/root/bitcoin/src/arith_uint256.h

Source (jump to first uncovered line)
// 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.

#ifndef BITCOIN_ARITH_UINT256_H
#define BITCOIN_ARITH_UINT256_H

#include <cstdint>
#include <cstring>
#include <limits>
#include <stdexcept>
#include <string>

class uint256;

class uint_error : public std::runtime_error {
public:
    explicit uint_error(const std::string& str) : std::runtime_error(str) {}
};

/** Template base class for unsigned big integers. */
template<unsigned int BITS>
class base_uint
{
protected:
    static_assert(BITS / 32 > 0 && BITS % 32 == 0, "Template parameter BITS must be a positive multiple of 32.");
    static constexpr int WIDTH = BITS / 32;
    /** Big integer represented with 32-bit digits, least-significant first. */
    uint32_t pn[WIDTH];
public:

    base_uint()
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] = 0;
    }

    base_uint(const base_uint& b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] = b.pn[i];
    }

    base_uint& operator=(const base_uint& b)
    {
        if (this != &b) {
            for (int i = 0; i < WIDTH; i++)
                pn[i] = b.pn[i];
        }
        return *this;
    }

    base_uint(uint64_t b)
    {
        pn[0] = (unsigned int)b;
        pn[1] = (unsigned int)(b >> 32);
        for (int i = 2; i < WIDTH; i++)
            pn[i] = 0;
    }

    base_uint operator~() const
    {
        base_uint ret;
        for (int i = 0; i < WIDTH; i++)
            ret.pn[i] = ~pn[i];
        return ret;
    }

    base_uint operator-() const
    {
        base_uint ret;
        for (int i = 0; i < WIDTH; i++)
            ret.pn[i] = ~pn[i];
        ++ret;
        return ret;
    }

    double getdouble() const;

    base_uint& operator=(uint64_t b)
    {
        pn[0] = (unsigned int)b;
        pn[1] = (unsigned int)(b >> 32);
        for (int i = 2; i < WIDTH; i++)
            pn[i] = 0;
        return *this;
    }

    base_uint& operator^=(const base_uint& b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] ^= b.pn[i];
        return *this;
    }

    base_uint& operator&=(const base_uint& b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] &= b.pn[i];
        return *this;
    }

    base_uint& operator|=(const base_uint& b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] |= b.pn[i];
        return *this;
    }

    base_uint& operator^=(uint64_t b)
    {
        pn[0] ^= (unsigned int)b;
        pn[1] ^= (unsigned int)(b >> 32);
        return *this;
    }

    base_uint& operator|=(uint64_t b)
    {
        pn[0] |= (unsigned int)b;
        pn[1] |= (unsigned int)(b >> 32);
        return *this;
    }

    base_uint& operator<<=(unsigned int shift);
    base_uint& operator>>=(unsigned int shift);

    base_uint& operator+=(const base_uint& b)
    {
        uint64_t carry = 0;
        for (int i = 0; i < WIDTH; i++)
        {
            uint64_t n = carry + pn[i] + b.pn[i];
            pn[i] = n & 0xffffffff;
            carry = n >> 32;
        }
        return *this;
    }

    base_uint& operator-=(const base_uint& b)
    {
        *this += -b;
        return *this;
    }

    base_uint& operator+=(uint64_t b64)
    {
        base_uint b;
        b = b64;
        *this += b;
        return *this;
    }

    base_uint& operator-=(uint64_t b64)
    {
        base_uint b;
        b = b64;
        *this += -b;
        return *this;
    }

    base_uint& operator*=(uint32_t b32);
    base_uint& operator*=(const base_uint& b);
    base_uint& operator/=(const base_uint& b);

    base_uint& operator++()
    {
        // prefix operator
        int i = 0;
        while (i < WIDTH && ++pn[i] == 0)
            i++;
        return *this;
    }

    base_uint operator++(int)
    {
        // postfix operator
        const base_uint ret = *this;
        ++(*this);
        return ret;
    }

    base_uint& operator--()
    {
        // prefix operator
        int i = 0;
        while (i < WIDTH && --pn[i] == std::numeric_limits<uint32_t>::max())
            i++;
        return *this;
    }

    base_uint operator--(int)
    {
        // postfix operator
        const base_uint ret = *this;
        --(*this);
        return ret;
    }

