diff options
Diffstat (limited to 'lib/libutil/ohash.h')
| -rw-r--r-- | lib/libutil/ohash.h | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/lib/libutil/ohash.h b/lib/libutil/ohash.h new file mode 100644 index 0000000..c5f81ec --- /dev/null +++ b/lib/libutil/ohash.h @@ -0,0 +1,74 @@ +/* $OpenBSD: ohash.h,v 1.2 2014/06/02 18:52:03 deraadt Exp $ */ + +/* 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. + */ + +#ifndef OHASH_H +#define OHASH_H + +/* Open hashing support. + * Open hashing was chosen because it is much lighter than other hash + * techniques, and more efficient in most cases. + */ + +/* user-visible data structure */ +struct ohash_info { + ptrdiff_t key_offset; + void *data; /* user data */ + void *(*calloc)(size_t, size_t, void *); + void (*free)(void *, void *); + void *(*alloc)(size_t, void *); +}; + +struct _ohash_record; + +/* private structure. It's there just so you can do a sizeof */ +struct ohash { + struct _ohash_record *t; + struct ohash_info info; + unsigned int size; + unsigned int total; + unsigned int deleted; +}; + +/* For this to be tweakable, we use small primitives, and leave part of the + * logic to the client application. e.g., hashing is left to the client + * application. We also provide a simple table entry lookup that yields + * a hashing table index (opaque) to be used in find/insert/remove. + * The keys are stored at a known position in the client data. + */ +__BEGIN_DECLS +void ohash_init(struct ohash *, unsigned, struct ohash_info *); +void ohash_delete(struct ohash *); + +unsigned int ohash_lookup_interval(struct ohash *, const char *, + const char *, uint32_t); +unsigned int ohash_lookup_memory(struct ohash *, const char *, + size_t, uint32_t) + __attribute__ ((__bounded__(__string__,2,3))); +void *ohash_find(struct ohash *, unsigned int); +void *ohash_remove(struct ohash *, unsigned int); +void *ohash_insert(struct ohash *, unsigned int, void *); +void *ohash_first(struct ohash *, unsigned int *); +void *ohash_next(struct ohash *, unsigned int *); +unsigned int ohash_entries(struct ohash *); + +void *ohash_create_entry(struct ohash_info *, const char *, const char **); +uint32_t ohash_interval(const char *, const char **); + +unsigned int ohash_qlookupi(struct ohash *, const char *, const char **); +unsigned int ohash_qlookup(struct ohash *, const char *); +__END_DECLS +#endif |