[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 http://www.opensource.org/licenses/mit-license.php.

#include "arith_uint256.h"

#include "uint256.h"
#include "utilstrencodings.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
{
    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 (int bits = 31; bits > 0; bits--) {
                if (pn[pos] & 1 << 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;
    // TODO: needs bswap32 on big-endian
    memcpy(b.begin(), a.pn, a.size());
    return b;
}
arith_uint256 UintToArith256(const uint256 &a)
{
    arith_uint256 b;
    // TODO: needs bswap32 on big-endian
    memcpy(b.pn, a.begin(), a.size());
    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
	4	// file COPYING or http://www.opensource.org/licenses/mit-license.php.
	5
	6	#include "arith_uint256.h"
	7
92cdb1aa	8	#include "uint256.h"
bfc60703 WL	9	#include "utilstrencodings.h"
	10
	11	#include <stdio.h>
	12	#include <string.h>
	13
	14	template <unsigned int BITS>
	15	base_uint<BITS>::base_uint(const std::string& str)
	16	{
	17	SetHex(str);
	18	}
	19
bfc60703 WL	20	template <unsigned int BITS>
	21	base_uint<BITS>& base_uint<BITS>::operator<<=(unsigned int shift)
	22	{
	23	base_uint<BITS> a(*this);
	24	for (int i = 0; i < WIDTH; i++)
	25	pn[i] = 0;
	26	int k = shift / 32;
	27	shift = shift % 32;
	28	for (int i = 0; i < WIDTH; i++) {
	29	if (i + k + 1 < WIDTH && shift != 0)
	30	pn[i + k + 1] \|= (a.pn[i] >> (32 - shift));
	31	if (i + k < WIDTH)
	32	pn[i + k] \|= (a.pn[i] << shift);
	33	}
	34	return *this;
	35	}
	36
	37	template <unsigned int BITS>
	38	base_uint<BITS>& base_uint<BITS>::operator>>=(unsigned int shift)
	39	{
	40	base_uint<BITS> a(*this);
	41	for (int i = 0; i < WIDTH; i++)
	42	pn[i] = 0;
	43	int k = shift / 32;
	44	shift = shift % 32;
	45	for (int i = 0; i < WIDTH; i++) {
	46	if (i - k - 1 >= 0 && shift != 0)
	47	pn[i - k - 1] \|= (a.pn[i] << (32 - shift));
	48	if (i - k >= 0)
	49	pn[i - k] \|= (a.pn[i] >> shift);
	50	}
	51	return *this;
	52	}
	53
	54	template <unsigned int BITS>
	55	base_uint<BITS>& base_uint<BITS>::operator*=(uint32_t b32)
	56	{
	57	uint64_t carry = 0;
	58	for (int i = 0; i < WIDTH; i++) {
	59	uint64_t n = carry + (uint64_t)b32 * pn[i];
	60	pn[i] = n & 0xffffffff;
	61	carry = n >> 32;
	62	}
	63	return *this;
	64	}
	65
	66	template <unsigned int BITS>
	67	base_uint<BITS>& base_uint<BITS>::operator*=(const base_uint& b)
	68	{
	69	base_uint<BITS> a = *this;
	70	*this = 0;
	71	for (int j = 0; j < WIDTH; j++) {
	72	uint64_t carry = 0;
	73	for (int i = 0; i + j < WIDTH; i++) {
	74	uint64_t n = carry + pn[i + j] + (uint64_t)a.pn[j] * b.pn[i];
	75	pn[i + j] = n & 0xffffffff;
	76	carry = n >> 32;
	77	}
	78	}
	79	return *this;
	80	}
	81
	82	template <unsigned int BITS>
	83	base_uint<BITS>& base_uint<BITS>::operator/=(const base_uint& b)
84	{
85	base_uint<BITS> div = b; // make a copy, so we can shift.
86	base_uint<BITS> num = *this; // make a copy, so we can subtract.
87	*this = 0; // the quotient.
88	int num_bits = num.bits();
89	int div_bits = div.bits();
90	if (div_bits == 0)
91	throw uint_error("Division by zero");
92	if (div_bits > num_bits) // the result is certainly 0.
93	return *this;
94	int shift = num_bits - div_bits;
95	div <<= shift; // shift so that div and num align.
96	while (shift >= 0) {
97	if (num >= div) {
98	num -= div;
99	pn[shift / 32] \|= (1 << (shift & 31)); // set a bit of the result.
100	}
101	div >>= 1; // shift back.
102	shift--;
103	}
104	// num now contains the remainder of the division.
