utils/themeeditor/skin_parser.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2010 Robert Bieber
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <ctype.h>
  26
  27 #include "skin_parser.h"
  28 #include "skin_debug.h"
  29 #include "tag_table.h"
  30 #include "symbols.h"
  31 #include "skin_scan.h"
  32
  33 /* Declaration of parse tree buffer */
  34 char skin_parse_tree[SKIN_MAX_MEMORY];
  35 int skin_current_block = 0;
  36
  37 /* Global variables for the parser */
  38 int skin_line = 0;
  39
  40 /* Auxiliary parsing functions (not visible at global scope) */
  41 struct skin_element* skin_parse_viewport(char** document);
  42 struct skin_element* skin_parse_line(char** document);
  43 struct skin_element* skin_parse_line_optional(char** document, int conditional);
  44 struct skin_element* skin_parse_sublines(char** document);
  45 struct skin_element* skin_parse_sublines_optional(char** document,
  46                                                   int conditional);
  47
  48 int skin_parse_tag(struct skin_element* element, char** document);
  49 int skin_parse_text(struct skin_element* element, char** document,
  50                     int conditional);
  51 int skin_parse_conditional(struct skin_element* element, char** document);
  52 int skin_parse_comment(struct skin_element* element, char** document);
  53 struct skin_element* skin_parse_code_as_arg(char** document);
  54
  55 struct skin_element* skin_parse(const char* document)
  56 {
  57
  58     struct skin_element* root = NULL;
  59     struct skin_element* last = NULL;
  60
  61     struct skin_element** to_write = 0;
  62
  63     char* cursor = (char*)document; /*Keeps track of location in the document*/
  64
  65     skin_line = 1;
  66
  67     while(*cursor != '\0')
  68     {
  69
  70         if(!root)
  71             to_write = &root;
  72         else
  73             to_write = &(last->next);
  74
  75
  76         *to_write = skin_parse_viewport(&cursor);
  77         last = *to_write;
  78         if(!last)
  79             return NULL;
  80
  81         /* Making sure last is at the end */
  82         while(last->next)
  83             last = last->next;
  84
  85     }
  86
  87     return root;
  88
  89 }
  90
  91 struct skin_element* skin_parse_viewport(char** document)
  92 {
  93
  94     struct skin_element* root = NULL;
  95     struct skin_element* last = NULL;
  96     struct skin_element* retval = NULL;
  97
  98     retval = skin_alloc_element();
  99     retval->type = VIEWPORT;
 100     retval->children_count = 1;
 101     retval->line = skin_line;
 102
 103     struct skin_element** to_write = 0;
 104
 105     char* cursor = *document; /* Keeps track of location in the document */
 106     char* bookmark; /* Used when we need to look ahead */
 107
 108     int sublines = 0; /* Flag for parsing sublines */
 109
 110     /* Parsing out the viewport tag if there is one */
 111     if(check_viewport(cursor))
 112     {
 113         retval->children_count = 2;
 114         retval->children = skin_alloc_children(2);
 115         retval->children[0] = skin_alloc_element();
 116         skin_parse_tag(retval->children[0], &cursor);
 117         if(*cursor == '\n')
 118         {
 119             cursor++;
 120             skin_line++;
 121         }
 122     }
 123     else
 124     {
 125         retval->children_count = 1;
 126         retval->children = skin_alloc_children(1);
 127     }
 128
 129
 130     while(*cursor != '\0' && !(check_viewport(cursor) && cursor != *document))
 131     {
 132
 133         /* First, we check to see if this line will contain sublines */
 134         bookmark = cursor;
 135         sublines = 0;
 136         while(*cursor != '\n' && *cursor != '\0'
 137               && !(check_viewport(cursor) && cursor != *document))
 138         {
 139             if(*cursor == MULTILINESYM)
 140             {
 141                 sublines = 1;
 142                 break;
 143             }
 144             else if(*cursor == TAGSYM)
 145             {
 146                 /* A ';' directly after a '%' doesn't count */
 147                 cursor ++;
 148
 149                 if(*cursor == '\0')
 150                     break;
 151
 152                 cursor++;
 153             }
