1
2/*
3 * Introduction
4 * ************
5 *
6 * The following notes assume that you are familiar with the YAML specification
7 * (http://yaml.org/spec/cvs/current.html).  We mostly follow it, although in
8 * some cases we are less restrictive that it requires.
9 *
10 * The process of transforming a YAML stream into a sequence of events is
11 * divided on two steps: Scanning and Parsing.
12 *
13 * The Scanner transforms the input stream into a sequence of tokens, while the
14 * parser transform the sequence of tokens produced by the Scanner into a
15 * sequence of parsing events.
16 *
17 * The Scanner is rather clever and complicated. The Parser, on the contrary,
18 * is a straightforward implementation of a recursive-descendant parser (or,
19 * LL(1) parser, as it is usually called).
20 *
21 * Actually there are two issues of Scanning that might be called "clever", the
22 * rest is quite straightforward.  The issues are "block collection start" and
23 * "simple keys".  Both issues are explained below in details.
24 *
25 * Here the Scanning step is explained and implemented.  We start with the list
26 * of all the tokens produced by the Scanner together with short descriptions.
27 *
28 * Now, tokens:
29 *
30 *      STREAM-START(encoding)          # The stream start.
31 *      STREAM-END                      # The stream end.
32 *      VERSION-DIRECTIVE(major,minor)  # The '%YAML' directive.
33 *      TAG-DIRECTIVE(handle,prefix)    # The '%TAG' directive.
34 *      DOCUMENT-START                  # '---'
35 *      DOCUMENT-END                    # '...'
36 *      BLOCK-SEQUENCE-START            # Indentation increase denoting a block
37 *      BLOCK-MAPPING-START             # sequence or a block mapping.
38 *      BLOCK-END                       # Indentation decrease.
39 *      FLOW-SEQUENCE-START             # '['
40 *      FLOW-SEQUENCE-END               # ']'
41 *      BLOCK-SEQUENCE-START            # '{'
42 *      BLOCK-SEQUENCE-END              # '}'
43 *      BLOCK-ENTRY                     # '-'
44 *      FLOW-ENTRY                      # ','
45 *      KEY                             # '?' or nothing (simple keys).
46 *      VALUE                           # ':'
47 *      ALIAS(anchor)                   # '*anchor'
48 *      ANCHOR(anchor)                  # '&anchor'
49 *      TAG(handle,suffix)              # '!handle!suffix'
50 *      SCALAR(value,style)             # A scalar.
51 *
52 * The following two tokens are "virtual" tokens denoting the beginning and the
53 * end of the stream:
54 *
55 *      STREAM-START(encoding)
56 *      STREAM-END
57 *
58 * We pass the information about the input stream encoding with the
59 * STREAM-START token.
60 *
61 * The next two tokens are responsible for tags:
62 *
63 *      VERSION-DIRECTIVE(major,minor)
64 *      TAG-DIRECTIVE(handle,prefix)
65 *
66 * Example:
67 *
68 *      %YAML   1.1
69 *      %TAG    !   !foo
70 *      %TAG    !yaml!  tag:yaml.org,2002:
71 *      ---
72 *
73 * The correspoding sequence of tokens:
74 *
75 *      STREAM-START(utf-8)
76 *      VERSION-DIRECTIVE(1,1)
77 *      TAG-DIRECTIVE("!","!foo")
78 *      TAG-DIRECTIVE("!yaml","tag:yaml.org,2002:")
79 *      DOCUMENT-START
80 *      STREAM-END
81 *
82 * Note that the VERSION-DIRECTIVE and TAG-DIRECTIVE tokens occupy a whole
83 * line.
84 *
85 * The document start and end indicators are represented by:
86 *
87 *      DOCUMENT-START
88 *      DOCUMENT-END
89 *
90 * Note that if a YAML stream contains an implicit document (without '---'
91 * and '...' indicators), no DOCUMENT-START and DOCUMENT-END tokens will be
92 * produced.
93 *
94 * In the following examples, we present whole documents together with the
95 * produced tokens.
96 *
97 *      1. An implicit document:
98 *
99 *          'a scalar'
100 *
101 *      Tokens:
102 *
103 *          STREAM-START(utf-8)
104 *          SCALAR("a scalar",single-quoted)
105 *          STREAM-END
106 *
107 *      2. An explicit document:
108 *
109 *          ---
110 *          'a scalar'
111 *          ...
112 *
113 *      Tokens:
114 *
115 *          STREAM-START(utf-8)
116 *          DOCUMENT-START
117 *          SCALAR("a scalar",single-quoted)
118 *          DOCUMENT-END
119 *          STREAM-END
120 *
121 *      3. Several documents in a stream:
122 *
123 *          'a scalar'
124 *          ---
125 *          'another scalar'
126 *          ---
127 *          'yet another scalar'
128 *
129 *      Tokens:
130 *
131 *          STREAM-START(utf-8)
132 *          SCALAR("a scalar",single-quoted)
133 *          DOCUMENT-START
134 *          SCALAR("another scalar",single-quoted)
135 *          DOCUMENT-START
136 *          SCALAR("yet another scalar",single-quoted)
137 *          STREAM-END
138 *
139 * We have already introduced the SCALAR token above.  The following tokens are
140 * used to describe aliases, anchors, tag, and scalars:
141 *
142 *      ALIAS(anchor)
143 *      ANCHOR(anchor)
144 *      TAG(handle,suffix)
145 *      SCALAR(value,style)
146 *
147 * The following series of examples illustrate the usage of these tokens:
148 *
149 *      1. A recursive sequence:
150 *
151 *          &A [ *A ]
152 *
153 *      Tokens:
154 *
155 *          STREAM-START(utf-8)
156 *          ANCHOR("A")
157 *          FLOW-SEQUENCE-START
158 *          ALIAS("A")
159 *          FLOW-SEQUENCE-END
160 *          STREAM-END
161 *
162 *      2. A tagged scalar:
163 *
164 *          !!float "3.14"  # A good approximation.
165 *
166 *      Tokens:
167 *
168 *          STREAM-START(utf-8)
169 *          TAG("!!","float")
170 *          SCALAR("3.14",double-quoted)
171 *          STREAM-END
172 *
173 *      3. Various scalar styles:
174 *
175 *          --- # Implicit empty plain scalars do not produce tokens.
176 *          --- a plain scalar
177 *          --- 'a single-quoted scalar'
178 *          --- "a double-quoted scalar"
179 *          --- |-
180 *            a literal scalar
181 *          --- >-
182 *            a folded
183 *            scalar
184 *
185 *      Tokens:
186 *
187 *          STREAM-START(utf-8)
188 *          DOCUMENT-START
189 *          DOCUMENT-START
190 *          SCALAR("a plain scalar",plain)
191 *          DOCUMENT-START
192 *          SCALAR("a single-quoted scalar",single-quoted)
193 *          DOCUMENT-START
194 *          SCALAR("a double-quoted scalar",double-quoted)
195 *          DOCUMENT-START
196 *          SCALAR("a literal scalar",literal)
197 *          DOCUMENT-START
198 *          SCALAR("a folded scalar",folded)
199 *          STREAM-END
200 *
201 * Now it's time to review collection-related tokens. We will start with
202 * flow collections:
203 *
204 *      FLOW-SEQUENCE-START
205 *      FLOW-SEQUENCE-END
206 *      FLOW-MAPPING-START
207 *      FLOW-MAPPING-END
208 *      FLOW-ENTRY
209 *      KEY
210 *      VALUE
211 *
212 * The tokens FLOW-SEQUENCE-START, FLOW-SEQUENCE-END, FLOW-MAPPING-START, and
213 * FLOW-MAPPING-END represent the indicators '[', ']', '{', and '}'
214 * correspondingly.  FLOW-ENTRY represent the ',' indicator.  Finally the
215 * indicators '?' and ':', which are used for denoting mapping keys and values,
216 * are represented by the KEY and VALUE tokens.
217 *
218 * The following examples show flow collections:
219 *
220 *      1. A flow sequence:
221 *
222 *          [item 1, item 2, item 3]
223 *
224 *      Tokens:
225 *
226 *          STREAM-START(utf-8)
227 *          FLOW-SEQUENCE-START
228 *          SCALAR("item 1",plain)
229 *          FLOW-ENTRY
230 *          SCALAR("item 2",plain)
231 *          FLOW-ENTRY
232 *          SCALAR("item 3",plain)
233 *          FLOW-SEQUENCE-END
234 *          STREAM-END
235 *
236 *      2. A flow mapping:
237 *
238 *          {
239 *              a simple key: a value,  # Note that the KEY token is produced.
240 *              ? a complex key: another value,
241 *          }
242 *
243 *      Tokens:
244 *
245 *          STREAM-START(utf-8)
246 *          FLOW-MAPPING-START
247 *          KEY
248 *          SCALAR("a simple key",plain)
249 *          VALUE
250 *          SCALAR("a value",plain)
251 *          FLOW-ENTRY
252 *          KEY
253 *          SCALAR("a complex key",plain)
254 *          VALUE
255 *          SCALAR("another value",plain)
256 *          FLOW-ENTRY
257 *          FLOW-MAPPING-END
258 *          STREAM-END
259 *
260 * A simple key is a key which is not denoted by the '?' indicator.  Note that
261 * the Scanner still produce the KEY token whenever it encounters a simple key.
262 *
263 * For scanning block collections, the following tokens are used (note that we
264 * repeat KEY and VALUE here):
265 *
266 *      BLOCK-SEQUENCE-START
267 *      BLOCK-MAPPING-START
268 *      BLOCK-END
269 *      BLOCK-ENTRY
270 *      KEY
271 *      VALUE
272 *
273 * The tokens BLOCK-SEQUENCE-START and BLOCK-MAPPING-START denote indentation
274 * increase that precedes a block collection (cf. the INDENT token in Python).
275 * The token BLOCK-END denote indentation decrease that ends a block collection
276 * (cf. the DEDENT token in Python).  However YAML has some syntax pecularities
277 * that makes detections of these tokens more complex.
278 *
279 * The tokens BLOCK-ENTRY, KEY, and VALUE are used to represent the indicators
280 * '-', '?', and ':' correspondingly.
281 *
282 * The following examples show how the tokens BLOCK-SEQUENCE-START,
283 * BLOCK-MAPPING-START, and BLOCK-END are emitted by the Scanner:
284 *
285 *      1. Block sequences:
286 *
287 *          - item 1
288 *          - item 2
289 *          -
290 *            - item 3.1
291 *            - item 3.2
292 *          -
293 *            key 1: value 1
294 *            key 2: value 2
295 *
296 *      Tokens:
297 *
298 *          STREAM-START(utf-8)
299 *          BLOCK-SEQUENCE-START
300 *          BLOCK-ENTRY
301 *          SCALAR("item 1",plain)
302 *          BLOCK-ENTRY
303 *          SCALAR("item 2",plain)
304 *          BLOCK-ENTRY
305 *          BLOCK-SEQUENCE-START
306 *          BLOCK-ENTRY
307 *          SCALAR("item 3.1",plain)
308 *          BLOCK-ENTRY
309 *          SCALAR("item 3.2",plain)
310 *          BLOCK-END
311 *          BLOCK-ENTRY
312 *          BLOCK-MAPPING-START
313 *          KEY
314 *          SCALAR("key 1",plain)
315 *          VALUE
316 *          SCALAR("value 1",plain)
317 *          KEY
318 *          SCALAR("key 2",plain)
319 *          VALUE
320 *          SCALAR("value 2",plain)
321 *          BLOCK-END
322 *          BLOCK-END
323 *          STREAM-END
324 *
325 *      2. Block mappings:
326 *
327 *          a simple key: a value   # The KEY token is produced here.
328 *          ? a complex key
329 *          : another value
330 *          a mapping:
331 *            key 1: value 1
332 *            key 2: value 2
333 *          a sequence:
334 *            - item 1
335 *            - item 2
336 *
337 *      Tokens:
338 *
339 *          STREAM-START(utf-8)
340 *          BLOCK-MAPPING-START
341 *          KEY
342 *          SCALAR("a simple key",plain)
343 *          VALUE
344 *          SCALAR("a value",plain)
345 *          KEY
346 *          SCALAR("a complex key",plain)
347 *          VALUE
348 *          SCALAR("another value",plain)
349 *          KEY
350 *          SCALAR("a mapping",plain)
351 *          BLOCK-MAPPING-START
352 *          KEY
353 *          SCALAR("key 1",plain)
354 *          VALUE
355 *          SCALAR("value 1",plain)
356 *          KEY
357 *          SCALAR("key 2",plain)
358 *          VALUE
359 *          SCALAR("value 2",plain)
360 *          BLOCK-END
361 *          KEY
362 *          SCALAR("a sequence",plain)
363 *          VALUE
364 *          BLOCK-SEQUENCE-START
365 *          BLOCK-ENTRY
366 *          SCALAR("item 1",plain)
367 *          BLOCK-ENTRY
368 *          SCALAR("item 2",plain)
369 *          BLOCK-END
370 *          BLOCK-END
371 *          STREAM-END
372 *
373 * YAML does not always require to start a new block collection from a new
374 * line.  If the current line contains only '-', '?', and ':' indicators, a new
375 * block collection may start at the current line.  The following examples
376 * illustrate this case:
377 *
378 *      1. Collections in a sequence:
379 *
380 *          - - item 1
381 *            - item 2
382 *          - key 1: value 1
383 *            key 2: value 2
384 *          - ? complex key
385 *            : complex value
386 *
387 *      Tokens:
388 *
389 *          STREAM-START(utf-8)
390 *          BLOCK-SEQUENCE-START
391 *          BLOCK-ENTRY
392 *          BLOCK-SEQUENCE-START
393 *          BLOCK-ENTRY
394 *          SCALAR("item 1",plain)
395 *          BLOCK-ENTRY
396 *          SCALAR("item 2",plain)
397 *          BLOCK-END
398 *          BLOCK-ENTRY
399 *          BLOCK-MAPPING-START
400 *          KEY
401 *          SCALAR("key 1",plain)
402 *          VALUE
403 *          SCALAR("value 1",plain)
404 *          KEY
405 *          SCALAR("key 2",plain)
406 *          VALUE
407 *          SCALAR("value 2",plain)
408 *          BLOCK-END
409 *          BLOCK-ENTRY
410 *          BLOCK-MAPPING-START
411 *          KEY
412 *          SCALAR("complex key")
413 *          VALUE
414 *          SCALAR("complex value")
415 *          BLOCK-END
416 *          BLOCK-END
417 *          STREAM-END
418 *
419 *      2. Collections in a mapping:
420 *
421 *          ? a sequence
422 *          : - item 1
423 *            - item 2
424 *          ? a mapping
425 *          : key 1: value 1
426 *            key 2: value 2
427 *
428 *      Tokens:
429 *
430 *          STREAM-START(utf-8)
431 *          BLOCK-MAPPING-START
432 *          KEY
433 *          SCALAR("a sequence",plain)
434 *          VALUE
435 *          BLOCK-SEQUENCE-START
436 *          BLOCK-ENTRY
437 *          SCALAR("item 1",plain)
438 *          BLOCK-ENTRY
439 *          SCALAR("item 2",plain)
440 *          BLOCK-END
441 *          KEY
442 *          SCALAR("a mapping",plain)
443 *          VALUE
444 *          BLOCK-MAPPING-START
445 *          KEY
446 *          SCALAR("key 1",plain)
447 *          VALUE
448 *          SCALAR("value 1",plain)
449 *          KEY
450 *          SCALAR("key 2",plain)
451 *          VALUE
452 *          SCALAR("value 2",plain)
453 *          BLOCK-END
454 *          BLOCK-END
455 *          STREAM-END
456 *
457 * YAML also permits non-indented sequences if they are included into a block
458 * mapping.  In this case, the token BLOCK-SEQUENCE-START is not produced:
459 *
460 *      key:
461 *      - item 1    # BLOCK-SEQUENCE-START is NOT produced here.