105	return *this;
106	}
107
108	template <unsigned int BITS>
109	int base_uint<BITS>::CompareTo(const base_uint<BITS>& b) const
110	{
111	for (int i = WIDTH - 1; i >= 0; i--) {
112	if (pn[i] < b.pn[i])
113	return -1;
114	if (pn[i] > b.pn[i])
115	return 1;
116	}
117	return 0;
118	}
119
120	template <unsigned int BITS>
121	bool base_uint<BITS>::EqualTo(uint64_t b) const
122	{
123	for (int i = WIDTH - 1; i >= 2; i--) {
124	if (pn[i])
125	return false;
126	}
127	if (pn[1] != (b >> 32))
128	return false;
129	if (pn[0] != (b & 0xfffffffful))
130	return false;
131	return true;
132	}
133
134	template <unsigned int BITS>
135	double base_uint<BITS>::getdouble() const
136	{
137	double ret = 0.0;
138	double fact = 1.0;
139	for (int i = 0; i < WIDTH; i++) {
140	ret += fact * pn[i];
141	fact *= 4294967296.0;
142	}
143	return ret;
144	}
145
146	template <unsigned int BITS>
147	std::string base_uint<BITS>::GetHex() const
148	{
6bd0dc2a	149	return ArithToUint256(*this).GetHex();
bfc60703 WL	150	}
	151
	152	template <unsigned int BITS>
	153	void base_uint<BITS>::SetHex(const char* psz)
	154	{
6bd0dc2a	155	*this = UintToArith256(uint256S(psz));
bfc60703 WL	156	}
	157
	158	template <unsigned int BITS>
	159	void base_uint<BITS>::SetHex(const std::string& str)
	160	{
	161	SetHex(str.c_str());
	162	}
	163
	164	template <unsigned int BITS>
	165	std::string base_uint<BITS>::ToString() const
	166	{
	167	return (GetHex());
	168	}
	169
	170	template <unsigned int BITS>
	171	unsigned int base_uint<BITS>::bits() const
	172	{
	173	for (int pos = WIDTH - 1; pos >= 0; pos--) {
	174	if (pn[pos]) {
	175	for (int bits = 31; bits > 0; bits--) {
	176	if (pn[pos] & 1 << bits)
	177	return 32 * pos + bits + 1;
	178	}
	179	return 32 * pos + 1;
	180	}
	181	}
	182	return 0;
	183	}
	184
bfc60703 WL	185	// Explicit instantiations for base_uint<256>
bfc60703 WL	186	template base_uint<256>::base_uint(const std::string&);
bfc60703 WL	187	template base_uint<256>& base_uint<256>::operator<<=(unsigned int);
	188	template base_uint<256>& base_uint<256>::operator>>=(unsigned int);
	189	template base_uint<256>& base_uint<256>::operator*=(uint32_t b32);
	190	template base_uint<256>& base_uint<256>::operator*=(const base_uint<256>& b);
	191	template base_uint<256>& base_uint<256>::operator/=(const base_uint<256>& b);
	192	template int base_uint<256>::CompareTo(const base_uint<256>&) const;
	193	template bool base_uint<256>::EqualTo(uint64_t) const;
	194	template double base_uint<256>::getdouble() const;
	195	template std::string base_uint<256>::GetHex() const;
	196	template std::string base_uint<256>::ToString() const;
	197	template void base_uint<256>::SetHex(const char*);
	198	template void base_uint<256>::SetHex(const std::string&);
	199	template unsigned int base_uint<256>::bits() const;
	200
	201	// This implementation directly uses shifts instead of going
	202	// through an intermediate MPI representation.
	203	arith_uint256& arith_uint256::SetCompact(uint32_t nCompact, bool* pfNegative, bool* pfOverflow)
	204	{
	205	int nSize = nCompact >> 24;
	206	uint32_t nWord = nCompact & 0x007fffff;
	207	if (nSize <= 3) {
	208	nWord >>= 8 * (3 - nSize);
	209	*this = nWord;
	210	} else {
	211	*this = nWord;
	212	this <<= 8 (nSize - 3);
	213	}
	214	if (pfNegative)
	215	*pfNegative = nWord != 0 && (nCompact & 0x00800000) != 0;
	216	if (pfOverflow)
	217	*pfOverflow = nWord != 0 && ((nSize > 34) \|\|
	218	(nWord > 0xff && nSize > 33) \|\|
	219	(nWord > 0xffff && nSize > 32));
	220	return *this;
	221	}
	222
	223	uint32_t arith_uint256::GetCompact(bool fNegative) const
	224	{
	225	int nSize = (bits() + 7) / 8;
	226	uint32_t nCompact = 0;
	227	if (nSize <= 3) {
	228	nCompact = GetLow64() << 8 * (3 - nSize);
	229	} else {
	230	arith_uint256 bn = this >> 8 (nSize - 3);
	231	nCompact = bn.GetLow64();
	232	}
	233	// The 0x00800000 bit denotes the sign.
	234	// Thus, if it is already set, divide the mantissa by 256 and increase the exponent.
	235	if (nCompact & 0x00800000) {
	236	nCompact >>= 8;
	237	nSize++;
	238	}
	239	assert((nCompact & ~0x007fffff) == 0);
	240	assert(nSize < 256);
	241	nCompact \|= nSize << 24;
	242	nCompact \|= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0);
	243	return nCompact;
	244	}
	245
92cdb1aa WL	246	uint256 ArithToUint256(const arith_uint256 &a)
	247	{
	248	uint256 b;
	249	// TODO: needs bswap32 on big-endian
	250	memcpy(b.begin(), a.pn, a.size());
	251	return b;
	252	}
	253	arith_uint256 UintToArith256(const uint256 &a)
	254	{
	255	arith_uint256 b;
	256	// TODO: needs bswap32 on big-endian
	257	memcpy(b.pn, a.begin(), a.size());
	258	return b;
	259	}