GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/stdlib/hcreate.c Lines: 0 46 0.0 %
Date: 2017-11-13 Branches: 0 30 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: hcreate.c,v 1.7 2016/05/29 20:47:49 guenther Exp $	*/
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/*	$NetBSD: hcreate.c,v 1.5 2004/04/23 02:48:12 simonb Exp $	*/
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/*
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 * Copyright (c) 2001 Christopher G. Demetriou
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *          This product includes software developed for the
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 *          NetBSD Project.  See http://www.NetBSD.org/ for
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 *          information about NetBSD.
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 * 4. The name of the author may not be used to endorse or promote products
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 *    derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 *
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 * <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
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 */
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/*
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 * hcreate() / hsearch() / hdestroy()
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 *
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 * SysV/XPG4 hash table functions.
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 *
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 * Implementation done based on NetBSD manual page and Solaris manual page,
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 * plus my own personal experience about how they're supposed to work.
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 *
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 * I tried to look at Knuth (as cited by the Solaris manual page), but
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 * nobody had a copy in the office, so...
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 */
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#include <assert.h>
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#include <errno.h>
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#include <stdint.h>
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#include <search.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/queue.h>
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#include <db.h>		/* for __default_hash */
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#ifndef _DIAGASSERT
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#define _DIAGASSERT(x)
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#endif
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/*
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 * DO NOT MAKE THIS STRUCTURE LARGER THAN 32 BYTES (4 ptrs on 64-bit
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 * ptr machine) without adjusting MAX_BUCKETS_LG2 below.
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 */
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struct internal_entry {
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	SLIST_ENTRY(internal_entry) link;
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	ENTRY ent;
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};
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SLIST_HEAD(internal_head, internal_entry);
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#define	MIN_BUCKETS_LG2	4
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#define	MIN_BUCKETS	(1 << MIN_BUCKETS_LG2)
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/*
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 * max * sizeof internal_entry must fit into size_t.
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 * assumes internal_entry is <= 32 (2^5) bytes.
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 */
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#define	MAX_BUCKETS_LG2	(sizeof (size_t) * 8 - 1 - 5)
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#define	MAX_BUCKETS	((size_t)1 << MAX_BUCKETS_LG2)
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static struct internal_head *htable;
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static size_t htablesize;
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int
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hcreate(size_t nel)
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{
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	size_t idx;
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	unsigned int p2;
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	/* Make sure this isn't called when a table already exists. */
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	_DIAGASSERT(htable == NULL);
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	if (htable != NULL) {
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		errno = EINVAL;
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		return 0;
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	}
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	/* If nel is too small, make it min sized. */
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	if (nel < MIN_BUCKETS)
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		nel = MIN_BUCKETS;
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	/* If it's too large, cap it. */
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	if (nel > MAX_BUCKETS)
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		nel = MAX_BUCKETS;
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	/* If it's is not a power of two in size, round up. */
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	if ((nel & (nel - 1)) != 0) {
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		for (p2 = 0; nel != 0; p2++)
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			nel >>= 1;
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		_DIAGASSERT(p2 <= MAX_BUCKETS_LG2);
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		nel = 1 << p2;
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	}
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	/* Allocate the table. */
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	htablesize = nel;
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	htable = calloc(htablesize, sizeof htable[0]);
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	if (htable == NULL) {
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		errno = ENOMEM;
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		return 0;
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	}
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	/* Initialize it. */
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	for (idx = 0; idx < htablesize; idx++)
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		SLIST_INIT(&htable[idx]);
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	return 1;
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}
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void
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hdestroy(void)
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{
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	struct internal_entry *ie;
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	size_t idx;
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	_DIAGASSERT(htable != NULL);
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	if (htable == NULL)
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		return;
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	for (idx = 0; idx < htablesize; idx++) {
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		while (!SLIST_EMPTY(&htable[idx])) {
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			ie = SLIST_FIRST(&htable[idx]);
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			SLIST_REMOVE_HEAD(&htable[idx], link);
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			free(ie->ent.key);
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			free(ie);
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		}
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	}
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	free(htable);
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	htable = NULL;
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}
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ENTRY *
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hsearch(ENTRY item, ACTION action)
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{
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	struct internal_head *head;
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	struct internal_entry *ie;
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	uint32_t hashval;
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	size_t len;
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	_DIAGASSERT(htable != NULL);
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	_DIAGASSERT(item.key != NULL);
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	_DIAGASSERT(action == ENTER || action == FIND);
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	len = strlen(item.key);
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	hashval = __default_hash(item.key, len);
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	head = &htable[hashval & (htablesize - 1)];
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	ie = SLIST_FIRST(head);
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	while (ie != NULL) {
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		if (strcmp(ie->ent.key, item.key) == 0)
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			break;
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		ie = SLIST_NEXT(ie, link);
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	}
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	if (ie != NULL)
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		return &ie->ent;
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	else if (action == FIND)
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		return NULL;
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	ie = malloc(sizeof *ie);
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	if (ie == NULL)
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		return NULL;
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	ie->ent.key = item.key;
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	ie->ent.data = item.data;
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	SLIST_INSERT_HEAD(head, ie, link);
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	return &ie->ent;
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}