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///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2002-2012, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
//
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are
// met:
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///////////////////////////////////////////////////////////////////////////
#ifndef INCLUDED_IMATHFUN_H
#define INCLUDED_IMATHFUN_H
//-----------------------------------------------------------------------------
//
// Miscellaneous utility functions
//
//-----------------------------------------------------------------------------
#include "ImathExport.h"
#include "ImathLimits.h"
#include "ImathInt64.h"
#include "ImathNamespace.h"
IMATH_INTERNAL_NAMESPACE_HEADER_ENTER
template <class T>
inline T
abs (T a)
{
return (a > T(0)) ? a : -a;
}
template <class T>
inline int
sign (T a)
{
return (a > T(0))? 1 : ((a < T(0)) ? -1 : 0);
}
template <class T, class Q>
inline T
lerp (T a, T b, Q t)
{
return (T) (a * (1 - t) + b * t);
}
template <class T, class Q>
inline T
ulerp (T a, T b, Q t)
{
return (T) ((a > b)? (a - (a - b) * t): (a + (b - a) * t));
}
template <class T>
inline T
lerpfactor(T m, T a, T b)
{
//
// Return how far m is between a and b, that is return t such that
// if:
// t = lerpfactor(m, a, b);
// then:
// m = lerp(a, b, t);
//
// If a==b, return 0.
//
T d = b - a;
T n = m - a;
if (abs(d) > T(1) || abs(n) < limits<T>::max() * abs(d))
return n / d;
return T(0);
}
template <class T>
inline T
clamp (T a, T l, T h)
{
return (a < l)? l : ((a > h)? h : a);
}
template <class T>
inline int
cmp (T a, T b)
{
return IMATH_INTERNAL_NAMESPACE::sign (a - b);
}
template <class T>
inline int
cmpt (T a, T b, T t)
{
return (IMATH_INTERNAL_NAMESPACE::abs (a - b) <= t)? 0 : cmp (a, b);
}
template <class T>
inline bool
iszero (T a, T t)
{
return (IMATH_INTERNAL_NAMESPACE::abs (a) <= t) ? 1 : 0;
}
template <class T1, class T2, class T3>
inline bool
equal (T1 a, T2 b, T3 t)
{
return IMATH_INTERNAL_NAMESPACE::abs (a - b) <= t;
}
template <class T>
inline int
floor (T x)
{
return (x >= 0)? int (x): -(int (-x) + (-x > int (-x)));
}
template <class T>
inline int
ceil (T x)
{
return -floor (-x);
}
template <class T>
inline int
trunc (T x)
{
return (x >= 0) ? int(x) : -int(-x);
}
//
// Integer division and remainder where the
// remainder of x/y has the same sign as x:
//
// divs(x,y) == (abs(x) / abs(y)) * (sign(x) * sign(y))
// mods(x,y) == x - y * divs(x,y)
//
inline int
divs (int x, int y)
{
return (x >= 0)? ((y >= 0)? ( x / y): -( x / -y)):
((y >= 0)? -(-x / y): (-x / -y));
}
inline int
mods (int x, int y)
{
return (x >= 0)? ((y >= 0)? ( x % y): ( x % -y)):
((y >= 0)? -(-x % y): -(-x % -y));
}
//
// Integer division and remainder where the
// remainder of x/y is always positive:
//
// divp(x,y) == floor (double(x) / double (y))
// modp(x,y) == x - y * divp(x,y)
//
inline int
divp (int x, int y)
{
return (x >= 0)? ((y >= 0)? ( x / y): -( x / -y)):
((y >= 0)? -((y-1-x) / y): ((-y-1-x) / -y));
}
inline int
modp (int x, int y)
{
return x - y * divp (x, y);
}
//----------------------------------------------------------
// Successor and predecessor for floating-point numbers:
//
// succf(f) returns float(f+e), where e is the smallest
// positive number such that float(f+e) != f.
//
// predf(f) returns float(f-e), where e is the smallest
// positive number such that float(f-e) != f.
//
// succd(d) returns double(d+e), where e is the smallest
// positive number such that double(d+e) != d.
//
// predd(d) returns double(d-e), where e is the smallest
// positive number such that double(d-e) != d.
//
// Exceptions: If the input value is an infinity or a nan,
// succf(), predf(), succd(), and predd() all
// return the input value without changing it.
//
//----------------------------------------------------------
IMATH_EXPORT float succf (float f);
IMATH_EXPORT float predf (float f);
IMATH_EXPORT double succd (double d);
IMATH_EXPORT double predd (double d);
//
// Return true if the number is not a NaN or Infinity.
//
inline bool
finitef (float f)
{
union {float f; int i;} u;
u.f = f;
return (u.i & 0x7f800000) != 0x7f800000;
}
inline bool
finited (double d)
{
union {double d; Int64 i;} u;
u.d = d;
return (u.i & 0x7ff0000000000000LL) != 0x7ff0000000000000LL;
}
IMATH_INTERNAL_NAMESPACE_HEADER_EXIT
#endif // INCLUDED_IMATHFUN_H
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