lib/tahmtx.c

   1 /* tahmtx.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_update_hmtx_table(SFNT* sfnt,
  21                           FONT* font)
  22 {
  23   SFNT_Table* hmtx_table;
  24   FT_Byte* buf_new;
  25   FT_ULong buf_len;
  26   FT_ULong i;
  27
  28
  29   if (sfnt->hmtx_idx == MISSING)
  30     return TA_Err_Ok;
  31
  32   hmtx_table = &font->tables[sfnt->hmtx_idx];
  33
  34   if (hmtx_table->processed)
  35     return TA_Err_Ok;
  36
  37   /* the metrics of the added composite element doesn't matter; */
  38   /* for this reason, we simply append two zero bytes, */
  39   /* indicating a zero value in the `leftSideBearing' array */
  40   /* (this works because we don't increase the `numberOfHMetrics' field) */
  41
  42   hmtx_table->len += 2;
  43   /* make the allocated buffer length a multiple of 4 */
  44   buf_len = (hmtx_table->len + 3) & ~3U;
  45   buf_new = (FT_Byte*)realloc(hmtx_table->buf, buf_len);
  46   if (!buf_new)
  47   {
  48     hmtx_table->len -= 2;
  49     return FT_Err_Out_Of_Memory;
  50   }
  51
  52   /* pad end of buffer with zeros */
  53   for (i = hmtx_table->len - 2; i < buf_len; i++)
  54     buf_new[i] = 0x00;
  55
  56   hmtx_table->buf = buf_new;
  57   hmtx_table->checksum = TA_table_compute_checksum(hmtx_table->buf,
  58                                                    hmtx_table->len);
  59   hmtx_table->processed = 1;
  60
  61   return TA_Err_Ok;
  62 }
  63
  64 /* end of tahmtx.c */