11 * Set the reader error and return 0.
15 yaml_parser_set_reader_error(yaml_parser_t *parser, const char *problem,
16 size_t offset, int value)
18 parser->error = YAML_READER_ERROR;
19 parser->problem = problem;
20 parser->problem_offset = offset;
21 parser->problem_value = value;
27 * Update the raw buffer.
31 yaml_parser_update_raw_buffer(yaml_parser_t *parser)
35 /* Return if the raw buffer is full. */
37 if (parser->raw_unread == YAML_RAW_BUFFER_SIZE) return 1;
41 if (parser->eof) return 1;
43 /* Move the remaining bytes in the raw buffer to the beginning. */
45 if (parser->raw_unread && parser->raw_buffer < parser->raw_pointer) {
46 memmove(parser->raw_buffer, parser->raw_pointer, parser->raw_unread);
48 parser->raw_pointer = parser->raw_buffer;
50 /* Call the read handler to fill the buffer. */
52 if (!parser->read_handler(parser->read_handler_data,
53 parser->raw_buffer + parser->raw_unread,
54 YAML_RAW_BUFFER_SIZE - parser->raw_unread,
56 return yaml_parser_set_reader_error(parser, "Input error",
59 parser->raw_unread += size_read;
68 * Determine the input stream encoding by checking the BOM symbol. If no BOM is
69 * found, the UTF-8 encoding is assumed. Return 1 on success, 0 on failure.
72 #define BOM_UTF8 "\xef\xbb\xbf"
73 #define BOM_UTF16LE "\xff\xfe"
74 #define BOM_UTF16BE "\xfe\xff"
77 yaml_parser_determine_encoding(yaml_parser_t *parser)
79 /* Ensure that we had enough bytes in the raw buffer. */
81 while (!parser->eof && parser->raw_unread < 3) {
82 if (!yaml_parser_update_raw_buffer(parser)) {
87 /* Determine the encoding. */
89 if (parser->raw_unread >= 2
90 && !memcmp(parser->raw_pointer, BOM_UTF16LE, 2)) {
91 parser->encoding = YAML_UTF16LE_ENCODING;
92 parser->raw_pointer += 2;
93 parser->raw_unread -= 2;
96 else if (parser->raw_unread >= 2
97 && !memcmp(parser->raw_pointer, BOM_UTF16BE, 2)) {
98 parser->encoding = YAML_UTF16BE_ENCODING;
99 parser->raw_pointer += 2;
100 parser->raw_unread -= 2;
103 else if (parser->raw_unread >= 3
104 && !memcmp(parser->raw_pointer, BOM_UTF8, 3)) {
105 parser->encoding = YAML_UTF8_ENCODING;
106 parser->raw_pointer += 3;
107 parser->raw_unread -= 3;
111 parser->encoding = YAML_UTF8_ENCODING;
118 * Ensure that the buffer contains at least length characters.
119 * Return 1 on success, 0 on failure.
121 * The length is supposed to be significantly less that the buffer size.
125 yaml_parser_update_buffer(yaml_parser_t *parser, size_t length)
127 /* If the EOF flag is set and the raw buffer is empty, do nothing. */
129 if (parser->eof && !parser->raw_unread)
132 /* Return if the buffer contains enough characters. */
134 if (parser->unread >= length)
137 /* Determine the input encoding if it is not known yet. */
139 if (!parser->encoding) {
140 if (!yaml_parser_determine_encoding(parser))
144 /* Move the unread characters to the beginning of the buffer. */
146 if (parser->buffer < parser->pointer
147 && parser->pointer < parser->buffer_end) {
148 size_t size = parser->buffer_end - parser->pointer;
149 memmove(parser->buffer, parser->pointer, size);
150 parser->pointer = parser->buffer;
151 parser->buffer_end = parser->buffer + size;
153 else if (parser->pointer == parser->buffer_end) {
154 parser->pointer = parser->buffer;
155 parser->buffer_end = parser->buffer;
158 /* Fill the buffer until it has enough characters. */
160 while (parser->unread < length)
162 /* Fill the raw buffer. */
164 if (!yaml_parser_update_raw_buffer(parser)) return 0;
166 /* Decode the raw buffer. */
168 while (parser->raw_unread)
170 unsigned int value, value2;
176 /* Decode the next character. */
178 switch (parser->encoding)
180 case YAML_UTF8_ENCODING:
183 * Decode a UTF-8 character. Check RFC 3629
184 * (http://www.ietf.org/rfc/rfc3629.txt) for more details.
