libs/FBidi.c

   1 /* -*-c-*- */
   2 /* Copyright (C) 2002  Mikhael Goikhman */
   3 /* This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16  */
  17
  18 /*
  19  * FBidi.c - interface to Bidi, we use fribidi implementation here.
  20  * See FBidi.h for some comments on this interface.
  21  */
  22
  23 #include "config.h"
  24
  25 #include "FBidi.h"
  26
  27 #if HAVE_BIDI
  28
  29 #include "safemalloc.h"
  30 #include "BidiJoin.h"
  31 #include <fribidi/fribidi.h>
  32 #include <stdio.h>
  33
  34 Bool FBidiIsApplicable(const char *charset)
  35 {
  36         if (fribidi_parse_charset((char *)charset) ==
  37             FRIBIDI_CHAR_SET_NOT_FOUND)
  38         {
  39                 return False;
  40         }
  41         return True;
  42 }
  43
  44 char *FBidiConvert(
  45         const char *logical_str, const char *charset, int str_len,
  46         Bool *is_rtl, int *out_len, superimpose_char_t *comb_chars,
  47         int *l_to_v)
  48 {
  49         char *visual_str;
  50         FriBidiCharSet fribidi_charset;
  51         FriBidiChar *logical_unicode_str;
  52         FriBidiChar *visual_unicode_str;
  53         FriBidiCharType pbase_dir = FRIBIDI_TYPE_ON;
  54         FriBidiStrIndex *pos_l_to_v;
  55         int i;
  56
  57         if (logical_str == NULL || charset == NULL)
  58         {
  59                 return NULL;
  60         }
  61         if (str_len < 0)
  62         {
  63                 str_len = strlen(logical_str);
  64         }
  65         if (is_rtl != NULL)
  66         {
  67                 *is_rtl = False;
  68         }
  69
  70         fribidi_charset = fribidi_parse_charset((char *)charset);
  71         if (fribidi_charset == FRIBIDI_CHAR_SET_NOT_FOUND)
  72         {
  73                 return NULL;
  74         }
  75
  76         /* it is possible that we allocate a bit more here, if utf-8 */
  77         logical_unicode_str =
  78                 (FriBidiChar *)safemalloc((str_len + 1) * sizeof(FriBidiChar));
  79
  80         /* convert to unicode first */
  81         str_len = fribidi_charset_to_unicode(
  82                 fribidi_charset, (char *)logical_str, str_len,
  83                 logical_unicode_str);
  84
  85         visual_unicode_str =
  86                 (FriBidiChar *)safemalloc((str_len + 1) * sizeof(FriBidiChar));
  87
  88         /* apply bidi algorithm, convert logical string to visual string */
  89         /* also keep track of how characters are reordered here, to reorder
  90            combing characters accordingly */
  91         pos_l_to_v =
  92                 (FriBidiStrIndex *)safemalloc((str_len + 1) *
  93                         sizeof(FriBidiStrIndex));
  94         fribidi_log2vis(
  95                 logical_unicode_str, str_len, &pbase_dir,
  96                 visual_unicode_str, pos_l_to_v, NULL, NULL);
  97
  98         /* remap mapping from logical to visual to "compensate" for BIDI */
  99         if (comb_chars != NULL)
 100         {
 101                 for (i = 0;
 102                     comb_chars[i].c.byte1 != 0 ||
 103                     comb_chars[i].c.byte2 != 0;
 104                     i++)
 105                 {
 106                         /* if input string is zero characters => only
 107                            combining chars, set position to zero */
 108                         comb_chars[i].position =
 109                                 str_len != 0 ?
 110                                 pos_l_to_v[comb_chars[i].position] : 0;
 111                 }
 112         }
 113
 114         if (l_to_v != NULL)
 115         {
 116                 /* values in the previuos mapping gives the position of
 117                    input characters after combining step */
 118                 /* mapping from BIDI conversion maps from the positions in
 119                    the output from combining */
 120                 int orig_len;
 121                 int *l_to_v_temp;
 122                 for (i = 0; l_to_v[i] != -1; i++)
 123                 {
 124                 }
 125                 orig_len = i;
 126                 l_to_v_temp = (int *)safemalloc(orig_len * sizeof(int));
 127                 for (i = 0; i < orig_len; i++)
 128                 {
 129                         l_to_v_temp[i] = pos_l_to_v[l_to_v[i]];
 130                 }
 131                 for (i = 0; i < orig_len; i++)
 132                 {
 133                         l_to_v[i] = l_to_v_temp[i];
 134                 }
 135                 free(l_to_v_temp);
 136         }
 137         free(pos_l_to_v);
 138
 139
 140         /* character shape/join - will get pulled into fribidi with time */
 141         str_len = shape_n_join(visual_unicode_str, str_len);
 142
 143         visual_str = (char *)safemalloc((4 * str_len + 1) * sizeof(char));
 144
 145         /* convert from unicode finally */
 146         *out_len = fribidi_unicode_to_charset(
 147                 fribidi_charset, visual_unicode_str, str_len, visual_str);
 148
 149         if (is_rtl != NULL && pbase_dir == FRIBIDI_TYPE_RTL)
 150         {
 151                 *is_rtl = True;
 152         }
 153
 154         free(logical_unicode_str);
 155         free(visual_unicode_str);
 156         return visual_str;
 157 }
 158
 159 #endif /* HAVE_BIDI */