// Copyright (c) 2014-present 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 <crypto/sha1.h>

#include <crypto/common.h>

#include <cstring>

// Internal implementation code.

namespace

{

/// Internal SHA-1 implementation.

namespace sha1

{

/** One round of SHA-1. */

void inline Round(uint32_t a, uint32_t& b, uint32_t c, uint32_t d, uint32_t& e, uint32_t f, uint32_t k, uint32_t w)

{

    e += ((a << 5) | (a >> 27)) + f + k + w;

    b = (b << 30) | (b >> 2);

}

uint32_t inline f1(uint32_t b, uint32_t c, uint32_t d) { return d ^ (b & (c ^ d)); }

uint32_t inline f2(uint32_t b, uint32_t c, uint32_t d) { return b ^ c ^ d; }

uint32_t inline f3(uint32_t b, uint32_t c, uint32_t d) { return (b & c) | (d & (b | c)); }

uint32_t inline left(uint32_t x) { return (x << 1) | (x >> 31); }

/** Initialize SHA-1 state. */

void inline Initialize(uint32_t* s)

{

    s[0] = 0x67452301ul;

    s[1] = 0xEFCDAB89ul;

    s[2] = 0x98BADCFEul;

    s[3] = 0x10325476ul;

    s[4] = 0xC3D2E1F0ul;

}

const uint32_t k1 = 0x5A827999ul;

const uint32_t k2 = 0x6ED9EBA1ul;

const uint32_t k3 = 0x8F1BBCDCul;

const uint32_t k4 = 0xCA62C1D6ul;

/** Perform a SHA-1 transformation, processing a 64-byte chunk. */

void Transform(uint32_t* s, const unsigned char* chunk)

{

    uint32_t a = s[0], b = s[1], c = s[2], d = s[3], e = s[4];

    uint32_t w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15;

    Round(a, b, c, d, e, f1(b, c, d), k1, w0 = ReadBE32(chunk + 0));

    Round(e, a, b, c, d, f1(a, b, c), k1, w1 = ReadBE32(chunk + 4));

    Round(d, e, a, b, c, f1(e, a, b), k1, w2 = ReadBE32(chunk + 8));

    Round(c, d, e, a, b, f1(d, e, a), k1, w3 = ReadBE32(chunk + 12));

    Round(b, c, d, e, a, f1(c, d, e), k1, w4 = ReadBE32(chunk + 16));

    Round(a, b, c, d, e, f1(b, c, d), k1, w5 = ReadBE32(chunk + 20));

    Round(e, a, b, c, d, f1(a, b, c), k1, w6 = ReadBE32(chunk + 24));

    Round(d, e, a, b, c, f1(e, a, b), k1, w7 = ReadBE32(chunk + 28));

    Round(c, d, e, a, b, f1(d, e, a), k1, w8 = ReadBE32(chunk + 32));

    Round(b, c, d, e, a, f1(c, d, e), k1, w9 = ReadBE32(chunk + 36));

    Round(a, b, c, d, e, f1(b, c, d), k1, w10 = ReadBE32(chunk + 40));

    Round(e, a, b, c, d, f1(a, b, c), k1, w11 = ReadBE32(chunk + 44));

    Round(d, e, a, b, c, f1(e, a, b), k1, w12 = ReadBE32(chunk + 48));

    Round(c, d, e, a, b, f1(d, e, a), k1, w13 = ReadBE32(chunk + 52));

    Round(b, c, d, e, a, f1(c, d, e), k1, w14 = ReadBE32(chunk + 56));

    Round(a, b, c, d, e, f1(b, c, d), k1, w15 = ReadBE32(chunk + 60));

    Round(e, a, b, c, d, f1(a, b, c), k1, w0 = left(w0 ^ w13 ^ w8 ^ w2));

    Round(d, e, a, b, c, f1(e, a, b), k1, w1 = left(w1 ^ w14 ^ w9 ^ w3));

    Round(c, d, e, a, b, f1(d, e, a), k1, w2 = left(w2 ^ w15 ^ w10 ^ w4));

    Round(b, c, d, e, a, f1(c, d, e), k1, w3 = left(w3 ^ w0 ^ w11 ^ w5));

    Round(a, b, c, d, e, f2(b, c, d), k2, w4 = left(w4 ^ w1 ^ w12 ^ w6));

    Round(e, a, b, c, d, f2(a, b, c), k2, w5 = left(w5 ^ w2 ^ w13 ^ w7));

    Round(d, e, a, b, c, f2(e, a, b), k2, w6 = left(w6 ^ w3 ^ w14 ^ w8));

    Round(c, d, e, a, b, f2(d, e, a), k2, w7 = left(w7 ^ w4 ^ w15 ^ w9));

