src/tasfnt.c

   1 /* tasfnt.c */
   2
   3 /*
   4  * Copyright (C) 2011-2012 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->post_idx = MISSING;
  47   sfnt->OS2_idx = MISSING;
  48   sfnt->GPOS_idx = MISSING;
  49
  50   for (i = 0; i < sfnt->num_table_infos; i++)
  51   {
  52     SFNT_Table_Info* table_info = &sfnt->table_infos[i];
  53     FT_ULong tag;
  54     FT_ULong len;
  55     FT_Byte* buf;
  56
  57     FT_ULong buf_len;
  58     FT_ULong j;
  59
  60
  61     *table_info = MISSING;
  62
  63     error = FT_Sfnt_Table_Info(sfnt->face, i, &tag, &len);
  64     if (error)
  65     {
  66       /* this ignores both missing and zero-length tables */
  67       if (error == FT_Err_Table_Missing)
  68         continue;
  69       else
  70         return error;
  71     }
  72
  73     /* ignore tables which we are going to create by ourselves, */
  74     /* or which would become invalid otherwise */
  75     else if (tag == TTAG_fpgm
  76              || tag == TTAG_prep
  77              || tag == TTAG_cvt
  78              || tag == TTAG_hdmx
  79              || tag == TTAG_VDMX
  80              || tag == TTAG_LTSH
  81              || tag == TTAG_gasp)
  82       continue;
  83
  84     else if (tag == TTAG_DSIG)
  85     {
  86       font->have_DSIG = 1;
  87       continue;
  88     }
  89
  90     /* make the allocated buffer length a multiple of 4 */
  91     buf_len = (len + 3) & ~3;
  92     buf = (FT_Byte*)malloc(buf_len);
  93     if (!buf)
  94       return FT_Err_Out_Of_Memory;
  95
  96     /* pad end of buffer with zeros */
  97     buf[buf_len - 1] = 0x00;
  98     buf[buf_len - 2] = 0x00;
  99     buf[buf_len - 3] = 0x00;
 100
 101     /* load table */
 102     error = FT_Load_Sfnt_Table(sfnt->face, tag, 0, buf, &len);
 103     if (error)
 104       goto Err;
 105
 106     /* check whether we already have this table */
 107     for (j = 0; j < font->num_tables; j++)
 108     {
 109       SFNT_Table* table = &font->tables[j];
 110
 111
 112       if (table->tag == tag
 113           && table->len == len
 114           && !memcmp(table->buf, buf, len))
 115         break;
 116     }
 117
 118     if (tag == TTAG_head)
 119       sfnt->head_idx = j;
 120     else if (tag == TTAG_glyf)
 121       sfnt->glyf_idx = j;
 122     else if (tag == TTAG_hmtx)
 123       sfnt->hmtx_idx = j;
 124     else if (tag == TTAG_loca)
 125       sfnt->loca_idx = j;
 126     else if (tag == TTAG_maxp)
 127     {
 128       sfnt->maxp_idx = j;
 129
 130       sfnt->max_components = buf[MAXP_MAX_COMPONENTS_OFFSET] << 8;
 131       sfnt->max_components += buf[MAXP_MAX_COMPONENTS_OFFSET + 1];
 132     }
 133     else if (tag == TTAG_post)
 134       sfnt->post_idx = j;
 135     else if (tag == TTAG_OS2)
 136       sfnt->OS2_idx = j;
 137     else if (tag == TTAG_GPOS)
 138       sfnt->GPOS_idx = j;
 139
 140     if (j == font->num_tables)
 141     {
 142       /* add element to table array if it is missing or different; */
 143       /* in case of success, `buf' gets linked and is eventually */
 144       /* freed in `TA_font_unload' */
 145       error = TA_font_add_table(font, table_info, tag, len, buf);
 146       if (error)
 147         goto Err;
 148     }
 149     else
 150     {
 151       /* reuse existing SFNT table */
 152       free(buf);
 153       *table_info = j;
 154     }
 155     continue;
 156
 157   Err:
 158     free(buf);
 159     return error;
 160   }
 161
 162   /* no (non-empty) `glyf', `loca', `head', or `maxp' table; */
 163   /* this can't be a valid TTF with outlines */
 164   if (sfnt->glyf_idx == MISSING
 165       || sfnt->loca_idx == MISSING
 166       || sfnt->head_idx == MISSING
 167       || sfnt->maxp_idx == MISSING)
 168     return FT_Err_Invalid_Argument;
 169
 170   return TA_Err_Ok;
 171 }
 172
 173 /* end of tasfnt.c */