+ /* Decode the raw buffer. */
+
+ while (parser->raw_buffer.pointer != parser->raw_buffer.last)
+ {
+ unsigned int value = 0, value2 = 0;
+ int incomplete = 0;
+ unsigned char octet;
+ unsigned int width = 0;
+ int low, high;
+ size_t k;
+ size_t raw_unread = parser->raw_buffer.last - parser->raw_buffer.pointer;
+
+ /* Decode the next character. */
+
+ switch (parser->encoding)
+ {
+ case YAML_UTF8_ENCODING:
+
+ /*
+ * Decode a UTF-8 character. Check RFC 3629
+ * (http://www.ietf.org/rfc/rfc3629.txt) for more details.
+ *
+ * The following table (taken from the RFC) is used for
+ * decoding.
+ *
+ * Char. number range | UTF-8 octet sequence
+ * (hexadecimal) | (binary)
+ * --------------------+------------------------------------
+ * 0000 0000-0000 007F | 0xxxxxxx
+ * 0000 0080-0000 07FF | 110xxxxx 10xxxxxx
+ * 0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx
+ * 0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+ *
+ * Additionally, the characters in the range 0xD800-0xDFFF
+ * are prohibited as they are reserved for use with UTF-16
+ * surrogate pairs.
+ */
+
+ /* Determine the length of the UTF-8 sequence. */
+
+ octet = parser->raw_buffer.pointer[0];
+ width = (octet & 0x80) == 0x00 ? 1 :
+ (octet & 0xE0) == 0xC0 ? 2 :
+ (octet & 0xF0) == 0xE0 ? 3 :
+ (octet & 0xF8) == 0xF0 ? 4 : 0;
+
+ /* Check if the leading octet is valid. */
+
+ if (!width)
+ return yaml_parser_set_reader_error(parser,
+ "invalid leading UTF-8 octet",
+ parser->offset, octet);
+
+ /* Check if the raw buffer contains an incomplete character. */
+
+ if (width > raw_unread) {
+ if (parser->eof) {
+ return yaml_parser_set_reader_error(parser,
+ "incomplete UTF-8 octet sequence",
+ parser->offset, -1);
+ }
+ incomplete = 1;
+ break;
+ }
+
+ /* Decode the leading octet. */
+
+ value = (octet & 0x80) == 0x00 ? octet & 0x7F :
+ (octet & 0xE0) == 0xC0 ? octet & 0x1F :
+ (octet & 0xF0) == 0xE0 ? octet & 0x0F :
+ (octet & 0xF8) == 0xF0 ? octet & 0x07 : 0;
+
+ /* Check and decode the trailing octets. */
+
+ for (k = 1; k < width; k ++)
+ {
+ octet = parser->raw_buffer.pointer[k];
+
+ /* Check if the octet is valid. */
+
+ if ((octet & 0xC0) != 0x80)
+ return yaml_parser_set_reader_error(parser,
+ "invalid trailing UTF-8 octet",
+ parser->offset+k, octet);
+
+ /* Decode the octet. */
+
+ value = (value << 6) + (octet & 0x3F);
+ }
+
+ /* Check the length of the sequence against the value. */
+
+ if (!((width == 1) ||
+ (width == 2 && value >= 0x80) ||
+ (width == 3 && value >= 0x800) ||
+ (width == 4 && value >= 0x10000)))
+ return yaml_parser_set_reader_error(parser,
+ "invalid length of a UTF-8 sequence",
+ parser->offset, -1);
+
+ /* Check the range of the value. */
+
+ if ((value >= 0xD800 && value <= 0xDFFF) || value > 0x10FFFF)
+ return yaml_parser_set_reader_error(parser,
+ "invalid Unicode character",
+ parser->offset, value);
+
+ break;
+
+ case YAML_UTF16LE_ENCODING:
+ case YAML_UTF16BE_ENCODING:
+
+ low = (parser->encoding == YAML_UTF16LE_ENCODING ? 0 : 1);
+ high = (parser->encoding == YAML_UTF16LE_ENCODING ? 1 : 0);
+
+ /*
+ * The UTF-16 encoding is not as simple as one might
+ * naively think. Check RFC 2781
+ * (http://www.ietf.org/rfc/rfc2781.txt).
+ *
+ * Normally, two subsequent bytes describe a Unicode
+ * character. However a special technique (called a
+ * surrogate pair) is used for specifying character
+ * values larger than 0xFFFF.
+ *
+ * A surrogate pair consists of two pseudo-characters:
+ * high surrogate area (0xD800-0xDBFF)
+ * low surrogate area (0xDC00-0xDFFF)
+ *
+ * The following formulas are used for decoding
+ * and encoding characters using surrogate pairs:
+ *
+ * U = U' + 0x10000 (0x01 00 00 <= U <= 0x10 FF FF)
+ * U' = yyyyyyyyyyxxxxxxxxxx (0 <= U' <= 0x0F FF FF)
+ * W1 = 110110yyyyyyyyyy
+ * W2 = 110111xxxxxxxxxx
+ *
+ * where U is the character value, W1 is the high surrogate
+ * area, W2 is the low surrogate area.
