move the ohash functions into libutil by popular demand.

It's not a standard interface, so it doesn't belong in libc.
I hate duplicating the code in client programs, so do beck@, kettenis@,
schwarze@, millert@, miod@... and they agree with libutil.

src/include/Makefile

@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.189 2014/04/22 10:21:56 reyk Exp $
+#	$OpenBSD: Makefile,v 1.190 2014/05/12 19:09:00 espie Exp $
 #	$NetBSD: Makefile,v 1.59 1996/05/15 21:36:43 jtc Exp $
 
 #	@(#)Makefile	5.45.1.1 (Berkeley) 5/6/91
@@ -15,7 +15,7 @@ FILES=	a.out.h ar.h asr.h assert.h bitstring.h blf.h bsd_auth.h \
 	ftw.h getopt.h glob.h grp.h ifaddrs.h inttypes.h iso646.h kvm.h \
 	langinfo.h libgen.h limits.h locale.h login_cap.h malloc.h math.h \
 	md5.h memory.h mpool.h ndbm.h netdb.h netgroup.h nlist.h nl_types.h \
-	ohash.h paths.h poll.h pwd.h ranlib.h readpassphrase.h regex.h \
+	paths.h poll.h pwd.h ranlib.h readpassphrase.h regex.h \
 	resolv.h rmd160.h search.h setjmp.h sha1.h sha2.h signal.h sndio.h \
 	spawn.h stdbool.h stddef.h stdio.h stdlib.h string.h strings.h struct.h \
 	sysexits.h tar.h tgmath.h time.h ttyent.h tzfile.h unistd.h utime.h \

src/lib/libutil/Makefile

@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.36 2013/06/03 21:07:02 tedu Exp $
+#	$OpenBSD: Makefile,v 1.37 2014/05/12 19:09:00 espie Exp $
 #	$NetBSD: Makefile,v 1.8 1996/05/16 07:03:28 thorpej Exp $
 
 LIB=	util
@@ -60,6 +60,26 @@ MLINKS+=uucplock.3 uu_lockerr.3
 MLINKS+=uucplock.3 uu_lock_txfr.3
 MLINKS+=fmt_scaled.3 scan_scaled.3
 
+SRCS+=	ohash_create_entry.c ohash_delete.c ohash_do.c ohash_entries.c \
+	ohash_enum.c ohash_init.c ohash_interval.c \
+	ohash_lookup_interval.c ohash_lookup_memory.c \
+	ohash_qlookup.c ohash_qlookupi.c
+
+MAN +=	ohash_init.3 ohash_interval.3
+MLINKS += ohash_init.3 ohash_delete.3 \
+	ohash_init.3 ohash_lookup_interval.3 \
+	ohash_init.3 ohash_lookup_memory.3 \
+	ohash_init.3 ohash_find.3 \
+	ohash_init.3 ohash_remove.3 \
+	ohash_init.3 ohash_insert.3 \
+	ohash_init.3 ohash_first.3 \
+	ohash_init.3 ohash_next.3 \
+	ohash_init.3 ohash_entries.3 \
+	ohash_interval.3 ohash_create_entry.3 \
+	ohash_interval.3 ohash_qlookupi.3 \
+	ohash_interval.3 ohash_qlookup.3
+HDRS += ohash.h
+
 includes:
 	@cd ${.CURDIR}; for i in $(HDRS); do \
 	    j="cmp -s $$i ${DESTDIR}/usr/include/$$i || \

src/lib/libutil/ohash.h

@@ -0,0 +1,75 @@
+#ifndef OHASH_H
+#define OHASH_H
+/* $OpenBSD: ohash.h,v 1.1 2014/05/12 19:09:00 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.
+ */
+
+/* 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

src/lib/libutil/ohash_create_entry.c

@@ -0,0 +1,38 @@
+/* $OpenBSD: ohash_create_entry.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+
+/* This handles the common case of variable length keys, where the 
+ * key is stored at the end of the record.
+ */
+void *
+ohash_create_entry(struct ohash_info *i, const char *start, const char **end)
+{
+	char *p;
+
+	if (!*end)
+		*end = start + strlen(start);
+	p = (i->alloc)(i->key_offset + (*end - start) + 1, i->data);
+	if (p) {
+	    memcpy(p+i->key_offset, start, *end-start);
+	    p[i->key_offset + (*end - start)] = '\0';
+	}
+	return (void *)p;
+}

