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_newline(struct skin_element* element, char** document);
  53 int skin_parse_comment(struct skin_element* element, char** document);
  54 struct skin_element* skin_parse_code_as_arg(char** document);
  55
  56 struct skin_element* skin_parse(char* document)
  57 {
  58
  59     struct skin_element* root = NULL;
  60     struct skin_element* last = NULL;
  61
  62     struct skin_element** to_write = 0;
  63
  64     char* cursor = document; /* Keeps track of location in the document */
  65
  66     skin_line = 1;
  67
  68     while(*cursor != '\0')
  69     {
  70
  71         if(!root)
  72             to_write = &root;
  73         else
  74             to_write = &(last->next);
  75
  76
  77         *to_write = skin_parse_viewport(&cursor);
  78         last = *to_write;
  79         if(!last)
  80             return NULL;
  81
  82         /* Making sure last is at the end */
  83         while(last->next)
  84             last = last->next;
  85
  86     }
  87
  88     return root;
  89
  90 }
  91
  92 struct skin_element* skin_parse_viewport(char** document)
  93 {
  94
  95     struct skin_element* root = NULL;
  96     struct skin_element* last = NULL;
  97     struct skin_element* retval = NULL;
  98
  99     retval = skin_alloc_element();
 100     retval->type = VIEWPORT;
 101     retval->children_count = 1;
 102     retval->line = skin_line;
 103
 104     struct skin_element** to_write = 0;
 105
 106     char* cursor = *document; /* Keeps track of location in the document */
 107     char* bookmark; /* Used when we need to look ahead */
 108
 109     int sublines = 0; /* Flag for parsing sublines */
 110
 111     /* Parsing out the viewport tag if there is one */
 112     if(check_viewport(cursor))
 113     {
 114         retval->children_count = 2;
 115         retval->children = skin_alloc_children(2);
 116         retval->children[0] = skin_alloc_element();
 117         skin_parse_tag(retval->children[0], &cursor);
 118     }
 119     else
 120     {
 121         retval->children_count = 1;
 122         retval->children = skin_alloc_children(1);
 123     }
 124
 125
 126     while(*cursor != '\0' && !(check_viewport(cursor) && cursor != *document))
 127     {
 128
 129         /* First, we check to see if this line will contain sublines */
 130         bookmark = cursor;
 131         sublines = 0;
 132         while(*cursor != '\n' && *cursor != '\0'
 133               && !(check_viewport(cursor) && cursor != *document))
 134         {
 135             if(*cursor == MULTILINESYM)
 136             {
 137                 sublines = 1;
 138                 break;
 139             }
 140             else if(*cursor == TAGSYM)
 141             {
 142                 /* A ';' directly after a '%' doesn't count */
 143                 cursor ++;
 144
 145                 if(*cursor == '\0')
 146                     break;
 147
 148                 cursor++;
 149             }
 150             else if(*cursor == COMMENTSYM)
 151             {
 152                 skip_comment(&cursor);
 153             }
 154             else
 155             {
 156                 /* Advancing the cursor as normal */
 157                 cursor++;
 158             }
 159         }
 160         cursor = bookmark;
 161
 162         if(!root)
 163             to_write = &root;
 164         else
 165             to_write = &(last->next);
 166
 167         if(*cursor == '\n')
 168         {
 169             *to_write = skin_alloc_element();
 170             skin_parse_newline(*to_write, &cursor);
 171             if(!last)
 172                 return NULL;
 173         }
 174         else if(sublines)
 175         {
 176             *to_write = skin_parse_sublines(&cursor);
 177             last = *to_write;
 178             if(!last)
 179                 return NULL;
 180         }
 181         else
 182         {
 183
 184             *to_write = skin_parse_line(&cursor);
 185             last = *to_write;
 186             if(!last)
 187                 return NULL;
 188
 189         }
 190
 191         /* Making sure last is at the end */
