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

//

// 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.

//

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

#include "ImathFun.h"

IMATH_INTERNAL_NAMESPACE_SOURCE_ENTER

float

succf (float f)

{

    union {float f; int i;} u;

    u.f = f;

    if ((u.i & 0x7f800000) == 0x7f800000)

    {

        // Nan or infinity; don't change value.

    }

    else if (u.i == 0x00000000 || u.i == 0x80000000)

    {

        // Plus or minus zero.

        u.i = 0x00000001;

    }

    else if (u.i > 0)

    {

        // Positive float, normalized or denormalized.

        // Incrementing the largest positive float

        // produces +infinity.

        ++u.i;

    }

    else

    {

        // Negative normalized or denormalized float.

        --u.i;

    }

    return u.f;

}

float

predf (float f)

{

    union {float f; int i;} u;

    u.f = f;

    if ((u.i & 0x7f800000) == 0x7f800000)

    {

        // Nan or infinity; don't change value.

    }

    else if (u.i == 0x00000000 || u.i == 0x80000000)

    {

        // Plus or minus zero.

        u.i = 0x80000001;

    }

    else if (u.i > 0)

    {

        // Positive float, normalized or denormalized.

        --u.i;

    }

    else

    {

        // Negative normalized or denormalized float.

        // Decrementing the largest negative float

        // produces -infinity.

        ++u.i;

    }

    return u.f;

}

double

succd (double d)

{

    union {double d; Int64 i;} u;

    u.d = d;

    if ((u.i & 0x7ff0000000000000LL) == 0x7ff0000000000000LL)

    {

        // Nan or infinity; don't change value.

    }

    else if (u.i == 0x0000000000000000LL || u.i == 0x8000000000000000LL)

    {

        // Plus or minus zero.

        u.i = 0x0000000000000001LL;

    }

    else if (u.d > 0)

    {

        // Positive double, normalized or denormalized.

        // Incrementing the largest positive double

        // produces +infinity.

        ++u.i;

    }

    else

    {

        // Negative normalized or denormalized double.

        --u.i;

    }

    return u.d;

}

double

predd (double d)

{

    union {double d; Int64 i;} u;

    u.d = d;

    if ((u.i & 0x7ff0000000000000LL) == 0x7ff0000000000000LL)

    {

        // Nan or infinity; don't change value.

    }

    else if (u.i == 0x0000000000000000LL || u.i == 0x8000000000000000LL)

    {

        // Plus or minus zero.

        u.i = 0x8000000000000001LL;

    }

    else if (u.d > 0)

    {

        // Positive double, normalized or denormalized.

        --u.i;

    }

    else

    {

        // Negative normalized or denormalized double.

        // Decrementing the largest negative double

        // produces -infinity.

        ++u.i;

    }

    return u.d;

}

IMATH_INTERNAL_NAMESPACE_SOURCE_EXIT