src/lib/libutil/ohash_delete.c

@@ -0,0 +1,30 @@
+/* $OpenBSD: ohash_delete.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+/* hash_delete only frees the hash structure. Use hash_first/hash_next
+ * to free entries as well.  */
+void 
+ohash_delete(struct ohash *h)
+{
+	(h->info.free)(h->t, h->info.data);
+#ifndef NDEBUG
+	h->t = NULL;
+#endif
+}

src/lib/libutil/ohash_do.c

@@ -0,0 +1,116 @@
+/* $OpenBSD: ohash_do.c,v 1.1 2014/05/12 19:09:00 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 <limits.h>
+#include "ohash_int.h"
+
+static void ohash_resize(struct ohash *);
+
+static void 
+ohash_resize(struct ohash *h)
+{
+	struct _ohash_record *n;
+	size_t ns;
+	unsigned int 	j;
+	unsigned int	i, incr;
+
+	if (4 * h->deleted < h->total) {
+		if (h->size >= (UINT_MAX >> 1U))
+			ns = UINT_MAX;
+		else
+			ns = h->size << 1U;
+	} else if (3 * h->deleted > 2 * h->total)
+		ns = h->size >> 1U;
+	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.calloc)(ns, sizeof(struct _ohash_record), 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.free)(h->t, 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 = (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 (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;
+}

src/lib/libutil/ohash_entries.c

@@ -0,0 +1,26 @@
+/* $OpenBSD: ohash_entries.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+
+unsigned int
+ohash_entries(struct ohash *h)
+{
+	return h->total - h->deleted;
+}

src/lib/libutil/ohash_enum.c

@@ -0,0 +1,36 @@
+/* $OpenBSD: ohash_enum.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+
+void *
+ohash_first(struct ohash *h, unsigned int *pos)
+{
+	*pos = 0;
+	return ohash_next(h, pos);
+}
+	
+void *
+ohash_next(struct ohash *h, unsigned int *pos)
+{
+	for (; *pos < h->size; (*pos)++) 
+		if (h->t[*pos].p != DELETED && h->t[*pos].p != NULL) 
+			return (void *)h->t[(*pos)++].p;
+	return NULL;
+}