 192         while(last->next)
 193             last = last->next;
 194
 195     }
 196
 197     *document = cursor;
 198
 199     retval->children[retval->children_count - 1] = root;
 200     return retval;
 201
 202 }
 203
 204 /* Auxiliary Parsing Functions */
 205
 206 struct skin_element* skin_parse_line(char**document)
 207 {
 208
 209     return skin_parse_line_optional(document, 0);
 210
 211 }
 212
 213
 214 /*
 215  * If conditional is set to true, then this will break upon encountering
 216  * SEPERATESYM.  This should only be used when parsing a line inside a
 217  * conditional, otherwise just use the wrapper function skin_parse_line()
 218  */
 219 struct skin_element* skin_parse_line_optional(char** document, int conditional)
 220 {
 221     char* cursor = *document;
 222
 223     struct skin_element* root = NULL;
 224     struct skin_element* current = NULL;
 225     struct skin_element* retval = NULL;
 226
 227     /* A wrapper for the line */
 228     retval = skin_alloc_element();
 229     retval->type = LINE;
 230     retval->line = skin_line;
 231     retval->children_count = 1;
 232     retval->children = skin_alloc_children(1);
 233
 234     while(*cursor != '\n' && *cursor != '\0' && *cursor != MULTILINESYM
 235           && !((*cursor == ARGLISTSEPERATESYM
 236                 || *cursor == ARGLISTCLOSESYM
 237                 || *cursor == ENUMLISTSEPERATESYM
 238                 || *cursor == ENUMLISTCLOSESYM)
 239                && conditional)
 240           && !(check_viewport(cursor) && cursor != *document))
 241     {
 242         /* Allocating memory if necessary */
 243         if(root)
 244         {
 245             current->next = skin_alloc_element();
 246             current = current->next;
 247         }
 248         else
 249         {
 250             current = skin_alloc_element();
 251             root = current;
 252         }
 253
 254         /* Parsing the current element */
 255         if(*cursor == TAGSYM && cursor[1] == CONDITIONSYM)
 256         {
 257             if(!skin_parse_conditional(current, &cursor))
 258                 return NULL;
 259         }
 260         else if(*cursor == TAGSYM)
 261         {
 262             if(!skin_parse_tag(current, &cursor))
 263                 return NULL;
 264         }
 265         else if(*cursor == COMMENTSYM)
 266         {
 267             if(!skin_parse_comment(current, &cursor))
 268                 return NULL;
 269         }
 270         else
 271         {
 272             if(!skin_parse_text(current, &cursor, conditional))
 273                 return NULL;
 274         }
 275     }
 276
 277     /* Moving up the calling function's pointer */
 278     *document = cursor;
 279
 280     retval->children[0] = root;
 281     return retval;
 282 }
 283
 284 struct skin_element* skin_parse_sublines(char** document)
 285 {
 286     return skin_parse_sublines_optional(document, 0);
 287 }
 288
 289 struct skin_element* skin_parse_sublines_optional(char** document,
 290                                                   int conditional)
 291 {
 292     struct skin_element* retval;
 293     char* cursor = *document;
 294     int sublines = 1;
 295     int i;
 296
 297     retval = skin_alloc_element();
 298     retval->type = SUBLINES;
 299     retval->next = NULL;
 300     retval->line = skin_line;
 301
 302     /* First we count the sublines */
 303     while(*cursor != '\0' && *cursor != '\n'
 304           && !((*cursor == ARGLISTSEPERATESYM
 305                 || *cursor == ARGLISTCLOSESYM
 306                 || *cursor == ENUMLISTSEPERATESYM
 307                 || *cursor == ENUMLISTCLOSESYM)
 308                && conditional)
 309           && !(check_viewport(cursor) && cursor != *document))
 310     {
 311         if(*cursor == COMMENTSYM)
 312             skip_comment(&cursor);
 313
 314         /* Accounting for escaped subline symbols */
 315         if(*cursor == TAGSYM)
 316         {
 317             cursor++;
 318             if(*cursor == '\0' || *cursor == '\n')
 319                 break;
 320         }
 321
 322         if(*cursor == MULTILINESYM)
