DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (8e1e5dbe95dc)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176
// Copyright (c) 2009-2017 The OTS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "post.h"

#include "maxp.h"

// post - PostScript
// http://www.microsoft.com/typography/otspec/post.htm

namespace ots {

bool OpenTypePOST::Parse(const uint8_t *data, size_t length) {
  Buffer table(data, length);

  if (!table.ReadU32(&this->version)) {
    return Error("Failed to read table version");
  }

  if (this->version != 0x00010000 &&
      this->version != 0x00020000 &&
      this->version != 0x00030000) {
    // 0x00025000 is deprecated. We don't accept it.
    return Error("Unsupported table version 0x%x", this->version);
  }

  if (!table.ReadU32(&this->italic_angle) ||
      !table.ReadS16(&this->underline) ||
      !table.ReadS16(&this->underline_thickness) ||
      !table.ReadU32(&this->is_fixed_pitch) ||
      // We don't care about the memory usage fields. We'll set all these to
      // zero when serialising
      !table.Skip(16)) {
    return Error("Failed to read table header");
  }

  if (this->underline_thickness < 0) {
    this->underline_thickness = 1;
  }

  if (this->version == 0x00010000 || this->version == 0x00030000) {
    return true;
  }

  // We have a version 2 table with a list of Pascal strings at the end

  uint16_t num_glyphs = 0;
  if (!table.ReadU16(&num_glyphs)) {
    return Error("Failed to read numberOfGlyphs");
  }

  OpenTypeMAXP* maxp = static_cast<OpenTypeMAXP*>
    (GetFont()->GetTable(OTS_TAG_MAXP));
  if (!maxp) {
    return Error("Missing required maxp table");
  }

  if (num_glyphs == 0) {
    if (maxp->num_glyphs > 258) {
      return Error("Can't have no glyphs in the post table if there are more "
                   "than 258 glyphs in the font");
    }
    // workaround for fonts in http://www.fontsquirrel.com/fontface
    // (e.g., yataghan.ttf).
    this->version = 0x00010000;
    return Warning("Table version is 1, but no glyph names are found");
  }

  if (num_glyphs != maxp->num_glyphs) {
    // Note: Fixedsys500c.ttf seems to have inconsistent num_glyphs values.
    return Error("Bad number of glyphs: %d", num_glyphs);
  }

  this->glyph_name_index.resize(num_glyphs);
  for (unsigned i = 0; i < num_glyphs; ++i) {
    if (!table.ReadU16(&this->glyph_name_index[i])) {
      return Error("Failed to read glyph name %d", i);
    }
    // Note: A strict interpretation of the specification requires name indexes
    // are less than 32768. This, however, excludes fonts like unifont.ttf
    // which cover all of unicode.
  }

  // Now we have an array of Pascal strings. We have to check that they are all
  // valid and read them in.
  const size_t strings_offset = table.offset();
  const uint8_t *strings = data + strings_offset;
  const uint8_t *strings_end = data + length;

  for (;;) {
    if (strings == strings_end) break;
    const unsigned string_length = *strings;
    if (strings + 1 + string_length > strings_end) {
      return Error("Bad string length %d", string_length);
    }
    if (std::memchr(strings + 1, '\0', string_length)) {
      return Error("Bad string of length %d", string_length);
    }
    this->names.push_back(
        std::string(reinterpret_cast<const char*>(strings + 1), string_length));
    strings += 1 + string_length;
  }
  const unsigned num_strings = this->names.size();

  // check that all the references are within bounds
  for (unsigned i = 0; i < num_glyphs; ++i) {
    unsigned offset = this->glyph_name_index[i];
    if (offset < 258) {
      continue;
    }

    offset -= 258;
    if (offset >= num_strings) {
      return Error("Bad string index %d", offset);
    }
  }

  return true;
}

bool OpenTypePOST::Serialize(OTSStream *out) {
  // OpenType with CFF glyphs must have v3 post table.
  if (GetFont()->GetTable(OTS_TAG_CFF) && this->version != 0x00030000) {
    return Error("Only version supported for fonts with CFF table is 0x00030000"
                 " not 0x%x", this->version);
  }

  if (!out->WriteU32(this->version) ||
      !out->WriteU32(this->italic_angle) ||
      !out->WriteS16(this->underline) ||
      !out->WriteS16(this->underline_thickness) ||
      !out->WriteU32(this->is_fixed_pitch) ||
      !out->WriteU32(0) ||
      !out->WriteU32(0) ||
      !out->WriteU32(0) ||
      !out->WriteU32(0)) {
    return Error("Failed to write post header");
  }

  if (this->version != 0x00020000) {
    return true;  // v1.0 and v3.0 does not have glyph names.
  }

  const uint16_t num_indexes =
      static_cast<uint16_t>(this->glyph_name_index.size());
  if (num_indexes != this->glyph_name_index.size() ||
      !out->WriteU16(num_indexes)) {
    return Error("Failed to write number of indices");
  }

  for (uint16_t i = 0; i < num_indexes; ++i) {
    if (!out->WriteU16(this->glyph_name_index[i])) {
      return Error("Failed to write name index %d", i);
    }
  }

  // Now we just have to write out the strings in the correct order
  for (unsigned i = 0; i < this->names.size(); ++i) {
    const std::string& s = this->names[i];
    const uint8_t string_length = static_cast<uint8_t>(s.size());
    if (string_length != s.size() ||
        !out->Write(&string_length, 1)) {
      return Error("Failed to write string %d", i);
    }
    // Some ttf fonts (e.g., frank.ttf on Windows Vista) have zero-length name.
    // We allow them.
    if (string_length > 0 && !out->Write(s.data(), string_length)) {
      return Error("Failed to write string length for string %d", i);
    }
  }

  return true;
}

}  // namespace ots