/* ucl_ptr.h -- low-level pointer constructs
 
 
 
   This file is part of the UCL data compression library.
 
 
 
   Copyright (C) 1996-2004 Markus Franz Xaver Johannes Oberhumer
 
   All Rights Reserved.
 
 
 
   The UCL library is free software; you can redistribute it and/or
 
   modify it under the terms of the GNU General Public License as
 
   published by the Free Software Foundation; either version 2 of
 
   the License, or (at your option) any later version.
 
 
 
   The UCL library is distributed in the hope that it will be useful,
 
   but WITHOUT ANY WARRANTY; without even the implied warranty of
 
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
   GNU General Public License for more details.
 
 
 
   You should have received a copy of the GNU General Public License
 
   along with the UCL library; see the file COPYING.
 
   If not, write to the Free Software Foundation, Inc.,
 
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 
 
   Markus F.X.J. Oberhumer
 
   <markus@oberhumer.com>
 
   http://www.oberhumer.com/opensource/ucl/
 
 */
 
 
 
 
 
/* WARNING: this file should *not* be used by applications. It is
 
   part of the implementation of the library and is subject
 
   to change.
 
 */
 
 
 
 
 
#ifndef __UCL_PTR_H
 
#define __UCL_PTR_H
 
 
 
#ifdef __cplusplus
 
extern "C" {
 
#endif
 
 
 
 
 
/***********************************************************************
 
// Integral types
 
************************************************************************/
 
 
 
#if !defined(ucl_uintptr_t)
 
#  define ucl_uintptr_t     acc_uintptr_t
 
#endif
 
 
 
 
 
/***********************************************************************
 
//
 
************************************************************************/
 
 
 
/* Always use the safe (=integral) version for pointer-comparisions.
 
 * The compiler should optimize away the additional casts anyway.
 
 *
 
 * Note that this only works if the representation and ordering
 
 * of the pointer and the integral is the same (at bit level).
 
 *
 
 * Most 16-bit compilers have their own view about pointers -
 
 * fortunately they don't care about comparing pointers
 
 * that are pointing to Nirvana.
 
 */
 
 
 
#if (ACC_OS_DOS16 || ACC_OS_OS216 || ACC_OS_WIN16)
 
#define PTR(a)              ((ucl_bytep) (a))
 
/* only need the low bits of the pointer -> offset is ok */
 
#define PTR_ALIGNED_4(a)    ((ACC_FP_OFF(a) & 3) == 0)
 
#define PTR_ALIGNED2_4(a,b) (((ACC_FP_OFF(a) | ACC_FP_OFF(b)) & 3) == 0)
 
#else
 
#define PTR(a)              ((ucl_uintptr_t) (a))
 
#define PTR_LINEAR(a)       PTR(a)
 
#define PTR_ALIGNED_4(a)    ((PTR_LINEAR(a) & 3) == 0)
 
#define PTR_ALIGNED_8(a)    ((PTR_LINEAR(a) & 7) == 0)
 
#define PTR_ALIGNED2_4(a,b) (((PTR_LINEAR(a) | PTR_LINEAR(b)) & 3) == 0)
 
#define PTR_ALIGNED2_8(a,b) (((PTR_LINEAR(a) | PTR_LINEAR(b)) & 7) == 0)
 
#endif
 
 
 
#define PTR_LT(a,b)         (PTR(a) < PTR(b))
 
#define PTR_GE(a,b)         (PTR(a) >= PTR(b))
 
 
 
 
 
UCL_EXTERN(ucl_uintptr_t)
 
__ucl_ptr_linear(const ucl_voidp ptr);
 
 
 
 
 
typedef union
 
{
 
    char            a_char;
 
    unsigned char   a_uchar;
 
    short           a_short;
 
    unsigned short  a_ushort;
 
    int             a_int;
 
    unsigned int    a_uint;
 
    long            a_long;
 
    unsigned long   a_ulong;
 
    ucl_int         a_ucl_int;
 
    ucl_uint        a_ucl_uint;
 
    ucl_int32       a_ucl_int32;
 
    ucl_uint32      a_ucl_uint32;
 
    ptrdiff_t       a_ptrdiff_t;
 
    ucl_uintptr_t   a_ucl_uintptr_t;
 
    ucl_voidp       a_ucl_voidp;
 
    void *          a_void_p;
 
    ucl_bytep       a_ucl_bytep;
 
    ucl_bytepp      a_ucl_bytepp;
 
    ucl_uintp       a_ucl_uintp;
 
    ucl_uint *      a_ucl_uint_p;
 
    ucl_uint32p     a_ucl_uint32p;
 
    ucl_uint32 *    a_ucl_uint32_p;
 
    unsigned char * a_uchar_p;
 
    char *          a_char_p;
 
}
 
ucl_align_t;
 
 
 
 
 
 
 
#ifdef __cplusplus
 
} /* extern "C" */
 
#endif
 
 
 
#endif /* already included */
 
 
 
/*
 
vi:ts=4:et
 
*/