jas_fix.h

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/*
 * Copyright (c) 1999-2000 Image Power, Inc. and the University of
 *   British Columbia.
 * Copyright (c) 2001-2002 Michael David Adams.
 * All rights reserved.
 */
 
/* __START_OF_JASPER_LICENSE__
 * 
 * JasPer License Version 2.0
 * 
 * Copyright (c) 2001-2006 Michael David Adams
 * Copyright (c) 1999-2000 Image Power, Inc.
 * Copyright (c) 1999-2000 The University of British Columbia
 * 
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person (the
 * "User") 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, 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:
 * 
 * 1.  The above copyright notices and this permission notice (which
 * includes the disclaimer below) shall be included in all copies or
 * substantial portions of the Software.
 * 
 * 2.  The name of a copyright holder shall not be used to endorse or
 * promote products derived from the Software without specific prior
 * written permission.
 * 
 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
 * LICENSE.  NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
 * THIS DISCLAIMER.  THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
 * "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 OF THIRD PARTY RIGHTS.  IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  NO ASSURANCES ARE
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 * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY.  THE SOFTWARE
 * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
 * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
 * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
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 * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
 * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
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 * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
 * 
 * __END_OF_JASPER_LICENSE__
 */
 
#ifndef JAS_FIX_H
#define JAS_FIX_H
 
/******************************************************************************\
* Includes.
\******************************************************************************/
 
/* The configuration header file should be included first. */
#include <jasper/jas_config.h> /* IWYU pragma: keep */
 
#include <jasper/jas_types.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
/******************************************************************************\
* Types.
\******************************************************************************/
 
#if defined(JAS_ENABLE_32BIT)
typedef int_least32_t jas_fix_t;
#define PRIjas_fix PRIiLEAST32
#else
typedef int_least64_t jas_fix_t;
#define PRIjas_fix PRIiLEAST64
#endif
 
/*
Integral type used for double-precision fixed-point representations.
*/
#if defined(JAS_ENABLE_32BIT)
typedef int_least64_t jas_fix_big_t;
#else
#if defined(JAS_HAVE_INT128_T)
typedef __int128_t jas_fix_big_t;
#else
typedef int_least64_t jas_fix_big_t;
#endif
#endif
 
/******************************************************************************\
* Constants.
\******************************************************************************/
 
#define JAS_FIX_ZERO(fix_t, fracbits) \
        JAS_INTTOFIX(fix_t, fracbits, 0)
 
#define JAS_FIX_ONE(fix_t, fracbits) \
        JAS_INTTOFIX(fix_t, fracbits, 1)
 
#define JAS_FIX_HALF(fix_t, fracbits) \
        (JAS_CAST(fix_t, 1) << ((fracbits) - 1))
 
/******************************************************************************\
* Conversion operations.
\******************************************************************************/
 
#define JAS_INTTOFIX(fix_t, fracbits, x) \
        (JAS_CAST(fix_t, x) << (fracbits))
 
#define JAS_FIXTOINT(fix_t, fracbits, x) \
        JAS_CAST(int, (x) >> (fracbits))
 
#define JAS_FIXTODBL(fix_t, fracbits, x) \
        (JAS_CAST(double, x) / JAS_FIX_ONE(fix_t, fracbits))
 
#define JAS_DBLTOFIX(fix_t, fracbits, x) \
        JAS_CAST(fix_t, ((x) * JAS_CAST(double, JAS_FIX_ONE(fix_t, fracbits))))
 
/******************************************************************************\
* Basic arithmetic operations.
* All other arithmetic operations are synthesized from these basic operations.
* There are three macros for each type of arithmetic operation.
* One macro always performs overflow/underflow checking, one never performs
* overflow/underflow checking, and one is generic with its behavior
* depending on compile-time flags.
* Only the generic macros should be invoked directly by application code.
\******************************************************************************/
 
#if !defined(DEBUG_OVERFLOW)
#define JAS_FIX_ADD                     JAS_FIX_ADD_FAST
#else
#define JAS_FIX_ADD                     JAS_FIX_ADD_OFLOW
#endif
 
