470 lines
16 KiB
C
470 lines
16 KiB
C
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#include "yaml_private.h"
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/*
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* Declarations.
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*/
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static int
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yaml_parser_set_reader_error(yaml_parser_t *parser, const char *problem,
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size_t offset, int value);
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static int
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yaml_parser_update_raw_buffer(yaml_parser_t *parser);
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static int
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yaml_parser_determine_encoding(yaml_parser_t *parser);
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YAML_DECLARE(int)
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yaml_parser_update_buffer(yaml_parser_t *parser, size_t length);
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/*
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* Set the reader error and return 0.
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*/
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static int
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yaml_parser_set_reader_error(yaml_parser_t *parser, const char *problem,
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size_t offset, int value)
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{
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parser->error = YAML_READER_ERROR;
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parser->problem = problem;
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parser->problem_offset = offset;
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parser->problem_value = value;
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return 0;
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}
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/*
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* Byte order marks.
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*/
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#define BOM_UTF8 "\xef\xbb\xbf"
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#define BOM_UTF16LE "\xff\xfe"
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#define BOM_UTF16BE "\xfe\xff"
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/*
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* Determine the input stream encoding by checking the BOM symbol. If no BOM is
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* found, the UTF-8 encoding is assumed. Return 1 on success, 0 on failure.
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*/
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static int
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yaml_parser_determine_encoding(yaml_parser_t *parser)
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{
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/* Ensure that we had enough bytes in the raw buffer. */
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while (!parser->eof
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&& parser->raw_buffer.last - parser->raw_buffer.pointer < 3) {
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if (!yaml_parser_update_raw_buffer(parser)) {
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return 0;
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}
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}
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/* Determine the encoding. */
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if (parser->raw_buffer.last - parser->raw_buffer.pointer >= 2
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&& !memcmp(parser->raw_buffer.pointer, BOM_UTF16LE, 2)) {
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parser->encoding = YAML_UTF16LE_ENCODING;
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parser->raw_buffer.pointer += 2;
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parser->offset += 2;
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}
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else if (parser->raw_buffer.last - parser->raw_buffer.pointer >= 2
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&& !memcmp(parser->raw_buffer.pointer, BOM_UTF16BE, 2)) {
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parser->encoding = YAML_UTF16BE_ENCODING;
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parser->raw_buffer.pointer += 2;
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parser->offset += 2;
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}
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else if (parser->raw_buffer.last - parser->raw_buffer.pointer >= 3
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&& !memcmp(parser->raw_buffer.pointer, BOM_UTF8, 3)) {
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parser->encoding = YAML_UTF8_ENCODING;
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parser->raw_buffer.pointer += 3;
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parser->offset += 3;
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}
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else {
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parser->encoding = YAML_UTF8_ENCODING;
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}
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return 1;
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}
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/*
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* Update the raw buffer.
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*/
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static int
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yaml_parser_update_raw_buffer(yaml_parser_t *parser)
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{
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size_t size_read = 0;
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/* Return if the raw buffer is full. */
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if (parser->raw_buffer.start == parser->raw_buffer.pointer
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&& parser->raw_buffer.last == parser->raw_buffer.end)
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return 1;
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/* Return on EOF. */
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if (parser->eof) return 1;
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/* Move the remaining bytes in the raw buffer to the beginning. */
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if (parser->raw_buffer.start < parser->raw_buffer.pointer
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&& parser->raw_buffer.pointer < parser->raw_buffer.last) {
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memmove(parser->raw_buffer.start, parser->raw_buffer.pointer,
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parser->raw_buffer.last - parser->raw_buffer.pointer);
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}
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parser->raw_buffer.last -=
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parser->raw_buffer.pointer - parser->raw_buffer.start;
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parser->raw_buffer.pointer = parser->raw_buffer.start;
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/* Call the read handler to fill the buffer. */
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if (!parser->read_handler(parser->read_handler_data, parser->raw_buffer.last,
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parser->raw_buffer.end - parser->raw_buffer.last, &size_read)) {
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return yaml_parser_set_reader_error(parser, "input error",
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parser->offset, -1);
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}
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parser->raw_buffer.last += size_read;
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if (!size_read) {
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parser->eof = 1;
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}
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return 1;
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}
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/*
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* Ensure that the buffer contains at least `length` characters.
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* Return 1 on success, 0 on failure.
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*
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* The length is supposed to be significantly less that the buffer size.
