src/emitter.c

   1
   2 #include "yaml_private.h"
   3
   4 /*
   5  * Flush the buffer if needed.
   6  */
   7
   8 #define FLUSH(emitter)                                                          \
   9     ((emitter->buffer.pointer+5 < emitter->buffer.end)                          \
  10      || yaml_emitter_flush(emitter))
  11
  12 /*
  13  * Put a character to the output buffer.
  14  */
  15
  16 #define PUT(emitter,value)                                                      \
  17     (FLUSH(emitter)                                                             \
  18      && (*(emitter->buffer.pointer++) = (yaml_char_t)(value),                   \
  19          emitter->column ++,                                                    \
  20          1))
  21
  22 /*
  23  * Put a line break to the output buffer.
  24  */
  25
  26 #define PUT_BREAK(emitter)                                                      \
  27     (FLUSH(emitter)                                                             \
  28      && ((emitter->line_break == YAML_CR_BREAK ?                                \
  29              (*(emitter->buffer.pointer++) = (yaml_char_t) '\r') :              \
  30           emitter->line_break == YAML_LN_BREAK ?                                \
  31              (*(emitter->buffer.pointer++) = (yaml_char_t) '\n') :              \
  32           emitter->line_break == YAML_CRLN_BREAK ?                              \
  33              (*(emitter->buffer.pointer++) = (yaml_char_t) '\r',                \
  34               *(emitter->buffer.pointer++) = (yaml_char_t) '\n') : 0),          \
  35          emitter->column = 0,                                                   \
  36          emitter->line ++,                                                      \
  37          1))
  38
  39 /*
  40  * Copy a character from a string into buffer.
  41  */
  42
  43 #define WRITE(emitter,string)                                                   \
  44     (FLUSH(emitter)                                                             \
  45      && (COPY(emitter->buffer,string),                                          \
  46          emitter->column ++,                                                    \
  47          1))
  48
  49 /*
  50  * Copy a line break character from a string into buffer.
  51  */
  52
  53 #define WRITE_BREAK(emitter,string)                                             \
  54     (FLUSH(emitter)                                                             \
  55      && (CHECK(string,'\n') ?                                                   \
  56          (PUT_BREAK(emitter),                                                   \
  57           string.pointer ++,                                                    \
  58           1) :                                                                  \
  59          (COPY(emitter->buffer,string),                                         \
  60           emitter->column = 0,                                                  \
  61           emitter->line ++,                                                     \
  62           1)))
  63
  64 /*
  65  * API functions.
  66  */
  67
  68 YAML_DECLARE(int)
  69 yaml_emitter_emit(yaml_emitter_t *emitter, yaml_event_t *event);
  70
  71 /*
  72  * Utility functions.
  73  */
  74
  75 static int
  76 yaml_emitter_set_emitter_error(yaml_emitter_t *emitter, const char *problem);
  77
  78 static int
  79 yaml_emitter_need_more_events(yaml_emitter_t *emitter);
  80
  81 static int
  82 yaml_emitter_append_tag_directive(yaml_emitter_t *emitter,
  83         yaml_tag_directive_t value, int allow_duplicates);
  84
  85 static int
  86 yaml_emitter_increase_indent(yaml_emitter_t *emitter,
  87         int flow, int indentless);
  88
  89 /*
  90  * State functions.
  91  */
  92
  93 static int
  94 yaml_emitter_state_machine(yaml_emitter_t *emitter, yaml_event_t *event);
  95
  96 static int
  97 yaml_emitter_emit_stream_start(yaml_emitter_t *emitter,
  98         yaml_event_t *event);
  99
 100 static int
 101 yaml_emitter_emit_document_start(yaml_emitter_t *emitter,
 102         yaml_event_t *event, int first);
 103
 104 static int
 105 yaml_emitter_emit_document_content(yaml_emitter_t *emitter,
 106         yaml_event_t *event);
 107
 108 static int
 109 yaml_emitter_emit_document_end(yaml_emitter_t *emitter,
 110         yaml_event_t *event);
 111
 112 static int
 113 yaml_emitter_emit_flow_sequence_item(yaml_emitter_t *emitter,
 114         yaml_event_t *event, int first);
 115
 116 static int
 117 yaml_emitter_emit_flow_mapping_key(yaml_emitter_t *emitter,
 118         yaml_event_t *event, int first);
 119
 120 static int
 121 yaml_emitter_emit_flow_mapping_value(yaml_emitter_t *emitter,
 122         yaml_event_t *event, int simple);
 123
 124 static int
 125 yaml_emitter_emit_block_sequence_item(yaml_emitter_t *emitter,
 126         yaml_event_t *event, int first);
 127
 128 static int
 129 yaml_emitter_emit_block_mapping_key(yaml_emitter_t *emitter,
 130         yaml_event_t *event, int first);
 131
 132 static int
 133 yaml_emitter_emit_block_mapping_value(yaml_emitter_t *emitter,
 134         yaml_event_t *event, int simple);
 135
 136 static int
 137 yaml_emitter_emit_node(yaml_emitter_t *emitter, yaml_event_t *event,
 138         int root, int sequence, int mapping, int simple_key);
 139
 140 static int
 141 yaml_emitter_emit_alias(yaml_emitter_t *emitter, yaml_event_t *event);
 142
 143 static int
 144 yaml_emitter_emit_scalar(yaml_emitter_t *emitter, yaml_event_t *event);
 145
 146 static int
 147 yaml_emitter_emit_sequence_start(yaml_emitter_t *emitter, yaml_event_t *event);
 148
 149 static int
 150 yaml_emitter_emit_mapping_start(yaml_emitter_t *emitter, yaml_event_t *event);
 151
 152 /*
 153  * Checkers.
 154  */
 155
 156 static int
 157 yaml_emitter_check_empty_document(yaml_emitter_t *emitter);
 158
 159 static int
 160 yaml_emitter_check_empty_sequence(yaml_emitter_t *emitter);
 161
 162 static int
 163 yaml_emitter_check_empty_mapping(yaml_emitter_t *emitter);
 164
 165 static int
 166 yaml_emitter_check_simple_key(yaml_emitter_t *emitter);
 167
 168 static int
 169 yaml_emitter_select_scalar_style(yaml_emitter_t *emitter, yaml_event_t *event);
 170
 171 /*
 172  * Processors.
 173  */
 174
 175 static int
 176 yaml_emitter_process_anchor(yaml_emitter_t *emitter);
 177
 178 static int
 179 yaml_emitter_process_tag(yaml_emitter_t *emitter);
 180
 181 static int
 182 yaml_emitter_process_scalar(yaml_emitter_t *emitter);
 183
 184 /*
 185  * Analyzers.
 186  */
 187
 188 static int
 189 yaml_emitter_analyze_version_directive(yaml_emitter_t *emitter,
 190         yaml_version_directive_t version_directive);
 191
 192 static int
 193 yaml_emitter_analyze_tag_directive(yaml_emitter_t *emitter,
 194         yaml_tag_directive_t tag_directive);
 195
 196 static int
 197 yaml_emitter_analyze_anchor(yaml_emitter_t *emitter,
 198         yaml_char_t *anchor, int alias);
 199
 200 static int
 201 yaml_emitter_analyze_tag(yaml_emitter_t *emitter,
 202         yaml_char_t *tag);
 203
 204 static int
 205 yaml_emitter_analyze_scalar(yaml_emitter_t *emitter,
 206         yaml_char_t *value, size_t length);
 207
 208 static int
 209 yaml_emitter_analyze_event(yaml_emitter_t *emitter,
 210         yaml_event_t *event);
 211
 212 /*
 213  * Writers.
 214  */
 215
 216 static int
 217 yaml_emitter_write_bom(yaml_emitter_t *emitter);
 218
 219 static int
 220 yaml_emitter_write_indent(yaml_emitter_t *emitter);
 221
 222 static int
 223 yaml_emitter_write_indicator(yaml_emitter_t *emitter,
 224         char *indicator, int need_whitespace,
 225         int is_whitespace, int is_indention);
 226
 227 static int
 228 yaml_emitter_write_anchor(yaml_emitter_t *emitter,
 229         yaml_char_t *value, size_t length);
 230
 231 static int
 232 yaml_emitter_write_tag_handle(yaml_emitter_t *emitter,
 233         yaml_char_t *value, size_t length);
 234
 235 static int
 236 yaml_emitter_write_tag_content(yaml_emitter_t *emitter,
 237         yaml_char_t *value, size_t length, int need_whitespace);
 238
 239 static int
 240 yaml_emitter_write_plain_scalar(yaml_emitter_t *emitter,
 241         yaml_char_t *value, size_t length, int allow_breaks);
 242
 243 static int
 244 yaml_emitter_write_single_quoted_scalar(yaml_emitter_t *emitter,
 245         yaml_char_t *value, size_t length, int allow_breaks);
 246
 247 static int
 248 yaml_emitter_write_double_quoted_scalar(yaml_emitter_t *emitter,
 249         yaml_char_t *value, size_t length, int allow_breaks);
 250
 251 static int
 252 yaml_emitter_write_block_scalar_hints(yaml_emitter_t *emitter,
 253         yaml_string_t string);
 254
 255 static int
 256 yaml_emitter_write_literal_scalar(yaml_emitter_t *emitter,
 257         yaml_char_t *value, size_t length);
 258
 259 static int
 260 yaml_emitter_write_folded_scalar(yaml_emitter_t *emitter,
 261         yaml_char_t *value, size_t length);
 262
 263 /*
 264  * Set an emitter error and return 0.
 265  */
 266
 267 static int
 268 yaml_emitter_set_emitter_error(yaml_emitter_t *emitter, const char *problem)
 269 {
 270     emitter->error = YAML_EMITTER_ERROR;
 271     emitter->problem = problem;
 272
 273     return 0;
 274 }
 275
 276 /*
 277  * Emit an event.