    Round(b, c, d, e, a, f2(c, d, e), k2, w8 = left(w8 ^ w5 ^ w0 ^ w10));

    Round(a, b, c, d, e, f2(b, c, d), k2, w9 = left(w9 ^ w6 ^ w1 ^ w11));

    Round(e, a, b, c, d, f2(a, b, c), k2, w10 = left(w10 ^ w7 ^ w2 ^ w12));

    Round(d, e, a, b, c, f2(e, a, b), k2, w11 = left(w11 ^ w8 ^ w3 ^ w13));

    Round(c, d, e, a, b, f2(d, e, a), k2, w12 = left(w12 ^ w9 ^ w4 ^ w14));

    Round(b, c, d, e, a, f2(c, d, e), k2, w13 = left(w13 ^ w10 ^ w5 ^ w15));

    Round(a, b, c, d, e, f2(b, c, d), k2, w14 = left(w14 ^ w11 ^ w6 ^ w0));

    Round(e, a, b, c, d, f2(a, b, c), k2, w15 = left(w15 ^ w12 ^ w7 ^ w1));

    Round(d, e, a, b, c, f2(e, a, b), k2, w0 = left(w0 ^ w13 ^ w8 ^ w2));

    Round(c, d, e, a, b, f2(d, e, a), k2, w1 = left(w1 ^ w14 ^ w9 ^ w3));

    Round(b, c, d, e, a, f2(c, d, e), k2, w2 = left(w2 ^ w15 ^ w10 ^ w4));

    Round(a, b, c, d, e, f2(b, c, d), k2, w3 = left(w3 ^ w0 ^ w11 ^ w5));

    Round(e, a, b, c, d, f2(a, b, c), k2, w4 = left(w4 ^ w1 ^ w12 ^ w6));

    Round(d, e, a, b, c, f2(e, a, b), k2, w5 = left(w5 ^ w2 ^ w13 ^ w7));

    Round(c, d, e, a, b, f2(d, e, a), k2, w6 = left(w6 ^ w3 ^ w14 ^ w8));

    Round(b, c, d, e, a, f2(c, d, e), k2, w7 = left(w7 ^ w4 ^ w15 ^ w9));

    Round(a, b, c, d, e, f3(b, c, d), k3, w8 = left(w8 ^ w5 ^ w0 ^ w10));

    Round(e, a, b, c, d, f3(a, b, c), k3, w9 = left(w9 ^ w6 ^ w1 ^ w11));

    Round(d, e, a, b, c, f3(e, a, b), k3, w10 = left(w10 ^ w7 ^ w2 ^ w12));

    Round(c, d, e, a, b, f3(d, e, a), k3, w11 = left(w11 ^ w8 ^ w3 ^ w13));

    Round(b, c, d, e, a, f3(c, d, e), k3, w12 = left(w12 ^ w9 ^ w4 ^ w14));

    Round(a, b, c, d, e, f3(b, c, d), k3, w13 = left(w13 ^ w10 ^ w5 ^ w15));

    Round(e, a, b, c, d, f3(a, b, c), k3, w14 = left(w14 ^ w11 ^ w6 ^ w0));

    Round(d, e, a, b, c, f3(e, a, b), k3, w15 = left(w15 ^ w12 ^ w7 ^ w1));

    Round(c, d, e, a, b, f3(d, e, a), k3, w0 = left(w0 ^ w13 ^ w8 ^ w2));

    Round(b, c, d, e, a, f3(c, d, e), k3, w1 = left(w1 ^ w14 ^ w9 ^ w3));

    Round(a, b, c, d, e, f3(b, c, d), k3, w2 = left(w2 ^ w15 ^ w10 ^ w4));

    Round(e, a, b, c, d, f3(a, b, c), k3, w3 = left(w3 ^ w0 ^ w11 ^ w5));

    Round(d, e, a, b, c, f3(e, a, b), k3, w4 = left(w4 ^ w1 ^ w12 ^ w6));

    Round(c, d, e, a, b, f3(d, e, a), k3, w5 = left(w5 ^ w2 ^ w13 ^ w7));

    Round(b, c, d, e, a, f3(c, d, e), k3, w6 = left(w6 ^ w3 ^ w14 ^ w8));

    Round(a, b, c, d, e, f3(b, c, d), k3, w7 = left(w7 ^ w4 ^ w15 ^ w9));

    Round(e, a, b, c, d, f3(a, b, c), k3, w8 = left(w8 ^ w5 ^ w0 ^ w10));

    Round(d, e, a, b, c, f3(e, a, b), k3, w9 = left(w9 ^ w6 ^ w1 ^ w11));

