5123321399

Committed 30 May 2023 04:06PM UTC coverage: 92.213% (+0.004%) from 92.209%

Build # 5123321399

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Pull #3558

github

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web-flow

Commit Message

Merge dd72f7389 into 057bcbc35

Pull Request Pull Request #3558: Add braces around all if/else statements

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

/*
* BigInt Base
* (C) 1999-2011,2012,2014,2019 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/bigint.h>

#include <botan/internal/bit_ops.h>
#include <botan/internal/ct_utils.h>
#include <botan/internal/loadstor.h>
#include <botan/internal/mp_core.h>
#include <botan/internal/rounding.h>

namespace Botan {

BigInt::BigInt(uint64_t n) {
#if BOTAN_MP_WORD_BITS == 64
   m_data.set_word_at(0, n);
#else
   m_data.set_word_at(1, static_cast<word>(n >> 32));
   m_data.set_word_at(0, static_cast<word>(n));
#endif
}

//static
BigInt BigInt::from_u64(uint64_t n) {
   BigInt bn;

#if BOTAN_MP_WORD_BITS == 64
   bn.set_word_at(0, n);
#else
   bn.set_word_at(1, static_cast<word>(n >> 32));
   bn.set_word_at(0, static_cast<word>(n));
#endif

   return bn;
}

//static
BigInt BigInt::from_word(word n) {
   BigInt bn;
   bn.set_word_at(0, n);
   return bn;
}

//static
BigInt BigInt::from_s32(int32_t n) {
   if(n >= 0) {
      return BigInt::from_u64(static_cast<uint64_t>(n));
   } else {
      return -BigInt::from_u64(static_cast<uint64_t>(-n));
   }
}

//static
BigInt BigInt::with_capacity(size_t size) {
   BigInt bn;
   bn.grow_to(size);
   return bn;
}

/*
* Construct a BigInt from a string
*/
BigInt::BigInt(std::string_view str) {
   Base base = Decimal;
   size_t markers = 0;
   bool negative = false;

   if(str.length() > 0 && str[0] == '-') {
      markers += 1;
      negative = true;
   }

   if(str.length() > markers + 2 && str[markers] == '0' && str[markers + 1] == 'x') {
      markers += 2;
      base = Hexadecimal;
   }

   *this = decode(cast_char_ptr_to_uint8(str.data()) + markers, str.length() - markers, base);

   if(negative) {
      set_sign(Negative);
   } else {
      set_sign(Positive);
   }
}

BigInt::BigInt(const uint8_t input[], size_t length) { binary_decode(input, length); }

/*
* Construct a BigInt from an encoded BigInt
*/
BigInt::BigInt(const uint8_t input[], size_t length, Base base) { *this = decode(input, length, base); }

//static
BigInt BigInt::from_bytes_with_max_bits(const uint8_t input[], size_t length, size_t max_bits) {
   const size_t input_bits = 8 * length;

   BigInt bn;
   bn.binary_decode(input, length);

   if(input_bits > max_bits) {
      const size_t bits_to_shift = input_bits - max_bits;

      bn >>= bits_to_shift;
   }

   return bn;
}

/*
* Construct a BigInt from an encoded BigInt
*/
BigInt::BigInt(RandomNumberGenerator& rng, size_t bits, bool set_high_bit) { randomize(rng, bits, set_high_bit); }

uint8_t BigInt::byte_at(size_t n) const {
   return get_byte_var(sizeof(word) - (n % sizeof(word)) - 1, word_at(n / sizeof(word)));
}

int32_t BigInt::cmp_word(word other) const {
   if(is_negative()) {
      return -1;  // other is positive ...
   }

   const size_t sw = this->sig_words();
   if(sw > 1) {
      return 1;  // must be larger since other is just one word ...
   }

   return bigint_cmp(this->data(), sw, &other, 1);
}

/*
* Comparison Function
*/
int32_t BigInt::cmp(const BigInt& other, bool check_signs) const {
   if(check_signs) {
      if(other.is_positive() && this->is_negative()) {
         return -1;
      }

