16511306696

Committed 25 Jul 2025 01:07AM UTC coverage: 90.698% (+0.005%) from 90.693%

Build # 16511306696

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Merge pull request #5017 from randombit/jack/mp-cleanup

Clean up low level mp interfaces

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91.18

/src/lib/math/bigint/big_ops3.cpp

/*
* BigInt Binary Operators
* (C) 1999-2007,2018 Jack Lloyd
*     2016 Matthias Gierlings
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/bigint.h>

#include <botan/internal/bit_ops.h>
#include <botan/internal/divide.h>
#include <botan/internal/mp_core.h>
#include <algorithm>

namespace Botan {

//static
BigInt BigInt::add2(const BigInt& x, const word y[], size_t y_size, BigInt::Sign y_sign) {
   const size_t x_sw = x.sig_words();

   BigInt z = BigInt::with_capacity(std::max(x_sw, y_size) + 1);

   if(x.sign() == y_sign) {
      word carry = bigint_add3(z.mutable_data(), x._data(), x_sw, y, y_size);
      z.mutable_data()[std::max(x_sw, y_size)] += carry;
      z.set_sign(x.sign());
   } else {
      const int32_t relative_size = bigint_cmp(x.data(), x_sw, y, y_size);

      if(relative_size < 0) {
         // x < y so z = abs(y - x)
         // NOLINTNEXTLINE(*-suspicious-call-argument) intentionally swapping x and y here
         bigint_sub3(z.mutable_data(), y, y_size, x.data(), x_sw);
         z.set_sign(y_sign);
      } else if(relative_size == 0) {
         // Positive zero (nothing to do in this case)
      } else {
         /*
         * We know at this point that x >= y so if y_size is larger than
         * x_sw, we are guaranteed they are just leading zeros which can
         * be ignored
         */
         y_size = std::min(x_sw, y_size);
         bigint_sub3(z.mutable_data(), x.data(), x_sw, y, y_size);
         z.set_sign(x.sign());
      }
   }

   return z;
}

/*
* Multiplication Operator
*/
BigInt operator*(const BigInt& x, const BigInt& y) {
   const size_t x_sw = x.sig_words();
   const size_t y_sw = y.sig_words();

   BigInt z = BigInt::with_capacity(x.size() + y.size());

   if(x_sw == 1 && y_sw > 0) {
      bigint_linmul3(z.mutable_data(), y._data(), y_sw, x.word_at(0));
   } else if(y_sw == 1 && x_sw > 0) {
      bigint_linmul3(z.mutable_data(), x._data(), x_sw, y.word_at(0));
   } else if(x_sw > 0 && y_sw > 0) {
      secure_vector<word> workspace(z.size());

      bigint_mul(z.mutable_data(),
                 z.size(),
                 x._data(),
                 x.size(),
                 x_sw,
                 y._data(),
                 y.size(),
                 y_sw,
                 workspace.data(),
                 workspace.size());
   }

   z.cond_flip_sign(x_sw > 0 && y_sw > 0 && x.sign() != y.sign());

   return z;
}

/*
* Multiplication Operator
*/
BigInt operator*(const BigInt& x, word y) {
   const size_t x_sw = x.sig_words();

   BigInt z = BigInt::with_capacity(x_sw + 1);

   if(x_sw > 0 && y > 0) {
      bigint_linmul3(z.mutable_data(), x._data(), x_sw, y);
      z.set_sign(x.sign());
   }

   return z;
}

/*
* Division Operator
*/
BigInt operator/(const BigInt& x, const BigInt& y) {
   if(y.sig_words() == 1) {
      return x / y.word_at(0);
   }

   BigInt q;
   BigInt r;
   vartime_divide(x, y, q, r);
   return q;
}

/*
* Division Operator
*/
BigInt operator/(const BigInt& x, word y) {
   if(y == 0) {
      throw Invalid_Argument("BigInt::operator/ divide by zero");
   }

   BigInt q;
   word r = 0;
   ct_divide_word(x, y, q, r);
   return q;
}

/*
* Modulo Operator
*/
BigInt operator%(const BigInt& n, const BigInt& mod) {
   if(mod.is_zero()) {
      throw Invalid_Argument("BigInt::operator% divide by zero");
   }
   if(mod.is_negative()) {
      throw Invalid_Argument("BigInt::operator% modulus must be > 0");
   }
   if(n.is_positive() && mod.is_positive() && n < mod) {
      return n;
   }

   if(mod.sig_words() == 1) {
      return BigInt::from_word(n % mod.word_at(0));
   }

   BigInt q;
   BigInt r;
   vartime_divide(n, mod, q, r);
   return r;
}

/*
* Modulo Operator
*/
word operator%(const BigInt& n, word mod) {
   if(mod == 0) {
      throw Invalid_Argument("BigInt::operator% divide by zero");
   }

   if(mod == 1) {
      return 0;
   }

   word remainder = 0;

   if(is_power_of_2(mod)) {
      remainder = (n.word_at(0) & (mod - 1));
   } else {
      const size_t sw = n.sig_words();
      for(size_t i = sw; i > 0; --i) {
         remainder = bigint_modop_vartime(remainder, n.word_at(i - 1), mod);
      }
   }

   if(remainder != 0 && n.sign() == BigInt::Negative) {
      return mod - remainder;
   }
   return remainder;
}

