tools/ucl/src/ucl_ptr.h

   1 /* ucl_ptr.h -- low-level pointer constructs
   2
   3    This file is part of the UCL data compression library.
   4
   5    Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
   6    All Rights Reserved.
   7
   8    The UCL library is free software; you can redistribute it and/or
   9    modify it under the terms of the GNU General Public License as
  10    published by the Free Software Foundation; either version 2 of
  11    the License, or (at your option) any later version.
  12
  13    The UCL library is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with the UCL library; see the file COPYING.
  20    If not, write to the Free Software Foundation, Inc.,
  21    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  22
  23    Markus F.X.J. Oberhumer
  24    <markus@oberhumer.com>
  25  */
  26
  27
  28 /* WARNING: this file should *not* be used by applications. It is
  29    part of the implementation of the library and is subject
  30    to change.
  31  */
  32
  33
  34 #ifndef __UCL_PTR_H
  35 #define __UCL_PTR_H
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41
  42 /* This is the lowest part of the UCL library.
  43  * It deals with pointer representations at bit level.
  44  */
  45
  46
  47 /***********************************************************************
  48 // Includes
  49 ************************************************************************/
  50
  51 #if defined(__UCL_DOS16) || defined(__UCL_WIN16)
  52 #  include <dos.h>
  53 #  if 1 && defined(__WATCOMC__)
  54 #    include <i86.h>
  55      __UCL_EXTERN_C unsigned char _HShift;
  56 #    define __UCL_HShift    _HShift
  57 #  elif 1 && defined(_MSC_VER)
  58      __UCL_EXTERN_C unsigned short __near _AHSHIFT;
  59 #    define __UCL_HShift    ((unsigned) &_AHSHIFT)
  60 #  elif defined(__UCL_WIN16)
  61 #    define __UCL_HShift    3
  62 #  else
  63 #    define __UCL_HShift    12
  64 #  endif
  65 #  if !defined(_FP_SEG) && defined(FP_SEG)
  66 #    define _FP_SEG         FP_SEG
  67 #  endif
  68 #  if !defined(_FP_OFF) && defined(FP_OFF)
  69 #    define _FP_OFF         FP_OFF
  70 #  endif
  71 #endif
  72
  73
  74 /***********************************************************************
  75 // Integral types
  76 ************************************************************************/
  77
  78 /* ptrdiff_t */
  79 #if !defined(ucl_ptrdiff_t)
  80   #if (UINT_MAX >= UCL_0xffffffffL)
  81      typedef ptrdiff_t          ucl_ptrdiff_t;
  82   #else
  83      typedef long               ucl_ptrdiff_t;
  84   #endif
  85 #endif
  86
  87
  88 /* Unsigned type that has *exactly* the same number of bits as a ucl_voidp */
  89 #if !defined(__UCL_HAVE_PTR_T)
  90 #  if defined(ucl_ptr_t)
  91 #    define __UCL_HAVE_PTR_T
  92 #  endif
  93 #endif
  94 #if !defined(__UCL_HAVE_PTR_T)
  95 #  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED_LONG)
  96 #    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED_LONG)
  97        typedef unsigned long    ucl_ptr_t;
  98        typedef long             ucl_sptr_t;
  99 #      define __UCL_HAVE_PTR_T
 100 #    endif
 101 #  endif
 102 #endif
 103 #if !defined(__UCL_HAVE_PTR_T)
 104 #  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED)
 105 #    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED)
 106        typedef unsigned int     ucl_ptr_t;
 107        typedef int              ucl_sptr_t;
 108 #      define __UCL_HAVE_PTR_T
 109 #    endif
 110 #  endif
 111 #endif
 112 #if !defined(__UCL_HAVE_PTR_T)
 113 #  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED_SHORT)
 114 #    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED_SHORT)
 115        typedef unsigned short   ucl_ptr_t;
 116        typedef short            ucl_sptr_t;
 117 #      define __UCL_HAVE_PTR_T
 118 #    endif
 119 #  endif
 120 #endif
 121 #if !defined(__UCL_HAVE_PTR_T)
 122 #  if defined(UCL_HAVE_CONFIG_H) || defined(SIZEOF_CHAR_P)
 123 #    error "no suitable type for ucl_ptr_t"
 124 #  else
 125      typedef unsigned long      ucl_ptr_t;
 126      typedef long               ucl_sptr_t;
 127 #    define __UCL_HAVE_PTR_T
 128 #  endif
 129 #endif
 130
 131
 132 /***********************************************************************
 133 //
 134 ************************************************************************/
 135
 136 /* Always use the safe (=integral) version for pointer-comparisions.