    /** Numeric ordering (unlike \ref base_blob::Compare) */
    int CompareTo(const base_uint& b) const;
    bool EqualTo(uint64_t b) const;

    friend inline base_uint operator+(const base_uint& a, const base_uint& b) { return base_uint(a) += b; }
    friend inline base_uint operator-(const base_uint& a, const base_uint& b) { return base_uint(a) -= b; }
    friend inline base_uint operator*(const base_uint& a, const base_uint& b) { return base_uint(a) *= b; }
    friend inline base_uint operator/(const base_uint& a, const base_uint& b) { return base_uint(a) /= b; }
    friend inline base_uint operator|(const base_uint& a, const base_uint& b) { return base_uint(a) |= b; }
    friend inline base_uint operator&(const base_uint& a, const base_uint& b) { return base_uint(a) &= b; }
    friend inline base_uint operator^(const base_uint& a, const base_uint& b) { return base_uint(a) ^= b; }
    friend inline base_uint operator>>(const base_uint& a, int shift) { return base_uint(a) >>= shift; }
    friend inline base_uint operator<<(const base_uint& a, int shift) { return base_uint(a) <<= shift; }
    friend inline base_uint operator*(const base_uint& a, uint32_t b) { return base_uint(a) *= b; }
    friend inline bool operator==(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) == 0; }
    friend inline bool operator!=(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) != 0; }
    friend inline bool operator>(const base_uint& a, const base_uint& b) { return a.CompareTo(b) > 0; }
    friend inline bool operator<(const base_uint& a, const base_uint& b) { return a.CompareTo(b) < 0; }
    friend inline bool operator>=(const base_uint& a, const base_uint& b) { return a.CompareTo(b) >= 0; }
    friend inline bool operator<=(const base_uint& a, const base_uint& b) { return a.CompareTo(b) <= 0; }
    friend inline bool operator==(const base_uint& a, uint64_t b) { return a.EqualTo(b); }
    friend inline bool operator!=(const base_uint& a, uint64_t b) { return !a.EqualTo(b); }

    /** Hex encoding of the number (with the most significant digits first). */
    std::string GetHex() const;
    std::string ToString() const;

    unsigned int size() const
    {
        return sizeof(pn);
    }

    /**
     * Returns the position of the highest bit set plus one, or zero if the
     * value is zero.
     */
    unsigned int bits() const;

    uint64_t GetLow64() const
    {
        static_assert(WIDTH >= 2, "Assertion WIDTH >= 2 failed (WIDTH = BITS / 32). BITS is a template parameter.");
        return pn[0] | (uint64_t)pn[1] << 32;
    }
};

/** 256-bit unsigned big integer. */
class arith_uint256 : public base_uint<256> {
public:
    arith_uint256() = default;
    arith_uint256(const base_uint<256>& b) : base_uint<256>(b) {}
    arith_uint256(uint64_t b) : base_uint<256>(b) {}

    /**
     * The "compact" format is a representation of a whole
     * number N using an unsigned 32bit number similar to a
     * floating point format.
     * The most significant 8 bits are the unsigned exponent of base 256.
     * This exponent can be thought of as "number of bytes of N".
     * The lower 23 bits are the mantissa.
     * Bit number 24 (0x800000) represents the sign of N.
     * N = (-1^sign) * mantissa * 256^(exponent-3)
     *
     * Satoshi's original implementation used BN_bn2mpi() and BN_mpi2bn().
     * MPI uses the most significant bit of the first byte as sign.
     * Thus 0x1234560000 is compact (0x05123456)
     * and  0xc0de000000 is compact (0x0600c0de)
     *
     * Bitcoin only uses this "compact" format for encoding difficulty
     * targets, which are unsigned 256bit quantities.  Thus, all the
     * complexities of the sign bit and using base 256 are probably an
     * implementation accident.
     */
    arith_uint256& SetCompact(uint32_t nCompact, bool *pfNegative = nullptr, bool *pfOverflow = nullptr);
    uint32_t GetCompact(bool fNegative = false) const;

    friend uint256 ArithToUint256(const arith_uint256 &);
    friend arith_uint256 UintToArith256(const uint256 &);
};

uint256 ArithToUint256(const arith_uint256 &);
arith_uint256 UintToArith256(const uint256 &);

extern template class base_uint<256>;