      if(other.is_negative() && this->is_positive()) {
         return 1;
      }

      if(other.is_negative() && this->is_negative()) {
         return (-bigint_cmp(this->data(), this->size(), other.data(), other.size()));
      }
   }

   return bigint_cmp(this->data(), this->size(), other.data(), other.size());
}

bool BigInt::is_equal(const BigInt& other) const {
   if(this->sign() != other.sign()) {
      return false;
   }

   return bigint_ct_is_eq(this->data(), this->sig_words(), other.data(), other.sig_words()).is_set();
}

bool BigInt::is_less_than(const BigInt& other) const {
   if(this->is_negative() && other.is_positive()) {
      return true;
   }

   if(this->is_positive() && other.is_negative()) {
      return false;
   }

   if(other.is_negative() && this->is_negative()) {
      return bigint_ct_is_lt(other.data(), other.sig_words(), this->data(), this->sig_words()).is_set();
   }

   return bigint_ct_is_lt(this->data(), this->sig_words(), other.data(), other.sig_words()).is_set();
}

void BigInt::encode_words(word out[], size_t size) const {
   const size_t words = sig_words();

   if(words > size) {
      throw Encoding_Error("BigInt::encode_words value too large to encode");
   }

   clear_mem(out, size);
   copy_mem(out, data(), words);
}

size_t BigInt::Data::calc_sig_words() const {
   const size_t sz = m_reg.size();
   size_t sig = sz;

   word sub = 1;

   for(size_t i = 0; i != sz; ++i) {
      const word w = m_reg[sz - i - 1];
      sub &= ct_is_zero(w);
      sig -= sub;
   }

   /*
   * This depends on the data so is poisoned, but unpoison it here as
   * later conditionals are made on the size.
   */
   CT::unpoison(sig);

   return sig;
}

/*
* Return bits {offset...offset+length}
*/
uint32_t BigInt::get_substring(size_t offset, size_t length) const {
   if(length == 0 || length > 32) {
      throw Invalid_Argument("BigInt::get_substring invalid substring length");
   }

   const uint32_t mask = 0xFFFFFFFF >> (32 - length);

   const size_t word_offset = offset / BOTAN_MP_WORD_BITS;
   const size_t wshift = (offset % BOTAN_MP_WORD_BITS);

   /*
   * The substring is contained within one or at most two words. The
   * offset and length are not secret, so we can perform conditional
   * operations on those values.
   */
   const word w0 = word_at(word_offset);

   if(wshift == 0 || (offset + length) / BOTAN_MP_WORD_BITS == word_offset) {
      return static_cast<uint32_t>(w0 >> wshift) & mask;
   } else {
      const word w1 = word_at(word_offset + 1);
      return static_cast<uint32_t>((w0 >> wshift) | (w1 << (BOTAN_MP_WORD_BITS - wshift))) & mask;
   }
}

/*
* Convert this number to a uint32_t, if possible
*/
uint32_t BigInt::to_u32bit() const {
   if(is_negative()) {
      throw Encoding_Error("BigInt::to_u32bit: Number is negative");
   }
   if(bits() > 32) {
      throw Encoding_Error("BigInt::to_u32bit: Number is too big to convert");
   }

   uint32_t out = 0;
   for(size_t i = 0; i != 4; ++i) {
      out = (out << 8) | byte_at(3 - i);
   }
   return out;
}

/*
* Clear bit number n
*/
void BigInt::clear_bit(size_t n) {
   const size_t which = n / BOTAN_MP_WORD_BITS;

   if(which < size()) {
      const word mask = ~(static_cast<word>(1) << (n % BOTAN_MP_WORD_BITS));
      m_data.set_word_at(which, word_at(which) & mask);
   }
}

size_t BigInt::bytes() const { return round_up(bits(), 8) / 8; }

size_t BigInt::top_bits_free() const {
   const size_t words = sig_words();

   const word top_word = word_at(words - 1);
   const size_t bits_used = high_bit(top_word);
   CT::unpoison(bits_used);
   return BOTAN_MP_WORD_BITS - bits_used;
}

size_t BigInt::bits() const {
   const size_t words = sig_words();

