opencv/3rdparty/openexr/IlmImf/ImfConvert.cpp
2012-10-17 15:57:49 +04:00

140 lines
3.3 KiB
C++

///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2002, 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.
//
///////////////////////////////////////////////////////////////////////////
//-----------------------------------------------------------------------------
//
// Routines for converting between pixel data types,
// with well-defined behavior for exceptional cases.
//
//-----------------------------------------------------------------------------
#include <ImfConvert.h>
#include <limits.h>
namespace Imf {
namespace {
inline bool
isNegative (float f)
{
union {float f; int i;} u;
u.f = f;
return (u.i & 0x80000000) != 0;
}
inline bool
isNan (float f)
{
union {float f; int i;} u;
u.f = f;
return (u.i & 0x7fffffff) > 0x7f800000;
}
inline bool
isInfinity (float f)
{
union {float f; int i;} u;
u.f = f;
return (u.i & 0x7fffffff) == 0x7f800000;
}
inline bool
isFinite (float f)
{
union {float f; int i;} u;
u.f = f;
return (u.i & 0x7f800000) != 0x7f800000;
}
} // namespace
unsigned int
halfToUint (half h)
{
if (h.isNegative() || h.isNan())
return 0;
if (h.isInfinity())
return UINT_MAX;
return (unsigned int) h;
}
unsigned int
floatToUint (float f)
{
if (isNegative (f) || isNan (f))
return 0;
if (isInfinity (f) || f > UINT_MAX)
return UINT_MAX;
return (unsigned int) f;
}
half
uintToHalf (unsigned int ui)
{
if (ui > HALF_MAX)
return half::posInf();
return half (ui);
}
half
floatToHalf (float f)
{
if (isFinite (f))
{
if (f > HALF_MAX)
return half::posInf();
if (f < -HALF_MAX)
return half::negInf();
}
return half (f);
}
} // namespace Imf