462 *      - item 2
463 *
464 * Tokens:
465 *
466 *      STREAM-START(utf-8)
467 *      BLOCK-MAPPING-START
468 *      KEY
469 *      SCALAR("key",plain)
470 *      VALUE
471 *      BLOCK-ENTRY
472 *      SCALAR("item 1",plain)
473 *      BLOCK-ENTRY
474 *      SCALAR("item 2",plain)
475 *      BLOCK-END
476 */
477
478#include "yaml_private.h"
479
480/*
481 * Ensure that the buffer contains the required number of characters.
482 * Return 1 on success, 0 on failure (reader error or memory error).
483 */
484
485#define CACHE(parser,length)                                                    \
486    (parser->unread >= (length)                                                 \
487        ? 1                                                                     \
488        : yaml_parser_update_buffer(parser, (length)))
489
490/*
491 * Advance the buffer pointer.
492 */
493
494#define SKIP(parser)                                                            \
495     (parser->mark.index ++,                                                    \
496      parser->mark.column ++,                                                   \
497      parser->unread --,                                                        \
498      parser->buffer.pointer += WIDTH(parser->buffer))
499
500#define SKIP_LINE(parser)                                                       \
501     (IS_CRLF(parser->buffer) ?                                                 \
502      (parser->mark.index += 2,                                                 \
503       parser->mark.column = 0,                                                 \
504       parser->mark.line ++,                                                    \
505       parser->unread -= 2,                                                     \
506       parser->buffer.pointer += 2) :                                           \
507      IS_BREAK(parser->buffer) ?                                                \
508      (parser->mark.index ++,                                                   \
509       parser->mark.column = 0,                                                 \
510       parser->mark.line ++,                                                    \
511       parser->unread --,                                                       \
512       parser->buffer.pointer += WIDTH(parser->buffer)) : 0)
513
514/*
515 * Copy a character to a string buffer and advance pointers.
516 */
517
518#define READ(parser,string)                                                     \
519     (STRING_EXTEND(parser,string) ?                                            \
520         (COPY(string,parser->buffer),                                          \
521          parser->mark.index ++,                                                \
522          parser->mark.column ++,                                               \
523          parser->unread --,                                                    \
524          1) : 0)
525
526/*
527 * Copy a line break character to a string buffer and advance pointers.
528 */
529
530#define READ_LINE(parser,string)                                                \
531    (STRING_EXTEND(parser,string) ?                                             \
532    (((CHECK_AT(parser->buffer,'\r',0)                                          \
533       && CHECK_AT(parser->buffer,'\n',1)) ?        /* CR LF -> LF */           \
534     (*((string).pointer++) = (yaml_char_t) '\n',                               \
535      parser->buffer.pointer += 2,                                              \
536      parser->mark.index += 2,                                                  \
537      parser->mark.column = 0,                                                  \
538      parser->mark.line ++,                                                     \
539      parser->unread -= 2) :                                                    \
540     (CHECK_AT(parser->buffer,'\r',0)                                           \
541      || CHECK_AT(parser->buffer,'\n',0)) ?         /* CR|LF -> LF */           \
542     (*((string).pointer++) = (yaml_char_t) '\n',                               \
543      parser->buffer.pointer ++,                                                \
544      parser->mark.index ++,                                                    \
545      parser->mark.column = 0,                                                  \
546      parser->mark.line ++,                                                     \
547      parser->unread --) :                                                      \
548     (CHECK_AT(parser->buffer,'\xC2',0)                                         \
549      && CHECK_AT(parser->buffer,'\x85',1)) ?       /* NEL -> LF */             \
550     (*((string).pointer++) = (yaml_char_t) '\n',                               \
551      parser->buffer.pointer += 2,                                              \
552      parser->mark.index ++,                                                    \
553      parser->mark.column = 0,                                                  \
554      parser->mark.line ++,                                                     \
555      parser->unread --) :                                                      \
556     (CHECK_AT(parser->buffer,'\xE2',0) &&                                      \
557      CHECK_AT(parser->buffer,'\x80',1) &&                                      \
558      (CHECK_AT(parser->buffer,'\xA8',2) ||                                     \
559       CHECK_AT(parser->buffer,'\xA9',2))) ?        /* LS|PS -> LS|PS */        \
560     (*((string).pointer++) = *(parser->buffer.pointer++),                      \
561      *((string).pointer++) = *(parser->buffer.pointer++),                      \
562      *((string).pointer++) = *(parser->buffer.pointer++),                      \
563      parser->mark.index ++,                                                    \
564      parser->mark.column = 0,                                                  \
565      parser->mark.line ++,                                                     \
566      parser->unread --) : 0),                                                  \
567    1) : 0)
568
569/*
570 * Public API declarations.
571 */
572
573YAML_DECLARE(int)
574yaml_parser_scan(yaml_parser_t *parser, yaml_token_t *token);
575
576/*
577 * Error handling.
578 */
579
580static int
581yaml_parser_set_scanner_error(yaml_parser_t *parser, const char *context,
582        yaml_mark_t context_mark, const char *problem);
583
584/*
585 * High-level token API.
586 */
587
588YAML_DECLARE(int)
589yaml_parser_fetch_more_tokens(yaml_parser_t *parser);
590
591static int
592yaml_parser_fetch_next_token(yaml_parser_t *parser);
593
594/*
595 * Potential simple keys.
596 */
597
598static int
599yaml_parser_stale_simple_keys(yaml_parser_t *parser);
600
601static int
602yaml_parser_save_simple_key(yaml_parser_t *parser);
603
604static int
605yaml_parser_remove_simple_key(yaml_parser_t *parser);
606
607static int
608yaml_parser_increase_flow_level(yaml_parser_t *parser);
609
610static int
611yaml_parser_decrease_flow_level(yaml_parser_t *parser);
612
613/*
614 * Indentation treatment.
615 */
616
617static int
618yaml_parser_roll_indent(yaml_parser_t *parser, ptrdiff_t column,
619        ptrdiff_t number, yaml_token_type_t type, yaml_mark_t mark);
620
621static int
622yaml_parser_unroll_indent(yaml_parser_t *parser, ptrdiff_t column);
623
624/*
625 * Token fetchers.
626 */
627
628static int
629yaml_parser_fetch_stream_start(yaml_parser_t *parser);
630
631static int
632yaml_parser_fetch_stream_end(yaml_parser_t *parser);
633
634static int
635yaml_parser_fetch_directive(yaml_parser_t *parser);
636
637static int
638yaml_parser_fetch_document_indicator(yaml_parser_t *parser,
639        yaml_token_type_t type);
640
641static int
642yaml_parser_fetch_flow_collection_start(yaml_parser_t *parser,
643        yaml_token_type_t type);
644
645static int
646yaml_parser_fetch_flow_collection_end(yaml_parser_t *parser,
647        yaml_token_type_t type);
648
649static int
650yaml_parser_fetch_flow_entry(yaml_parser_t *parser);
651
652static int
653yaml_parser_fetch_block_entry(yaml_parser_t *parser);
654
655static int
656yaml_parser_fetch_key(yaml_parser_t *parser);
657
658static int
659yaml_parser_fetch_value(yaml_parser_t *parser);
660
661static int
662yaml_parser_fetch_anchor(yaml_parser_t *parser, yaml_token_type_t type);
663
664static int
665yaml_parser_fetch_tag(yaml_parser_t *parser);
666
667static int
668yaml_parser_fetch_block_scalar(yaml_parser_t *parser, int literal);
669
670static int
671yaml_parser_fetch_flow_scalar(yaml_parser_t *parser, int single);
672
673static int
674yaml_parser_fetch_plain_scalar(yaml_parser_t *parser);
675
676/*
677 * Token scanners.
678 */
679
680static int
681yaml_parser_scan_to_next_token(yaml_parser_t *parser);
682
683static int
684yaml_parser_scan_directive(yaml_parser_t *parser, yaml_token_t *token);
685
686static int
687yaml_parser_scan_directive_name(yaml_parser_t *parser,
688        yaml_mark_t start_mark, yaml_char_t **name);
689
690static int
691yaml_parser_scan_version_directive_value(yaml_parser_t *parser,
692        yaml_mark_t start_mark, int *major, int *minor);
693
694static int
695yaml_parser_scan_version_directive_number(yaml_parser_t *parser,
696        yaml_mark_t start_mark, int *number);
697
698static int
699yaml_parser_scan_tag_directive_value(yaml_parser_t *parser,
700        yaml_mark_t mark, yaml_char_t **handle, yaml_char_t **prefix);
701
702static int
703yaml_parser_scan_anchor(yaml_parser_t *parser, yaml_token_t *token,
704        yaml_token_type_t type);
705
706static int
707yaml_parser_scan_tag(yaml_parser_t *parser, yaml_token_t *token);
708
709static int
710yaml_parser_scan_tag_handle(yaml_parser_t *parser, int directive,
711        yaml_mark_t start_mark, yaml_char_t **handle);
712
713static int
714yaml_parser_scan_tag_uri(yaml_parser_t *parser, int directive,
715        yaml_char_t *head, yaml_mark_t start_mark, yaml_char_t **uri);
716
717static int
718yaml_parser_scan_uri_escapes(yaml_parser_t *parser, int directive,
719        yaml_mark_t start_mark, yaml_string_t *string);
720
721static int
722yaml_parser_scan_block_scalar(yaml_parser_t *parser, yaml_token_t *token,
723        int literal);
724
725static int
726yaml_parser_scan_block_scalar_breaks(yaml_parser_t *parser,
727        int *indent, yaml_string_t *breaks,
728        yaml_mark_t start_mark, yaml_mark_t *end_mark);
729
730static int
731yaml_parser_scan_flow_scalar(yaml_parser_t *parser, yaml_token_t *token,
732        int single);
733
734static int
735yaml_parser_scan_plain_scalar(yaml_parser_t *parser, yaml_token_t *token);
736
737/*
738 * Get the next token.
739 */
740
741YAML_DECLARE(int)
742yaml_parser_scan(yaml_parser_t *parser, yaml_token_t *token)
743{
744    assert(parser); /* Non-NULL parser object is expected. */
745    assert(token);  /* Non-NULL token object is expected. */
746
747    /* Erase the token object. */
748
749    memset(token, 0, sizeof(yaml_token_t));
750
751    /* No tokens after STREAM-END or error. */
752
753    if (parser->stream_end_produced || parser->error) {
754        return 1;
755    }
756
757    /* Ensure that the tokens queue contains enough tokens. */
758
759    if (!parser->token_available) {
760        if (!yaml_parser_fetch_more_tokens(parser))
761            return 0;
762    }
763
764    /* Fetch the next token from the queue. */
765
766    *token = DEQUEUE(parser, parser->tokens);
767    parser->token_available = 0;
768    parser->tokens_parsed ++;
769
770    if (token->type == YAML_STREAM_END_TOKEN) {
771        parser->stream_end_produced = 1;
772    }
773
774    return 1;
775}
776
777/*
778 * Set the scanner error and return 0.
779 */
780
781static int
782yaml_parser_set_scanner_error(yaml_parser_t *parser, const char *context,
783        yaml_mark_t context_mark, const char *problem)
784{
785    parser->error = YAML_SCANNER_ERROR;
786    parser->context = context;
787    parser->context_mark = context_mark;
788    parser->problem = problem;
789    parser->problem_mark = parser->mark;
790
791    return 0;
792}
793
794/*
795 * Ensure that the tokens queue contains at least one token which can be
796 * returned to the Parser.
797 */
798
799YAML_DECLARE(int)
800yaml_parser_fetch_more_tokens(yaml_parser_t *parser)
801{
802    int need_more_tokens;
803
804    /* While we need more tokens to fetch, do it. */
805
806    while (1)
807    {
808        /*
809         * Check if we really need to fetch more tokens.
810         */
811
812        need_more_tokens = 0;
813
814        if (parser->tokens.head == parser->tokens.tail)
815        {
816            /* Queue is empty. */
817
818            need_more_tokens = 1;
819        }
820        else
821        {
822            yaml_simple_key_t *simple_key;
823
824            /* Check if any potential simple key may occupy the head position. */
825
826            if (!yaml_parser_stale_simple_keys(parser))
827                return 0;
828
829            for (simple_key = parser->simple_keys.start;
830                    simple_key != parser->simple_keys.top; simple_key++) {
831                if (simple_key->possible
832                        && simple_key->token_number == parser->tokens_parsed) {
833                    need_more_tokens = 1;
834                    break;
835                }
836            }
837        }
838
839        /* We are finished. */
840
841        if (!need_more_tokens)
842            break;
843
844        /* Fetch the next token. */
845
846        if (!yaml_parser_fetch_next_token(parser))
847            return 0;
848    }
849
850    parser->token_available = 1;
851
852    return 1;
853}
854
855/*
856 * The dispatcher for token fetchers.