 154             else if(*cursor == COMMENTSYM)
 155             {
 156                 skip_comment(&cursor);
 157             }
 158             else
 159             {
 160                 /* Advancing the cursor as normal */
 161                 cursor++;
 162             }
 163         }
 164         cursor = bookmark;
 165
 166         if(!root)
 167             to_write = &root;
 168         else
 169             to_write = &(last->next);
 170
 171         if(sublines)
 172         {
 173             *to_write = skin_parse_sublines(&cursor);
 174             last = *to_write;
 175             if(!last)
 176                 return NULL;
 177         }
 178         else
 179         {
 180
 181             *to_write = skin_parse_line(&cursor);
 182             last = *to_write;
 183             if(!last)
 184                 return NULL;
 185
 186         }
 187
 188         /* Making sure last is at the end */
 189         while(last->next)
 190             last = last->next;
 191
 192         if(*cursor == '\n')
 193         {
 194             cursor++;
 195             skin_line++;
 196         }
 197     }
 198
 199     *document = cursor;
 200
 201     retval->children[retval->children_count - 1] = root;
 202     return retval;
 203
 204 }
 205
 206 /* Auxiliary Parsing Functions */
 207
 208 struct skin_element* skin_parse_line(char**document)
 209 {
 210
 211     return skin_parse_line_optional(document, 0);
 212
 213 }
 214
 215
 216 /*
 217  * If conditional is set to true, then this will break upon encountering
 218  * SEPERATESYM.  This should only be used when parsing a line inside a
 219  * conditional, otherwise just use the wrapper function skin_parse_line()
 220  */
 221 struct skin_element* skin_parse_line_optional(char** document, int conditional)
 222 {
 223     char* cursor = *document;
 224
 225     struct skin_element* root = NULL;
 226     struct skin_element* current = NULL;
 227     struct skin_element* retval = NULL;
 228
 229     /* A wrapper for the line */
 230     retval = skin_alloc_element();
 231     retval->type = LINE;
 232     retval->line = skin_line;
 233     retval->children_count = 1;
 234     retval->children = skin_alloc_children(1);
 235
 236     while(*cursor != '\n' && *cursor != '\0' && *cursor != MULTILINESYM
 237           && !((*cursor == ARGLISTSEPERATESYM
 238                 || *cursor == ARGLISTCLOSESYM
 239                 || *cursor == ENUMLISTSEPERATESYM
 240                 || *cursor == ENUMLISTCLOSESYM)
 241                && conditional)
 242           && !(check_viewport(cursor) && cursor != *document))
 243     {
 244         /* Allocating memory if necessary */
 245         if(root)
 246         {
 247             current->next = skin_alloc_element();
 248             current = current->next;
 249         }
 250         else
 251         {
 252             current = skin_alloc_element();
 253             root = current;
 254         }
 255
 256         /* Parsing the current element */
 257         if(*cursor == TAGSYM && cursor[1] == CONDITIONSYM)
 258         {
 259             if(!skin_parse_conditional(current, &cursor))
 260                 return NULL;
 261         }
 262         else if(*cursor == TAGSYM && !find_escape_character(cursor[1]))
 263         {
 264             if(!skin_parse_tag(current, &cursor))
 265                 return NULL;
 266         }
 267         else if(*cursor == COMMENTSYM)
 268         {
 269             if(!skin_parse_comment(current, &cursor))
 270                 return NULL;
 271         }
 272         else
 273         {
 274             if(!skin_parse_text(current, &cursor, conditional))
 275                 return NULL;
 276         }
 277     }
 278
 279     /* Moving up the calling function's pointer */
 280     *document = cursor;
 281
 282     retval->children[0] = root;
 283     return retval;
 284 }
 285
 286 struct skin_element* skin_parse_sublines(char** document)
 287 {
 288     return skin_parse_sublines_optional(document, 0);
 289 }
 290
 291 struct skin_element* skin_parse_sublines_optional(char** document,
 292                                                   int conditional)
 293 {
 294     struct skin_element* retval;
 295     char* cursor = *document;
 296     int sublines = 1;
 297     int i;
 298