+ */
+
+ /* Check for incomplete UTF-16 character. */
+
+ if (raw_unread < 2) {
+ if (parser->eof) {
+ return yaml_parser_set_reader_error(parser,
+ "incomplete UTF-16 character",
+ parser->offset, -1);
+ }
+ incomplete = 1;
+ break;
+ }
+
+ /* Get the character. */
+
+ value = parser->raw_buffer.pointer[low]
+ + (parser->raw_buffer.pointer[high] << 8);
+
+ /* Check for unexpected low surrogate area. */
+
+ if ((value & 0xFC00) == 0xDC00)
+ return yaml_parser_set_reader_error(parser,
+ "unexpected low surrogate area",
+ parser->offset, value);
+
+ /* Check for a high surrogate area. */
+
+ if ((value & 0xFC00) == 0xD800) {
+
+ width = 4;
+
+ /* Check for incomplete surrogate pair. */
+
+ if (raw_unread < 4) {
+ if (parser->eof) {
+ return yaml_parser_set_reader_error(parser,
+ "incomplete UTF-16 surrogate pair",
+ parser->offset, -1);
+ }
+ incomplete = 1;
+ break;
+ }
+
+ /* Get the next character. */
+
+ value2 = parser->raw_buffer.pointer[low+2]
+ + (parser->raw_buffer.pointer[high+2] << 8);
+
+ /* Check for a low surrogate area. */
+
+ if ((value2 & 0xFC00) != 0xDC00)
+ return yaml_parser_set_reader_error(parser,
+ "expected low surrogate area",
+ parser->offset+2, value2);
+
+ /* Generate the value of the surrogate pair. */
+
+ value = 0x10000 + ((value & 0x3FF) << 10) + (value2 & 0x3FF);
+ }
+
+ else {
+ width = 2;
+ }
+
+ break;
+
+ default:
+ assert(1); /* Impossible. */
+ }
+
+ /* Check if the raw buffer contains enough bytes to form a character. */
+
+ if (incomplete) break;
+
+ /*
+ * Check if the character is in the allowed range:
+ * #x9 | #xA | #xD | [#x20-#x7E] (8 bit)
+ * | #x85 | [#xA0-#xD7FF] | [#xE000-#xFFFD] (16 bit)
+ * | [#x10000-#x10FFFF] (32 bit)
+ */
+
+ if (! (value == 0x09 || value == 0x0A || value == 0x0D
+ || (value >= 0x20 && value <= 0x7E)
+ || (value == 0x85) || (value >= 0xA0 && value <= 0xD7FF)
+ || (value >= 0xE000 && value <= 0xFFFD)
+ || (value >= 0x10000 && value <= 0x10FFFF)))
+ return yaml_parser_set_reader_error(parser,
+ "control characters are not allowed",
+ parser->offset, value);
+
+ /* Move the raw pointers. */
+
+ parser->raw_buffer.pointer += width;
+ parser->offset += width;
+
+ /* Finally put the character into the buffer. */
+
+ /* 0000 0000-0000 007F -> 0xxxxxxx */
+ if (value <= 0x7F) {
+ *(parser->buffer.last++) = value;
+ }
+ /* 0000 0080-0000 07FF -> 110xxxxx 10xxxxxx */
+ else if (value <= 0x7FF) {
+ *(parser->buffer.last++) = 0xC0 + (value >> 6);
+ *(parser->buffer.last++) = 0x80 + (value & 0x3F);
+ }
+ /* 0000 0800-0000 FFFF -> 1110xxxx 10xxxxxx 10xxxxxx */
+ else if (value <= 0xFFFF) {
+ *(parser->buffer.last++) = 0xE0 + (value >> 12);
+ *(parser->buffer.last++) = 0x80 + ((value >> 6) & 0x3F);
+ *(parser->buffer.last++) = 0x80 + (value & 0x3F);
+ }
+ /* 0001 0000-0010 FFFF -> 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
+ else {
+ *(parser->buffer.last++) = 0xF0 + (value >> 18);
+ *(parser->buffer.last++) = 0x80 + ((value >> 12) & 0x3F);
+ *(parser->buffer.last++) = 0x80 + ((value >> 6) & 0x3F);
+ *(parser->buffer.last++) = 0x80 + (value & 0x3F);
+ }
+
+ parser->unread ++;
+ }
+
+ /* On EOF, put NUL into the buffer and return. */
+
+ if (parser->eof) {
+ *(parser->buffer.last++) = '\0';
+ parser->unread ++;
+ return 1;
+ }
+
+ }
+
+ if (parser->offset >= PTRDIFF_MAX)
+ return yaml_parser_set_reader_error(parser, "input is too long",
+ PTRDIFF_MAX, -1);
+
+ return 1;
+}