|
- package yaml
-
- import (
- "io"
- )
-
- // Set the reader error and return 0.
- func yaml_parser_set_reader_error(parser *yaml_parser_t, problem string, offset int, value int) bool {
- parser.error = yaml_READER_ERROR
- parser.problem = problem
- parser.problem_offset = offset
- parser.problem_value = value
- return false
- }
-
- // Byte order marks.
- const (
- bom_UTF8 = "\xef\xbb\xbf"
- bom_UTF16LE = "\xff\xfe"
- bom_UTF16BE = "\xfe\xff"
- )
-
- // Determine the input stream encoding by checking the BOM symbol. If no BOM is
- // found, the UTF-8 encoding is assumed. Return 1 on success, 0 on failure.
- func yaml_parser_determine_encoding(parser *yaml_parser_t) bool {
- // Ensure that we had enough bytes in the raw buffer.
- for !parser.eof && len(parser.raw_buffer)-parser.raw_buffer_pos < 3 {
- if !yaml_parser_update_raw_buffer(parser) {
- return false
- }
- }
-
- // Determine the encoding.
- buf := parser.raw_buffer
- pos := parser.raw_buffer_pos
- avail := len(buf) - pos
- if avail >= 2 && buf[pos] == bom_UTF16LE[0] && buf[pos+1] == bom_UTF16LE[1] {
- parser.encoding = yaml_UTF16LE_ENCODING
- parser.raw_buffer_pos += 2
- parser.offset += 2
- } else if avail >= 2 && buf[pos] == bom_UTF16BE[0] && buf[pos+1] == bom_UTF16BE[1] {
- parser.encoding = yaml_UTF16BE_ENCODING
- parser.raw_buffer_pos += 2
- parser.offset += 2
- } else if avail >= 3 && buf[pos] == bom_UTF8[0] && buf[pos+1] == bom_UTF8[1] && buf[pos+2] == bom_UTF8[2] {
- parser.encoding = yaml_UTF8_ENCODING
- parser.raw_buffer_pos += 3
- parser.offset += 3
- } else {
- parser.encoding = yaml_UTF8_ENCODING
- }
- return true
- }
-
- // Update the raw buffer.
- func yaml_parser_update_raw_buffer(parser *yaml_parser_t) bool {
- size_read := 0
-
- // Return if the raw buffer is full.
- if parser.raw_buffer_pos == 0 && len(parser.raw_buffer) == cap(parser.raw_buffer) {
- return true
- }
-
- // Return on EOF.
- if parser.eof {
- return true
- }
-
- // Move the remaining bytes in the raw buffer to the beginning.
- if parser.raw_buffer_pos > 0 && parser.raw_buffer_pos < len(parser.raw_buffer) {
- copy(parser.raw_buffer, parser.raw_buffer[parser.raw_buffer_pos:])
- }
- parser.raw_buffer = parser.raw_buffer[:len(parser.raw_buffer)-parser.raw_buffer_pos]
- parser.raw_buffer_pos = 0
-
- // Call the read handler to fill the buffer.
- size_read, err := parser.read_handler(parser, parser.raw_buffer[len(parser.raw_buffer):cap(parser.raw_buffer)])
- parser.raw_buffer = parser.raw_buffer[:len(parser.raw_buffer)+size_read]
- if err == io.EOF {
- parser.eof = true
- } else if err != nil {
- return yaml_parser_set_reader_error(parser, "input error: "+err.Error(), parser.offset, -1)
- }
- return true
- }
-
- // Ensure that the buffer contains at least `length` characters.
- // Return true on success, false on failure.
- //
- // The length is supposed to be significantly less that the buffer size.
- func yaml_parser_update_buffer(parser *yaml_parser_t, length int) bool {
- if parser.read_handler == nil {
- panic("read handler must be set")
- }
-
- // [Go] This function was changed to guarantee the requested length size at EOF.
- // The fact we need to do this is pretty awful, but the description above implies
- // for that to be the case, and there are tests
-
- // If the EOF flag is set and the raw buffer is empty, do nothing.
- if parser.eof && parser.raw_buffer_pos == len(parser.raw_buffer) {
- // [Go] ACTUALLY! Read the documentation of this function above.
- // This is just broken. To return true, we need to have the
- // given length in the buffer. Not doing that means every single
- // check that calls this function to make sure the buffer has a
- // given length is Go) panicking; or C) accessing invalid memory.
- //return true
- }
-
- // Return if the buffer contains enough characters.
- if parser.unread >= length {
- return true
- }
-
- // Determine the input encoding if it is not known yet.
- if parser.encoding == yaml_ANY_ENCODING {
- if !yaml_parser_determine_encoding(parser) {
- return false
- }
- }
-
- // Move the unread characters to the beginning of the buffer.
- buffer_len := len(parser.buffer)
- if parser.buffer_pos > 0 && parser.buffer_pos < buffer_len {
- copy(parser.buffer, parser.buffer[parser.buffer_pos:])
- buffer_len -= parser.buffer_pos
- parser.buffer_pos = 0
- } else if parser.buffer_pos == buffer_len {
- buffer_len = 0
- parser.buffer_pos = 0
- }
-
- // Open the whole buffer for writing, and cut it before returning.
- parser.buffer = parser.buffer[:cap(parser.buffer)]
-
- // Fill the buffer until it has enough characters.
- first := true
- for parser.unread < length {
-
- // Fill the raw buffer if necessary.
