LJpegDecompressor.h

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/*
    RawSpeed - RAW file decoder.
 
    Copyright (C) 2017 Axel Waggershauser
    Copyright (C) 2023 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/Array1DRef.h"
#include "adt/Array2DRef.h"
#include "adt/Point.h"
#include "bitstreams/BitStreamerJPEG.h"
#include "codes/PrefixCodeDecoder.h"
#include "common/RawImage.h"
#include "io/ByteStream.h"
#include <array>
#include <cstddef>
#include <cstdint>
#include <functional>
#include <utility>
#include <vector>
 
namespace rawspeed {
 
// Decompresses Lossless JPEGs, with 2-4 components
 
class LJpegDecompressor final {
public:
  struct Frame final {
    const iPoint2D mcu;
    const iPoint2D dim;
  };
  struct PerComponentRecipe final {
    const PrefixCodeDecoder<>& ht;
    const uint16_t initPred;
  };
 
private:
  RawImage mRaw;
  const Array1DRef<const uint8_t> input;
 
  const iRectangle2D imgFrame;
 
  const Frame frame;
  const std::vector<PerComponentRecipe> rec;
  const int numLJpegRowsPerRestartInterval;
 
  int numFullMCUs = 0;
  int trailingPixels = 0;
 
  template <int N_COMP, size_t... I>
  [[nodiscard]] std::array<std::reference_wrapper<const PrefixCodeDecoder<>>,
                           N_COMP>
      getPrefixCodeDecodersImpl(std::index_sequence<I...> /*unused*/) const;
 
  template <int N_COMP>
  [[nodiscard]] std::array<std::reference_wrapper<const PrefixCodeDecoder<>>,
                           N_COMP>
  getPrefixCodeDecoders() const;
 
  template <int N_COMP>
  [[nodiscard]] std::array<uint16_t, N_COMP> getInitialPreds() const;
 
  template <const iPoint2D& MCUSize, int N_COMP>
  __attribute__((always_inline)) inline void decodeRowN(
      Array2DRef<uint16_t> outStripe, Array2DRef<const uint16_t> pred,
      std::array<std::reference_wrapper<const PrefixCodeDecoder<>>, N_COMP> ht,
      BitStreamerJPEG& bs) const;
 
  template <const iPoint2D& MCUSize>
  [[nodiscard]] __attribute__((noinline)) ByteStream::size_type decodeN() const;
 
public:
  LJpegDecompressor(RawImage img, iRectangle2D imgFrame, Frame frame,
                    std::vector<PerComponentRecipe> rec,
                    int numLJpegRowsPerRestartInterval_,
                    Array1DRef<const uint8_t> input);
 
  [[nodiscard]] ByteStream::size_type decode() const;
};
 
} // namespace rawspeed