1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#ifndef INCLUDED_O3TL_SAFEINT_HXX
#define INCLUDED_O3TL_SAFEINT_HXX
#include <sal/config.h>
#include <limits>
#include <type_traits>
#if defined(_MSC_VER)
#include <safeint.h>
#else
#ifndef __has_builtin
# define __has_builtin(x) 0
#endif
#endif
namespace o3tl
{
template<typename T> inline
typename std::enable_if<std::is_signed<T>::value, T>::type saturating_add(
T a, T b)
{
if (b >= 0) {
if (a <= std::numeric_limits<T>::max() - b) {
return a + b;
} else {
return std::numeric_limits<T>::max();
}
} else {
if (a >= std::numeric_limits<T>::min() + b) {
return a - b;
} else {
return std::numeric_limits<T>::min();
}
}
}
template<typename T> inline
typename std::enable_if<std::is_unsigned<T>::value, T>::type saturating_add(
T a, T b)
{
if (a <= std::numeric_limits<T>::max() - b) {
return a + b;
} else {
return std::numeric_limits<T>::max();
}
}
#if defined(_MSC_VER)
template<typename T> inline bool checked_multiply(T a, T b, T& result)
{
return !msl::utilities::SafeMultiply(a, b, result);
}
template<typename T> inline bool checked_add(T a, T b, T& result)
{
return !msl::utilities::SafeAdd(a, b, result);
}
#elif (defined __GNUC__ && __GNUC__ >= 5) || (__has_builtin(__builtin_mul_overflow) && !(defined ANDROID && defined __clang__))
template<typename T> inline bool checked_multiply(T a, T b, T& result)
{
return __builtin_mul_overflow(a, b, &result);
}
template<typename T> inline bool checked_add(T a, T b, T& result)
{
return __builtin_add_overflow(a, b, &result);
}
#else
//https://www.securecoding.cert.org/confluence/display/c/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow
template<typename T> inline typename std::enable_if<std::is_signed<T>::value, bool>::type checked_multiply(T a, T b, T& result)
{
if (a > 0) { /* a is positive */
if (b > 0) { /* a and b are positive */
if (a > (std::numeric_limits<T>::max() / b)) {
return true; /* Handle error */
}
} else { /* a positive, b nonpositive */
if (b < (std::numeric_limits<T>::min() / a)) {
return true; /* Handle error */
}
} /* a positive, b nonpositive */
} else { /* a is nonpositive */
if (b > 0) { /* a is nonpositive, b is positive */
if (a < (std::numeric_limits<T>::min() / b)) {
return true; /* Handle error */
}
} else { /* a and b are nonpositive */
if ( (a != 0) && (b < (std::numeric_limits<T>::max() / a))) {
return true; /* Handle error */
}
} /* End if a and b are nonpositive */
} /* End if a is nonpositive */
result = a * b;
return false;
}
//https://www.securecoding.cert.org/confluence/display/c/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap
template<typename T> inline typename std::enable_if<std::is_unsigned<T>::value, bool>::type checked_multiply(T a, T b, T& result)
{
if (b && a > std::numeric_limits<T>::max() / b) {
return true;/* Handle error */
}
result = a * b;
return false;
}
//https://www.securecoding.cert.org/confluence/display/c/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow
template<typename T> inline typename std::enable_if<std::is_signed<T>::value, bool>::type checked_add(T a, T b, T& result)
{
if (((b > 0) && (a > (std::numeric_limits<T>::max() - b))) ||
((b < 0) && (a < (std::numeric_limits<T>::min() - b)))) {
return true;
}
result = a + b;
return false;
}
//https://www.securecoding.cert.org/confluence/display/c/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap
template<typename T> inline typename std::enable_if<std::is_unsigned<T>::value, bool>::type checked_add(T a, T b, T& result)
{
if (std::numeric_limits<T>::max() - a < b) {
return true;/* Handle error */
}
result = a + b;
return false;
}
#endif
}
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|
