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/* hash.c -- hash table routines
Copyright (C) 1993, 1994, 1998, 2001 Free Software Foundation, Inc.
Written by Steve Chamberlain <sac@cygnus.com>
This file was lifted from BFD, the Binary File Descriptor library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "config.h"
#include "system.h"
#include "hash.h"
#include "obstack.h"
#include "toplev.h"
/* Obstack allocation and deallocation routines. */
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free
/* The default number of entries to use when creating a hash table. */
#define DEFAULT_SIZE 1009
/* Create a new hash table, given a number of entries. */
void
hash_table_init_n (table, newfunc, hash, comp, size)
struct hash_table *table;
struct hash_entry *(*newfunc) PARAMS ((struct hash_entry *,
struct hash_table *,
hash_table_key));
unsigned long (*hash) PARAMS ((hash_table_key));
bool (*comp) PARAMS ((hash_table_key, hash_table_key));
unsigned int size;
{
unsigned int alloc;
alloc = size * sizeof (struct hash_entry *);
obstack_begin (&table->memory, alloc);
table->table = ((struct hash_entry **)
obstack_alloc (&table->memory, alloc));
memset ((PTR) table->table, 0, alloc);
table->size = size;
table->newfunc = newfunc;
table->hash = hash;
table->comp = comp;
}
/* Create a new hash table with the default number of entries. */
void
hash_table_init (table, newfunc, hash, comp)
struct hash_table *table;
struct hash_entry *(*newfunc) PARAMS ((struct hash_entry *,
struct hash_table *,
hash_table_key));
unsigned long (*hash) PARAMS ((hash_table_key));
bool (*comp) PARAMS ((hash_table_key, hash_table_key));
{
hash_table_init_n (table, newfunc, hash, comp, DEFAULT_SIZE);
}
/* Free a hash table. */
void
hash_table_free (table)
struct hash_table *table;
{
obstack_free (&table->memory, (PTR) NULL);
}
/* Look up KEY in TABLE. If CREATE is non-NULL a new entry is
created if one does not previously exist. */
struct hash_entry *
hash_lookup (table, key, create, copy)
struct hash_table *table;
hash_table_key key;
int create;
hash_table_key (*copy) PARAMS ((struct obstack* memory,
hash_table_key key));
{
unsigned long hash;
struct hash_entry *hashp;
unsigned int index;
hash = (*table->hash)(key);
index = hash % table->size;
for (hashp = table->table[index]; hashp != 0; hashp = hashp->next)
if (hashp->hash == hash
&& (*table->comp)(hashp->key, key))
return hashp;
if (! create)
return 0;
hashp = (*table->newfunc) ((struct hash_entry *) NULL, table, key);
if (hashp == 0)
return 0;
if (copy)
key = (*copy) (&table->memory, key);
hashp->key = key;
hashp->hash = hash;
hashp->next = table->table[index];
table->table[index] = hashp;
return hashp;
}
/* Base method for creating a new hash table entry. */
struct hash_entry *
hash_newfunc (entry, table, p)
struct hash_entry *entry;
struct hash_table *table;
hash_table_key p ATTRIBUTE_UNUSED;
{
if (entry == 0)
entry = ((struct hash_entry *)
hash_allocate (table, sizeof (struct hash_entry)));
return entry;
}
/* Allocate space in a hash table. */
PTR
hash_allocate (table, size)
struct hash_table *table;
unsigned int size;
{
return obstack_alloc (&table->memory, size);
}
/* Traverse a hash table. */
void
hash_traverse (table, func, info)
struct hash_table *table;
bool (*func) PARAMS ((struct hash_entry *, hash_table_key));
PTR info;
{
unsigned int i;
struct hash_entry *p;
for (i = 0; i < table->size; i++)
for (p = table->table[i]; p != 0; p = p->next)
if (! (*func) (p, info))
return;
}
/* Hash a string. Return a hash-code for the string. */
unsigned long
string_hash (k)
hash_table_key k;
{
const unsigned char *s;
unsigned long hash;
unsigned char c;
unsigned int len;
s = (const unsigned char *) k;
hash = 0;
len = 0;
while ((c = *s++) != '\0')
{
hash += c + (c << 17);
hash ^= hash >> 2;
++len;
}
hash += len + (len << 17);
hash ^= hash >> 2;
return hash;
}
/* Compare two strings. Return non-zero iff the two strings are
the same. */
bool
string_compare (k1, k2)
hash_table_key k1;
hash_table_key k2;
{
return (strcmp ((char*) k1, (char*) k2) == 0);
}
/* Copy K to OBSTACK. */
hash_table_key
string_copy (memory, k)
struct obstack *memory;
hash_table_key k;
{
char *new;
char *string = (char *) k;
new = (char *) obstack_alloc (memory, strlen (string) + 1);
strcpy (new, string);
return new;
}
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