src/lib/libutil/ohash_init.3

@@ -0,0 +1,271 @@
+.\"	$OpenBSD: ohash_init.3,v 1.1 2014/05/12 19:09:00 espie Exp $
+.\" Copyright (c) 1999 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.
+.\"
+.Dd $Mdocdate: May 12 2014 $
+.Dt OHASH_INIT 3
+.Os
+.Sh NAME
+.Nm ohash_init ,
+.Nm ohash_delete ,
+.Nm ohash_lookup_interval ,
+.Nm ohash_lookup_memory ,
+.Nm ohash_find ,
+.Nm ohash_remove ,
+.Nm ohash_insert ,
+.Nm ohash_first ,
+.Nm ohash_next ,
+.Nm ohash_entries
+.Nd light-weight open hashing
+.Sh SYNOPSIS
+.In stdint.h
+.In stddef.h
+.In ohash.h
+.Ft void
+.Fn ohash_init "struct ohash *h" "unsigned int size" "struct ohash_info *info"
+.Ft void
+.Fn ohash_delete "struct ohash *h"
+.Ft "unsigned int"
+.Fn ohash_lookup_interval "struct ohash *h" "const char *start" "const char *end" "uint32_t hv"
+.Ft "unsigned int"
+.Fn ohash_lookup_memory "struct ohash *h" "const char *k" "size_t s" "uint32_t hv"
+.Ft void *
+.Fn ohash_find "struct ohash *h" "unsigned int i"
+.Ft void *
+.Fn ohash_remove "struct ohash *h" "unsigned int i"
+.Ft void *
+.Fn ohash_insert "struct ohash *h" "unsigned int i" "void *p"
+.Ft void *
+.Fn ohash_first "struct ohash *h" "unsigned int *i"
+.Ft void *
+.Fn ohash_next "struct ohash *h" "unsigned int *i"
+.Ft "unsigned int"
+.Fn ohash_entries "struct ohash *h"
+.Sh DESCRIPTION
+These functions have been designed as a fast, extensible alternative to
+the usual hash table functions.
+They provide storage and retrieval of records indexed by keys,
+where a key is a contiguous sequence of bytes at a fixed position in
+each record.
+Keys can either be NUL-terminated strings or fixed-size memory areas.
+All functions take a pointer to an ohash structure as the
+.Fa h
+function argument.
+Storage for this structure should be provided by user code.
+.Pp
+.Fn ohash_init
+initializes the table to store roughly 2 to the power
+.Fa size
+elements.
+.Fa info
+is a pointer to a
+.Fa struct ohash_info .
+.Bd -literal -offset indent
+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 *);
+};
+.Ed
+.Pp
+The
+.Va offset
+field holds the position of the key in each record;
+the
+.Va calloc
+and
+.Va free
+fields are pointers to 
+.Xr calloc 3
+and
+.Xr free 3 Ns -like
+functions, used for managing the table internal storage;
+the
+.Va alloc
+field is only used by the utility function
+.Xr ohash_create_entry 3 .
+.Pp
+Each of these functions are called similarly to their standard counterpart,
+but with an extra 
+.Ft void *
+parameter corresponding to the content of the field
+.Fa data ,
+which can be used to communicate specific information to the functions.
+.Pp
+.Fn ohash_init
+stores a copy of those fields internally, so
+.Fa info
+can be reclaimed after initialization.
+.Pp
+.Fn ohash_delete
+frees storage internal to
+.Fa h .
+Elements themselves should be freed by the user first, using for instance
+.Fn ohash_first
+and
+.Fn ohash_next .
+.Pp
+.Fn ohash_lookup_interval
+and
+.Fn ohash_lookup_memory
+are the basic look-up element functions.
+The hashing function result is provided by the user as
+.Fa hv .
+These return a
+.Qq slot
+in the ohash table
+.Fa h ,
+to be used with
+.Fn ohash_find ,
+.Fn ohash_insert ,
+or
+.Fn ohash_remove .
+This slot is only valid up to the next call to
+.Fn ohash_insert
+or
+.Fn ohash_remove .
+.Pp
+.Fn ohash_lookup_interval
+handles string-like keys.
+.Fn ohash_lookup_interval
+assumes the key is the interval between
+.Fa start
+and
+.Fa end ,
+exclusive,
+though the actual elements stored in the table should only contain
+NUL-terminated keys.
+.Pp
+.Fn ohash_lookup_memory
+assumes the key is the memory area starting at
+.Fa k
+of size
+.Fa s .
+All bytes are significant in key comparison.
+.Pp
+.Fn ohash_find
+retrieves an element from a slot
+.Fa i
+returned by the
+.Fn ohash_lookup*
+functions.
+It returns
+.Dv NULL
+if the slot is empty.
+.Pp
+.Fn ohash_insert
+inserts a new element
+.Fa p
+at slot
+.Fa i .
+Slot
+.Fa i
+must be empty and element
+.Fa p
+must have a key corresponding to the
+.Fn ohash_lookup*
+call.
+.Pp
+.Fn ohash_remove
+removes the element at slot
+.Fa i .
+It returns the removed element, for user code to dispose of, or
+.Dv NULL
+if the slot was empty.
+.Pp
+.Fn ohash_first
+and
+.Fn ohash_next
+can be used to access all elements in an ohash table, like this:
+.Bd -literal -offset indent
+for (n = ohash_first(h, &i); n != NULL; n = ohash_next(h, &i))
+	do_something_with(n);
+.Ed
+.Pp
+.Fa i
+points to an auxiliary unsigned integer used to record the current position
+in the ohash table.
+Those functions are safe to use even while entries are added to/removed
+from the table, but in such a case they don't guarantee that new entries
+will be returned.
+As a special case, they can safely be used to free elements in the table.
+.Pp
+.Fn ohash_entries
+returns the number of elements in the hash table.
+.Sh STORAGE HANDLING
+Only
+.Fn ohash_init ,
+.Fn ohash_insert ,
+.Fn ohash_remove
+and
+.Fn ohash_delete
+may call the user-supplied memory functions:
+.Bd -literal -offset indent
+p = (*info->calloc)(n, sizeof_record, info->data);
+/* copy data from old to p */
+(*info->free)(old, info->data);
+.Ed
+.Pp
+It is the responsibility of the user memory allocation code to verify
+that those calls did not fail.
+.Pp
+If memory allocation fails,
+.Fn ohash_init
+returns a useless hash table.
+.Fn ohash_insert
+and
+.Fn ohash_remove
+still perform the requested operation, but the returned table should be
+considered read-only.
+It can still be accessed by
+.Fn ohash_lookup* ,
+.Fn ohash_find ,
+.Fn ohash_first
+and
+.Fn ohash_next
+to dump relevant information to disk before aborting.
+.Sh THREAD SAFETY
+The open hashing functions are not thread-safe by design.
+In particular, in a threaded environment, there is no guarantee that a
+.Qq slot
+will not move between a
+.Fn ohash_lookup*
+and a
+.Fn ohash_find ,
+.Fn ohash_insert
+or
+.Fn ohash_remove
+call.
+.Pp
+Multi-threaded applications should explicitly protect ohash table access.
+.Sh SEE ALSO
+.Xr hcreate 3 ,
+.Xr ohash_interval 3
+.Rs
+.%A Donald E. Knuth
+.%B The Art of Computer Programming
+.%V Vol. 3
+.%P pp 506-550
+.%D 1973
+.Re
+.Sh STANDARDS
+Those functions are completely non-standard and should be avoided in
+portable programs.
+.Sh HISTORY
+Those functions were designed and written for
+.Ox
+.Xr make 1
+by Marc Espie in 1999.

