sfntly/font_factory.h

/*
 * Copyright 2011 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef TYPOGRAPHY_FONT_SFNTLY_SRC_SFNTLY_FONT_FACTORY_H_
#define TYPOGRAPHY_FONT_SFNTLY_SRC_SFNTLY_FONT_FACTORY_H_

#include <vector>

#include "sfntly/port/refcount.h"
#include "sfntly/port/type.h"
#include "sfntly/font.h"

namespace sfntly {

class FontFactory : public RefCounted<FontFactory> {
 private:
  // Offsets to specific elements in the underlying data. These offsets are
  // relative to the start of the table or the start of sub-blocks within the
  // table.
  struct Offset {
    // Offsets within the main directory
    static const int32_t kTTCTag;
    static const int32_t kVersion;
    static const int32_t kNumFonts;
    static const int32_t kOffsetTable;

    // TTC Version 2.0 extensions
    // offsets from end of OffsetTable
    static const int32_t kulDsigTag;
    static const int32_t kulDsigLength;
    static const int32_t kulDsigOffset;
  };

  FontFactory();

 public:  // class is final, no virtual functions unless from parent
  virtual ~FontFactory();

  // Factory method for the construction of a font factory.
  static CALLER_ATTACH FontFactory* getInstance();

  // Toggle whether fonts that are loaded are fingerprinted with a SHA-1 hash.
  // If a font is fingerprinted then a SHA-1 hash is generated at load time and
  // stored in the font. This is useful for uniquely identifying fonts. By
  // default this is turned on.
  // @param fingerprint whether fingerprinting should be turned on or off
  // TODO(arthurhsu): IMPLEMENT: C++ port currently don't do any SHA-1
  void fingerprintFont(bool fingerprint);
  bool fingerprintFont();

  // Load the font(s) from the input stream. The current settings on the factory
  // are used during the loading process. One or more fonts are returned if the
  // stream contains valid font data. Some font container formats may have more
  // than one font and in this case multiple font objects will be returned. If
  // the data in the stream cannot be parsed or is invalid an array of size zero
  // will be returned.
  void loadFonts(InputStream* is, FontArray* output);

  // Load the font(s) from the input stream into font builders. The current
  // settings on the factory are used during the loading process. One or more
  // font builders are returned if the stream contains valid font data. Some
  // font container formats may have more than one font and in this case
  // multiple font builder objects will be returned. If the data in the stream
  // cannot be parsed or is invalid an array of size zero will be returned.
  void loadFontsForBuilding(InputStream* is, FontBuilderArray* output);

 private:
  Font* loadSingleOTF(InputStream* is);
  void loadCollection(InputStream* is, FontArray* output);
  Font::Builder* loadSingleOTFForBuilding(InputStream* is);
  void loadCollectionForBuilding(InputStream* is, FontBuilderArray* builders);
  static bool isCollection(PushbackInputStream* pbis);

 public:
  // ByteArray font loading
  // Load the font(s) from the byte array. The current settings on the factory
  // are used during the loading process. One or more fonts are returned if the
  // stream contains valid font data. Some font container formats may have more
  // than one font and in this case multiple font objects will be returned. If
  // the data in the stream cannot be parsed or is invalid an array of size zero
  // will be returned.
  void loadFonts(ByteArray* ba, FontArray* output);

  // Load the font(s) from the byte array into font builders. The current
  // settings on the factory are used during the loading process. One or more
  // font builders are returned if the stream contains valid font data. Some
  // font container formats may have more than one font and in this case
  // multiple font builder objects will be returned. If the data in the stream
  // cannot be parsed or is invalid an array of size zero will be returned.
  void loadFontsForBuilding(ByteArray* ba, FontBuilderArray* output);

 private:
  CALLER_ATTACH Font* loadSingleOTF(ByteArray* ba);
  void loadCollection(ByteArray* ba, FontArray* output);
  CALLER_ATTACH Font::Builder*
      loadSingleOTFForBuilding(ByteArray* ba, int32_t offset_to_offset_table);
  void loadCollectionForBuilding(ByteArray* ba, FontBuilderArray* builders);
  static bool isCollection(ByteArray* ba);

 public:
  CALLER_ATTACH WritableFontData* getNewData(int32_t capacity);
  CALLER_ATTACH WritableFontData* getNewFixedData(int32_t capacity);
  CALLER_ATTACH WritableFontData* getNewGrowableData(int32_t capacity);
  CALLER_ATTACH WritableFontData*
      getNewGrowableData(ReadableFontData* src_data);
  CALLER_ATTACH ByteArray* getNewArray(int32_t length);
  CALLER_ATTACH ByteArray* getNewGrowableArray(int32_t length);

 public:
  // Font serialization
  // Serialize the font to the output stream.
  // NOTE: in this port we attempted not to implement I/O stream because dealing
  //       with cross-platform I/O stream itself is big enough as a project.
  //       Byte buffer it is.
  void serializeFont(Font* font, OutputStream* os);

  // Set the table ordering to be used in serializing a font. The table ordering
  // is an ordered list of table ids and tables will be serialized in the order
  // given. Any tables whose id is not listed in the ordering will be placed in
  // an unspecified order following those listed.
  void setSerializationTableOrdering(const IntegerList& table_ordering);

  // Get an empty font builder for creating a new font from scratch.
  CALLER_ATTACH Font::Builder* newFontBuilder();

 private:
  bool fingerprint_;
  IntegerList table_ordering_;
};
typedef Ptr<FontFactory> FontFactoryPtr;

}  // namespace sfntly

#endif  // TYPOGRAPHY_FONT_SFNTLY_SRC_SFNTLY_FONT_FACTORY_H_