/*
 * Mesa 3-D graphics library
 * Version:  6.5.2
 *
 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


#ifndef P_UTIL_H
#define P_UTIL_H

#include "p_compiler.h"

#define CALLOC_STRUCT(T)   (struct T *) calloc(1, sizeof(struct T))



/** Clamp X to [MIN,MAX] */
#define CLAMP( X, MIN, MAX )  ( (X)<(MIN) ? (MIN) : ((X)>(MAX) ? (MAX) : (X)) )

/** Assign X to CLAMP(X, MIN, MAX) */
#define CLAMP_SELF(x, mn, mx)  \
   ( (x)<(mn) ? ((x) = (mn)) : ((x)>(mx) ? ((x)=(mx)) : (x)) )

/** Minimum of two values: */
#define MIN2( A, B )   ( (A)<(B) ? (A) : (B) )

/** Maximum of two values: */
#define MAX2( A, B )   ( (A)>(B) ? (A) : (B) )


#define Elements(x) sizeof(x)/sizeof(*(x))

union fi {
   float f;
   int i;
   unsigned ui;
};

#define UBYTE_TO_FLOAT( ub ) ((float)(ub) / 255.0F)

#define IEEE_0996 0x3f7f0000	/* 0.996 or so */

/* This function/macro is sensitive to precision.  Test very carefully
 * if you change it!
 */
#define UNCLAMPED_FLOAT_TO_UBYTE(UB, F)					\
        do {								\
           union fi __tmp;						\
           __tmp.f = (F);						\
           if (__tmp.i < 0)						\
              UB = (ubyte) 0;						\
           else if (__tmp.i >= IEEE_0996)				\
              UB = (ubyte) 255;					\
           else {							\
              __tmp.f = __tmp.f * (255.0F/256.0F) + 32768.0F;		\
              UB = (ubyte) __tmp.i;					\
           }								\
        } while (0)



static INLINE unsigned pack_ub4( unsigned char b0,
				 unsigned char b1,
				 unsigned char b2,
				 unsigned char b3 )
{
   return ((((unsigned int)b0) << 0) |
	   (((unsigned int)b1) << 8) |
	   (((unsigned int)b2) << 16) |
	   (((unsigned int)b3) << 24));
}

static INLINE unsigned fui( float f )
{
   union fi fi;
   fi.f = f;
   return fi.ui;
}

static INLINE unsigned char float_to_ubyte( float f )
{
   unsigned char ub;
   UNCLAMPED_FLOAT_TO_UBYTE(ub, f);
   return ub;
}

static INLINE unsigned pack_ui32_float4( float a,
					 float b, 
					 float d, 
					 float c )
{
   return pack_ub4( float_to_ubyte(a),
		    float_to_ubyte(b),
		    float_to_ubyte(c),
		    float_to_ubyte(d) );
}

#endif