// Copyright (c) 2009-2010 Satoshi Nakamoto

// Copyright (c) 2009-2022 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 <arith_uint256.h>

#include <uint256.h>

#include <crypto/common.h>

#include <cassert>

template <unsigned int BITS>

base_uint<BITS>& base_uint<BITS>::operator<<=(unsigned int shift)

{

    base_uint<BITS> a(*this);

    for (int i = 0; i < WIDTH; i++)

        pn[i] = 0;

    int k = shift / 32;

    shift = shift % 32;

    for (int i = 0; i < WIDTH; i++) {

        if (i + k + 1 < WIDTH && shift != 0)

            pn[i + k + 1] |= (a.pn[i] >> (32 - shift));

        if (i + k < WIDTH)

            pn[i + k] |= (a.pn[i] << shift);

    }

    return *this;

}

Unexecuted instantiation: _ZN9base_uintILj256EElSEj

Unexecuted instantiation: _ZN9base_uintILj6144EElSEj

template <unsigned int BITS>

base_uint<BITS>& base_uint<BITS>::operator>>=(unsigned int shift)

{

    base_uint<BITS> a(*this);

    for (int i = 0; i < WIDTH; i++)

        pn[i] = 0;

    int k = shift / 32;

    shift = shift % 32;

    for (int i = 0; i < WIDTH; i++) {

        if (i - k - 1 >= 0 && shift != 0)

            pn[i - k - 1] |= (a.pn[i] << (32 - shift));

        if (i - k >= 0)

            pn[i - k] |= (a.pn[i] >> shift);

    }

    return *this;

}

Unexecuted instantiation: _ZN9base_uintILj256EErSEj

Unexecuted instantiation: _ZN9base_uintILj6144EErSEj

template <unsigned int BITS>

base_uint<BITS>& base_uint<BITS>::operator*=(uint32_t b32)

{

    uint64_t carry = 0;

    for (int i = 0; i < WIDTH; i++) {

        uint64_t n = carry + (uint64_t)b32 * pn[i];

        pn[i] = n & 0xffffffff;

        carry = n >> 32;

    }

    return *this;

}

template <unsigned int BITS>

base_uint<BITS>& base_uint<BITS>::operator*=(const base_uint& b)

{

    base_uint<BITS> a;

    for (int j = 0; j < WIDTH; j++) {

        uint64_t carry = 0;

        for (int i = 0; i + j < WIDTH; i++) {

            uint64_t n = carry + a.pn[i + j] + (uint64_t)pn[j] * b.pn[i];

            a.pn[i + j] = n & 0xffffffff;

            carry = n >> 32;

        }

    }

    *this = a;

    return *this;

}

Unexecuted instantiation: _ZN9base_uintILj256EEmLERKS0_

Unexecuted instantiation: _ZN9base_uintILj6144EEmLERKS0_

template <unsigned int BITS>

base_uint<BITS>& base_uint<BITS>::operator/=(const base_uint& b)

{

    base_uint<BITS> div = b;     // make a copy, so we can shift.

    base_uint<BITS> num = *this; // make a copy, so we can subtract.

    *this = 0;                   // the quotient.

    int num_bits = num.bits();

    int div_bits = div.bits();

    if (div_bits == 0)

        throw uint_error("Division by zero");

    if (div_bits > num_bits) // the result is certainly 0.

        return *this;

    int shift = num_bits - div_bits;

    div <<= shift; // shift so that div and num align.

    while (shift >= 0) {

        if (num >= div) {

            num -= div;

            pn[shift / 32] |= (1U << (shift & 31)); // set a bit of the result.

        }

        div >>= 1; // shift back.

        shift--;

    }

    // num now contains the remainder of the division.

    return *this;

}

Unexecuted instantiation: _ZN9base_uintILj256EEdVERKS0_

Unexecuted instantiation: _ZN9base_uintILj6144EEdVERKS0_

template <unsigned int BITS>

int base_uint<BITS>::CompareTo(const base_uint<BITS>& b) const

{

    for (int i = WIDTH - 1; i >= 0; i--) {

        if (pn[i] < b.pn[i])

            return -1;

        if (pn[i] > b.pn[i])

            return 1;

    }

    return 0;