#endif // BITCOIN_ARITH_UINT256_H

Coverage Report

Created: 2025-03-18 19:34

Line	Count	Source (jump to first uncovered line)
1		// Copyright (c) 2009-2010 Satoshi Nakamoto
2		// Copyright (c) 2009-2022 The Bitcoin Core 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		#ifndef BITCOIN_ARITH_UINT256_H
7		#define BITCOIN_ARITH_UINT256_H
8
9		#include <cstdint>
10		#include <cstring>
11		#include <limits>
12		#include <stdexcept>
13		#include <string>
14
15		class uint256;
16
17		class uint_error : public std::runtime_error {
18		public:
19	0	explicit uint_error(const std::string& str) : std::runtime_error(str) {}
20		};
21
22		/** Template base class for unsigned big integers. */
23		template<unsigned int BITS>
24		class base_uint
25		{
26		protected:
27		static_assert(BITS / 32 > 0 && BITS % 32 == 0, "Template parameter BITS must be a positive multiple of 32.");
28		static constexpr int WIDTH = BITS / 32;
29		/** Big integer represented with 32-bit digits, least-significant first. */
30		uint32_t pn[WIDTH];
31		public:
32
33		base_uint()
34	0	{
35	0	for (int i = 0; i < WIDTH; i++) Branch (35:25): [True: 0, False: 0] Branch (35:25): [True: 0, False: 0]
36	0	pn[i] = 0;
37	0	} Unexecuted instantiation: base_uint<256u>::base_uint() Unexecuted instantiation: base_uint<6144u>::base_uint()
38
39		base_uint(const base_uint& b)
40	0	{
41	0	for (int i = 0; i < WIDTH; i++) Branch (41:25): [True: 0, False: 0] Branch (41:25): [True: 0, False: 0]
42	0	pn[i] = b.pn[i];
43	0	} Unexecuted instantiation: base_uint<256u>::base_uint(base_uint<256u> const&) Unexecuted instantiation: base_uint<6144u>::base_uint(base_uint<6144u> const&)
44
45		base_uint& operator=(const base_uint& b)
46	0	{
47	0	if (this != &b) { Branch (47:13): [True: 0, False: 0] Branch (47:13): [True: 0, False: 0]
48	0	for (int i = 0; i < WIDTH; i++) Branch (48:29): [True: 0, False: 0] Branch (48:29): [True: 0, False: 0]
49	0	pn[i] = b.pn[i];
50	0	}
51	0	return *this;
52	0	} Unexecuted instantiation: base_uint<256u>::operator=(base_uint<256u> const&) Unexecuted instantiation: base_uint<6144u>::operator=(base_uint<6144u> const&)
53
54		base_uint(uint64_t b)
55	0	{
56	0	pn[0] = (unsigned int)b;
57	0	pn[1] = (unsigned int)(b >> 32);
58	0	for (int i = 2; i < WIDTH; i++) Branch (58:25): [True: 0, False: 0] Branch (58:25): [True: 0, False: 0]
59	0	pn[i] = 0;
60	0	} Unexecuted instantiation: base_uint<6144u>::base_uint(unsigned long) Unexecuted instantiation: base_uint<256u>::base_uint(unsigned long)
61
62		base_uint operator~() const
63	0	{
64	0	base_uint ret;
65	0	for (int i = 0; i < WIDTH; i++) Branch (65:25): [True: 0, False: 0]
66	0	ret.pn[i] = ~pn[i];
67	0	return ret;
68	0	}
69
70		base_uint operator-() const
71	0	{
72	0	base_uint ret;
73	0	for (int i = 0; i < WIDTH; i++) Branch (73:25): [True: 0, False: 0] Branch (73:25): [True: 0, False: 0]
74	0	ret.pn[i] = ~pn[i];
75	0	++ret;
76	0	return ret;
77	0	} Unexecuted instantiation: base_uint<256u>::operator-() const Unexecuted instantiation: base_uint<6144u>::operator-() const
78
79		double getdouble() const;
80
81		base_uint& operator=(uint64_t b)
82	0	{
83	0	pn[0] = (unsigned int)b;
84	0	pn[1] = (unsigned int)(b >> 32);
85	0	for (int i = 2; i < WIDTH; i++) Branch (85:25): [True: 0, False: 0] Branch (85:25): [True: 0, False: 0]
86	0	pn[i] = 0;
87	0	return *this;
88	0	} Unexecuted instantiation: base_uint<256u>::operator=(unsigned long) Unexecuted instantiation: base_uint<6144u>::operator=(unsigned long)
89
90		base_uint& operator^=(const base_uint& b)
91	0	{
92	0	for (int i = 0; i < WIDTH; i++) Branch (92:25): [True: 0, False: 0]
93	0	pn[i] ^= b.pn[i];
94	0	return *this;
95	0	}
96
97		base_uint& operator&=(const base_uint& b)
98	0	{