857 */
858
859static int
860yaml_parser_fetch_next_token(yaml_parser_t *parser)
861{
862    /* Ensure that the buffer is initialized. */
863
864    if (!CACHE(parser, 1))
865        return 0;
866
867    /* Check if we just started scanning.  Fetch STREAM-START then. */
868
869    if (!parser->stream_start_produced)
870        return yaml_parser_fetch_stream_start(parser);
871
872    /* Eat whitespaces and comments until we reach the next token. */
873
874    if (!yaml_parser_scan_to_next_token(parser))
875        return 0;
876
877    /* Remove obsolete potential simple keys. */
878
879    if (!yaml_parser_stale_simple_keys(parser))
880        return 0;
881
882    /* Check the indentation level against the current column. */
883
884    if (!yaml_parser_unroll_indent(parser, parser->mark.column))
885        return 0;
886
887    /*
888     * Ensure that the buffer contains at least 4 characters.  4 is the length
889     * of the longest indicators ('--- ' and '... ').
890     */
891
892    if (!CACHE(parser, 4))
893        return 0;
894
895    /* Is it the end of the stream? */
896
897    if (IS_Z(parser->buffer))
898        return yaml_parser_fetch_stream_end(parser);
899
900    /* Is it a directive? */
901
902    if (parser->mark.column == 0 && CHECK(parser->buffer, '%'))
903        return yaml_parser_fetch_directive(parser);
904
905    /* Is it the document start indicator? */
906
907    if (parser->mark.column == 0
908            && CHECK_AT(parser->buffer, '-', 0)
909            && CHECK_AT(parser->buffer, '-', 1)
910            && CHECK_AT(parser->buffer, '-', 2)
911            && IS_BLANKZ_AT(parser->buffer, 3))
912        return yaml_parser_fetch_document_indicator(parser,
913                YAML_DOCUMENT_START_TOKEN);
914
915    /* Is it the document end indicator? */
916
917    if (parser->mark.column == 0
918            && CHECK_AT(parser->buffer, '.', 0)
919            && CHECK_AT(parser->buffer, '.', 1)
920            && CHECK_AT(parser->buffer, '.', 2)
921            && IS_BLANKZ_AT(parser->buffer, 3))
922        return yaml_parser_fetch_document_indicator(parser,
923                YAML_DOCUMENT_END_TOKEN);
924
925    /* Is it the flow sequence start indicator? */
926
927    if (CHECK(parser->buffer, '['))
928        return yaml_parser_fetch_flow_collection_start(parser,
929                YAML_FLOW_SEQUENCE_START_TOKEN);
930
931    /* Is it the flow mapping start indicator? */
932
933    if (CHECK(parser->buffer, '{'))
934        return yaml_parser_fetch_flow_collection_start(parser,
935                YAML_FLOW_MAPPING_START_TOKEN);
936
937    /* Is it the flow sequence end indicator? */
938
939    if (CHECK(parser->buffer, ']'))
940        return yaml_parser_fetch_flow_collection_end(parser,
941                YAML_FLOW_SEQUENCE_END_TOKEN);
942
943    /* Is it the flow mapping end indicator? */
944
945    if (CHECK(parser->buffer, '}'))
946        return yaml_parser_fetch_flow_collection_end(parser,
947                YAML_FLOW_MAPPING_END_TOKEN);
948
949    /* Is it the flow entry indicator? */
950
951    if (CHECK(parser->buffer, ','))
952        return yaml_parser_fetch_flow_entry(parser);
953
954    /* Is it the block entry indicator? */
955
956    if (CHECK(parser->buffer, '-') && IS_BLANKZ_AT(parser->buffer, 1))
957        return yaml_parser_fetch_block_entry(parser);
958
959    /* Is it the key indicator? */
960
961    if (CHECK(parser->buffer, '?')
962            && (parser->flow_level || IS_BLANKZ_AT(parser->buffer, 1)))
963        return yaml_parser_fetch_key(parser);
964
965    /* Is it the value indicator? */
966
967    if (CHECK(parser->buffer, ':')
968            && (parser->flow_level || IS_BLANKZ_AT(parser->buffer, 1)))
969        return yaml_parser_fetch_value(parser);
970
971    /* Is it an alias? */
972
973    if (CHECK(parser->buffer, '*'))
974        return yaml_parser_fetch_anchor(parser, YAML_ALIAS_TOKEN);
975
976    /* Is it an anchor? */
977
978    if (CHECK(parser->buffer, '&'))
979        return yaml_parser_fetch_anchor(parser, YAML_ANCHOR_TOKEN);
980
981    /* Is it a tag? */
982
983    if (CHECK(parser->buffer, '!'))
984        return yaml_parser_fetch_tag(parser);
985
986    /* Is it a literal scalar? */
987
988    if (CHECK(parser->buffer, '|') && !parser->flow_level)
989        return yaml_parser_fetch_block_scalar(parser, 1);
990
991    /* Is it a folded scalar? */
992
993    if (CHECK(parser->buffer, '>') && !parser->flow_level)
994        return yaml_parser_fetch_block_scalar(parser, 0);
995
996    /* Is it a single-quoted scalar? */
997
998    if (CHECK(parser->buffer, '\''))
999        return yaml_parser_fetch_flow_scalar(parser, 1);
1000
1001    /* Is it a double-quoted scalar? */
1002
1003    if (CHECK(parser->buffer, '"'))
1004        return yaml_parser_fetch_flow_scalar(parser, 0);
1005
1006    /*
1007     * Is it a plain scalar?
1008     *
1009     * A plain scalar may start with any non-blank characters except
1010     *
1011     *      '-', '?', ':', ',', '[', ']', '{', '}',
1012     *      '#', '&', '*', '!', '|', '>', '\'', '\"',
1013     *      '%', '@', '`'.
1014     *
1015     * In the block context (and, for the '-' indicator, in the flow context
1016     * too), it may also start with the characters
1017     *
1018     *      '-', '?', ':'
1019     *
1020     * if it is followed by a non-space character.
1021     *
1022     * The last rule is more restrictive than the specification requires.
1023     */
1024
1025    if (!(IS_BLANKZ(parser->buffer) || CHECK(parser->buffer, '-')
1026                || CHECK(parser->buffer, '?') || CHECK(parser->buffer, ':')
1027                || CHECK(parser->buffer, ',') || CHECK(parser->buffer, '[')
1028                || CHECK(parser->buffer, ']') || CHECK(parser->buffer, '{')
1029                || CHECK(parser->buffer, '}') || CHECK(parser->buffer, '#')
1030                || CHECK(parser->buffer, '&') || CHECK(parser->buffer, '*')
1031                || CHECK(parser->buffer, '!') || CHECK(parser->buffer, '|')
1032                || CHECK(parser->buffer, '>') || CHECK(parser->buffer, '\'')
1033                || CHECK(parser->buffer, '"') || CHECK(parser->buffer, '%')
1034                || CHECK(parser->buffer, '@') || CHECK(parser->buffer, '`')) ||
1035            (CHECK(parser->buffer, '-') && !IS_BLANK_AT(parser->buffer, 1)) ||
1036            (!parser->flow_level &&
1037             (CHECK(parser->buffer, '?') || CHECK(parser->buffer, ':'))
1038             && !IS_BLANKZ_AT(parser->buffer, 1)))
1039        return yaml_parser_fetch_plain_scalar(parser);
1040
1041    /*
1042     * If we don't determine the token type so far, it is an error.
1043     */
1044
1045    return yaml_parser_set_scanner_error(parser,
1046            "while scanning for the next token", parser->mark,
1047            "found character that cannot start any token");
1048}
1049
1050/*
1051 * Check the list of potential simple keys and remove the positions that
1052 * cannot contain simple keys anymore.
1053 */
1054
1055static int
1056yaml_parser_stale_simple_keys(yaml_parser_t *parser)
1057{
1058    yaml_simple_key_t *simple_key;
1059
1060    /* Check for a potential simple key for each flow level. */
1061
1062    for (simple_key = parser->simple_keys.start;
1063            simple_key != parser->simple_keys.top; simple_key ++)
1064    {
1065        /*
1066         * The specification requires that a simple key
1067         *
1068         *  - is limited to a single line,
1069         *  - is shorter than 1024 characters.
1070         */
1071
1072        if (simple_key->possible
1073                && (simple_key->mark.line < parser->mark.line
1074                    || simple_key->mark.index+1024 < parser->mark.index)) {
1075
1076            /* Check if the potential simple key to be removed is required. */
1077
1078            if (simple_key->required) {
1079                return yaml_parser_set_scanner_error(parser,
1080                        "while scanning a simple key", simple_key->mark,
1081                        "could not find expected ':'");
1082            }
1083
1084            simple_key->possible = 0;
1085        }
1086    }
1087
1088    return 1;
1089}
1090
1091/*
1092 * Check if a simple key may start at the current position and add it if
1093 * needed.
1094 */
1095
1096static int
1097yaml_parser_save_simple_key(yaml_parser_t *parser)
1098{
1099    /*
1100     * A simple key is required at the current position if the scanner is in
1101     * the block context and the current column coincides with the indentation
1102     * level.
1103     */
1104
1105    int required = (!parser->flow_level
1106            && parser->indent == (ptrdiff_t)parser->mark.column);
1107
1108    /*
1109     * A simple key is required only when it is the first token in the current
1110     * line.  Therefore it is always allowed.  But we add a check anyway.
1111     */
1112
1113    assert(parser->simple_key_allowed || !required);    /* Impossible. */
1114
1115    /*
1116     * If the current position may start a simple key, save it.
1117     */
1118
1119    if (parser->simple_key_allowed)
1120    {
1121        yaml_simple_key_t simple_key;
1122        simple_key.possible = 1;
1123        simple_key.required = required;
1124        simple_key.token_number =
1125            parser->tokens_parsed + (parser->tokens.tail - parser->tokens.head);
1126        simple_key.mark = parser->mark;
1127
1128        if (!yaml_parser_remove_simple_key(parser)) return 0;
1129
1130        *(parser->simple_keys.top-1) = simple_key;
1131    }
1132
1133    return 1;
1134}
1135
1136/*
1137 * Remove a potential simple key at the current flow level.
1138 */
1139
1140static int
1141yaml_parser_remove_simple_key(yaml_parser_t *parser)
1142{
1143    yaml_simple_key_t *simple_key = parser->simple_keys.top-1;
1144
1145    if (simple_key->possible)
1146    {
1147        /* If the key is required, it is an error. */
1148
1149        if (simple_key->required) {
1150            return yaml_parser_set_scanner_error(parser,
1151                    "while scanning a simple key", simple_key->mark,
1152                    "could not find expected ':'");
1153        }
1154    }
1155
1156    /* Remove the key from the stack. */
1157
1158    simple_key->possible = 0;
1159
1160    return 1;
1161}
1162
1163/*
1164 * Increase the flow level and resize the simple key list if needed.
1165 */
1166
1167static int
1168yaml_parser_increase_flow_level(yaml_parser_t *parser)
1169{
1170    yaml_simple_key_t empty_simple_key = { 0, 0, 0, { 0, 0, 0 } };
1171
1172    /* Reset the simple key on the next level. */
1173
1174    if (!PUSH(parser, parser->simple_keys, empty_simple_key))
1175        return 0;
1176
1177    /* Increase the flow level. */
1178
1179    if (parser->flow_level == INT_MAX) {
1180        parser->error = YAML_MEMORY_ERROR;
1181        return 0;
1182    }
1183
1184    parser->flow_level++;
1185
1186    return 1;
1187}
1188
1189/*
1190 * Decrease the flow level.
1191 */
1192
1193static int
1194yaml_parser_decrease_flow_level(yaml_parser_t *parser)
1195{
1196    if (parser->flow_level) {
1197        parser->flow_level --;
1198        (void)POP(parser, parser->simple_keys);
1199    }
1200
1201    return 1;
1202}
1203
1204/*
1205 * Push the current indentation level to the stack and set the new level
1206 * the current column is greater than the indentation level.  In this case,
1207 * append or insert the specified token into the token queue.
1208 *
1209 */
1210
1211static int
1212yaml_parser_roll_indent(yaml_parser_t *parser, ptrdiff_t column,
1213        ptrdiff_t number, yaml_token_type_t type, yaml_mark_t mark)
1214{
1215    yaml_token_t token;
1216
1217    /* In the flow context, do nothing. */
1218
1219    if (parser->flow_level)
1220        return 1;
1221
1222    if (parser->indent < column)
1223    {
1224        /*
1225         * Push the current indentation level to the stack and set the new
1226         * indentation level.
1227         */
1228
1229        if (!PUSH(parser, parser->indents, parser->indent))
1230            return 0;
1231
1232#if PTRDIFF_MAX > INT_MAX
1233        if (column > INT_MAX) {
1234            parser->error = YAML_MEMORY_ERROR;
1235            return 0;
1236        }
1237#endif
1238
1239        parser->indent = (int)column;
1240
1241        /* Create a token and insert it into the queue. */
1242
1243        TOKEN_INIT(token, type, mark, mark);
1244
1245        if (number == -1) {
1246            if (!ENQUEUE(parser, parser->tokens, token))
1247                return 0;
1248        }
1249        else {
1250            if (!QUEUE_INSERT(parser,
1251                        parser->tokens, number - parser->tokens_parsed, token))
1252                return 0;
1253        }
1254    }
1255
1256    return 1;
1257}
1258
1259/*
1260 * Pop indentation levels from the indents stack until the current level
1261 * becomes less or equal to the column.  For each intendation level, append
1262 * the BLOCK-END token.
1263 */
1264
1265
1266static int
1267yaml_parser_unroll_indent(yaml_parser_t *parser, ptrdiff_t column)
1268{
1269    yaml_token_t token;
1270
1271    /* In the flow context, do nothing. */
1272
1273    if (parser->flow_level)
1274        return 1;
1275
1276    /* Loop through the intendation levels in the stack. */
1277
1278    while (parser->indent > column)
1279    {
1280        /* Create a token and append it to the queue. */
1281
1282        TOKEN_INIT(token, YAML_BLOCK_END_TOKEN, parser->mark, parser->mark);
1283
1284        if (!ENQUEUE(parser, parser->tokens, token))
1285            return 0;
1286
1287        /* Pop the indentation level. */
1288
1289        parser->indent = POP(parser, parser->indents);
1290    }
1291
1292    return 1;
1293}
1294
1295/*
1296 * Initialize the scanner and produce the STREAM-START token.
