1/*
2 * Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef WTF_MathExtras_h
27#define WTF_MathExtras_h
28
29#include <algorithm>
30#include <cmath>
31#include <float.h>
32#include <limits>
33#include <stdlib.h>
34
35#if OS(SOLARIS)
36#include <ieeefp.h>
37#endif
38
39#if OS(OPENBSD)
40#include <sys/types.h>
41#include <machine/ieee.h>
42#endif
43
44#if COMPILER(MSVC)
45#if OS(WINCE)
46#include <stdlib.h>
47#endif
48#include <limits>
49#endif
50
51#ifndef M_PI
52const double piDouble = 3.14159265358979323846;
53const float piFloat = 3.14159265358979323846f;
54#else
55const double piDouble = M_PI;
56const float piFloat = static_cast<float>(M_PI);
57#endif
58
59#ifndef M_PI_2
60const double piOverTwoDouble = 1.57079632679489661923;
61const float piOverTwoFloat = 1.57079632679489661923f;
62#else
63const double piOverTwoDouble = M_PI_2;
64const float piOverTwoFloat = static_cast<float>(M_PI_2);
65#endif
66
67#ifndef M_PI_4
68const double piOverFourDouble = 0.785398163397448309616;
69const float piOverFourFloat = 0.785398163397448309616f;
70#else
71const double piOverFourDouble = M_PI_4;
72const float piOverFourFloat = static_cast<float>(M_PI_4);
73#endif
74
75#if OS(DARWIN)
76
77// Work around a bug in the Mac OS X libc where ceil(-0.1) return +0.
78inline double wtf_ceil(double x) { return copysign(ceil(x), x); }
79
80#define ceil(x) wtf_ceil(x)
81
82#endif
83
84#if OS(SOLARIS)
85
86#ifndef isfinite
87inline bool isfinite(double x) { return finite(x) && !isnand(x); }
88#endif
89#ifndef isinf
90inline bool isinf(double x) { return !finite(x) && !isnand(x); }
91#endif
92#ifndef signbit
93inline bool signbit(double x) { return copysign(1.0, x) < 0; }
94#endif
95
96#endif
97
98#if OS(OPENBSD)
99
100#ifndef isfinite
101inline bool isfinite(double x) { return finite(x); }
102#endif
103#ifndef signbit
104inline bool signbit(double x) { struct ieee_double *p = (struct ieee_double *)&x; return p->dbl_sign; }
105#endif
106
107#endif
108
109#if COMPILER(MSVC) || (COMPILER(RVCT) && !(RVCT_VERSION_AT_LEAST(3, 0, 0, 0)))
110
111// We must not do 'num + 0.5' or 'num - 0.5' because they can cause precision loss.
112static double round(double num)
113{
114    double integer = ceil(num);
115    if (num > 0)
116        return integer - num > 0.5 ? integer - 1.0 : integer;
117    return integer - num >= 0.5 ? integer - 1.0 : integer;
118}
119static float roundf(float num)
120{
121    float integer = ceilf(num);
122    if (num > 0)
123        return integer - num > 0.5f ? integer - 1.0f : integer;
124    return integer - num >= 0.5f ? integer - 1.0f : integer;
125}
126inline long long llround(double num) { return static_cast<long long>(round(num)); }
127inline long long llroundf(float num) { return static_cast<long long>(roundf(num)); }
128inline long lround(double num) { return static_cast<long>(round(num)); }
129inline long lroundf(float num) { return static_cast<long>(roundf(num)); }
130inline double trunc(double num) { return num > 0 ? floor(num) : ceil(num); }
131
132#endif
133
134#if COMPILER(MSVC)
135// The 64bit version of abs() is already defined in stdlib.h which comes with VC10
136#if COMPILER(MSVC9_OR_LOWER)
137inline long long abs(long long num) { return _abs64(num); }
138#endif
139
140inline bool isinf(double num) { return !_finite(num) && !_isnan(num); }
141inline bool isnan(double num) { return !!_isnan(num); }
142inline bool signbit(double num) { return _copysign(1.0, num) < 0; }
143
144inline double nextafter(double x, double y) { return _nextafter(x, y); }
145inline float nextafterf(float x, float y) { return x > y ? x - FLT_EPSILON : x + FLT_EPSILON; }
146
147inline double copysign(double x, double y) { return _copysign(x, y); }
148inline int isfinite(double x) { return _finite(x); }
149
150// MSVC's math.h does not currently supply log2.
151inline double log2(double num)
152{
153    // This constant is roughly M_LN2, which is not provided by default on Windows.
