Move Source/WTF/wtf to Source/wtf

Source/WTF/wtf/MathExtras.h

-/*
- * Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
- */
-
-#ifndef WTF_MathExtras_h
-#define WTF_MathExtras_h
-
-#include <algorithm>
-#include <cmath>
-#include <float.h>
-#include <limits>
-#include <stdint.h>
-#include <stdlib.h>
-#include <wtf/StdLibExtras.h>
-
-#if OS(SOLARIS)
-#include <ieeefp.h>
-#endif
-
-#if OS(OPENBSD)
-#include <sys/types.h>
-#include <machine/ieee.h>
-#endif
-
-#if OS(QNX)
-// FIXME: Look into a way to have cmath import its functions into both the standard and global
-// namespace. For now, we include math.h since the QNX cmath header only imports its functions
-// into the standard namespace.
-#include <math.h>
-#endif
-
-#ifndef M_PI
-const double piDouble = 3.14159265358979323846;
-const float piFloat = 3.14159265358979323846f;
-#else
-const double piDouble = M_PI;
-const float piFloat = static_cast<float>(M_PI);
-#endif
-
-#ifndef M_PI_2
-const double piOverTwoDouble = 1.57079632679489661923;
-const float piOverTwoFloat = 1.57079632679489661923f;
-#else
-const double piOverTwoDouble = M_PI_2;
-const float piOverTwoFloat = static_cast<float>(M_PI_2);
-#endif
-
-#ifndef M_PI_4
-const double piOverFourDouble = 0.785398163397448309616;
-const float piOverFourFloat = 0.785398163397448309616f;
-#else
-const double piOverFourDouble = M_PI_4;
-const float piOverFourFloat = static_cast<float>(M_PI_4);
-#endif
-
-#if OS(DARWIN)
-
-// Work around a bug in the Mac OS X libc where ceil(-0.1) return +0.
-inline double wtf_ceil(double x) { return copysign(ceil(x), x); }
-
-#define ceil(x) wtf_ceil(x)
-
-#endif
-
-#if OS(SOLARIS)
-
-namespace std {
-
-#ifndef isfinite
-inline bool isfinite(double x) { return finite(x) && !isnand(x); }
-#endif
-#ifndef signbit
-inline bool signbit(double x) { return copysign(1.0, x) < 0; }
-#endif
-#ifndef isinf
-inline bool isinf(double x) { return !finite(x) && !isnand(x); }
-#endif
-
-} // namespace std
-
-#endif
-
-#if OS(OPENBSD)
-
-namespace std {
-
-#ifndef isfinite
-inline bool isfinite(double x) { return finite(x); }
-#endif
-#ifndef signbit
-inline bool signbit(double x) { struct ieee_double *p = (struct ieee_double *)&x; return p->dbl_sign; }
-#endif
-
-} // namespace std
-
-#endif
-
-#if COMPILER(MSVC)
-
-// We must not do 'num + 0.5' or 'num - 0.5' because they can cause precision loss.
-static double round(double num)
-{
-    double integer = ceil(num);
-    if (num > 0)
-        return integer - num > 0.5 ? integer - 1.0 : integer;
-    return integer - num >= 0.5 ? integer - 1.0 : integer;
-}
-static float roundf(float num)
-{
-    float integer = ceilf(num);
-    if (num > 0)
-        return integer - num > 0.5f ? integer - 1.0f : integer;
-    return integer - num >= 0.5f ? integer - 1.0f : integer;
-}
-inline long long llround(double num) { return static_cast<long long>(round(num)); }
-inline long long llroundf(float num) { return static_cast<long long>(roundf(num)); }
-inline long lround(double num) { return static_cast<long>(round(num)); }
-inline long lroundf(float num) { return static_cast<long>(roundf(num)); }
-inline double trunc(double num) { return num > 0 ? floor(num) : ceil(num); }
-
-#endif
-
-#if COMPILER(GCC) && OS(QNX)
-// The stdlib on QNX doesn't contain long abs(long). See PR #104666.