src/lib/libutil/ohash_init.c

@@ -0,0 +1,41 @@
+/* $OpenBSD: ohash_init.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+
+void 
+ohash_init(struct ohash *h, unsigned int size, struct ohash_info *info)
+{
+	h->size = 1UL << size;
+	if (h->size < MINSIZE)
+		h->size = MINSIZE;
+#ifdef STATS_HASH
+	STAT_HASH_CREATION++;
+	STAT_HASH_SIZE += h->size;
+#endif
+	/* Copy info so that caller may free it.  */
+	h->info.key_offset = info->key_offset;
+	h->info.calloc = info->calloc;
+	h->info.free = info->free;
+	h->info.alloc = info->alloc;
+	h->info.data = info->data;
+	h->t = (h->info.calloc)(h->size, sizeof(struct _ohash_record),
+		    h->info.data);
+	h->total = h->deleted = 0;
+}

src/lib/libutil/ohash_int.h

@@ -0,0 +1,19 @@
+/*	$OpenBSD: ohash_int.h,v 1.1 2014/05/12 19:09:00 espie Exp $	*/
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include "ohash.h"
+
+struct _ohash_record {
+	uint32_t	hv;
+	const char 	*p;
+};
+
+#define DELETED		((const char *)h)
+#define NONE		(h->size)
+
+/* Don't bother changing the hash table if the change is small enough.  */
+#define MINSIZE		(1UL << 4)
+#define MINDELETED	4

src/lib/libutil/ohash_interval.3

@@ -0,0 +1,93 @@
+.\"	$OpenBSD: ohash_interval.3,v 1.1 2014/05/12 19:09:00 espie Exp $
+.\" Copyright (c) 2001 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.
+.\"
+.Dd $Mdocdate: May 12 2014 $
+.Dt OHASH_INTERVAL 3
+.Os
+.Sh NAME
+.Nm ohash_interval ,
+.Nm ohash_create_entry ,
+.Nm ohash_qlookup ,
+.Nm ohash_qlookupi
+.Nd helper functions for open hashing
+.Sh SYNOPSIS
+.In stdint.h
+.In stddef.h
+.In ohash.h
+.Ft uint32_t
+.Fn ohash_interval "const char *start" "const char **pend"
+.Ft "void *"
+.Fn ohash_create_entry "struct ohash_info *info" "const char *start" "const char **pend"
+.Ft "unsigned int"
+.Fn ohash_qlookupi "struct ohash *h" "const char *start" "const char **pend"
+.Ft "unsigned int"
+.Fn ohash_qlookup "struct ohash *h" "const char *start"
+.Sh DESCRIPTION
+These functions are commonly used to simplify open hashing usage, and use
+similar conventions.
+They operate indifferently on NUL-terminated strings
+.Po
+by setting
+.Fa *pend
+=
+.Dv NULL
+.Pc
+or memory ranges
+.Po
+delimited by
+.Fa start
+and
+.Fa *pend
+.Pc .
+For NUL-terminated strings, as a side effect, those functions
+set
+.Fa *pend
+to the terminating NUL byte.
+.Pp
+.Fn ohash_interval
+is a simple hashing function that yields good results on common data sets.
+.Pp
+.Fn ohash_create_entry
+can be used to create a new record with a given key.
+In that case,
+the alloc field of
+.Fa info
+should point to a
+.Xr malloc 3 Ns -like
+function to allocate the storage:
+.Bd -literal -offset indent
+p = (*info->alloc)(sz, info->data);
+.Ed
+.Pp
+.Fn ohash_qlookupi
+is a wrapper function that simply calls
+.Fn ohash_interval
+and
+.Fn ohash_lookup_interval .
+.Pp
+.Fn ohash_qlookup
+is a variation on
+.Fn ohash_qlookupi
+designed for NUL-terminated strings.
+.Sh SEE ALSO
+.Xr ohash_init 3
+.Sh STANDARDS
+Those functions are completely non-standard and should be avoided in
+portable programs.
+.Sh HISTORY
+Those functions were designed and written for
+.Ox
+.Xr make 1
+by Marc Espie in 1999.