99	0	for (int i = 0; i < WIDTH; i++) Branch (99:25): [True: 0, False: 0]
100	0	pn[i] &= b.pn[i];
101	0	return *this;
102	0	}
103
104		base_uint& operator\|=(const base_uint& b)
105	0	{
106	0	for (int i = 0; i < WIDTH; i++) Branch (106:25): [True: 0, False: 0]
107	0	pn[i] \|= b.pn[i];
108	0	return *this;
109	0	}
110
111		base_uint& operator^=(uint64_t b)
112	0	{
113	0	pn[0] ^= (unsigned int)b;
114	0	pn[1] ^= (unsigned int)(b >> 32);
115	0	return *this;
116	0	}
117
118		base_uint& operator\|=(uint64_t b)
119	0	{
120	0	pn[0] \|= (unsigned int)b;
121	0	pn[1] \|= (unsigned int)(b >> 32);
122	0	return *this;
123	0	}
124
125		base_uint& operator<<=(unsigned int shift);
126		base_uint& operator>>=(unsigned int shift);
127
128		base_uint& operator+=(const base_uint& b)
129	0	{
130	0	uint64_t carry = 0;
131	0	for (int i = 0; i < WIDTH; i++) Branch (131:25): [True: 0, False: 0] Branch (131:25): [True: 0, False: 0]
132	0	{
133	0	uint64_t n = carry + pn[i] + b.pn[i];
134	0	pn[i] = n & 0xffffffff;
135	0	carry = n >> 32;
136	0	}
137	0	return *this;
138	0	} Unexecuted instantiation: base_uint<256u>::operator+=(base_uint<256u> const&) Unexecuted instantiation: base_uint<6144u>::operator+=(base_uint<6144u> const&)
139
140		base_uint& operator-=(const base_uint& b)
141	0	{
142	0	*this += -b;
143	0	return *this;
144	0	} Unexecuted instantiation: base_uint<256u>::operator-=(base_uint<256u> const&) Unexecuted instantiation: base_uint<6144u>::operator-=(base_uint<6144u> const&)
145
146		base_uint& operator+=(uint64_t b64)
147	0	{
148	0	base_uint b;
149	0	b = b64;
150	0	*this += b;
151	0	return *this;
152	0	}
153
154		base_uint& operator-=(uint64_t b64)
155	0	{
156	0	base_uint b;
157	0	b = b64;
158	0	*this += -b;
159	0	return *this;
160	0	}
161
162		base_uint& operator*=(uint32_t b32);
163		base_uint& operator*=(const base_uint& b);
164		base_uint& operator/=(const base_uint& b);
165
166		base_uint& operator++()
167	0	{
168		// prefix operator
169	0	int i = 0;
170	0	while (i < WIDTH && ++pn[i] == 0) Branch (170:16): [True: 0, False: 0] Branch (170:29): [True: 0, False: 0] Branch (170:16): [True: 0, False: 0] Branch (170:29): [True: 0, False: 0]
171	0	i++;
172	0	return *this;
173	0	} Unexecuted instantiation: base_uint<256u>::operator++() Unexecuted instantiation: base_uint<6144u>::operator++()
174
175		base_uint operator++(int)
176	0	{
177		// postfix operator
178	0	const base_uint ret = *this;
179	0	++(*this);
180	0	return ret;
181	0	}
182
183		base_uint& operator--()
184	0	{
185		// prefix operator
186	0	int i = 0;
187	0	while (i < WIDTH && --pn[i] == std::numeric_limits<uint32_t>::max()) Branch (187:16): [True: 0, False: 0] Branch (187:29): [True: 0, False: 0]
188	0	i++;
189	0	return *this;
190	0	}
191
192		base_uint operator--(int)
193	0	{
194		// postfix operator
195	0	const base_uint ret = *this;
196	0	--(*this);
197	0	return ret;
198	0	}
199
200		/** Numeric ordering (unlike \ref base_blob::Compare) */
201		int CompareTo(const base_uint& b) const;
202		bool EqualTo(uint64_t b) const;
203
204	0	friend inline base_uint operator+(const base_uint& a, const base_uint& b) { return base_uint(a) += b; }
205	0	friend inline base_uint operator-(const base_uint& a, const base_uint& b) { return base_uint(a) -= b; }
206	0	friend inline base_uint operator(const base_uint& a, const base_uint& b) { return base_uint(a) = b; }
207	0	friend inline base_uint operator/(const base_uint& a, const base_uint& b) { return base_uint(a) /= b; }
208		friend inline base_uint operator\|(const base_uint& a, const base_uint& b) { return base_uint(a) \|= b; }
209		friend inline base_uint operator&(const base_uint& a, const base_uint& b) { return base_uint(a) &= b; }