-inline long long abs(long num) { return labs(num); }
-#endif
-
-#if OS(ANDROID) || COMPILER(MSVC)
-// ANDROID and MSVC's math.h does not currently supply log2 or log2f.
-inline double log2(double num)
-{
-    // This constant is roughly M_LN2, which is not provided by default on Windows and Android.
-    return log(num) / 0.693147180559945309417232121458176568;
-}
-
-inline float log2f(float num)
-{
-    // This constant is roughly M_LN2, which is not provided by default on Windows and Android.
-    return logf(num) / 0.693147180559945309417232121458176568f;
-}
-#endif
-
-#if COMPILER(MSVC)
-// The 64bit version of abs() is already defined in stdlib.h which comes with VC10
-#if COMPILER(MSVC9_OR_LOWER)
-inline long long abs(long long num) { return _abs64(num); }
-#endif
-
-namespace std {
-
-inline bool isinf(double num) { return !_finite(num) && !_isnan(num); }
-inline bool isnan(double num) { return !!_isnan(num); }
-inline bool isfinite(double x) { return _finite(x); }
-inline bool signbit(double num) { return _copysign(1.0, num) < 0; }
-
-} // namespace std
-
-inline double nextafter(double x, double y) { return _nextafter(x, y); }
-inline float nextafterf(float x, float y) { return x > y ? x - FLT_EPSILON : x + FLT_EPSILON; }
-
-inline double copysign(double x, double y) { return _copysign(x, y); }
-
-// Work around a bug in Win, where atan2(+-infinity, +-infinity) yields NaN instead of specific values.
-inline double wtf_atan2(double x, double y)
-{
-    double posInf = std::numeric_limits<double>::infinity();
-    double negInf = -std::numeric_limits<double>::infinity();
-    double nan = std::numeric_limits<double>::quiet_NaN();
-
-    double result = nan;
-
-    if (x == posInf && y == posInf)
-        result = piOverFourDouble;
-    else if (x == posInf && y == negInf)
-        result = 3 * piOverFourDouble;
-    else if (x == negInf && y == posInf)
-        result = -piOverFourDouble;
-    else if (x == negInf && y == negInf)
-        result = -3 * piOverFourDouble;
-    else
-        result = ::atan2(x, y);
-
-    return result;
-}
-
-// Work around a bug in the Microsoft CRT, where fmod(x, +-infinity) yields NaN instead of x.
-inline double wtf_fmod(double x, double y) { return (!std::isinf(x) && std::isinf(y)) ? x : fmod(x, y); }
-
-// Work around a bug in the Microsoft CRT, where pow(NaN, 0) yields NaN instead of 1.
-inline double wtf_pow(double x, double y) { return y == 0 ? 1 : pow(x, y); }
-
-#define atan2(x, y) wtf_atan2(x, y)
-#define fmod(x, y) wtf_fmod(x, y)
-#define pow(x, y) wtf_pow(x, y)
-
-// MSVC's math functions do not bring lrint.
-inline long int lrint(double flt)
-{
-    int64_t intgr;
-#if CPU(X86)
-    __asm {
-        fld flt
-        fistp intgr
-    };
-#else
-    ASSERT(std::isfinite(flt));
-    double rounded = round(flt);
-    intgr = static_cast<int64_t>(rounded);
-    // If the fractional part is exactly 0.5, we need to check whether
-    // the rounded result is even. If it is not we need to add 1 to
-    // negative values and subtract one from positive values.
-    if ((fabs(intgr - flt) == 0.5) & intgr)
-        intgr -= ((intgr >> 62) | 1); // 1 with the sign of result, i.e. -1 or 1.