 278  */
 279
 280 YAML_DECLARE(int)
 281 yaml_emitter_emit(yaml_emitter_t *emitter, yaml_event_t *event)
 282 {
 283     if (!ENQUEUE(emitter, emitter->events, *event)) {
 284         yaml_event_delete(event);
 285         return 0;
 286     }
 287
 288     while (!yaml_emitter_need_more_events(emitter)) {
 289         if (!yaml_emitter_analyze_event(emitter, emitter->events.head))
 290             return 0;
 291         if (!yaml_emitter_state_machine(emitter, emitter->events.head))
 292             return 0;
 293         yaml_event_delete(&DEQUEUE(emitter, emitter->events));
 294     }
 295
 296     return 1;
 297 }
 298
 299 /*
 300  * Check if we need to accumulate more events before emitting.
 301  *
 302  * We accumulate extra
 303  *  - 1 event for DOCUMENT-START
 304  *  - 2 events for SEQUENCE-START
 305  *  - 3 events for MAPPING-START
 306  */
 307
 308 static int
 309 yaml_emitter_need_more_events(yaml_emitter_t *emitter)
 310 {
 311     int level = 0;
 312     int accumulate = 0;
 313     yaml_event_t *event;
 314
 315     if (QUEUE_EMPTY(emitter, emitter->events))
 316         return 1;
 317
 318     switch (emitter->events.head->type) {
 319         case YAML_DOCUMENT_START_EVENT:
 320             accumulate = 1;
 321             break;
 322         case YAML_SEQUENCE_START_EVENT:
 323             accumulate = 2;
 324             break;
 325         case YAML_MAPPING_START_EVENT:
 326             accumulate = 3;
 327             break;
 328         default:
 329             return 0;
 330     }
 331
 332     if (emitter->events.tail - emitter->events.head > accumulate)
 333         return 0;
 334
 335     for (event = emitter->events.head; event != emitter->events.tail; event ++) {
 336         switch (event->type) {
 337             case YAML_STREAM_START_EVENT:
 338             case YAML_DOCUMENT_START_EVENT:
 339             case YAML_SEQUENCE_START_EVENT:
 340             case YAML_MAPPING_START_EVENT:
 341                 level += 1;
 342                 break;
 343             case YAML_STREAM_END_EVENT:
 344             case YAML_DOCUMENT_END_EVENT:
 345             case YAML_SEQUENCE_END_EVENT:
 346             case YAML_MAPPING_END_EVENT:
 347                 level -= 1;
 348                 break;
 349             default:
 350                 break;
 351         }
 352         if (!level)
 353             return 0;
 354     }
 355
 356     return 1;
 357 }
 358
 359 /*
 360  * Append a directive to the directives stack.
 361  */
 362
 363 static int
 364 yaml_emitter_append_tag_directive(yaml_emitter_t *emitter,
 365         yaml_tag_directive_t value, int allow_duplicates)
 366 {
 367     yaml_tag_directive_t *tag_directive;
 368     yaml_tag_directive_t copy = { NULL, NULL };
 369
 370     for (tag_directive = emitter->tag_directives.start;
 371             tag_directive != emitter->tag_directives.top; tag_directive ++) {
 372         if (strcmp((char *)value.handle, (char *)tag_directive->handle) == 0) {
 373             if (allow_duplicates)
 374                 return 1;
 375             return yaml_emitter_set_emitter_error(emitter,
 376                     "duplicate %TAG directive");
 377         }
 378     }
 379
 380     copy.handle = yaml_strdup(value.handle);
 381     copy.prefix = yaml_strdup(value.prefix);
 382     if (!copy.handle || !copy.prefix) {
 383         emitter->error = YAML_MEMORY_ERROR;
 384         goto error;
 385     }
 386
 387     if (!PUSH(emitter, emitter->tag_directives, copy))
 388         goto error;
 389
 390     return 1;
 391
 392 error:
 393     yaml_free(copy.handle);
 394     yaml_free(copy.prefix);
 395     return 0;
 396 }
 397
 398 /*
 399  * Increase the indentation level.
 400  */
 401
 402 static int
 403 yaml_emitter_increase_indent(yaml_emitter_t *emitter,
 404         int flow, int indentless)
 405 {
 406     if (!PUSH(emitter, emitter->indents, emitter->indent))
 407         return 0;
 408
 409     if (emitter->indent < 0) {
 410         emitter->indent = flow ? emitter->best_indent : 0;
 411     }
 412     else if (!indentless) {
 413         emitter->indent += emitter->best_indent;
 414     }
 415
 416     return 1;
 417 }
 418
 419 /*
 420  * State dispatcher.
 421  */
 422
 423 static int
 424 yaml_emitter_state_machine(yaml_emitter_t *emitter, yaml_event_t *event)
 425 {
 426     switch (emitter->state)
 427     {
 428         case YAML_EMIT_STREAM_START_STATE:
 429             return yaml_emitter_emit_stream_start(emitter, event);
 430
 431         case YAML_EMIT_FIRST_DOCUMENT_START_STATE:
 432             return yaml_emitter_emit_document_start(emitter, event, 1);
 433
 434         case YAML_EMIT_DOCUMENT_START_STATE:
 435             return yaml_emitter_emit_document_start(emitter, event, 0);
 436
 437         case YAML_EMIT_DOCUMENT_CONTENT_STATE:
 438             return yaml_emitter_emit_document_content(emitter, event);
 439
 440         case YAML_EMIT_DOCUMENT_END_STATE:
 441             return yaml_emitter_emit_document_end(emitter, event);
 442
 443         case YAML_EMIT_FLOW_SEQUENCE_FIRST_ITEM_STATE:
 444             return yaml_emitter_emit_flow_sequence_item(emitter, event, 1);
 445
 446         case YAML_EMIT_FLOW_SEQUENCE_ITEM_STATE:
 447             return yaml_emitter_emit_flow_sequence_item(emitter, event, 0);
 448
 449         case YAML_EMIT_FLOW_MAPPING_FIRST_KEY_STATE:
 450             return yaml_emitter_emit_flow_mapping_key(emitter, event, 1);
 451
 452         case YAML_EMIT_FLOW_MAPPING_KEY_STATE:
 453             return yaml_emitter_emit_flow_mapping_key(emitter, event, 0);
 454
 455         case YAML_EMIT_FLOW_MAPPING_SIMPLE_VALUE_STATE:
 456             return yaml_emitter_emit_flow_mapping_value(emitter, event, 1);
 457
 458         case YAML_EMIT_FLOW_MAPPING_VALUE_STATE:
 459             return yaml_emitter_emit_flow_mapping_value(emitter, event, 0);
 460
 461         case YAML_EMIT_BLOCK_SEQUENCE_FIRST_ITEM_STATE:
 462             return yaml_emitter_emit_block_sequence_item(emitter, event, 1);
 463
 464         case YAML_EMIT_BLOCK_SEQUENCE_ITEM_STATE:
 465             return yaml_emitter_emit_block_sequence_item(emitter, event, 0);
 466
 467         case YAML_EMIT_BLOCK_MAPPING_FIRST_KEY_STATE:
 468             return yaml_emitter_emit_block_mapping_key(emitter, event, 1);
 469
 470         case YAML_EMIT_BLOCK_MAPPING_KEY_STATE:
 471             return yaml_emitter_emit_block_mapping_key(emitter, event, 0);
 472
 473         case YAML_EMIT_BLOCK_MAPPING_SIMPLE_VALUE_STATE:
 474             return yaml_emitter_emit_block_mapping_value(emitter, event, 1);
 475
 476         case YAML_EMIT_BLOCK_MAPPING_VALUE_STATE:
 477             return yaml_emitter_emit_block_mapping_value(emitter, event, 0);
 478
 479         case YAML_EMIT_END_STATE:
 480             return yaml_emitter_set_emitter_error(emitter,
 481                     "expected nothing after STREAM-END");
 482
 483         default:
 484             assert(1);      /* Invalid state. */
 485     }
 486
 487     return 0;
 488 }
 489
 490 /*
 491  * Expect STREAM-START.
 492  */
 493
 494 static int
 495 yaml_emitter_emit_stream_start(yaml_emitter_t *emitter,
 496         yaml_event_t *event)
 497 {
 498     if (event->type == YAML_STREAM_START_EVENT)
 499     {
 500         if (!emitter->encoding) {
 501             emitter->encoding = event->data.stream_start.encoding;
 502         }
 503
 504         if (!emitter->encoding) {
 505             emitter->encoding = YAML_UTF8_ENCODING;
 506         }
 507
 508         if (emitter->best_indent < 2 || emitter->best_indent > 9) {
 509             emitter->best_indent  = 2;
 510         }
 511
 512         if (emitter->best_width >= 0
 513                 && emitter->best_width <= emitter->best_indent*2) {
 514             emitter->best_width = 80;
 515         }
 516
 517         if (emitter->best_width < 0) {
 518             emitter->best_width = INT_MAX;
 519         }
 520
 521         if (!emitter->line_break) {
 522             emitter->line_break = YAML_LN_BREAK;
 523         }
 524
 525         emitter->indent = -1;
 526
 527         emitter->line = 0;
 528         emitter->column = 0;
 529         emitter->whitespace = 1;
 530         emitter->indention = 1;
 531
 532         if (emitter->encoding != YAML_UTF8_ENCODING) {
 533             if (!yaml_emitter_write_bom(emitter))
 534                 return 0;
 535         }
 536
 537         emitter->state = YAML_EMIT_FIRST_DOCUMENT_START_STATE;
 538
 539         return 1;
 540     }
 541
 542     return yaml_emitter_set_emitter_error(emitter,
 543             "expected STREAM-START");
 544 }
 545
 546 /*
 547  * Expect DOCUMENT-START or STREAM-END.
