DummyPrefixCodeDecoder.h

Go to the documentation of this file.

/*
    RawSpeed - RAW file decoder.
 
    Copyright (C) 2022 Roman Lebedev
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.
 
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
 
#pragma once
 
#include "adt/Invariant.h"
#include "bitstreams/BitStreamer.h"
#include "codes/AbstractPrefixCode.h"
#include "codes/HuffmanCode.h"
#include "codes/PrefixCode.h"
 
namespace rawspeed {
class Buffer;
 
template <typename CodeTag = BaselineCodeTag>
class DummyPrefixCodeDecoder final {
public:
  using Tag = CodeTag;
  using Traits = CodeTraits<CodeTag>;
 
  explicit DummyPrefixCodeDecoder(HuffmanCode<CodeTag> code) {}
  explicit DummyPrefixCodeDecoder(PrefixCode<CodeTag> code) {}
 
private:
  bool fullDecode = true;
  bool fixDNGBug16 = false;
 
public:
  void setup(bool fullDecode_, bool fixDNGBug16_) {
    fullDecode = fullDecode_;
    fixDNGBug16 = fixDNGBug16_;
  }
 
  [[nodiscard]] bool isFullDecode() const { return fullDecode; }
 
  template <typename BIT_STREAM>
  typename Traits::CodeValueTy decodeCodeValue(BIT_STREAM& bs) const {
    static_assert(
        BitStreamerTraits<BIT_STREAM>::canUseWithPrefixCodeDecoder,
        "This BitStreamer specialization is not marked as usable here");
    invariant(!fullDecode);
    return decode<BIT_STREAM, false>(bs);
  }
 
  template <typename BIT_STREAM> int decodeDifference(BIT_STREAM& bs) const {
    static_assert(
        BitStreamerTraits<BIT_STREAM>::canUseWithPrefixCodeDecoder,
        "This BitStreamer specialization is not marked as usable here");
    invariant(fullDecode);
    return decode<BIT_STREAM, true>(bs);
  }
 
  // The bool template paraeter is to enable two versions:
  // one returning only the length of the of diff bits (see Hasselblad),
  // one to return the fully decoded diff.
  // All ifs depending on this bool will be optimized out by the compiler
  template <typename BIT_STREAM, bool FULL_DECODE>
  int decode(BIT_STREAM& bs) const {
    static_assert(
        BitStreamerTraits<BIT_STREAM>::canUseWithPrefixCodeDecoder,
        "This BitStreamer specialization is not marked as usable here");
    invariant(FULL_DECODE == fullDecode);
 
    (void)bs;
 
    return 0; // The answer is always the same.
  }
};
 
} // namespace rawspeed