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246 lines
5.7 KiB
C
246 lines
5.7 KiB
C
/* hash.c -- hash table routines
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Copyright (C) 1993, 1994, 1998 Free Software Foundation, Inc.
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Written by Steve Chamberlain <sac@cygnus.com>
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This file was lifted from BFD, the Binary File Descriptor library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "config.h"
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#include "system.h"
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#include "hash.h"
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#include "obstack.h"
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#include "toplev.h"
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/* Obstack allocation and deallocation routines. */
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#define obstack_chunk_alloc xmalloc
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#define obstack_chunk_free free
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/* The default number of entries to use when creating a hash table. */
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#define DEFAULT_SIZE (1009)
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/* Create a new hash table, given a number of entries. */
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boolean
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hash_table_init_n (table, newfunc, hash, comp, size)
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struct hash_table *table;
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struct hash_entry *(*newfunc) PARAMS ((struct hash_entry *,
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struct hash_table *,
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hash_table_key));
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unsigned long (*hash) PARAMS ((hash_table_key));
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boolean (*comp) PARAMS ((hash_table_key, hash_table_key));
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unsigned int size;
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{
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unsigned int alloc;
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alloc = size * sizeof (struct hash_entry *);
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if (!obstack_begin (&table->memory, alloc))
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{
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error ("no memory");
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return false;
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}
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table->table = ((struct hash_entry **)
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obstack_alloc (&table->memory, alloc));
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if (!table->table)
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{
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error ("no memory");
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return false;
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}
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memset ((PTR) table->table, 0, alloc);
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table->size = size;
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table->newfunc = newfunc;
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table->hash = hash;
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table->comp = comp;
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return true;
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}
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/* Create a new hash table with the default number of entries. */
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boolean
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hash_table_init (table, newfunc, hash, comp)
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struct hash_table *table;
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struct hash_entry *(*newfunc) PARAMS ((struct hash_entry *,
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struct hash_table *,
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hash_table_key));
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unsigned long (*hash) PARAMS ((hash_table_key));
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boolean (*comp) PARAMS ((hash_table_key, hash_table_key));
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{
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return hash_table_init_n (table, newfunc, hash, comp, DEFAULT_SIZE);
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}
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/* Free a hash table. */
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void
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hash_table_free (table)
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struct hash_table *table;
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{
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obstack_free (&table->memory, (PTR) NULL);
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}
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/* Look up KEY in TABLE. If CREATE is non-NULL a new entry is
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created if one does not previously exist. */
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struct hash_entry *
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hash_lookup (table, key, create, copy)
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struct hash_table *table;
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hash_table_key key;
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boolean create;
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hash_table_key (*copy) PARAMS ((struct obstack* memory,
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hash_table_key key));
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{
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register unsigned long hash;
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struct hash_entry *hashp;
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unsigned int index;
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hash = (*table->hash)(key);
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index = hash % table->size;
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for (hashp = table->table[index];
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hashp != (struct hash_entry *) NULL;
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hashp = hashp->next)
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{
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if (hashp->hash == hash
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&& (*table->comp)(hashp->key, key))
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return hashp;
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}
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if (! create)
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return (struct hash_entry *) NULL;
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hashp = (*table->newfunc) ((struct hash_entry *) NULL, table, key);
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if (hashp == (struct hash_entry *) NULL)
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return (struct hash_entry *) NULL;
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if (copy)
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key = (*copy) (&table->memory, key);
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hashp->key = key;
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hashp->hash = hash;
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hashp->next = table->table[index];
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table->table[index] = hashp;
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return hashp;
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}
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/* Base method for creating a new hash table entry. */
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/*ARGSUSED*/
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struct hash_entry *
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hash_newfunc (entry, table, p)
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struct hash_entry *entry;
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struct hash_table *table;
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hash_table_key p;
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{
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if (entry == (struct hash_entry *) NULL)
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entry = ((struct hash_entry *)
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hash_allocate (table, sizeof (struct hash_entry)));
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return entry;
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}
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/* Allocate space in a hash table. */
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PTR
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hash_allocate (table, size)
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struct hash_table *table;
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unsigned int size;
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{
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PTR ret;
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ret = obstack_alloc (&table->memory, size);
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if (ret == NULL && size != 0)
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error ("no memory");
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return ret;
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}
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/* Traverse a hash table. */
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void
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hash_traverse (table, func, info)
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struct hash_table *table;
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boolean (*func) PARAMS ((struct hash_entry *, hash_table_key));
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PTR info;
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{
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unsigned int i;
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for (i = 0; i < table->size; i++)
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{
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struct hash_entry *p;
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for (p = table->table[i]; p != NULL; p = p->next)
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{
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if (! (*func) (p, info))
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return;
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}
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}
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}
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/* Hash a string. Return a hash-code for the string. */
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unsigned long
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string_hash (k)
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hash_table_key k;
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{
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const unsigned char *s;
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unsigned long hash;
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unsigned char c;
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unsigned int len;
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s = (const unsigned char *) k;
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hash = 0;
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len = 0;
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while ((c = *s++) != '\0')
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{
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hash += c + (c << 17);
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hash ^= hash >> 2;
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++len;
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}
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hash += len + (len << 17);
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hash ^= hash >> 2;
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return hash;
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}
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/* Compare two strings. Return non-zero iff the two strings are
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the same. */
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boolean
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string_compare (k1, k2)
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hash_table_key k1;
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hash_table_key k2;
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{
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return (strcmp ((char*) k1, (char*) k2) == 0);
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}
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/* Copy K to OBSTACK. */
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hash_table_key
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string_copy (memory, k)
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struct obstack* memory;
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hash_table_key k;
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{
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char *new;
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char *string = (char*) k;
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new = (char *) obstack_alloc (memory, strlen (string) + 1);
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if (!new)
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{
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error ("no memory");
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return NULL;
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}
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strcpy (new, string);
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return new;
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}
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