 548  */
 549
 550 static int
 551 yaml_emitter_emit_document_start(yaml_emitter_t *emitter,
 552         yaml_event_t *event, int first)
 553 {
 554     if (event->type == YAML_DOCUMENT_START_EVENT)
 555     {
 556         yaml_tag_directive_t default_tag_directives[] = {
 557             {(yaml_char_t *)"!", (yaml_char_t *)"!"},
 558             {(yaml_char_t *)"!!", (yaml_char_t *)"tag:yaml.org,2002:"},
 559             {NULL, NULL}
 560         };
 561         yaml_tag_directive_t *tag_directive;
 562         int implicit;
 563
 564         if (event->data.document_start.version_directive) {
 565             if (!yaml_emitter_analyze_version_directive(emitter,
 566                         *event->data.document_start.version_directive))
 567                 return 0;
 568         }
 569
 570         for (tag_directive = event->data.document_start.tag_directives.start;
 571                 tag_directive != event->data.document_start.tag_directives.end;
 572                 tag_directive ++) {
 573             if (!yaml_emitter_analyze_tag_directive(emitter, *tag_directive))
 574                 return 0;
 575             if (!yaml_emitter_append_tag_directive(emitter, *tag_directive, 0))
 576                 return 0;
 577         }
 578
 579         for (tag_directive = default_tag_directives;
 580                 tag_directive->handle; tag_directive ++) {
 581             if (!yaml_emitter_append_tag_directive(emitter, *tag_directive, 1))
 582                 return 0;
 583         }
 584
 585         implicit = event->data.document_start.implicit;
 586         if (!first || emitter->canonical) {
 587             implicit = 0;
 588         }
 589
 590         if ((event->data.document_start.version_directive ||
 591                     (event->data.document_start.tag_directives.start
 592                      != event->data.document_start.tag_directives.end)) &&
 593                 emitter->open_ended)
 594         {
 595             if (!yaml_emitter_write_indicator(emitter, "...", 1, 0, 0))
 596                 return 0;
 597             if (!yaml_emitter_write_indent(emitter))
 598                 return 0;
 599         }
 600
 601         if (event->data.document_start.version_directive) {
 602             implicit = 0;
 603             if (!yaml_emitter_write_indicator(emitter, "%YAML", 1, 0, 0))
 604                 return 0;
 605             if (!yaml_emitter_write_indicator(emitter, "1.1", 1, 0, 0))
 606                 return 0;
 607             if (!yaml_emitter_write_indent(emitter))
 608                 return 0;
 609         }
 610
 611         if (event->data.document_start.tag_directives.start
 612                 != event->data.document_start.tag_directives.end) {
 613             implicit = 0;
 614             for (tag_directive = event->data.document_start.tag_directives.start;
 615                     tag_directive != event->data.document_start.tag_directives.end;
 616                     tag_directive ++) {
 617                 if (!yaml_emitter_write_indicator(emitter, "%TAG", 1, 0, 0))
 618                     return 0;
 619                 if (!yaml_emitter_write_tag_handle(emitter, tag_directive->handle,
 620                             strlen((char *)tag_directive->handle)))
 621                     return 0;
 622                 if (!yaml_emitter_write_tag_content(emitter, tag_directive->prefix,
 623                             strlen((char *)tag_directive->prefix), 1))
 624                     return 0;
 625                 if (!yaml_emitter_write_indent(emitter))
 626                     return 0;
 627             }
 628         }
 629
 630         if (yaml_emitter_check_empty_document(emitter)) {
 631             implicit = 0;
 632         }
 633
 634         if (!implicit) {
 635             if (!yaml_emitter_write_indent(emitter))
 636                 return 0;
 637             if (!yaml_emitter_write_indicator(emitter, "---", 1, 0, 0))
 638                 return 0;
 639             if (emitter->canonical) {
 640                 if (!yaml_emitter_write_indent(emitter))
 641                     return 0;
 642             }
 643         }
 644
 645         emitter->state = YAML_EMIT_DOCUMENT_CONTENT_STATE;
 646
 647         return 1;
 648     }
 649
 650     else if (event->type == YAML_STREAM_END_EVENT)
 651     {
 652         if (emitter->open_ended)
 653         {
 654             if (!yaml_emitter_write_indicator(emitter, "...", 1, 0, 0))
 655                 return 0;
 656             if (!yaml_emitter_write_indent(emitter))
 657                 return 0;
 658         }
 659
 660         if (!yaml_emitter_flush(emitter))
 661             return 0;
 662
 663         emitter->state = YAML_EMIT_END_STATE;
 664
 665         return 1;
 666     }
 667
 668     return yaml_emitter_set_emitter_error(emitter,
 669             "expected DOCUMENT-START or STREAM-END");
 670 }
 671
 672 /*
 673  * Expect the root node.
 674  */
 675
 676 static int
 677 yaml_emitter_emit_document_content(yaml_emitter_t *emitter,
 678         yaml_event_t *event)
 679 {
 680     if (!PUSH(emitter, emitter->states, YAML_EMIT_DOCUMENT_END_STATE))
 681         return 0;
 682
 683     return yaml_emitter_emit_node(emitter, event, 1, 0, 0, 0);
 684 }
 685
 686 /*
 687  * Expect DOCUMENT-END.
 688  */
 689
 690 static int
 691 yaml_emitter_emit_document_end(yaml_emitter_t *emitter,
 692         yaml_event_t *event)
 693 {
 694     if (event->type == YAML_DOCUMENT_END_EVENT)
 695     {
 696         if (!yaml_emitter_write_indent(emitter))
 697             return 0;
 698         if (!event->data.document_end.implicit) {
 699             if (!yaml_emitter_write_indicator(emitter, "...", 1, 0, 0))
 700                 return 0;
 701             if (!yaml_emitter_write_indent(emitter))
 702                 return 0;
 703         }
 704         if (!yaml_emitter_flush(emitter))
 705             return 0;
 706
 707         emitter->state = YAML_EMIT_DOCUMENT_START_STATE;
 708
 709         while (!STACK_EMPTY(emitter, emitter->tag_directives)) {
 710             yaml_tag_directive_t tag_directive = POP(emitter,
 711                     emitter->tag_directives);
 712             yaml_free(tag_directive.handle);
 713             yaml_free(tag_directive.prefix);
 714         }
 715
 716         return 1;
 717     }
 718
 719     return yaml_emitter_set_emitter_error(emitter,
 720             "expected DOCUMENT-END");
 721 }
 722
 723 /*
 724  *
 725  * Expect a flow item node.
 726  */
 727
 728 static int
 729 yaml_emitter_emit_flow_sequence_item(yaml_emitter_t *emitter,
 730         yaml_event_t *event, int first)
 731 {
 732     if (first)
 733     {
 734         if (!yaml_emitter_write_indicator(emitter, "[", 1, 1, 0))
 735             return 0;
 736         if (!yaml_emitter_increase_indent(emitter, 1, 0))
 737             return 0;
 738         emitter->flow_level ++;
 739     }
 740
 741     if (event->type == YAML_SEQUENCE_END_EVENT)
 742     {
 743         emitter->flow_level --;
 744         emitter->indent = POP(emitter, emitter->indents);
 745         if (emitter->canonical && !first) {
 746             if (!yaml_emitter_write_indicator(emitter, ",", 0, 0, 0))
 747                 return 0;
 748             if (!yaml_emitter_write_indent(emitter))
 749                 return 0;
 750         }
 751         if (!yaml_emitter_write_indicator(emitter, "]", 0, 0, 0))
 752             return 0;
 753         emitter->state = POP(emitter, emitter->states);
 754
 755         return 1;
 756     }
 757
 758     if (!first) {
 759         if (!yaml_emitter_write_indicator(emitter, ",", 0, 0, 0))
 760             return 0;
 761     }
 762
 763     if (emitter->canonical || emitter->column > emitter->best_width) {
 764         if (!yaml_emitter_write_indent(emitter))
 765             return 0;
 766     }
 767     if (!PUSH(emitter, emitter->states, YAML_EMIT_FLOW_SEQUENCE_ITEM_STATE))
 768         return 0;
 769
 770     return yaml_emitter_emit_node(emitter, event, 0, 1, 0, 0);
 771 }
 772
 773 /*
 774  * Expect a flow key node.
 775  */
 776
 777 static int
 778 yaml_emitter_emit_flow_mapping_key(yaml_emitter_t *emitter,
 779         yaml_event_t *event, int first)
 780 {
 781     if (first)
 782     {
 783         if (!yaml_emitter_write_indicator(emitter, "{", 1, 1, 0))
 784             return 0;
 785         if (!yaml_emitter_increase_indent(emitter, 1, 0))
 786             return 0;
 787         emitter->flow_level ++;
 788     }
 789
 790     if (event->type == YAML_MAPPING_END_EVENT)
 791     {
 792         emitter->flow_level --;
 793         emitter->indent = POP(emitter, emitter->indents);
 794         if (emitter->canonical && !first) {
 795             if (!yaml_emitter_write_indicator(emitter, ",", 0, 0, 0))
 796                 return 0;
 797             if (!yaml_emitter_write_indent(emitter))
 798                 return 0;
 799         }
 800         if (!yaml_emitter_write_indicator(emitter, "}", 0, 0, 0))
 801             return 0;
 802         emitter->state = POP(emitter, emitter->states);
 803
 804         return 1;
 805     }
 806
 807     if (!first) {
 808         if (!yaml_emitter_write_indicator(emitter, ",", 0, 0, 0))
 809             return 0;
 810     }
 811     if (emitter->canonical || emitter->column > emitter->best_width) {
 812         if (!yaml_emitter_write_indent(emitter))
 813             return 0;
 814     }
 815
 816     if (!emitter->canonical && yaml_emitter_check_simple_key(emitter))
 817     {
 818         if (!PUSH(emitter, emitter->states,
 819                     YAML_EMIT_FLOW_MAPPING_SIMPLE_VALUE_STATE))
 820             return 0;
 821
 822         return yaml_emitter_emit_node(emitter, event, 0, 0, 1, 1);
 823     }
 824     else
 825     {
 826         if (!yaml_emitter_write_indicator(emitter, "?", 1, 0, 0))
 827             return 0;
 828         if (!PUSH(emitter, emitter->states,
 829                     YAML_EMIT_FLOW_MAPPING_VALUE_STATE))
 830             return 0;
 831
 832         return yaml_emitter_emit_node(emitter, event, 0, 0, 1, 0);
 833     }
 834 }
 835
 836 /*
 837  * Expect a flow value node.