 299     retval = skin_alloc_element();
 300     retval->type = SUBLINES;
 301     retval->next = NULL;
 302     retval->line = skin_line;
 303
 304     /* First we count the sublines */
 305     while(*cursor != '\0' && *cursor != '\n'
 306           && !((*cursor == ARGLISTSEPERATESYM
 307                 || *cursor == ARGLISTCLOSESYM
 308                 || *cursor == ENUMLISTSEPERATESYM
 309                 || *cursor == ENUMLISTCLOSESYM)
 310                && conditional)
 311           && !(check_viewport(cursor) && cursor != *document))
 312     {
 313         if(*cursor == COMMENTSYM)
 314             skip_comment(&cursor);
 315
 316         /* Accounting for escaped subline symbols */
 317         if(*cursor == TAGSYM)
 318         {
 319             cursor++;
 320             if(*cursor == '\0' || *cursor == '\n')
 321                 break;
 322         }
 323
 324         if(*cursor == MULTILINESYM)
 325         {
 326             sublines++;
 327         }
 328
 329         cursor++;
 330     }
 331
 332     /* ...and then we parse them */
 333     retval->children_count = sublines;
 334     retval->children = skin_alloc_children(sublines);
 335
 336     cursor = *document;
 337     for(i = 0; i < sublines; i++)
 338     {
 339         retval->children[i] = skin_parse_line_optional(&cursor, conditional);
 340         skip_whitespace(&cursor);
 341
 342         if(*cursor != MULTILINESYM && i != sublines - 1)
 343         {
 344             skin_error(MULTILINE_EXPECTED);
 345             return NULL;
 346         }
 347         else if(i != sublines - 1)
 348         {
 349             cursor++;
 350         }
 351     }
 352
 353     *document = cursor;
 354
 355     return retval;
 356 }
 357
 358 int skin_parse_tag(struct skin_element* element, char** document)
 359 {
 360
 361     char* cursor = *document + 1;
 362     char* bookmark;
 363
 364     char tag_name[3];
 365     char* tag_args;
 366     struct tag_info *tag;
 367
 368     int num_args = 1;
 369     int i;
 370     int star = 0; /* Flag for the all-or-none option */
 371     int req_args; /* To mark when we enter optional arguments */
 372
 373     int optional = 0;
 374
 375     /* Checking the tag name */
 376     tag_name[0] = cursor[0];
 377     tag_name[1] = cursor[1];
 378     tag_name[2] = '\0';
 379
 380     /* First we check the two characters after the '%', then a single char */
 381     tag = find_tag(tag_name);
 382
 383     if(!tag)
 384     {
 385         tag_name[1] = '\0';
 386         tag = find_tag(tag_name);
 387         cursor++;
 388     }
 389     else
 390     {
 391         cursor += 2;
 392     }
 393
 394     if(!tag)
 395     {
 396         skin_error(ILLEGAL_TAG);
 397         return 0;
 398     }
 399
 400     /* Copying basic tag info */
 401     element->type = TAG;
 402     element->tag = tag;
 403     tag_args = tag->params;
 404     element->line = skin_line;
 405
 406     /* Checking for the * flag */
 407     if(tag_args[0] == '*')
 408     {
 409         star = 1;
 410         tag_args++;
 411     }
 412
 413     /* If this tag has no arguments, we can bail out now */
 414     if(strlen(tag_args) == 0
 415        || (tag_args[0] == '|' && *cursor != ARGLISTOPENSYM)
 416        || (star && *cursor != ARGLISTOPENSYM))
 417     {
 418         *document = cursor;
 419         return 1;
 420     }
 421
 422     /* Checking the number of arguments and allocating args */
 423     if(*cursor != ARGLISTOPENSYM && tag_args[0] != '|')
 424     {
 425         skin_error(ARGLIST_EXPECTED);
 426         return 0;
 427     }
 428     else
 429     {
 430         cursor++;
 431     }
 432
 433     for(bookmark = cursor; *cursor != '\n' && *cursor != '\0' &&
 434         *cursor != ARGLISTCLOSESYM; cursor++)
 435     {
 436         /* Skipping over escaped characters */
 437         if(*cursor == TAGSYM)
 438         {
 439             cursor++;
 440             if(*cursor == '\0')
 441                 break;
 442         }
 443
 444         /* Skipping comments */
 445         if(*cursor == COMMENTSYM)
 446             skip_comment(&cursor);
 447
 448         /* Commas inside of contained lists don't count */
 449         if(*cursor == ARGLISTOPENSYM)
 450             while(*cursor != ARGLISTCLOSESYM && *cursor != '\0')
