1/*
2Copyright (C) 1999-2007 The Botan Project. All rights reserved.
3
4Redistribution and use in source and binary forms, for any use, with or without
5modification, is permitted provided that the following conditions are met:
6
71. Redistributions of source code must retain the above copyright notice, this
8list of conditions, and the following disclaimer.
9
102. Redistributions in binary form must reproduce the above copyright notice,
11this list of conditions, and the following disclaimer in the documentation
12and/or other materials provided with the distribution.
13
14THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) "AS IS" AND ANY EXPRESS OR IMPLIED
15WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
16MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.
17
18IN NO EVENT SHALL THE AUTHOR(S) OR CONTRIBUTOR(S) BE LIABLE FOR ANY DIRECT,
19INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
20BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
22LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
23OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25*/
26// LICENSEHEADER_END
27namespace QCA { // WRAPNS_LINE
28/*************************************************
29 * BigInt Binary Operators Source File *
30 * (C) 1999-2007 The Botan Project *
31 *************************************************/
32
33} // WRAPNS_LINE
34#include <botan/bigint.h>
35namespace QCA { // WRAPNS_LINE
36} // WRAPNS_LINE
37#include <botan/numthry.h>
38namespace QCA { // WRAPNS_LINE
39} // WRAPNS_LINE
40#include <botan/mp_core.h>
41namespace QCA { // WRAPNS_LINE
42} // WRAPNS_LINE
43#include <botan/bit_ops.h>
44namespace QCA { // WRAPNS_LINE
45} // WRAPNS_LINE
46#include <algorithm>
47namespace QCA { // WRAPNS_LINE
48
49namespace Botan {
50
51/*************************************************
52 * Addition Operator *
53 *************************************************/
54BigInt operator+(const BigInt &x, const BigInt &y)
55{
56 const u32bit x_sw = x.sig_words(), y_sw = y.sig_words();
57
58#ifdef BOTAN_TYPES_QT
59 BigInt z(x.sign(), qMax(a: x_sw, b: y_sw) + 1);
60#else
61 BigInt z(x.sign(), std::max(x_sw, y_sw) + 1);
62#endif
63
64 if ((x.sign() == y.sign()))
65 bigint_add3(z.get_reg(), x.data(), x_sw, y.data(), y_sw);
66 else {
67 s32bit relative_size = bigint_cmp(x.data(), x_sw, y.data(), y_sw);
68
69 if (relative_size < 0) {
70 bigint_sub3(z.get_reg(), y.data(), y_sw, x.data(), x_sw);
71 z.set_sign(y.sign());
72 } else if (relative_size == 0)
73 z.set_sign(BigInt::Positive);
74 else if (relative_size > 0)
75 bigint_sub3(z.get_reg(), x.data(), x_sw, y.data(), y_sw);
76 }
77
78 return z;
79}
80
81/*************************************************
82 * Subtraction Operator *
83 *************************************************/
84BigInt operator-(const BigInt &x, const BigInt &y)
85{
86 const u32bit x_sw = x.sig_words(), y_sw = y.sig_words();
87
88 s32bit relative_size = bigint_cmp(x.data(), x_sw, y.data(), y_sw);
89
90#ifdef BOTAN_TYPES_QT
91 BigInt z(BigInt::Positive, qMax(a: x_sw, b: y_sw) + 1);
92#else
93 BigInt z(BigInt::Positive, std::max(x_sw, y_sw) + 1);
94#endif
95
96 if (relative_size < 0) {
97 if (x.sign() == y.sign())
98 bigint_sub3(z.get_reg(), y.data(), y_sw, x.data(), x_sw);
99 else
100 bigint_add3(z.get_reg(), x.data(), x_sw, y.data(), y_sw);
101 z.set_sign(y.reverse_sign());
102 } else if (relative_size == 0) {
103 if (x.sign() != y.sign())
104 bigint_shl2(z.get_reg(), x.data(), x_sw, 0, 1);