/*
* Left Shift Operator
*/
BigInt operator<<(const BigInt& x, size_t shift) {
   const size_t x_sw = x.sig_words();

   const size_t new_size = x_sw + (shift + WordInfo<word>::bits - 1) / WordInfo<word>::bits;
   BigInt y = BigInt::with_capacity(new_size);
   bigint_shl2(y.mutable_data(), x._data(), x_sw, shift);
   y.set_sign(x.sign());
   return y;
}

/*
* Right Shift Operator
*/
BigInt operator>>(const BigInt& x, size_t shift) {
   const size_t shift_words = shift / WordInfo<word>::bits;
   const size_t x_sw = x.sig_words();

   if(shift_words >= x_sw) {
      return BigInt::zero();
   }

   BigInt y = BigInt::with_capacity(x_sw - shift_words);
   bigint_shr2(y.mutable_data(), x._data(), x_sw, shift);

   if(x.is_negative() && y.is_zero()) {
      y.set_sign(BigInt::Positive);
   } else {
      y.set_sign(x.sign());
   }

   return y;
}

}  // namespace Botan

1	/*
2	* BigInt Binary Operators
3	* (C) 1999-2007,2018 Jack Lloyd
4	* 2016 Matthias Gierlings
5	*
6	* Botan is released under the Simplified BSD License (see license.txt)
7	*/
8
9	#include <botan/bigint.h>
10
11	#include <botan/internal/bit_ops.h>
12	#include <botan/internal/divide.h>
13	#include <botan/internal/mp_core.h>
14	#include <algorithm>
15
16	namespace Botan {
17
18	//static
19	BigInt BigInt::add2(const BigInt& x, const word y[], size_t y_size, BigInt::Sign y_sign) {	4,225,856✔
20	const size_t x_sw = x.sig_words();	4,225,856✔
21
22	BigInt z = BigInt::with_capacity(std::max(x_sw, y_size) + 1);	4,404,780✔
23
24	if(x.sign() == y_sign) {	4,225,856✔
25	word carry = bigint_add3(z.mutable_data(), x._data(), x_sw, y, y_size);	3,645,235✔
26	z.mutable_data()[std::max(x_sw, y_size)] += carry;	3,645,235✔
27	z.set_sign(x.sign());	3,645,235✔
28	} else {
29	const int32_t relative_size = bigint_cmp(x.data(), x_sw, y, y_size);	580,621✔
30
31	if(relative_size < 0) {	580,621✔
32	// x < y so z = abs(y - x)
33	// NOLINTNEXTLINE(*-suspicious-call-argument) intentionally swapping x and y here
34	bigint_sub3(z.mutable_data(), y, y_size, x.data(), x_sw);	7,321✔
35	z.set_sign(y_sign);	7,321✔
36	} else if(relative_size == 0) {	573,300✔
37	// Positive zero (nothing to do in this case)
38	} else {
39	/*
40	* We know at this point that x >= y so if y_size is larger than
41	* x_sw, we are guaranteed they are just leading zeros which can
42	* be ignored
43	*/
44	y_size = std::min(x_sw, y_size);	573,180✔
45	bigint_sub3(z.mutable_data(), x.data(), x_sw, y, y_size);	573,180✔
46	z.set_sign(x.sign());	573,180✔
47	}
48	}
49
50	return z;	4,225,856✔
51	}	×
52
53	/*
54	* Multiplication Operator
55	*/
56	BigInt operator*(const BigInt& x, const BigInt& y) {	46,838✔
57	const size_t x_sw = x.sig_words();	46,838✔
58	const size_t y_sw = y.sig_words();	46,838✔
59
60	BigInt z = BigInt::with_capacity(x.size() + y.size());	46,838✔
61
62	if(x_sw == 1 && y_sw > 0) {	46,838✔
63	bigint_linmul3(z.mutable_data(), y._data(), y_sw, x.word_at(0));	47,764✔
64	} else if(y_sw == 1 && x_sw > 0) {	22,956✔
65	bigint_linmul3(z.mutable_data(), x._data(), x_sw, y.word_at(0));	7,686✔
66	} else if(x_sw > 0 && y_sw > 0) {	19,113✔
67	secure_vector<word> workspace(z.size());	18,314✔
68
69	bigint_mul(z.mutable_data(),	18,314✔
70	z.size(),
71	x._data(),
72	x.size(),
73	x_sw,
74	y._data(),
75	y.size(),
76	y_sw,
77	workspace.data(),
78	workspace.size());
79	}	18,314✔
80
81	z.cond_flip_sign(x_sw > 0 && y_sw > 0 && x.sign() != y.sign());	93,306✔
82
83	return z;	46,838✔
84	}	×
85
86	/*
87	* Multiplication Operator
88	*/
89	BigInt operator*(const BigInt& x, word y) {	3,488,309✔