   if(words == 0) {
      return 0;
   }

   const size_t full_words = (words - 1) * BOTAN_MP_WORD_BITS;
   const size_t top_bits = BOTAN_MP_WORD_BITS - top_bits_free();

   return full_words + top_bits;
}

/*
* Return the negation of this number
*/
BigInt BigInt::operator-() const {
   BigInt x = (*this);
   x.flip_sign();
   return x;
}

size_t BigInt::reduce_below(const BigInt& p, secure_vector<word>& ws) {
   if(p.is_negative() || this->is_negative()) {
      throw Invalid_Argument("BigInt::reduce_below both values must be positive");
   }

   const size_t p_words = p.sig_words();

   if(size() < p_words + 1) {
      grow_to(p_words + 1);
   }

   if(ws.size() < p_words + 1) {
      ws.resize(p_words + 1);
   }

   clear_mem(ws.data(), ws.size());

   size_t reductions = 0;

   for(;;) {
      word borrow = bigint_sub3(ws.data(), data(), p_words + 1, p.data(), p_words);
      if(borrow) {
         break;
      }

      ++reductions;
      swap_reg(ws);
   }

   return reductions;
}

void BigInt::ct_reduce_below(const BigInt& mod, secure_vector<word>& ws, size_t bound) {
   if(mod.is_negative() || this->is_negative()) {
      throw Invalid_Argument("BigInt::ct_reduce_below both values must be positive");
   }

   const size_t mod_words = mod.sig_words();

   grow_to(mod_words);

   const size_t sz = size();

   ws.resize(sz);

   clear_mem(ws.data(), sz);

   for(size_t i = 0; i != bound; ++i) {
      word borrow = bigint_sub3(ws.data(), data(), sz, mod.data(), mod_words);

      CT::Mask<word>::is_zero(borrow).select_n(mutable_data(), ws.data(), data(), sz);
   }
}

/*
* Return the absolute value of this number
*/
BigInt BigInt::abs() const {
   BigInt x = (*this);
   x.set_sign(Positive);
   return x;
}

void BigInt::binary_encode(uint8_t buf[]) const { this->binary_encode(buf, bytes()); }

/*
* Encode this number into bytes
*/
void BigInt::binary_encode(uint8_t output[], size_t len) const {
   const size_t full_words = len / sizeof(word);
   const size_t extra_bytes = len % sizeof(word);

   for(size_t i = 0; i != full_words; ++i) {
      const word w = word_at(i);
      store_be(w, output + (len - (i + 1) * sizeof(word)));
   }

   if(extra_bytes > 0) {
      const word w = word_at(full_words);

      for(size_t i = 0; i != extra_bytes; ++i) {
         output[extra_bytes - i - 1] = get_byte_var(sizeof(word) - i - 1, w);
      }
   }
}

/*
* Set this number to the value in buf
*/
void BigInt::binary_decode(const uint8_t buf[], size_t length) {
   clear();

   const size_t full_words = length / sizeof(word);
   const size_t extra_bytes = length % sizeof(word);

   secure_vector<word> reg((round_up(full_words + (extra_bytes > 0 ? 1 : 0), 8)));

   for(size_t i = 0; i != full_words; ++i) {
      reg[i] = load_be<word>(buf + length - sizeof(word) * (i + 1), 0);
   }

   if(extra_bytes > 0) {
      for(size_t i = 0; i != extra_bytes; ++i) {
         reg[full_words] = (reg[full_words] << 8) | buf[i];
      }
   }

   m_data.swap(reg);
}

void BigInt::ct_cond_add(bool predicate, const BigInt& value) {
   if(this->is_negative() || value.is_negative()) {
      throw Invalid_Argument("BigInt::ct_cond_add requires both values to be positive");
   }
   this->grow_to(1 + value.sig_words());

   bigint_cnd_add(static_cast<word>(predicate), this->mutable_data(), this->size(), value.data(), value.sig_words());
}

void BigInt::ct_cond_swap(bool predicate, BigInt& other) {
   const size_t max_words = std::max(size(), other.size());
   grow_to(max_words);
   other.grow_to(max_words);

