Brooklyn/userland/interface/khronos/common/khrn_int_util_cr.h

/*
Copyright (c) 2012, Broadcom Europe Ltd
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 the copyright holder 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 HOLDER 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.
*/

static INLINE bool clean_boolean(int b)
{
   return !!b;
}

/*
   clean_float(float f)

   Implementation notes:

   'Cleans' a floating point number by converting -INF to -FLT_MAX, INF to FLT_MAX and
   any NaN to zero. Khronos spec says nothing about what happens if an unclean float is
   passed to a function, so this at least guarantees reasonable behaviour.

   Preconditions:

   -

   Postconditions:

   result r is not NaN or infinite
*/

static INLINE float clean_float(float f)
{
   uint32_t u = float_to_bits(f);

   if (u == 0x7f800000)
      return FLT_MAX;
   if (u == (uint32_t)0xff800000)
      return -FLT_MAX;
   if ((u & 0x7f800000) == 0x7f800000)
      return 0;                              // force NaN to zero

   return f;
}

/*
   clampf(float x, float l, float u)

   Implementation notes:

   Khronos makes frequent use of the datatype clampf, which is defined as

      floating-point value clamped to [0, 1]

   This function is used in many places to clamp a floating point value to lie in a range
   (almost always 0..1) and also to implicitly remove any NaNs or infinities.

   Preconditions:

   l and u are not NaN or infinity and l <= u

   Postconditions:

   result r is not NaN or an infinity, and l <= r <= u
*/

static INLINE float clampf(float x, float l, float u)
{
   vcos_assert(l <= u);

   x = clean_float(x);

   return _maxf(_minf(x, u), l);
}

/*
   fixed_to_float(int f)

   Implementation notes:

   OpenGL ES 1.1 makes use of the datatype 'fixed' which is defined as a:

      signed 2s complement 16.16 scaled integer

   This function is used to convert a fixed value to its floating point equivalent, with
   some loss of precision. We believe this is justified as the state tables in the spec
   talk about storing all these values as type R (floating-point number).

   Preconditions:

   -

   Postconditions:

   result r is not NaN or an infinity
*/

static INLINE float fixed_to_float(int f)
{
   return (float)f / 65536.0f;
}

/*
   clampi(int x, int l, int u)

   Implementation notes:

   Preconditions:

   l <= u

   Postconditions:

   result r satisfies l <= r <= u
*/

static INLINE int clampi(int x, int l, int u)
{
   vcos_assert(l <= u);

   return (int) _max(_min( (int32_t)x, (int32_t)u), (int32_t)l);
}