 323         {
 324             sublines++;
 325         }
 326
 327         cursor++;
 328     }
 329
 330     /* ...and then we parse them */
 331     retval->children_count = sublines;
 332     retval->children = skin_alloc_children(sublines);
 333
 334     cursor = *document;
 335     for(i = 0; i < sublines; i++)
 336     {
 337         retval->children[i] = skin_parse_line_optional(&cursor, conditional);
 338         skip_whitespace(&cursor);
 339
 340         if(*cursor != MULTILINESYM && i != sublines - 1)
 341         {
 342             skin_error(MULTILINE_EXPECTED);
 343             return NULL;
 344         }
 345         else if(i != sublines - 1)
 346         {
 347             cursor++;
 348         }
 349     }
 350
 351     *document = cursor;
 352
 353     return retval;
 354 }
 355
 356 int skin_parse_tag(struct skin_element* element, char** document)
 357 {
 358
 359     char* cursor = *document + 1;
 360     char* bookmark;
 361
 362     char tag_name[3];
 363     char* tag_args;
 364     struct tag_info *tag;
 365
 366     int num_args = 1;
 367     int i;
 368     int star = 0; /* Flag for the all-or-none option */
 369     int req_args; /* To mark when we enter optional arguments */
 370
 371     int optional = 0;
 372
 373     /* Checking the tag name */
 374     tag_name[0] = cursor[0];
 375     tag_name[1] = cursor[1];
 376     tag_name[2] = '\0';
 377
 378     /* First we check the two characters after the '%', then a single char */
 379     tag = find_tag(tag_name);
 380
 381     if(!tag)
 382     {
 383         tag_name[1] = '\0';
 384         tag = find_tag(tag_name);
 385         cursor++;
 386     }
 387     else
 388     {
 389         cursor += 2;
 390     }
 391
 392     if(!tag)
 393     {
 394         skin_error(ILLEGAL_TAG);
 395         return 0;
 396     }
 397
 398     /* Copying basic tag info */
 399     element->type = TAG;
 400     element->tag = tag;
 401     tag_args = tag->params;
 402     element->line = skin_line;
 403
 404     /* Checking for the * flag */
 405     if(tag_args[0] == '*')
 406     {
 407         star = 1;
 408         tag_args++;
 409     }
 410
 411     /* If this tag has no arguments, we can bail out now */
 412     if(strlen(tag_args) == 0
 413        || (tag_args[0] == '|' && *cursor != ARGLISTOPENSYM))
 414     {
 415         *document = cursor;
 416         return 1;
 417     }
 418
 419     /* Checking the number of arguments and allocating args */
 420     if(*cursor != ARGLISTOPENSYM && tag_args[0] != '|')
 421     {
 422         skin_error(ARGLIST_EXPECTED);
 423         return 0;
 424     }
 425     else
 426     {
 427         cursor++;
 428     }
 429
 430     for(bookmark = cursor; *cursor != '\n' && *cursor != '\0' &&
 431         *cursor != ARGLISTCLOSESYM; cursor++)
 432     {
 433         /* Skipping over escaped characters */
 434         if(*cursor == TAGSYM)
 435         {
 436             cursor++;
 437             if(*cursor == '\0')
 438                 break;
 439         }
 440
 441         /* Skipping comments */
 442         if(*cursor == COMMENTSYM)
 443             skip_comment(&cursor);
 444
 445         /* Commas inside of contained lists don't count */
 446         if(*cursor == ARGLISTOPENSYM)
 447             while(*cursor != ARGLISTCLOSESYM && *cursor != '\0')
 448                 cursor++;
 449
 450         if(*cursor == ARGLISTSEPERATESYM)
 451             num_args++;
 452
 453     }
 454     cursor = bookmark; /* Restoring the cursor */
 455     element->params_count = num_args;
 456     element->params = skin_alloc_params(num_args);
 457
 458     /* Now we have to actually parse each argument */
 459     for(i = 0; i < num_args; i++)
 460     {
 461         /* Making sure we haven't run out of arguments */
 462         if(*tag_args == '\0')
 463         {
 464             skin_error(TOO_MANY_ARGS);
 465             return 0;
 466         }
 467
 468         /* Checking for the optional bar */
 469         if(*tag_args == '|')
 470         {
 471             optional = 1;
 472             req_args = i;
 473             tag_args++;
 474         }
