lib/tatables.c

   1 /* tatables.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 <stdlib.h>
  17
  18 #include "ta.h"
  19
  20
  21 FT_Error
  22 TA_sfnt_add_table_info(SFNT* sfnt)
  23 {
  24   SFNT_Table_Info* table_infos_new;
  25
  26
  27   sfnt->num_table_infos++;
  28   table_infos_new =
  29     (SFNT_Table_Info*)realloc(sfnt->table_infos, sfnt->num_table_infos
  30                                                  * sizeof (SFNT_Table_Info));
  31   if (!table_infos_new)
  32   {
  33     sfnt->num_table_infos--;
  34     return FT_Err_Out_Of_Memory;
  35   }
  36   else
  37     sfnt->table_infos = table_infos_new;
  38
  39   sfnt->table_infos[sfnt->num_table_infos - 1] = MISSING;
  40
  41   return TA_Err_Ok;
  42 }
  43
  44
  45 FT_ULong
  46 TA_table_compute_checksum(FT_Byte* buf,
  47                           FT_ULong len)
  48 {
  49   FT_Byte* end_buf = buf + len;
  50   FT_ULong checksum = 0;
  51
  52
  53   /* we expect that the length of `buf' is a multiple of 4 */
  54
  55   while (buf < end_buf)
  56     checksum += NEXT_ULONG(buf);
  57
  58   return checksum;
  59 }
  60
  61
  62 FT_Error
  63 TA_font_add_table(FONT* font,
  64                   SFNT_Table_Info* table_info,
  65                   FT_ULong tag,
  66                   FT_ULong len,
  67                   FT_Byte* buf)
  68 {
  69   SFNT_Table* tables_new;
  70   SFNT_Table* table_last;
  71
  72
  73   font->num_tables++;
  74   tables_new = (SFNT_Table*)realloc(font->tables,
  75                                     font->num_tables * sizeof (SFNT_Table));
  76   if (!tables_new)
  77   {
  78     font->num_tables--;
  79     return FT_Err_Out_Of_Memory;
  80   }
  81   else
  82     font->tables = tables_new;
  83
  84   table_last = &font->tables[font->num_tables - 1];
  85
  86   table_last->tag = tag;
  87   table_last->len = len;
  88   table_last->buf = buf;
  89   table_last->checksum = TA_table_compute_checksum(buf, len);
  90   table_last->offset = 0; /* set in `TA_font_compute_table_offsets' */
  91   table_last->data = NULL;
  92   table_last->processed = 0;
  93
  94   /* link table and table info */
  95   *table_info = font->num_tables - 1;
  96
  97   return TA_Err_Ok;
  98 }
  99
 100
 101 void
 102 TA_sfnt_sort_table_info(SFNT* sfnt,
 103                         FONT* font)
 104 {
 105   /* Looking into an arbitrary TTF (with a `DSIG' table), tags */
 106   /* starting with an uppercase letter are sorted before lowercase */
 107   /* letters.  In other words, the alphabetical ordering (as */
 108   /* mandated by signing a font) is a simple numeric comparison of */
 109   /* the 32bit tag values. */
 110
 111   SFNT_Table* tables = font->tables;
 112
 113   SFNT_Table_Info* table_infos = sfnt->table_infos;
 114   FT_ULong num_table_infos = sfnt->num_table_infos;
 115
 116   FT_ULong i;
 117   FT_ULong j;
 118
 119
 120   /* bubble sort */
 121   for (i = 1; i < num_table_infos; i++)
 122   {
 123     for (j = i; j > 0; j--)
 124     {
 125       SFNT_Table_Info swap;
 126       FT_ULong tag1;
 127       FT_ULong tag2;
 128
 129
 130       tag1 = (table_infos[j] == MISSING)
 131                ? 0
 132                : tables[table_infos[j]].tag;
 133       tag2 = (table_infos[j - 1] == MISSING)
 134                ? 0
 135                : tables[table_infos[j - 1]].tag;
 136
 137       if (tag1 > tag2)
 138         break;
 139
 140       swap = table_infos[j];
 141       table_infos[j] = table_infos[j - 1];
 142       table_infos[j - 1] = swap;
 143     }
 144   }
 145 }
 146
 147
 148 void
 149 TA_font_compute_table_offsets(FONT* font,
 150                               FT_ULong start)
 151 {
 152   FT_ULong i;
 153   FT_ULong offset = start;
 154
 155
 156   for (i = 0; i < font->num_tables; i++)
 157   {
 158     SFNT_Table* table = &font->tables[i];
 159
 160
 161     table->offset = offset;
 162
 163     /* table offsets must be multiples of 4; */
 164     /* this also fits the actual buffer lengths */
 165     offset += (table->len + 3) & ~3U;
 166   }
 167 }
 168
 169 /* end of tatables.c */