-#endif
-    return static_cast<long int>(intgr);
-}
-
-#endif // COMPILER(MSVC)
-
-inline double deg2rad(double d)  { return d * piDouble / 180.0; }
-inline double rad2deg(double r)  { return r * 180.0 / piDouble; }
-inline double deg2grad(double d) { return d * 400.0 / 360.0; }
-inline double grad2deg(double g) { return g * 360.0 / 400.0; }
-inline double turn2deg(double t) { return t * 360.0; }
-inline double deg2turn(double d) { return d / 360.0; }
-inline double rad2grad(double r) { return r * 200.0 / piDouble; }
-inline double grad2rad(double g) { return g * piDouble / 200.0; }
-
-inline float deg2rad(float d)  { return d * piFloat / 180.0f; }
-inline float rad2deg(float r)  { return r * 180.0f / piFloat; }
-inline float deg2grad(float d) { return d * 400.0f / 360.0f; }
-inline float grad2deg(float g) { return g * 360.0f / 400.0f; }
-inline float turn2deg(float t) { return t * 360.0f; }
-inline float deg2turn(float d) { return d / 360.0f; }
-inline float rad2grad(float r) { return r * 200.0f / piFloat; }
-inline float grad2rad(float g) { return g * piFloat / 200.0f; }
-
-// std::numeric_limits<T>::min() returns the smallest positive value for floating point types
-template<typename T> inline T defaultMinimumForClamp() { return std::numeric_limits<T>::min(); }
-template<> inline float defaultMinimumForClamp() { return -std::numeric_limits<float>::max(); }
-template<> inline double defaultMinimumForClamp() { return -std::numeric_limits<double>::max(); }
-template<typename T> inline T defaultMaximumForClamp() { return std::numeric_limits<T>::max(); }
-
-template<typename T> inline T clampTo(double value, T min = defaultMinimumForClamp<T>(), T max = defaultMaximumForClamp<T>())
-{
-    if (value >= static_cast<double>(max))
-        return max;
-    if (value <= static_cast<double>(min))
-        return min;
-    return static_cast<T>(value);
-}
-template<> inline long long int clampTo(double, long long int, long long int); // clampTo does not support long long ints.
-
-inline int clampToInteger(double value)
-{
-    return clampTo<int>(value);
-}
-
-inline float clampToFloat(double value)
-{
-    return clampTo<float>(value);
-}
-
-inline int clampToPositiveInteger(double value)
-{
-    return clampTo<int>(value, 0);
-}
-
-inline int clampToInteger(float value)
-{
-    return clampTo<int>(value);
-}
-
-inline int clampToInteger(unsigned x)
-{
-    const unsigned intMax = static_cast<unsigned>(std::numeric_limits<int>::max());
-
-    if (x >= intMax)
-        return std::numeric_limits<int>::max();
-    return static_cast<int>(x);
-}
-
-inline bool isWithinIntRange(float x)
-{
-    return x > static_cast<float>(std::numeric_limits<int>::min()) && x < static_cast<float>(std::numeric_limits<int>::max());
-}
-
-template<typename T> inline bool hasOneBitSet(T value)
-{
-    return !((value - 1) & value) && value;
-}
-
-template<typename T> inline bool hasZeroOrOneBitsSet(T value)
-{
-    return !((value - 1) & value);
-}
-
-template<typename T> inline bool hasTwoOrMoreBitsSet(T value)
-{
-    return !hasZeroOrOneBitsSet(value);
-}
-
-template <typename T> inline unsigned getLSBSet(T value)
-{
-    unsigned result = 0;
-
-    while (value >>= 1)
-        ++result;
-
-    return result;
-}
-
-template<typename T> inline T timesThreePlusOneDividedByTwo(T value)
-{
-    // Mathematically equivalent to:
-    //   (value * 3 + 1) / 2;
-    // or:
-    //   (unsigned)ceil(value * 1.5));
-    // This form is not prone to internal overflow.
-    return value + (value >> 1) + (value & 1);
-}
-
-#ifndef UINT64_C
-#if COMPILER(MSVC)
-#define UINT64_C(c) c ## ui64
-#else
-#define UINT64_C(c) c ## ull
-#endif
-#endif
-
-#if COMPILER(MINGW64) && (!defined(__MINGW64_VERSION_RC) || __MINGW64_VERSION_RC < 1)
-inline double wtf_pow(double x, double y)
-{
-    // MinGW-w64 has a custom implementation for pow.
