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/* ucl_ptr.h -- low-level pointer constructs

   This file is part of the UCL data compression library.

   Copyright (C) 1996-2002 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>

 */

/* 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

/* This is the lowest part of the UCL library.

 * It deals with pointer representations at bit level.

 */

/***********************************************************************

// Includes

************************************************************************/

#if defined(__UCL_DOS16) || defined(__UCL_WIN16)

#  include <dos.h>

#  if 1 && defined(__WATCOMC__)

#    include <i86.h>

     __UCL_EXTERN_C unsigned char _HShift;

#    define __UCL_HShift    _HShift

#  elif 1 && defined(_MSC_VER)

     __UCL_EXTERN_C unsigned short __near _AHSHIFT;

#    define __UCL_HShift    ((unsigned) &_AHSHIFT)

#  elif defined(__UCL_WIN16)

#    define __UCL_HShift    3

#  else

#    define __UCL_HShift    12

#  endif

#  if !defined(_FP_SEG) && defined(FP_SEG)

#    define _FP_SEG         FP_SEG

#  endif

#  if !defined(_FP_OFF) && defined(FP_OFF)

#    define _FP_OFF         FP_OFF

#  endif

#endif

/***********************************************************************

// Integral types

************************************************************************/

/* ptrdiff_t */

#if !defined(ucl_ptrdiff_t)

  #if (UINT_MAX >= UCL_0xffffffffL)

     typedef ptrdiff_t          ucl_ptrdiff_t;

  #else

     typedef long               ucl_ptrdiff_t;

  #endif

#endif

/* Unsigned type that has *exactly* the same number of bits as a ucl_voidp */

#if !defined(__UCL_HAVE_PTR_T)

#  if defined(ucl_ptr_t)

#    define __UCL_HAVE_PTR_T

#  endif

#endif

#if !defined(__UCL_HAVE_PTR_T)

#  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED_LONG)

#    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED_LONG)

       typedef unsigned long    ucl_ptr_t;

       typedef long             ucl_sptr_t;

#      define __UCL_HAVE_PTR_T

#    endif

#  endif

#endif

#if !defined(__UCL_HAVE_PTR_T)

#  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED)

#    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED)

       typedef unsigned int     ucl_ptr_t;

       typedef int              ucl_sptr_t;

#      define __UCL_HAVE_PTR_T

#    endif

#  endif

#endif

#if !defined(__UCL_HAVE_PTR_T)

#  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED_SHORT)

#    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED_SHORT)

       typedef unsigned short   ucl_ptr_t;

       typedef short            ucl_sptr_t;

#      define __UCL_HAVE_PTR_T

#    endif

#  endif

#endif

#if !defined(__UCL_HAVE_PTR_T)

#  if defined(UCL_HAVE_CONFIG_H) || defined(SIZEOF_CHAR_P)

#    error "no suitable type for ucl_ptr_t"

#  else

     typedef unsigned long      ucl_ptr_t;

     typedef long               ucl_sptr_t;

#    define __UCL_HAVE_PTR_T

#  endif

#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 defined(__UCL_DOS16) || defined(__UCL_WIN16)

#define PTR(a)              ((ucl_bytep) (a))

/* only need the low bits of the pointer -> offset is ok */

#define PTR_ALIGNED_4(a)    ((_FP_OFF(a) & 3) == 0)

#define PTR_ALIGNED2_4(a,b) (((_FP_OFF(a) | _FP_OFF(b)) & 3) == 0)

#else

#define PTR(a)              ((ucl_ptr_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))

#define PTR_DIFF(a,b)       ((ucl_ptrdiff_t) (PTR(a) - PTR(b)))

UCL_EXTERN(ucl_ptr_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_ptrdiff_t   a_ucl_ptrdiff_t;

    ucl_ptr_t       a_ucl_ptr_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

*/