   bigint_cnd_swap(predicate, this->mutable_data(), other.mutable_data(), max_words);
}

void BigInt::cond_flip_sign(bool predicate) {
   // This code is assuming Negative == 0, Positive == 1

   const auto mask = CT::Mask<uint8_t>::expand(predicate);

   const uint8_t current_sign = static_cast<uint8_t>(sign());

   const uint8_t new_sign = mask.select(current_sign ^ 1, current_sign);

   set_sign(static_cast<Sign>(new_sign));
}

void BigInt::ct_cond_assign(bool predicate, const BigInt& other) {
   const size_t t_words = size();
   const size_t o_words = other.size();

   if(o_words < t_words) {
      grow_to(o_words);
   }

   const size_t r_words = std::max(t_words, o_words);

   const auto mask = CT::Mask<word>::expand(predicate);

   for(size_t i = 0; i != r_words; ++i) {
      const word o_word = other.word_at(i);
      const word t_word = this->word_at(i);
      this->set_word_at(i, mask.select(o_word, t_word));
   }

   const bool different_sign = sign() != other.sign();
   cond_flip_sign(predicate && different_sign);
}

#if defined(BOTAN_HAS_VALGRIND)
void BigInt::const_time_poison() const { CT::poison(m_data.const_data(), m_data.size()); }

void BigInt::const_time_unpoison() const { CT::unpoison(m_data.const_data(), m_data.size()); }
#endif

