pith/escapes.c

   1 #if !defined(lint) && !defined(DOS)
   2 static char rcsid[] = "$Id: escapes.c 761 2007-10-23 22:35:18Z hubert@u.washington.edu $";
   3 #endif
   4
   5 /*
   6  * ========================================================================
   7  * Copyright 2013-2017 Eduardo Chappa
   8  * Copyright 2006 University of Washington
   9  *
  10  * Licensed under the Apache License, Version 2.0 (the "License");
  11  * you may not use this file except in compliance with the License.
  12  * You may obtain a copy of the License at
  13  *
  14  *     http://www.apache.org/licenses/LICENSE-2.0
  15  *
  16  * ========================================================================
  17  */
  18
  19 /*======================================================================
  20
  21      escapes.c
  22      Implements known escape code matching
  23
  24   ====*/
  25
  26
  27 #include "../pith/headers.h"
  28 #include "../pith/escapes.h"
  29
  30
  31
  32 /*------------------------------------------------------------------
  33    This list of known escape sequences is taken from RFC's 1486 and 1554
  34    and draft-apng-cc-encoding, and the X11R5 source with only a remote
  35    understanding of what this all means...
  36
  37    NOTE: if the length of these should extend beyond 4 chars, fix
  38          MAX_ESC_LEN in filter.c
  39   ----*/
  40 #ifdef  _WINDOWS
  41 static char *known_escapes[] = {
  42     "(B",  "(J",  "$@",  "$B",                  /* RFC 1468 */
  43     "(H",
  44     NULL};
  45 #else
  46 static char *known_escapes[] = {
  47     "(B",  "(J",  "$@",  "$B",                  /* RFC 1468 */
  48     "(H",
  49     "$A",  "$(C", "$(D", ".A",  ".F",           /* added by RFC 1554 */
  50     "$)C", "$)A", "$*E", "$*X",                 /* those in apng-draft */
  51     "$+G", "$+H", "$+I", "$+J", "$+K",
  52     "$+L", "$+M",
  53     ")I",   "-A",  "-B",  "-C",  "-D",          /* codes form X11R5 source */
  54     "-F",   "-G",  "-H",   "-L",  "-M",
  55     "-$(A", "$(B", "$)B", "$)D",
  56     NULL};
  57 #endif
  58
  59
  60 int
  61 match_escapes(char *esc_seq)
  62 {
  63     char **p;
  64     int    n;
  65
  66     for(p = known_escapes; *p && strncmp(esc_seq, *p, n = strlen(*p)); p++)
  67       ;
  68
  69     return(*p ? n + 1 : 0);
  70 }