gcc/f/bit.c

   1 /* bit.c -- Implementation File (module.c template V1.0)
   2    Copyright (C) 1995 Free Software Foundation, Inc.
   3    Contributed by James Craig Burley.
   4
   5 This file is part of GNU Fortran.
   6
   7 GNU Fortran is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Fortran is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Fortran; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.
  21
  22    Related Modules:
  23       None
  24
  25    Description:
  26       Tracks arrays of booleans in useful ways.
  27
  28    Modifications:
  29 */
  30
  31 /* Include files. */
  32
  33 #include "proj.h"
  34 #include "bit.h"
  35 #include "malloc.h"
  36
  37 /* Externals defined here. */
  38
  39
  40 /* Simple definitions and enumerations. */
  41
  42
  43 /* Internal typedefs. */
  44
  45
  46 /* Private include files. */
  47
  48
  49 /* Internal structure definitions. */
  50
  51
  52 /* Static objects accessed by functions in this module. */
  53
  54
  55 /* Static functions (internal). */
  56
  57
  58 /* Internal macros. */
  59 \f
  60
  61 /* ffebit_count -- Count # of bits set a particular way
  62
  63    ffebit b;  // the ffebit object
  64    ffebitCount offset;  // 0..size-1
  65    bool value;  // FALSE (0), TRUE (1)
  66    ffebitCount range;  // # bits to test
  67    ffebitCount number;  // # bits equal to value
  68    ffebit_count(b,offset,value,range,&number);
  69
  70    Sets <number> to # bits at <offset> through <offset + range - 1> set to
  71    <value>.  If <range> is 0, <number> is set to 0.  */
  72
  73 void
  74 ffebit_count (ffebit b, ffebitCount offset, bool value, ffebitCount range,
  75               ffebitCount *number)
  76 {
  77   ffebitCount element;
  78   ffebitCount bitno;
  79
  80   assert (offset + range <= b->size);
  81
  82   for (*number = 0; range != 0; --range, ++offset)
  83     {
  84       element = offset / CHAR_BIT;
  85       bitno = offset % CHAR_BIT;
  86       if (value
  87           == ((b->bits[element] & ((unsigned char) 1 << bitno)) == 0 ? FALSE : TRUE))
  88         ++ * number;
  89     }
  90 }
  91
  92 /* ffebit_new -- Create a new ffebit object
  93
  94    ffebit b;
  95    ffebit_kill(b);
  96
  97    Destroys an ffebit object obtained via ffebit_new.  */
  98
  99 void
 100 ffebit_kill (ffebit b)
 101 {
 102   malloc_kill_ks (b->pool, b,
 103                   offsetof (struct _ffebit_, bits)
 104                   + (b->size + CHAR_BIT - 1) / CHAR_BIT);
 105 }
 106
 107 /* ffebit_new -- Create a new ffebit object
 108
 109    ffebit b;
 110    mallocPool pool;
 111    ffebitCount size;
 112    b = ffebit_new(pool,size);
 113
 114    Allocates an ffebit object that holds the values of <size> bits in pool
 115    <pool>.  */
 116
 117 ffebit
 118 ffebit_new (mallocPool pool, ffebitCount size)
 119 {
 120   ffebit b;
 121
 122   b = malloc_new_zks (pool, "ffebit",
 123                       offsetof (struct _ffebit_, bits)
 124                       + (size + CHAR_BIT - 1) / CHAR_BIT,
 125                       0);
 126   b->pool = pool;
 127   b->size = size;
 128
 129   return b;
 130 }
 131
 132 /* ffebit_set -- Set value of # of bits
 133
 134    ffebit b;  // the ffebit object
 135    ffebitCount offset;  // 0..size-1
 136    bool value;  // FALSE (0), TRUE (1)
 137    ffebitCount length;  // # bits to set starting at offset (usually 1)
 138    ffebit_set(b,offset,value,length);
 139
 140    Sets bit #s <offset> through <offset + length - 1> to <value>.  */
 141
 142 void
 143 ffebit_set (ffebit b, ffebitCount offset, bool value, ffebitCount length)
 144 {
 145   ffebitCount i;
 146   ffebitCount element;
 147   ffebitCount bitno;
 148
 149   assert (offset + length <= b->size);
 150
 151   for (i = 0; i < length; ++i, ++offset)
 152     {
 153       element = offset / CHAR_BIT;
 154       bitno = offset % CHAR_BIT;
 155       b->bits[element] = (((unsigned char) (value ? 1 : 0)) << bitno)
 156         | (b->bits[element] & ~((unsigned char) 1 << bitno));
 157     }
 158 }
 159
 160 /* ffebit_test -- Test value of # of bits
 161
 162    ffebit b;  // the ffebit object
 163    ffebitCount offset;  // 0..size-1
 164    bool value;  // FALSE (0), TRUE (1)
 165    ffebitCount length;  // # bits with same value
 166    ffebit_test(b,offset,&value,&length);
 167
 168    Returns value of bits at <offset> through <offset + length - 1> in
 169    <value>.  If <offset> is already at the end of the bit array (if
 170    offset == ffebit_size(b)), <length> is set to 0 and <value> is
 171    undefined.  */
 172
 173 void
 174 ffebit_test (ffebit b, ffebitCount offset, bool *value, ffebitCount *length)
 175 {
 176   ffebitCount i;
 177   ffebitCount element;
 178   ffebitCount bitno;
 179
 180   if (offset >= b->size)
 181     {
 182       assert (offset == b->size);
 183       *length = 0;
 184       return;
 185     }
 186
 187   element = offset / CHAR_BIT;
 188   bitno = offset % CHAR_BIT;
 189   *value = (b->bits[element] & ((unsigned char) 1 << bitno)) == 0 ? FALSE : TRUE;
 190   *length = 1;
 191
 192   for (i = b->size - offset - 1, ++offset; i != 0; --i, ++offset, ++*length)
 193     {
 194       element = offset / CHAR_BIT;
 195       bitno = offset % CHAR_BIT;
 196       if (*value
 197           != ((b->bits[element] & ((unsigned char) 1 << bitno)) == 0 ? FALSE : TRUE))
 198         break;
 199     }
 200 }