src/lib/libutil/ohash_interval.c

@@ -0,0 +1,36 @@
+/* $OpenBSD: ohash_interval.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+
+uint32_t
+ohash_interval(const char *s, const char **e)
+{
+	uint32_t k;
+
+	if (!*e)
+		*e = s + strlen(s);
+	if (s == *e)
+		k = 0;
+	else
+		k = *s++;
+	while (s != *e)
+		k =  ((k << 2) | (k >> 30)) ^ *s++;
+	return k;
+}

src/lib/libutil/ohash_lookup_interval.c

@@ -0,0 +1,68 @@
+/* $OpenBSD: ohash_lookup_interval.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+	
+unsigned int
+ohash_lookup_interval(struct ohash *h, const char *start, const char *end, 
+    uint32_t hv)
+{
+	unsigned int 	i, incr;
+	unsigned int	empty;
+	
+#ifdef STATS_HASH
+	STAT_HASH_LOOKUP++;
+#endif
+	empty = NONE;
+	i = hv % h->size;
+	incr = ((hv % (h->size-2)) & ~1) + 1;
+	while (h->t[i].p != NULL) {
+#ifdef STATS_HASH
+		STAT_HASH_LENGTH++;
+#endif
+		if (h->t[i].p == DELETED) {
+			if (empty == NONE)
+				empty = i;
+		} else if (h->t[i].hv == hv && 
+		    strncmp(h->t[i].p+h->info.key_offset, start, 
+		    	end - start) == 0 &&
+		    (h->t[i].p+h->info.key_offset)[end-start] == '\0') {
+		    	if (empty != NONE) {
+				h->t[empty].hv = hv;
+				h->t[empty].p = h->t[i].p;
+				h->t[i].p = DELETED;
+				return empty;
+			} else {
+#ifdef STATS_HASH
+				STAT_HASH_POSITIVE++;
+#endif
+				return i;
+			}
+		}
+		i += incr;
+		if (i >= h->size) 
+			i -= h->size;
+	}
+
+	/* Found an empty position.  */
+	if (empty != NONE) 
+		i = empty;
+	h->t[i].hv = hv;
+	return i;
+}

src/lib/libutil/ohash_lookup_memory.c

@@ -0,0 +1,64 @@
+/* $OpenBSD: ohash_lookup_memory.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+
+unsigned int
+ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
+{
+	unsigned int	i, incr;
+	unsigned int	empty;
+	
+#ifdef STATS_HASH
+	STAT_HASH_LOOKUP++;
+#endif
+	empty = NONE;
+	i = hv % h->size;
+	incr = ((hv % (h->size-2)) & ~1) + 1;
+	while (h->t[i].p != NULL) {
+#ifdef STATS_HASH
+		STAT_HASH_LENGTH++;
+#endif
+		if (h->t[i].p == DELETED) {
+			if (empty == NONE)
+				empty = i;
+		} else if (h->t[i].hv == hv && 
+		    memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
+		    	if (empty != NONE) {
+				h->t[empty].hv = hv;
+				h->t[empty].p = h->t[i].p;
+				h->t[i].p = DELETED;
+				return empty;
+			} else {
+#ifdef STATS_HASH
+				STAT_HASH_POSITIVE++;
+#endif
+			}	return i;
+		}
+		i += incr;
+		if (i >= h->size) 
+			i -= h->size;
+	}
+
+	/* Found an empty position.  */
+	if (empty != NONE) 
+		i = empty;
+	h->t[i].hv = hv;
+	return i;
+}

src/lib/libutil/ohash_qlookup.c

@@ -0,0 +1,27 @@
+/* $OpenBSD: ohash_qlookup.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+
+unsigned int
+ohash_qlookup(struct ohash *h, const char *s)
+{
+	const char *e = NULL;
+	return ohash_qlookupi(h, s, &e);
+}

src/lib/libutil/ohash_qlookupi.c

@@ -0,0 +1,29 @@
+/* $OpenBSD: ohash_qlookupi.c,v 1.1 2014/05/12 19:09:00 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 "ohash_int.h"
+
+unsigned int
+ohash_qlookupi(struct ohash *h, const char *s, const char **e)
+{
+	uint32_t hv;
+
+	hv = ohash_interval(s, e);
+	return ohash_lookup_interval(h, s, *e, hv);
+}

src/lib/libutil/shlib_version

@@ -1,2 +1,2 @@
 major=12
-minor=0
+minor=1