summaryrefslogtreecommitdiffstats
path: root/src/corelib/global/qnumeric_p.h
blob: b7f7d5187c3f82e84c313d4e8778387f27f7fa42 (plain)
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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Copyright (C) 2016 Intel Corporation.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QNUMERIC_P_H
#define QNUMERIC_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include "QtCore/qglobal.h"
#include <cmath>
#include <limits>

#if defined(Q_CC_MSVC)
#  include <intrin.h>
#elif defined(Q_CC_INTEL)
#  include <immintrin.h>    // for _addcarry_u<nn>
#endif

#if defined(Q_CC_MSVC)
#include <float.h>
#endif

#if !defined(Q_CC_MSVC) && (defined(Q_OS_QNX) || !defined(__cplusplus) || __cplusplus < 201103L)
#include <math.h>
QT_BEGIN_NAMESPACE
namespace qnumeric_std_wrapper {
// the 'using namespace std' below is cases where the stdlib already put the math.h functions in the std namespace and undefined the macros.
static inline bool math_h_isnan(double d) { using namespace std; return isnan(d); }
static inline bool math_h_isinf(double d) { using namespace std; return isinf(d); }
static inline bool math_h_isfinite(double d) { using namespace std; return isfinite(d); }
static inline bool math_h_isnan(float f) { using namespace std; return isnan(f); }
static inline bool math_h_isinf(float f) { using namespace std; return isinf(f); }
static inline bool math_h_isfinite(float f) { using namespace std; return isfinite(f); }
}
QT_END_NAMESPACE
// These macros from math.h conflict with the real functions in the std namespace.
#undef signbit
#undef isnan
#undef isinf
#undef isfinite
#endif

QT_BEGIN_NAMESPACE

namespace qnumeric_std_wrapper {
#if defined(Q_CC_MSVC) && _MSC_VER < 1800
static inline bool isnan(double d) { return !!_isnan(d); }
static inline bool isinf(double d) { return !_finite(d) && !_isnan(d); }
static inline bool isfinite(double d) { return !!_finite(d); }
static inline bool isnan(float f) { return !!_isnan(f); }
static inline bool isinf(float f) { return !_finite(f) && !_isnan(f); }
static inline bool isfinite(float f) { return !!_finite(f); }
#elif !defined(Q_CC_MSVC) && (defined(Q_OS_QNX) || !defined(__cplusplus) || __cplusplus < 201103L)
static inline bool isnan(double d) { return math_h_isnan(d); }
static inline bool isinf(double d) { return math_h_isinf(d); }
static inline bool isfinite(double d) { return math_h_isfinite(d); }
static inline bool isnan(float f) { return math_h_isnan(f); }
static inline bool isinf(float f) { return math_h_isinf(f); }
static inline bool isfinite(float f) { return math_h_isfinite(f); }
#else
static inline bool isnan(double d) { return std::isnan(d); }
static inline bool isinf(double d) { return std::isinf(d); }
static inline bool isfinite(double d) { return std::isfinite(d); }
static inline bool isnan(float f) { return std::isnan(f); }
static inline bool isinf(float f) { return std::isinf(f); }
static inline bool isfinite(float f) { return std::isfinite(f); }
#endif
}

Q_DECL_CONSTEXPR static inline double qt_inf() Q_DECL_NOEXCEPT
{
    Q_STATIC_ASSERT_X(std::numeric_limits<double>::has_infinity,
                      "platform has no definition for infinity for type double");
    return std::numeric_limits<double>::infinity();
}

// Signaling NaN
Q_DECL_CONSTEXPR static inline double qt_snan() Q_DECL_NOEXCEPT
{
    Q_STATIC_ASSERT_X(std::numeric_limits<double>::has_signaling_NaN,
                      "platform has no definition for signaling NaN for type double");
    return std::numeric_limits<double>::signaling_NaN();
}

