src/taloca.c

   1 /* taloca.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_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   if (offset > 0xFFFF * 2)
  55     loca_format = 1;
  56   else
  57     loca_format = 0;
  58
  59   /* fill table */
  60   if (loca_format)
  61   {
  62     loca_table->len = (data->num_glyphs + 1) * 4;
  63     buf_new = (FT_Byte*)realloc(loca_table->buf, loca_table->len);
  64     if (!buf_new)
  65       return FT_Err_Out_Of_Memory;
  66     else
  67       loca_table->buf = buf_new;
  68
  69     p = loca_table->buf;
  70     offset = 0;
  71     glyph = data->glyphs;
  72
  73     for (i = 0; i < data->num_glyphs; i++, glyph++)
  74     {
  75       offset = (offset + 3) & ~3;
  76
  77       *(p++) = BYTE1(offset);
  78       *(p++) = BYTE2(offset);
  79       *(p++) = BYTE3(offset);
  80       *(p++) = BYTE4(offset);
  81
  82       offset += glyph->len1 + glyph->len2 + glyph->ins_len;
  83       if (glyph->len2 || glyph->ins_len)
  84         offset += 2;
  85     }
  86
  87     /* last element holds the size of the `glyf' table */
  88     *(p++) = BYTE1(offset);
  89     *(p++) = BYTE2(offset);
  90     *(p++) = BYTE3(offset);
  91     *(p++) = BYTE4(offset);
  92   }
  93   else
  94   {
  95     loca_table->len = (data->num_glyphs + 1) * 2;
  96     buf_new = (FT_Byte*)realloc(loca_table->buf,
  97                                 (loca_table->len + 3) & ~3);
  98     if (!buf_new)
  99       return FT_Err_Out_Of_Memory;
 100     else
 101       loca_table->buf = buf_new;
 102
 103     p = loca_table->buf;
 104     offset = 0;
 105     glyph = data->glyphs;
 106
 107     for (i = 0; i < data->num_glyphs; i++, glyph++)
 108     {
 109       offset = (offset + 1) & ~1;
 110
 111       *(p++) = HIGH(offset);
 112       *(p++) = LOW(offset);
 113
 114       offset += (glyph->len1 + glyph->len2 + glyph->ins_len + 1) >> 1;
 115       if (glyph->len2 || glyph->ins_len)
 116         offset += 1;
 117     }
 118
 119     /* last element holds the size of the `glyf' table */
 120     *(p++) = HIGH(offset);
 121     *(p++) = LOW(offset);
 122
 123     /* pad `loca' table to make its length a multiple of 4 */
 124     if (loca_table->len % 4 == 2)
 125     {
 126       *(p++) = 0;
 127       *(p++) = 0;
 128     }
 129   }
 130
 131   loca_table->checksum = TA_table_compute_checksum(loca_table->buf,
 132                                                    loca_table->len);
 133   loca_table->processed = 1;
 134
 135   head_table->buf[LOCA_FORMAT_OFFSET] = loca_format;
 136
 137   return TA_Err_Ok;
 138 }
 139
 140 /* end of taloca.c */