}  // namespace Botan

1	/*
2	* BigInt Base
3	* (C) 1999-2011,2012,2014,2019 Jack Lloyd
4	*
5	* Botan is released under the Simplified BSD License (see license.txt)
6	*/
7
8	#include <botan/bigint.h>
9
10	#include <botan/internal/bit_ops.h>
11	#include <botan/internal/ct_utils.h>
12	#include <botan/internal/loadstor.h>
13	#include <botan/internal/mp_core.h>
14	#include <botan/internal/rounding.h>
15
16	namespace Botan {
17
18	BigInt::BigInt(uint64_t n) {	230,045✔
19	#if BOTAN_MP_WORD_BITS == 64
20	m_data.set_word_at(0, n);	230,045✔
21	#else
22	m_data.set_word_at(1, static_cast<word>(n >> 32));
23	m_data.set_word_at(0, static_cast<word>(n));
24	#endif
25	}	230,045✔
26
27	//static
28	BigInt BigInt::from_u64(uint64_t n) {	25,341✔
29	BigInt bn;	25,341✔
30
31	#if BOTAN_MP_WORD_BITS == 64
32	bn.set_word_at(0, n);	25,341✔
33	#else
34	bn.set_word_at(1, static_cast<word>(n >> 32));
35	bn.set_word_at(0, static_cast<word>(n));
36	#endif
37
38	return bn;	25,341✔
39	}	×
40
41	//static
42	BigInt BigInt::from_word(word n) {	571,775✔
43	BigInt bn;	571,775✔
44	bn.set_word_at(0, n);	571,775✔
45	return bn;	571,775✔
46	}	×
47
48	//static
49	BigInt BigInt::from_s32(int32_t n) {	2,667✔
50	if(n >= 0) {	2,667✔
51	return BigInt::from_u64(static_cast<uint64_t>(n));	2✔
52	} else {
53	return -BigInt::from_u64(static_cast<uint64_t>(-n));	5,330✔
54	}
55	}
56
57	//static
58	BigInt BigInt::with_capacity(size_t size) {	13,072,665✔
59	BigInt bn;	13,072,665✔
60	bn.grow_to(size);	13,072,665✔
61	return bn;	13,072,665✔
62	}	×
63
64	/*
65	* Construct a BigInt from a string
66	*/
67	BigInt::BigInt(std::string_view str) {	44,410✔
68	Base base = Decimal;	44,410✔
69	size_t markers = 0;	44,410✔
70	bool negative = false;	44,410✔
71
72	if(str.length() > 0 && str[0] == '-') {	44,410✔
73	markers += 1;
74	negative = true;
75	}
76
77	if(str.length() > markers + 2 && str[markers] == '0' && str[markers + 1] == 'x') {	44,410✔
78	markers += 2;
79	base = Hexadecimal;
80	}
81
82	*this = decode(cast_char_ptr_to_uint8(str.data()) + markers, str.length() - markers, base);	44,410✔
83
84	if(negative) {	44,410✔
85	set_sign(Negative);	445✔
86	} else {
87	set_sign(Positive);	43,965✔
88	}
89	}	44,410✔
90
91	BigInt::BigInt(const uint8_t input[], size_t length) { binary_decode(input, length); }	207,676✔
92
93	/*
94	* Construct a BigInt from an encoded BigInt
95	*/
96	BigInt::BigInt(const uint8_t input[], size_t length, Base base) { *this = decode(input, length, base); }	4✔
97
98	//static
99	BigInt BigInt::from_bytes_with_max_bits(const uint8_t input[], size_t length, size_t max_bits) {	21,273✔
100	const size_t input_bits = 8 * length;	21,273✔
101
102	BigInt bn;	21,273✔
103	bn.binary_decode(input, length);	21,273✔
104
105	if(input_bits > max_bits) {	21,273✔
106	const size_t bits_to_shift = input_bits - max_bits;	8,941✔
107
108	bn >>= bits_to_shift;	8,941✔
109	}
110
111	return bn;	21,273✔
112	}	×
113
114	/*
115	* Construct a BigInt from an encoded BigInt
116	*/
117	BigInt::BigInt(RandomNumberGenerator& rng, size_t bits, bool set_high_bit) { randomize(rng, bits, set_high_bit); }	21,573✔
118
119	uint8_t BigInt::byte_at(size_t n) const {	286,402✔
120	return get_byte_var(sizeof(word) - (n % sizeof(word)) - 1, word_at(n / sizeof(word)));	286,402✔
121	}
122
123	int32_t BigInt::cmp_word(word other) const {	4,010,899✔
124	if(is_negative()) {	4,010,899✔
125	return -1; // other is positive ...
126	}
127
128	const size_t sw = this->sig_words();	3,977,680✔
129	if(sw > 1) {	3,977,680✔
130	return 1; // must be larger since other is just one word ...
131	}
132
133	return bigint_cmp(this->data(), sw, &other, 1);	1,846,799✔
134	}
135
136	/*
137	* Comparison Function
