summaryrefslogtreecommitdiff
path: root/vendor/gopkg.in/yaml.v3/readerc.go
blob: b7de0a89c462af605f889bc46ce165e5d4238add (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
// 
// Copyright (c) 2011-2019 Canonical Ltd
// Copyright (c) 2006-2010 Kirill Simonov
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
// of the Software, and to permit persons to whom the Software is furnished to do
// so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

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
}