 838  */
 839
 840 static int
 841 yaml_emitter_emit_flow_mapping_value(yaml_emitter_t *emitter,
 842         yaml_event_t *event, int simple)
 843 {
 844     if (simple) {
 845         if (!yaml_emitter_write_indicator(emitter, ":", 0, 0, 0))
 846             return 0;
 847     }
 848     else {
 849         if (emitter->canonical || emitter->column > emitter->best_width) {
 850             if (!yaml_emitter_write_indent(emitter))
 851                 return 0;
 852         }
 853         if (!yaml_emitter_write_indicator(emitter, ":", 1, 0, 0))
 854             return 0;
 855     }
 856     if (!PUSH(emitter, emitter->states, YAML_EMIT_FLOW_MAPPING_KEY_STATE))
 857         return 0;
 858     return yaml_emitter_emit_node(emitter, event, 0, 0, 1, 0);
 859 }
 860
 861 /*
 862  * Expect a block item node.
 863  */
 864
 865 static int
 866 yaml_emitter_emit_block_sequence_item(yaml_emitter_t *emitter,
 867         yaml_event_t *event, int first)
 868 {
 869     if (first)
 870     {
 871         if (!yaml_emitter_increase_indent(emitter, 0,
 872                     (emitter->mapping_context && !emitter->indention)))
 873             return 0;
 874     }
 875
 876     if (event->type == YAML_SEQUENCE_END_EVENT)
 877     {
 878         emitter->indent = POP(emitter, emitter->indents);
 879         emitter->state = POP(emitter, emitter->states);
 880
 881         return 1;
 882     }
 883
 884     if (!yaml_emitter_write_indent(emitter))
 885         return 0;
 886     if (!yaml_emitter_write_indicator(emitter, "-", 1, 0, 1))
 887         return 0;
 888     if (!PUSH(emitter, emitter->states,
 889                 YAML_EMIT_BLOCK_SEQUENCE_ITEM_STATE))
 890         return 0;
 891
 892     return yaml_emitter_emit_node(emitter, event, 0, 1, 0, 0);
 893 }
 894
 895 /*
 896  * Expect a block key node.
 897  */
 898
 899 static int
 900 yaml_emitter_emit_block_mapping_key(yaml_emitter_t *emitter,
 901         yaml_event_t *event, int first)
 902 {
 903     if (first)
 904     {
 905         if (!yaml_emitter_increase_indent(emitter, 0, 0))
 906             return 0;
 907     }
 908
 909     if (event->type == YAML_MAPPING_END_EVENT)
 910     {
 911         emitter->indent = POP(emitter, emitter->indents);
 912         emitter->state = POP(emitter, emitter->states);
 913
 914         return 1;
 915     }
 916
 917     if (!yaml_emitter_write_indent(emitter))
 918         return 0;
 919
 920     if (yaml_emitter_check_simple_key(emitter))
 921     {
 922         if (!PUSH(emitter, emitter->states,
 923                     YAML_EMIT_BLOCK_MAPPING_SIMPLE_VALUE_STATE))
 924             return 0;
 925
 926         return yaml_emitter_emit_node(emitter, event, 0, 0, 1, 1);
 927     }
 928     else
 929     {
 930         if (!yaml_emitter_write_indicator(emitter, "?", 1, 0, 1))
 931             return 0;
 932         if (!PUSH(emitter, emitter->states,
 933                     YAML_EMIT_BLOCK_MAPPING_VALUE_STATE))
 934             return 0;
 935
 936         return yaml_emitter_emit_node(emitter, event, 0, 0, 1, 0);
 937     }
 938 }
 939
 940 /*
 941  * Expect a block value node.
 942  */
 943
 944 static int
 945 yaml_emitter_emit_block_mapping_value(yaml_emitter_t *emitter,
 946         yaml_event_t *event, int simple)
 947 {
 948     if (simple) {
 949         if (!yaml_emitter_write_indicator(emitter, ":", 0, 0, 0))
 950             return 0;
 951     }
 952     else {
 953         if (!yaml_emitter_write_indent(emitter))
 954             return 0;
 955         if (!yaml_emitter_write_indicator(emitter, ":", 1, 0, 1))
 956             return 0;
 957     }
 958     if (!PUSH(emitter, emitter->states,
 959                 YAML_EMIT_BLOCK_MAPPING_KEY_STATE))
 960         return 0;
 961
 962     return yaml_emitter_emit_node(emitter, event, 0, 0, 1, 0);
 963 }
 964
 965 /*
 966  * Expect a node.
 967  */
 968
 969 static int
 970 yaml_emitter_emit_node(yaml_emitter_t *emitter, yaml_event_t *event,
 971         int root, int sequence, int mapping, int simple_key)
 972 {
 973     emitter->root_context = root;
 974     emitter->sequence_context = sequence;
 975     emitter->mapping_context = mapping;
 976     emitter->simple_key_context = simple_key;
 977
 978     switch (event->type)
 979     {
 980         case YAML_ALIAS_EVENT:
 981             return yaml_emitter_emit_alias(emitter, event);
 982
 983         case YAML_SCALAR_EVENT:
 984             return yaml_emitter_emit_scalar(emitter, event);
 985
 986         case YAML_SEQUENCE_START_EVENT:
 987             return yaml_emitter_emit_sequence_start(emitter, event);
 988
 989         case YAML_MAPPING_START_EVENT:
 990             return yaml_emitter_emit_mapping_start(emitter, event);
 991
 992         default:
 993             return yaml_emitter_set_emitter_error(emitter,
 994                     "expected SCALAR, SEQUENCE-START, MAPPING-START, or ALIAS");
 995     }
 996
 997     return 0;
 998 }
 999
1000 /*
1001  * Expect ALIAS.
1002  */
1003
1004 static int
1005 yaml_emitter_emit_alias(yaml_emitter_t *emitter, yaml_event_t *event)
1006 {
1007     if (!yaml_emitter_process_anchor(emitter))
1008         return 0;
1009     emitter->state = POP(emitter, emitter->states);
1010
1011     return 1;
1012 }
1013
1014 /*
1015  * Expect SCALAR.
1016  */
1017
1018 static int
1019 yaml_emitter_emit_scalar(yaml_emitter_t *emitter, yaml_event_t *event)
1020 {
1021     if (!yaml_emitter_select_scalar_style(emitter, event))
1022         return 0;
1023     if (!yaml_emitter_process_anchor(emitter))
1024         return 0;
1025     if (!yaml_emitter_process_tag(emitter))
1026         return 0;
1027     if (!yaml_emitter_increase_indent(emitter, 1, 0))
1028         return 0;
1029     if (!yaml_emitter_process_scalar(emitter))
1030         return 0;
1031     emitter->indent = POP(emitter, emitter->indents);
1032     emitter->state = POP(emitter, emitter->states);
1033
1034     return 1;
1035 }
1036
1037 /*
1038  * Expect SEQUENCE-START.
1039  */
1040
1041 static int
1042 yaml_emitter_emit_sequence_start(yaml_emitter_t *emitter, yaml_event_t *event)
1043 {
1044     if (!yaml_emitter_process_anchor(emitter))
1045         return 0;
1046     if (!yaml_emitter_process_tag(emitter))
1047         return 0;
1048
1049     if (emitter->flow_level || emitter->canonical
1050             || event->data.sequence_start.style == YAML_FLOW_SEQUENCE_STYLE
1051             || yaml_emitter_check_empty_sequence(emitter)) {
1052         emitter->state = YAML_EMIT_FLOW_SEQUENCE_FIRST_ITEM_STATE;
1053     }
1054     else {
1055         emitter->state = YAML_EMIT_BLOCK_SEQUENCE_FIRST_ITEM_STATE;
1056     }
1057
1058     return 1;
1059 }
1060
1061 /*
1062  * Expect MAPPING-START.
1063  */
1064
1065 static int
1066 yaml_emitter_emit_mapping_start(yaml_emitter_t *emitter, yaml_event_t *event)
1067 {
1068     if (!yaml_emitter_process_anchor(emitter))
1069         return 0;
1070     if (!yaml_emitter_process_tag(emitter))
1071         return 0;
1072
1073     if (emitter->flow_level || emitter->canonical
1074             || event->data.mapping_start.style == YAML_FLOW_MAPPING_STYLE
1075             || yaml_emitter_check_empty_mapping(emitter)) {
1076         emitter->state = YAML_EMIT_FLOW_MAPPING_FIRST_KEY_STATE;
1077     }
1078     else {
1079         emitter->state = YAML_EMIT_BLOCK_MAPPING_FIRST_KEY_STATE;
1080     }
1081
1082     return 1;
1083 }
1084
1085 /*
1086  * Check if the document content is an empty scalar.
1087  */
1088
1089 static int
1090 yaml_emitter_check_empty_document(yaml_emitter_t *emitter)
1091 {
1092     return 0;
1093 }
1094
1095 /*
1096  * Check if the next events represent an empty sequence.
1097  */
1098
1099 static int
1100 yaml_emitter_check_empty_sequence(yaml_emitter_t *emitter)
1101 {
1102     if (emitter->events.tail - emitter->events.head < 2)
1103         return 0;
1104
1105     return (emitter->events.head[0].type == YAML_SEQUENCE_START_EVENT
1106             && emitter->events.head[1].type == YAML_SEQUENCE_END_EVENT);
1107 }
1108
1109 /*
1110  * Check if the next events represent an empty mapping.
1111  */
1112
1113 static int
1114 yaml_emitter_check_empty_mapping(yaml_emitter_t *emitter)
1115 {
1116     if (emitter->events.tail - emitter->events.head < 2)
1117         return 0;
1118
1119     return (emitter->events.head[0].type == YAML_MAPPING_START_EVENT
1120             && emitter->events.head[1].type == YAML_MAPPING_END_EVENT);
1121 }
1122
1123 /*
1124  * Check if the next node can be expressed as a simple key.
