Botan 2.19.1 Crypto and TLS for C&
mp_numth.cpp
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1/*
2* Fused and Important MP Algorithms
3* (C) 1999-2007 Jack Lloyd
4* 2016 Matthias Gierlings
5*
6* Botan is released under the Simplified BSD License (see license.txt)
7*/
8
9#include <botan/numthry.h>
10#include <botan/internal/mp_core.h>
11#include <botan/internal/rounding.h>
12#include <algorithm>
13
14namespace Botan {
15
16/*
17* Square a BigInt
18*/
20 {
21 BigInt z = x;
23 z.square(ws);
24 return z;
25 }
26
27/*
28* Multiply-Add Operation
29*/
30BigInt mul_add(const BigInt& a, const BigInt& b, const BigInt& c)
31 {
32 if(c.is_negative())
33 throw Invalid_Argument("mul_add: Third argument must be > 0");
34
36 if(a.sign() != b.sign())
37 sign = BigInt::Negative;
38
39 const size_t a_sw = a.sig_words();
40 const size_t b_sw = b.sig_words();
41 const size_t c_sw = c.sig_words();
42
43 BigInt r(sign, std::max(a_sw + b_sw, c_sw) + 1);
44 secure_vector<word> workspace(r.size());
45
47 a.data(), a.size(), a_sw,
48 b.data(), b.size(), b_sw,
49 workspace.data(), workspace.size());
50
51 const size_t r_size = std::max(r.sig_words(), c_sw);
52 bigint_add2(r.mutable_data(), r_size, c.data(), c_sw);
53 return r;
54 }
55
56/*
57* Subtract-Multiply Operation
58*/
59BigInt sub_mul(const BigInt& a, const BigInt& b, const BigInt& c)
60 {
61 if(a.is_negative() || b.is_negative())
62 throw Invalid_Argument("sub_mul: First two arguments must be >= 0");
63
64 BigInt r = a;
65 r -= b;
66 r *= c;
67 return r;
68 }
69
70/*
71* Multiply-Subtract Operation
72*/
73BigInt mul_sub(const BigInt& a, const BigInt& b, const BigInt& c)
74 {
75 if(c.is_negative() || c.is_zero())
76 throw Invalid_Argument("mul_sub: Third argument must be > 0");
77
78 BigInt r = a;
79 r *= b;
80 r -= c;
81 return r;
82 }
83
84}
size_t sig_words() const
Definition: bigint.h:586
word * mutable_data()
Definition: bigint.h:614
size_t size() const
Definition: bigint.h:580
const word * data() const
Definition: bigint.h:620
Sign sign() const
Definition: bigint.h:539
bool is_zero() const
Definition: bigint.h:421
BigInt & square(secure_vector< word > &ws)
Definition: big_ops2.cpp:197
bool is_negative() const
Definition: bigint.h:527
Definition: alg_id.cpp:13
BigInt square(const BigInt &x)
Definition: mp_numth.cpp:19
void bigint_mul(word z[], size_t z_size, const word x[], size_t x_size, size_t x_sw, const word y[], size_t y_size, size_t y_sw, word workspace[], size_t ws_size)
Definition: mp_karat.cpp:298
void bigint_add2(word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:280
BigInt mul_sub(const BigInt &a, const BigInt &b, const BigInt &c)
Definition: mp_numth.cpp:73
BigInt sub_mul(const BigInt &a, const BigInt &b, const BigInt &c)
Definition: mp_numth.cpp:59
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65
BigInt mul_add(const BigInt &a, const BigInt &b, const BigInt &c)
Definition: mp_numth.cpp:30