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// |
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// Copyright (c) 2011-2019 Canonical Ltd |
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// Copyright (c) 2006-2010 Kirill Simonov |
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// |
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// Permission is hereby granted, free of charge, to any person obtaining a copy of |
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// this software and associated documentation files (the "Software"), to deal in |
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// the Software without restriction, including without limitation the rights to |
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// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies |
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// of the Software, and to permit persons to whom the Software is furnished to do |
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// so, subject to the following conditions: |
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// |
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// The above copyright notice and this permission notice shall be included in all |
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// copies or substantial portions of the Software. |
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// |
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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// SOFTWARE. |
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|
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package yaml |
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|
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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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func yaml_parser_set_reader_error(parser *yaml_parser_t, problem string, 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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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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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 && 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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|
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// Determine the encoding. |
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buf := parser.raw_buffer |
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pos := parser.raw_buffer_pos |
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avail := len(buf) - pos |
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if avail >= 2 && buf[pos] == bom_UTF16LE[0] && buf[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 avail >= 2 && buf[pos] == bom_UTF16BE[0] && buf[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 avail >= 3 && buf[pos] == bom_UTF8[0] && buf[pos+1] == bom_UTF8[1] && buf[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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func yaml_parser_update_raw_buffer(parser *yaml_parser_t) bool { |
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size_read := 0 |
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|
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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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|
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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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|
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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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|
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// Call the read handler to fill the buffer. |
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size_read, err := parser.read_handler(parser, 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(), 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 true on success, false 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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func yaml_parser_update_buffer(parser *yaml_parser_t, length int) bool { |
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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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|
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// [Go] This function was changed to guarantee the requested length size at EOF. |
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// The fact we need to do this is pretty awful, but the description above implies |
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// for that to be the case, and there are tests |
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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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// [Go] ACTUALLY! Read the documentation of this function above. |
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// This is just broken. To return true, we need to have the |
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// given length in the buffer. Not doing that means every single |
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// check that calls this function to make sure the buffer has a |
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// given length is Go) panicking; or C) accessing invalid memory. |
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//return true |
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} |
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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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|
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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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|
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// Move the unread characters to the beginning of the buffer. |
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buffer_len := len(parser.buffer) |
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if parser.buffer_pos > 0 && parser.buffer_pos < buffer_len { |
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copy(parser.buffer, parser.buffer[parser.buffer_pos:]) |
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buffer_len -= parser.buffer_pos |
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parser.buffer_pos = 0 |
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} else if parser.buffer_pos == buffer_len { |
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buffer_len = 0 |
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parser.buffer_pos = 0 |
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} |
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|
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// Open the whole buffer for writing, and cut it before returning. |
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parser.buffer = parser.buffer[:cap(parser.buffer)] |
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|
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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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|
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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_len] |
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return false |
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} |
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} |
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first = false |
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|
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// Decode the raw buffer. |
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inner: |
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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 width int |
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|
