agl / otc

OpenType Condom

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Add README.
Adam Langley (author)
Thu Apr 09 14:55:48 -0700 2009
commit  9cf338554f3b7a1a018f25b3dec0b5148af17554
tree    bd8844355f4e36935c142676109049fcd00d71fe
parent  0f56762acc72b638858261c005f03ba5ef40f2b8
otc / src / head.cc
100644 117 lines (93 sloc) 2.816 kb
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#include "otc.h"
#include "head.h"
 
bool
otc_head_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
  Buffer table(data, length);
  file->head = new OpenTypeHEAD;
 
  // http://www.microsoft.com/typography/otspec/head.htm
 
  uint32_t version;
  if (!table.ReadU32(&version) ||
      !table.ReadU32(&file->head->revision)) {
    return failure();
  }
 
  if (version >> 16 != 1)
    return failure();
 
  // Skip the checksum adjustment
  table.Skip(4);
 
  uint32_t magic;
  if (!table.ReadTag(&magic) ||
      memcmp(&magic, "\x5F\x0F\x3C\xF5", 4)) {
    return failure();
  }
 
  if (!table.ReadU16(&file->head->flags))
    return failure();
 
  // We allow bits 0..4, 11..13
  file->head->flags &= 0x381f;
 
  if (!table.ReadU16(&file->head->ppem))
    return failure();
 
  // ppem must be in range and a power of two
  if (file->head->ppem < 16 ||
      file->head->ppem > 16384 ||
      ((file->head->ppem - 1) & file->head->ppem)) {
    return failure();
  }
 
  if (!table.ReadR64(&file->head->created) ||
      !table.ReadR64(&file->head->modified)) {
    return failure();
  }
 
  if (!table.ReadS16(&file->head->xmin) ||
      !table.ReadS16(&file->head->ymin) ||
      !table.ReadS16(&file->head->xmax) ||
      !table.ReadS16(&file->head->ymax)) {
    return failure();
  }
 
  if (!table.ReadU16(&file->head->mac_style))
    return failure();
 
  // We allow bits 0..6
  file->head->mac_style &= 0x3f;
 
  if (!table.ReadU16(&file->head->min_ppem))
    return failure();
 
  // We don't care about the font direction hint
  table.Skip(2);
 
  if (!table.ReadS16(&file->head->index_to_loc_format))
    return failure();
  if (file->head->index_to_loc_format > 1)
    return failure();
 
  int16_t glyph_data_format;
  if (!table.ReadS16(&glyph_data_format) ||
      glyph_data_format) {
    return failure();
  }
 
  return true;
}
 
bool
otc_head_should_serialise(OpenTypeFile *file) {
  return file->head;
}
 
bool
otc_head_serialise(OTCStream *out, OpenTypeFile *file) {
  if (!out->WriteU32(0x00010000) ||
      !out->WriteU32(file->head->revision) ||
      !out->WriteU32(0) ||  // check sum not filled in yet
      !out->WriteU32(0x5F0F3CF5) ||
      !out->WriteU16(file->head->flags) ||
      !out->WriteU16(file->head->ppem) ||
      !out->WriteR64(file->head->created) ||
      !out->WriteR64(file->head->modified) ||
      !out->WriteS16(file->head->xmin) ||
      !out->WriteS16(file->head->ymin) ||
      !out->WriteS16(file->head->xmax) ||
      !out->WriteS16(file->head->ymax) ||
      !out->WriteU16(file->head->mac_style) ||
      !out->WriteU16(file->head->min_ppem) ||
      !out->WriteS16(2) ||
      !out->WriteS16(file->head->index_to_loc_format) ||
      !out->WriteS16(0)) {
    return failure();
  }
 
  return true;
}
 
void
otc_head_free(OpenTypeFile *file) {
  delete file->head;
}