diff options
Diffstat (limited to 'devel/bmake/files/hash.c')
| -rw-r--r-- | devel/bmake/files/hash.c | 463 |
1 files changed, 463 insertions, 0 deletions
diff --git a/devel/bmake/files/hash.c b/devel/bmake/files/hash.c new file mode 100644 index 00000000000..f44222ca5f7 --- /dev/null +++ b/devel/bmake/files/hash.c @@ -0,0 +1,463 @@ +/* $NetBSD: hash.c,v 1.1 2005/10/31 21:34:24 reed Exp $ */ + +/* + * Copyright (c) 1988, 1989, 1990 The Regents of the University of California. + * All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Adam de Boor. + * + * 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. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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. + */ + +/* + * Copyright (c) 1988, 1989 by Adam de Boor + * Copyright (c) 1989 by Berkeley Softworks + * All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Adam de Boor. + * + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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. + */ + +#ifndef MAKE_NATIVE +static char rcsid[] = "$NetBSD: hash.c,v 1.1 2005/10/31 21:34:24 reed Exp $"; +#else +#include <sys/cdefs.h> +#ifndef lint +#if 0 +static char sccsid[] = "@(#)hash.c 8.1 (Berkeley) 6/6/93"; +#else +__RCSID("$NetBSD: hash.c,v 1.1 2005/10/31 21:34:24 reed Exp $"); +#endif +#endif /* not lint */ +#endif + +/* hash.c -- + * + * This module contains routines to manipulate a hash table. + * See hash.h for a definition of the structure of the hash + * table. Hash tables grow automatically as the amount of + * information increases. + */ +#include "sprite.h" +#include "make.h" +#include "hash.h" + +/* + * Forward references to local procedures that are used before they're + * defined: + */ + +static void RebuildTable(Hash_Table *); + +/* + * The following defines the ratio of # entries to # buckets + * at which we rebuild the table to make it larger. + */ + +#define rebuildLimit 3 + +/* + *--------------------------------------------------------- + * + * Hash_InitTable -- + * + * This routine just sets up the hash table. + * + * Input: + * t Structure to to hold table. + * numBuckets How many buckets to create for starters. This + * number is rounded up to a power of two. If + * <= 0, a reasonable default is chosen. The + * table will grow in size later as needed. + * + * Results: + * None. + * + * Side Effects: + * Memory is allocated for the initial bucket area. + * + *--------------------------------------------------------- + */ + +void +Hash_InitTable(Hash_Table *t, int numBuckets) +{ + int i; + struct Hash_Entry **hp; + + /* + * Round up the size to a power of two. + */ + if (numBuckets <= 0) + i = 16; + else { + for (i = 2; i < numBuckets; i <<= 1) + continue; + } + t->numEntries = 0; + t->size = i; + t->mask = i - 1; + t->bucketPtr = hp = emalloc(sizeof(*hp) * i); + while (--i >= 0) + *hp++ = NULL; +} + +/* + *--------------------------------------------------------- + * + * Hash_DeleteTable -- + * + * This routine removes everything from a hash table + * and frees up the memory space it occupied (except for + * the space in the Hash_Table structure). + * + * Results: + * None. + * + * Side Effects: + * Lots of memory is freed up. + * + *--------------------------------------------------------- + */ + +void +Hash_DeleteTable(Hash_Table *t) +{ + struct Hash_Entry **hp, *h, *nexth = NULL; + int i; + + for (hp = t->bucketPtr, i = t->size; --i >= 0;) { + for (h = *hp++; h != NULL; h = nexth) { + nexth = h->next; + free(h); + } + } + free(t->bucketPtr); + + /* + * Set up the hash table to cause memory faults on any future access + * attempts until re-initialization. + */ + t->bucketPtr = NULL; +} + +/* + *--------------------------------------------------------- + * + * Hash_FindEntry -- + * + * Searches a hash table for an entry corresponding to key. + * + * Input: + * t Hash table to search. + * key A hash key. + * + * Results: + * The return value is a pointer to the entry for key, + * if key was present in the table. If key was not + * present, NULL is returned. + * + * Side Effects: + * None. + * + *--------------------------------------------------------- + */ + +Hash_Entry * +Hash_FindEntry(Hash_Table *t, const char *key) +{ + Hash_Entry *e; + unsigned h; + const char *p; + + for (h = 0, p = key; *p;) + h = (h << 5) - h + *p++; + p = key; + for (e = t->bucketPtr[h & t->mask]; e != NULL; e = e->next) + if (e->namehash == h && strcmp(e->name, p) == 0) + return (e); + return (NULL); +} + +/* + *--------------------------------------------------------- + * + * Hash_CreateEntry -- + * + * Searches a hash table for an entry corresponding to + * key. If no entry is found, then one is created. + * + * Input: + * t Hash table to search. + * key A hash key. + * newPtr Filled in with TRUE if new entry created, + * FALSE otherwise. + * + * Results: + * The return value is a pointer to the entry. If *newPtr + * isn't NULL, then *newPtr is filled in with