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0a82600fac
wrapper.mod: Only return the first solution to main/2, rather than all solutions. table.c: Remove unnecessary assert(), since it caused a warning, and since the condition it checks for is already checked for in newmem(). CFLAGSFILE, PORTABILITY: Minor changes.
124 lines
2.4 KiB
C
124 lines
2.4 KiB
C
/*
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** Copyright (C) 1995 University of Melbourne.
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** This file may only be copied under the terms of the GNU Library General
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** Public License - see the file COPYING.LIB in the Mercury distribution.
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*/
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/*
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** Table handling module.
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**
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** This file supplies data manipulation routines to other modules;
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** it does not store any data itself. Its routines are generic,
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** applicable to the storage of any kind of data structure with
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** a primary key and a hash function on it.
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*/
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#define HASHDEBUG
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#include <stdio.h>
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#include <assert.h>
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#include "std.h"
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#include "dlist.h"
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#include "table.h"
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/*
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** Initialize a table.
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*/
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void tab_init_table(Table *table)
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{
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reg int i;
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table->ta_store = make_many(List *, table->ta_size);
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for (i = 0; i < table->ta_size; i++)
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table->ta_store[i] = NULL;
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}
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/*
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** Look up and return the entry corresponding to the key
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** in a table.
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*/
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void *tab_lookup_table(const Table *table, const void *key)
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{
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reg List *ptr;
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reg int h;
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h = tablehash(table)(key);
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#ifdef HASHDEBUG
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if (! (0 <= h && h < table->ta_size))
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fprintf(stderr, "internal error: bad hash index in lookup_table: %d, table size %d\n", h, table->ta_size);
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#endif
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for_list (ptr, table->ta_store[h])
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if (tableequal(table)(key, tablekey(table)(ldata(ptr))))
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return ldata(ptr);
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return NULL;
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}
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/*
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** Insert a new entry into the table.
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** Return whether it was there before.
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*/
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bool tab_insert_table(const Table *table, void *entry)
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{
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reg List *ptr;
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reg const void *key;
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reg int h;
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key = tablekey(table)(entry);
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h = tablehash(table)(key);
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#ifdef HASHDEBUG
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if (! (0 <= h && h < table->ta_size))
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fprintf(stderr, "internal error: bad hash index in lookup_table: %d, table size %d\n", h, table->ta_size);
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#endif
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for_list (ptr, table->ta_store[h])
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if (tableequal(table)(key, tablekey(table)(ldata(ptr))))
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return TRUE;
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table->ta_store[h] = addhead(table->ta_store[h], entry);
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return FALSE;
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}
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/*
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** Return all table entries in a list.
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*/
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List *tab_get_all_entries(const Table *table)
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{
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reg List *list;
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reg int i;
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list = makelist0();
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for (i = 0; i < table->ta_size; i++)
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addndlist(list, table->ta_store[i]);
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return list;
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}
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/*
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** Convert a string to a positive int. The return value
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** mod the table size is a good hash value.
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*/
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int tab_str_to_int(const char *cs)
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{
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reg int h;
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reg const char *s;
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s = cs;
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for (h = 0; *s != '\0'; s++)
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h = (h << 1) + *s;
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if (h < 0)
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h = -h;
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return h;
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}
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