1125  */
1126
1127 static int
1128 yaml_emitter_check_simple_key(yaml_emitter_t *emitter)
1129 {
1130     yaml_event_t *event = emitter->events.head;
1131     size_t length = 0;
1132
1133     switch (event->type)
1134     {
1135         case YAML_ALIAS_EVENT:
1136             length += emitter->anchor_data.anchor_length;
1137             break;
1138
1139         case YAML_SCALAR_EVENT:
1140             if (emitter->scalar_data.multiline)
1141                 return 0;
1142             length += emitter->anchor_data.anchor_length
1143                 + emitter->tag_data.handle_length
1144                 + emitter->tag_data.suffix_length
1145                 + emitter->scalar_data.length;
1146             break;
1147
1148         case YAML_SEQUENCE_START_EVENT:
1149             if (!yaml_emitter_check_empty_sequence(emitter))
1150                 return 0;
1151             length += emitter->anchor_data.anchor_length
1152                 + emitter->tag_data.handle_length
1153                 + emitter->tag_data.suffix_length;
1154             break;
1155
1156         case YAML_MAPPING_START_EVENT:
1157             if (!yaml_emitter_check_empty_sequence(emitter))
1158                 return 0;
1159             length += emitter->anchor_data.anchor_length
1160                 + emitter->tag_data.handle_length
1161                 + emitter->tag_data.suffix_length;
1162             break;
1163
1164         default:
1165             return 0;
1166     }
1167
1168     if (length > 128)
1169         return 0;
1170
1171     return 1;
1172 }
1173
1174 /*
1175  * Determine an acceptable scalar style.
1176  */
1177
1178 static int
1179 yaml_emitter_select_scalar_style(yaml_emitter_t *emitter, yaml_event_t *event)
1180 {
1181     yaml_scalar_style_t style = event->data.scalar.style;
1182     int no_tag = (!emitter->tag_data.handle && !emitter->tag_data.suffix);
1183
1184     if (no_tag && !event->data.scalar.plain_implicit
1185             && !event->data.scalar.quoted_implicit) {
1186         return yaml_emitter_set_emitter_error(emitter,
1187                 "neither tag nor implicit flags are specified");
1188     }
1189
1190     if (style == YAML_ANY_SCALAR_STYLE)
1191         style = YAML_PLAIN_SCALAR_STYLE;
1192
1193     if (emitter->canonical)
1194         style = YAML_DOUBLE_QUOTED_SCALAR_STYLE;
1195
1196     if (emitter->simple_key_context && emitter->scalar_data.multiline)
1197         style = YAML_DOUBLE_QUOTED_SCALAR_STYLE;
1198
1199     if (style == YAML_PLAIN_SCALAR_STYLE)
1200     {
1201         if ((emitter->flow_level && !emitter->scalar_data.flow_plain_allowed)
1202                 || (!emitter->flow_level && !emitter->scalar_data.block_plain_allowed))
1203             style = YAML_SINGLE_QUOTED_SCALAR_STYLE;
1204         if (!emitter->scalar_data.length
1205                 && (emitter->flow_level || emitter->simple_key_context))
1206             style = YAML_SINGLE_QUOTED_SCALAR_STYLE;
1207         if (no_tag && !event->data.scalar.plain_implicit)
1208             style = YAML_SINGLE_QUOTED_SCALAR_STYLE;
1209     }
1210
1211     if (style == YAML_SINGLE_QUOTED_SCALAR_STYLE)
1212     {
1213         if (!emitter->scalar_data.single_quoted_allowed)
1214             style = YAML_DOUBLE_QUOTED_SCALAR_STYLE;
1215     }
1216
1217     if (style == YAML_LITERAL_SCALAR_STYLE || style == YAML_FOLDED_SCALAR_STYLE)
1218     {
1219         if (!emitter->scalar_data.block_allowed
1220                 || emitter->flow_level || emitter->simple_key_context)
1221             style = YAML_DOUBLE_QUOTED_SCALAR_STYLE;
1222     }
1223
1224     if (no_tag && !event->data.scalar.quoted_implicit
1225             && style != YAML_PLAIN_SCALAR_STYLE)
1226     {
1227         emitter->tag_data.handle = (yaml_char_t *)"!";
1228         emitter->tag_data.handle_length = 1;
1229     }
1230
1231     emitter->scalar_data.style = style;
1232
1233     return 1;
1234 }
1235
1236 /*
1237  * Write an achor.
1238  */
1239
1240 static int
1241 yaml_emitter_process_anchor(yaml_emitter_t *emitter)
1242 {
1243     if (!emitter->anchor_data.anchor)
1244         return 1;
1245
1246     if (!yaml_emitter_write_indicator(emitter,
1247                 (emitter->anchor_data.alias ? "*" : "&"), 1, 0, 0))
1248         return 0;
1249
1250     return yaml_emitter_write_anchor(emitter,
1251             emitter->anchor_data.anchor, emitter->anchor_data.anchor_length);
1252 }
1253
1254 /*
1255  * Write a tag.
1256  */
1257
1258 static int
1259 yaml_emitter_process_tag(yaml_emitter_t *emitter)
1260 {
1261     if (!emitter->tag_data.handle && !emitter->tag_data.suffix)
1262         return 1;
1263
1264     if (emitter->tag_data.handle)
1265     {
1266         if (!yaml_emitter_write_tag_handle(emitter, emitter->tag_data.handle,
1267                     emitter->tag_data.handle_length))
1268             return 0;
1269         if (emitter->tag_data.suffix) {
1270             if (!yaml_emitter_write_tag_content(emitter, emitter->tag_data.suffix,
1271                         emitter->tag_data.suffix_length, 0))
1272                 return 0;
1273         }
1274     }
1275     else
1276     {
1277         if (!yaml_emitter_write_indicator(emitter, "!<", 1, 0, 0))
1278             return 0;
1279         if (!yaml_emitter_write_tag_content(emitter, emitter->tag_data.suffix,
1280                     emitter->tag_data.suffix_length, 0))
1281             return 0;
1282         if (!yaml_emitter_write_indicator(emitter, ">", 0, 0, 0))
1283             return 0;
1284     }
1285
1286     return 1;
1287 }
1288
1289 /*
1290  * Write a scalar.
1291  */
1292
1293 static int
1294 yaml_emitter_process_scalar(yaml_emitter_t *emitter)
1295 {
1296     switch (emitter->scalar_data.style)
1297     {
1298         case YAML_PLAIN_SCALAR_STYLE:
1299             return yaml_emitter_write_plain_scalar(emitter,
1300                     emitter->scalar_data.value, emitter->scalar_data.length,
1301                     !emitter->simple_key_context);
1302
1303         case YAML_SINGLE_QUOTED_SCALAR_STYLE:
1304             return yaml_emitter_write_single_quoted_scalar(emitter,
1305                     emitter->scalar_data.value, emitter->scalar_data.length,
1306                     !emitter->simple_key_context);
1307
1308         case YAML_DOUBLE_QUOTED_SCALAR_STYLE:
1309             return yaml_emitter_write_double_quoted_scalar(emitter,
1310                     emitter->scalar_data.value, emitter->scalar_data.length,
1311                     !emitter->simple_key_context);
1312
1313         case YAML_LITERAL_SCALAR_STYLE:
1314             return yaml_emitter_write_literal_scalar(emitter,
1315                     emitter->scalar_data.value, emitter->scalar_data.length);
1316
1317         case YAML_FOLDED_SCALAR_STYLE:
1318             return yaml_emitter_write_folded_scalar(emitter,
1319                     emitter->scalar_data.value, emitter->scalar_data.length);
1320
1321         default:
1322             assert(1);      /* Impossible. */
1323     }
1324
1325     return 0;
1326 }
1327
1328 /*
1329  * Check if a %YAML directive is valid.
1330  */
1331
1332 static int
1333 yaml_emitter_analyze_version_directive(yaml_emitter_t *emitter,
1334         yaml_version_directive_t version_directive)
1335 {
1336     if (version_directive.major != 1 || version_directive.minor != 1) {
1337         return yaml_emitter_set_emitter_error(emitter,
1338                 "incompatible %YAML directive");
1339     }
1340
1341     return 1;
1342 }
1343
1344 /*
1345  * Check if a %TAG directive is valid.
1346  */
1347
1348 static int
1349 yaml_emitter_analyze_tag_directive(yaml_emitter_t *emitter,
1350         yaml_tag_directive_t tag_directive)
1351 {
1352     yaml_string_t handle = STRING(tag_directive.handle,
1353             strlen((char *)tag_directive.handle));
1354     yaml_string_t prefix = STRING(tag_directive.prefix,
1355             strlen((char *)tag_directive.prefix));
1356
1357     if (handle.start == handle.end) {
1358         return yaml_emitter_set_emitter_error(emitter,
1359                 "tag handle must not be empty");
1360     }
1361
1362     if (handle.start[0] != '!') {
1363         return yaml_emitter_set_emitter_error(emitter,
1364                 "tag handle must start with '!'");
1365     }
1366
1367     if (handle.end[-1] != '!') {
1368         return yaml_emitter_set_emitter_error(emitter,
1369                 "tag handle must end with '!'");
1370     }
1371
1372     handle.pointer ++;
1373
1374     while (handle.pointer < handle.end-1) {
1375         if (!IS_ALPHA(handle)) {
1376             return yaml_emitter_set_emitter_error(emitter,
1377                     "tag handle must contain alphanumerical characters only");
1378         }
1379         MOVE(handle);
1380     }
1381
1382     if (prefix.start == prefix.end) {
1383         return yaml_emitter_set_emitter_error(emitter,
1384                 "tag prefix must not be empty");
1385     }
1386
1387     return 1;
1388 }
1389
1390 /*
1391  * Check if an anchor is valid.
1392  */
1393
1394 static int
1395 yaml_emitter_analyze_anchor(yaml_emitter_t *emitter,
1396         yaml_char_t *anchor, int alias)
1397 {
1398     yaml_string_t string = STRING(anchor, strlen((char *)anchor));
1399
1400     if (string.start == string.end) {
1401         return yaml_emitter_set_emitter_error(emitter, alias ?
1402                 "alias value must not be empty" :
1403                 "anchor value must not be empty");
1404     }
1405
1406     while (string.pointer != string.end) {
1407         if (!IS_ALPHA(string)) {
1408             return yaml_emitter_set_emitter_error(emitter, alias ?
