134 lines
3.8 KiB
C
134 lines
3.8 KiB
C
Index: openbsd-compat/hash.h
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===================================================================
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RCS file: openbsd-compat/hash.h
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diff -N openbsd-compat/hash.h
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--- /dev/null 1 Jan 1970 00:00:00 -0000
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+++ openbsd-compat/hash.h 30 Jun 2009 05:48:11 -0000 1.1
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@@ -0,0 +1,127 @@
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+/* $OpenBSD: hash.h,v 1.4 2004/05/25 18:37:23 jmc Exp $ */
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+
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+/*
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+ * Copyright (c) 2001 Tobias Weingartner
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+ * All rights reserved.
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+ *
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+ * Redistribution and use in source and binary forms, with or without
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+ * modification, are permitted provided that the following conditions
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+ * are met:
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+ * 1. Redistributions of source code must retain the above copyright
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+ * notice, this list of conditions and the following disclaimer.
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+ * 2. Redistributions in binary form must reproduce the above copyright
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+ * notice, this list of conditions and the following disclaimer in the
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+ * documentation and/or other materials provided with the distribution.
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+ *
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+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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+ */
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+
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+#ifndef _SYS_HASH_H_
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+#define _SYS_HASH_H_
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+#include <sys/types.h>
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+
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+/*
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+ * Note: SMALL_KERNEL might be used to shrink these, right now I
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+ * do not see the point, as my kernel did not grow appreciably when
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+ * I switched to these from other inline code. This may have to be
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+ * revisited when/if these functions become more prevalent in the
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+ * kernel.
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+ */
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+
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+/* Convenience */
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+#ifndef HASHINIT
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+#define HASHINIT 5381
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+#define HASHSTEP(x,c) (((x << 5) + x) + (c))
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+#endif
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+
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+/*
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+ * Return a 32-bit hash of the given buffer. The init
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+ * value should be 0, or the previous hash value to extend
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+ * the previous hash.
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+ */
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+static __inline uint32_t
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+hash32_buf(const void *buf, size_t len, uint32_t hash)
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+{
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+ const unsigned char *p = buf;
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+
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+ while (len--)
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+ hash = HASHSTEP(hash, *p++);
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+
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+ return hash;
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+}
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+
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+/*
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+ * Return a 32-bit hash of the given string.
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+ */
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+static __inline uint32_t
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+hash32_str(const void *buf, uint32_t hash)
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+{
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+ const unsigned char *p = buf;
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+
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+ while (*p)
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+ hash = HASHSTEP(hash, *p++);
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+
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+ return hash;
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+}
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+
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+/*
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+ * Return a 32-bit hash of the given string, limited by N.
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+ */
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+static __inline uint32_t
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+hash32_strn(const void *buf, size_t len, uint32_t hash)
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+{
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+ const unsigned char *p = buf;
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+
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+ while (*p && len--)
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+ hash = HASHSTEP(hash, *p++);
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+
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+ return hash;
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+}
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+
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+/*
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+ * Return a 32-bit hash of the given string terminated by C,
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+ * (as well as 0). This is mainly here as a helper for the
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+ * namei() hashing of path name parts.
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+ */
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+static __inline uint32_t
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+hash32_stre(const void *buf, int end, char **ep, uint32_t hash)
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+{
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+ const unsigned char *p = buf;
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+
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+ while (*p && (*p != end))
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+ hash = HASHSTEP(hash, *p++);
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+
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+ if (ep)
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+ *ep = (char *)p;
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+
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+ return hash;
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+}
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+
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+/*
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+ * Return a 32-bit hash of the given string, limited by N,
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+ * and terminated by C (as well as 0). This is mainly here
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+ * as a helper for the namei() hashing of path name parts.
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+ */
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+static __inline uint32_t
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+hash32_strne(const void *buf, size_t len, int end, char **ep, uint32_t hash)
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+{
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+ const unsigned char *p = buf;
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+
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+ while (*p && (*p != end) && len--)
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+ hash = HASHSTEP(hash, *p++);
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+
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+ if (ep)
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+ *ep = (char *)p;
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+
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+ return hash;
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+}
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+#endif /* !_SYS_HASH_H_ */
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