lib/tattc.c

   1 /* tattc.c */
   2
   3 /*
   4  * Copyright (C) 2011-2014 by Werner Lemberg.
   5  *
   6  * This file is part of the ttfautohint library, and may only be used,
   7  * modified, and distributed under the terms given in `COPYING'.  By
   8  * continuing to use, modify, or distribute this file you indicate that you
   9  * have read `COPYING' and understand and accept it fully.
  10  *
  11  * The file `COPYING' mentioned in the previous paragraph is distributed
  12  * with the ttfautohint library.
  13  */
  14
  15
  16 #include "ta.h"
  17
  18
  19 static FT_Error
  20 TA_font_build_TTC_header(FONT* font,
  21                          FT_Byte** header_buf,
  22                          FT_ULong* header_len)
  23 {
  24   SFNT* sfnts = font->sfnts;
  25   FT_Long num_sfnts = font->num_sfnts;
  26
  27   SFNT_Table* tables = font->tables;
  28   FT_ULong num_tables = font->num_tables;
  29
  30   FT_ULong TTF_offset;
  31   FT_ULong DSIG_offset;
  32
  33   FT_Byte* buf;
  34   FT_ULong len;
  35
  36   FT_Long i;
  37   FT_Byte* p;
  38
  39
  40   len = (font->have_DSIG ? 24 : 12) + 4 * num_sfnts;
  41   buf = (FT_Byte*)malloc(len);
  42   if (!buf)
  43     return FT_Err_Out_Of_Memory;
  44
  45   p = buf;
  46
  47   /* TTC ID string */
  48   *(p++) = 't';
  49   *(p++) = 't';
  50   *(p++) = 'c';
  51   *(p++) = 'f';
  52
  53   /* TTC header version */
  54   *(p++) = 0x00;
  55   *(p++) = font->have_DSIG ? 0x02 : 0x01;
  56   *(p++) = 0x00;
  57   *(p++) = 0x00;
  58
  59   /* number of subfonts */
  60   *(p++) = BYTE1(num_sfnts);
  61   *(p++) = BYTE2(num_sfnts);
  62   *(p++) = BYTE3(num_sfnts);
  63   *(p++) = BYTE4(num_sfnts);
  64
  65   /* the first TTF subfont header immediately follows the TTC header */
  66   TTF_offset = len;
  67
  68   /* loop over all subfonts */
  69   for (i = 0; i < num_sfnts; i++)
  70   {
  71     SFNT* sfnt = &sfnts[i];
  72     FT_ULong l;
  73
  74
  75     TA_sfnt_sort_table_info(sfnt, font);
  76     /* only get header length */
  77     (void)TA_sfnt_build_TTF_header(sfnt, font, NULL, &l, 0);
  78
  79     *(p++) = BYTE1(TTF_offset);
  80     *(p++) = BYTE2(TTF_offset);
  81     *(p++) = BYTE3(TTF_offset);
  82     *(p++) = BYTE4(TTF_offset);
  83
  84     TTF_offset += l;
  85   }
  86
  87   /* the first SFNT table immediately follows the subfont TTF headers */
  88   TA_font_compute_table_offsets(font, TTF_offset);
  89
  90   if (font->have_DSIG)
  91   {
  92     /* DSIG tag */
  93     *(p++) = 'D';
  94     *(p++) = 'S';
  95     *(p++) = 'I';
  96     *(p++) = 'G';
  97
  98     /* DSIG length */
  99     *(p++) = 0x00;
 100     *(p++) = 0x00;
 101     *(p++) = 0x00;
 102     *(p++) = 0x08;
 103
 104     /* DSIG offset; in a TTC this is always the last SFNT table */
 105     DSIG_offset = tables[num_tables - 1].offset;
 106
 107     *(p++) = BYTE1(DSIG_offset);
 108     *(p++) = BYTE2(DSIG_offset);
 109     *(p++) = BYTE3(DSIG_offset);
 110     *(p++) = BYTE4(DSIG_offset);
 111   }
 112
 113   *header_buf = buf;
 114   *header_len = len;
 115
 116   return TA_Err_Ok;
 117 }
 118
 119
 120 FT_Error