 451                 cursor++;
 452
 453         if(*cursor == ARGLISTSEPERATESYM)
 454             num_args++;
 455
 456     }
 457     cursor = bookmark; /* Restoring the cursor */
 458     element->params_count = num_args;
 459     element->params = skin_alloc_params(num_args);
 460
 461     /* Now we have to actually parse each argument */
 462     for(i = 0; i < num_args; i++)
 463     {
 464         /* Making sure we haven't run out of arguments */
 465         if(*tag_args == '\0')
 466         {
 467             skin_error(TOO_MANY_ARGS);
 468             return 0;
 469         }
 470
 471         /* Checking for the optional bar */
 472         if(*tag_args == '|')
 473         {
 474             optional = 1;
 475             req_args = i;
 476             tag_args++;
 477         }
 478
 479         /* Scanning the arguments */
 480         skip_whitespace(&cursor);
 481
 482
 483         /* Checking for comments */
 484         if(*cursor == COMMENTSYM)
 485             skip_comment(&cursor);
 486
 487         /* Storing the type code */
 488         element->params[i].type_code = *tag_args;
 489
 490         /* Checking a nullable argument for null */
 491         if(*cursor == DEFAULTSYM && !isdigit(cursor[1]))
 492         {
 493             if(islower(*tag_args))
 494             {
 495                 element->params[i].type = DEFAULT;
 496                 cursor++;
 497             }
 498             else
 499             {
 500                 skin_error(DEFAULT_NOT_ALLOWED);
 501                 return 0;
 502             }
 503         }
 504         else if(tolower(*tag_args) == 'i')
 505         {
 506             /* Scanning an int argument */
 507             if(!isdigit(*cursor) && *cursor != '-')
 508             {
 509                 skin_error(INT_EXPECTED);
 510                 return 0;
 511             }
 512
 513             element->params[i].type = NUMERIC;
 514             element->params[i].data.numeric = scan_int(&cursor);
 515         }
 516         else if(tolower(*tag_args) == 's' || tolower(*tag_args) == 'f')
 517         {
 518             /* Scanning a string argument */
 519             element->params[i].type = STRING;
 520             element->params[i].data.text = scan_string(&cursor);
 521
 522         }
 523         else if(tolower(*tag_args) == 'c')
 524         {
 525             /* Recursively parsing a code argument */
 526             element->params[i].type = CODE;
 527             element->params[i].data.code = skin_parse_code_as_arg(&cursor);
 528             if(!element->params[i].data.code)
 529                 return 0;
 530         }
 531
 532         skip_whitespace(&cursor);
 533
 534         if(*cursor != ARGLISTSEPERATESYM && i < num_args - 1)
 535         {
 536             skin_error(SEPERATOR_EXPECTED);
 537             return 0;
 538         }
 539         else if(*cursor != ARGLISTCLOSESYM && i == num_args - 1)
 540         {
 541             skin_error(CLOSE_EXPECTED);
 542             return 0;
 543         }
 544         else
 545         {
 546             cursor++;
 547         }
 548
 549         tag_args++;
 550
 551         /* Checking for the optional bar */
 552         if(*tag_args == '|')
 553         {
 554             optional = 1;
 555             req_args = i + 1;
 556             tag_args++;
 557         }
 558
 559     }
 560
 561     /* Checking for a premature end */
 562     if(*tag_args != '\0' && !optional)
 563     {
 564         skin_error(INSUFFICIENT_ARGS);
 565         return 0;
 566     }
 567
 568     *document = cursor;
 569
 570     return 1;
 571 }
 572
 573 /*
 574  * If the conditional flag is set true, then parsing text will stop at an
 575  * ARGLISTSEPERATESYM.  Only set that flag when parsing within a conditional
 576  */
 577 int skin_parse_text(struct skin_element* element, char** document,
 578                     int conditional)
 579 {
 580     char* cursor = *document;
 581
 582     int length = 0;
 583
 584     int dest;
 585
 586     /* First figure out how much text we're copying */
 587     while(*cursor != '\0' && *cursor != '\n' && *cursor != MULTILINESYM
 588           && *cursor != COMMENTSYM
 589           && !((*cursor == ARGLISTSEPERATESYM
 590                 || *cursor == ARGLISTCLOSESYM
