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

#include <stdint.h>

#include "core/fxcodec/jbig2/jbig2_context.h"
#include "core/fxcodec/jbig2/jbig2_decoder.h"
#include "core/fxcodec/jbig2/jbig2_document_context.h"
#include "core/fxcrt/compiler_specific.h"
#include "core/fxcrt/fx_safe_types.h"
#include "core/fxcrt/span.h"
#include "core/fxge/dib/cfx_dibitmap.h"
#include "core/fxge/dib/fx_dib.h"
#include "testing/fuzzers/pdfium_fuzzer_util.h"

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

  // SAFETY: trusted arguments from fuzzer.
  auto span = UNSAFE_BUFFERS(pdfium::span(data, size));
  uint32_t width = GetInteger(data);
  uint32_t height = GetInteger(UNSAFE_TODO(data + 4));
  span = span.subspan(kParameterSize);

  static constexpr uint32_t kMemLimit = 512000000;   // 512 MB
  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_Format::k1bppRgb)) {
    return 0;
  }

  JBig2_DocumentContext document_context;
  Jbig2Context jbig2_context;

  const bool reject_large_regions_when_fuzzing = true;
  FXCODEC_STATUS status = Jbig2Decoder::StartDecode(
      &jbig2_context, &document_context, width, height, span, 1, {}, 0,
      bitmap->GetWritableBuffer(), bitmap->GetPitch(), nullptr,
      reject_large_regions_when_fuzzing);

  while (status == FXCODEC_STATUS::kDecodeToBeContinued) {
    status = Jbig2Decoder::ContinueDecode(&jbig2_context, nullptr);
  }
  return 0;
}