/*
 * This file is part of the Flowee project
 * Copyright (C) 2014 The Bitcoin Core developers
 * Copyright (C) 2019 Tom Zander <tom@flowee.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef FLOWEE_CRYPTO_SHA256_H
#define FLOWEE_CRYPTO_SHA256_H

#include <cstdint>
#include <cassert>
#include <string>

/** A hasher class for SHA-256. */
class CSHA256
{
private:
    uint32_t s[8];
    unsigned char buf[64];
    uint64_t bytes;

public:
    static const size_t OUTPUT_SIZE = 32;

    CSHA256();
    inline CSHA256& Write(const char* data, int len) {
        assert(len >= 0);
        return Write(reinterpret_cast<const unsigned char*>(data), size_t(len));
    }
    CSHA256& Write(const unsigned char* data, size_t len);
    inline void Finalize(char *hash) {
        return Finalize(reinterpret_cast<unsigned char*>(hash));
    }
    void Finalize(unsigned char *hash);
    CSHA256& Reset();
};

/** Autodetect the best available SHA256 implementation.
 *  Returns the name of the implementation.
 */
std::string SHA256AutoDetect();

/** Compute multiple double-SHA256's of 64-byte blobs.
 *  output:  pointer to a blocks*32 byte output buffer
 *  input:   pointer to a blocks*64 byte input buffer
 *  blocks:  the number of hashes to compute.
 */
void SHA256D64(unsigned char* output, const unsigned char* input, size_t blocks);

#endif