#define JAS_FIX_ADD_FAST(fix_t, fracbits, x, y) ((x) + (y))
 
#define JAS_FIX_ADD_OFLOW(fix_t, fracbits, x, y) \
        ((x) >= 0) ? \
          (((y) >= 0) ? ((x) + (y) >= 0 || JAS_FIX_OFLOW(), (x) + (y)) : \
          ((x) + (y))) : \
          (((y) >= 0) ? ((x) + (y)) : ((x) + (y) < 0 || JAS_FIX_OFLOW(), \
          (x) + (y)))
 
#if !defined(DEBUG_OVERFLOW)
#define JAS_FIX_MUL                     JAS_FIX_MUL_FAST
#else
#define JAS_FIX_MUL                     JAS_FIX_MUL_OFLOW
#endif
 
#define JAS_FIX_MUL_FAST(fix_t, fracbits, bigfix_t, x, y) \
        JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y)) >> \
          (fracbits))
 
#define JAS_FIX_MUL_OFLOW(fix_t, fracbits, bigfix_t, x, y) \
        ((JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> (fracbits)) == \
          JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> \
          (fracbits))) ? \
          JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> \
          (fracbits))) : JAS_FIX_OFLOW())
 
#if !defined(DEBUG_OVERFLOW)
#define JAS_FIX_MULBYINT        JAS_FIX_MULBYINT_FAST
#else
#define JAS_FIX_MULBYINT        JAS_FIX_MULBYINT_OFLOW
#endif
 
#define JAS_FIX_MULBYINT_FAST(fix_t, fracbits, x, y) \
        JAS_CAST(fix_t, ((x) * (y)))
 
#define JAS_FIX_MULBYINT_OFLOW(fix_t, fracbits, x, y) \
        JAS_FIX_MULBYINT_FAST(fix_t, fracbits, x, y)
 
#if !defined(DEBUG_OVERFLOW)
#define JAS_FIX_DIV                     JAS_FIX_DIV_FAST
#else
#define JAS_FIX_DIV                     JAS_FIX_DIV_UFLOW
#endif
 
#define JAS_FIX_DIV_FAST(fix_t, fracbits, bigfix_t, x, y) \
        JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) << (fracbits)) / (y))
 
#define JAS_FIX_DIV_UFLOW(fix_t, fracbits, bigfix_t, x, y) \
        JAS_FIX_DIV_FAST(fix_t, fracbits, bigfix_t, x, y)
 
#if !defined(DEBUG_OVERFLOW)
#define JAS_FIX_NEG                     JAS_FIX_NEG_FAST
#else
#define JAS_FIX_NEG                     JAS_FIX_NEG_OFLOW
#endif
 
#define JAS_FIX_NEG_FAST(fix_t, fracbits, x) \
        (-(x))
 
/* Yes, overflow is actually possible for two's complement representations,
  although highly unlikely to occur. */
#define JAS_FIX_NEG_OFLOW(fix_t, fracbits, x) \
        (((x) < 0) ? (-(x) > 0 || JAS_FIX_OFLOW(), -(x)) : (-(x)))
 
#if !defined(DEBUG_OVERFLOW)
#define JAS_FIX_ASL                     JAS_FIX_ASL_FAST
#else
#define JAS_FIX_ASL                     JAS_FIX_ASL_OFLOW
#endif
 
#define JAS_FIX_ASL_FAST(fix_t, fracbits, x, n) \
        ((x) << (n))
 
#define JAS_FIX_ASL_OFLOW(fix_t, fracbits, x, n) \
        ((((x) << (n)) >> (n)) == (x) || JAS_FIX_OFLOW(), (x) << (n))
 
#if !defined(DEBUG_OVERFLOW)
#define JAS_FIX_ASR                     JAS_FIX_ASR_FAST
#else
#define JAS_FIX_ASR                     JAS_FIX_ASR_UFLOW
#endif
 
#define JAS_FIX_ASR_FAST(fix_t, fracbits, x, n) \
        ((x) >> (n))
 