 121 TA_font_build_TTC(FONT* font)
 122 {
 123   SFNT* sfnts = font->sfnts;
 124   FT_Long num_sfnts = font->num_sfnts;
 125
 126   SFNT_Table* tables;
 127   FT_ULong num_tables;
 128
 129   FT_Byte* DSIG_buf;
 130   SFNT_Table_Info dummy;
 131
 132   FT_Byte* TTC_header_buf;
 133   FT_ULong TTC_header_len;
 134
 135   FT_Byte** TTF_header_bufs = NULL;
 136   FT_ULong* TTF_header_lens = NULL;
 137
 138   FT_ULong offset;
 139   FT_Long i;
 140   FT_ULong j;
 141   FT_Error error;
 142
 143
 144   /* replace an existing `DSIG' table with a dummy */
 145
 146   if (font->have_DSIG)
 147   {
 148     error = TA_table_build_DSIG(&DSIG_buf);
 149     if (error)
 150       return error;
 151
 152     /* in case of success, `DSIG_buf' gets linked */
 153     /* and is eventually freed in `TA_font_unload' */
 154     error = TA_font_add_table(font, &dummy, TTAG_DSIG, DSIG_LEN, DSIG_buf);
 155     if (error)
 156     {
 157       free(DSIG_buf);
 158       return error;
 159     }
 160   }
 161
 162   /* this also computes the SFNT table offsets */
 163   error = TA_font_build_TTC_header(font,
 164                                    &TTC_header_buf, &TTC_header_len);
 165   if (error)
 166     return error;
 167
 168   TTF_header_bufs = (FT_Byte**)calloc(1, num_sfnts * sizeof (FT_Byte*));
 169   if (!TTF_header_bufs)
 170     goto Err;
 171
 172   TTF_header_lens = (FT_ULong*)malloc(num_sfnts * sizeof (FT_ULong));
 173   if (!TTF_header_lens)
 174     goto Err;
 175
 176   for (i = 0; i < num_sfnts; i++)
 177   {
 178     error = TA_sfnt_build_TTF_header(&sfnts[i], font,
 179                                      &TTF_header_bufs[i],
 180                                      &TTF_header_lens[i], 1);
 181     if (error)
 182       goto Err;
 183   }
 184
 185   /* build font */
 186
 187   tables = font->tables;
 188   num_tables = font->num_tables;
 189
 190   /* get font length from last SFNT table array element */
 191   font->out_len = tables[num_tables - 1].offset
 192                   + ((tables[num_tables - 1].len + 3) & ~3);
 193   font->out_buf = (FT_Byte*)malloc(font->out_len);
 194   if (!font->out_buf)
 195   {
 196     error = FT_Err_Out_Of_Memory;
 197     goto Err;
 198   }
 199
 200   memcpy(font->out_buf, TTC_header_buf, TTC_header_len);
 201
 202   offset = TTC_header_len;
 203
 204   for (i = 0; i < num_sfnts; i++)
 205   {
 206     memcpy(font->out_buf + offset,
 207            TTF_header_bufs[i], TTF_header_lens[i]);
 208
 209     offset += TTF_header_lens[i];
 210   }
 211
 212   for (j = 0; j < num_tables; j++)
 213   {
 214     SFNT_Table* table = &tables[j];
 215
 216
 217     /* buffer length is a multiple of 4 */
 218     memcpy(font->out_buf + table->offset,
 219            table->buf, (table->len + 3) & ~3);
 220   }
 221
 222   error = TA_Err_Ok;
 223
 224 Err:
 225   free(TTC_header_buf);
 226   if (TTF_header_bufs)
 227   {
 228     for (i = 0; i < font->num_sfnts; i++)
 229       free(TTF_header_bufs[i]);
 230     free(TTF_header_bufs);
 231   }
 232   free(TTF_header_lens);
 233
 234   return error;
 235 }
 236
 237
 238 /* end of tattc.c */