-    // This handles certain special cases that are different.
-    if ((x == 0.0 || std::isinf(x)) && std::isfinite(y)) {
-        double f;
-        if (modf(y, &f) != 0.0)
-            return ((x == 0.0) ^ (y > 0.0)) ? std::numeric_limits<double>::infinity() : 0.0;
-    }
-
-    if (x == 2.0) {
-        int yInt = static_cast<int>(y);
-        if (y == yInt)
-            return ldexp(1.0, yInt);
-    }
-
-    return pow(x, y);
-}
-#define pow(x, y) wtf_pow(x, y)
-#endif // COMPILER(MINGW64) && (!defined(__MINGW64_VERSION_RC) || __MINGW64_VERSION_RC < 1)
-
-
-// decompose 'number' to its sign, exponent, and mantissa components.
-// The result is interpreted as:
-//     (sign ? -1 : 1) * pow(2, exponent) * (mantissa / (1 << 52))
-inline void decomposeDouble(double number, bool& sign, int32_t& exponent, uint64_t& mantissa)
-{
-    ASSERT(std::isfinite(number));
-
-    sign = std::signbit(number);
-
-    uint64_t bits = WTF::bitwise_cast<uint64_t>(number);
-    exponent = (static_cast<int32_t>(bits >> 52) & 0x7ff) - 0x3ff;
-    mantissa = bits & 0xFFFFFFFFFFFFFull;
-
-    // Check for zero/denormal values; if so, adjust the exponent,
-    // if not insert the implicit, omitted leading 1 bit.
-    if (exponent == -0x3ff)
-        exponent = mantissa ? -0x3fe : 0;
-    else
-        mantissa |= 0x10000000000000ull;
-}
-
-// Calculate d % 2^{64}.
-inline void doubleToInteger(double d, unsigned long long& value)
-{
-    if (std::isnan(d) || std::isinf(d))
-        value = 0;
-    else {
-        // -2^{64} < fmodValue < 2^{64}.
-        double fmodValue = fmod(trunc(d), std::numeric_limits<unsigned long long>::max() + 1.0);
-        if (fmodValue >= 0) {
-            // 0 <= fmodValue < 2^{64}.
-            // 0 <= value < 2^{64}. This cast causes no loss.
-            value = static_cast<unsigned long long>(fmodValue);
-        } else {
-            // -2^{64} < fmodValue < 0.
-            // 0 < fmodValueInUnsignedLongLong < 2^{64}. This cast causes no loss.
-            unsigned long long fmodValueInUnsignedLongLong = static_cast<unsigned long long>(-fmodValue);
-            // -1 < (std::numeric_limits<unsigned long long>::max() - fmodValueInUnsignedLongLong) < 2^{64} - 1.
-            // 0 < value < 2^{64}.
-            value = std::numeric_limits<unsigned long long>::max() - fmodValueInUnsignedLongLong + 1;
-        }
-    }
-}
-
-namespace WTF {
-
-// From http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
-inline uint32_t roundUpToPowerOfTwo(uint32_t v)
-{
-    v--;
-    v |= v >> 1;
-    v |= v >> 2;
-    v |= v >> 4;
-    v |= v >> 8;
-    v |= v >> 16;
-    v++;
-    return v;
-}
-
-inline unsigned fastLog2(unsigned i)
-{
-    unsigned log2 = 0;
-    if (i & (i - 1))
-        log2 += 1;
-    if (i >> 16)
-        log2 += 16, i >>= 16;
-    if (i >> 8)
-        log2 += 8, i >>= 8;
-    if (i >> 4)
-        log2 += 4, i >>= 4;
-    if (i >> 2)
-        log2 += 2, i >>= 2;
-    if (i >> 1)
-        log2 += 1;
-    return log2;
-}
-
-} // namespace WTF
-
-#endif // #ifndef WTF_MathExtras_h