src/tasfnt.c

   1 /* tasfnt.c */
   2
   3 /*
   4  * Copyright (C) 2011 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 FT_Error
  20 TA_sfnt_split_into_SFNT_tables(SFNT* sfnt,
  21                                FONT* font)
  22 {
  23   FT_Error error;
  24   FT_ULong i;
  25
  26
  27   /* basic check whether font is a TTF or TTC */
  28   if (!FT_IS_SFNT(sfnt->face))
  29     return FT_Err_Invalid_Argument;
  30
  31   error = FT_Sfnt_Table_Info(sfnt->face, 0, NULL, &sfnt->num_table_infos);
  32   if (error)
  33     return error;
  34
  35   sfnt->table_infos = (SFNT_Table_Info*)malloc(sfnt->num_table_infos
  36                                                * sizeof (SFNT_Table_Info));
  37   if (!sfnt->table_infos)
  38     return FT_Err_Out_Of_Memory;
  39
  40   /* collect SFNT tables and trace some of them */
  41   sfnt->glyf_idx = MISSING;
  42   sfnt->loca_idx = MISSING;
  43   sfnt->head_idx = MISSING;
  44   sfnt->hmtx_idx = MISSING;
  45   sfnt->maxp_idx = MISSING;
  46   sfnt->OS2_idx = MISSING;
  47   sfnt->GPOS_idx = MISSING;
  48
  49   for (i = 0; i < sfnt->num_table_infos; i++)
  50   {
  51     SFNT_Table_Info* table_info = &sfnt->table_infos[i];
  52     FT_ULong tag;
  53     FT_ULong len;
  54     FT_Byte* buf;
  55
  56     FT_ULong buf_len;
  57     FT_ULong j;
  58
  59
  60     *table_info = MISSING;
  61
  62     error = FT_Sfnt_Table_Info(sfnt->face, i, &tag, &len);
  63     if (error)
  64     {
  65       /* this ignores both missing and zero-length tables */
  66       if (error == FT_Err_Table_Missing)
  67         continue;
  68       else
  69         return error;
  70     }
  71
  72     /* ignore tables which we are going to create by ourselves, */
  73     /* or which would become invalid otherwise */
  74     else if (tag == TTAG_fpgm
  75              || tag == TTAG_prep
  76              || tag == TTAG_cvt
  77              || tag == TTAG_hdmx
  78              || tag == TTAG_VDMX
  79              || tag == TTAG_LTSH
  80              || tag == TTAG_gasp)
  81       continue;
  82
  83     else if (tag == TTAG_DSIG)
  84     {
  85       font->have_DSIG = 1;
  86       continue;
  87     }
  88
  89     /* make the allocated buffer length a multiple of 4 */
  90     buf_len = (len + 3) & ~3;
  91     buf = (FT_Byte*)malloc(buf_len);
  92     if (!buf)
  93       return FT_Err_Out_Of_Memory;
  94
  95     /* pad end of buffer with zeros */
  96     buf[buf_len - 1] = 0x00;
  97     buf[buf_len - 2] = 0x00;
  98     buf[buf_len - 3] = 0x00;
  99
 100     /* load table */
 101     error = FT_Load_Sfnt_Table(sfnt->face, tag, 0, buf, &len);
 102     if (error)
 103       goto Err;
 104
 105     /* check whether we already have this table */
 106     for (j = 0; j < font->num_tables; j++)
 107     {
 108       SFNT_Table* table = &font->tables[j];
 109
 110
 111       if (table->tag == tag
 112           && table->len == len
 113           && !memcmp(table->buf, buf, len))
 114         break;
 115     }
 116
 117     if (tag == TTAG_head)
 118       sfnt->head_idx = j;
 119     else if (tag == TTAG_glyf)
 120       sfnt->glyf_idx = j;
 121     else if (tag == TTAG_hmtx)
 122       sfnt->hmtx_idx = j;
 123     else if (tag == TTAG_loca)
 124       sfnt->loca_idx = j;
 125     else if (tag == TTAG_maxp)
 126     {
 127       sfnt->maxp_idx = j;
 128
 129       sfnt->max_components = buf[MAXP_MAX_COMPONENTS_OFFSET] << 8;
 130       sfnt->max_components += buf[MAXP_MAX_COMPONENTS_OFFSET + 1];
 131     }
 132     else if (tag == TTAG_OS2)
 133       sfnt->OS2_idx = j;
 134     else if (tag == TTAG_GPOS)
 135       sfnt->GPOS_idx = j;
 136
 137     if (j == font->num_tables)
 138     {
 139       /* add element to table array if it is missing or different; */
 140       /* in case of success, `buf' gets linked and is eventually */
 141       /* freed in `TA_font_unload' */
 142       error = TA_font_add_table(font, table_info, tag, len, buf);
 143       if (error)
 144         goto Err;
 145     }
 146     else
 147     {
 148       /* reuse existing SFNT table */
 149       free(buf);
 150       *table_info = j;
 151     }
 152     continue;
 153
 154   Err:
 155     free(buf);
 156     return error;
 157   }
 158
 159   /* no (non-empty) `glyf', `loca', `head', or `maxp' table; */
 160   /* this can't be a valid TTF with outlines */
 161   if (sfnt->glyf_idx == MISSING
 162       || sfnt->loca_idx == MISSING
 163       || sfnt->head_idx == MISSING
 164       || sfnt->maxp_idx == MISSING)
 165     return FT_Err_Invalid_Argument;
 166
 167   return TA_Err_Ok;
 168 }
 169
 170 /* end of tasfnt.c */