 475
 476         /* Scanning the arguments */
 477         skip_whitespace(&cursor);
 478
 479
 480         /* Checking for comments */
 481         if(*cursor == COMMENTSYM)
 482             skip_comment(&cursor);
 483
 484         /* Checking a nullable argument for null */
 485         if(*cursor == DEFAULTSYM)
 486         {
 487             if(islower(*tag_args))
 488             {
 489                 element->params[i].type = DEFAULT;
 490                 cursor++;
 491             }
 492             else
 493             {
 494                 skin_error(DEFAULT_NOT_ALLOWED);
 495                 return 0;
 496             }
 497         }
 498         else if(tolower(*tag_args) == 'i')
 499         {
 500             /* Scanning an int argument */
 501             if(!isdigit(*cursor))
 502             {
 503                 skin_error(INT_EXPECTED);
 504                 return 0;
 505             }
 506
 507             element->params[i].type = NUMERIC;
 508             element->params[i].data.numeric = scan_int(&cursor);
 509         }
 510         else if(tolower(*tag_args) == 's' || tolower(*tag_args) == 'f')
 511         {
 512             /* Scanning a string argument */
 513             element->params[i].type = STRING;
 514             element->params[i].data.text = scan_string(&cursor);
 515
 516         }
 517         else if(tolower(*tag_args) == 'c')
 518         {
 519             /* Recursively parsing a code argument */
 520             element->params[i].type = CODE;
 521             element->params[i].data.code = skin_parse_code_as_arg(&cursor);
 522             if(!element->params[i].data.code)
 523                 return 0;
 524         }
 525
 526         skip_whitespace(&cursor);
 527
 528         if(*cursor != ARGLISTSEPERATESYM && i < num_args - 1)
 529         {
 530             skin_error(SEPERATOR_EXPECTED);
 531             return 0;
 532         }
 533         else if(*cursor != ARGLISTCLOSESYM && i == num_args - 1)
 534         {
 535             skin_error(CLOSE_EXPECTED);
 536             return 0;
 537         }
 538         else
 539         {
 540             cursor++;
 541         }
 542
 543         tag_args++;
 544
 545         /* Checking for the optional bar */
 546         if(*tag_args == '|')
 547         {
 548             optional = 1;
 549             req_args = i + 1;
 550             tag_args++;
 551         }
 552
 553     }
 554
 555     /* Checking for a premature end */
 556     if(*tag_args != '\0' && !(optional && (!star || num_args == req_args)))
 557     {
 558         skin_error(INSUFFICIENT_ARGS);
 559         return 0;
 560     }
 561
 562     *document = cursor;
 563
 564     return 1;
 565 }
 566
 567 /*
 568  * If the conditional flag is set true, then parsing text will stop at an
 569  * ARGLISTSEPERATESYM.  Only set that flag when parsing within a conditional
 570  */
 571 int skin_parse_text(struct skin_element* element, char** document,
 572                     int conditional)
 573 {
 574     char* cursor = *document;
 575
 576     int length = 0;
 577
 578     int dest;
 579
 580     /* First figure out how much text we're copying */
 581     while(*cursor != '\0' && *cursor != '\n' && *cursor != MULTILINESYM
 582           && *cursor != COMMENTSYM
 583           && !((*cursor == ARGLISTSEPERATESYM
 584                 || *cursor == ARGLISTCLOSESYM
 585                 || *cursor == ENUMLISTSEPERATESYM
 586                 || *cursor == ENUMLISTCLOSESYM)
 587                && conditional))
 588     {
 589         /* Dealing with possibility of escaped characters */
 590         if(*cursor == TAGSYM)
 591         {
 592             if(find_escape_character(cursor[1]))
 593                 cursor++;
 594             else
 595                 break;
 596         }
 597
 598         length++;
 599         cursor++;
 600     }
 601
 602     cursor = *document;
 603
 604     /* Copying the text into the element struct */
 605     element->type = TEXT;
 606     element->line = skin_line;
 607     element->next = NULL;
 608     element->text = skin_alloc_string(length);
 609
 610     for(dest = 0; dest < length; dest++)
