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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libc/] [search/] [hcreate_r.c] - Rev 855
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/* $NetBSD: hcreate.c,v 1.2 2001/02/19 21:26:04 ross Exp $ */ /* * Copyright (c) 2001 Christopher G. Demetriou * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * <<Id: LICENSE_GC,v 1.1 2001/10/01 23:24:05 cgd Exp>> */ /* * hcreate() / hsearch() / hdestroy() * * SysV/XPG4 hash table functions. * * Implementation done based on NetBSD manual page and Solaris manual page, * plus my own personal experience about how they're supposed to work. * * I tried to look at Knuth (as cited by the Solaris manual page), but * nobody had a copy in the office, so... */ #include <sys/cdefs.h> #if 0 #if defined(LIBC_SCCS) && !defined(lint) __RCSID("$NetBSD: hcreate.c,v 1.2 2001/02/19 21:26:04 ross Exp $"); #endif /* LIBC_SCCS and not lint */ #endif #include <sys/types.h> #include <sys/queue.h> #include <errno.h> #include <search.h> #include <stdlib.h> #include <string.h> /* * DO NOT MAKE THIS STRUCTURE LARGER THAN 32 BYTES (4 ptrs on 64-bit * ptr machine) without adjusting MAX_BUCKETS_LG2 below. */ struct internal_entry { SLIST_ENTRY(internal_entry) link; ENTRY ent; }; SLIST_HEAD(internal_head, internal_entry); #define MIN_BUCKETS_LG2 4 #define MIN_BUCKETS (1 << MIN_BUCKETS_LG2) /* * max * sizeof internal_entry must fit into size_t. * assumes internal_entry is <= 32 (2^5) bytes. */ #define MAX_BUCKETS_LG2 (sizeof (size_t) * 8 - 1 - 5) #define MAX_BUCKETS ((size_t)1 << MAX_BUCKETS_LG2) /* Default hash function, from db/hash/hash_func.c */ extern __uint32_t (*__default_hash)(const void *, size_t); int hcreate_r(size_t nel, struct hsearch_data *htab) { size_t idx; unsigned int p2; /* Make sure this this isn't called when a table already exists. */ if (htab->htable != NULL) { errno = EINVAL; return 0; } /* If nel is too small, make it min sized. */ if (nel < MIN_BUCKETS) nel = MIN_BUCKETS; /* If it's too large, cap it. */ if (nel > MAX_BUCKETS) nel = MAX_BUCKETS; /* If it's is not a power of two in size, round up. */ if ((nel & (nel - 1)) != 0) { for (p2 = 0; nel != 0; p2++) nel >>= 1; nel = 1 << p2; } /* Allocate the table. */ htab->htablesize = nel; htab->htable = malloc(htab->htablesize * sizeof htab->htable[0]); if (htab->htable == NULL) { errno = ENOMEM; return 0; } /* Initialize it. */ for (idx = 0; idx < htab->htablesize; idx++) SLIST_INIT(&(htab->htable[idx])); return 1; } void hdestroy_r(struct hsearch_data *htab) { struct internal_entry *ie; size_t idx; if (htab->htable == NULL) return; #if 0 for (idx = 0; idx < htab->htablesize; idx++) { while (!SLIST_EMPTY(&(htab->htable[idx]))) { ie = SLIST_FIRST(&(htab->htable[idx])); SLIST_REMOVE_HEAD(&(htab->htable[idx]), link); free(ie->ent.key); free(ie); } } #endif free(htab->htable); htab->htable = NULL; } int hsearch_r(ENTRY item, ACTION action, ENTRY **retval, struct hsearch_data *htab) { struct internal_head *head; struct internal_entry *ie; __uint32_t hashval; size_t len; len = strlen(item.key); hashval = (*__default_hash)(item.key, len); head = &(htab->htable[hashval & (htab->htablesize - 1)]); ie = SLIST_FIRST(head); while (ie != NULL) { if (strcmp(ie->ent.key, item.key) == 0) break; ie = SLIST_NEXT(ie, link); } if (ie != NULL) { *retval = &ie->ent; return 1; } else if (action == FIND) { *retval = NULL; return 0; } ie = malloc(sizeof *ie); if (ie == NULL) { *retval = NULL; return 0; } ie->ent.key = item.key; ie->ent.data = item.data; SLIST_INSERT_HEAD(head, ie, link); *retval = &ie->ent; return 1; }
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