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*/
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YAML_DECLARE(int)
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yaml_parser_update_buffer(yaml_parser_t *parser, size_t length)
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{
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int first = 1;
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assert(parser->read_handler); /* Read handler must be set. */
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/* If the EOF flag is set and the raw buffer is empty, do nothing. */
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if (parser->eof && parser->raw_buffer.pointer == parser->raw_buffer.last)
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return 1;
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/* Return if the buffer contains enough characters. */
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if (parser->unread >= length)
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return 1;
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/* Determine the input encoding if it is not known yet. */
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if (!parser->encoding) {
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if (!yaml_parser_determine_encoding(parser))
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return 0;
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}
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/* Move the unread characters to the beginning of the buffer. */
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if (parser->buffer.start < parser->buffer.pointer
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&& parser->buffer.pointer < parser->buffer.last) {
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size_t size = parser->buffer.last - parser->buffer.pointer;
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memmove(parser->buffer.start, parser->buffer.pointer, size);
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parser->buffer.pointer = parser->buffer.start;
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parser->buffer.last = parser->buffer.start + size;
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}
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else if (parser->buffer.pointer == parser->buffer.last) {
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parser->buffer.pointer = parser->buffer.start;
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parser->buffer.last = parser->buffer.start;
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}
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/* Fill the buffer until it has enough characters. */
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while (parser->unread < length)
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{
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/* Fill the raw buffer if necessary. */
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if (!first || parser->raw_buffer.pointer == parser->raw_buffer.last) {
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if (!yaml_parser_update_raw_buffer(parser)) return 0;
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}
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first = 0;
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/* Decode the raw buffer. */
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while (parser->raw_buffer.pointer != parser->raw_buffer.last)
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{
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unsigned int value = 0, value2 = 0;
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int incomplete = 0;
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unsigned char octet;
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unsigned int width = 0;
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int low, high;
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size_t k;
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size_t raw_unread = parser->raw_buffer.last - parser->raw_buffer.pointer;
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/* Decode the next character. */
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switch (parser->encoding)
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{
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case YAML_UTF8_ENCODING:
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/*
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* Decode a UTF-8 character. Check RFC 3629
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* (http://www.ietf.org/rfc/rfc3629.txt) for more details.
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*
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* The following table (taken from the RFC) is used for
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* decoding.
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*
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* Char. number range | UTF-8 octet sequence
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* (hexadecimal) | (binary)
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* --------------------+------------------------------------
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* 0000 0000-0000 007F | 0xxxxxxx
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* 0000 0080-0000 07FF | 110xxxxx 10xxxxxx
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* 0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx
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* 0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
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*
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* Additionally, the characters in the range 0xD800-0xDFFF
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* are prohibited as they are reserved for use with UTF-16
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* surrogate pairs.
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*/
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/* Determine the length of the UTF-8 sequence. */
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octet = parser->raw_buffer.pointer[0];
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width = (octet & 0x80) == 0x00 ? 1 :
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(octet & 0xE0) == 0xC0 ? 2 :
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(octet & 0xF0) == 0xE0 ? 3 :
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(octet & 0xF8) == 0xF0 ? 4 : 0;
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/* Check if the leading octet is valid. */
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if (!width)
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return yaml_parser_set_reader_error(parser,
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"invalid leading UTF-8 octet",
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parser->offset, octet);
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/* Check if the raw buffer contains an incomplete character. */
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if (width > raw_unread) {
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if (parser->eof) {
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return yaml_parser_set_reader_error(parser,
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"incomplete UTF-8 octet sequence",
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parser->offset, -1);
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}
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incomplete = 1;
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break;
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}
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/* Decode the leading octet. */
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value = (octet & 0x80) == 0x00 ? octet & 0x7F :
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(octet & 0xE0) == 0xC0 ? octet & 0x1F :
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(octet & 0xF0) == 0xE0 ? octet & 0x0F :
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(octet & 0xF8) == 0xF0 ? octet & 0x07 : 0;
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/* Check and decode the trailing octets. */
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for (k = 1; k < width; k ++)
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{
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octet = parser->raw_buffer.pointer[k];
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/* Check if the octet is valid. */
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if ((octet & 0xC0) != 0x80)
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return yaml_parser_set_reader_error(parser,
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"invalid trailing UTF-8 octet",
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parser->offset+k, octet);
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/* Decode the octet. */
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value = (value << 6) + (octet & 0x3F);
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}
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/* Check the length of the sequence against the value. */
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if (!((width == 1) ||
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(width == 2 && value >= 0x80) ||
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(width == 3 && value >= 0x800) ||
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(width == 4 && value >= 0x10000)))
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return yaml_parser_set_reader_error(parser,
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"invalid length of a UTF-8 sequence",
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parser->offset, -1);
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/* Check the range of the value. */
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if ((value >= 0xD800 && value <= 0xDFFF) || value > 0x10FFFF)
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return yaml_parser_set_reader_error(parser,
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"invalid Unicode character",
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parser->offset, value);
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break;
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case YAML_UTF16LE_ENCODING:
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case YAML_UTF16BE_ENCODING:
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low = (parser->encoding == YAML_UTF16LE_ENCODING ? 0 : 1);
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high = (parser->encoding == YAML_UTF16LE_ENCODING ? 1 : 0);
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/*
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* The UTF-16 encoding is not as simple as one might
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* naively think. Check RFC 2781
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* (http://www.ietf.org/rfc/rfc2781.txt).
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*
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* Normally, two subsequent bytes describe a Unicode
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* character. However a special technique (called a
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* surrogate pair) is used for specifying character
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* values larger than 0xFFFF.