#define JAS_FIX_ASR_UFLOW(fix_t, fracbits, x, n) \
        JAS_FIX_ASR_FAST(fix_t, fracbits, x, n)
 
/******************************************************************************\
* Other basic arithmetic operations.
\******************************************************************************/
 
#define JAS_FIX_SUB(fix_t, fracbits, x, y) \
        JAS_FIX_ADD(fix_t, fracbits, x, JAS_FIX_NEG(fix_t, fracbits, y))
 
#define JAS_FIX_PLUSEQ(fix_t, fracbits, x, y) \
        ((x) = JAS_FIX_ADD(fix_t, fracbits, x, y))
 
#define JAS_FIX_MINUSEQ(fix_t, fracbits, x, y) \
        ((x) = JAS_FIX_SUB(fix_t, fracbits, x, y))
 
#define JAS_FIX_MULEQ(fix_t, fracbits, bigfix_t, x, y) \
        ((x) = JAS_FIX_MUL(fix_t, fracbits, bigfix_t, x, y))
 
/******************************************************************************\
* Miscellaneous operations.
\******************************************************************************/
 
#define JAS_FIX_ABS(fix_t, fracbits, x) \
        (((x) >= 0) ? (x) : (JAS_FIX_NEG(fix_t, fracbits, x)))
 
#define JAS_FIX_ISINT(fix_t, fracbits, x) \
        (JAS_FIX_FLOOR(fix_t, fracbits, x) == (x))
 
#define JAS_FIX_SGN(fix_t, fracbits, x) \
        ((x) >= 0 ? 1 : (-1))
 
/******************************************************************************\
* Relational operations.
\******************************************************************************/
 
#define JAS_FIX_CMP(fix_t, fracbits, x, y) \
        ((x) > (y) ? 1 : (((x) == (y)) ? 0 : (-1)))
 
#define JAS_FIX_LT(fix_t, fracbits, x, y) \
        ((x) < (y))
 
#define JAS_FIX_LTE(fix_t, fracbits, x, y) \
        ((x) <= (y))
 
#define JAS_FIX_GT(fix_t, fracbits, x, y) \
        ((x) > (y))
 
#define JAS_FIX_GTE(fix_t, fracbits, x, y) \
        ((x) >= (y))
 
/******************************************************************************\
* Rounding functions.
\******************************************************************************/
 
#define JAS_FIX_ROUND(fix_t, fracbits, x) \
        (((x) < 0) ? JAS_FIX_FLOOR(fix_t, fracbits, JAS_FIX_ADD(fix_t, fracbits, \
          (x), JAS_FIX_HALF(fix_t, fracbits))) : \
          JAS_FIX_NEG(fix_t, fracbits, JAS_FIX_FLOOR(fix_t, fracbits, \
          JAS_FIX_ADD(fix_t, fracbits, (-(x)), JAS_FIX_HALF(fix_t, fracbits)))))
 
#define JAS_FIX_FLOOR(fix_t, fracbits, x) \
        ((x) & (~(JAS_FIX_ONE(fix_t, fracbits) - 1)))
 
/******************************************************************************\
* The below macros are for internal library use only.  Do not invoke them
* directly in application code.
\******************************************************************************/
 
/* Handle overflow. */
#define JAS_FIX_OFLOW() \
        jas_logerrorf("overflow error: file %s, line %d\n", __FILE__, __LINE__)
 
/* Handle underflow. */
#define JAS_FIX_UFLOW() \
        jas_logerrorf("underflow error: file %s, line %d\n", __FILE__, __LINE__)
 
/******************************************************************************\
*
\******************************************************************************/
 
JAS_ATTRIBUTE_DISABLE_UBSAN
static inline jas_fix_t jas_fix_asl(jas_fix_t x, unsigned n)
{
        return JAS_FIX_ASL(jas_fix_t, 0, x, n);
}
 
JAS_ATTRIBUTE_DISABLE_UBSAN
static inline jas_fix_t jas_fix_asr(jas_fix_t x, unsigned n)
{
        return JAS_FIX_ASR(jas_fix_t, 0, x, n);
}
 
#ifdef __cplusplus
}
#endif
 
#endif