138	*/
139	int32_t BigInt::cmp(const BigInt& other, bool check_signs) const {	532,958✔
140	if(check_signs) {	532,958✔
141	if(other.is_positive() && this->is_negative()) {	532,831✔
142	return -1;
143	}
144
145	if(other.is_negative() && this->is_positive()) {	532,765✔
146	return 1;
147	}
148
149	if(other.is_negative() && this->is_negative()) {	532,703✔
150	return (-bigint_cmp(this->data(), this->size(), other.data(), other.size()));	66✔
151	}
152	}
153
154	return bigint_cmp(this->data(), this->size(), other.data(), other.size());	532,764✔
155	}
156
157	bool BigInt::is_equal(const BigInt& other) const {	390,346✔
158	if(this->sign() != other.sign()) {	390,346✔
159	return false;
160	}
161
162	return bigint_ct_is_eq(this->data(), this->sig_words(), other.data(), other.sig_words()).is_set();	583,717✔
163	}
164
165	bool BigInt::is_less_than(const BigInt& other) const {	2,758,155✔
166	if(this->is_negative() && other.is_positive()) {	2,758,155✔
167	return true;
168	}
169
170	if(this->is_positive() && other.is_negative()) {	2,758,090✔
171	return false;
172	}
173
174	if(other.is_negative() && this->is_negative()) {	2,758,028✔
175	return bigint_ct_is_lt(other.data(), other.sig_words(), this->data(), this->sig_words()).is_set();	65✔
176	}
177
178	return bigint_ct_is_lt(this->data(), this->sig_words(), other.data(), other.sig_words()).is_set();	5,273,354✔
179	}
180
181	void BigInt::encode_words(word out[], size_t size) const {	1,958,298✔
182	const size_t words = sig_words();	1,958,298✔
183
184	if(words > size) {	1,958,298✔
185	throw Encoding_Error("BigInt::encode_words value too large to encode");	×
186	}
187
188	clear_mem(out, size);	1,958,298✔
189	copy_mem(out, data(), words);	1,958,298✔
190	}	1,958,298✔
191
192	size_t BigInt::Data::calc_sig_words() const {	108,541,127✔
193	const size_t sz = m_reg.size();	108,541,127✔
194	size_t sig = sz;	108,541,127✔
195
196	word sub = 1;	108,541,127✔
197
198	for(size_t i = 0; i != sz; ++i) {	1,858,365,985✔
199	const word w = m_reg[sz - i - 1];	1,749,824,858✔
200	sub &= ct_is_zero(w);	1,749,824,858✔
201	sig -= sub;	1,749,824,858✔
202	}
203
204	/*
205	* This depends on the data so is poisoned, but unpoison it here as
206	* later conditionals are made on the size.
207	*/
208	CT::unpoison(sig);	108,541,127✔
209
210	return sig;	108,541,127✔
211	}
212
213	/*
214	* Return bits {offset...offset+length}
215	*/
216	uint32_t BigInt::get_substring(size_t offset, size_t length) const {	16,404,586✔
217	if(length == 0 \|\| length > 32) {	16,404,586✔
218	throw Invalid_Argument("BigInt::get_substring invalid substring length");	×
219	}
220
221	const uint32_t mask = 0xFFFFFFFF >> (32 - length);	16,404,586✔
222
223	const size_t word_offset = offset / BOTAN_MP_WORD_BITS;	16,404,586✔
224	const size_t wshift = (offset % BOTAN_MP_WORD_BITS);	16,404,586✔
225
226	/*
227	* The substring is contained within one or at most two words. The
228	* offset and length are not secret, so we can perform conditional
229	* operations on those values.
230	*/
231	const word w0 = word_at(word_offset);	16,404,586✔
232
233	if(wshift == 0 \|\| (offset + length) / BOTAN_MP_WORD_BITS == word_offset) {	16,404,586✔
234	return static_cast<uint32_t>(w0 >> wshift) & mask;	15,633,527✔
235	} else {
236	const word w1 = word_at(word_offset + 1);	771,059✔
237	return static_cast<uint32_t>((w0 >> wshift) \| (w1 << (BOTAN_MP_WORD_BITS - wshift))) & mask;	771,059✔
238	}
239	}
240
241	/*
242	* Convert this number to a uint32_t, if possible
243	*/
244	uint32_t BigInt::to_u32bit() const {	34,948✔
245	if(is_negative()) {	34,948✔
246	throw Encoding_Error("BigInt::to_u32bit: Number is negative");	×
247	}
248	if(bits() > 32) {	34,948✔