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*
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* A surrogate pair consists of two pseudo-characters:
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* high surrogate area (0xD800-0xDBFF)
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* low surrogate area (0xDC00-0xDFFF)
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*
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* The following formulas are used for decoding
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* and encoding characters using surrogate pairs:
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*
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* U = U' + 0x10000 (0x01 00 00 <= U <= 0x10 FF FF)
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* U' = yyyyyyyyyyxxxxxxxxxx (0 <= U' <= 0x0F FF FF)
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* W1 = 110110yyyyyyyyyy
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* W2 = 110111xxxxxxxxxx
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*
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* where U is the character value, W1 is the high surrogate
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* area, W2 is the low surrogate area.
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*/
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/* Check for incomplete UTF-16 character. */
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if (raw_unread < 2) {
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if (parser->eof) {
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return yaml_parser_set_reader_error(parser,
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"incomplete UTF-16 character",
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parser->offset, -1);
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}
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incomplete = 1;
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break;
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}
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/* Get the character. */
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value = parser->raw_buffer.pointer[low]
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+ (parser->raw_buffer.pointer[high] << 8);
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/* Check for unexpected low surrogate area. */
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if ((value & 0xFC00) == 0xDC00)
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return yaml_parser_set_reader_error(parser,
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"unexpected low surrogate area",
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parser->offset, value);
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/* Check for a high surrogate area. */
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if ((value & 0xFC00) == 0xD800) {
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width = 4;
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/* Check for incomplete surrogate pair. */
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if (raw_unread < 4) {
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if (parser->eof) {
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return yaml_parser_set_reader_error(parser,
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"incomplete UTF-16 surrogate pair",
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parser->offset, -1);
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}
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incomplete = 1;
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break;
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}
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/* Get the next character. */
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value2 = parser->raw_buffer.pointer[low+2]
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+ (parser->raw_buffer.pointer[high+2] << 8);
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/* Check for a low surrogate area. */
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if ((value2 & 0xFC00) != 0xDC00)
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return yaml_parser_set_reader_error(parser,
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"expected low surrogate area",
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parser->offset+2, value2);
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/* Generate the value of the surrogate pair. */
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value = 0x10000 + ((value & 0x3FF) << 10) + (value2 & 0x3FF);
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}
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else {
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width = 2;
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}
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break;
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default:
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assert(1); /* Impossible. */
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}
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/* Check if the raw buffer contains enough bytes to form a character. */
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if (incomplete) break;
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/*
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* Check if the character is in the allowed range:
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* #x9 | #xA | #xD | [#x20-#x7E] (8 bit)
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* | #x85 | [#xA0-#xD7FF] | [#xE000-#xFFFD] (16 bit)
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* | [#x10000-#x10FFFF] (32 bit)
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*/
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if (! (value == 0x09 || value == 0x0A || value == 0x0D
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|| (value >= 0x20 && value <= 0x7E)
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|| (value == 0x85) || (value >= 0xA0 && value <= 0xD7FF)
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|| (value >= 0xE000 && value <= 0xFFFD)
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|| (value >= 0x10000 && value <= 0x10FFFF)))
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return yaml_parser_set_reader_error(parser,
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"control characters are not allowed",
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parser->offset, value);
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/* Move the raw pointers. */
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parser->raw_buffer.pointer += width;
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parser->offset += width;
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/* Finally put the character into the buffer. */
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/* 0000 0000-0000 007F -> 0xxxxxxx */
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if (value <= 0x7F) {
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*(parser->buffer.last++) = value;
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}
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/* 0000 0080-0000 07FF -> 110xxxxx 10xxxxxx */
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else if (value <= 0x7FF) {
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*(parser->buffer.last++) = 0xC0 + (value >> 6);
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*(parser->buffer.last++) = 0x80 + (value & 0x3F);
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}
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/* 0000 0800-0000 FFFF -> 1110xxxx 10xxxxxx 10xxxxxx */
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else if (value <= 0xFFFF) {
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*(parser->buffer.last++) = 0xE0 + (value >> 12);
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*(parser->buffer.last++) = 0x80 + ((value >> 6) & 0x3F);
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*(parser->buffer.last++) = 0x80 + (value & 0x3F);
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}
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/* 0001 0000-0010 FFFF -> 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
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else {
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*(parser->buffer.last++) = 0xF0 + (value >> 18);
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*(parser->buffer.last++) = 0x80 + ((value >> 12) & 0x3F);
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*(parser->buffer.last++) = 0x80 + ((value >> 6) & 0x3F);
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*(parser->buffer.last++) = 0x80 + (value & 0x3F);
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}
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parser->unread ++;
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}
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/* On EOF, put NUL into the buffer and return. */
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if (parser->eof) {
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*(parser->buffer.last++) = '\0';
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parser->unread ++;
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return 1;
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}
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}
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if (parser->offset >= MAX_FILE_SIZE) {
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return yaml_parser_set_reader_error(parser, "input is too long",
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parser->offset, -1);
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}
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return 1;
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}
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