HasselbladDecompressor.cpp

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/*
    RawSpeed - RAW file decoder.
 
    Copyright (C) 2009-2014 Klaus Post
    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
*/
 
#include "decompressors/HasselbladDecompressor.h"
#include "adt/Array1DRef.h"
#include "adt/Array2DRef.h"
#include "adt/Invariant.h"
#include "adt/Point.h"
#include "bitstreams/BitStreamerMSB32.h"
#include "codes/PrefixCodeDecoder.h"
#include "common/RawImage.h"
#include "decoders/RawDecoderException.h"
#include "io/ByteStream.h"
#include <cstdint>
#include <utility>
 
namespace rawspeed {
 
HasselbladDecompressor::HasselbladDecompressor(RawImage mRaw_,
                                               const PerComponentRecipe& rec_,
                                               Array1DRef<const uint8_t> input_)
    : mRaw(std::move(mRaw_)), rec(rec_), input(input_) {
  if (mRaw->getDataType() != RawImageType::UINT16)
    ThrowRDE("Unexpected data type");
 
  if (mRaw->getCpp() != 1 || mRaw->getBpp() != sizeof(uint16_t))
    ThrowRDE("Unexpected cpp: %u", mRaw->getCpp());
 
  // FIXME: could be wrong. max "active pixels" - "100 MP"
  if (!mRaw->dim.hasPositiveArea() || mRaw->dim.x % 2 != 0 ||
      mRaw->dim.x > 12000 || mRaw->dim.y > 8842) {
    ThrowRDE("Unexpected image dimensions found: (%d; %d)", mRaw->dim.x,
             mRaw->dim.y);
  }
 
  if (rec.ht.isFullDecode())
    ThrowRDE("Huffman table is of a full decoding variety");
}
 
// Returns len bits as a signed value.
// Highest bit is a sign bit
inline int HasselbladDecompressor::getBits(BitStreamerMSB32& bs, int len) {
  if (!len)
    return 0;
  int diff = bs.getBits(len);
  diff = PrefixCodeDecoder<>::extend(diff, len);
  if (diff == 65535)
    return -32768;
  return diff;
}
 
ByteStream::size_type HasselbladDecompressor::decompress() {
  const Array2DRef<uint16_t> out(mRaw->getU16DataAsUncroppedArray2DRef());
 
  invariant(out.height() > 0);
  invariant(out.width() > 0);
  invariant(out.width() % 2 == 0);
 
  const auto ht = rec.ht;
  ht.verifyCodeValuesAsDiffLengths();
 
  BitStreamerMSB32 bitStreamer(input);
  // Pixels are packed two at a time, not like LJPEG:
  // [p1_length_as_huffman][p2_length_as_huffman][p0_diff_with_length][p1_diff_with_length]|NEXT
  // PIXELS
  for (int row = 0; row < out.height(); row++) {
    int p1 = rec.initPred;
    int p2 = rec.initPred;
    for (int col = 0; col < out.width(); col += 2) {
      int len1 = ht.decodeCodeValue(bitStreamer);
      int len2 = ht.decodeCodeValue(bitStreamer);
      p1 += getBits(bitStreamer, len1);
      p2 += getBits(bitStreamer, len2);
      // NOTE: this is rather unusual and weird, but appears to be correct.
      // clampBits(p, 16) results in completely garbled images.
      out(row, col) = uint16_t(p1);
      out(row, col + 1) = uint16_t(p2);
    }
  }
  return bitStreamer.getStreamPosition();
}
 
} // namespace rawspeed