HashContext.h

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/****
 * Sming Framework Project - Open Source framework for high efficiency native ESP8266 development.
 * Created 2015 by Skurydin Alexey
 * http://github.com/SmingHub/Sming
 * All files of the Sming Core are provided under the LGPL v3 license.
 *
 * HashContext.h
 *
 ****/

#pragma once

#include "HashEngine.h"
#include "Blob.h"
#include "ByteArray.h"

namespace Crypto
{
template <class Engine_> class HashContext
{
public:
    using Engine = Engine_;
    using Hash = ByteArray<Engine::hashsize>;

    struct State {
        ByteArray<Engine::statesize> value;
        uint64_t count;
    };

    HashContext()
    {
        reset();
    }

    HashContext& reset()
    {
        engine.init();
        return *this;
    }

    template <typename... Ts> Hash calculate(Ts&&... args)
    {
        update(std::forward<Ts>(args)...);
        return getHash();
    }

    HashContext& update(const Blob& blob)
    {
        return update(blob.data(), blob.size());
    }

    HashContext& update(const FSTR::ObjectBase& obj)
    {
        uint8_t buf[256];
        size_t offset = 0;
        size_t len;
        while((len = obj.read(offset, buf, sizeof(buf))) > 0) {
            engine.update(buf, len);
            offset += len;
        }
        return *this;
    }

    HashContext& update(const void* data, size_t size)
    {
        engine.update(data, size);
        return *this;
    }

    template <size_t size_> HashContext& update(const ByteArray<size_>& array)
    {
        return update(array.data(), array.size());
    }
    Hash getHash()
    {
        Hash hash;
        engine.final(hash.data());
        return hash;
    }

    State getState()
    {
        State state;
        state.count = engine.get_state(state.value.data());
        return state;
    }

    void setState(const State& state)
    {
        engine.set_state(state.value.data(), state.count);
    }

private:
    Engine engine;
};

/*
 * Context definitions
 */

using Md5 = HashContext<Md5Engine>;
using Sha1 = HashContext<Sha1Engine>;
using Sha224 = HashContext<Sha224Engine>;
using Sha256 = HashContext<Sha256Engine>;
using Sha384 = HashContext<Sha384Engine>;
using Sha512 = HashContext<Sha512Engine>;

} // namespace Crypto