210		friend inline base_uint operator^(const base_uint& a, const base_uint& b) { return base_uint(a) ^= b; }
211	0	friend inline base_uint operator>>(const base_uint& a, int shift) { return base_uint(a) >>= shift; }
212		friend inline base_uint operator<<(const base_uint& a, int shift) { return base_uint(a) <<= shift; }
213	0	friend inline base_uint operator(const base_uint& a, uint32_t b) { return base_uint(a) = b; }
214	0	friend inline bool operator==(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) == 0; }
215	0	friend inline bool operator!=(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) != 0; }
216	0	friend inline bool operator>(const base_uint& a, const base_uint& b) { return a.CompareTo(b) > 0; }
217	0	friend inline bool operator<(const base_uint& a, const base_uint& b) { return a.CompareTo(b) < 0; }
218	0	friend inline bool operator>=(const base_uint& a, const base_uint& b) { return a.CompareTo(b) >= 0; } Unexecuted instantiation: operator>=(base_uint<256u> const&, base_uint<256u> const&) Unexecuted instantiation: operator>=(base_uint<6144u> const&, base_uint<6144u> const&)
219	0	friend inline bool operator<=(const base_uint& a, const base_uint& b) { return a.CompareTo(b) <= 0; }
220	0	friend inline bool operator==(const base_uint& a, uint64_t b) { return a.EqualTo(b); }
221		friend inline bool operator!=(const base_uint& a, uint64_t b) { return !a.EqualTo(b); }
222
223		/** Hex encoding of the number (with the most significant digits first). */
224		std::string GetHex() const;
225		std::string ToString() const;
226
227		unsigned int size() const
228	0	{
229	0	return sizeof(pn);
230	0	}
231
232		/**
233		* Returns the position of the highest bit set plus one, or zero if the
234		* value is zero.
235		*/
236		unsigned int bits() const;
237
238		uint64_t GetLow64() const
239	0	{
240	0	static_assert(WIDTH >= 2, "Assertion WIDTH >= 2 failed (WIDTH = BITS / 32). BITS is a template parameter.");
241	0	return pn[0] \| (uint64_t)pn[1] << 32;
242	0	}
243		};
244
245		/** 256-bit unsigned big integer. */
246		class arith_uint256 : public base_uint<256> {
247		public:
248	0	arith_uint256() = default;
249	0	arith_uint256(const base_uint<256>& b) : base_uint<256>(b) {}
250	0	arith_uint256(uint64_t b) : base_uint<256>(b) {}
251
252		/**
253		* The "compact" format is a representation of a whole
254		* number N using an unsigned 32bit number similar to a
255		* floating point format.
256		* The most significant 8 bits are the unsigned exponent of base 256.
257		* This exponent can be thought of as "number of bytes of N".
258		* The lower 23 bits are the mantissa.
259		* Bit number 24 (0x800000) represents the sign of N.
260		* N = (-1^sign) * mantissa * 256^(exponent-3)
261		*
262		* Satoshi's original implementation used BN_bn2mpi() and BN_mpi2bn().
263		* MPI uses the most significant bit of the first byte as sign.
264		* Thus 0x1234560000 is compact (0x05123456)
265		* and 0xc0de000000 is compact (0x0600c0de)
266		*
267		* Bitcoin only uses this "compact" format for encoding difficulty
268		* targets, which are unsigned 256bit quantities. Thus, all the
269		* complexities of the sign bit and using base 256 are probably an
270		* implementation accident.
271		*/
272		arith_uint256& SetCompact(uint32_t nCompact, bool pfNegative = nullptr, bool pfOverflow = nullptr);
273		uint32_t GetCompact(bool fNegative = false) const;
274
275		friend uint256 ArithToUint256(const arith_uint256 &);
276		friend arith_uint256 UintToArith256(const uint256 &);
277		};
278
279		uint256 ArithToUint256(const arith_uint256 &);
280		arith_uint256 UintToArith256(const uint256 &);
281
282		extern template class base_uint<256>;
283
284		#endif // BITCOIN_ARITH_UINT256_H