 137  * The compiler should optimize away the additional casts anyway.
 138  *
 139  * Note that this only works if the representation and ordering
 140  * of the pointer and the integral is the same (at bit level).
 141  *
 142  * Most 16-bit compilers have their own view about pointers -
 143  * fortunately they don't care about comparing pointers
 144  * that are pointing to Nirvana.
 145  */
 146
 147 #if defined(__UCL_DOS16) || defined(__UCL_WIN16)
 148 #define PTR(a)              ((ucl_bytep) (a))
 149 /* only need the low bits of the pointer -> offset is ok */
 150 #define PTR_ALIGNED_4(a)    ((_FP_OFF(a) & 3) == 0)
 151 #define PTR_ALIGNED2_4(a,b) (((_FP_OFF(a) | _FP_OFF(b)) & 3) == 0)
 152 #else
 153 #define PTR(a)              ((ucl_ptr_t) (a))
 154 #define PTR_LINEAR(a)       PTR(a)
 155 #define PTR_ALIGNED_4(a)    ((PTR_LINEAR(a) & 3) == 0)
 156 #define PTR_ALIGNED_8(a)    ((PTR_LINEAR(a) & 7) == 0)
 157 #define PTR_ALIGNED2_4(a,b) (((PTR_LINEAR(a) | PTR_LINEAR(b)) & 3) == 0)
 158 #define PTR_ALIGNED2_8(a,b) (((PTR_LINEAR(a) | PTR_LINEAR(b)) & 7) == 0)
 159 #endif
 160
 161 #define PTR_LT(a,b)         (PTR(a) < PTR(b))
 162 #define PTR_GE(a,b)         (PTR(a) >= PTR(b))
 163 #define PTR_DIFF(a,b)       ((ucl_ptrdiff_t) (PTR(a) - PTR(b)))
 164
 165
 166 UCL_EXTERN(ucl_ptr_t)
 167 __ucl_ptr_linear(const ucl_voidp ptr);
 168
 169
 170 typedef union
 171 {
 172     char            a_char;
 173     unsigned char   a_uchar;
 174     short           a_short;
 175     unsigned short  a_ushort;
 176     int             a_int;
 177     unsigned int    a_uint;
 178     long            a_long;
 179     unsigned long   a_ulong;
 180     ucl_int         a_ucl_int;
 181     ucl_uint        a_ucl_uint;
 182     ucl_int32       a_ucl_int32;
 183     ucl_uint32      a_ucl_uint32;
 184     ptrdiff_t       a_ptrdiff_t;
 185     ucl_ptrdiff_t   a_ucl_ptrdiff_t;
 186     ucl_ptr_t       a_ucl_ptr_t;
 187     ucl_voidp       a_ucl_voidp;
 188     void *          a_void_p;
 189     ucl_bytep       a_ucl_bytep;
 190     ucl_bytepp      a_ucl_bytepp;
 191     ucl_uintp       a_ucl_uintp;
 192     ucl_uint *      a_ucl_uint_p;
 193     ucl_uint32p     a_ucl_uint32p;
 194     ucl_uint32 *    a_ucl_uint32_p;
 195     unsigned char * a_uchar_p;
 196     char *          a_char_p;
 197 }
 198 ucl_align_t;
 199
 200
 201
 202 #ifdef __cplusplus
 203 } /* extern "C" */
 204 #endif
 205
 206 #endif /* already included */
 207
 208 /*
 209 vi:ts=4:et
 210 */
 211