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raw_unread := len(parser.raw_buffer) - parser.raw_buffer_pos |
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|
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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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// 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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switch { |
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case octet&0x80 == 0x00: |
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width = 1 |
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case octet&0xE0 == 0xC0: |
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width = 2 |
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case octet&0xF0 == 0xE0: |
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width = 3 |
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case octet&0xF8 == 0xF0: |
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width = 4 |
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default: |
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// The leading octet is invalid. |
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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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|
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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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break inner |
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} |
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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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|
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// Check and decode the trailing octets. |
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for k := 1; k < width; k++ { |
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octet = parser.raw_buffer[parser.raw_buffer_pos+k] |
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|
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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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|
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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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|
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// Check the length of the sequence against the value. |
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switch { |
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case width == 1: |
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case width == 2 && value >= 0x80: |
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case width == 3 && value >= 0x800: |
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case width == 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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|
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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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|
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case yaml_UTF16LE_ENCODING, 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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low, high = 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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break inner |
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} |
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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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|
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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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|
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// Check for a high surrogate area. |
| 330 |
if value&0xFC00 == 0xD800 { |
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width = 4 |
| 332 |
|
| 333 |
// Check for incomplete surrogate pair. |
| 334 |
if raw_unread < 4 { |
| 335 |
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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break inner |
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} |
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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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|
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// Check for a low surrogate area. |
| 348 |
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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} |
| 353 |
|
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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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width = 2 |
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} |
| 359 |
|
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default: |
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panic("impossible") |
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} |
| 363 |
|
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// Check if the character is in the allowed range: |
| 365 |
// #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) |
| 368 |
switch { |
| 369 |
case value == 0x09: |
| 370 |
case value == 0x0A: |
| 371 |
case value == 0x0D: |
| 372 |
case value >= 0x20 && value <= 0x7E: |
| 373 |
case value == 0x85: |
| 374 |
case value >= 0xA0 && value <= 0xD7FF: |
| 375 |
case value >= 0xE000 && value <= 0xFFFD: |
| 376 |
case value >= 0x10000 && value <= 0x10FFFF: |
| 377 |
default: |
| 378 |
return yaml_parser_set_reader_error(parser, |
| 379 |
"control characters are not allowed", |
| 380 |
parser.offset, int(value)) |
| 381 |
} |
| 382 |
|
| 383 |
// Move the raw pointers. |
| 384 |
parser.raw_buffer_pos += width |
| 385 |
parser.offset += width |
| 386 |
|
| 387 |
// Finally put the character into the buffer. |
| 388 |
if value <= 0x7F { |
| 389 |
// 0000 0000-0000 007F . 0xxxxxxx |
| 390 |
parser.buffer[buffer_len+0] = byte(value) |
| 391 |
buffer_len += 1 |
| 392 |
} else if value <= 0x7FF { |
| 393 |
// 0000 0080-0000 07FF . 110xxxxx 10xxxxxx |
| 394 |
parser.buffer[buffer_len+0] = byte(0xC0 + (value >> 6)) |
| 395 |
parser.buffer[buffer_len+1] = byte(0x80 + (value & 0x3F)) |
| 396 |
buffer_len += 2 |
| 397 |
} else if value <= 0xFFFF { |
| 398 |
// 0000 0800-0000 FFFF . 1110xxxx 10xxxxxx 10xxxxxx |
| 399 |
parser.buffer[buffer_len+0] = byte(0xE0 + (value >> 12)) |
| 400 |
parser.buffer[buffer_len+1] = byte(0x80 + ((value >> 6) & 0x3F)) |
| 401 |
parser.buffer[buffer_len+2] = byte(0x80 + (value & 0x3F)) |
| 402 |
buffer_len += 3 |
| 403 |
} else { |
| 404 |
// 0001 0000-0010 FFFF . 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx |
| 405 |
parser.buffer[buffer_len+0] = byte(0xF0 + (value >> 18)) |
| 406 |
parser.buffer[buffer_len+1] = byte(0x80 + ((value >> 12) & 0x3F)) |
| 407 |
parser.buffer[buffer_len+2] = byte(0x80 + ((value >> 6) & 0x3F)) |
| 408 |
parser.buffer[buffer_len+3] = byte(0x80 + (value & 0x3F)) |
| 409 |
buffer_len += 4 |
| 410 |
} |
| 411 |
|
| 412 |
parser.unread++ |
| 413 |
} |
| 414 |
|
| 415 |
// On EOF, put NUL into the buffer and return. |
| 416 |
if parser.eof { |
| 417 |
parser.buffer[buffer_len] = 0 |
| 418 |
buffer_len++ |
| 419 |
parser.unread++ |
| 420 |
break |
| 421 |
} |
| 422 |
} |
| 423 |
// [Go] Read the documentation of this function above. To return true, |
| 424 |
// we need to have the given length in the buffer. Not doing that means |
| 425 |
// every single check that calls this function to make sure the buffer |
| 426 |
// has a given length is Go) panicking; or C) accessing invalid memory. |
| 427 |
// This happens here due to the EOF above breaking early. |
| 428 |
for buffer_len < length { |
| 429 |
parser.buffer[buffer_len] = 0 |
| 430 |
buffer_len++ |
| 431 |
} |
| 432 |
parser.buffer = parser.buffer[:buffer_len] |
| 433 |
return true |
| 434 |
} |
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