third_party/woff2/src/font.h

   1 // Copyright 2013 Google Inc. All Rights Reserved.
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 // http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14 //
  15 // Data model for a font file in sfnt format, reading and writing functions and
  16 // accessors for the glyph data.
  17
  18 #ifndef WOFF2_FONT_H_
  19 #define WOFF2_FONT_H_
  20
  21 #include <stddef.h>
  22 #include <inttypes.h>
  23 #include <map>
  24 #include <vector>
  25
  26 namespace woff2 {
  27
  28 // Represents an sfnt font file. Only the table directory is parsed, for the
  29 // table data we only store a raw pointer, therefore a font object is valid only
  30 // as long the data from which it was parsed is around.
  31 struct Font {
  32   uint32_t flavor;
  33   uint16_t num_tables;
  34
  35   struct Table {
  36     uint32_t tag;
  37     uint32_t checksum;
  38     uint32_t offset;
  39     uint32_t length;
  40     const uint8_t* data;
  41
  42     // Buffer used to mutate the data before writing out.
  43     std::vector<uint8_t> buffer;
  44   };
  45   std::map<uint32_t, Table> tables;
  46
  47   Table* FindTable(uint32_t tag);
  48   const Table* FindTable(uint32_t tag) const;
  49 };
  50
  51 // Parses the font from the given data. Returns false on parsing failure or
  52 // buffer overflow. The font is valid only so long the input data pointer is
  53 // valid.
  54 bool ReadFont(const uint8_t* data, size_t len, Font* font);
  55
  56 // Returns the file size of the font.
  57 size_t FontFileSize(const Font& font);
  58
  59 // Writes the font into the specified dst buffer. The dst_size should be the
  60 // same as returned by FontFileSize(). Returns false upon buffer overflow (which
  61 // should not happen if dst_size was computed by FontFileSize()).
  62 bool WriteFont(const Font& font, uint8_t* dst, size_t dst_size);
  63
  64 // Returns the number of glyphs in the font.
  65 // NOTE: Currently this works only for TrueType-flavored fonts, will return
  66 // zero for CFF-flavored fonts.
  67 int NumGlyphs(const Font& font);
  68
  69 // Returns the index format of the font
  70 int IndexFormat(const Font& font);
  71
  72 // Sets *glyph_data and *glyph_size to point to the location of the glyph data
  73 // with the given index. Returns false if the glyph is not found.
  74 bool GetGlyphData(const Font& font, int glyph_index,
  75                   const uint8_t** glyph_data, size_t* glyph_size);
  76
  77 // Removes the digital signature (DSIG) table
  78 bool RemoveDigitalSignature(Font* font);
  79
  80 } // namespace woff2
  81
  82 #endif  // WOFF2_FONT_H_