mdw@git.distorted.org.uk Git - become/blob - src/set.c

   1 /* -*-c-*-
   2  *
   3  * $Id: set.c,v 1.1 1997/07/21 13:47:44 mdw Exp $
   4  *
   5  * Management of sets (for the use of the class expression handler)
   6  *
   7  * (c) 1997 EBI
   8  */
   9
  10 /*----- Licencing notice --------------------------------------------------*
  11  *
  12  * This file is part of `become'
  13  *
  14  * `Become' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `Become' is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `become'; if not, write to the Free Software
  26  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: set.c,v $
  32  * Revision 1.1  1997/07/21 13:47:44  mdw
  33  * Initial revision
  34  *
  35  */
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 /* --- ANSI headers --- */
  40
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44
  45 /* --- Local headers --- */
  46
  47 #include "set.h"
  48 #include "sym.h"
  49 #include "utils.h"
  50
  51 /*----- Main code ---------------------------------------------------------*/
  52
  53 /* --- @set_subtract@ --- *
  54  *
  55  * Arguments:   @sym_table *a@ = pointer to table @A@
  56  *              @sym_table *b@ = pointer to table @B@
  57  *
  58  * Returns:     A symbol table containing all the elements in @A@ which don't
  59  *              appear in @B@.
  60  *
  61  * Use:         Subtracts a symbol table from another symbol table.  Assumes
  62  *              that there's no data following the actual @sym_base@ block
  63  *              for each item in the table.
  64  */
  65
  66 sym_table *set_subtract(sym_table *a, sym_table *b)
  67 {
  68   sym_table *c = xmalloc(sizeof(*c));
  69   sym_iter i;
  70   sym_base *s;
  71   unsigned f;
  72
  73   sym_createTable(c);
  74   for (sym_createIter(&i, a); (s = sym_next(&i)) != 0; ) {
  75     if (!sym_find(b, s->name, s->len, 0, &f))
  76       sym_find(c, s->name, s->len, sizeof(sym_base), 0);
  77   }
  78
  79   return (c);
  80 }
  81
  82 /* --- @set_intersect@ --- *
  83  *
  84  * Arguments:   @sym_table *a@ = pointer to table @A@
  85  *              @sym_table *b@ = pointer to table @B@
  86  *
  87  * Returns:     A symbol table containing all the elements in @A@ which also
  88  *              appear in @B@.
  89  *
  90  * Use:         Constructs the intersection of two symbol tables.  Assumes
  91  *              that there's no data following the actual @sym_base@ block
  92  *              for each item in the table.
  93  */
  94
  95 sym_table *set_intersect(sym_table *a, sym_table *b)
  96 {
  97   sym_table *c = xmalloc(sizeof(*c));
  98   sym_iter i;
  99   sym_base *s;
 100   unsigned f;
 101
 102   sym_createTable(c);
 103   for (sym_createIter(&i, a); (s = sym_next(&i)) != 0; ) {
 104     if (sym_find(b, s->name, s->len, 0, &f))
 105       sym_find(c, s->name, s->len, sizeof(sym_base), 0);
 106   }
 107
 108   return (c);
 109 }
 110
 111 /* --- @set_union@ --- *
 112  *
 113  * Arguments:   @sym_table *a@ = pointer to table @A@
 114  *              @sym_table *b@ = pointer to table @B@
 115  *
 116  * Returns:     A symbol table containing all the elements in @A@ and those
 117  *              in @B@.
 118  *
 119  * Use:         Constructs the union of two symbol tables.  Assumes that
 120  *              there's no data following the actual @sym_base@ block for
 121  *              each item in the table.
 122  */
 123
 124 sym_table *set_union(sym_table *a, sym_table *b)
 125 {
 126   sym_table *c = xmalloc(sizeof(*c));
 127   sym_iter i;
 128   sym_base *s;
 129
 130   sym_createTable(c);
 131   for (sym_createIter(&i, a); (s = sym_next(&i)) != 0; )
 132     sym_find(c, s->name, s->len, sizeof(sym_base), 0);
 133
 134   for (sym_createIter(&i, b); (s = sym_next(&i)) != 0; )
 135     sym_find(c, s->name, s->len, sizeof(sym_base), 0);
 136
 137   return (c);
 138 }
 139
 140 /* --- @set_copy@ --- *
 141  *
 142  * Arguments:   @sym_table *a@ = pointer to table
 143  *
 144  * Returns:     A copy of the symbol table.
 145  *
 146  * Use:         Copies a symbol table.  Same assumptions again...
 147  */
 148
 149 sym_table *set_copy(sym_table *a)
 150 {
 151   sym_table *c = xmalloc(sizeof(*c));
 152   sym_iter i;
 153   sym_base *s;
 154
 155   for (sym_createIter(&i, a); (s = sym_next(&i)) != 0; )
 156     sym_find(c, s->name, s->len, sizeof(sym_base), 0);
 157
 158   return (c);
 159 }
 160
 161 /*----- That's all, folks -------------------------------------------------*/