 611     {
 612         /* Advancing cursor if we've encountered an escaped character */
 613         if(*cursor == TAGSYM)
 614             cursor++;
 615
 616         element->text[dest] = *cursor;
 617         cursor++;
 618     }
 619     element->text[length] = '\0';
 620
 621     *document = cursor;
 622
 623     return 1;
 624 }
 625
 626 int skin_parse_conditional(struct skin_element* element, char** document)
 627 {
 628
 629     char* cursor = *document + 1; /* Starting past the "%" */
 630     char* bookmark;
 631     struct skin_element* tag = skin_alloc_element(); /* The tag to evaluate */
 632     int children = 1;
 633     int i;
 634
 635     element->type = CONDITIONAL;
 636     element->line = skin_line;
 637
 638     /* Parsing the tag first */
 639     if(!skin_parse_tag(tag, &cursor))
 640         return 0;
 641
 642     /* Counting the children */
 643     if(*(cursor++) != ENUMLISTOPENSYM)
 644     {
 645         skin_error(ARGLIST_EXPECTED);
 646         return 0;
 647     }
 648     bookmark = cursor;
 649     while(*cursor != ENUMLISTCLOSESYM && *cursor != '\n' && *cursor != '\0')
 650     {
 651         if(*cursor == COMMENTSYM)
 652         {
 653             skip_comment(&cursor);
 654             continue;
 655         }
 656
 657         if(*cursor == TAGSYM)
 658         {
 659             cursor++;
 660             if(*cursor == '\0' || *cursor == '\n')
 661                 break;
 662             cursor++;
 663             continue;
 664         }
 665
 666         if(*cursor == ENUMLISTSEPERATESYM)
 667             children++;
 668
 669         cursor++;
 670     }
 671     cursor = bookmark;
 672
 673     /* Parsing the children */
 674     element->children_count = children + 1; /* Make sure to include the tag */
 675     element->children = skin_alloc_children(children + 1);
 676     element->children[0] = tag;
 677
 678     for(i = 1; i < children + 1; i++)
 679     {
 680         element->children[i] = skin_parse_code_as_arg(&cursor);
 681         skip_whitespace(&cursor);
 682
 683         if(i < children && *cursor != ENUMLISTSEPERATESYM)
 684         {
 685             skin_error(SEPERATOR_EXPECTED);
 686             return 0;
 687         }
 688         else if(i == children && *cursor != ENUMLISTCLOSESYM)
 689         {
 690             skin_error(CLOSE_EXPECTED);
 691             return 0;
 692         }
 693         else
 694         {
 695             cursor++;
 696         }
 697     }
 698
 699     *document = cursor;
 700
 701     return 1;
 702 }
 703
 704 int skin_parse_newline(struct skin_element* element, char** document)
 705 {
 706
 707     char* cursor = *document;
 708     if(*cursor != '\n')
 709     {
 710         skin_error(NEWLINE_EXPECTED);
 711         return 0;
 712     }
 713     cursor++;
 714
 715     /* Assembling a skin_element struct for a newline */
 716     element->type = NEWLINE;
 717     element->line = skin_line;
 718     skin_line++;
 719     element->next = NULL;
 720
 721     *document = cursor;
 722
 723     return 1;
 724 }
 725
 726 int skin_parse_comment(struct skin_element* element, char** document)
 727 {
 728     char* cursor = *document;
 729
 730     int length;
 731     /*
 732      * Finding the index of the ending newline or null-terminator
 733      * The length of the string of interest doesn't include the leading #, the
 734      * length we need to reserve is the same as the index of the last character
 735      */
 736     for(length = 0; cursor[length] != '\n' && cursor[length] != '\0'; length++);
 737
 738     element->type = COMMENT;
 739     element->line = skin_line;
 740     element->text = skin_alloc_string(length);
 741     /* We copy from one char past cursor to leave out the # */
 742     memcpy((void*)(element->text), (void*)(cursor + 1), sizeof(char) * length);
 743     element->text[length] = '\0';
 744
 745     if(cursor[length] == '\n')
 746         skin_line++;
 747
 748     *document += (length + 1); /* Move cursor up past # and all text */
 749
 750     return 1;
 751 }
 752
 753 struct skin_element* skin_parse_code_as_arg(char** document)