154    return log(num) / 0.693147180559945309417232121458176568;
155}
156
157// Work around a bug in Win, where atan2(+-infinity, +-infinity) yields NaN instead of specific values.
158inline double wtf_atan2(double x, double y)
159{
160    double posInf = std::numeric_limits<double>::infinity();
161    double negInf = -std::numeric_limits<double>::infinity();
162    double nan = std::numeric_limits<double>::quiet_NaN();
163
164    double result = nan;
165
166    if (x == posInf && y == posInf)
167        result = piOverFourDouble;
168    else if (x == posInf && y == negInf)
169        result = 3 * piOverFourDouble;
170    else if (x == negInf && y == posInf)
171        result = -piOverFourDouble;
172    else if (x == negInf && y == negInf)
173        result = -3 * piOverFourDouble;
174    else
175        result = ::atan2(x, y);
176
177    return result;
178}
179
180// Work around a bug in the Microsoft CRT, where fmod(x, +-infinity) yields NaN instead of x.
181inline double wtf_fmod(double x, double y) { return (!isinf(x) && isinf(y)) ? x : fmod(x, y); }
182
183// Work around a bug in the Microsoft CRT, where pow(NaN, 0) yields NaN instead of 1.
184inline double wtf_pow(double x, double y) { return y == 0 ? 1 : pow(x, y); }
185
186#define atan2(x, y) wtf_atan2(x, y)
187#define fmod(x, y) wtf_fmod(x, y)
188#define pow(x, y) wtf_pow(x, y)
189
190#endif // COMPILER(MSVC)
191
192inline double deg2rad(double d)  { return d * piDouble / 180.0; }
193inline double rad2deg(double r)  { return r * 180.0 / piDouble; }
194inline double deg2grad(double d) { return d * 400.0 / 360.0; }
195inline double grad2deg(double g) { return g * 360.0 / 400.0; }
196inline double turn2deg(double t) { return t * 360.0; }
197inline double deg2turn(double d) { return d / 360.0; }
198inline double rad2grad(double r) { return r * 200.0 / piDouble; }
199inline double grad2rad(double g) { return g * piDouble / 200.0; }
200
201inline float deg2rad(float d)  { return d * piFloat / 180.0f; }
202inline float rad2deg(float r)  { return r * 180.0f / piFloat; }
203inline float deg2grad(float d) { return d * 400.0f / 360.0f; }
204inline float grad2deg(float g) { return g * 360.0f / 400.0f; }
205inline float turn2deg(float t) { return t * 360.0f; }
206inline float deg2turn(float d) { return d / 360.0f; }
207inline float rad2grad(float r) { return r * 200.0f / piFloat; }
208inline float grad2rad(float g) { return g * piFloat / 200.0f; }
209
210inline int clampToInteger(double d)
211{
212    const double minIntAsDouble = std::numeric_limits<int>::min();
213    const double maxIntAsDouble = std::numeric_limits<int>::max();
214    return static_cast<int>(std::max(std::min(d, maxIntAsDouble), minIntAsDouble));
215}
216
217inline int clampToPositiveInteger(double d)
218{
219    const double maxIntAsDouble = std::numeric_limits<int>::max();
220    return static_cast<int>(std::max<double>(std::min(d, maxIntAsDouble), 0));
221}
222
223inline int clampToInteger(float x)
224{
225    static const int s_intMax = std::numeric_limits<int>::max();
226    static const int s_intMin = std::numeric_limits<int>::min();
227
228    if (x >= static_cast<float>(s_intMax))
229        return s_intMax;
230    if (x < static_cast<float>(s_intMin))
231        return s_intMin;
232    return static_cast<int>(x);
233}
234
235inline int clampToPositiveInteger(float x)
236{
237    static const int s_intMax = std::numeric_limits<int>::max();
238
239    if (x >= static_cast<float>(s_intMax))
240        return s_intMax;
241    if (x < 0)
242        return 0;
243    return static_cast<int>(x);
244}
245
246inline int clampToInteger(unsigned value)
247{
248    return static_cast<int>(std::min(value, static_cast<unsigned>(std::numeric_limits<int>::max())));
249}
250
251#if !COMPILER(MSVC) && !(COMPILER(RVCT) && PLATFORM(BREWMP)) && !OS(SOLARIS) && !OS(SYMBIAN)
252using std::isfinite;
253using std::isinf;
254using std::isnan;
255using std::signbit;
256#endif
257
258#endif // #ifndef WTF_MathExtras_h
259