1297 */
1298
1299static int
1300yaml_parser_fetch_stream_start(yaml_parser_t *parser)
1301{
1302    yaml_simple_key_t simple_key = { 0, 0, 0, { 0, 0, 0 } };
1303    yaml_token_t token;
1304
1305    /* Set the initial indentation. */
1306
1307    parser->indent = -1;
1308
1309    /* Initialize the simple key stack. */
1310
1311    if (!PUSH(parser, parser->simple_keys, simple_key))
1312        return 0;
1313
1314    /* A simple key is allowed at the beginning of the stream. */
1315
1316    parser->simple_key_allowed = 1;
1317
1318    /* We have started. */
1319
1320    parser->stream_start_produced = 1;
1321
1322    /* Create the STREAM-START token and append it to the queue. */
1323
1324    STREAM_START_TOKEN_INIT(token, parser->encoding,
1325            parser->mark, parser->mark);
1326
1327    if (!ENQUEUE(parser, parser->tokens, token))
1328        return 0;
1329
1330    return 1;
1331}
1332
1333/*
1334 * Produce the STREAM-END token and shut down the scanner.
1335 */
1336
1337static int
1338yaml_parser_fetch_stream_end(yaml_parser_t *parser)
1339{
1340    yaml_token_t token;
1341
1342    /* Force new line. */
1343
1344    if (parser->mark.column != 0) {
1345        parser->mark.column = 0;
1346        parser->mark.line ++;
1347    }
1348
1349    /* Reset the indentation level. */
1350
1351    if (!yaml_parser_unroll_indent(parser, -1))
1352        return 0;
1353
1354    /* Reset simple keys. */
1355
1356    if (!yaml_parser_remove_simple_key(parser))
1357        return 0;
1358
1359    parser->simple_key_allowed = 0;
1360
1361    /* Create the STREAM-END token and append it to the queue. */
1362
1363    STREAM_END_TOKEN_INIT(token, parser->mark, parser->mark);
1364
1365    if (!ENQUEUE(parser, parser->tokens, token))
1366        return 0;
1367
1368    return 1;
1369}
1370
1371/*
1372 * Produce a VERSION-DIRECTIVE or TAG-DIRECTIVE token.
1373 */
1374
1375static int
1376yaml_parser_fetch_directive(yaml_parser_t *parser)
1377{
1378    yaml_token_t token;
1379
1380    /* Reset the indentation level. */
1381
1382    if (!yaml_parser_unroll_indent(parser, -1))
1383        return 0;
1384
1385    /* Reset simple keys. */
1386
1387    if (!yaml_parser_remove_simple_key(parser))
1388        return 0;
1389
1390    parser->simple_key_allowed = 0;
1391
1392    /* Create the YAML-DIRECTIVE or TAG-DIRECTIVE token. */
1393
1394    if (!yaml_parser_scan_directive(parser, &token))
1395        return 0;
1396
1397    /* Append the token to the queue. */
1398
1399    if (!ENQUEUE(parser, parser->tokens, token)) {
1400        yaml_token_delete(&token);
1401        return 0;
1402    }
1403
1404    return 1;
1405}
1406
1407/*
1408 * Produce the DOCUMENT-START or DOCUMENT-END token.
1409 */
1410
1411static int
1412yaml_parser_fetch_document_indicator(yaml_parser_t *parser,
1413        yaml_token_type_t type)
1414{
1415    yaml_mark_t start_mark, end_mark;
1416    yaml_token_t token;
1417
1418    /* Reset the indentation level. */
1419
1420    if (!yaml_parser_unroll_indent(parser, -1))
1421        return 0;
1422
1423    /* Reset simple keys. */
1424
1425    if (!yaml_parser_remove_simple_key(parser))
1426        return 0;
1427
1428    parser->simple_key_allowed = 0;
1429
1430    /* Consume the token. */
1431
1432    start_mark = parser->mark;
1433
1434    SKIP(parser);
1435    SKIP(parser);
1436    SKIP(parser);
1437
1438    end_mark = parser->mark;
1439
1440    /* Create the DOCUMENT-START or DOCUMENT-END token. */
1441
1442    TOKEN_INIT(token, type, start_mark, end_mark);
1443
1444    /* Append the token to the queue. */
1445
1446    if (!ENQUEUE(parser, parser->tokens, token))
1447        return 0;
1448
1449    return 1;
1450}
1451
1452/*
1453 * Produce the FLOW-SEQUENCE-START or FLOW-MAPPING-START token.
1454 */
1455
1456static int
1457yaml_parser_fetch_flow_collection_start(yaml_parser_t *parser,
1458        yaml_token_type_t type)
1459{
1460    yaml_mark_t start_mark, end_mark;
1461    yaml_token_t token;
1462
1463    /* The indicators '[' and '{' may start a simple key. */
1464
1465    if (!yaml_parser_save_simple_key(parser))
1466        return 0;
1467
1468    /* Increase the flow level. */
1469
1470    if (!yaml_parser_increase_flow_level(parser))
1471        return 0;
1472
1473    /* A simple key may follow the indicators '[' and '{'. */
1474
1475    parser->simple_key_allowed = 1;
1476
1477    /* Consume the token. */
1478
1479    start_mark = parser->mark;
1480    SKIP(parser);
1481    end_mark = parser->mark;
1482
1483    /* Create the FLOW-SEQUENCE-START of FLOW-MAPPING-START token. */
1484
1485    TOKEN_INIT(token, type, start_mark, end_mark);
1486
1487    /* Append the token to the queue. */
1488
1489    if (!ENQUEUE(parser, parser->tokens, token))
1490        return 0;
1491
1492    return 1;
1493}
1494
1495/*
1496 * Produce the FLOW-SEQUENCE-END or FLOW-MAPPING-END token.
1497 */
1498
1499static int
1500yaml_parser_fetch_flow_collection_end(yaml_parser_t *parser,
1501        yaml_token_type_t type)
1502{
1503    yaml_mark_t start_mark, end_mark;
1504    yaml_token_t token;
1505
1506    /* Reset any potential simple key on the current flow level. */
1507
1508    if (!yaml_parser_remove_simple_key(parser))
1509        return 0;
1510
1511    /* Decrease the flow level. */
1512
1513    if (!yaml_parser_decrease_flow_level(parser))
1514        return 0;
1515
1516    /* No simple keys after the indicators ']' and '}'. */
1517
1518    parser->simple_key_allowed = 0;
1519
1520    /* Consume the token. */
1521
1522    start_mark = parser->mark;
1523    SKIP(parser);
1524    end_mark = parser->mark;
1525
1526    /* Create the FLOW-SEQUENCE-END of FLOW-MAPPING-END token. */
1527
1528    TOKEN_INIT(token, type, start_mark, end_mark);
1529
1530    /* Append the token to the queue. */
1531
1532    if (!ENQUEUE(parser, parser->tokens, token))
1533        return 0;
1534
1535    return 1;
1536}
1537
1538/*
1539 * Produce the FLOW-ENTRY token.
1540 */
1541
1542static int
1543yaml_parser_fetch_flow_entry(yaml_parser_t *parser)
1544{
1545    yaml_mark_t start_mark, end_mark;
1546    yaml_token_t token;
1547
1548    /* Reset any potential simple keys on the current flow level. */
1549
1550    if (!yaml_parser_remove_simple_key(parser))
1551        return 0;
1552
1553    /* Simple keys are allowed after ','. */
1554
1555    parser->simple_key_allowed = 1;
1556
1557    /* Consume the token. */
1558
1559    start_mark = parser->mark;
1560    SKIP(parser);
1561    end_mark = parser->mark;
1562
1563    /* Create the FLOW-ENTRY token and append it to the queue. */
1564
1565    TOKEN_INIT(token, YAML_FLOW_ENTRY_TOKEN, start_mark, end_mark);
1566
1567    if (!ENQUEUE(parser, parser->tokens, token))
1568        return 0;
1569
1570    return 1;
1571}
1572
1573/*
1574 * Produce the BLOCK-ENTRY token.
1575 */
1576
1577static int
1578yaml_parser_fetch_block_entry(yaml_parser_t *parser)
1579{
1580    yaml_mark_t start_mark, end_mark;
1581    yaml_token_t token;
1582
1583    /* Check if the scanner is in the block context. */
1584
1585    if (!parser->flow_level)
1586    {
1587        /* Check if we are allowed to start a new entry. */
1588
1589        if (!parser->simple_key_allowed) {
1590            return yaml_parser_set_scanner_error(parser, NULL, parser->mark,
1591                    "block sequence entries are not allowed in this context");
1592        }
1593
1594        /* Add the BLOCK-SEQUENCE-START token if needed. */
1595
1596        if (!yaml_parser_roll_indent(parser, parser->mark.column, -1,
1597                    YAML_BLOCK_SEQUENCE_START_TOKEN, parser->mark))
1598            return 0;
1599    }
1600    else
1601    {
1602        /*
1603         * It is an error for the '-' indicator to occur in the flow context,
1604         * but we let the Parser detect and report about it because the Parser
1605         * is able to point to the context.
1606         */
1607    }
1608
1609    /* Reset any potential simple keys on the current flow level. */
1610
1611    if (!yaml_parser_remove_simple_key(parser))
1612        return 0;
1613
1614    /* Simple keys are allowed after '-'. */
1615
1616    parser->simple_key_allowed = 1;
1617
1618    /* Consume the token. */
1619
1620    start_mark = parser->mark;
1621    SKIP(parser);
1622    end_mark = parser->mark;
1623
1624    /* Create the BLOCK-ENTRY token and append it to the queue. */
1625
1626    TOKEN_INIT(token, YAML_BLOCK_ENTRY_TOKEN, start_mark, end_mark);
1627
1628    if (!ENQUEUE(parser, parser->tokens, token))
1629        return 0;
1630
1631    return 1;
1632}
1633
1634/*
1635 * Produce the KEY token.
1636 */
1637
1638static int
1639yaml_parser_fetch_key(yaml_parser_t *parser)
1640{
1641    yaml_mark_t start_mark, end_mark;
1642    yaml_token_t token;
1643
1644    /* In the block context, additional checks are required. */
1645
1646    if (!parser->flow_level)
1647    {
1648        /* Check if we are allowed to start a new key (not nessesary simple). */
1649
1650        if (!parser->simple_key_allowed) {
1651            return yaml_parser_set_scanner_error(parser, NULL, parser->mark,
1652                    "mapping keys are not allowed in this context");
1653        }
1654
1655        /* Add the BLOCK-MAPPING-START token if needed. */
1656
1657        if (!yaml_parser_roll_indent(parser, parser->mark.column, -1,
1658                    YAML_BLOCK_MAPPING_START_TOKEN, parser->mark))
1659            return 0;
1660    }
1661
1662    /* Reset any potential simple keys on the current flow level. */
1663
1664    if (!yaml_parser_remove_simple_key(parser))
1665        return 0;
1666
1667    /* Simple keys are allowed after '?' in the block context. */
1668
1669    parser->simple_key_allowed = (!parser->flow_level);
1670
1671    /* Consume the token. */
1672
1673    start_mark = parser->mark;
1674    SKIP(parser);
1675    end_mark = parser->mark;
1676
1677    /* Create the KEY token and append it to the queue. */
1678
1679    TOKEN_INIT(token, YAML_KEY_TOKEN, start_mark, end_mark);
1680
1681    if (!ENQUEUE(parser, parser->tokens, token))
1682        return 0;
1683
1684    return 1;
1685}
1686
1687/*
1688 * Produce the VALUE token.
1689 */
1690
1691static int
1692yaml_parser_fetch_value(yaml_parser_t *parser)
1693{
1694    yaml_mark_t start_mark, end_mark;
1695    yaml_token_t token;
1696    yaml_simple_key_t *simple_key = parser->simple_keys.top-1;
1697
1698    /* Have we found a simple key? */
1699
1700    if (simple_key->possible)
1701    {
1702
1703        /* Create the KEY token and insert it into the queue. */
1704
1705        TOKEN_INIT(token, YAML_KEY_TOKEN, simple_key->mark, simple_key->mark);
1706
1707        if (!QUEUE_INSERT(parser, parser->tokens,
1708                    simple_key->token_number - parser->tokens_parsed, token))
1709            return 0;
1710
1711        /* In the block context, we may need to add the BLOCK-MAPPING-START token. */
1712
1713        if (!yaml_parser_roll_indent(parser, simple_key->mark.column,
1714                    simple_key->token_number,
1715                    YAML_BLOCK_MAPPING_START_TOKEN, simple_key->mark))
1716            return 0;
1717
1718        /* Remove the simple key. */
1719
1720        simple_key->possible = 0;
1721
1722        /* A simple key cannot follow another simple key. */
1723
1724        parser->simple_key_allowed = 0;
1725    }
1726    else
1727    {
1728        /* The ':' indicator follows a complex key. */
1729
1730        /* In the block context, extra checks are required. */
1731
1732        if (!parser->flow_level)
1733        {
1734            /* Check if we are allowed to start a complex value. */
1735
1736            if (!parser->simple_key_allowed) {
1737                return yaml_parser_set_scanner_error(parser, NULL, parser->mark,
1738                        "mapping values are not allowed in this context");
1739            }
1740
1741            /* Add the BLOCK-MAPPING-START token if needed. */
1742
1743            if (!yaml_parser_roll_indent(parser, parser->mark.column, -1,
1744                        YAML_BLOCK_MAPPING_START_TOKEN, parser->mark))
1745                return 0;
1746        }
1747
1748        /* Simple keys after ':' are allowed in the block context. */
1749
1750        parser->simple_key_allowed = (!parser->flow_level);
1751    }
1752
1753    /* Consume the token. */
1754
1755    start_mark = parser->mark;
1756    SKIP(parser);
1757    end_mark = parser->mark;
1758
1759    /* Create the VALUE token and append it to the queue. */
1760
1761    TOKEN_INIT(token, YAML_VALUE_TOKEN, start_mark, end_mark);
1762
1763    if (!ENQUEUE(parser, parser->tokens, token))
1764        return 0;
1765
1766    return 1;
1767}
1768
1769/*
1770 * Produce the ALIAS or ANCHOR token.
1771 */
1772
1773static int
1774yaml_parser_fetch_anchor(yaml_parser_t *parser, yaml_token_type_t type)
1775{
1776    yaml_token_t token;
1777
1778    /* An anchor or an alias could be a simple key. */
1779
1780    if (!yaml_parser_save_simple_key(parser))
1781        return 0;
1782
1783    /* A simple key cannot follow an anchor or an alias. */
1784
1785    parser->simple_key_allowed = 0;
1786
1787    /* Create the ALIAS or ANCHOR token and append it to the queue. */
1788
1789    if (!yaml_parser_scan_anchor(parser, &token, type))
1790        return 0;
1791
1792    if (!ENQUEUE(parser, parser->tokens, token)) {
1793        yaml_token_delete(&token);
1794        return 0;
1795    }
1796    return 1;
1797}
1798
1799/*
1800 * Produce the TAG token.
