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+/// Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+///
+/// Developed at SunPro, a Sun Microsystems, Inc. business.
+/// Permission to use, copy, modify, and distribute this
+/// software is freely granted, provided that this notice
+/// is preserved.
+
+#include "../detail/type_float.hpp"
+#include "../ext/scalar_constants.hpp"
+#include <cmath>
+#include <cfloat>
+
+#if(GLM_COMPILER & GLM_COMPILER_VC)
+# pragma warning(push)
+# pragma warning(disable : 4127)
+#endif
+
+typedef union
+{
+ float value;
+ /* FIXME: Assumes 32 bit int. */
+ unsigned int word;
+} ieee_float_shape_type;
+
+typedef union
+{
+ double value;
+ struct
+ {
+ int lsw;
+ int msw;
+ } parts;
+} ieee_double_shape_type;
+
+#define GLM_EXTRACT_WORDS(ix0,ix1,d) \
+ do { \
+ ieee_double_shape_type ew_u; \
+ ew_u.value = (d); \
+ (ix0) = ew_u.parts.msw; \
+ (ix1) = ew_u.parts.lsw; \
+ } while (0)
+
+#define GLM_GET_FLOAT_WORD(i,d) \
+ do { \
+ ieee_float_shape_type gf_u; \
+ gf_u.value = (d); \
+ (i) = gf_u.word; \
+ } while (0)
+
+#define GLM_SET_FLOAT_WORD(d,i) \
+ do { \
+ ieee_float_shape_type sf_u; \
+ sf_u.word = (i); \
+ (d) = sf_u.value; \
+ } while (0)
+
+#define GLM_INSERT_WORDS(d,ix0,ix1) \
+ do { \
+ ieee_double_shape_type iw_u; \
+ iw_u.parts.msw = (ix0); \
+ iw_u.parts.lsw = (ix1); \
+ (d) = iw_u.value; \
+ } while (0)
+
+namespace glm{
+namespace detail
+{
+ GLM_FUNC_QUALIFIER float nextafterf(float x, float y)
+ {
+ volatile float t;
+ int hx, hy, ix, iy;
+
+ GLM_GET_FLOAT_WORD(hx, x);
+ GLM_GET_FLOAT_WORD(hy, y);
+ ix = hx & 0x7fffffff; // |x|
+ iy = hy & 0x7fffffff; // |y|
+
+ if((ix > 0x7f800000) || // x is nan
+ (iy > 0x7f800000)) // y is nan
+ return x + y;
+ if(abs(y - x) <= epsilon<float>())
+ return y; // x=y, return y
+ if(ix == 0)
+ { // x == 0
+ GLM_SET_FLOAT_WORD(x, (hy & 0x80000000) | 1);// return +-minsubnormal
+ t = x * x;
+ if(abs(t - x) <= epsilon<float>())
+ return t;
+ else
+ return x; // raise underflow flag
+ }
+ if(hx >= 0)
+ { // x > 0
+ if(hx > hy) // x > y, x -= ulp
+ hx -= 1;
+ else // x < y, x += ulp
+ hx += 1;
+ }
+ else
+ { // x < 0
+ if(hy >= 0 || hx > hy) // x < y, x -= ulp
+ hx -= 1;
+ else // x > y, x += ulp
+ hx += 1;
+ }
+ hy = hx & 0x7f800000;
+ if(hy >= 0x7f800000)
+ return x + x; // overflow
+ if(hy < 0x00800000) // underflow
+ {
+ t = x * x;
+ if(abs(t - x) > epsilon<float>())
+ { // raise underflow flag
+ GLM_SET_FLOAT_WORD(y, hx);
+ return y;
+ }
+ }
+ GLM_SET_FLOAT_WORD(x, hx);
+ return x;
+ }
+
+ GLM_FUNC_QUALIFIER double nextafter(double x, double y)
+ {
+ volatile double t;
+ int hx, hy, ix, iy;
+ unsigned int lx, ly;
+
+ GLM_EXTRACT_WORDS(hx, lx, x);
+ GLM_EXTRACT_WORDS(hy, ly, y);
+ ix = hx & 0x7fffffff; // |x|
+ iy = hy & 0x7fffffff; // |y|
+
+ if(((ix >= 0x7ff00000) && ((ix - 0x7ff00000) | lx) != 0) || // x is nan
+ ((iy >= 0x7ff00000) && ((iy - 0x7ff00000) | ly) != 0)) // y is nan
+ return x + y;
+ if(abs(y - x) <= epsilon<double>())
+ return y; // x=y, return y
+ if((ix | lx) == 0)
+ { // x == 0
+ GLM_INSERT_WORDS(x, hy & 0x80000000, 1); // return +-minsubnormal
+ t = x * x;
+ if(abs(t - x) <= epsilon<double>())
+ return t;
+ else
+ return x; // raise underflow flag
+ }
+ if(hx >= 0) { // x > 0
+ if(hx > hy || ((hx == hy) && (lx > ly))) { // x > y, x -= ulp
+ if(lx == 0) hx -= 1;
+ lx -= 1;
+ }
+ else { // x < y, x += ulp
+ lx += 1;
+ if(lx == 0) hx += 1;
+ }
+ }
+ else { // x < 0
