", |
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249 parser->offset, -1); |
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250 } |
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251 incomplete = 1; |
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252 break; |
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253 } |
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254 |
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255 /* Decode the leading octet. */ |
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256 |
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257 value = (octet & 0x80) == 0x00 ? octet & 0x7F : |
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258 (octet & 0xE0) == 0xC0 ? octet & 0x1F : |
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259 (octet & 0xF0) == 0xE0 ? octet & 0x0F : |
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260 (octet & 0xF8) == 0xF0 ? octet & 0x07 : 0; |
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261 |
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262 /* Check and decode the trailing octets. */ |
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263 |
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264 for (k = 1; k < width; k ++) |
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265 { |
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266 octet = parser->raw_buffer.pointer[k]; |
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267 |
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268 /* Check if the octet is valid. */ |
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269 |
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270 if ((octet & 0xC0) != 0x80) |
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271 return yaml_parser_set_reader_error(parser, |
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272 "invalid trailing UTF-8 octet", |
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273 parser->offset+k, octet); |
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274 |
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275 /* Decode the octet. */ |
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276 |
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277 value = (value << 6) + (octet & 0x3F); |
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278 } |
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279 |
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280 /* Check the length of the sequence against the value. */ |
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281 |
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282 if (!((width == 1) || |
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283 (width == 2 && value >= 0x80) || |
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284 (width == 3 && value >= 0x800) || |
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285 (width == 4 && value >= 0x10000))) |
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286 return yaml_parser_set_reader_error(parser, |
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287 "invalid length of a UTF-8 sequence", |
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288 parser->offset, -1); |
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289 |
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290 /* Check the range of the value. */ |
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291 |
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292 if ((value >= 0xD800 && value <= 0xDFFF) || value > 0x10FFFF) |
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293 return yaml_parser_set_reader_error(parser, |
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294 "invalid Unicode character", |
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295 parser->offset, value); |
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296 |
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297 break; |
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298 |
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299 case YAML_UTF16LE_ENCODING: |
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300 case YAML_UTF16BE_ENCODING: |
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301 |
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302 low = (parser->encoding == YAML_UTF16LE_ENCODING ? 0 : 1); |
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303 high = (parser->encoding == YAML_UTF16LE_ENCODING ? 1 : 0); |
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304 |
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305 /* |
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306 * The UTF-16 encoding is not as simple as one might |
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307 * naively think. Check RFC 2781 |
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308 * (http://www.ietf.org/rfc/rfc2781.txt). |
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309 * |
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310 * Normally, two subsequent bytes describe a Unicode |
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311 * character. However a special technique (called a |
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312 * surrogate pair) is used for specifying character |
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313 * values larger than 0xFFFF. |
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314 * |
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315 * A surrogate pair consists of two pseudo-characters: |
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316 * high surrogate area (0xD800-0xDBFF) |
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317 * low surrogate area (0xDC00-0xDFFF) |
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318 * |
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319 * The following formulas are used for decoding |
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320 * and encoding characters using surrogate pairs: |
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321 * |
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322 * U = U' + 0x10000 (0x01 00 00 <= U <= 0x10 FF FF) |
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323 * U' = yyyyyyyyyyxxxxxxxxxx (0 <= U' <= 0x0F FF FF) |
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324 * W1 = 110110yyyyyyyyyy |
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325 * W2 = 110111xxxxxxxxxx |
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326 * |
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327 * where U is the character value, W1 is the high surrogate |
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328 * area, W2 is the low surrogate area. |
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329 */ |
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330 |
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331 /* Check for incomplete UTF-16 character. */ |
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332 |
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333 if (raw_unread < 2) { |
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334 if (parser->eof) { |
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335 return yaml_parser_set_reader_error(parser, |
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336 "incomplete UTF-16 character", |
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337 parser->offset, -1); |
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338 } |
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339 incomplete = 1; |
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340 break; |
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341 } |
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342 |
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343 /* Get the character. */ |
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344 |
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345 value = parser->raw_buffer.pointer[low] |
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346 + (parser->raw_buffer.pointer[high] << 8); |
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347 |
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348 /* Check for unexpected low surrogate area. */ |
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349 |
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350 if ((value & 0xFC00) == 0xDC00) |
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351 return yaml_parser_set_reader_error(parser, |
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352 "unexpected low surrogate area", |
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353 parser->offset, value); |
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354 |
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355 /* Check for a high surrogate area. */ |