105 } else if (relative_size > 0) {
106 if (x.sign() == y.sign())
107 bigint_sub3(z.get_reg(), x.data(), x_sw, y.data(), y_sw);
108 else
109 bigint_add3(z.get_reg(), x.data(), x_sw, y.data(), y_sw);
110 z.set_sign(x.sign());
111 }
112 return z;
113}
114
115/*************************************************
116 * Multiplication Operator *
117 *************************************************/
118BigInt operator*(const BigInt &x, const BigInt &y)
119{
120 const u32bit x_sw = x.sig_words(), y_sw = y.sig_words();
121
122 BigInt z(BigInt::Positive, x.size() + y.size());
123
124 if (x_sw == 1 && y_sw)
125 bigint_linmul3(z.get_reg(), y.data(), y_sw, x.word_at(n: 0));
126 else if (y_sw == 1 && x_sw)
127 bigint_linmul3(z.get_reg(), x.data(), x_sw, y.word_at(n: 0));
128 else if (x_sw && y_sw) {
129 SecureVector<word> workspace(z.size());
130 bigint_mul(z.get_reg(), z.size(), workspace, x.data(), x.size(), x_sw, y.data(), y.size(), y_sw);
131 }
132
133 if (x_sw && y_sw && x.sign() != y.sign())
134 z.flip_sign();
135 return z;
136}
137
138/*************************************************
139 * Division Operator *
140 *************************************************/
141BigInt operator/(const BigInt &x, const BigInt &y)
142{
143 BigInt q, r;
144 divide(x, y, q, r);
145 return q;
146}
147
148/*************************************************
149 * Modulo Operator *
150 *************************************************/
151BigInt operator%(const BigInt &n, const BigInt &mod)
152{
153 if (mod.is_zero())
154 throw BigInt::DivideByZero();
155 if (mod.is_negative())
156 throw Invalid_Argument("BigInt::operator%: modulus must be > 0");
157 if (n.is_positive() && mod.is_positive() && n < mod)
158 return n;
159
160 BigInt q, r;
161 divide(n, mod, q, r);
162 return r;
163}
164
165/*************************************************
166 * Modulo Operator *
167 *************************************************/
168word operator%(const BigInt &n, word mod)
169{
170 if (mod == 0)
171 throw BigInt::DivideByZero();
172 if (power_of_2(mod))
173 return (n.word_at(n: 0) & (mod - 1));
174
175 word remainder = 0;
176
177 for (u32bit j = n.sig_words(); j > 0; --j)
178 remainder = bigint_modop(remainder, n.word_at(n: j - 1), mod);
179
180 if (remainder && n.sign() == BigInt::Negative)
181 return mod - remainder;
182 return remainder;
183}
184
185/*************************************************
186 * Left Shift Operator *
187 *************************************************/
188BigInt operator<<(const BigInt &x, u32bit shift)
189{
190 if (shift == 0)
191 return x;
192
193 const u32bit shift_words = shift / MP_WORD_BITS, shift_bits = shift % MP_WORD_BITS;
194
195 const u32bit x_sw = x.sig_words();
196
197 BigInt y(x.sign(), x_sw + shift_words + (shift_bits ? 1 : 0));
198 bigint_shl2(y.get_reg(), x.data(), x_sw, shift_words, shift_bits);
199 return y;
200}
201
202/*************************************************
203 * Right Shift Operator *
204 *************************************************/
205BigInt operator>>(const BigInt &x, u32bit shift)
206{
207 if (shift == 0)
208 return x;
209 if (x.bits() <= shift)
210 return 0;
211
212 const u32bit shift_words = shift / MP_WORD_BITS, shift_bits = shift % MP_WORD_BITS, x_sw = x.sig_words();
213
214 BigInt y(x.sign(), x_sw - shift_words);
215 bigint_shr2(y.get_reg(), x.data(), x_sw, shift_words, shift_bits);
216 return y;
217}
218
219}
220} // WRAPNS_LINE
221

source code of qca/src/botantools/botan/big_ops3.cpp