///////////////////////////////////////////////////////////////////////////

//

// Copyright (c) 2002-2012, Industrial Light & Magic, a division of Lucas

// Digital Ltd. LLC

// 

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

// *       Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

// *       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.

// *       Neither the name of Industrial Light & Magic nor the names of

// its contributors may be used to endorse or promote products derived

// from this software without specific prior written permission. 

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "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 THE COPYRIGHT

// OWNER 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 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