[VerusCoin.git] / src / arith_uint256.cpp

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://www.opensource.org/licenses/mit-license.php .

#include "arith_uint256.h"

#include "uint256.h"
#include "utilstrencodings.h"
#include "crypto/common.h"

#include <stdio.h>
#include <string.h>

template <unsigned int BITS>
base_uint<BITS>::base_uint(const std::string& str)
{
    SetHex(str);
}

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;
}

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;
}

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 = *this;
    *this = 0;
    for (int j = 0; j < WIDTH; j++) {
        uint64_t carry = 0;
        for (int i = 0; i + j < WIDTH; i++) {
            uint64_t n = carry + pn[i + j] + (uint64_t)a.pn[j] * b.pn[i];
            pn[i + j] = 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> 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] |= (1 << (shift & 31)); // set a bit of the result.
        }
        div >>= 1; // shift back.
        shift--;
    }
    // num now contains the remainder of the division.
    return *this;
}

template <unsigned int BITS>
int base_uint<BITS>::CompareTo(const base_uint<BITS>& b) const
{
    if ( (uint64_t)pn < 0x1000 || (uint64_t)b.pn <= 0x1000 )
    {
        //fprintf(stderr,"CompareTo null %p or %p\n",pn,b.pn);
        return(0);
    }
    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;
}

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
{
    return ArithToUint256(*this).GetHex();
}

template <unsigned int BITS>
void base_uint<BITS>::SetHex(const char* psz)
{
    *this = UintToArith256(uint256S(psz));
}

template <unsigned int BITS>
void base_uint<BITS>::SetHex(const std::string& str)
{
    SetHex(str.c_str());
}

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 (size_t bits = 31; bits > 0; bits--) {
                if (pn[pos] & (1U << bits)) {
                    return 32 * pos + bits + 1;
                }
            }
            return 32 * pos + 1;
        }
    }
    return 0;
}

// Explicit instantiations for base_uint<256>
template base_uint<256>::base_uint(const std::string&);
template base_uint<256>& base_uint<256>::operator<<=(unsigned int);
template base_uint<256>& base_uint<256>::operator>>=(unsigned int);
template base_uint<256>& base_uint<256>::operator*=(uint32_t b32);
template base_uint<256>& base_uint<256>::operator*=(const base_uint<256>& b);
template base_uint<256>& base_uint<256>::operator/=(const base_uint<256>& b);
template int base_uint<256>::CompareTo(const base_uint<256>&) const;
template bool base_uint<256>::EqualTo(uint64_t) const;
template double base_uint<256>::getdouble() const;
template std::string base_uint<256>::GetHex() const;
template std::string base_uint<256>::ToString() const;
template void base_uint<256>::SetHex(const char*);
template void base_uint<256>::SetHex(const std::string&);
template unsigned int base_uint<256>::bits() const;

