morelimitsimp.h

/**
 * copyright 2002-2004 Bryce "Zooko" Wilcox-O'Hearn
 * mailto:zooko@zooko.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software to deal in this software without restriction (including the
 * rights to use, modify, distribute, sublicense, and/or sell copies) provided
 * that the above copyright notice and this permission notice is included in
 * all copies or substantial portions of this software. THIS SOFTWARE IS
 * PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED.
 */

#ifndef __INCL_morelimitsimp_h
#define __INCL_morelimitsimp_h

#define Z_MAX_UNSIGNED(typ) ((typ)(~((typ)0)))
#define Z_MIN_UNSIGNED(typ) ((typ)0)

/* The following Z_MAX_SIGNED and Z_MIN_SIGNED macros will work on any C 
   implementation where the maximum value of a signed type (called typ) is 
   equal to 2^(sizeof(typ)*CHAR_BIT) - 1, and the minimum value of a signed 
   type is equal to the -1*(maximum value+1).  I guess that this includes every
   extant C implementation. */
#define Z_SIGNED_HIGH_BIT(typ) ((typ)(((typ)1) << ((sizeof(typ)*CHAR_BIT)-2)))
#define Z_SIGNED_LOW_BITS(typ) ((typ)(Z_SIGNED_HIGH_BIT(typ)-1))
#define Z_MAX_SIGNED(typ) ((typ)(Z_SIGNED_HIGH_BIT(typ) + Z_SIGNED_LOW_BITS(typ)))
#define Z_MIN_SIGNED(typ) ((typ)((-Z_MAX_SIGNED(typ))-1))

#define Z_MAX(typ) ((Z_MAX_SIGNED(typ) > Z_MAX_UNSIGNED(typ))?Z_MAX_SIGNED(typ):Z_MAX_UNSIGNED(typ))
#define Z_MAX2cast(typ) ((typ)((Z_MAX_SIGNED(typ) > Z_MAX_UNSIGNED(typ))?Z_MAX_SIGNED(typ):Z_MAX_UNSIGNED(typ)))
#define Z_MIN(typ) ((Z_MIN_SIGNED(typ) < Z_MIN_UNSIGNED(typ))?Z_MIN_SIGNED(typ):Z_MIN_UNSIGNED(typ))

#define Z_UNSIGNED_HIGH_BIT_BITS(b) (1ULL << ((b)-1))
#define Z_UNSIGNED_LOW_BITS_BITS(b) (Z_UNSIGNED_HIGH_BIT_BITS(b)-1)
#define Z_MAX_UNSIGNED_BITS(b) (Z_UNSIGNED_HIGH_BIT_BITS(b) | Z_UNSIGNED_LOW_BITS_BITS(b))

#endif /* #ifndef __INCL_morelimitsimp_h */