186 * The following table (taken from the RFC) is used for
189 * Char. number range | UTF-8 octet sequence
190 * (hexadecimal) | (binary)
191 * --------------------+------------------------------------
192 * 0000 0000-0000 007F | 0xxxxxxx
193 * 0000 0080-0000 07FF | 110xxxxx 10xxxxxx
194 * 0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx
195 * 0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
197 * Additionally, the characters in the range 0xD800-0xDFFF
198 * are prohibited as they are reserved for use with UTF-16
202 /* Determine the length of the UTF-8 sequence. */
204 octet = parser->raw_pointer[0];
205 width = (octet & 0x80) == 0x00 ? 1 :
206 (octet & 0xE0) == 0xC0 ? 2 :
207 (octet & 0xF0) == 0xE0 ? 3 :
208 (octet & 0xF8) == 0xF0 ? 4 : 0;
210 /* Check if the leading octet is valid. */
213 return yaml_parser_set_reader_error(parser,
214 "Invalid leading UTF-8 octet",
215 parser->offset, octet);
217 /* Check if the raw buffer contains an incomplete character. */
219 if (width > parser->raw_unread) {
221 return yaml_parser_set_reader_error(parser,
222 "Incomplete UTF-8 octet sequence",
229 /* Decode the leading octet. */
231 value = (octet & 0x80) == 0x00 ? octet & 0x7F :
232 (octet & 0xE0) == 0xC0 ? octet & 0x1F :
233 (octet & 0xF0) == 0xE0 ? octet & 0x0F :
234 (octet & 0xF8) == 0xF0 ? octet & 0x07 : 0;
236 /* Check and decode the trailing octets. */
238 for (k = 1; k < width; k ++)
240 octet = parser->raw_pointer[k];
242 /* Check if the octet is valid. */
244 if ((octet & 0xC0) != 0x80)
245 return yaml_parser_set_reader_error(parser,
246 "Invalid trailing UTF-8 octet",
247 parser->offset+k, octet);
249 /* Decode the octet. */
251 value = (value << 6) + (octet & 0x3F);
254 /* Check the length of the sequence against the value. */
256 if (!((width == 1) ||
257 (width == 2 && value >= 0x80) ||
258 (width == 3 && value >= 0x800) ||
259 (width == 4 && value >= 0x10000)))
260 return yaml_parser_set_reader_error(parser,
261 "Invalid length of a UTF-8 sequence",
264 /* Check the range of the value. */
266 if ((value >= 0xD800 && value <= 0xDFFF) || value > 0x10FFFF)
267 return yaml_parser_set_reader_error(parser,
268 "Invalid Unicode character",
269 parser->offset, value);
273 case YAML_UTF16LE_ENCODING:
274 case YAML_UTF16BE_ENCODING:
276 low = (parser->encoding == YAML_UTF16LE_ENCODING ? 0 : 1);
277 high = (parser->encoding == YAML_UTF16LE_ENCODING ? 1 : 0);
280 * The UTF-16 encoding is not as simple as one might
281 * naively think. Check RFC 2781
282 * (http://www.ietf.org/rfc/rfc2781.txt).
284 * Normally, two subsequent bytes describe a Unicode
285 * character. However a special technique (called a
286 * surrogate pair) is used for specifying character
287 * values larger than 0xFFFF.
289 * A surrogate pair consists of two pseudo-characters:
290 * high surrogate area (0xD800-0xDBFF)
291 * low surrogate area (0xDC00-0xDFFF)
293 * The following formulas are used for decoding
294 * and encoding characters using surrogate pairs:
296 * U = U' + 0x10000 (0x01 00 00 <= U <= 0x10 FF FF)
297 * U' = yyyyyyyyyyxxxxxxxxxx (0 <= U' <= 0x0F FF FF)
298 * W1 = 110110yyyyyyyyyy
299 * W2 = 110111xxxxxxxxxx
301 * where U is the character value, W1 is the high surrogate
302 * area, W2 is the low surrogate area.