1801 */
1802
1803static int
1804yaml_parser_fetch_tag(yaml_parser_t *parser)
1805{
1806    yaml_token_t token;
1807
1808    /* A tag could be a simple key. */
1809
1810    if (!yaml_parser_save_simple_key(parser))
1811        return 0;
1812
1813    /* A simple key cannot follow a tag. */
1814
1815    parser->simple_key_allowed = 0;
1816
1817    /* Create the TAG token and append it to the queue. */
1818
1819    if (!yaml_parser_scan_tag(parser, &token))
1820        return 0;
1821
1822    if (!ENQUEUE(parser, parser->tokens, token)) {
1823        yaml_token_delete(&token);
1824        return 0;
1825    }
1826
1827    return 1;
1828}
1829
1830/*
1831 * Produce the SCALAR(...,literal) or SCALAR(...,folded) tokens.
1832 */
1833
1834static int
1835yaml_parser_fetch_block_scalar(yaml_parser_t *parser, int literal)
1836{
1837    yaml_token_t token;
1838
1839    /* Remove any potential simple keys. */
1840
1841    if (!yaml_parser_remove_simple_key(parser))
1842        return 0;
1843
1844    /* A simple key may follow a block scalar. */
1845
1846    parser->simple_key_allowed = 1;
1847
1848    /* Create the SCALAR token and append it to the queue. */
1849
1850    if (!yaml_parser_scan_block_scalar(parser, &token, literal))
1851        return 0;
1852
1853    if (!ENQUEUE(parser, parser->tokens, token)) {
1854        yaml_token_delete(&token);
1855        return 0;
1856    }
1857
1858    return 1;
1859}
1860
1861/*
1862 * Produce the SCALAR(...,single-quoted) or SCALAR(...,double-quoted) tokens.
1863 */
1864
1865static int
1866yaml_parser_fetch_flow_scalar(yaml_parser_t *parser, int single)
1867{
1868    yaml_token_t token;
1869
1870    /* A plain scalar could be a simple key. */
1871
1872    if (!yaml_parser_save_simple_key(parser))
1873        return 0;
1874
1875    /* A simple key cannot follow a flow scalar. */
1876
1877    parser->simple_key_allowed = 0;
1878
1879    /* Create the SCALAR token and append it to the queue. */
1880
1881    if (!yaml_parser_scan_flow_scalar(parser, &token, single))
1882        return 0;
1883
1884    if (!ENQUEUE(parser, parser->tokens, token)) {
1885        yaml_token_delete(&token);
1886        return 0;
1887    }
1888
1889    return 1;
1890}
1891
1892/*
1893 * Produce the SCALAR(...,plain) token.
1894 */
1895
1896static int
1897yaml_parser_fetch_plain_scalar(yaml_parser_t *parser)
1898{
1899    yaml_token_t token;
1900
1901    /* A plain scalar could be a simple key. */
1902
1903    if (!yaml_parser_save_simple_key(parser))
1904        return 0;
1905
1906    /* A simple key cannot follow a flow scalar. */
1907
1908    parser->simple_key_allowed = 0;
1909
1910    /* Create the SCALAR token and append it to the queue. */
1911
1912    if (!yaml_parser_scan_plain_scalar(parser, &token))
1913        return 0;
1914
1915    if (!ENQUEUE(parser, parser->tokens, token)) {
1916        yaml_token_delete(&token);
1917        return 0;
1918    }
1919
1920    return 1;
1921}
1922
1923/*
1924 * Eat whitespaces and comments until the next token is found.
1925 */
1926
1927static int
1928yaml_parser_scan_to_next_token(yaml_parser_t *parser)
1929{
1930    /* Until the next token is not found. */
1931
1932    while (1)
1933    {
1934        /* Allow the BOM mark to start a line. */
1935
1936        if (!CACHE(parser, 1)) return 0;
1937
1938        if (parser->mark.column == 0 && IS_BOM(parser->buffer))
1939            SKIP(parser);
1940
1941        /*
1942         * Eat whitespaces.
1943         *
1944         * Tabs are allowed:
1945         *
1946         *  - in the flow context;
1947         *  - in the block context, but not at the beginning of the line or
1948         *  after '-', '?', or ':' (complex value).
1949         */
1950
1951        if (!CACHE(parser, 1)) return 0;
1952
1953        while (CHECK(parser->buffer,' ') ||
1954                ((parser->flow_level || !parser->simple_key_allowed) &&
1955                 CHECK(parser->buffer, '\t'))) {
1956            SKIP(parser);
1957            if (!CACHE(parser, 1)) return 0;
1958        }
1959
1960        /* Eat a comment until a line break. */
1961
1962        if (CHECK(parser->buffer, '#')) {
1963            while (!IS_BREAKZ(parser->buffer)) {
1964                SKIP(parser);
1965                if (!CACHE(parser, 1)) return 0;
1966            }
1967        }
1968
1969        /* If it is a line break, eat it. */
1970
1971        if (IS_BREAK(parser->buffer))
1972        {
1973            if (!CACHE(parser, 2)) return 0;
1974            SKIP_LINE(parser);
1975
1976            /* In the block context, a new line may start a simple key. */
1977
1978            if (!parser->flow_level) {
1979                parser->simple_key_allowed = 1;
1980            }
1981        }
1982        else
1983        {
1984            /* We have found a token. */
1985
1986            break;
1987        }
1988    }
1989
1990    return 1;
1991}
1992
1993/*
1994 * Scan a YAML-DIRECTIVE or TAG-DIRECTIVE token.
1995 *
1996 * Scope:
1997 *      %YAML    1.1    # a comment \n
1998 *      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1999 *      %TAG    !yaml!  tag:yaml.org,2002:  \n
2000 *      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2001 */
2002
2003int
2004yaml_parser_scan_directive(yaml_parser_t *parser, yaml_token_t *token)
2005{
2006    yaml_mark_t start_mark, end_mark;
2007    yaml_char_t *name = NULL;
2008    int major, minor;
2009    yaml_char_t *handle = NULL, *prefix = NULL;
2010
2011    /* Eat '%'. */
2012
2013    start_mark = parser->mark;
2014
2015    SKIP(parser);
2016
2017    /* Scan the directive name. */
2018
2019    if (!yaml_parser_scan_directive_name(parser, start_mark, &name))
2020        goto error;
2021
2022    /* Is it a YAML directive? */
2023
2024    if (strcmp((char *)name, "YAML") == 0)
2025    {
2026        /* Scan the VERSION directive value. */
2027
2028        if (!yaml_parser_scan_version_directive_value(parser, start_mark,
2029                    &major, &minor))
2030            goto error;
2031
2032        end_mark = parser->mark;
2033
2034        /* Create a VERSION-DIRECTIVE token. */
2035
2036        VERSION_DIRECTIVE_TOKEN_INIT(*token, major, minor,
2037                start_mark, end_mark);
2038    }
2039
2040    /* Is it a TAG directive? */
2041
2042    else if (strcmp((char *)name, "TAG") == 0)
2043    {
2044        /* Scan the TAG directive value. */
2045
2046        if (!yaml_parser_scan_tag_directive_value(parser, start_mark,
2047                    &handle, &prefix))
2048            goto error;
2049
2050        end_mark = parser->mark;
2051
2052        /* Create a TAG-DIRECTIVE token. */
2053
2054        TAG_DIRECTIVE_TOKEN_INIT(*token, handle, prefix,
2055                start_mark, end_mark);
2056    }
2057
2058    /* Unknown directive. */
2059
2060    else
2061    {
2062        yaml_parser_set_scanner_error(parser, "while scanning a directive",
2063                start_mark, "found uknown directive name");
2064        goto error;
2065    }
2066
2067    /* Eat the rest of the line including any comments. */
2068
2069    if (!CACHE(parser, 1)) goto error;
2070
2071    while (IS_BLANK(parser->buffer)) {
2072        SKIP(parser);
2073        if (!CACHE(parser, 1)) goto error;
2074    }
2075
2076    if (CHECK(parser->buffer, '#')) {
2077        while (!IS_BREAKZ(parser->buffer)) {
2078            SKIP(parser);
2079            if (!CACHE(parser, 1)) goto error;
2080        }
2081    }
2082
2083    /* Check if we are at the end of the line. */
2084
2085    if (!IS_BREAKZ(parser->buffer)) {
2086        yaml_parser_set_scanner_error(parser, "while scanning a directive",
2087                start_mark, "did not find expected comment or line break");
2088        goto error;
2089    }
2090
2091    /* Eat a line break. */
2092
2093    if (IS_BREAK(parser->buffer)) {
2094        if (!CACHE(parser, 2)) goto error;
2095        SKIP_LINE(parser);
2096    }
2097
2098    yaml_free(name);
2099
2100    return 1;
2101
2102error:
2103    yaml_free(prefix);
2104    yaml_free(handle);
2105    yaml_free(name);
2106    return 0;
2107}
2108
2109/*
2110 * Scan the directive name.
2111 *
2112 * Scope:
2113 *      %YAML   1.1     # a comment \n
2114 *       ^^^^
2115 *      %TAG    !yaml!  tag:yaml.org,2002:  \n
2116 *       ^^^
2117 */
2118
2119static int
2120yaml_parser_scan_directive_name(yaml_parser_t *parser,
2121        yaml_mark_t start_mark, yaml_char_t **name)
2122{
2123    yaml_string_t string = NULL_STRING;
2124
2125    if (!STRING_INIT(parser, string, INITIAL_STRING_SIZE)) goto error;
2126
2127    /* Consume the directive name. */
2128
2129    if (!CACHE(parser, 1)) goto error;
2130
2131    while (IS_ALPHA(parser->buffer))
2132    {
2133        if (!READ(parser, string)) goto error;
2134        if (!CACHE(parser, 1)) goto error;
2135    }
2136
2137    /* Check if the name is empty. */
2138
2139    if (string.start == string.pointer) {
2140        yaml_parser_set_scanner_error(parser, "while scanning a directive",
2141                start_mark, "could not find expected directive name");
2142        goto error;
2143    }
2144
2145    /* Check for an blank character after the name. */
2146
2147    if (!IS_BLANKZ(parser->buffer)) {
2148        yaml_parser_set_scanner_error(parser, "while scanning a directive",
2149                start_mark, "found unexpected non-alphabetical character");
2150        goto error;
2151    }
2152
2153    *name = string.start;
2154
2155    return 1;
2156
2157error:
2158    STRING_DEL(parser, string);
2159    return 0;
2160}
2161
2162/*
2163 * Scan the value of VERSION-DIRECTIVE.
2164 *
2165 * Scope:
2166 *      %YAML   1.1     # a comment \n
2167 *           ^^^^^^
2168 */
2169
2170static int
2171yaml_parser_scan_version_directive_value(yaml_parser_t *parser,
2172        yaml_mark_t start_mark, int *major, int *minor)
2173{
2174    /* Eat whitespaces. */
2175
2176    if (!CACHE(parser, 1)) return 0;
2177
2178    while (IS_BLANK(parser->buffer)) {
2179        SKIP(parser);
2180        if (!CACHE(parser, 1)) return 0;
2181    }
2182
2183    /* Consume the major version number. */
2184
2185    if (!yaml_parser_scan_version_directive_number(parser, start_mark, major))
2186        return 0;
2187
2188    /* Eat '.'. */
2189
2190    if (!CHECK(parser->buffer, '.')) {
2191        return yaml_parser_set_scanner_error(parser, "while scanning a %YAML directive",
2192                start_mark, "did not find expected digit or '.' character");
2193    }
2194
2195    SKIP(parser);
2196
2197    /* Consume the minor version number. */
2198
2199    if (!yaml_parser_scan_version_directive_number(parser, start_mark, minor))
2200        return 0;
2201
2202    return 1;
2203}
2204
2205#define MAX_NUMBER_LENGTH   9
2206
2207/*
2208 * Scan the version number of VERSION-DIRECTIVE.
2209 *
2210 * Scope:
2211 *      %YAML   1.1     # a comment \n
2212 *              ^
2213 *      %YAML   1.1     # a comment \n
2214 *                ^
2215 */
2216
2217static int
2218yaml_parser_scan_version_directive_number(yaml_parser_t *parser,
2219        yaml_mark_t start_mark, int *number)
2220{
2221    int value = 0;
2222    size_t length = 0;
2223
2224    /* Repeat while the next character is digit. */
2225
2226    if (!CACHE(parser, 1)) return 0;
2227
2228    while (IS_DIGIT(parser->buffer))
2229    {
2230        /* Check if the number is too long. */
2231
2232        if (++length > MAX_NUMBER_LENGTH) {
2233            return yaml_parser_set_scanner_error(parser, "while scanning a %YAML directive",
2234                    start_mark, "found extremely long version number");
2235        }
2236
2237        value = value*10 + AS_DIGIT(parser->buffer);
2238
2239        SKIP(parser);
2240
2241        if (!CACHE(parser, 1)) return 0;
2242    }
2243
2244    /* Check if the number was present. */
2245
2246    if (!length) {
2247        return yaml_parser_set_scanner_error(parser, "while scanning a %YAML directive",
2248                start_mark, "did not find expected version number");
2249    }
2250
2251    *number = value;
2252
2253    return 1;
2254}
2255
2256/*
2257 * Scan the value of a TAG-DIRECTIVE token.
