Vendor integration dependencies.

integration/vendor/github.com/cloudfoundry-incubator/candiedyaml/reader.go

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+/*
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package candiedyaml
+
+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. */
+	raw := parser.raw_buffer
+	pos := parser.raw_buffer_pos
+	remaining := len(raw) - pos
+	if remaining >= 2 &&
+		raw[pos] == BOM_UTF16LE[0] && raw[pos+1] == BOM_UTF16LE[1] {
+		parser.encoding = yaml_UTF16LE_ENCODING
+		parser.raw_buffer_pos += 2
+		parser.offset += 2
+	} else if remaining >= 2 &&
+		raw[pos] == BOM_UTF16BE[0] && raw[pos+1] == BOM_UTF16BE[1] {
+		parser.encoding = yaml_UTF16BE_ENCODING
+		parser.raw_buffer_pos += 2
+		parser.offset += 2
+	} else if remaining >= 3 &&
+		raw[pos] == BOM_UTF8[0] && raw[pos+1] == BOM_UTF8[1] && raw[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 1 on success, 0 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 {
+	/* Read handler must be set. */
+	if parser.read_handler == nil {
+		panic("read handler must be set")
+	}
+
+	/* 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) {
+		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_end := len(parser.buffer)
+	if 0 < parser.buffer_pos &&
+		parser.buffer_pos < buffer_end {
+		copy(parser.buffer, parser.buffer[parser.buffer_pos:])
+		buffer_end -= parser.buffer_pos
+		parser.buffer_pos = 0
+	} else if parser.buffer_pos == buffer_end {
+		buffer_end = 0
+		parser.buffer_pos = 0
+	}
+
+	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_end]
+				return false
+			}
+		}
+		first = false
+
+		/* Decode the raw buffer. */
+		for parser.raw_buffer_pos != len(parser.raw_buffer) {
+			var value rune
+			var w int
+
+			raw_unread := len(parser.raw_buffer) - parser.raw_buffer_pos
+			incomplete := false
+
+			/* 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]
+				w = width(octet)
+
+				/* Check if the leading octet is valid. */
+
+				if w == 0 {
+					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 w > raw_unread {
+					if parser.eof {
+						return yaml_parser_set_reader_error(parser,
+							"incomplete UTF-8 octet sequence",
+							parser.offset, -1)
+					}
+					incomplete = true
+					break
+				}
+
+				/* 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 < w; 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 w == 1:
+				case w == 2 && value >= 0x80:
+				case w == 3 && value >= 0x800:
+				case w == 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 {
+					high, low = 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 = true
+					break
+				}
+
+				/* 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 {
+
+					w = 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 = true
+						break
+					}
+
+					/* 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 {
+					w = 2
+				}
+
+				break
+
+			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
+}