lib/taloca.c

   1 /* taloca.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 FT_Error
  20 TA_sfnt_build_loca_table(SFNT* sfnt,
  21                          FONT* font)
  22 {
  23   SFNT_Table* loca_table = &font->tables[sfnt->loca_idx];
  24   SFNT_Table* glyf_table = &font->tables[sfnt->glyf_idx];
  25   SFNT_Table* head_table = &font->tables[sfnt->head_idx];
  26
  27   glyf_Data* data = (glyf_Data*)glyf_table->data;
  28   GLYPH* glyph;
  29
  30   FT_ULong offset;
  31   FT_Byte loca_format;
  32   FT_Byte* buf_new;
  33   FT_Byte* p;
  34   FT_UShort i;
  35
  36
  37   if (loca_table->processed)
  38     return TA_Err_Ok;
  39
  40   /* get largest offset */
  41   offset = 0;
  42   glyph = data->glyphs;
  43
  44   for (i = 0; i < data->num_glyphs; i++, glyph++)
  45   {
  46     /* glyph records should have offsets which are multiples of 4 */
  47     offset = (offset + 3) & ~3;
  48     offset += glyph->len1 + glyph->len2 + glyph->ins_len;
  49     /* add two bytes for the instructionLength field */
  50     if (glyph->len2 || glyph->ins_len)
  51       offset += 2;
  52   }
  53
  54   /* to make the short format of the `loca' table always work, */
  55   /* the `glyf' table's length is adjusted to an even value */
  56   offset = (offset + 1) & ~1;
  57
  58   if (offset > 0xFFFF * 2)
  59     loca_format = 1;
  60   else
  61     loca_format = 0;
  62
  63   /* fill table */
  64   if (loca_format)
  65   {
  66     loca_table->len = (data->num_glyphs + 1) * 4;
  67     buf_new = (FT_Byte*)realloc(loca_table->buf, loca_table->len);
  68     if (!buf_new)
  69       return FT_Err_Out_Of_Memory;
  70     else
  71       loca_table->buf = buf_new;
  72
  73     p = loca_table->buf;
  74     offset = 0;
  75     glyph = data->glyphs;
  76
  77     for (i = 0; i < data->num_glyphs; i++, glyph++)
  78     {
  79       offset = (offset + 3) & ~3;
  80
  81       *(p++) = BYTE1(offset);
  82       *(p++) = BYTE2(offset);
  83       *(p++) = BYTE3(offset);
  84       *(p++) = BYTE4(offset);
  85
  86       offset += glyph->len1 + glyph->len2 + glyph->ins_len;
  87       if (glyph->len2 || glyph->ins_len)
  88         offset += 2;
  89     }
  90
  91     /* last element holds the size of the `glyf' table */
  92     offset = (offset + 1) & ~1;
  93     *(p++) = BYTE1(offset);
  94     *(p++) = BYTE2(offset);
  95     *(p++) = BYTE3(offset);
  96     *(p++) = BYTE4(offset);
  97   }
  98   else
  99   {
 100     loca_table->len = (data->num_glyphs + 1) * 2;
 101     buf_new = (FT_Byte*)realloc(loca_table->buf,
 102                                 (loca_table->len + 3) & ~3);
 103     if (!buf_new)
 104       return FT_Err_Out_Of_Memory;
 105     else
 106       loca_table->buf = buf_new;
 107
 108     p = loca_table->buf;
 109     offset = 0;
 110     glyph = data->glyphs;
 111
 112     for (i = 0; i < data->num_glyphs; i++, glyph++)
 113     {
 114       offset = (offset + 1) & ~1;
 115
 116       *(p++) = HIGH(offset);
 117       *(p++) = LOW(offset);
 118
 119       offset += (glyph->len1 + glyph->len2 + glyph->ins_len + 1) >> 1;
 120       if (glyph->len2 || glyph->ins_len)
 121         offset += 1;
 122     }
 123
 124     /* last element holds the size of the `glyf' table -- */
 125     /* this value must *not* be aligned to a multiple of 4 */
 126     *(p++) = HIGH(offset);
 127     *(p++) = LOW(offset);
 128
 129     /* pad `loca' table to make its length a multiple of 4 */
 130     if (loca_table->len % 4 == 2)
 131     {
 132       *(p++) = 0;
 133       *(p++) = 0;
 134     }
 135   }
 136
 137   loca_table->checksum = TA_table_compute_checksum(loca_table->buf,
 138                                                    loca_table->len);
 139   loca_table->processed = 1;
 140
 141   head_table->buf[LOCA_FORMAT_OFFSET] = loca_format;
 142
 143   return TA_Err_Ok;
 144 }
 145
 146 /* end of taloca.c */