2258 *
2259 * Scope:
2260 *      %TAG    !yaml!  tag:yaml.org,2002:  \n
2261 *          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2262 */
2263
2264static int
2265yaml_parser_scan_tag_directive_value(yaml_parser_t *parser,
2266        yaml_mark_t start_mark, yaml_char_t **handle, yaml_char_t **prefix)
2267{
2268    yaml_char_t *handle_value = NULL;
2269    yaml_char_t *prefix_value = NULL;
2270
2271    /* Eat whitespaces. */
2272
2273    if (!CACHE(parser, 1)) goto error;
2274
2275    while (IS_BLANK(parser->buffer)) {
2276        SKIP(parser);
2277        if (!CACHE(parser, 1)) goto error;
2278    }
2279
2280    /* Scan a handle. */
2281
2282    if (!yaml_parser_scan_tag_handle(parser, 1, start_mark, &handle_value))
2283        goto error;
2284
2285    /* Expect a whitespace. */
2286
2287    if (!CACHE(parser, 1)) goto error;
2288
2289    if (!IS_BLANK(parser->buffer)) {
2290        yaml_parser_set_scanner_error(parser, "while scanning a %TAG directive",
2291                start_mark, "did not find expected whitespace");
2292        goto error;
2293    }
2294
2295    /* Eat whitespaces. */
2296
2297    while (IS_BLANK(parser->buffer)) {
2298        SKIP(parser);
2299        if (!CACHE(parser, 1)) goto error;
2300    }
2301
2302    /* Scan a prefix. */
2303
2304    if (!yaml_parser_scan_tag_uri(parser, 1, NULL, start_mark, &prefix_value))
2305        goto error;
2306
2307    /* Expect a whitespace or line break. */
2308
2309    if (!CACHE(parser, 1)) goto error;
2310
2311    if (!IS_BLANKZ(parser->buffer)) {
2312        yaml_parser_set_scanner_error(parser, "while scanning a %TAG directive",
2313                start_mark, "did not find expected whitespace or line break");
2314        goto error;
2315    }
2316
2317    *handle = handle_value;
2318    *prefix = prefix_value;
2319
2320    return 1;
2321
2322error:
2323    yaml_free(handle_value);
2324    yaml_free(prefix_value);
2325    return 0;
2326}
2327
2328static int
2329yaml_parser_scan_anchor(yaml_parser_t *parser, yaml_token_t *token,
2330        yaml_token_type_t type)
2331{
2332    int length = 0;
2333    yaml_mark_t start_mark, end_mark;
2334    yaml_string_t string = NULL_STRING;
2335
2336    if (!STRING_INIT(parser, string, INITIAL_STRING_SIZE)) goto error;
2337
2338    /* Eat the indicator character. */
2339
2340    start_mark = parser->mark;
2341
2342    SKIP(parser);
2343
2344    /* Consume the value. */
2345
2346    if (!CACHE(parser, 1)) goto error;
2347
2348    while (IS_ALPHA(parser->buffer)) {
2349        if (!READ(parser, string)) goto error;
2350        if (!CACHE(parser, 1)) goto error;
2351        length ++;
2352    }
2353
2354    end_mark = parser->mark;
2355
2356    /*
2357     * Check if length of the anchor is greater than 0 and it is followed by
2358     * a whitespace character or one of the indicators:
2359     *
2360     *      '?', ':', ',', ']', '}', '%', '@', '`'.
2361     */
2362
2363    if (!length || !(IS_BLANKZ(parser->buffer) || CHECK(parser->buffer, '?')
2364                || CHECK(parser->buffer, ':') || CHECK(parser->buffer, ',')
2365                || CHECK(parser->buffer, ']') || CHECK(parser->buffer, '}')
2366                || CHECK(parser->buffer, '%') || CHECK(parser->buffer, '@')
2367                || CHECK(parser->buffer, '`'))) {
2368        yaml_parser_set_scanner_error(parser, type == YAML_ANCHOR_TOKEN ?
2369                "while scanning an anchor" : "while scanning an alias", start_mark,
2370                "did not find expected alphabetic or numeric character");
2371        goto error;
2372    }
2373
2374    /* Create a token. */
2375
2376    if (type == YAML_ANCHOR_TOKEN) {
2377        ANCHOR_TOKEN_INIT(*token, string.start, start_mark, end_mark);
2378    }
2379    else {
2380        ALIAS_TOKEN_INIT(*token, string.start, start_mark, end_mark);
2381    }
2382
2383    return 1;
2384
2385error:
2386    STRING_DEL(parser, string);
2387    return 0;
2388}
2389
2390/*
2391 * Scan a TAG token.
2392 */
2393
2394static int
2395yaml_parser_scan_tag(yaml_parser_t *parser, yaml_token_t *token)
2396{
2397    yaml_char_t *handle = NULL;
2398    yaml_char_t *suffix = NULL;
2399    yaml_mark_t start_mark, end_mark;
2400
2401    start_mark = parser->mark;
2402
2403    /* Check if the tag is in the canonical form. */
2404
2405    if (!CACHE(parser, 2)) goto error;
2406
2407    if (CHECK_AT(parser->buffer, '<', 1))
2408    {
2409        /* Set the handle to '' */
2410
2411        handle = yaml_malloc(1);
2412        if (!handle) goto error;
2413        handle[0] = '\0';
2414
2415        /* Eat '!<' */
2416
2417        SKIP(parser);
2418        SKIP(parser);
2419
2420        /* Consume the tag value. */
2421
2422        if (!yaml_parser_scan_tag_uri(parser, 0, NULL, start_mark, &suffix))
2423            goto error;
2424
2425        /* Check for '>' and eat it. */
2426
2427        if (!CHECK(parser->buffer, '>')) {
2428            yaml_parser_set_scanner_error(parser, "while scanning a tag",
2429                    start_mark, "did not find the expected '>'");
2430            goto error;
2431        }
2432
2433        SKIP(parser);
2434    }
2435    else
2436    {
2437        /* The tag has either the '!suffix' or the '!handle!suffix' form. */
2438
2439        /* First, try to scan a handle. */
2440
2441        if (!yaml_parser_scan_tag_handle(parser, 0, start_mark, &handle))
2442            goto error;
2443
2444        /* Check if it is, indeed, handle. */
2445
2446        if (handle[0] == '!' && handle[1] != '\0' && handle[strlen((char *)handle)-1] == '!')
2447        {
2448            /* Scan the suffix now. */
2449
2450            if (!yaml_parser_scan_tag_uri(parser, 0, NULL, start_mark, &suffix))
2451                goto error;
2452        }
2453        else
2454        {
2455            /* It wasn't a handle after all.  Scan the rest of the tag. */
2456
2457            if (!yaml_parser_scan_tag_uri(parser, 0, handle, start_mark, &suffix))
2458                goto error;
2459
2460            /* Set the handle to '!'. */
2461
2462            yaml_free(handle);
2463            handle = yaml_malloc(2);
2464            if (!handle) goto error;
2465            handle[0] = '!';
2466            handle[1] = '\0';
2467
2468            /*
2469             * A special case: the '!' tag.  Set the handle to '' and the
2470             * suffix to '!'.
2471             */
2472
2473            if (suffix[0] == '\0') {
2474                yaml_char_t *tmp = handle;
2475                handle = suffix;
2476                suffix = tmp;
2477            }
2478        }
2479    }
2480
2481    /* Check the character which ends the tag. */
2482
2483    if (!CACHE(parser, 1)) goto error;
2484
2485    if (!IS_BLANKZ(parser->buffer)) {
2486        yaml_parser_set_scanner_error(parser, "while scanning a tag",
2487                start_mark, "did not find expected whitespace or line break");
2488        goto error;
2489    }
2490
2491    end_mark = parser->mark;
2492
2493    /* Create a token. */
2494
2495    TAG_TOKEN_INIT(*token, handle, suffix, start_mark, end_mark);
2496
2497    return 1;
2498
2499error:
2500    yaml_free(handle);
2501    yaml_free(suffix);
2502    return 0;
2503}
2504
2505/*
2506 * Scan a tag handle.
2507 */
2508
2509static int
2510yaml_parser_scan_tag_handle(yaml_parser_t *parser, int directive,
2511        yaml_mark_t start_mark, yaml_char_t **handle)
2512{
2513    yaml_string_t string = NULL_STRING;
2514
2515    if (!STRING_INIT(parser, string, INITIAL_STRING_SIZE)) goto error;
2516
2517    /* Check the initial '!' character. */
2518
2519    if (!CACHE(parser, 1)) goto error;
2520
2521    if (!CHECK(parser->buffer, '!')) {
2522        yaml_parser_set_scanner_error(parser, directive ?
2523                "while scanning a tag directive" : "while scanning a tag",
2524                start_mark, "did not find expected '!'");
2525        goto error;
2526    }
2527
2528    /* Copy the '!' character. */
2529
2530    if (!READ(parser, string)) goto error;
2531
2532    /* Copy all subsequent alphabetical and numerical characters. */
2533
2534    if (!CACHE(parser, 1)) goto error;
2535
2536    while (IS_ALPHA(parser->buffer))
2537    {
2538        if (!READ(parser, string)) goto error;
2539        if (!CACHE(parser, 1)) goto error;
2540    }
2541
2542    /* Check if the trailing character is '!' and copy it. */
2543
2544    if (CHECK(parser->buffer, '!'))
2545    {
2546        if (!READ(parser, string)) goto error;
2547    }
2548    else
2549    {
2550        /*
2551         * It's either the '!' tag or not really a tag handle.  If it's a %TAG
2552         * directive, it's an error.  If it's a tag token, it must be a part of
2553         * URI.
2554         */
2555
2556        if (directive && !(string.start[0] == '!' && string.start[1] == '\0')) {
2557            yaml_parser_set_scanner_error(parser, "while parsing a tag directive",
2558                    start_mark, "did not find expected '!'");
2559            goto error;
2560        }
2561    }
2562
2563    *handle = string.start;
2564
2565    return 1;
2566
2567error:
2568    STRING_DEL(parser, string);
2569    return 0;
2570}
2571
2572/*
2573 * Scan a tag.
2574 */
2575
2576static int
2577yaml_parser_scan_tag_uri(yaml_parser_t *parser, int directive,
2578        yaml_char_t *head, yaml_mark_t start_mark, yaml_char_t **uri)
2579{
2580    size_t length = head ? strlen((char *)head) : 0;
2581    yaml_string_t string = NULL_STRING;
2582
2583    if (!STRING_INIT(parser, string, INITIAL_STRING_SIZE)) goto error;
2584
2585    /* Resize the string to include the head. */
2586
2587    while ((size_t)(string.end - string.start) <= length) {
2588        if (!yaml_string_extend(&string.start, &string.pointer, &string.end)) {
2589            parser->error = YAML_MEMORY_ERROR;
2590            goto error;
2591        }
2592    }
2593
2594    /*
2595     * Copy the head if needed.
2596     *
2597     * Note that we don't copy the leading '!' character.
2598     */
2599
2600    if (length > 1) {
2601        memcpy(string.start, head+1, length-1);
2602        string.pointer += length-1;
2603    }
2604
2605    /* Scan the tag. */
2606
2607    if (!CACHE(parser, 1)) goto error;
2608
2609    /*
2610     * The set of characters that may appear in URI is as follows:
2611     *
2612     *      '0'-'9', 'A'-'Z', 'a'-'z', '_', '-', ';', '/', '?', ':', '@', '&',
2613     *      '=', '+', '$', ',', '.', '!', '~', '*', '\'', '(', ')', '[', ']',
2614     *      '%'.
2615     */
2616
2617    while (IS_ALPHA(parser->buffer) || CHECK(parser->buffer, ';')
2618            || CHECK(parser->buffer, '/') || CHECK(parser->buffer, '?')
2619            || CHECK(parser->buffer, ':') || CHECK(parser->buffer, '@')
2620            || CHECK(parser->buffer, '&') || CHECK(parser->buffer, '=')
2621            || CHECK(parser->buffer, '+') || CHECK(parser->buffer, '$')
2622            || CHECK(parser->buffer, ',') || CHECK(parser->buffer, '.')
2623            || CHECK(parser->buffer, '!') || CHECK(parser->buffer, '~')
2624            || CHECK(parser->buffer, '*') || CHECK(parser->buffer, '\'')
2625            || CHECK(parser->buffer, '(') || CHECK(parser->buffer, ')')
2626            || CHECK(parser->buffer, '[') || CHECK(parser->buffer, ']')
2627            || CHECK(parser->buffer, '%'))
2628    {
2629        /* Check if it is a URI-escape sequence. */
2630
2631        if (CHECK(parser->buffer, '%')) {
2632            if (!STRING_EXTEND(parser, string))
2633                goto error;
2634
2635            if (!yaml_parser_scan_uri_escapes(parser,
2636                        directive, start_mark, &string)) goto error;
2637        }
2638        else {
2639            if (!READ(parser, string)) goto error;
2640        }
2641
2642        length ++;
2643        if (!CACHE(parser, 1)) goto error;
2644    }
2645
2646    /* Check if the tag is non-empty. */
2647
2648    if (!length) {
2649        if (!STRING_EXTEND(parser, string))
2650            goto error;
2651
2652        yaml_parser_set_scanner_error(parser, directive ?
2653                "while parsing a %TAG directive" : "while parsing a tag",
2654                start_mark, "did not find expected tag URI");
2655        goto error;
2656    }
2657
2658    *uri = string.start;
2659
2660    return 1;
2661
2662error:
2663    STRING_DEL(parser, string);
2664    return 0;
2665}
2666
2667/*
2668 * Decode an URI-escape sequence corresponding to a single UTF-8 character.
2669 */
2670
2671static int
2672yaml_parser_scan_uri_escapes(yaml_parser_t *parser, int directive,
2673        yaml_mark_t start_mark, yaml_string_t *string)
2674{
2675    int width = 0;
2676
2677    /* Decode the required number of characters. */
2678
2679    do {
2680
2681        unsigned char octet = 0;
2682
2683        /* Check for a URI-escaped octet. */
2684
2685        if (!CACHE(parser, 3)) return 0;
2686
2687        if (!(CHECK(parser->buffer, '%')
2688                    && IS_HEX_AT(parser->buffer, 1)
2689                    && IS_HEX_AT(parser->buffer, 2))) {
2690            return yaml_parser_set_scanner_error(parser, directive ?
2691                    "while parsing a %TAG directive" : "while parsing a tag",
2692                    start_mark, "did not find URI escaped octet");
2693        }
2694
2695        /* Get the octet. */
2696
2697        octet = (AS_HEX_AT(parser->buffer, 1) << 4) + AS_HEX_AT(parser->buffer, 2);
2698
2699        /* If it is the leading octet, determine the length of the UTF-8 sequence. */
2700
2701        if (!width)
2702        {
2703            width = (octet & 0x80) == 0x00 ? 1 :
2704                    (octet & 0xE0) == 0xC0 ? 2 :
2705                    (octet & 0xF0) == 0xE0 ? 3 :
2706                    (octet & 0xF8) == 0xF0 ? 4 : 0;
2707            if (!width) {
2708                return yaml_parser_set_scanner_error(parser, directive ?
2709                        "while parsing a %TAG directive" : "while parsing a tag",
2710                        start_mark, "found an incorrect leading UTF-8 octet");
2711            }
2712        }
2713        else
2714        {
2715            /* Check if the trailing octet is correct. */
2716
2717            if ((octet & 0xC0) != 0x80) {
2718                return yaml_parser_set_scanner_error(parser, directive ?