1409                     "alias value must contain alphanumerical characters only" :
1410                     "anchor value must contain alphanumerical characters only");
1411         }
1412         MOVE(string);
1413     }
1414
1415     emitter->anchor_data.anchor = string.start;
1416     emitter->anchor_data.anchor_length = string.end - string.start;
1417     emitter->anchor_data.alias = alias;
1418
1419     return 1;
1420 }
1421
1422 /*
1423  * Check if a tag is valid.
1424  */
1425
1426 static int
1427 yaml_emitter_analyze_tag(yaml_emitter_t *emitter,
1428         yaml_char_t *tag)
1429 {
1430     yaml_string_t string = STRING(tag, strlen((char *)tag));
1431     yaml_tag_directive_t *tag_directive;
1432
1433     if (string.start == string.end) {
1434         return yaml_emitter_set_emitter_error(emitter,
1435                 "tag value must not be empty");
1436     }
1437
1438     for (tag_directive = emitter->tag_directives.start;
1439             tag_directive != emitter->tag_directives.top; tag_directive ++) {
1440         size_t prefix_length = strlen((char *)tag_directive->prefix);
1441         if (prefix_length < (size_t)(string.end - string.start)
1442                 && strncmp((char *)tag_directive->prefix, (char *)string.start,
1443                     prefix_length) == 0)
1444         {
1445             emitter->tag_data.handle = tag_directive->handle;
1446             emitter->tag_data.handle_length =
1447                 strlen((char *)tag_directive->handle);
1448             emitter->tag_data.suffix = string.start + prefix_length;
1449             emitter->tag_data.suffix_length =
1450                 (string.end - string.start) - prefix_length;
1451             return 1;
1452         }
1453     }
1454
1455     emitter->tag_data.suffix = string.start;
1456     emitter->tag_data.suffix_length = string.end - string.start;
1457
1458     return 1;
1459 }
1460
1461 /*
1462  * Check if a scalar is valid.
1463  */
1464
1465 static int
1466 yaml_emitter_analyze_scalar(yaml_emitter_t *emitter,
1467         yaml_char_t *value, size_t length)
1468 {
1469     yaml_string_t string = STRING(value, length);
1470
1471     int block_indicators = 0;
1472     int flow_indicators = 0;
1473     int line_breaks = 0;
1474     int special_characters = 0;
1475
1476     int leading_space = 0;
1477     int leading_break = 0;
1478     int trailing_space = 0;
1479     int trailing_break = 0;
1480     int break_space = 0;
1481     int space_break = 0;
1482
1483     int preceeded_by_whitespace = 0;
1484     int followed_by_whitespace = 0;
1485     int previous_space = 0;
1486     int previous_break = 0;
1487
1488     emitter->scalar_data.value = value;
1489     emitter->scalar_data.length = length;
1490
1491     if (string.start == string.end)
1492     {
1493         emitter->scalar_data.multiline = 0;
1494         emitter->scalar_data.flow_plain_allowed = 0;
1495         emitter->scalar_data.block_plain_allowed = 1;
1496         emitter->scalar_data.single_quoted_allowed = 1;
1497         emitter->scalar_data.block_allowed = 0;
1498
1499         return 1;
1500     }
1501
1502     if ((CHECK_AT(string, '-', 0)
1503                 && CHECK_AT(string, '-', 1)
1504                 && CHECK_AT(string, '-', 2))
1505             || (CHECK_AT(string, '.', 0)
1506                 && CHECK_AT(string, '.', 1)
1507                 && CHECK_AT(string, '.', 2))) {
1508         block_indicators = 1;
1509         flow_indicators = 1;
1510     }
1511
1512     preceeded_by_whitespace = 1;
1513     followed_by_whitespace = IS_BLANKZ_AT(string, WIDTH(string));
1514
1515     while (string.pointer != string.end)
1516     {
1517         if (string.start == string.pointer)
1518         {
1519             if (CHECK(string, '#') || CHECK(string, ',')
1520                     || CHECK(string, '[') || CHECK(string, ']')
1521                     || CHECK(string, '{') || CHECK(string, '}')
1522                     || CHECK(string, '&') || CHECK(string, '*')
1523                     || CHECK(string, '!') || CHECK(string, '|')
1524                     || CHECK(string, '>') || CHECK(string, '\'')
1525                     || CHECK(string, '"') || CHECK(string, '%')
1526                     || CHECK(string, '@') || CHECK(string, '`')) {
1527                 flow_indicators = 1;
1528                 block_indicators = 1;
1529             }
1530
1531             if (CHECK(string, '?') || CHECK(string, ':')) {
1532                 flow_indicators = 1;
1533                 if (followed_by_whitespace) {
1534                     block_indicators = 1;
1535                 }
1536             }
1537
1538             if (CHECK(string, '-') && followed_by_whitespace) {
1539                 flow_indicators = 1;
1540                 block_indicators = 1;
1541             }
1542         }
1543         else
1544         {
1545             if (CHECK(string, ',') || CHECK(string, '?')
1546                     || CHECK(string, '[') || CHECK(string, ']')
1547                     || CHECK(string, '{') || CHECK(string, '}')) {
1548                 flow_indicators = 1;
1549             }
1550
1551             if (CHECK(string, ':')) {
1552                 flow_indicators = 1;
1553                 if (followed_by_whitespace) {
1554                     block_indicators = 1;
1555                 }
1556             }
1557
1558             if (CHECK(string, '#') && preceeded_by_whitespace) {
1559                 flow_indicators = 1;
1560                 block_indicators = 1;
1561             }
1562         }
1563
1564         if (!IS_PRINTABLE(string)
1565                 || (!IS_ASCII(string) && !emitter->unicode)) {
1566             special_characters = 1;
1567         }
1568
1569         if (IS_BREAK(string)) {
1570             line_breaks = 1;
1571         }
1572
1573         if (IS_SPACE(string))
1574         {
1575             if (string.start == string.pointer) {
1576                 leading_space = 1;
1577             }
1578             if (string.pointer+WIDTH(string) == string.end) {
1579                 trailing_space = 1;
1580             }
1581             if (previous_break) {
1582                 break_space = 1;
1583             }
1584             previous_space = 1;
1585             previous_break = 0;
1586         }
1587         else if (IS_BREAK(string))
1588         {
1589             if (string.start == string.pointer) {
1590                 leading_break = 1;
1591             }
1592             if (string.pointer+WIDTH(string) == string.end) {
1593                 trailing_break = 1;
1594             }
1595             if (previous_space) {
1596                 space_break = 1;
1597             }
1598             previous_space = 0;
1599             previous_break = 1;
1600         }
1601         else
1602         {
1603             previous_space = 0;
1604             previous_break = 0;
1605         }
1606
1607         preceeded_by_whitespace = IS_BLANKZ(string);
1608         MOVE(string);
1609         if (string.pointer != string.end) {
1610             followed_by_whitespace = IS_BLANKZ_AT(string, WIDTH(string));
1611         }
1612     }
1613
1614     emitter->scalar_data.multiline = line_breaks;
1615
1616     emitter->scalar_data.flow_plain_allowed = 1;
1617     emitter->scalar_data.block_plain_allowed = 1;
1618     emitter->scalar_data.single_quoted_allowed = 1;
1619     emitter->scalar_data.block_allowed = 1;
1620
1621     if (leading_space || leading_break || trailing_space || trailing_break) {
1622         emitter->scalar_data.flow_plain_allowed = 0;
1623         emitter->scalar_data.block_plain_allowed = 0;
1624     }
1625
1626     if (trailing_space) {
1627         emitter->scalar_data.block_allowed = 0;
1628     }
1629
1630     if (break_space) {
1631         emitter->scalar_data.flow_plain_allowed = 0;
1632         emitter->scalar_data.block_plain_allowed = 0;
1633         emitter->scalar_data.single_quoted_allowed = 0;
1634     }
1635
1636     if (space_break || special_characters) {
1637         emitter->scalar_data.flow_plain_allowed = 0;
1638         emitter->scalar_data.block_plain_allowed = 0;
1639         emitter->scalar_data.single_quoted_allowed = 0;
1640         emitter->scalar_data.block_allowed = 0;
1641     }
1642
1643     if (line_breaks) {
1644         emitter->scalar_data.flow_plain_allowed = 0;
1645         emitter->scalar_data.block_plain_allowed = 0;
1646     }
1647
1648     if (flow_indicators) {
1649         emitter->scalar_data.flow_plain_allowed = 0;
1650     }
1651
1652     if (block_indicators) {
1653         emitter->scalar_data.block_plain_allowed = 0;
1654     }
1655
1656     return 1;
1657 }
1658
1659 /*
1660  * Check if the event data is valid.