// 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 & ~0x007fffff) == 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;
}
Commit	Line	Data
bfc60703 WL	1	// Copyright (c) 2009-2010 Satoshi Nakamoto
	2	// Copyright (c) 2009-2014 The Bitcoin developers
	3	// Distributed under the MIT software license, see the accompanying
bc909a7a	4	// file COPYING or https://www.opensource.org/licenses/mit-license.php .
bfc60703 WL	5
	6	#include "arith_uint256.h"
	7
92cdb1aa	8	#include "uint256.h"
bfc60703	9	#include "utilstrencodings.h"
f4e64872	10	#include "crypto/common.h"
bfc60703 WL	11
	12	#include <stdio.h>
	13	#include <string.h>
	14
	15	template <unsigned int BITS>
	16	base_uint<BITS>::base_uint(const std::string& str)
	17	{
	18	SetHex(str);
	19	}
	20
bfc60703 WL	21	template <unsigned int BITS>
	22	base_uint<BITS>& base_uint<BITS>::operator<<=(unsigned int shift)
	23	{
	24	base_uint<BITS> a(*this);
	25	for (int i = 0; i < WIDTH; i++)
	26	pn[i] = 0;
	27	int k = shift / 32;
	28	shift = shift % 32;
	29	for (int i = 0; i < WIDTH; i++) {
	30	if (i + k + 1 < WIDTH && shift != 0)
	31	pn[i + k + 1] \|= (a.pn[i] >> (32 - shift));
	32	if (i + k < WIDTH)
	33	pn[i + k] \|= (a.pn[i] << shift);
	34	}
	35	return *this;
	36	}
	37
	38	template <unsigned int BITS>
	39	base_uint<BITS>& base_uint<BITS>::operator>>=(unsigned int shift)
	40	{
	41	base_uint<BITS> a(*this);
	42	for (int i = 0; i < WIDTH; i++)
	43	pn[i] = 0;
	44	int k = shift / 32;
	45	shift = shift % 32;
	46	for (int i = 0; i < WIDTH; i++) {
	47	if (i - k - 1 >= 0 && shift != 0)
	48	pn[i - k - 1] \|= (a.pn[i] << (32 - shift));
	49	if (i - k >= 0)
	50	pn[i - k] \|= (a.pn[i] >> shift);
	51	}
	52	return *this;
	53	}
	54
	55	template <unsigned int BITS>
	56	base_uint<BITS>& base_uint<BITS>::operator*=(uint32_t b32)
	57	{
	58	uint64_t carry = 0;
	59	for (int i = 0; i < WIDTH; i++) {
	60	uint64_t n = carry + (uint64_t)b32 * pn[i];
	61	pn[i] = n & 0xffffffff;
	62	carry = n >> 32;
	63	}
	64	return *this;
	65	}
	66
	67	template <unsigned int BITS>
	68	base_uint<BITS>& base_uint<BITS>::operator*=(const base_uint& b)
	69	{
	70	base_uint<BITS> a = *this;
	71	*this = 0;
	72	for (int j = 0; j < WIDTH; j++) {
	73	uint64_t carry = 0;
	74	for (int i = 0; i + j < WIDTH; i++) {
	75	uint64_t n = carry + pn[i + j] + (uint64_t)a.pn[j] * b.pn[i];
	76	pn[i + j] = n & 0xffffffff;
	77	carry = n >> 32;
	78	}
	79	}
	80	return *this;
	81	}
	82
	83	template <unsigned int BITS>
	84	base_uint<BITS>& base_uint<BITS>::operator/=(const base_uint& b)
85	{
86	base_uint<BITS> div = b; // make a copy, so we can shift.
87	base_uint<BITS> num = *this; // make a copy, so we can subtract.
88	*this = 0; // the quotient.
89	int num_bits = num.bits();
90	int div_bits = div.bits();
91	if (div_bits == 0)
92	throw uint_error("Division by zero");
93	if (div_bits > num_bits) // the result is certainly 0.
94	return *this;
95	int shift = num_bits - div_bits;
96	div <<= shift; // shift so that div and num align.
97	while (shift >= 0) {
98	if (num >= div) {
99	num -= div;
100	pn[shift / 32] \|= (1 << (shift & 31)); // set a bit of the result.
101	}
102	div >>= 1; // shift back.
103	shift--;
104	}
105	// num now contains the remainder of the division.
106	return *this;
107	}
108
109	template <unsigned int BITS>
110	int base_uint<BITS>::CompareTo(const base_uint<BITS>& b) const
111	{
e4f53bd2	112	if ( (uint64_t)pn < 0x1000 \|\| (uint64_t)b.pn <= 0x1000 )
88e117ad	113	{
007aca38	114	//fprintf(stderr,"CompareTo null %p or %p\n",pn,b.pn);
88e117ad	115	return(0);
88e117ad	116	}
bfc60703 WL	117	for (int i = WIDTH - 1; i >= 0; i--) {
	118	if (pn[i] < b.pn[i])
	119	return -1;
	120	if (pn[i] > b.pn[i])
	121	return 1;
	122	}
	123	return 0;
	124	}
	125
	126	template <unsigned int BITS>
	127	bool base_uint<BITS>::EqualTo(uint64_t b) const
	128	{
	129	for (int i = WIDTH - 1; i >= 2; i--) {
	130	if (pn[i])
	131	return false;
	132	}
	133	if (pn[1] != (b >> 32))
	134	return false;
	135	if (pn[0] != (b & 0xfffffffful))
	136	return false;
	137	return true;
	138	}
	139
	140	template <unsigned int BITS>
	141	double base_uint<BITS>::getdouble() const