2719                        "while parsing a %TAG directive" : "while parsing a tag",
2720                        start_mark, "found an incorrect trailing UTF-8 octet");
2721            }
2722        }
2723
2724        /* Copy the octet and move the pointers. */
2725
2726        *(string->pointer++) = octet;
2727        SKIP(parser);
2728        SKIP(parser);
2729        SKIP(parser);
2730
2731    } while (--width);
2732
2733    return 1;
2734}
2735
2736/*
2737 * Scan a block scalar.
2738 */
2739
2740static int
2741yaml_parser_scan_block_scalar(yaml_parser_t *parser, yaml_token_t *token,
2742        int literal)
2743{
2744    yaml_mark_t start_mark;
2745    yaml_mark_t end_mark;
2746    yaml_string_t string = NULL_STRING;
2747    yaml_string_t leading_break = NULL_STRING;
2748    yaml_string_t trailing_breaks = NULL_STRING;
2749    int chomping = 0;
2750    int increment = 0;
2751    int indent = 0;
2752    int leading_blank = 0;
2753    int trailing_blank = 0;
2754
2755    if (!STRING_INIT(parser, string, INITIAL_STRING_SIZE)) goto error;
2756    if (!STRING_INIT(parser, leading_break, INITIAL_STRING_SIZE)) goto error;
2757    if (!STRING_INIT(parser, trailing_breaks, INITIAL_STRING_SIZE)) goto error;
2758
2759    /* Eat the indicator '|' or '>'. */
2760
2761    start_mark = parser->mark;
2762
2763    SKIP(parser);
2764
2765    /* Scan the additional block scalar indicators. */
2766
2767    if (!CACHE(parser, 1)) goto error;
2768
2769    /* Check for a chomping indicator. */
2770
2771    if (CHECK(parser->buffer, '+') || CHECK(parser->buffer, '-'))
2772    {
2773        /* Set the chomping method and eat the indicator. */
2774
2775        chomping = CHECK(parser->buffer, '+') ? +1 : -1;
2776
2777        SKIP(parser);
2778
2779        /* Check for an indentation indicator. */
2780
2781        if (!CACHE(parser, 1)) goto error;
2782
2783        if (IS_DIGIT(parser->buffer))
2784        {
2785            /* Check that the intendation is greater than 0. */
2786
2787            if (CHECK(parser->buffer, '0')) {
2788                yaml_parser_set_scanner_error(parser, "while scanning a block scalar",
2789                        start_mark, "found an intendation indicator equal to 0");
2790                goto error;
2791            }
2792
2793            /* Get the intendation level and eat the indicator. */
2794
2795            increment = AS_DIGIT(parser->buffer);
2796
2797            SKIP(parser);
2798        }
2799    }
2800
2801    /* Do the same as above, but in the opposite order. */
2802
2803    else if (IS_DIGIT(parser->buffer))
2804    {
2805        if (CHECK(parser->buffer, '0')) {
2806            yaml_parser_set_scanner_error(parser, "while scanning a block scalar",
2807                    start_mark, "found an intendation indicator equal to 0");
2808            goto error;
2809        }
2810
2811        increment = AS_DIGIT(parser->buffer);
2812
2813        SKIP(parser);
2814
2815        if (!CACHE(parser, 1)) goto error;
2816
2817        if (CHECK(parser->buffer, '+') || CHECK(parser->buffer, '-')) {
2818            chomping = CHECK(parser->buffer, '+') ? +1 : -1;
2819
2820            SKIP(parser);
2821        }
2822    }
2823
2824    /* Eat whitespaces and comments to the end of the line. */
2825
2826    if (!CACHE(parser, 1)) goto error;
2827
2828    while (IS_BLANK(parser->buffer)) {
2829        SKIP(parser);
2830        if (!CACHE(parser, 1)) goto error;
2831    }
2832
2833    if (CHECK(parser->buffer, '#')) {
2834        while (!IS_BREAKZ(parser->buffer)) {
2835            SKIP(parser);
2836            if (!CACHE(parser, 1)) goto error;
2837        }
2838    }
2839
2840    /* Check if we are at the end of the line. */
2841
2842    if (!IS_BREAKZ(parser->buffer)) {
2843        yaml_parser_set_scanner_error(parser, "while scanning a block scalar",
2844                start_mark, "did not find expected comment or line break");
2845        goto error;
2846    }
2847
2848    /* Eat a line break. */
2849
2850    if (IS_BREAK(parser->buffer)) {
2851        if (!CACHE(parser, 2)) goto error;
2852        SKIP_LINE(parser);
2853    }
2854
2855    end_mark = parser->mark;
2856
2857    /* Set the intendation level if it was specified. */
2858
2859    if (increment) {
2860        indent = parser->indent >= 0 ? parser->indent+increment : increment;
2861    }
2862
2863    /* Scan the leading line breaks and determine the indentation level if needed. */
2864
2865    if (!yaml_parser_scan_block_scalar_breaks(parser, &indent, &trailing_breaks,
2866                start_mark, &end_mark)) goto error;
2867
2868    /* Scan the block scalar content. */
2869
2870    if (!CACHE(parser, 1)) goto error;
2871
2872    while ((int)parser->mark.column == indent && !IS_Z(parser->buffer))
2873    {
2874        /*
2875         * We are at the beginning of a non-empty line.
2876         */
2877
2878        /* Is it a trailing whitespace? */
2879
2880        trailing_blank = IS_BLANK(parser->buffer);
2881
2882        /* Check if we need to fold the leading line break. */
2883
2884        if (!literal && (*leading_break.start == '\n')
2885                && !leading_blank && !trailing_blank)
2886        {
2887            /* Do we need to join the lines by space? */
2888
2889            if (*trailing_breaks.start == '\0') {
2890                if (!STRING_EXTEND(parser, string)) goto error;
2891                *(string.pointer ++) = ' ';
2892            }
2893
2894            CLEAR(parser, leading_break);
2895        }
2896        else {
2897            if (!JOIN(parser, string, leading_break)) goto error;
2898            CLEAR(parser, leading_break);
2899        }
2900
2901        /* Append the remaining line breaks. */
2902
2903        if (!JOIN(parser, string, trailing_breaks)) goto error;
2904        CLEAR(parser, trailing_breaks);
2905
2906        /* Is it a leading whitespace? */
2907
2908        leading_blank = IS_BLANK(parser->buffer);
2909
2910        /* Consume the current line. */
2911
2912        while (!IS_BREAKZ(parser->buffer)) {
2913            if (!READ(parser, string)) goto error;
2914            if (!CACHE(parser, 1)) goto error;
2915        }
2916
2917        /* Consume the line break. */
2918
2919        if (!CACHE(parser, 2)) goto error;
2920
2921        if (!READ_LINE(parser, leading_break)) goto error;
2922
2923        /* Eat the following intendation spaces and line breaks. */
2924
2925        if (!yaml_parser_scan_block_scalar_breaks(parser,
2926                    &indent, &trailing_breaks, start_mark, &end_mark)) goto error;
2927    }
2928
2929    /* Chomp the tail. */
2930
2931    if (chomping != -1) {
2932        if (!JOIN(parser, string, leading_break)) goto error;
2933    }
2934    if (chomping == 1) {
2935        if (!JOIN(parser, string, trailing_breaks)) goto error;
2936    }
2937
2938    /* Create a token. */
2939
2940    SCALAR_TOKEN_INIT(*token, string.start, string.pointer-string.start,
2941            literal ? YAML_LITERAL_SCALAR_STYLE : YAML_FOLDED_SCALAR_STYLE,
2942            start_mark, end_mark);
2943
2944    STRING_DEL(parser, leading_break);
2945    STRING_DEL(parser, trailing_breaks);
2946
2947    return 1;
2948
2949error:
2950    STRING_DEL(parser, string);
2951    STRING_DEL(parser, leading_break);
2952    STRING_DEL(parser, trailing_breaks);
2953
2954    return 0;
2955}
2956
2957/*
2958 * Scan intendation spaces and line breaks for a block scalar.  Determine the
2959 * intendation level if needed.
2960 */
2961
2962static int
2963yaml_parser_scan_block_scalar_breaks(yaml_parser_t *parser,
2964        int *indent, yaml_string_t *breaks,
2965        yaml_mark_t start_mark, yaml_mark_t *end_mark)
2966{
2967    int max_indent = 0;
2968
2969    *end_mark = parser->mark;
2970
2971    /* Eat the intendation spaces and line breaks. */
2972
2973    while (1)
2974    {
2975        /* Eat the intendation spaces. */
2976
2977        if (!CACHE(parser, 1)) return 0;
2978
2979        while ((!*indent || (int)parser->mark.column < *indent)
2980                && IS_SPACE(parser->buffer)) {
2981            SKIP(parser);
2982            if (!CACHE(parser, 1)) return 0;
2983        }
2984
2985        if ((int)parser->mark.column > max_indent)
2986            max_indent = (int)parser->mark.column;
2987
2988        /* Check for a tab character messing the intendation. */
2989
2990        if ((!*indent || (int)parser->mark.column < *indent)
2991                && IS_TAB(parser->buffer)) {
2992            return yaml_parser_set_scanner_error(parser, "while scanning a block scalar",
2993                    start_mark, "found a tab character where an intendation space is expected");
2994        }
2995
2996        /* Have we found a non-empty line? */
2997
2998        if (!IS_BREAK(parser->buffer)) break;
2999
3000        /* Consume the line break. */
3001
3002        if (!CACHE(parser, 2)) return 0;
3003        if (!READ_LINE(parser, *breaks)) return 0;
3004        *end_mark = parser->mark;
3005    }
3006
3007    /* Determine the indentation level if needed. */
3008
3009    if (!*indent) {
3010        *indent = max_indent;
3011        if (*indent < parser->indent + 1)
3012            *indent = parser->indent + 1;
3013        if (*indent < 1)
3014            *indent = 1;
3015    }
3016
3017   return 1;
3018}
3019
3020/*
3021 * Scan a quoted scalar.
3022 */
3023
3024static int
3025yaml_parser_scan_flow_scalar(yaml_parser_t *parser, yaml_token_t *token,
3026        int single)
3027{
3028    yaml_mark_t start_mark;
3029    yaml_mark_t end_mark;
3030    yaml_string_t string = NULL_STRING;
3031    yaml_string_t leading_break = NULL_STRING;
3032    yaml_string_t trailing_breaks = NULL_STRING;
3033    yaml_string_t whitespaces = NULL_STRING;
3034    int leading_blanks;
3035
3036    if (!STRING_INIT(parser, string, INITIAL_STRING_SIZE)) goto error;
3037    if (!STRING_INIT(parser, leading_break, INITIAL_STRING_SIZE)) goto error;
3038    if (!STRING_INIT(parser, trailing_breaks, INITIAL_STRING_SIZE)) goto error;
3039    if (!STRING_INIT(parser, whitespaces, INITIAL_STRING_SIZE)) goto error;
3040
3041    /* Eat the left quote. */
3042
3043    start_mark = parser->mark;
3044
3045    SKIP(parser);
3046
3047    /* Consume the content of the quoted scalar. */
3048
3049    while (1)
3050    {
3051        /* Check that there are no document indicators at the beginning of the line. */
3052
3053        if (!CACHE(parser, 4)) goto error;
3054
3055        if (parser->mark.column == 0 &&
3056            ((CHECK_AT(parser->buffer, '-', 0) &&
3057              CHECK_AT(parser->buffer, '-', 1) &&
3058              CHECK_AT(parser->buffer, '-', 2)) ||
3059             (CHECK_AT(parser->buffer, '.', 0) &&
3060              CHECK_AT(parser->buffer, '.', 1) &&
3061              CHECK_AT(parser->buffer, '.', 2))) &&
3062            IS_BLANKZ_AT(parser->buffer, 3))
3063        {
3064            yaml_parser_set_scanner_error(parser, "while scanning a quoted scalar",
3065                    start_mark, "found unexpected document indicator");
3066            goto error;
3067        }
3068
3069        /* Check for EOF. */
3070
3071        if (IS_Z(parser->buffer)) {
3072            yaml_parser_set_scanner_error(parser, "while scanning a quoted scalar",
3073                    start_mark, "found unexpected end of stream");
3074            goto error;
3075        }
3076
3077        /* Consume non-blank characters. */
3078
3079        if (!CACHE(parser, 2)) goto error;
3080
3081        leading_blanks = 0;
3082
3083        while (!IS_BLANKZ(parser->buffer))
3084        {
3085            /* Check for an escaped single quote. */
3086
3087            if (single && CHECK_AT(parser->buffer, '\'', 0)
3088                    && CHECK_AT(parser->buffer, '\'', 1))
3089            {
3090                if (!STRING_EXTEND(parser, string)) goto error;
3091                *(string.pointer++) = '\'';
3092                SKIP(parser);
3093                SKIP(parser);
3094            }
3095
3096            /* Check for the right quote. */
3097
3098            else if (CHECK(parser->buffer, single ? '\'' : '"'))
3099            {
3100                break;
3101            }
3102
3103            /* Check for an escaped line break. */
3104
3105            else if (!single && CHECK(parser->buffer, '\\')
3106                    && IS_BREAK_AT(parser->buffer, 1))
3107            {
3108                if (!CACHE(parser, 3)) goto error;
3109                SKIP(parser);
3110                SKIP_LINE(parser);
3111                leading_blanks = 1;
3112                break;
3113            }
3114
3115            /* Check for an escape sequence. */
3116
3117            else if (!single && CHECK(parser->buffer, '\\'))
3118            {
3119                size_t code_length = 0;
3120
3121                if (!STRING_EXTEND(parser, string)) goto error;
3122
3123                /* Check the escape character. */
3124
3125                switch (parser->buffer.pointer[1])
3126                {
3127                    case '0':
3128                        *(string.pointer++) = '\0';
3129                        break;
3130
3131                    case 'a':
3132                        *(string.pointer++) = '\x07';
3133                        break;
3134
3135                    case 'b':
3136                        *(string.pointer++) = '\x08';
3137                        break;
3138
3139                    case 't':
3140                    case '\t':
3141                        *(string.pointer++) = '\x09';
3142                        break;
3143
3144                    case 'n':
3145                        *(string.pointer++) = '\x0A';
3146                        break;
3147
3148                    case 'v':
3149                        *(string.pointer++) = '\x0B';
3150                        break;
3151
3152                    case 'f':
3153                        *(string.pointer++) = '\x0C';
3154                        break;
3155
3156                    case 'r':
3157                        *(string.pointer++) = '\x0D';
3158                        break;
3159
3160                    case 'e':
3161                        *(string.pointer++) = '\x1B';
3162                        break;
3163
3164                    case ' ':
3165                        *(string.pointer++) = '\x20';
3166                        break;
3167
3168                    case '"':
3169                        *(string.pointer++) = '"';
3170                        break;
3171
3172                    case '\'':
3173                        *(string.pointer++) = '\'';
3174                        break;
3175
3176                    case '\\':
3177                        *(string.pointer++) = '\\';
3178                        break;
3179
3180                    case 'N':   /* NEL (#x85) */
3181                        *(string.pointer++) = '\xC2';
