/*
 * Copyright (C) 2021 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include "DaemonCoders.h"

namespace WebKit::Daemon {

class Decoder {
public:
    Decoder(std::span<const uint8_t> buffer)
        : m_buffer(buffer) { }
    ~Decoder();

    template<typename T>
    Decoder& operator>>(std::optional<T>& t)
    {
        t = decode<T>();
        return *this;
    }

    template<typename T>
    std::optional<T> decode()
    {
        return Coder<std::remove_cvref_t<T>>::decode(*this);
    }

    template<typename T>
    WARN_UNUSED_RETURN bool bufferIsLargeEnoughToContain(size_t numElements) const
    {
        static_assert(std::is_arithmetic<T>::value, "Type T must have a fixed, known encoded size!");

        if (numElements > std::numeric_limits<size_t>::max() / sizeof(T))
            return false;

        return bufferIsLargeEnoughToContainBytes(numElements * sizeof(T));
    }

    WARN_UNUSED_RETURN bool decodeFixedLengthData(uint8_t* data, size_t);
    std::span<const uint8_t> decodeFixedLengthReference(size_t);

private:
    WARN_UNUSED_RETURN bool bufferIsLargeEnoughToContainBytes(size_t) const;

    std::span<const uint8_t> m_buffer;
    size_t m_bufferPosition { 0 };
};

} // namespace WebKit::Daemon
