466 lines
12 KiB
Go
466 lines
12 KiB
Go
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/*
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package candiedyaml
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import (
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"io"
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)
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/*
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* Set the reader error and return 0.
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*/
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func yaml_parser_set_reader_error(parser *yaml_parser_t, problem string,
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offset int, value int) bool {
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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 false
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}
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/*
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* Byte order marks.
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*/
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const (
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BOM_UTF8 = "\xef\xbb\xbf"
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BOM_UTF16LE = "\xff\xfe"
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BOM_UTF16BE = "\xfe\xff"
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)
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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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func yaml_parser_determine_encoding(parser *yaml_parser_t) bool {
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/* Ensure that we had enough bytes in the raw buffer. */
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for !parser.eof &&
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len(parser.raw_buffer)-parser.raw_buffer_pos < 3 {
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if !yaml_parser_update_raw_buffer(parser) {
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return false
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}
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}
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/* Determine the encoding. */
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raw := parser.raw_buffer
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pos := parser.raw_buffer_pos
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remaining := len(raw) - pos
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if remaining >= 2 &&
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raw[pos] == BOM_UTF16LE[0] && raw[pos+1] == BOM_UTF16LE[1] {
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parser.encoding = yaml_UTF16LE_ENCODING
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parser.raw_buffer_pos += 2
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parser.offset += 2
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} else if remaining >= 2 &&
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raw[pos] == BOM_UTF16BE[0] && raw[pos+1] == BOM_UTF16BE[1] {
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parser.encoding = yaml_UTF16BE_ENCODING
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parser.raw_buffer_pos += 2
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parser.offset += 2
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} else if remaining >= 3 &&
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raw[pos] == BOM_UTF8[0] && raw[pos+1] == BOM_UTF8[1] && raw[pos+2] == BOM_UTF8[2] {
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parser.encoding = yaml_UTF8_ENCODING
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parser.raw_buffer_pos += 3
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parser.offset += 3
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} else {
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parser.encoding = yaml_UTF8_ENCODING
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}
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return true
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}
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/*
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* Update the raw buffer.
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*/
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func yaml_parser_update_raw_buffer(parser *yaml_parser_t) bool {
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size_read := 0
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/* Return if the raw buffer is full. */
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if parser.raw_buffer_pos == 0 && len(parser.raw_buffer) == cap(parser.raw_buffer) {
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return true
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}
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/* Return on EOF. */
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if parser.eof {
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return true
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}
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/* Move the remaining bytes in the raw buffer to the beginning. */
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if parser.raw_buffer_pos > 0 && parser.raw_buffer_pos < len(parser.raw_buffer) {
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copy(parser.raw_buffer, parser.raw_buffer[parser.raw_buffer_pos:])
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}
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parser.raw_buffer = parser.raw_buffer[:len(parser.raw_buffer)-parser.raw_buffer_pos]
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parser.raw_buffer_pos = 0
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/* Call the read handler to fill the buffer. */
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size_read, err := parser.read_handler(parser,
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parser.raw_buffer[len(parser.raw_buffer):cap(parser.raw_buffer)])
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parser.raw_buffer = parser.raw_buffer[:len(parser.raw_buffer)+size_read]
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if err == io.EOF {
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parser.eof = true
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} else if err != nil {
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return yaml_parser_set_reader_error(parser, "input error: "+err.Error(),
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parser.offset, -1)
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}
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return true
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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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func yaml_parser_update_buffer(parser *yaml_parser_t, length int) bool {
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/* Read handler must be set. */
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if parser.read_handler == nil {
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panic("read handler must be set")
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}
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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_pos == len(parser.raw_buffer) {
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return true
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}
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/* Return if the buffer contains enough characters. */
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if parser.unread >= length {
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return true
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}
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/* Determine the input encoding if it is not known yet. */
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if parser.encoding == yaml_ANY_ENCODING {
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if !yaml_parser_determine_encoding(parser) {
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return false
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}
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}
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/* Move the unread characters to the beginning of the buffer. */
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buffer_end := len(parser.buffer)
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if 0 < parser.buffer_pos &&
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parser.buffer_pos < buffer_end {
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copy(parser.buffer, parser.buffer[parser.buffer_pos:])
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buffer_end -= parser.buffer_pos
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parser.buffer_pos = 0
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} else if parser.buffer_pos == buffer_end {
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buffer_end = 0
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parser.buffer_pos = 0
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}
