/*

 * Copyright 2018 Google, LLC

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#include "include/codec/SkCodec.h"

#include "include/core/SkBitmap.h"

#include "include/core/SkData.h"

bool FuzzIncrementalImageDecode(sk_sp<SkData> bytes) {

    auto codec = SkCodec::MakeFromData(bytes);

    if (!codec) {

        return false;

    }

    SkBitmap bm;

    if (!bm.tryAllocPixels(codec->getInfo())) {

        // May fail in memory-constrained fuzzing environments

        return false;

    }

    auto result = codec->startIncrementalDecode(bm.info(), bm.getPixels(), bm.rowBytes());

    if (result != SkCodec::kSuccess) {

        return false;

    }

    // Deliberately uninitialized to verify that incrementalDecode initializes it when it

    // returns kIncompleteInput or kErrorInInput.

    int rowsDecoded;

    result = codec->incrementalDecode(&rowsDecoded);

    switch (result) {

        case SkCodec::kIncompleteInput:

        case SkCodec::kErrorInInput:

            if (rowsDecoded < bm.height()) {

                void* dst = SkTAddOffset<void>(bm.getPixels(), rowsDecoded * bm.rowBytes());

                sk_bzero(dst, (bm.height() - rowsDecoded) * bm.rowBytes());

            }

            return true; // decoded a partial image

         case SkCodec::kSuccess:

            return true;

         default:

            return false;

    }

}

// TODO(kjlubick): remove IS_FUZZING... after https://crrev.com/c/2410304 lands

#if defined(SK_BUILD_FOR_LIBFUZZER) || defined(IS_FUZZING_WITH_LIBFUZZER)

extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {

    if (size > 10240) {

        return 0;

    }

    auto bytes = SkData::MakeWithoutCopy(data, size);

    FuzzIncrementalImageDecode(bytes);

    return 0;

}

#endif