 591                 || *cursor == ENUMLISTSEPERATESYM
 592                 || *cursor == ENUMLISTCLOSESYM)
 593                && conditional))
 594     {
 595         /* Dealing with possibility of escaped characters */
 596         if(*cursor == TAGSYM)
 597         {
 598             if(find_escape_character(cursor[1]))
 599                 cursor++;
 600             else
 601                 break;
 602         }
 603
 604         length++;
 605         cursor++;
 606     }
 607
 608     cursor = *document;
 609
 610     /* Copying the text into the element struct */
 611     element->type = TEXT;
 612     element->line = skin_line;
 613     element->next = NULL;
 614     element->text = skin_alloc_string(length);
 615
 616     for(dest = 0; dest < length; dest++)
 617     {
 618         /* Advancing cursor if we've encountered an escaped character */
 619         if(*cursor == TAGSYM)
 620             cursor++;
 621
 622         element->text[dest] = *cursor;
 623         cursor++;
 624     }
 625     element->text[length] = '\0';
 626
 627     *document = cursor;
 628
 629     return 1;
 630 }
 631
 632 int skin_parse_conditional(struct skin_element* element, char** document)
 633 {
 634
 635     char* cursor = *document + 1; /* Starting past the "%" */
 636     char* bookmark;
 637     struct skin_element* tag = skin_alloc_element(); /* The tag to evaluate */
 638     int children = 1;
 639     int i;
 640
 641     element->type = CONDITIONAL;
 642     element->line = skin_line;
 643
 644     /* Parsing the tag first */
 645     if(!skin_parse_tag(tag, &cursor))
 646         return 0;
 647
 648     /* Counting the children */
 649     if(*(cursor++) != ENUMLISTOPENSYM)
 650     {
 651         skin_error(ARGLIST_EXPECTED);
 652         return 0;
 653     }
 654     bookmark = cursor;
 655     while(*cursor != ENUMLISTCLOSESYM && *cursor != '\n' && *cursor != '\0')
 656     {
 657         if(*cursor == COMMENTSYM)
 658         {
 659             skip_comment(&cursor);
 660             continue;
 661         }
 662
 663         if(*cursor == TAGSYM)
 664         {
 665             cursor++;
 666             if(*cursor == '\0' || *cursor == '\n')
 667                 break;
 668             cursor++;
 669             continue;
 670         }
 671
 672         if(*cursor == ENUMLISTSEPERATESYM)
 673             children++;
 674
 675         cursor++;
 676     }
 677     cursor = bookmark;
 678
 679     /* Parsing the children */
 680     element->children_count = children + 1; /* Make sure to include the tag */
 681     element->children = skin_alloc_children(children + 1);
 682     element->children[0] = tag;
 683
 684     for(i = 1; i < children + 1; i++)
 685     {
 686         element->children[i] = skin_parse_code_as_arg(&cursor);
 687         skip_whitespace(&cursor);
 688
 689         if(i < children && *cursor != ENUMLISTSEPERATESYM)
 690         {
 691             skin_error(SEPERATOR_EXPECTED);
 692             return 0;
 693         }
 694         else if(i == children && *cursor != ENUMLISTCLOSESYM)
 695         {
 696             skin_error(CLOSE_EXPECTED);
 697             return 0;
 698         }
 699         else
 700         {
 701             cursor++;
 702         }
 703     }
 704
 705     *document = cursor;
 706
 707     return 1;
 708 }
 709
 710 int skin_parse_comment(struct skin_element* element, char** document)
 711 {
 712     char* cursor = *document;
 713
 714     int length;
 715     /*
 716      * Finding the index of the ending newline or null-terminator
 717      * The length of the string of interest doesn't include the leading #, the
 718      * length we need to reserve is the same as the index of the last character
 719      */
 720     for(length = 0; cursor[length] != '\n' && cursor[length] != '\0'; length++);
 721
 722     element->type = COMMENT;
 723     element->line = skin_line;
 724     element->text = skin_alloc_string(length);
 725     /* We copy from one char past cursor to leave out the # */
 726     memcpy((void*)(element->text), (void*)(cursor + 1),
 727            sizeof(char) * (length-1));
 728     element->text[length - 1] = '\0';
 729
 730     if(cursor[length] == '\n')
 731         skin_line++;
 732
 733     *document += (length); /* Move cursor up past # and all text */