+ if(hy >= 0 || hx > hy || ((hx == hy) && (lx > ly))){// x < y, x -= ulp
+ if(lx == 0) hx -= 1;
+ lx -= 1;
+ }
+ else { // x > y, x += ulp
+ lx += 1;
+ if(lx == 0) hx += 1;
+ }
+ }
+ hy = hx & 0x7ff00000;
+ if(hy >= 0x7ff00000)
+ return x + x; // overflow
+ if(hy < 0x00100000)
+ { // underflow
+ t = x * x;
+ if(abs(t - x) > epsilon<double>())
+ { // raise underflow flag
+ GLM_INSERT_WORDS(y, hx, lx);
+ return y;
+ }
+ }
+ GLM_INSERT_WORDS(x, hx, lx);
+ return x;
+ }
+}//namespace detail
+}//namespace glm
+
+#if(GLM_COMPILER & GLM_COMPILER_VC)
+# pragma warning(pop)
+#endif
+
+namespace glm
+{
+ template<>
+ GLM_FUNC_QUALIFIER float nextFloat(float x)
+ {
+# if GLM_HAS_CXX11_STL
+ return std::nextafter(x, std::numeric_limits<float>::max());
+# elif((GLM_COMPILER & GLM_COMPILER_VC) || ((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_PLATFORM & GLM_PLATFORM_WINDOWS)))
+ return detail::nextafterf(x, FLT_MAX);
+# elif(GLM_PLATFORM & GLM_PLATFORM_ANDROID)
+ return __builtin_nextafterf(x, FLT_MAX);
+# else
+ return nextafterf(x, FLT_MAX);
+# endif
+ }
+
+ template<>
+ GLM_FUNC_QUALIFIER double nextFloat(double x)
+ {
+# if GLM_HAS_CXX11_STL
+ return std::nextafter(x, std::numeric_limits<double>::max());
+# elif((GLM_COMPILER & GLM_COMPILER_VC) || ((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_PLATFORM & GLM_PLATFORM_WINDOWS)))
+ return detail::nextafter(x, std::numeric_limits<double>::max());
+# elif(GLM_PLATFORM & GLM_PLATFORM_ANDROID)
+ return __builtin_nextafter(x, DBL_MAX);
+# else
+ return nextafter(x, DBL_MAX);
+# endif
+ }
+
+ template<typename T>
+ GLM_FUNC_QUALIFIER T nextFloat(T x, int ULPs)
+ {
+ GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'next_float' only accept floating-point input");
+ assert(ULPs >= 0);
+
+ T temp = x;
+ for(int i = 0; i < ULPs; ++i)
+ temp = nextFloat(temp);
+ return temp;
+ }
+
+ GLM_FUNC_QUALIFIER float prevFloat(float x)
+ {
+# if GLM_HAS_CXX11_STL
+ return std::nextafter(x, std::numeric_limits<float>::min());
+# elif((GLM_COMPILER & GLM_COMPILER_VC) || ((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_PLATFORM & GLM_PLATFORM_WINDOWS)))
+ return detail::nextafterf(x, FLT_MIN);
+# elif(GLM_PLATFORM & GLM_PLATFORM_ANDROID)
+ return __builtin_nextafterf(x, FLT_MIN);
+# else
+ return nextafterf(x, FLT_MIN);
+# endif
+ }
+
+ GLM_FUNC_QUALIFIER double prevFloat(double x)
+ {
+# if GLM_HAS_CXX11_STL
+ return std::nextafter(x, std::numeric_limits<double>::min());
+# elif((GLM_COMPILER & GLM_COMPILER_VC) || ((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_PLATFORM & GLM_PLATFORM_WINDOWS)))
+ return _nextafter(x, DBL_MIN);
+# elif(GLM_PLATFORM & GLM_PLATFORM_ANDROID)
+ return __builtin_nextafter(x, DBL_MIN);
+# else
+ return nextafter(x, DBL_MIN);
+# endif
+ }
+
+ template<typename T>
+ GLM_FUNC_QUALIFIER T prevFloat(T x, int ULPs)
+ {
+ GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'prev_float' only accept floating-point input");
+ assert(ULPs >= 0);
+
+ T temp = x;
+ for(int i = 0; i < ULPs; ++i)
+ temp = prevFloat(temp);
+ return temp;
+ }
+
+ GLM_FUNC_QUALIFIER int floatDistance(float x, float y)
+ {
+ detail::float_t<float> const a(x);
+ detail::float_t<float> const b(y);
+
+ return abs(a.i - b.i);
+ }
+
+ GLM_FUNC_QUALIFIER int64 floatDistance(double x, double y)
+ {
+ detail::float_t<double> const a(x);
+ detail::float_t<double> const b(y);
+
+ return abs(a.i - b.i);
+ }
+}//namespace glm
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