90	const size_t x_sw = x.sig_words();	3,488,309✔
91
92	BigInt z = BigInt::with_capacity(x_sw + 1);	3,488,309✔
93
94	if(x_sw > 0 && y > 0) {	3,488,309✔
95	bigint_linmul3(z.mutable_data(), x._data(), x_sw, y);	3,379,215✔
96	z.set_sign(x.sign());	3,379,215✔
97	}
98
99	return z;	3,488,309✔
100	}	×
101
102	/*
103	* Division Operator
104	*/
105	BigInt operator/(const BigInt& x, const BigInt& y) {	156,007✔
106	if(y.sig_words() == 1) {	158,449✔
107	return x / y.word_at(0);	110,878✔
108	}
109
110	BigInt q;	100,568✔
111	BigInt r;	100,568✔
112	vartime_divide(x, y, q, r);	100,568✔
113	return q;	100,568✔
114	}	100,568✔
115
116	/*
117	* Division Operator
118	*/
119	BigInt operator/(const BigInt& x, word y) {	381,005✔
120	if(y == 0) {	381,005✔
121	throw Invalid_Argument("BigInt::operator/ divide by zero");	×
122	}
123
124	BigInt q;	381,005✔
125	word r = 0;	381,005✔
126	ct_divide_word(x, y, q, r);	381,005✔
127	return q;	381,005✔
128	}	×
129
130	/*
131	* Modulo Operator
132	*/
133	BigInt operator%(const BigInt& n, const BigInt& mod) {	553,362✔
134	if(mod.is_zero()) {	553,472✔
135	throw Invalid_Argument("BigInt::operator% divide by zero");	×
136	}
137	if(mod.is_negative()) {	553,362✔
138	throw Invalid_Argument("BigInt::operator% modulus must be > 0");	×
139	}
140	if(n.is_positive() && mod.is_positive() && n < mod) {	1,075,536✔
141	return n;	172,497✔
142	}
143
144	if(mod.sig_words() == 1) {	380,865✔
145	return BigInt::from_word(n % mod.word_at(0));	363,976✔
146	}
147
148	BigInt q;	198,877✔
149	BigInt r;	198,877✔
150	vartime_divide(n, mod, q, r);	198,877✔
151	return r;	198,877✔
152	}	198,877✔
153
154	/*
155	* Modulo Operator
156	*/
157	word operator%(const BigInt& n, word mod) {	1,394,491✔
158	if(mod == 0) {	1,394,491✔
159	throw Invalid_Argument("BigInt::operator% divide by zero");	×
160	}
161
162	if(mod == 1) {	1,394,491✔
163	return 0;
164	}
165
166	word remainder = 0;	1,394,480✔
167
168	if(is_power_of_2(mod)) {	1,394,480✔
169	remainder = (n.word_at(0) & (mod - 1));	1,212,326✔
170	} else {
171	const size_t sw = n.sig_words();	788,317✔
172	for(size_t i = sw; i > 0; --i) {	8,083,026✔
173	remainder = bigint_modop_vartime(remainder, n.word_at(i - 1), mod);	14,589,418✔
174	}
175	}
176
177	if(remainder != 0 && n.sign() == BigInt::Negative) {	1,394,480✔
178	return mod - remainder;	29,959✔
179	}
180	return remainder;
181	}
182
183	/*
184	* Left Shift Operator
185	*/
186	BigInt operator<<(const BigInt& x, size_t shift) {	302,705✔
187	const size_t x_sw = x.sig_words();	302,705✔
188
189	const size_t new_size = x_sw + (shift + WordInfo<word>::bits - 1) / WordInfo<word>::bits;	302,705✔
190	BigInt y = BigInt::with_capacity(new_size);	302,705✔
191	bigint_shl2(y.mutable_data(), x._data(), x_sw, shift);	302,705✔
192	y.set_sign(x.sign());	302,705✔
193	return y;	302,705✔
194	}	×
195
196	/*
197	* Right Shift Operator
198	*/
199	BigInt operator>>(const BigInt& x, size_t shift) {	216,043✔
200	const size_t shift_words = shift / WordInfo<word>::bits;	216,043✔
201	const size_t x_sw = x.sig_words();	216,043✔
202
203	if(shift_words >= x_sw) {	216,043✔
204	return BigInt::zero();	2,062✔
205	}
206
207	BigInt y = BigInt::with_capacity(x_sw - shift_words);	213,981✔
208	bigint_shr2(y.mutable_data(), x._data(), x_sw, shift);	213,981✔
209
210	if(x.is_negative() && y.is_zero()) {	214,006✔
211	y.set_sign(BigInt::Positive);	3✔
212	} else {
213	y.set_sign(x.sign());	213,978✔
214	}
215
216	return y;	213,981✔
217	}	213,981✔
218
219	} // namespace Botan

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