1661  */
1662
1663 static int
1664 yaml_emitter_analyze_event(yaml_emitter_t *emitter,
1665         yaml_event_t *event)
1666 {
1667     emitter->anchor_data.anchor = NULL;
1668     emitter->anchor_data.anchor_length = 0;
1669     emitter->tag_data.handle = NULL;
1670     emitter->tag_data.handle_length = 0;
1671     emitter->tag_data.suffix = NULL;
1672     emitter->tag_data.suffix_length = 0;
1673     emitter->scalar_data.value = NULL;
1674     emitter->scalar_data.length = 0;
1675
1676     switch (event->type)
1677     {
1678         case YAML_ALIAS_EVENT:
1679             if (!yaml_emitter_analyze_anchor(emitter,
1680                         event->data.alias.anchor, 1))
1681                 return 0;
1682             return 1;
1683
1684         case YAML_SCALAR_EVENT:
1685             if (event->data.scalar.anchor) {
1686                 if (!yaml_emitter_analyze_anchor(emitter,
1687                             event->data.scalar.anchor, 0))
1688                     return 0;
1689             }
1690             if (event->data.scalar.tag && (emitter->canonical ||
1691                         (!event->data.scalar.plain_implicit
1692                          && !event->data.scalar.quoted_implicit))) {
1693                 if (!yaml_emitter_analyze_tag(emitter, event->data.scalar.tag))
1694                     return 0;
1695             }
1696             if (!yaml_emitter_analyze_scalar(emitter,
1697                         event->data.scalar.value, event->data.scalar.length))
1698                 return 0;
1699             return 1;
1700
1701         case YAML_SEQUENCE_START_EVENT:
1702             if (event->data.sequence_start.anchor) {
1703                 if (!yaml_emitter_analyze_anchor(emitter,
1704                             event->data.sequence_start.anchor, 0))
1705                     return 0;
1706             }
1707             if (event->data.sequence_start.tag && (emitter->canonical ||
1708                         !event->data.sequence_start.implicit)) {
1709                 if (!yaml_emitter_analyze_tag(emitter,
1710                             event->data.sequence_start.tag))
1711                     return 0;
1712             }
1713             return 1;
1714
1715         case YAML_MAPPING_START_EVENT:
1716             if (event->data.mapping_start.anchor) {
1717                 if (!yaml_emitter_analyze_anchor(emitter,
1718                             event->data.mapping_start.anchor, 0))
1719                     return 0;
1720             }
1721             if (event->data.mapping_start.tag && (emitter->canonical ||
1722                         !event->data.mapping_start.implicit)) {
1723                 if (!yaml_emitter_analyze_tag(emitter,
1724                             event->data.mapping_start.tag))
1725                     return 0;
1726             }
1727             return 1;
1728
1729         default:
1730             return 1;
1731     }
1732 }
1733
1734 /*
1735  * Write the BOM character.
1736  */
1737
1738 static int
1739 yaml_emitter_write_bom(yaml_emitter_t *emitter)
1740 {
1741     if (!FLUSH(emitter)) return 0;
1742
1743     *(emitter->buffer.pointer++) = (yaml_char_t) '\xEF';
1744     *(emitter->buffer.pointer++) = (yaml_char_t) '\xBB';
1745     *(emitter->buffer.pointer++) = (yaml_char_t) '\xBF';
1746
1747     return 1;
1748 }
1749
1750 static int
1751 yaml_emitter_write_indent(yaml_emitter_t *emitter)
1752 {
1753     int indent = (emitter->indent >= 0) ? emitter->indent : 0;
1754
1755     if (!emitter->indention || emitter->column > indent
1756             || (emitter->column == indent && !emitter->whitespace)) {
1757         if (!PUT_BREAK(emitter)) return 0;
1758     }
1759
1760     while (emitter->column < indent) {
1761         if (!PUT(emitter, ' ')) return 0;
1762     }
1763
1764     emitter->whitespace = 1;
1765     emitter->indention = 1;
1766
1767     return 1;
1768 }
1769
1770 static int
1771 yaml_emitter_write_indicator(yaml_emitter_t *emitter,
1772         char *indicator, int need_whitespace,
1773         int is_whitespace, int is_indention)
1774 {
1775     yaml_string_t string = STRING((yaml_char_t *)indicator, strlen(indicator));
1776
1777     if (need_whitespace && !emitter->whitespace) {
1778         if (!PUT(emitter, ' ')) return 0;
1779     }
1780
1781     while (string.pointer != string.end) {
1782         if (!WRITE(emitter, string)) return 0;
1783     }
1784
1785     emitter->whitespace = is_whitespace;
1786     emitter->indention = (emitter->indention && is_indention);
1787     emitter->open_ended = 0;
1788
1789     return 1;
1790 }
1791
1792 static int
1793 yaml_emitter_write_anchor(yaml_emitter_t *emitter,
1794         yaml_char_t *value, size_t length)
1795 {
1796     yaml_string_t string = STRING(value, length);
1797
1798     while (string.pointer != string.end) {
1799         if (!WRITE(emitter, string)) return 0;
1800     }
1801
1802     emitter->whitespace = 0;
1803     emitter->indention = 0;
1804
1805     return 1;
1806 }
1807
1808 static int
1809 yaml_emitter_write_tag_handle(yaml_emitter_t *emitter,
1810         yaml_char_t *value, size_t length)
1811 {
1812     yaml_string_t string = STRING(value, length);
1813
1814     if (!emitter->whitespace) {
1815         if (!PUT(emitter, ' ')) return 0;
1816     }
1817
1818     while (string.pointer != string.end) {
1819         if (!WRITE(emitter, string)) return 0;
1820     }
1821
1822     emitter->whitespace = 0;
1823     emitter->indention = 0;
1824
1825     return 1;
1826 }
1827
1828 static int
1829 yaml_emitter_write_tag_content(yaml_emitter_t *emitter,
1830         yaml_char_t *value, size_t length,
1831         int need_whitespace)
1832 {
1833     yaml_string_t string = STRING(value, length);
1834
1835     if (need_whitespace && !emitter->whitespace) {
1836         if (!PUT(emitter, ' ')) return 0;
1837     }
1838
1839     while (string.pointer != string.end) {
1840         if (IS_ALPHA(string)
1841                 || CHECK(string, ';') || CHECK(string, '/')
1842                 || CHECK(string, '?') || CHECK(string, ':')
1843                 || CHECK(string, '@') || CHECK(string, '&')
1844                 || CHECK(string, '=') || CHECK(string, '+')
1845                 || CHECK(string, '$') || CHECK(string, ',')
1846                 || CHECK(string, '_') || CHECK(string, '.')
1847                 || CHECK(string, '~') || CHECK(string, '*')
1848                 || CHECK(string, '\'') || CHECK(string, '(')
1849                 || CHECK(string, ')') || CHECK(string, '[')
1850                 || CHECK(string, ']')) {
1851             if (!WRITE(emitter, string)) return 0;
1852         }
1853         else {
1854             int width = WIDTH(string);
1855             unsigned int value;
1856             while (width --) {
1857                 value = *(string.pointer++);
1858                 if (!PUT(emitter, '%')) return 0;
1859                 if (!PUT(emitter, (value >> 4)
1860                             + ((value >> 4) < 10 ? '0' : 'A' - 10)))
1861                     return 0;
1862                 if (!PUT(emitter, (value & 0x0F)
1863                             + ((value & 0x0F) < 10 ? '0' : 'A' - 10)))
1864                     return 0;
1865             }
1866         }
1867     }
1868
1869     emitter->whitespace = 0;
1870     emitter->indention = 0;
1871
1872     return 1;
1873 }
1874
1875 static int
1876 yaml_emitter_write_plain_scalar(yaml_emitter_t *emitter,
1877         yaml_char_t *value, size_t length, int allow_breaks)
1878 {
1879     yaml_string_t string = STRING(value, length);
1880     int spaces = 0;
1881     int breaks = 0;
1882
1883     if (!emitter->whitespace) {
1884         if (!PUT(emitter, ' ')) return 0;
1885     }
1886
1887     while (string.pointer != string.end)
1888     {
1889         if (IS_SPACE(string))
1890         {
1891             if (allow_breaks && !spaces
1892                     && emitter->column > emitter->best_width
1893                     && !IS_SPACE_AT(string, 1)) {
1894                 if (!yaml_emitter_write_indent(emitter)) return 0;
1895                 MOVE(string);
1896             }
1897             else {
1898                 if (!WRITE(emitter, string)) return 0;
1899             }
1900             spaces = 1;
1901         }
1902         else if (IS_BREAK(string))
1903         {
1904             if (!breaks && CHECK(string, '\n')) {
1905                 if (!PUT_BREAK(emitter)) return 0;
1906             }
1907             if (!WRITE_BREAK(emitter, string)) return 0;
1908             emitter->indention = 1;
1909             breaks = 1;
1910         }
1911         else
1912         {
1913             if (breaks) {
1914                 if (!yaml_emitter_write_indent(emitter)) return 0;
1915             }
1916             if (!WRITE(emitter, string)) return 0;
1917             emitter->indention = 0;
1918             spaces = 0;
1919             breaks = 0;
1920         }
1921     }
1922
1923     emitter->whitespace = 0;
1924     emitter->indention = 0;
1925     if (emitter->root_context)
1926     {
1927         emitter->open_ended = 1;
1928     }
1929
1930     return 1;
1931 }
1932
1933 static int
1934 yaml_emitter_write_single_quoted_scalar(yaml_emitter_t *emitter,
1935         yaml_char_t *value, size_t length, int allow_breaks)
1936 {
1937     yaml_string_t string = STRING(value, length);
1938     int spaces = 0;
1939     int breaks = 0;
1940
1941     if (!yaml_emitter_write_indicator(emitter, "'", 1, 0, 0))
1942         return 0;
1943
1944     while (string.pointer != string.end)
1945     {
1946         if (IS_SPACE(string))
1947         {
1948             if (allow_breaks && !spaces
1949                     && emitter->column > emitter->best_width
1950                     && string.pointer != string.start
1951                     && string.pointer != string.end - 1
1952                     && !IS_SPACE_AT(string, 1)) {
1953                 if (!yaml_emitter_write_indent(emitter)) return 0;
1954                 MOVE(string);
1955             }
1956             else {
1957                 if (!WRITE(emitter, string)) return 0;
1958             }
1959             spaces = 1;
1960         }
1961         else if (IS_BREAK(string))
1962         {
1963             if (!breaks && CHECK(string, '\n')) {
1964                 if (!PUT_BREAK(emitter)) return 0;
1965             }
1966             if (!WRITE_BREAK(emitter, string)) return 0;
1967             emitter->indention = 1;
1968             breaks = 1;
1969         }
1970         else
1971         {
1972             if (breaks) {
1973                 if (!yaml_emitter_write_indent(emitter)) return 0;