    Round(c, d, e, a, b, f3(d, e, a), k3, w10 = left(w10 ^ w7 ^ w2 ^ w12));

    Round(b, c, d, e, a, f3(c, d, e), k3, w11 = left(w11 ^ w8 ^ w3 ^ w13));

    Round(a, b, c, d, e, f2(b, c, d), k4, w12 = left(w12 ^ w9 ^ w4 ^ w14));

    Round(e, a, b, c, d, f2(a, b, c), k4, w13 = left(w13 ^ w10 ^ w5 ^ w15));

    Round(d, e, a, b, c, f2(e, a, b), k4, w14 = left(w14 ^ w11 ^ w6 ^ w0));

    Round(c, d, e, a, b, f2(d, e, a), k4, w15 = left(w15 ^ w12 ^ w7 ^ w1));

    Round(b, c, d, e, a, f2(c, d, e), k4, w0 = left(w0 ^ w13 ^ w8 ^ w2));

    Round(a, b, c, d, e, f2(b, c, d), k4, w1 = left(w1 ^ w14 ^ w9 ^ w3));

    Round(e, a, b, c, d, f2(a, b, c), k4, w2 = left(w2 ^ w15 ^ w10 ^ w4));

    Round(d, e, a, b, c, f2(e, a, b), k4, w3 = left(w3 ^ w0 ^ w11 ^ w5));

    Round(c, d, e, a, b, f2(d, e, a), k4, w4 = left(w4 ^ w1 ^ w12 ^ w6));

    Round(b, c, d, e, a, f2(c, d, e), k4, w5 = left(w5 ^ w2 ^ w13 ^ w7));

    Round(a, b, c, d, e, f2(b, c, d), k4, w6 = left(w6 ^ w3 ^ w14 ^ w8));

    Round(e, a, b, c, d, f2(a, b, c), k4, w7 = left(w7 ^ w4 ^ w15 ^ w9));

    Round(d, e, a, b, c, f2(e, a, b), k4, w8 = left(w8 ^ w5 ^ w0 ^ w10));

    Round(c, d, e, a, b, f2(d, e, a), k4, w9 = left(w9 ^ w6 ^ w1 ^ w11));

    Round(b, c, d, e, a, f2(c, d, e), k4, w10 = left(w10 ^ w7 ^ w2 ^ w12));

    Round(a, b, c, d, e, f2(b, c, d), k4, w11 = left(w11 ^ w8 ^ w3 ^ w13));

    Round(e, a, b, c, d, f2(a, b, c), k4, w12 = left(w12 ^ w9 ^ w4 ^ w14));

    Round(d, e, a, b, c, f2(e, a, b), k4, left(w13 ^ w10 ^ w5 ^ w15));

    Round(c, d, e, a, b, f2(d, e, a), k4, left(w14 ^ w11 ^ w6 ^ w0));

    Round(b, c, d, e, a, f2(c, d, e), k4, left(w15 ^ w12 ^ w7 ^ w1));

    s[0] += a;

    s[1] += b;

    s[2] += c;

    s[3] += d;

    s[4] += e;

}

} // namespace sha1

} // namespace

////// SHA1

CSHA1::CSHA1()

{

    sha1::Initialize(s);

}

CSHA1& CSHA1::Write(const unsigned char* data, size_t len)

{

    const unsigned char* end = data + len;

    size_t bufsize = bytes % 64;

    if (bufsize && bufsize + len >= 64) {

        // Fill the buffer, and process it.

        memcpy(buf + bufsize, data, 64 - bufsize);

        bytes += 64 - bufsize;

        data += 64 - bufsize;

        sha1::Transform(s, buf);

        bufsize = 0;

    }

    while (end - data >= 64) {

        // Process full chunks directly from the source.

        sha1::Transform(s, data);

        bytes += 64;

        data += 64;

    }

    if (end > data) {

        // Fill the buffer with what remains.

        memcpy(buf + bufsize, data, end - data);

        bytes += end - data;

    }

    return *this;

}

void CSHA1::Finalize(unsigned char hash[OUTPUT_SIZE])

{

    static const unsigned char pad[64] = {0x80};

    unsigned char sizedesc[8];

    WriteBE64(sizedesc, bytes << 3);

    Write(pad, 1 + ((119 - (bytes % 64)) % 64));

    Write(sizedesc, 8);

    WriteBE32(hash, s[0]);

    WriteBE32(hash + 4, s[1]);

    WriteBE32(hash + 8, s[2]);

    WriteBE32(hash + 12, s[3]);

    WriteBE32(hash + 16, s[4]);

}

CSHA1& CSHA1::Reset()

{

    bytes = 0;

    sha1::Initialize(s);

    return *this;

}