	142	{
	143	double ret = 0.0;
	144	double fact = 1.0;
	145	for (int i = 0; i < WIDTH; i++) {
	146	ret += fact * pn[i];
	147	fact *= 4294967296.0;
	148	}
	149	return ret;
	150	}
	151
	152	template <unsigned int BITS>
	153	std::string base_uint<BITS>::GetHex() const
	154	{
6bd0dc2a	155	return ArithToUint256(*this).GetHex();
bfc60703 WL	156	}
	157
	158	template <unsigned int BITS>
	159	void base_uint<BITS>::SetHex(const char* psz)
	160	{
6bd0dc2a	161	*this = UintToArith256(uint256S(psz));
bfc60703 WL	162	}
	163
	164	template <unsigned int BITS>
	165	void base_uint<BITS>::SetHex(const std::string& str)
	166	{
	167	SetHex(str.c_str());
	168	}
	169
	170	template <unsigned int BITS>
	171	std::string base_uint<BITS>::ToString() const
	172	{
	173	return (GetHex());
	174	}
	175
	176	template <unsigned int BITS>
	177	unsigned int base_uint<BITS>::bits() const
	178	{
	179	for (int pos = WIDTH - 1; pos >= 0; pos--) {
	180	if (pn[pos]) {
ff405316 DA	181	for (size_t bits = 31; bits > 0; bits--) {
ff405316 DA	182	if (pn[pos] & (1U << bits)) {
bfc60703	183	return 32 * pos + bits + 1;
ff405316	184	}
bfc60703 WL	185	}
	186	return 32 * pos + 1;
	187	}
	188	}
	189	return 0;
	190	}
	191
bfc60703 WL	192	// Explicit instantiations for base_uint<256>
bfc60703 WL	193	template base_uint<256>::base_uint(const std::string&);
bfc60703 WL	194	template base_uint<256>& base_uint<256>::operator<<=(unsigned int);
	195	template base_uint<256>& base_uint<256>::operator>>=(unsigned int);
	196	template base_uint<256>& base_uint<256>::operator*=(uint32_t b32);
	197	template base_uint<256>& base_uint<256>::operator*=(const base_uint<256>& b);
	198	template base_uint<256>& base_uint<256>::operator/=(const base_uint<256>& b);
	199	template int base_uint<256>::CompareTo(const base_uint<256>&) const;
	200	template bool base_uint<256>::EqualTo(uint64_t) const;
	201	template double base_uint<256>::getdouble() const;
	202	template std::string base_uint<256>::GetHex() const;
	203	template std::string base_uint<256>::ToString() const;
	204	template void base_uint<256>::SetHex(const char*);
	205	template void base_uint<256>::SetHex(const std::string&);
	206	template unsigned int base_uint<256>::bits() const;
	207
	208	// This implementation directly uses shifts instead of going
	209	// through an intermediate MPI representation.
	210	arith_uint256& arith_uint256::SetCompact(uint32_t nCompact, bool* pfNegative, bool* pfOverflow)
	211	{
	212	int nSize = nCompact >> 24;
	213	uint32_t nWord = nCompact & 0x007fffff;
	214	if (nSize <= 3) {
	215	nWord >>= 8 * (3 - nSize);
	216	*this = nWord;
	217	} else {
	218	*this = nWord;
	219	this <<= 8 (nSize - 3);
	220	}
	221	if (pfNegative)
	222	*pfNegative = nWord != 0 && (nCompact & 0x00800000) != 0;
	223	if (pfOverflow)
	224	*pfOverflow = nWord != 0 && ((nSize > 34) \|\|
	225	(nWord > 0xff && nSize > 33) \|\|
	226	(nWord > 0xffff && nSize > 32));
	227	return *this;
	228	}
	229
	230	uint32_t arith_uint256::GetCompact(bool fNegative) const
	231	{
	232	int nSize = (bits() + 7) / 8;
	233	uint32_t nCompact = 0;
	234	if (nSize <= 3) {
	235	nCompact = GetLow64() << 8 * (3 - nSize);
	236	} else {
	237	arith_uint256 bn = this >> 8 (nSize - 3);
	238	nCompact = bn.GetLow64();
	239	}
	240	// The 0x00800000 bit denotes the sign.
	241	// Thus, if it is already set, divide the mantissa by 256 and increase the exponent.
	242	if (nCompact & 0x00800000) {
	243	nCompact >>= 8;
	244	nSize++;
	245	}
	246	assert((nCompact & ~0x007fffff) == 0);
	247	assert(nSize < 256);
	248	nCompact \|= nSize << 24;
	249	nCompact \|= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0);
	250	return nCompact;
	251	}
	252
92cdb1aa WL	253	uint256 ArithToUint256(const arith_uint256 &a)
	254	{
	255	uint256 b;
f4e64872 WL	256	for(int x=0; x<a.WIDTH; ++x)
f4e64872 WL	257	WriteLE32(b.begin() + x*4, a.pn[x]);
92cdb1aa WL	258	return b;
	259	}
	260	arith_uint256 UintToArith256(const uint256 &a)
	261	{
	262	arith_uint256 b;
f4e64872 WL	263	for(int x=0; x<b.WIDTH; ++x)
f4e64872 WL	264	b.pn[x] = ReadLE32(a.begin() + x*4);
92cdb1aa WL	265	return b;
92cdb1aa WL	266	}