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/* CYGNUS LOCAL: whole file jason */
/* hash.c -- hash table routines
Copyright (C) 1993, 94 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, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "config.h"
#include "hash.h"
#include "obstack.h"
extern void free PARAMS ((PTR));
/* Obstack allocation and deallocation routines. */
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free
extern char * xmalloc ();
/* The default number of entries to use when creating a hash table. */
#define DEFAULT_SIZE (1009)
#ifndef NULL
#define NULL 0
#endif
/* Create a new hash table, given a number of entries. */
boolean
hash_table_init_n (table, newfunc, size)
struct hash_table *table;
struct hash_entry *(*newfunc) PARAMS ((struct hash_entry *,
struct hash_table *,
const char *));
unsigned int size;
{
unsigned int alloc;
alloc = size * sizeof (struct hash_entry *);
if (!obstack_begin (&table->memory, alloc))
{
error ("no memory");
return false;
}
table->table = ((struct hash_entry **)
obstack_alloc (&table->memory, alloc));
if (!table->table)
{
error ("no memory");
return false;
}
memset ((PTR) table->table, 0, alloc);
table->size = size;
table->newfunc = newfunc;
return true;
}
/* Create a new hash table with the default number of entries. */
boolean
hash_table_init (table, newfunc)
struct hash_table *table;
struct hash_entry *(*newfunc) PARAMS ((struct hash_entry *,
struct hash_table *,
const char *));
{
return hash_table_init_n (table, newfunc, DEFAULT_SIZE);
}
/* Free a hash table. */
void
hash_table_free (table)
struct hash_table *table;
{
obstack_free (&table->memory, (PTR) NULL);
}
/* Look up a string in a hash table. */
struct hash_entry *
hash_lookup (table, string, create, copy)
struct hash_table *table;
const char *string;
boolean create;
boolean copy;
{
register const unsigned char *s;
register unsigned long hash;
register unsigned int c;
struct hash_entry *hashp;
unsigned int len;
unsigned int index;
hash = 0;
len = 0;
s = (const unsigned char *) string;
while ((c = *s++) != '\0')
{
hash += c + (c << 17);
hash ^= hash >> 2;
++len;
}
hash += len + (len << 17);
hash ^= hash >> 2;
index = hash % table->size;
for (hashp = table->table[index];
hashp != (struct hash_entry *) NULL;
hashp = hashp->next)
{
if (hashp->hash == hash
&& strcmp (hashp->string, string) == 0)
return hashp;
}
if (! create)
return (struct hash_entry *) NULL;
hashp = (*table->newfunc) ((struct hash_entry *) NULL, table, string);
if (hashp == (struct hash_entry *) NULL)
return (struct hash_entry *) NULL;
if (copy)
{
char *new;
new = (char *) obstack_alloc (&table->memory, len + 1);
if (!new)
{
error ("no memory");
return (struct hash_entry *) NULL;
}
strcpy (new, string);
string = new;
}
hashp->string = string;
hashp->hash = hash;
hashp->next = table->table[index];
table->table[index] = hashp;
return hashp;
}
/* Base method for creating a new hash table entry. */
/*ARGSUSED*/
struct hash_entry *
hash_newfunc (entry, table, string)
struct hash_entry *entry;
struct hash_table *table;
const char *string;
{
if (entry == (struct hash_entry *) NULL)
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;
{
PTR ret;
ret = obstack_alloc (&table->memory, size);
if (ret == NULL && size != 0)
error ("no memory");
return ret;
}
/* Traverse a hash table. */
void
hash_traverse (table, func, info)
struct hash_table *table;
boolean (*func) PARAMS ((struct hash_entry *, PTR));
PTR info;
{
unsigned int i;
for (i = 0; i < table->size; i++)
{
struct hash_entry *p;
for (p = table->table[i]; p != NULL; p = p->next)
{
if (! (*func) (p, info))
return;
}
}
}
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