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diff --git a/lib/libutil/ohash.h b/lib/libutil/ohash.h
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+/* $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