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356 |
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357 if ((value & 0xFC00) == 0xD800) { |
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358 |
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359 width = 4; |
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360 |
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361 /* Check for incomplete surrogate pair. */ |
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362 |
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363 if (raw_unread < 4) { |
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364 if (parser->eof) { |
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365 return yaml_parser_set_reader_error(parser, |
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366 "incomplete UTF-16 surrogate pair", |
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367 parser->offset, -1); |
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368 } |
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369 incomplete = 1; |
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370 break; |
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371 } |
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372 |
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373 /* Get the next character. */ |
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374 |
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375 value2 = parser->raw_buffer.pointer[low+2] |
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376 + (parser->raw_buffer.pointer[high+2] << 8); |
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377 |
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378 /* Check for a low surrogate area. */ |
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379 |
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380 if ((value2 & 0xFC00) != 0xDC00) |
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381 return yaml_parser_set_reader_error(parser, |
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382 "expected low surrogate area", |
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383 parser->offset+2, value2); |
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384 |
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385 /* Generate the value of the surrogate pair. */ |
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386 |
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387 value = 0x10000 + ((value & 0x3FF) << 10) + (value2 & 0x3FF); |
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388 } |
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389 |
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390 else { |
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391 width = 2; |
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392 } |
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393 |
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394 break; |
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395 |
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396 default: |
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397 assert(1); /* Impossible. */ |
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398 } |
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399 |
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400 /* Check if the raw buffer contains enough bytes to form a character. */ |
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401 |
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402 if (incomplete) break; |
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403 |
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404 /* |
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405 * Check if the character is in the allowed range: |
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406 * #x9 | #xA | #xD | [#x20-#x7E] (8 bit) |
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407 * | #x85 | [#xA0-#xD7FF] | [#xE000-#xFFFD] (16 bit) |
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408 * | [#x10000-#x10FFFF] (32 bit) |
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409 */ |
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410 |
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411 if (! (value == 0x09 || value == 0x0A || value == 0x0D |
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412 || (value >= 0x20 && value <= 0x7E) |
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413 || (value == 0x85) || (value >= 0xA0 && value <= 0xD7FF) |
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414 || (value >= 0xE000 && value <= 0xFFFD) |
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415 || (value >= 0x10000 && value <= 0x10FFFF))) |
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416 return yaml_parser_set_reader_error(parser, |
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417 "control characters are not allowed", |
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418 parser->offset, value); |
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419 |
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420 /* Move the raw pointers. */ |
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421 |
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422 parser->raw_buffer.pointer += width; |
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423 parser->offset += width; |
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424 |
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425 /* Finally put the character into the buffer. */ |
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426 |
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427 /* 0000 0000-0000 007F -> 0xxxxxxx */ |
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428 if (value <= 0x7F) { |
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429 *(parser->buffer.last++) = value; |
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430 } |
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431 /* 0000 0080-0000 07FF -> 110xxxxx 10xxxxxx */ |
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432 else if (value <= 0x7FF) { |
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433 *(parser->buffer.last++) = 0xC0 + (value >> 6); |
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434 *(parser->buffer.last++) = 0x80 + (value & 0x3F); |
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435 } |
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436 /* 0000 0800-0000 FFFF -> 1110xxxx 10xxxxxx 10xxxxxx */ |
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437 else if (value <= 0xFFFF) { |
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438 *(parser->buffer.last++) = 0xE0 + (value >> 12); |
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439 *(parser->buffer.last++) = 0x80 + ((value >> 6) & 0x3F); |
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440 *(parser->buffer.last++) = 0x80 + (value & 0x3F); |
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441 } |
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442 /* 0001 0000-0010 FFFF -> 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */ |
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443 else { |
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444 *(parser->buffer.last++) = 0xF0 + (value >> 18); |
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445 *(parser->buffer.last++) = 0x80 + ((value >> 12) & 0x3F); |
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446 *(parser->buffer.last++) = 0x80 + ((value >> 6) & 0x3F); |
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447 *(parser->buffer.last++) = 0x80 + (value & 0x3F); |
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448 } |
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449 |
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450 parser->unread ++; |
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451 } |
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452 |
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453 /* On EOF, put NUL into the buffer and return. */ |
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454 |
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455 if (parser->eof) { |
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456 *(parser->buffer.last++) = '\0'; |
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457 parser->unread ++; |
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458 return 1; |
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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 if (parser->offset >= PTRDIFF_MAX) |
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464 return yaml_parser_set_reader_error(parser, "input is too long", |
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465 PTRDIFF_MAX, -1); |
|
|
466 |
|
|
467 return 1; |
|
|
468 } |
|
|
469 |
