// Copyright 2016 The PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <cstdint>

#include "core/fpdfapi/parser/cpdf_stream.h"
#include "core/fpdfapi/parser/cpdf_stream_acc.h"
#include "core/fxcodec/JBig2_DocumentContext.h"
#include "core/fxcodec/codec/ccodec_jbig2module.h"
#include "core/fxcodec/jbig2/JBig2_Context.h"
#include "core/fxcrt/fx_safe_types.h"
#include "core/fxge/dib/cfx_dibitmap.h"
#include "core/fxge/fx_dib.h"
#include "third_party/base/ptr_util.h"

static uint32_t GetInteger(const uint8_t* data) {
  return data[0] | data[1] << 8 | data[2] << 16 | data[3] << 24;
}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
  const size_t kParameterSize = 8;
  if (size < kParameterSize)
    return 0;

  uint32_t width = GetInteger(data);
  uint32_t height = GetInteger(data + 4);
  size -= kParameterSize;
  data += kParameterSize;

  static constexpr uint32_t kMemLimit = 1024 * 1024 * 1024;  // 1 GB.
  static constexpr uint32_t k1bppRgbComponents = 4;  // From CFX_DIBitmap impl.
  FX_SAFE_UINT32 mem = width;
  mem *= height;
  mem *= k1bppRgbComponents;
  if (!mem.IsValid() || mem.ValueOrDie() > kMemLimit)
    return 0;

  auto bitmap = pdfium::MakeRetain<CFX_DIBitmap>();
  if (!bitmap->Create(width, height, FXDIB_1bppRgb))
    return 0;

  auto stream = pdfium::MakeUnique<CPDF_Stream>();
  stream->AsStream()->SetData(data, size);

  auto src_stream = pdfium::MakeRetain<CPDF_StreamAcc>(stream->AsStream());
  src_stream->LoadAllData(true);

  CCodec_Jbig2Module module;
  CCodec_Jbig2Context jbig2_context;
  std::unique_ptr<JBig2_DocumentContext> document_context;
  FXCODEC_STATUS status = module.StartDecode(
      &jbig2_context, &document_context, width, height, src_stream, nullptr,
      bitmap->GetBuffer(), bitmap->GetPitch(), nullptr);

  while (status == FXCODEC_STATUS_DECODE_TOBECONTINUE)
    status = module.ContinueDecode(&jbig2_context, nullptr);
  return 0;
}