305 /* Check for incomplete UTF-16 character. */
307 if (parser->raw_unread < 2) {
309 return yaml_parser_set_reader_error(parser,
310 "Incomplete UTF-16 character",
317 /* Get the character. */
319 value = parser->raw_pointer[low]
320 + (parser->raw_pointer[high] << 8);
322 /* Check for unexpected low surrogate area. */
324 if ((value & 0xFC00) == 0xDC00)
325 return yaml_parser_set_reader_error(parser,
326 "Unexpected low surrogate area",
327 parser->offset, value);
329 /* Check for a high surrogate area. */
331 if ((value & 0xFC00) == 0xD800) {
335 /* Check for incomplete surrogate pair. */
337 if (parser->raw_unread < 4) {
339 return yaml_parser_set_reader_error(parser,
340 "Incomplete UTF-16 surrogate pair",
347 /* Get the next character. */
349 unsigned int value2 = parser->raw_pointer[low+2]
350 + (parser->raw_pointer[high+2] << 8);
352 /* Check for a low surrogate area. */
354 if ((value2 & 0xFC00) != 0xDC00)
355 return yaml_parser_set_reader_error(parser,
356 "Expected low surrogate area",
357 parser->offset+2, value2);
359 /* Generate the value of the surrogate pair. */
361 value = 0x10000 + ((value & 0x3FF) << 10) + (value2 & 0x3FF);
371 /* Check if the raw buffer contains enough bytes to form a character. */
373 if (incomplete) break;
376 * Check if the character is in the allowed range:
377 * #x9 | #xA | #xD | [#x20-#x7E] (8 bit)
378 * | #x85 | [#xA0-#xD7FF] | [#xE000-#xFFFD] (16 bit)
379 * | [#x10000-#x10FFFF] (32 bit)
382 if (! (value == 0x09 || value == 0x0A || value == 0x0D
383 || (value >= 0x20 && value <= 0x7E)
384 || (value == 0x85) || (value >= 0xA0 && value <= 0xD7FF)
385 || (value >= 0xE000 && value <= 0xFFFD)
386 || (value >= 0x10000 && value <= 0x10FFFF)))
387 return yaml_parser_set_reader_error(parser,
388 "Control characters are not allowed",
389 parser->offset, value);
391 /* Move the raw pointers. */
393 parser->raw_pointer += width;
394 parser->raw_unread -= width;
395 parser->offset += width;
397 /* Finally put the character into the buffer. */
399 /* 0000 0000-0000 007F -> 0xxxxxxx */
401 *(parser->buffer_end++) = value;
403 /* 0000 0080-0000 07FF -> 110xxxxx 10xxxxxx */
404 else if (value <= 0x7FF) {
405 *(parser->buffer_end++) = 0xC0 + (value >> 6);
406 *(parser->buffer_end++) = 0x80 + (value & 0x3F);
408 /* 0000 0800-0000 FFFF -> 1110xxxx 10xxxxxx 10xxxxxx */
409 else if (value <= 0xFFFF) {
410 *(parser->buffer_end++) = 0xE0 + (value >> 12);
411 *(parser->buffer_end++) = 0x80 + ((value >> 6) & 0x3F);
412 *(parser->buffer_end++) = 0x80 + (value & 0x3F);
414 /* 0001 0000-0010 FFFF -> 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
416 *(parser->buffer_end++) = 0xF0 + (value >> 18);
417 *(parser->buffer_end++) = 0x80 + ((value >> 12) & 0x3F);
418 *(parser->buffer_end++) = 0x80 + ((value >> 6) & 0x3F);
419 *(parser->buffer_end++) = 0x80 + (value & 0x3F);
425 /* On EOF, put NUL into the buffer and return. */
428 *(parser->buffer_end++) = '\0';