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

//

// Copyright (c) 2009, 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_IMF_CHECKED_ARITHMETIC_H

#define INCLUDED_IMF_CHECKED_ARITHMETIC_H

//-----------------------------------------------------------------------------

//

//	Integer arithmetic operations that throw exceptions

//      on overflow, underflow or division by zero.

//

//-----------------------------------------------------------------------------

#include <limits>

#include "IexMathExc.h"

#include "ImfNamespace.h"

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER

template <bool b> struct StaticAssertionFailed;

template <> struct StaticAssertionFailed <true> {};

#define IMF_STATIC_ASSERT(x) \

    do {StaticAssertionFailed <x> staticAssertionFailed; ((void) staticAssertionFailed);} while (false)

template <class T>

T

uiMult (T a, T b)

{

    //

    // Unsigned integer multiplication

    //

    IMF_STATIC_ASSERT (!std::numeric_limits<T>::is_signed &&

                        std::numeric_limits<T>::is_integer);

    if (a > 0 && b > std::numeric_limits<T>::max() / a)

        throw IEX_NAMESPACE::OverflowExc ("Integer multiplication overflow.");

    return a * b;

}

template <class T>

T

uiDiv (T a, T b)

{

    //

    // Unsigned integer division

    //

    IMF_STATIC_ASSERT (!std::numeric_limits<T>::is_signed &&

                        std::numeric_limits<T>::is_integer);

    if (b == 0)

        throw IEX_NAMESPACE::DivzeroExc ("Integer division by zero.");

    return a / b;

}

template <class T>

T

uiAdd (T a, T b)

{

    //

    // Unsigned integer addition

    //

    IMF_STATIC_ASSERT (!std::numeric_limits<T>::is_signed &&

                        std::numeric_limits<T>::is_integer);

    if (a > std::numeric_limits<T>::max() - b)

        throw IEX_NAMESPACE::OverflowExc ("Integer addition overflow.");

    return a + b;

}

template <class T>

T

uiSub (T a, T b)

{

    //

    // Unsigned integer subtraction

    //

    IMF_STATIC_ASSERT (!std::numeric_limits<T>::is_signed &&

                        std::numeric_limits<T>::is_integer);

    if (a < b)

        throw IEX_NAMESPACE::UnderflowExc ("Integer subtraction underflow.");

    return a - b;

}

template <class T>

size_t

checkArraySize (T n, size_t s)

{

    //

    // Verify that the size, in bytes, of an array with n elements

    // of size s can be computed without overflowing:

    //

    // If computing

    //

    //      size_t (n) * s

    //

    // would overflow, then throw an IEX_NAMESPACE::OverflowExc exception.

    // Otherwise return

    //

    //      size_t (n).

    //

    IMF_STATIC_ASSERT (!std::numeric_limits<T>::is_signed &&

                        std::numeric_limits<T>::is_integer);

    IMF_STATIC_ASSERT (sizeof (T) <= sizeof (size_t));

    if (size_t (n) > std::numeric_limits<size_t>::max() / s)

        throw IEX_NAMESPACE::OverflowExc ("Integer multiplication overflow.");

    return size_t (n);

}

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT

#endif