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parser.buffer = parser.buffer[:cap(parser.buffer)]
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/* Fill the buffer until it has enough characters. */
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first := true
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for parser.unread < length {
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/* Fill the raw buffer if necessary. */
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if !first || parser.raw_buffer_pos == len(parser.raw_buffer) {
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if !yaml_parser_update_raw_buffer(parser) {
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parser.buffer = parser.buffer[:buffer_end]
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return false
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}
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}
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first = false
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/* Decode the raw buffer. */
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for parser.raw_buffer_pos != len(parser.raw_buffer) {
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var value rune
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var w int
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raw_unread := len(parser.raw_buffer) - parser.raw_buffer_pos
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incomplete := false
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/* Decode the next character. */
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switch parser.encoding {
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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[parser.raw_buffer_pos]
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w = width(octet)
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/* Check if the leading octet is valid. */
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if w == 0 {
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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, int(octet))
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}
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/* Check if the raw buffer contains an incomplete character. */
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if w > 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 = true
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break
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}
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/* Decode the leading octet. */
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switch {
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case octet&0x80 == 0x00:
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value = rune(octet & 0x7F)
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case octet&0xE0 == 0xC0:
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value = rune(octet & 0x1F)
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case octet&0xF0 == 0xE0:
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value = rune(octet & 0x0F)
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case octet&0xF8 == 0xF0:
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value = rune(octet & 0x07)
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default:
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value = 0
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}
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/* Check and decode the trailing octets. */
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for k := 1; k < w; k++ {
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octet = parser.raw_buffer[parser.raw_buffer_pos+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, int(octet))
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}
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/* Decode the octet. */
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value = (value << 6) + rune(octet&0x3F)
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}
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/* Check the length of the sequence against the value. */
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switch {
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case w == 1:
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case w == 2 && value >= 0x80:
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case w == 3 && value >= 0x800:
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case w == 4 && value >= 0x10000:
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default:
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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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}
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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, int(value))
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}
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case yaml_UTF16LE_ENCODING,
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yaml_UTF16BE_ENCODING:
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var low, high int
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if parser.encoding == yaml_UTF16LE_ENCODING {
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low, high = 0, 1
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} else {
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high, low = 1, 0
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}
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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 = true
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break
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}
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/* Get the character. */
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value = rune(parser.raw_buffer[parser.raw_buffer_pos+low]) +
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(rune(parser.raw_buffer[parser.raw_buffer_pos+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, int(value))
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}
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/* Check for a high surrogate area. */
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if (value & 0xFC00) == 0xD800 {
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w = 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 = true
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break
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}
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/* Get the next character. */
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value2 := rune(parser.raw_buffer[parser.raw_buffer_pos+low+2]) +
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(rune(parser.raw_buffer[parser.raw_buffer_pos+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, int(value2))
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}
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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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} else {
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w = 2
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}
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break
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|
||
|
|
default:
|
||
|
|
panic("Impossible") /* 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, int(value))
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Move the raw pointers. */
|
||
|
|
|
||
|
|
parser.raw_buffer_pos += w
|
||
|
|
parser.offset += w
|
||
|
|
|
||
|
|
/* Finally put the character into the buffer. */
|
||
|
|
|
||
|
|
/* 0000 0000-0000 007F . 0xxxxxxx */
|
||
|
|
if value <= 0x7F {
|
||
|
|
parser.buffer[buffer_end] = byte(value)
|
||
|
|
} else if value <= 0x7FF {
|
||
|
|
/* 0000 0080-0000 07FF . 110xxxxx 10xxxxxx */
|
||
|
|
parser.buffer[buffer_end] = byte(0xC0 + (value >> 6))
|
||
|
|
parser.buffer[buffer_end+1] = byte(0x80 + (value & 0x3F))
|
||
|
|
} else if value <= 0xFFFF {
|
||
|
|
/* 0000 0800-0000 FFFF . 1110xxxx 10xxxxxx 10xxxxxx */
|
||
|
|
parser.buffer[buffer_end] = byte(0xE0 + (value >> 12))
|
||
|
|
parser.buffer[buffer_end+1] = byte(0x80 + ((value >> 6) & 0x3F))
|
||
|
|
parser.buffer[buffer_end+2] = byte(0x80 + (value & 0x3F))
|
||
|
|
} else {
|
||
|
|
/* 0001 0000-0010 FFFF . 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
|
||
|
|
parser.buffer[buffer_end] = byte(0xF0 + (value >> 18))
|
||
|
|
parser.buffer[buffer_end+1] = byte(0x80 + ((value >> 12) & 0x3F))
|
||
|
|
parser.buffer[buffer_end+2] = byte(0x80 + ((value >> 6) & 0x3F))
|
||
|
|
parser.buffer[buffer_end+3] = byte(0x80 + (value & 0x3F))
|
||
|
|
}
|
||
|
|
|
||
|
|
buffer_end += w
|
||
|
|
parser.unread++
|
||
|
|
}
|
||
|
|
|
||
|
|
/* On EOF, put NUL into the buffer and return. */
|
||
|
|
|
||
|
|
if parser.eof {
|
||
|
|
parser.buffer[buffer_end] = 0
|
||
|
|
buffer_end++
|
||
|
|
parser.buffer = parser.buffer[:buffer_end]
|
||
|
|
parser.unread++
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
parser.buffer = parser.buffer[:buffer_end]
|
||
|
|
return true
|
||
|
|
}
|