- if !first || parser.raw_buffer_pos == len(parser.raw_buffer) {
- if !yaml_parser_update_raw_buffer(parser) {
- parser.buffer = parser.buffer[:buffer_len]
- return false
- }
- }
- first = false
-
- // Decode the raw buffer.
- inner:
- for parser.raw_buffer_pos != len(parser.raw_buffer) {
- var value rune
- var width int
-
- raw_unread := len(parser.raw_buffer) - parser.raw_buffer_pos
-
- // 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[parser.raw_buffer_pos]
- switch {
- case octet&0x80 == 0x00:
- width = 1
- case octet&0xE0 == 0xC0:
- width = 2
- case octet&0xF0 == 0xE0:
- width = 3
- case octet&0xF8 == 0xF0:
- width = 4
- default:
- // The leading octet is invalid.
- return yaml_parser_set_reader_error(parser,
- "invalid leading UTF-8 octet",
- parser.offset, int(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)
- }
- break inner
- }
-
- // Decode the leading octet.
- switch {
- case octet&0x80 == 0x00:
- value = rune(octet & 0x7F)
- case octet&0xE0 == 0xC0:
- value = rune(octet & 0x1F)
- case octet&0xF0 == 0xE0:
- value = rune(octet & 0x0F)
- case octet&0xF8 == 0xF0:
- value = rune(octet & 0x07)
- default:
- value = 0
- }
-
- // Check and decode the trailing octets.
- for k := 1; k < width; k++ {
- octet = parser.raw_buffer[parser.raw_buffer_pos+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, int(octet))
- }
-
- // Decode the octet.
- value = (value << 6) + rune(octet&0x3F)
- }
-
- // Check the length of the sequence against the value.
- switch {
- case width == 1:
- case width == 2 && value >= 0x80:
- case width == 3 && value >= 0x800:
- case width == 4 && value >= 0x10000:
- default:
- 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, int(value))
- }
-
- case yaml_UTF16LE_ENCODING, yaml_UTF16BE_ENCODING:
- var low, high int
- if parser.encoding == yaml_UTF16LE_ENCODING {
- low, high = 0, 1
- } else {
- low, high = 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)
- }
- break inner
- }
-
- // Get the character.
- value = rune(parser.raw_buffer[parser.raw_buffer_pos+low]) +
- (rune(parser.raw_buffer[parser.raw_buffer_pos+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, int(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)
- }
- break inner
- }
-
- // Get the next character.
- value2 := rune(parser.raw_buffer[parser.raw_buffer_pos+low+2]) +
- (rune(parser.raw_buffer[parser.raw_buffer_pos+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, int(value2))
- }
-
- // Generate the value of the surrogate pair.
- value = 0x10000 + ((value & 0x3FF) << 10) + (value2 & 0x3FF)
- } else {
- width = 2
- }
-
- default:
- panic("impossible")
- }
-
- // 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)
- switch {
- case value == 0x09:
- case value == 0x0A:
- case value == 0x0D:
- case value >= 0x20 && value <= 0x7E:
- case value == 0x85:
- case value >= 0xA0 && value <= 0xD7FF:
- case value >= 0xE000 && value <= 0xFFFD:
- case value >= 0x10000 && value <= 0x10FFFF:
- default:
- return yaml_parser_set_reader_error(parser,
- "control characters are not allowed",
- parser.offset, int(value))
- }
-
- // Move the raw pointers.
- parser.raw_buffer_pos += width
- parser.offset += width
-
- // Finally put the character into the buffer.
- if value <= 0x7F {
- // 0000 0000-0000 007F . 0xxxxxxx
- parser.buffer[buffer_len+0] = byte(value)
- buffer_len += 1
- } else if value <= 0x7FF {
- // 0000 0080-0000 07FF . 110xxxxx 10xxxxxx
- parser.buffer[buffer_len+0] = byte(0xC0 + (value >> 6))
- parser.buffer[buffer_len+1] = byte(0x80 + (value & 0x3F))
- buffer_len += 2
- } else if value <= 0xFFFF {
- // 0000 0800-0000 FFFF . 1110xxxx 10xxxxxx 10xxxxxx
- parser.buffer[buffer_len+0] = byte(0xE0 + (value >> 12))
- parser.buffer[buffer_len+1] = byte(0x80 + ((value >> 6) & 0x3F))
- parser.buffer[buffer_len+2] = byte(0x80 + (value & 0x3F))
- buffer_len += 3
- } else {
- // 0001 0000-0010 FFFF . 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
- parser.buffer[buffer_len+0] = byte(0xF0 + (value >> 18))
- parser.buffer[buffer_len+1] = byte(0x80 + ((value >> 12) & 0x3F))
- parser.buffer[buffer_len+2] = byte(0x80 + ((value >> 6) & 0x3F))
- parser.buffer[buffer_len+3] = byte(0x80 + (value & 0x3F))
- buffer_len += 4
- }
-
- parser.unread++
- }
-
- // On EOF, put NUL into the buffer and return.
- if parser.eof {
- parser.buffer[buffer_len] = 0
- buffer_len++
- parser.unread++
- break
- }
- }
- // [Go] Read the documentation of this function above. To return true,
- // we need to have the given length in the buffer. Not doing that means
- // every single check that calls this function to make sure the buffer
- // has a given length is Go) panicking; or C) accessing invalid memory.
- // This happens here due to the EOF above breaking early.
- for buffer_len < length {
- parser.buffer[buffer_len] = 0
- buffer_len++
- }
- parser.buffer = parser.buffer[:buffer_len]
- return true
- }
|