Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

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diff --git a/Source/JavaScriptCore/wtf/MathExtras.h b/Source/JavaScriptCore/wtf/MathExtras.h
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+/*
+ * 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 COMPILER(MSVC)
+#if OS(WINCE)
+#include <stdlib.h>
+#endif
+#include <limits>
+#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)
+
+#ifndef isfinite
+inline bool isfinite(double x) { return finite(x) && !isnand(x); }
+#endif
+#ifndef isinf
+inline bool isinf(double x) { return !finite(x) && !isnand(x); }
+#endif
+#ifndef signbit
+inline bool signbit(double x) { return copysign(1.0, x) < 0; }
+#endif
+
+#endif
+
+#if OS(OPENBSD)
+
+#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
+
+#endif
+
+#if COMPILER(MSVC) || (COMPILER(RVCT) && !(RVCT_VERSION_AT_LEAST(3, 0, 0, 0)))
+
+// 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 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
+
+inline bool isinf(double num) { return !_finite(num) && !_isnan(num); }
+inline bool isnan(double num) { return !!_isnan(num); }
+inline bool signbit(double num) { return _copysign(1.0, num) < 0; }
+
+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); }
+inline int isfinite(double x) { return _finite(x); }
+
+// 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.
+    return log(num) / 0.693147180559945309417232121458176568;
+}
+
+inline float log2f(float num)
+{
+    // This constant is roughly M_LN2, which is not provided by default on Windows.
+    return logf(num) / 0.693147180559945309417232121458176568f;
+}
+
+// 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 (!isinf(x) && 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)
+
+#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());
+}
+
+#if !COMPILER(MSVC) && !COMPILER(RVCT) && !OS(SOLARIS)
+using std::isfinite;
+using std::isinf;
+using std::isnan;
+using std::signbit;
+#endif
+
+// 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(isfinite(number));
+
+    sign = 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 (isnan(d) || 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;
+        }
+    }
+}
+
+#endif // #ifndef WTF_MathExtras_h