1974             }
1975             if (CHECK(string, '\'')) {
1976                 if (!PUT(emitter, '\'')) return 0;
1977             }
1978             if (!WRITE(emitter, string)) return 0;
1979             emitter->indention = 0;
1980             spaces = 0;
1981             breaks = 0;
1982         }
1983     }
1984
1985     if (!yaml_emitter_write_indicator(emitter, "'", 0, 0, 0))
1986         return 0;
1987
1988     emitter->whitespace = 0;
1989     emitter->indention = 0;
1990
1991     return 1;
1992 }
1993
1994 static int
1995 yaml_emitter_write_double_quoted_scalar(yaml_emitter_t *emitter,
1996         yaml_char_t *value, size_t length, int allow_breaks)
1997 {
1998     yaml_string_t string = STRING(value, length);
1999     int spaces = 0;
2000
2001     if (!yaml_emitter_write_indicator(emitter, "\"", 1, 0, 0))
2002         return 0;
2003
2004     while (string.pointer != string.end)
2005     {
2006         if (!IS_PRINTABLE(string) || (!emitter->unicode && !IS_ASCII(string))
2007                 || IS_BOM(string) || IS_BREAK(string)
2008                 || CHECK(string, '"') || CHECK(string, '\\'))
2009         {
2010             unsigned char octet;
2011             unsigned int width;
2012             unsigned int value;
2013             int k;
2014
2015             octet = string.pointer[0];
2016             width = (octet & 0x80) == 0x00 ? 1 :
2017                     (octet & 0xE0) == 0xC0 ? 2 :
2018                     (octet & 0xF0) == 0xE0 ? 3 :
2019                     (octet & 0xF8) == 0xF0 ? 4 : 0;
2020             value = (octet & 0x80) == 0x00 ? octet & 0x7F :
2021                     (octet & 0xE0) == 0xC0 ? octet & 0x1F :
2022                     (octet & 0xF0) == 0xE0 ? octet & 0x0F :
2023                     (octet & 0xF8) == 0xF0 ? octet & 0x07 : 0;
2024             for (k = 1; k < (int)width; k ++) {
2025                 octet = string.pointer[k];
2026                 value = (value << 6) + (octet & 0x3F);
2027             }
2028             string.pointer += width;
2029
2030             if (!PUT(emitter, '\\')) return 0;
2031
2032             switch (value)
2033             {
2034                 case 0x00:
2035                     if (!PUT(emitter, '0')) return 0;
2036                     break;
2037
2038                 case 0x07:
2039                     if (!PUT(emitter, 'a')) return 0;
2040                     break;
2041
2042                 case 0x08:
2043                     if (!PUT(emitter, 'b')) return 0;
2044                     break;
2045
2046                 case 0x09:
2047                     if (!PUT(emitter, 't')) return 0;
2048                     break;
2049
2050                 case 0x0A:
2051                     if (!PUT(emitter, 'n')) return 0;
2052                     break;
2053
2054                 case 0x0B:
2055                     if (!PUT(emitter, 'v')) return 0;
2056                     break;
2057
2058                 case 0x0C:
2059                     if (!PUT(emitter, 'f')) return 0;
2060                     break;
2061
2062                 case 0x0D:
2063                     if (!PUT(emitter, 'r')) return 0;
2064                     break;
2065
2066                 case 0x1B:
2067                     if (!PUT(emitter, 'e')) return 0;
2068                     break;
2069
2070                 case 0x22:
2071                     if (!PUT(emitter, '\"')) return 0;
2072                     break;
2073
2074                 case 0x5C:
2075                     if (!PUT(emitter, '\\')) return 0;
2076                     break;
2077
2078                 case 0x85:
2079                     if (!PUT(emitter, 'N')) return 0;
2080                     break;
2081
2082                 case 0xA0:
2083                     if (!PUT(emitter, '_')) return 0;
2084                     break;
2085
2086                 case 0x2028:
2087                     if (!PUT(emitter, 'L')) return 0;
2088                     break;
2089
2090                 case 0x2029:
2091                     if (!PUT(emitter, 'P')) return 0;
2092                     break;
2093
2094                 default:
2095                     if (value <= 0xFF) {
2096                         if (!PUT(emitter, 'x')) return 0;
2097                         width = 2;
2098                     }
2099                     else if (value <= 0xFFFF) {
2100                         if (!PUT(emitter, 'u')) return 0;
2101                         width = 4;
2102                     }
2103                     else {
2104                         if (!PUT(emitter, 'U')) return 0;
2105                         width = 8;
2106                     }
2107                     for (k = (width-1)*4; k >= 0; k -= 4) {
2108                         int digit = (value >> k) & 0x0F;
2109                         if (!PUT(emitter, digit + (digit < 10 ? '0' : 'A'-10)))
2110                             return 0;
2111                     }
2112             }
2113             spaces = 0;
2114         }
2115         else if (IS_SPACE(string))
2116         {
2117             if (allow_breaks && !spaces
2118                     && emitter->column > emitter->best_width
2119                     && string.pointer != string.start
2120                     && string.pointer != string.end - 1) {
2121                 if (!yaml_emitter_write_indent(emitter)) return 0;
2122                 if (IS_SPACE_AT(string, 1)) {
2123                     if (!PUT(emitter, '\\')) return 0;
2124                 }
2125                 MOVE(string);
2126             }
2127             else {
2128                 if (!WRITE(emitter, string)) return 0;
2129             }
2130             spaces = 1;
2131         }
2132         else
2133         {
2134             if (!WRITE(emitter, string)) return 0;
2135             spaces = 0;
2136         }
2137     }
2138
2139     if (!yaml_emitter_write_indicator(emitter, "\"", 0, 0, 0))
2140         return 0;
2141
2142     emitter->whitespace = 0;
2143     emitter->indention = 0;
2144
2145     return 1;
2146 }
2147
2148 static int
2149 yaml_emitter_write_block_scalar_hints(yaml_emitter_t *emitter,
2150         yaml_string_t string)
2151 {
2152     char indent_hint[2];
2153     char *chomp_hint = NULL;
2154
2155     if (IS_SPACE(string) || IS_BREAK(string))
2156     {
2157         indent_hint[0] = '0' + (char)emitter->best_indent;
2158         indent_hint[1] = '\0';
2159         if (!yaml_emitter_write_indicator(emitter, indent_hint, 0, 0, 0))
2160             return 0;
2161     }
2162
2163     emitter->open_ended = 0;
2164
2165     string.pointer = string.end;
2166     if (string.start == string.pointer)
2167     {
2168         chomp_hint = "-";
2169     }
2170     else
2171     {
2172         do {
2173             string.pointer --;
2174         } while ((*string.pointer & 0xC0) == 0x80);
2175         if (!IS_BREAK(string))
2176         {
2177             chomp_hint = "-";
2178         }
2179         else if (string.start == string.pointer)
2180         {
2181             chomp_hint = "+";
2182             emitter->open_ended = 1;
2183         }
2184         else
2185         {
2186             do {
2187                 string.pointer --;
2188             } while ((*string.pointer & 0xC0) == 0x80);
2189             if (IS_BREAK(string))
2190             {
2191                 chomp_hint = "+";
2192                 emitter->open_ended = 1;
2193             }
2194         }
2195     }
2196
2197     if (chomp_hint)
2198     {
2199         if (!yaml_emitter_write_indicator(emitter, chomp_hint, 0, 0, 0))
2200             return 0;
2201     }
2202
2203     return 1;
2204 }
2205
2206 static int
2207 yaml_emitter_write_literal_scalar(yaml_emitter_t *emitter,
2208         yaml_char_t *value, size_t length)
2209 {
2210     yaml_string_t string = STRING(value, length);
2211     int breaks = 1;
2212
2213     if (!yaml_emitter_write_indicator(emitter, "|", 1, 0, 0))
2214         return 0;
2215     if (!yaml_emitter_write_block_scalar_hints(emitter, string))
2216         return 0;
2217     if (!PUT_BREAK(emitter)) return 0;
2218     emitter->indention = 1;
2219     emitter->whitespace = 1;
2220
2221     while (string.pointer != string.end)
2222     {
2223         if (IS_BREAK(string))
2224         {
2225             if (!WRITE_BREAK(emitter, string)) return 0;
2226             emitter->indention = 1;
2227             breaks = 1;
2228         }
2229         else
2230         {
2231             if (breaks) {
2232                 if (!yaml_emitter_write_indent(emitter)) return 0;
2233             }
2234             if (!WRITE(emitter, string)) return 0;
2235             emitter->indention = 0;
2236             breaks = 0;
2237         }
2238     }
2239
2240     return 1;
2241 }
2242
2243 static int
2244 yaml_emitter_write_folded_scalar(yaml_emitter_t *emitter,
2245         yaml_char_t *value, size_t length)
2246 {
2247     yaml_string_t string = STRING(value, length);
2248     int breaks = 1;
2249     int leading_spaces = 1;
2250
2251     if (!yaml_emitter_write_indicator(emitter, ">", 1, 0, 0))
2252         return 0;
2253     if (!yaml_emitter_write_block_scalar_hints(emitter, string))
2254         return 0;
2255     if (!PUT_BREAK(emitter)) return 0;
2256     emitter->indention = 1;
2257     emitter->whitespace = 1;
2258
2259     while (string.pointer != string.end)
2260     {
2261         if (IS_BREAK(string))
2262         {
2263             if (!breaks && !leading_spaces && CHECK(string, '\n')) {
2264                 int k = 0;
2265                 while (IS_BREAK_AT(string, k)) {
2266                     k += WIDTH_AT(string, k);
2267                 }
2268                 if (!IS_BLANKZ_AT(string, k)) {
2269                     if (!PUT_BREAK(emitter)) return 0;
2270                 }
2271             }
2272             if (!WRITE_BREAK(emitter, string)) return 0;
2273             emitter->indention = 1;
2274             breaks = 1;
2275         }
2276         else
2277         {
2278             if (breaks) {
2279                 if (!yaml_emitter_write_indent(emitter)) return 0;
2280                 leading_spaces = IS_BLANK(string);
2281             }
2282             if (!breaks && IS_SPACE(string) && !IS_SPACE_AT(string, 1)
2283                     && emitter->column > emitter->best_width) {
2284                 if (!yaml_emitter_write_indent(emitter)) return 0;
2285                 MOVE(string);
2286             }
2287             else {
2288                 if (!WRITE(emitter, string)) return 0;
2289             }
2290             emitter->indention = 0;
2291             breaks = 0;
2292         }
2293     }
2294
2295     return 1;
2296 }
2297