 734     if(**document == '\n')
 735         (*document)++;
 736
 737     return 1;
 738 }
 739
 740 struct skin_element* skin_parse_code_as_arg(char** document)
 741 {
 742
 743     int sublines = 0;
 744     char* cursor = *document;
 745
 746     /* Checking for sublines */
 747     while(*cursor != '\n' && *cursor != '\0')
 748     {
 749         if(*cursor == MULTILINESYM)
 750         {
 751             sublines = 1;
 752             break;
 753         }
 754         else if(*cursor == TAGSYM)
 755         {
 756             /* A ';' directly after a '%' doesn't count */
 757             cursor ++;
 758
 759             if(*cursor == '\0')
 760                 break;
 761
 762             cursor++;
 763         }
 764         else
 765         {
 766             /* Advancing the cursor as normal */
 767             cursor++;
 768         }
 769     }
 770
 771     if(sublines)
 772         return skin_parse_sublines_optional(document, 1);
 773     else
 774         return skin_parse_line_optional(document, 1);
 775 }
 776
 777
 778 /* Memory management */
 779 struct skin_element* skin_alloc_element()
 780 {
 781
 782 #if 0
 783
 784     char* retval = &skin_parse_tree[skin_current_block * 4];
 785
 786     int delta = sizeof(struct skin_element) / (sizeof(char) * 4);
 787
 788     /* If one block is partially filled, make sure to advance to the
 789      * next one for the next allocation
 790      */
 791     if(sizeof(struct skin_element) % (sizeof(char) * 4) != 0)
 792         delta++;
 793
 794     skin_current_block += delta;
 795
 796     return (struct skin_element*)retval;
 797
 798 #endif
 799
 800     struct skin_element* retval =  (struct skin_element*)
 801                                    malloc(sizeof(struct skin_element));
 802     retval->next = NULL;
 803     retval->params_count = 0;
 804     retval->children_count = 0;
 805
 806     return retval;
 807
 808 }
 809
 810 struct skin_tag_parameter* skin_alloc_params(int count)
 811 {
 812 #if 0
 813
 814     char* retval = &skin_parse_tree[skin_current_block * 4];
 815
 816     int delta = sizeof(struct skin_tag_parameter) / (sizeof(char) * 4);
 817     delta *= count;
 818
 819     /* Correcting uneven alignment */
 820     if(count * sizeof(struct skin_tag_parameter) % (sizeof(char) * 4) != 0)
 821         delta++;
 822
 823     skin_current_block += delta;
 824
 825     return (struct skin_tag_parameter*) retval;
 826
 827 #endif
 828
 829     return (struct skin_tag_parameter*)malloc(sizeof(struct skin_tag_parameter)
 830                                               * count);
 831
 832 }
 833
 834 char* skin_alloc_string(int length)
 835 {
 836
 837 #if 0
 838     char* retval = &skin_parse_tree[skin_current_block * 4];
 839
 840     /* Checking alignment */
 841     length++; /* Accounting for the null terminator */
 842     int delta = length / 4;
 843     if(length % 4 != 0)
 844         delta++;
 845
 846     skin_current_block += delta;
 847
 848     if(skin_current_block >= SKIN_MAX_MEMORY / 4)
 849         skin_error(MEMORY_LIMIT_EXCEEDED);
 850
 851     return retval;
 852
 853 #endif
 854
 855     return (char*)malloc(sizeof(char) * (length + 1));
 856
 857 }
 858
 859 struct skin_element** skin_alloc_children(int count)
 860 {
 861     return (struct skin_element**) malloc(sizeof(struct skin_element*) * count);
 862 }
 863
 864 void skin_free_tree(struct skin_element* root)
 865 {
 866     int i;
 867
 868     /* First make the recursive call */
 869     if(!root)
 870         return;
 871     skin_free_tree(root->next);
 872
 873     /* Free any text */
 874     if(root->type == TEXT)
 875         free(root->text);
 876
 877     /* Then recursively free any children, before freeing their pointers */
 878     for(i = 0; i < root->children_count; i++)
 879         skin_free_tree(root->children[i]);
 880     if(root->children_count > 0)
 881         free(root->children);
 882
 883     /* Free any parameters, making sure to deallocate strings */
 884     for(i = 0; i < root->params_count; i++)
 885         if(root->params[i].type == STRING)
 886             free(root->params[i].data.text);
 887     if(root->params_count > 0)
 888         free(root->params);
 889
 890     /* Finally, delete root's memory */
 891     free(root);
 892 }