// Quiet NaN
Q_DECL_CONSTEXPR static inline double qt_qnan() Q_DECL_NOEXCEPT
{
    Q_STATIC_ASSERT_X(std::numeric_limits<double>::has_quiet_NaN,
                      "platform has no definition for quiet NaN for type double");
    return std::numeric_limits<double>::quiet_NaN();
}

static inline bool qt_is_inf(double d)
{
    return qnumeric_std_wrapper::isinf(d);
}

static inline bool qt_is_nan(double d)
{
    return qnumeric_std_wrapper::isnan(d);
}

static inline bool qt_is_finite(double d)
{
    return qnumeric_std_wrapper::isfinite(d);
}

static inline bool qt_is_inf(float f)
{
    return qnumeric_std_wrapper::isinf(f);
}

static inline bool qt_is_nan(float f)
{
    return qnumeric_std_wrapper::isnan(f);
}

static inline bool qt_is_finite(float f)
{
    return qnumeric_std_wrapper::isfinite(f);
}

//
// Unsigned overflow math
//
namespace {
template <typename T> inline typename QtPrivate::QEnableIf<QtPrivate::is_unsigned<T>::value, bool>::Type
add_overflow(T v1, T v2, T *r)
{
    // unsigned additions are well-defined
    *r = v1 + v2;
    return v1 > T(v1 + v2);
}

template <typename T> inline typename QtPrivate::QEnableIf<QtPrivate::is_unsigned<T>::value, bool>::Type
mul_overflow(T v1, T v2, T *r)
{
    // use the next biggest type
    // Note: for 64-bit systems where __int128 isn't supported, this will cause an error.
    // A fallback is present below.
    typedef typename QIntegerForSize<sizeof(T) * 2>::Unsigned Larger;
    Larger lr = Larger(v1) * Larger(v2);
    *r = T(lr);
    return lr > std::numeric_limits<T>::max();
}

#if defined(__SIZEOF_INT128__)
#  define HAVE_MUL64_OVERFLOW
#endif

// GCC 5 and Clang have builtins to detect overflows
#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_uadd_overflow)
template <> inline bool add_overflow(unsigned v1, unsigned v2, unsigned *r)
{ return __builtin_uadd_overflow(v1, v2, r); }
#endif
#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_uaddl_overflow)
template <> inline bool add_overflow(unsigned long v1, unsigned long v2, unsigned long *r)
{ return __builtin_uaddl_overflow(v1, v2, r); }
#endif
#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_uaddll_overflow)
template <> inline bool add_overflow(unsigned long long v1, unsigned long long v2, unsigned long long *r)
{ return __builtin_uaddll_overflow(v1, v2, r); }
#endif

#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_umul_overflow)
template <> inline bool mul_overflow(unsigned v1, unsigned v2, unsigned *r)
{ return __builtin_umul_overflow(v1, v2, r); }
#endif
#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_umull_overflow)
template <> inline bool mul_overflow(unsigned long v1, unsigned long v2, unsigned long *r)
{ return __builtin_umull_overflow(v1, v2, r); }
#endif
#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_umulll_overflow)
template <> inline bool mul_overflow(unsigned long long v1, unsigned long long v2, unsigned long long *r)
{ return __builtin_umulll_overflow(v1, v2, r); }
#  define HAVE_MUL64_OVERFLOW
#endif

#if ((defined(Q_CC_MSVC) && _MSC_VER >= 1800) || defined(Q_CC_INTEL)) && defined(Q_PROCESSOR_X86) && !QT_HAS_BUILTIN(__builtin_uadd_overflow)
template <> inline bool add_overflow(unsigned v1, unsigned v2, unsigned *r)
{ return _addcarry_u32(0, v1, v2, r); }
#  ifdef Q_CC_MSVC      // longs are 32-bit
template <> inline bool add_overflow(unsigned long v1, unsigned long v2, unsigned long *r)
{ return _addcarry_u32(0, v1, v2, reinterpret_cast<unsigned *>(r)); }
#  endif
#endif
#if ((defined(Q_CC_MSVC) && _MSC_VER >= 1800) || defined(Q_CC_INTEL)) && defined(Q_PROCESSOR_X86_64) && !QT_HAS_BUILTIN(__builtin_uadd_overflow)
template <> inline bool add_overflow(quint64 v1, quint64 v2, quint64 *r)
{ return _addcarry_u64(0, v1, v2, reinterpret_cast<unsigned __int64 *>(r)); }
#  ifndef Q_CC_MSVC      // longs are 64-bit
template <> inline bool add_overflow(unsigned long v1, unsigned long v2, unsigned long *r)
{ return _addcarry_u64(0, v1, v2, reinterpret_cast<unsigned __int64 *>(r)); }
#  endif
#endif