3182                        *(string.pointer++) = '\x85';
3183                        break;
3184
3185                    case '_':   /* #xA0 */
3186                        *(string.pointer++) = '\xC2';
3187                        *(string.pointer++) = '\xA0';
3188                        break;
3189
3190                    case 'L':   /* LS (#x2028) */
3191                        *(string.pointer++) = '\xE2';
3192                        *(string.pointer++) = '\x80';
3193                        *(string.pointer++) = '\xA8';
3194                        break;
3195
3196                    case 'P':   /* PS (#x2029) */
3197                        *(string.pointer++) = '\xE2';
3198                        *(string.pointer++) = '\x80';
3199                        *(string.pointer++) = '\xA9';
3200                        break;
3201
3202                    case 'x':
3203                        code_length = 2;
3204                        break;
3205
3206                    case 'u':
3207                        code_length = 4;
3208                        break;
3209
3210                    case 'U':
3211                        code_length = 8;
3212                        break;
3213
3214                    default:
3215                        yaml_parser_set_scanner_error(parser, "while parsing a quoted scalar",
3216                                start_mark, "found unknown escape character");
3217                        goto error;
3218                }
3219
3220                SKIP(parser);
3221                SKIP(parser);
3222
3223                /* Consume an arbitrary escape code. */
3224
3225                if (code_length)
3226                {
3227                    unsigned int value = 0;
3228                    size_t k;
3229
3230                    /* Scan the character value. */
3231
3232                    if (!CACHE(parser, code_length)) goto error;
3233
3234                    for (k = 0; k < code_length; k ++) {
3235                        if (!IS_HEX_AT(parser->buffer, k)) {
3236                            yaml_parser_set_scanner_error(parser, "while parsing a quoted scalar",
3237                                    start_mark, "did not find expected hexdecimal number");
3238                            goto error;
3239                        }
3240                        value = (value << 4) + AS_HEX_AT(parser->buffer, k);
3241                    }
3242
3243                    /* Check the value and write the character. */
3244
3245                    if ((value >= 0xD800 && value <= 0xDFFF) || value > 0x10FFFF) {
3246                        yaml_parser_set_scanner_error(parser, "while parsing a quoted scalar",
3247                                start_mark, "found invalid Unicode character escape code");
3248                        goto error;
3249                    }
3250
3251                    if (value <= 0x7F) {
3252                        *(string.pointer++) = value;
3253                    }
3254                    else if (value <= 0x7FF) {
3255                        *(string.pointer++) = 0xC0 + (value >> 6);
3256                        *(string.pointer++) = 0x80 + (value & 0x3F);
3257                    }
3258                    else if (value <= 0xFFFF) {
3259                        *(string.pointer++) = 0xE0 + (value >> 12);
3260                        *(string.pointer++) = 0x80 + ((value >> 6) & 0x3F);
3261                        *(string.pointer++) = 0x80 + (value & 0x3F);
3262                    }
3263                    else {
3264                        *(string.pointer++) = 0xF0 + (value >> 18);
3265                        *(string.pointer++) = 0x80 + ((value >> 12) & 0x3F);
3266                        *(string.pointer++) = 0x80 + ((value >> 6) & 0x3F);
3267                        *(string.pointer++) = 0x80 + (value & 0x3F);
3268                    }
3269
3270                    /* Advance the pointer. */
3271
3272                    for (k = 0; k < code_length; k ++) {
3273                        SKIP(parser);
3274                    }
3275                }
3276            }
3277
3278            else
3279            {
3280                /* It is a non-escaped non-blank character. */
3281
3282                if (!READ(parser, string)) goto error;
3283            }
3284
3285            if (!CACHE(parser, 2)) goto error;
3286        }
3287
3288        /* Check if we are at the end of the scalar. */
3289
3290        if (CHECK(parser->buffer, single ? '\'' : '"'))
3291            break;
3292
3293        /* Consume blank characters. */
3294
3295        if (!CACHE(parser, 1)) goto error;
3296
3297        while (IS_BLANK(parser->buffer) || IS_BREAK(parser->buffer))
3298        {
3299            if (IS_BLANK(parser->buffer))
3300            {
3301                /* Consume a space or a tab character. */
3302
3303                if (!leading_blanks) {
3304                    if (!READ(parser, whitespaces)) goto error;
3305                }
3306                else {
3307                    SKIP(parser);
3308                }
3309            }
3310            else
3311            {
3312                if (!CACHE(parser, 2)) goto error;
3313
3314                /* Check if it is a first line break. */
3315
3316                if (!leading_blanks)
3317                {
3318                    CLEAR(parser, whitespaces);
3319                    if (!READ_LINE(parser, leading_break)) goto error;
3320                    leading_blanks = 1;
3321                }
3322                else
3323                {
3324                    if (!READ_LINE(parser, trailing_breaks)) goto error;
3325                }
3326            }
3327            if (!CACHE(parser, 1)) goto error;
3328        }
3329
3330        /* Join the whitespaces or fold line breaks. */
3331
3332        if (leading_blanks)
3333        {
3334            /* Do we need to fold line breaks? */
3335
3336            if (leading_break.start[0] == '\n') {
3337                if (trailing_breaks.start[0] == '\0') {
3338                    if (!STRING_EXTEND(parser, string)) goto error;
3339                    *(string.pointer++) = ' ';
3340                }
3341                else {
3342                    if (!JOIN(parser, string, trailing_breaks)) goto error;
3343                    CLEAR(parser, trailing_breaks);
3344                }
3345                CLEAR(parser, leading_break);
3346            }
3347            else {
3348                if (!JOIN(parser, string, leading_break)) goto error;
3349                if (!JOIN(parser, string, trailing_breaks)) goto error;
3350                CLEAR(parser, leading_break);
3351                CLEAR(parser, trailing_breaks);
3352            }
3353        }
3354        else
3355        {
3356            if (!JOIN(parser, string, whitespaces)) goto error;
3357            CLEAR(parser, whitespaces);
3358        }
3359    }
3360
3361    /* Eat the right quote. */
3362
3363    SKIP(parser);
3364
3365    end_mark = parser->mark;
3366
3367    /* Create a token. */
3368
3369    SCALAR_TOKEN_INIT(*token, string.start, string.pointer-string.start,
3370            single ? YAML_SINGLE_QUOTED_SCALAR_STYLE : YAML_DOUBLE_QUOTED_SCALAR_STYLE,
3371            start_mark, end_mark);
3372
3373    STRING_DEL(parser, leading_break);
3374    STRING_DEL(parser, trailing_breaks);
3375    STRING_DEL(parser, whitespaces);
3376
3377    return 1;
3378
3379error:
3380    STRING_DEL(parser, string);
3381    STRING_DEL(parser, leading_break);
3382    STRING_DEL(parser, trailing_breaks);
3383    STRING_DEL(parser, whitespaces);
3384
3385    return 0;
3386}
3387
3388/*
3389 * Scan a plain scalar.
3390 */
3391
3392static int
3393yaml_parser_scan_plain_scalar(yaml_parser_t *parser, yaml_token_t *token)
3394{
3395    yaml_mark_t start_mark;
3396    yaml_mark_t end_mark;
3397    yaml_string_t string = NULL_STRING;
3398    yaml_string_t leading_break = NULL_STRING;
3399    yaml_string_t trailing_breaks = NULL_STRING;
3400    yaml_string_t whitespaces = NULL_STRING;
3401    int leading_blanks = 0;
3402    int indent = parser->indent+1;
3403
3404    if (!STRING_INIT(parser, string, INITIAL_STRING_SIZE)) goto error;
3405    if (!STRING_INIT(parser, leading_break, INITIAL_STRING_SIZE)) goto error;
3406    if (!STRING_INIT(parser, trailing_breaks, INITIAL_STRING_SIZE)) goto error;
3407    if (!STRING_INIT(parser, whitespaces, INITIAL_STRING_SIZE)) goto error;
3408
3409    start_mark = end_mark = parser->mark;
3410
3411    /* Consume the content of the plain scalar. */
3412
3413    while (1)
3414    {
3415        /* Check for a document indicator. */
3416
3417        if (!CACHE(parser, 4)) goto error;
3418
3419        if (parser->mark.column == 0 &&
3420            ((CHECK_AT(parser->buffer, '-', 0) &&
3421              CHECK_AT(parser->buffer, '-', 1) &&
3422              CHECK_AT(parser->buffer, '-', 2)) ||
3423             (CHECK_AT(parser->buffer, '.', 0) &&
3424              CHECK_AT(parser->buffer, '.', 1) &&
3425              CHECK_AT(parser->buffer, '.', 2))) &&
3426            IS_BLANKZ_AT(parser->buffer, 3)) break;
3427
3428        /* Check for a comment. */
3429
3430        if (CHECK(parser->buffer, '#'))
3431            break;
3432
3433        /* Consume non-blank characters. */
3434
3435        while (!IS_BLANKZ(parser->buffer))
3436        {
3437            /* Check for 'x:x' in the flow context. TODO: Fix the test "spec-08-13". */
3438
3439            if (parser->flow_level
3440                    && CHECK(parser->buffer, ':')
3441                    && !IS_BLANKZ_AT(parser->buffer, 1)) {
3442                yaml_parser_set_scanner_error(parser, "while scanning a plain scalar",
3443                        start_mark, "found unexpected ':'");
3444                goto error;
3445            }
3446
3447            /* Check for indicators that may end a plain scalar. */
3448
3449            if ((CHECK(parser->buffer, ':') && IS_BLANKZ_AT(parser->buffer, 1))
3450                    || (parser->flow_level &&
3451                        (CHECK(parser->buffer, ',') || CHECK(parser->buffer, ':')
3452                         || CHECK(parser->buffer, '?') || CHECK(parser->buffer, '[')
3453                         || CHECK(parser->buffer, ']') || CHECK(parser->buffer, '{')
3454                         || CHECK(parser->buffer, '}'))))
3455                break;
3456
3457            /* Check if we need to join whitespaces and breaks. */
3458
3459            if (leading_blanks || whitespaces.start != whitespaces.pointer)
3460            {
3461                if (leading_blanks)
3462                {
3463                    /* Do we need to fold line breaks? */
3464
3465                    if (leading_break.start[0] == '\n') {
3466                        if (trailing_breaks.start[0] == '\0') {
3467                            if (!STRING_EXTEND(parser, string)) goto error;
3468                            *(string.pointer++) = ' ';
3469                        }
3470                        else {
3471                            if (!JOIN(parser, string, trailing_breaks)) goto error;
3472                            CLEAR(parser, trailing_breaks);
3473                        }
3474                        CLEAR(parser, leading_break);
3475                    }
3476                    else {
3477                        if (!JOIN(parser, string, leading_break)) goto error;
3478                        if (!JOIN(parser, string, trailing_breaks)) goto error;
3479                        CLEAR(parser, leading_break);
3480                        CLEAR(parser, trailing_breaks);
3481                    }
3482
3483                    leading_blanks = 0;
3484                }
3485                else
3486                {
3487                    if (!JOIN(parser, string, whitespaces)) goto error;
3488                    CLEAR(parser, whitespaces);
3489                }
3490            }
3491
3492            /* Copy the character. */
3493
3494            if (!READ(parser, string)) goto error;
3495
3496            end_mark = parser->mark;
3497
3498            if (!CACHE(parser, 2)) goto error;
3499        }
3500
3501        /* Is it the end? */
3502
3503        if (!(IS_BLANK(parser->buffer) || IS_BREAK(parser->buffer)))
3504            break;
3505
3506        /* Consume blank characters. */
3507
3508        if (!CACHE(parser, 1)) goto error;
3509
3510        while (IS_BLANK(parser->buffer) || IS_BREAK(parser->buffer))
3511        {
3512            if (IS_BLANK(parser->buffer))
3513            {
3514                /* Check for tab character that abuse intendation. */
3515
3516                if (leading_blanks && (int)parser->mark.column < indent
3517                        && IS_TAB(parser->buffer)) {
3518                    yaml_parser_set_scanner_error(parser, "while scanning a plain scalar",
3519                            start_mark, "found a tab character that violate intendation");
3520                    goto error;
3521                }
3522
3523                /* Consume a space or a tab character. */
3524
3525                if (!leading_blanks) {
3526                    if (!READ(parser, whitespaces)) goto error;
3527                }
3528                else {
3529                    SKIP(parser);
3530                }
3531            }
3532            else
3533            {
3534                if (!CACHE(parser, 2)) goto error;
3535
3536                /* Check if it is a first line break. */
3537
3538                if (!leading_blanks)
3539                {
3540                    CLEAR(parser, whitespaces);
3541                    if (!READ_LINE(parser, leading_break)) goto error;
3542                    leading_blanks = 1;
3543                }
3544                else
3545                {
3546                    if (!READ_LINE(parser, trailing_breaks)) goto error;
3547                }
3548            }
3549            if (!CACHE(parser, 1)) goto error;
3550        }
3551
3552        /* Check intendation level. */
3553
3554        if (!parser->flow_level && (int)parser->mark.column < indent)
3555            break;
3556    }
3557
3558    /* Create a token. */
3559
3560    SCALAR_TOKEN_INIT(*token, string.start, string.pointer-string.start,
3561            YAML_PLAIN_SCALAR_STYLE, start_mark, end_mark);
3562
3563    /* Note that we change the 'simple_key_allowed' flag. */
3564
3565    if (leading_blanks) {
3566        parser->simple_key_allowed = 1;
3567    }
3568
3569    STRING_DEL(parser, leading_break);
3570    STRING_DEL(parser, trailing_breaks);
3571    STRING_DEL(parser, whitespaces);
3572
3573    return 1;
3574
3575error:
3576    STRING_DEL(parser, string);
3577    STRING_DEL(parser, leading_break);
3578    STRING_DEL(parser, trailing_breaks);
3579    STRING_DEL(parser, whitespaces);
3580
3581    return 0;
3582}
3583
3584