}

Unexecuted instantiation: _ZNK9base_uintILj256EE9CompareToERKS0_

Unexecuted instantiation: _ZNK9base_uintILj6144EE9CompareToERKS0_

template <unsigned int BITS>

bool base_uint<BITS>::EqualTo(uint64_t b) const

{

    for (int i = WIDTH - 1; i >= 2; i--) {

        if (pn[i])

            return false;

    }

    if (pn[1] != (b >> 32))

        return false;

    if (pn[0] != (b & 0xfffffffful))

        return false;

    return true;

}

template <unsigned int BITS>

double base_uint<BITS>::getdouble() const

{

    double ret = 0.0;

    double fact = 1.0;

    for (int i = 0; i < WIDTH; i++) {

        ret += fact * pn[i];

        fact *= 4294967296.0;

    }

    return ret;

}

template <unsigned int BITS>

std::string base_uint<BITS>::GetHex() const

{

    base_blob<BITS> b;

    for (int x = 0; x < this->WIDTH; ++x) {

        WriteLE32(b.begin() + x*4, this->pn[x]);

    }

    return b.GetHex();

}

template <unsigned int BITS>

std::string base_uint<BITS>::ToString() const

{

    return GetHex();

}

template <unsigned int BITS>

unsigned int base_uint<BITS>::bits() const

{

    for (int pos = WIDTH - 1; pos >= 0; pos--) {

        if (pn[pos]) {

            for (int nbits = 31; nbits > 0; nbits--) {

                if (pn[pos] & 1U << nbits)

                    return 32 * pos + nbits + 1;

            }

            return 32 * pos + 1;

        }

    }

    return 0;

}

Unexecuted instantiation: _ZNK9base_uintILj256EE4bitsEv

Unexecuted instantiation: _ZNK9base_uintILj6144EE4bitsEv

// Explicit instantiations for base_uint<256>

template class base_uint<256>;

// This implementation directly uses shifts instead of going

// through an intermediate MPI representation.

arith_uint256& arith_uint256::SetCompact(uint32_t nCompact, bool* pfNegative, bool* pfOverflow)

{

    int nSize = nCompact >> 24;

    uint32_t nWord = nCompact & 0x007fffff;

    if (nSize <= 3) {

        nWord >>= 8 * (3 - nSize);

        *this = nWord;

    } else {

        *this = nWord;

        *this <<= 8 * (nSize - 3);

    }

    if (pfNegative)

        *pfNegative = nWord != 0 && (nCompact & 0x00800000) != 0;

    if (pfOverflow)

        *pfOverflow = nWord != 0 && ((nSize > 34) ||

                                     (nWord > 0xff && nSize > 33) ||

                                     (nWord > 0xffff && nSize > 32));

    return *this;

}

uint32_t arith_uint256::GetCompact(bool fNegative) const

{

    int nSize = (bits() + 7) / 8;

    uint32_t nCompact = 0;

    if (nSize <= 3) {

        nCompact = GetLow64() << 8 * (3 - nSize);

    } else {

        arith_uint256 bn = *this >> 8 * (nSize - 3);

        nCompact = bn.GetLow64();

    }

    // The 0x00800000 bit denotes the sign.

    // Thus, if it is already set, divide the mantissa by 256 and increase the exponent.

    if (nCompact & 0x00800000) {

        nCompact >>= 8;

        nSize++;

    }

    assert((nCompact & ~0x007fffffU) == 0);

    assert(nSize < 256);

    nCompact |= nSize << 24;

    nCompact |= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0);

    return nCompact;

}

uint256 ArithToUint256(const arith_uint256 &a)

{

    uint256 b;

    for(int x=0; x<a.WIDTH; ++x)

        WriteLE32(b.begin() + x*4, a.pn[x]);

    return b;

}

arith_uint256 UintToArith256(const uint256 &a)

{

    arith_uint256 b;

    for(int x=0; x<b.WIDTH; ++x)

        b.pn[x] = ReadLE32(a.begin() + x*4);

    return b;

}

// Explicit instantiations for base_uint<6144> (used in test/fuzz/muhash.cpp).

template base_uint<6144>& base_uint<6144>::operator*=(const base_uint<6144>& b);

template base_uint<6144>& base_uint<6144>::operator/=(const base_uint<6144>& b);