mirror of
https://github.com/Mercury-Language/mercury.git
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aab560b8c7
Estimated hours taken: 0.5 runtime/mercury_table.c: runtime/mercury_memory.c: Fix a couple of bugs where the macro USE_DLLs was referenced without having previously done "#include mercury_conf.h". runtime/conf.h.in: Some minor improvements to the comments.
144 lines
2.5 KiB
C
144 lines
2.5 KiB
C
/*
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** Copyright (C) 1993-1997 The 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 "mercury_imp.h"
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#include <stdio.h>
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#include "mercury_std.h"
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#include "mercury_dlist.h"
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#include "mercury_table.h"
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/*
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** Initialize a table.
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*/
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void
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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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/*
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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 *
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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 "
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"lookup_table: %d, table size %d\n",
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h, table->ta_size);
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}
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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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}
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}
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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
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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 "
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"lookup_table: %d, table size %d\n",
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h, table->ta_size);
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}
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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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}
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}
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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 *
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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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}
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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
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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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}
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if (h < 0) {
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h = -h;
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}
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return h;
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}
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