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ffi/reader.c  view on Meta::CPAN

                            (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. */