diff options
Diffstat (limited to 'usr.bin/m4/lib/ohash_do.c')
-rw-r--r-- | usr.bin/m4/lib/ohash_do.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/usr.bin/m4/lib/ohash_do.c b/usr.bin/m4/lib/ohash_do.c new file mode 100644 index 0000000..dffe6b6 --- /dev/null +++ b/usr.bin/m4/lib/ohash_do.c @@ -0,0 +1,113 @@ +/* $OpenBSD: ohash_do.c,v 1.4 2004/06/22 20:00:16 espie Exp $ */ +/* ex:ts=8 sw=4: + */ + +/* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "ohash_int.h" + +static void ohash_resize(struct ohash *); + +static void +ohash_resize(struct ohash *h) +{ + struct _ohash_record *n; + unsigned int ns, j; + unsigned int i, incr; + + if (4 * h->deleted < h->total) + ns = h->size << 1; + else if (3 * h->deleted > 2 * h->total) + ns = h->size >> 1; + else + ns = h->size; + if (ns < MINSIZE) + ns = MINSIZE; +#ifdef STATS_HASH + STAT_HASH_EXPAND++; + STAT_HASH_SIZE += ns - h->size; +#endif + n = (h->info.halloc)(sizeof(struct _ohash_record) * ns, h->info.data); + if (!n) + return; + + for (j = 0; j < h->size; j++) { + if (h->t[j].p != NULL && h->t[j].p != DELETED) { + i = h->t[j].hv % ns; + incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1; + while (n[i].p != NULL) { + i += incr; + if (i >= ns) + i -= ns; + } + n[i].hv = h->t[j].hv; + n[i].p = h->t[j].p; + } + } + (h->info.hfree)(h->t, sizeof(struct _ohash_record) * h->size, + h->info.data); + h->t = n; + h->size = ns; + h->total -= h->deleted; + h->deleted = 0; +} + +void * +ohash_remove(struct ohash *h, unsigned int i) +{ + void *result = __DECONST(void *, h->t[i].p); + + if (result == NULL || result == DELETED) + return NULL; + +#ifdef STATS_HASH + STAT_HASH_ENTRIES--; +#endif + h->t[i].p = DELETED; + h->deleted++; + if (h->deleted >= MINDELETED && 4 * h->deleted > h->total) + ohash_resize(h); + return result; +} + +void * +ohash_find(struct ohash *h, unsigned int i) +{ + if (h->t[i].p == DELETED) + return NULL; + else + return __DECONST(void *, h->t[i].p); +} + +void * +ohash_insert(struct ohash *h, unsigned int i, void *p) +{ +#ifdef STATS_HASH + STAT_HASH_ENTRIES++; +#endif + if (h->t[i].p == DELETED) { + h->deleted--; + h->t[i].p = p; + } else { + h->t[i].p = p; + /* Arbitrary resize boundary. Tweak if not efficient enough. */ + if (++h->total * 4 > h->size * 3) + ohash_resize(h); + } + return p; +} |