#if defined(Q_CC_MSVC) && (defined(Q_PROCESSOR_X86_64) || defined(Q_PROCESSOR_IA64)) && !QT_HAS_BUILTIN(__builtin_uadd_overflow)
#pragma intrinsic(_umul128)
template <> inline bool mul_overflow(quint64 v1, quint64 v2, quint64 *r)
{
    // use 128-bit multiplication with the _umul128 intrinsic
    // https://msdn.microsoft.com/en-us/library/3dayytw9.aspx
    quint64 high;
    *r = _umul128(v1, v2, &high);
    return high;
}
#  define HAVE_MUL64_OVERFLOW
#endif

#if !defined(HAVE_MUL64_OVERFLOW) && defined(__LP64__)
// no 128-bit multiplication, we need to figure out with a slow division
template <> inline bool mul_overflow(quint64 v1, quint64 v2, quint64 *r)
{
    if (v2 && v1 > std::numeric_limits<quint64>::max() / v2)
        return true;
    *r = v1 * v2;
    return false;
}
template <> inline bool mul_overflow(unsigned long v1, unsigned long v2, unsigned long *r)
{
    return mul_overflow<quint64>(v1, v2, reinterpret_cast<quint64 *>(r));
}
#else
#  undef HAVE_MUL64_OVERFLOW
#endif

//
// Signed overflow math
//
// In C++, signed overflow math is Undefined Behavior. However, many CPUs do implement some way to
// check for overflow. Some compilers expose intrinsics to use this functionality. If the no
// intrinsic is exposed, overflow checking can be done by widening the result type and "manually"
// checking for overflow. Or, alternatively, by using inline assembly to use the CPU features.
//
// Only int overflow checking is implemented, because it's the only one used.
#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_sadd_overflow)
inline bool add_overflow(int v1, int v2, int *r)
{ return __builtin_sadd_overflow(v1, v2, r); }
#elif defined(Q_CC_GNU) && defined(Q_PROCESSOR_X86)
inline bool add_overflow(int v1, int v2, int *r)
{
    quint8 overflow = 0;
    int res = v1;

    asm ("addl %2, %1\n"
         "seto %0"
         : "=q" (overflow), "=r" (res)
         : "r" (v2), "1" (res)
         : "cc"
    );
    *r = res;
    return overflow;
}
#else
inline bool add_overflow(int v1, int v2, int *r)
{
    qint64 t = qint64(v1) + v2;
    *r = static_cast<int>(t);
    return t > std::numeric_limits<int>::max() || t < std::numeric_limits<int>::min();
}
#endif

#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_ssub_overflow)
inline bool sub_overflow(int v1, int v2, int *r)
{ return __builtin_ssub_overflow(v1, v2, r); }
#elif defined(Q_CC_GNU) && defined(Q_PROCESSOR_X86)
inline bool sub_overflow(int v1, int v2, int *r)
{
    quint8 overflow = 0;
    int res = v1;

    asm ("subl %2, %1\n"
         "seto %0"
         : "=q" (overflow), "=r" (res)
         : "r" (v2), "1" (res)
         : "cc"
    );
    *r = res;
    return overflow;
}
#else
inline bool sub_overflow(int v1, int v2, int *r)
{
    qint64 t = qint64(v1) - v2;
    *r = static_cast<int>(t);
    return t > std::numeric_limits<int>::max() || t < std::numeric_limits<int>::min();
}
#endif

#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && Q_CC_GNU >= 500) || QT_HAS_BUILTIN(__builtin_smul_overflow)
inline bool mul_overflow(int v1, int v2, int *r)
{ return __builtin_smul_overflow(v1, v2, r); }
#elif defined(Q_CC_GNU) && defined(Q_PROCESSOR_X86)
inline bool mul_overflow(int v1, int v2, int *r)
{
    quint8 overflow = 0;
    int res = v1;

    asm ("imul %2, %1\n"
         "seto %0"
         : "=q" (overflow), "=r" (res)
         : "r" (v2), "1" (res)
         : "cc"
    );
    *r = res;
    return overflow;
}
#else
inline bool mul_overflow(int v1, int v2, int *r)
{
    qint64 t = qint64(v1) * v2;
    *r = static_cast<int>(t);
    return t > std::numeric_limits<int>::max() || t < std::numeric_limits<int>::min();
}
#endif

}

QT_END_NAMESPACE

#endif // QNUMERIC_P_H