 754 {
 755
 756     int sublines = 0;
 757     char* cursor = *document;
 758
 759     /* Checking for sublines */
 760     while(*cursor != '\n' && *cursor != '\0')
 761     {
 762         if(*cursor == MULTILINESYM)
 763         {
 764             sublines = 1;
 765             break;
 766         }
 767         else if(*cursor == TAGSYM)
 768         {
 769             /* A ';' directly after a '%' doesn't count */
 770             cursor ++;
 771
 772             if(*cursor == '\0')
 773                 break;
 774
 775             cursor++;
 776         }
 777         else
 778         {
 779             /* Advancing the cursor as normal */
 780             cursor++;
 781         }
 782     }
 783
 784     if(sublines)
 785         return skin_parse_sublines_optional(document, 1);
 786     else
 787         return skin_parse_line_optional(document, 1);
 788 }
 789
 790
 791 /* Memory management */
 792 struct skin_element* skin_alloc_element()
 793 {
 794
 795 #if 0
 796
 797     char* retval = &skin_parse_tree[skin_current_block * 4];
 798
 799     int delta = sizeof(struct skin_element) / (sizeof(char) * 4);
 800
 801     /* If one block is partially filled, make sure to advance to the
 802      * next one for the next allocation
 803      */
 804     if(sizeof(struct skin_element) % (sizeof(char) * 4) != 0)
 805         delta++;
 806
 807     skin_current_block += delta;
 808
 809     return (struct skin_element*)retval;
 810
 811 #endif
 812
 813     struct skin_element* retval =  (struct skin_element*)
 814                                    malloc(sizeof(struct skin_element));
 815     retval->next = NULL;
 816     retval->params_count = 0;
 817     retval->children_count = 0;
 818
 819     return retval;
 820
 821 }
 822
 823 struct skin_tag_parameter* skin_alloc_params(int count)
 824 {
 825 #if 0
 826
 827     char* retval = &skin_parse_tree[skin_current_block * 4];
 828
 829     int delta = sizeof(struct skin_tag_parameter) / (sizeof(char) * 4);
 830     delta *= count;
 831
 832     /* Correcting uneven alignment */
 833     if(count * sizeof(struct skin_tag_parameter) % (sizeof(char) * 4) != 0)
 834         delta++;
 835
 836     skin_current_block += delta;
 837
 838     return (struct skin_tag_parameter*) retval;
 839
 840 #endif
 841
 842     return (struct skin_tag_parameter*)malloc(sizeof(struct skin_tag_parameter)
 843                                               * count);
 844
 845 }
 846
 847 char* skin_alloc_string(int length)
 848 {
 849
 850 #if 0
 851     char* retval = &skin_parse_tree[skin_current_block * 4];
 852
 853     /* Checking alignment */
 854     length++; /* Accounting for the null terminator */
 855     int delta = length / 4;
 856     if(length % 4 != 0)
 857         delta++;
 858
 859     skin_current_block += delta;
 860
 861     if(skin_current_block >= SKIN_MAX_MEMORY / 4)
 862         skin_error(MEMORY_LIMIT_EXCEEDED);
 863
 864     return retval;
 865
 866 #endif
 867
 868     return (char*)malloc(sizeof(char) * (length + 1));
 869
 870 }
 871
 872 struct skin_element** skin_alloc_children(int count)
 873 {
 874     return (struct skin_element**) malloc(sizeof(struct skin_element*) * count);
 875 }
 876
 877 void skin_free_tree(struct skin_element* root)
 878 {
 879     int i;
 880
 881     /* First make the recursive call */
 882     if(!root)
 883         return;
 884     skin_free_tree(root->next);
 885
 886     /* Free any text */
 887     if(root->type == TEXT)
 888         free(root->text);
 889
 890     /* Then recursively free any children, before freeing their pointers */
 891     for(i = 0; i < root->children_count; i++)
 892         skin_free_tree(root->children[i]);
 893     if(root->children_count > 0)
 894         free(root->children);
 895
 896     /* Free any parameters, making sure to deallocate strings */
 897     for(i = 0; i < root->params_count; i++)
 898         if(root->params[i].type == STRING)
 899             free(root->params[i].data.text);
 900     if(root->params_count > 0)
 901         free(root->params);
 902
 903     /* Finally, delete root's memory */
 904     free(root);
 905 }