249	throw Encoding_Error("BigInt::to_u32bit: Number is too big to convert");	15✔
250	}
251
252	uint32_t out = 0;
253	for(size_t i = 0; i != 4; ++i) {	174,665✔
254	out = (out << 8) \| byte_at(3 - i);	139,732✔
255	}
256	return out;	34,933✔
257	}
258
259	/*
260	* Clear bit number n
261	*/
262	void BigInt::clear_bit(size_t n) {	19✔
263	const size_t which = n / BOTAN_MP_WORD_BITS;	19✔
264
265	if(which < size()) {	19✔
266	const word mask = ~(static_cast<word>(1) << (n % BOTAN_MP_WORD_BITS));	19✔
267	m_data.set_word_at(which, word_at(which) & mask);	19✔
268	}
269	}	19✔
270
271	size_t BigInt::bytes() const { return round_up(bits(), 8) / 8; }	213,257✔
272
273	size_t BigInt::top_bits_free() const {	4,392,866✔
274	const size_t words = sig_words();	4,392,866✔
275
276	const word top_word = word_at(words - 1);	35,142,928✔
277	const size_t bits_used = high_bit(top_word);	4,392,866✔
278	CT::unpoison(bits_used);	4,392,866✔
279	return BOTAN_MP_WORD_BITS - bits_used;	4,392,866✔
280	}
281
282	size_t BigInt::bits() const {	2,017,961✔
283	const size_t words = sig_words();	2,017,961✔
284
285	if(words == 0) {	2,017,961✔
286	return 0;
287	}
288
289	const size_t full_words = (words - 1) * BOTAN_MP_WORD_BITS;	2,001,103✔
290	const size_t top_bits = BOTAN_MP_WORD_BITS - top_bits_free();	2,001,103✔
291
292	return full_words + top_bits;	2,001,103✔
293	}
294
295	/*
296	* Return the negation of this number
297	*/
298	BigInt BigInt::operator-() const {	2,901✔
299	BigInt x = (*this);	2,901✔
300	x.flip_sign();	2,901✔
301	return x;	2,901✔
302	}	×
303
304	size_t BigInt::reduce_below(const BigInt& p, secure_vector<word>& ws) {	25,100,599✔
305	if(p.is_negative() \|\| this->is_negative()) {	25,100,599✔
306	throw Invalid_Argument("BigInt::reduce_below both values must be positive");	×
307	}
308
309	const size_t p_words = p.sig_words();	25,100,599✔
310
311	if(size() < p_words + 1) {	25,100,599✔
312	grow_to(p_words + 1);	11,361✔
313	}
314
315	if(ws.size() < p_words + 1) {	25,100,599✔
316	ws.resize(p_words + 1);	654,251✔
317	}
318
319	clear_mem(ws.data(), ws.size());	25,100,599✔
320
321	size_t reductions = 0;
322
323	for(;;) {	64,865,627✔
324	word borrow = bigint_sub3(ws.data(), data(), p_words + 1, p.data(), p_words);	129,731,254✔
325	if(borrow) {	64,865,627✔
326	break;
327	}
328
329	++reductions;	39,765,028✔
330	swap_reg(ws);	64,865,627✔
331	}
332
333	return reductions;	25,100,599✔
334	}
335
336	void BigInt::ct_reduce_below(const BigInt& mod, secure_vector<word>& ws, size_t bound) {	8,380,975✔
337	if(mod.is_negative() \|\| this->is_negative()) {	8,380,975✔
338	throw Invalid_Argument("BigInt::ct_reduce_below both values must be positive");	×
339	}
340
341	const size_t mod_words = mod.sig_words();	8,380,975✔
342
343	grow_to(mod_words);	8,380,975✔
344
345	const size_t sz = size();	8,380,975✔
346
347	ws.resize(sz);	8,380,975✔
348
349	clear_mem(ws.data(), sz);	8,380,975✔
350
351	for(size_t i = 0; i != bound; ++i) {	25,142,925✔
352	word borrow = bigint_sub3(ws.data(), data(), sz, mod.data(), mod_words);	16,761,950✔
353
354	CT::Mask<word>::is_zero(borrow).select_n(mutable_data(), ws.data(), data(), sz);	33,523,900✔
355	}
356	}	8,380,975✔
357
358	/*
359	* Return the absolute value of this number
360	*/
361	BigInt BigInt::abs() const {	1,028✔
362	BigInt x = (*this);	1,028✔
363	x.set_sign(Positive);	1,028✔
364	return x;	1,028✔
365	}
366
367	void BigInt::binary_encode(uint8_t buf[]) const { this->binary_encode(buf, bytes()); }	73,245✔
368
369	/*
370	* Encode this number into bytes
371	*/
372	void BigInt::binary_encode(uint8_t output[], size_t len) const {	105,249✔
373	const size_t full_words = len / sizeof(word);	105,249✔
