// Copyright (c) 2013-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "hash.h"

#include "crypto/common.h"
#include "crypto/hmac_sha512.h"
#include "pubkey.h"

#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wold-style-cast"
#pragma clang diagnostic ignored "-Wsign-conversion"
#pragma clang diagnostic ignored "-Wshorten-64-to-32"
#pragma clang diagnostic ignored "-Wunused-parameter"
#endif

namespace bitcoin {

inline uint32_t ROTL32(uint32_t x, int8_t r) {
    return (x << r) | (x >> (32 - r));
}

uint32_t MurmurHash3(uint32_t nHashSeed,
                     const std::vector<uint8_t> &vDataToHash) {
    // The following is MurmurHash3 (x86_32), see
    // http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp
    uint32_t h1 = nHashSeed;
    if (vDataToHash.size() > 0) {
        const uint32_t c1 = 0xcc9e2d51;
        const uint32_t c2 = 0x1b873593;

        const int nblocks = vDataToHash.size() / 4;

        //----------
        // body
        const uint8_t *blocks = &vDataToHash[0] + nblocks * 4;

        for (int i = -nblocks; i; i++) {
            uint32_t k1 = ReadLE32(blocks + i * 4);

            k1 *= c1;
            k1 = ROTL32(k1, 15);
            k1 *= c2;

            h1 ^= k1;
            h1 = ROTL32(h1, 13);
            h1 = h1 * 5 + 0xe6546b64;
        }

        //----------
        // tail
        const uint8_t *tail = (const uint8_t *)(&vDataToHash[0] + nblocks * 4);

        uint32_t k1 = 0;

        switch (vDataToHash.size() & 3) {
            case 3:
                k1 ^= tail[2] << 16;
            [[fallthrough]];
            // FALLTHROUGH
            case 2:
                k1 ^= tail[1] << 8;
            [[fallthrough]];
            // FALLTHROUGH
            case 1:
                k1 ^= tail[0];
                k1 *= c1;
                k1 = ROTL32(k1, 15);
                k1 *= c2;
                h1 ^= k1;
        }
    }

    //----------
    // finalization
    h1 ^= vDataToHash.size();
    h1 ^= h1 >> 16;
    h1 *= 0x85ebca6b;
    h1 ^= h1 >> 13;
    h1 *= 0xc2b2ae35;
    h1 ^= h1 >> 16;

    return h1;
}


void BIP32Hash(const ChainCode &chainCode, uint32_t nChild, uint8_t header,
               const uint8_t data[32], uint8_t output[64]) {
    uint8_t num[4];
    num[0] = (nChild >> 24) & 0xFF;
    num[1] = (nChild >> 16) & 0xFF;
    num[2] = (nChild >> 8) & 0xFF;
    num[3] = (nChild >> 0) & 0xFF;
    CHMAC_SHA512(chainCode.begin(), chainCode.size())
        .Write(&header, 1)
        .Write(data, 32)
        .Write(num, 4)
        .Finalize(output);
}


} // end namespace bitcoin

#ifdef __clang__
#pragma clang diagnostic pop
#endif