TRUE if a + * new entry was created, and FALSE if an entry already existed + * with the given key. + * + * Side Effects: + * Memory may be allocated, and the hash buckets may be modified. + *--------------------------------------------------------- + */ + +Hash_Entry * +Hash_CreateEntry(Hash_Table *t, const char *key, Boolean *newPtr) +{ + Hash_Entry *e; + unsigned h; + const char *p; + int keylen; + struct Hash_Entry **hp; + + /* + * Hash the key. As a side effect, save the length (strlen) of the + * key in case we need to create the entry. + */ + for (h = 0, p = key; *p;) + h = (h << 5) - h + *p++; + keylen = p - key; + p = key; + for (e = t->bucketPtr[h & t->mask]; e != NULL; e = e->next) { + if (e->namehash == h && strcmp(e->name, p) == 0) { + if (newPtr != NULL) + *newPtr = FALSE; + return (e); + } + } + + /* + * The desired entry isn't there. Before allocating a new entry, + * expand the table if necessary (and this changes the resulting + * bucket chain). + */ + if (t->numEntries >= rebuildLimit * t->size) + RebuildTable(t); + e = emalloc(sizeof(*e) + keylen); + hp = &t->bucketPtr[h & t->mask]; + e->next = *hp; + *hp = e; + e->clientData = NULL; + e->namehash = h; + (void)strcpy(e->name, p); + t->numEntries++; + + if (newPtr != NULL) + *newPtr = TRUE; + return (e); +} + +/* + *--------------------------------------------------------- + * + * Hash_DeleteEntry -- + * + * Delete the given hash table entry and free memory associated with + * it. + * + * Results: + * None. + * + * Side Effects: + * Hash chain that entry lives in is modified and memory is freed. + * + *--------------------------------------------------------- + */ + +void +Hash_DeleteEntry(Hash_Table *t, Hash_Entry *e) +{ + Hash_Entry **hp, *p; + + if (e == NULL) + return; + for (hp = &t->bucketPtr[e->namehash & t->mask]; + (p = *hp) != NULL; hp = &p->next) { + if (p == e) { + *hp = p->next; + free(p); + t->numEntries--; + return; + } + } + (void)write(2, "bad call to Hash_DeleteEntry\n", 29); + abort(); +} + +/* + *--------------------------------------------------------- + * + * Hash_EnumFirst -- + * This procedure sets things up for a complete search + * of all entries recorded in the hash table. + * + * Input: + * t Table to be searched. + * searchPtr Area in which to keep state about search. + * + * Results: + * The return value is the address of the first entry in + * the hash table, or NULL if the table is empty. + * + * Side Effects: + * The information in searchPtr is initialized so that successive + * calls to Hash_Next will return successive HashEntry's + * from the table. + * + *--------------------------------------------------------- + */ + +Hash_Entry * +Hash_EnumFirst(Hash_Table *t, Hash_Search *searchPtr) +{ + searchPtr->tablePtr = t; + searchPtr->nextIndex = 0; + searchPtr->hashEntryPtr = NULL; + return Hash_EnumNext(searchPtr); +} + +/* + *--------------------------------------------------------- + * + * Hash_EnumNext -- + * This procedure returns successive entries in the hash table. + * + * Input: + * searchPtr Area used to keep state about search. + * + * Results: + * The return value is a pointer to the next HashEntry + * in the table, or NULL when the end of the table is + * reached. + * + * Side Effects: + * The information in searchPtr is modified to advance to the + * next entry. + * + *--------------------------------------------------------- + */ + +Hash_Entry * +Hash_EnumNext(Hash_Search *searchPtr) +{ + Hash_Entry *e; + Hash_Table *t = searchPtr->tablePtr; + + /* + * The hashEntryPtr field points to the most recently returned + * entry, or is nil if we are starting up. If not nil, we have + * to start at the next one in the chain. + */ + e = searchPtr->hashEntryPtr; + if (e != NULL) + e = e->next; + /* + * If the chain ran out, or if we are starting up, we need to + * find the next nonempty chain. + */ + while (e == NULL) { + if (searchPtr->nextIndex >= t->size) + return (NULL); + e = t->bucketPtr[searchPtr->nextIndex++]; + } + searchPtr->hashEntryPtr = e; + return (e); +} + +/* + *--------------------------------------------------------- + * + * RebuildTable -- + * This local routine makes a new hash table that + * is larger than the old one. + * + * Results: + * None. + * + * Side Effects: + * The entire hash table is moved, so any bucket numbers + * from the old table are invalid. + * + *--------------------------------------------------------- + */ + +static void +RebuildTable(Hash_Table *t) +{ + Hash_Entry *e, *next = NULL, **hp, **xp; + int i, mask; + Hash_Entry **oldhp; + int oldsize; + + oldhp = t->bucketPtr; + oldsize = i = t->size; + i <<= 1; + t->size = i; + t->mask = mask = i - 1; + t->bucketPtr = hp = emalloc(sizeof(*hp) * i); + while (--i >= 0) + *hp++ = NULL; + for (hp = oldhp, i = oldsize; --i >= 0;) { + for (e = *hp++; e != NULL; e = next) { + next = e->next; + xp = &t->bucketPtr[e->namehash & mask]; + e->next = *xp; + *xp = e; + } + } + free(oldhp); +} |