374	const size_t extra_bytes = len % sizeof(word);	105,249✔
375
376	for(size_t i = 0; i != full_words; ++i) {	1,153,483✔
377	const word w = word_at(i);	1,048,234✔
378	store_be(w, output + (len - (i + 1) * sizeof(word)));	1,048,234✔
379	}
380
381	if(extra_bytes > 0) {	105,249✔
382	const word w = word_at(full_words);	47,584✔
383
384	for(size_t i = 0; i != extra_bytes; ++i) {	195,643✔
385	output[extra_bytes - i - 1] = get_byte_var(sizeof(word) - i - 1, w);	148,059✔
386	}
387	}
388	}	105,249✔
389
390	/*
391	* Set this number to the value in buf
392	*/
393	void BigInt::binary_decode(const uint8_t buf[], size_t length) {	582,392✔
394	clear();	582,392✔
395
396	const size_t full_words = length / sizeof(word);	582,392✔
397	const size_t extra_bytes = length % sizeof(word);	582,392✔
398
399	secure_vector<word> reg((round_up(full_words + (extra_bytes > 0 ? 1 : 0), 8)));	1,307,450✔
400
401	for(size_t i = 0; i != full_words; ++i) {	3,998,576✔
402	reg[i] = load_be<word>(buf + length - sizeof(word) * (i + 1), 0);	3,416,184✔
403	}
404
405	if(extra_bytes > 0) {	582,392✔
406	for(size_t i = 0; i != extra_bytes; ++i) {	1,381,988✔
407	reg[full_words] = (reg[full_words] << 8) \| buf[i];	1,012,180✔
408	}
409	}
410
411	m_data.swap(reg);	582,392✔
412	}	582,392✔
413
414	void BigInt::ct_cond_add(bool predicate, const BigInt& value) {	7,932,737✔
415	if(this->is_negative() \|\| value.is_negative()) {	7,932,737✔
416	throw Invalid_Argument("BigInt::ct_cond_add requires both values to be positive");	×
417	}
418	this->grow_to(1 + value.sig_words());	13,294,542✔
419
420	bigint_cnd_add(static_cast<word>(predicate), this->mutable_data(), this->size(), value.data(), value.sig_words());	7,932,737✔
421	}	7,932,737✔
422
423	void BigInt::ct_cond_swap(bool predicate, BigInt& other) {	152,734,254✔
424	const size_t max_words = std::max(size(), other.size());	152,734,254✔
425	grow_to(max_words);	152,734,254✔
426	other.grow_to(max_words);	152,734,254✔
427
428	bigint_cnd_swap(predicate, this->mutable_data(), other.mutable_data(), max_words);	152,734,254✔
429	}	152,734,254✔
430
431	void BigInt::cond_flip_sign(bool predicate) {	22,098,487✔
432	// This code is assuming Negative == 0, Positive == 1
433
434	const auto mask = CT::Mask<uint8_t>::expand(predicate);	22,098,487✔
435
436	const uint8_t current_sign = static_cast<uint8_t>(sign());	22,098,487✔
437
438	const uint8_t new_sign = mask.select(current_sign ^ 1, current_sign);	22,098,487✔
439
440	set_sign(static_cast<Sign>(new_sign));	22,098,487✔
441	}	22,098,487✔
442
443	void BigInt::ct_cond_assign(bool predicate, const BigInt& other) {	1,772,865✔
444	const size_t t_words = size();	1,772,865✔
445	const size_t o_words = other.size();	1,772,865✔
446
447	if(o_words < t_words) {	1,772,865✔
448	grow_to(o_words);	44,242✔
449	}
450
451	const size_t r_words = std::max(t_words, o_words);	1,772,865✔
452
453	const auto mask = CT::Mask<word>::expand(predicate);	1,772,865✔
454
455	for(size_t i = 0; i != r_words; ++i) {	28,436,036✔
456	const word o_word = other.word_at(i);	26,663,171✔
457	const word t_word = this->word_at(i);	26,663,171✔
458	this->set_word_at(i, mask.select(o_word, t_word));	26,663,171✔
459	}
460
461	const bool different_sign = sign() != other.sign();	1,772,865✔
462	cond_flip_sign(predicate && different_sign);	1,772,865✔
463	}	1,772,865✔
464
465	#if defined(BOTAN_HAS_VALGRIND)
466	void BigInt::const_time_poison() const { CT::poison(m_data.const_data(), m_data.size()); }
467
468	void BigInt::const_time_unpoison() const { CT::unpoison(m_data.const_data(), m_data.size()); }
469	#endif
470
471	} // namespace Botan

randombit / botan / 5123321399

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