lib/tasfnt.c

   1 /* tasfnt.c */
   2
   3 /*
   4  * Copyright (C) 2011-2022 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 TA_Err_Invalid_Font_Type;
  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->name_idx = MISSING;
  47   sfnt->post_idx = MISSING;
  48   sfnt->OS2_idx = MISSING;
  49   sfnt->GPOS_idx = MISSING;
  50
  51   for (i = 0; i < sfnt->num_table_infos; i++)
  52   {
  53     SFNT_Table_Info* table_info = &sfnt->table_infos[i];
  54     FT_ULong tag;
  55     FT_ULong len;
  56     FT_Byte* buf;
  57
  58     FT_ULong buf_len;
  59     FT_ULong j;
  60
  61
  62     *table_info = MISSING;
  63
  64     error = FT_Sfnt_Table_Info(sfnt->face, (FT_UInt)i, &tag, &len);
  65     if (error)
  66     {
  67       if (error == FT_Err_Table_Missing)
  68         continue;
  69       else
  70         return error;
  71     }
  72
  73     /* ignore zero-length tables */
  74     else if (!len)
  75       continue;
  76
  77     /* ignore tables which we are going to create by ourselves, */
  78     /* or which would become invalid otherwise */
  79     else if (tag == TTAG_cvt
  80              || tag == TTAG_fpgm
  81              || tag == TTAG_gasp
  82              || tag == TTAG_hdmx
  83              || tag == TTAG_LTSH
  84              || tag == TTAG_prep
  85              || tag == TTAG_TTFA
  86              || tag == TTAG_VDMX)
  87       continue;
  88
  89     else if (tag == TTAG_DSIG)
  90     {
  91       font->have_DSIG = 1;
  92       continue;
  93     }
  94
  95     /* make the allocated buffer length a multiple of 4 */
  96     buf_len = (len + 3) & ~3U;
  97     buf = (FT_Byte*)malloc(buf_len);
  98     if (!buf)
  99       return FT_Err_Out_Of_Memory;
 100
 101     /* pad end of buffer with zeros */
 102     buf[buf_len - 1] = 0x00;
 103     buf[buf_len - 2] = 0x00;
 104     buf[buf_len - 3] = 0x00;
 105
 106     /* load table */
 107     error = FT_Load_Sfnt_Table(sfnt->face, tag, 0, buf, &len);
 108     if (error)
 109       goto Err;
 110
 111     /* check whether we already have this table */
 112     for (j = 0; j < font->num_tables; j++)
 113     {
 114       SFNT_Table* table = &font->tables[j];
 115
 116
 117       if (table->tag == tag
 118           && table->len == len
 119           && !memcmp(table->buf, buf, len))
 120         break;
 121     }
 122
 123     if (tag == TTAG_head)
 124       sfnt->head_idx = j;
 125     else if (tag == TTAG_glyf)
 126       sfnt->glyf_idx = j;
 127     else if (tag == TTAG_hmtx)
 128       sfnt->hmtx_idx = j;
 129     else if (tag == TTAG_loca)
 130       sfnt->loca_idx = j;
 131     else if (tag == TTAG_maxp)
 132     {
 133       sfnt->maxp_idx = j;
 134
 135       sfnt->max_components = (FT_UShort)(buf[MAXP_MAX_COMPONENTS_OFFSET] << 8
 136                                          | buf[MAXP_MAX_COMPONENTS_OFFSET + 1]);
 137     }
 138     else if (tag == TTAG_name)
 139       sfnt->name_idx = j;
 140     else if (tag == TTAG_post)
 141       sfnt->post_idx = j;
 142     else if (tag == TTAG_OS2)
 143       sfnt->OS2_idx = j;
 144     else if (tag == TTAG_GPOS)
 145       sfnt->GPOS_idx = j;
 146
 147     if (j == font->num_tables)
 148     {
 149       /* add element to table array if it is missing or different; */
 150       /* in case of success, `buf' gets linked and is eventually */
 151       /* freed in `TA_font_unload' */
 152       error = TA_font_add_table(font, table_info, tag, len, buf);
 153       if (error)
 154         goto Err;
 155     }
 156     else
 157     {
 158       /* reuse existing SFNT table */
 159       free(buf);
 160       *table_info = j;
 161     }
 162     continue;
 163
 164   Err:
 165     free(buf);
 166     return error;
 167   }
 168
 169   /* no (non-empty) `glyf', `loca', `head', or `maxp' table; */
 170   /* this can't be a valid TTF with outlines */
 171   if (sfnt->glyf_idx == MISSING
 172       || sfnt->loca_idx == MISSING
 173       || sfnt->head_idx == MISSING
 174       || sfnt->maxp_idx == MISSING)
 175     return TA_Err_Invalid_Font_Type;
 176
 177   return TA_Err_Ok;
 178 }
 179
 180 /* end of tasfnt.c */