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+#=====================#
+# Fowler/Noll/Vo hash #
+#=====================#
+
+The basis of this hash algorithm was taken from an idea sent
+as reviewer comments to the IEEE POSIX P1003.2 committee by:
+
+     Phong Vo (http://www.research.att.com/info/kpv)
+     Glenn Fowler (http://www.research.att.com/~gsf/)
+
+In a subsequent ballot round:
+
+     Landon Curt Noll (http://www.isthe.com/chongo)
+
+improved on their algorithm.  Some people tried this hash
+and found that it worked rather well.  In an EMail message
+to Landon, they named it the ``Fowler/Noll/Vo'' or FNV hash.
+
+FNV hashes are designed to be fast while maintaining a low
+collision rate. The FNV speed allows one to quickly hash lots
+of data while maintaining a reasonable collision rate.  See:
+
+     http://www.isthe.com/chongo/tech/comp/fnv/index.html
+
+for more details as well as other forms of the FNV hash.
+Comments, questions, bug fixes and suggestions welcome at
+the address given in the above URL.
+
+
+#==================#
+# FNV hash utility #
+#==================#
+
+Two hash utilities (32 bit and 64 bit) are provided:
+
+	fnv032 [-b bcnt] [-m] [-s arg] [-t code] [-v] [arg ...]
+	fnv132 [-b bcnt] [-m] [-s arg] [-t code] [-v] [arg ...]
+	fnv1a32 [-b bcnt] [-m] [-s arg] [-t code] [-v] [arg ...]
+
+	fnv064 [-b bcnt] [-m] [-s arg] [-t code] [-v] [arg ...]
+	fnv164 [-b bcnt] [-m] [-s arg] [-t code] [-v] [arg ...]
+	fnv1a64 [-b bcnt] [-m] [-s arg] [-t code] [-v] [arg ...]
+
+	-b bcnt	  mask off all but the lower bcnt bits (default: 32)
+ 	-m	  multiple hashes, one per line for each arg
+	-s	  hash arg as a string (ignoring terminating NUL bytes)
+	-t code	  0 ==> generate test vectors, 1 ==> test FNV hash
+ 	-v	  verbose mode, print arg after hash (implies -m)
+	arg	  string (if -s was given) or filename (default stdin)
+
+The fnv032, fnv064 implement the historic FNV-0 hash.
+The fnv132, fnv164 implement the recommended FNV-1 hash.
+The fnv1a32, fnv1a64 implement the recommended FNV-1a hash.
+
+This is the original historic FNV algorithm with a 0 offset basis.
+It is recommended that FNV-1, with a non-0 offset basis be used instead.
+
+To test FNV hashes, try:
+
+	fnv032 -t 1 -v
+	fnv132 -t 1 -v
+	fnv1a32 -t 1 -v
+
+	fnv064 -t 1 -v
+	fnv164 -t 1 -v
+	fnv1a64 -t 1 -v
+
+If you are compiling, try:
+
+	make check
+
+
+#==================#
+# FNV hash library #
+#==================#
+
+The libfnv.a library implements both a 32 bit and a 64 bit FNV hash
+on collections of bytes, a NUL terminated strings or on an open file
+descriptor.
+
+Here is the 32 bit FNV 1 hash:
+
+	Fnv32_t fnv_32_buf(void *buf, int len, Fnv32_t hval);	/* byte buf */
+	Fnv32_t fnv_32_str(char *string, Fnv32_t hval);		/* string */
+
+Here is the 32 bit FNV 1a hash:
+
+	Fnv32_t fnv_32a_buf(void *buf, int len, Fnv32_t hval);	/* byte buf */
+	Fnv32_t fnv_32a_str(char *string, Fnv32_t hval);	/* string */
+
+Here is the 64 bit FNV 1 hash:
+
+	Fnv64_t fnv_64_buf(void *buf, int len, Fnv64_t hval);	/* byte buf */
+	Fnv64_t fnv_64_str(char *string, Fnv64_t hval);		/* string */
+
+Here is the 64 bit FNV 1a hash:
+
+	Fnv64_t fnv_64a_buf(void *buf, int len, Fnv64_t hval);	/* byte buf */
+	Fnv64_t fnv_64a_str(char *string, Fnv64_t hval);	/* string */
+
+On the first call to a hash function, one must supply the initial basis
+that is appropriate for the hash in question:
+
+    FNV-0:	(not recommended)
+
+	FNV0_32_INIT		/* 32 bit FNV-0 initial basis */
+	FNV0_64_INIT		/* 64 bit FNV-0 initial basis */
+
+    FNV-1:
+
+	FNV1_32_INIT		/* 32 bit FNV-1 initial basis */
+	FNV1_64_INIT		/* 64 bit FNV-1 initial basis */
+
+    FNV-1a:
+
+	FNV1A_32_INIT		/* 32 bit FNV-1a initial basis */
+	FNV1A_64_INIT		/* 64 bit FNV-1a initial basis */
+
+For example to perform a 64 bit FNV-1 hash:
+
+	#include "fnv.h"
+
+	Fnv64_t hash_val;
+
+	hash_val = fnv_64_str("a string", FNV1_64_INIT);
+	hash_val = fnv_64_str("more string", hash_val);
+
+produces the same final hash value as:
+
+	hash_val = fnv_64_str("a stringmore string", FNV1_64_INIT);
+
+NOTE: If one used 'FNV0_64_INIT' instead of 'FNV1_64_INIT' one would get the
+      historic FNV-0 hash instead recommended FNV-1 hash.
+
+To perform a 32 bit FNV-1 hash:
+
+	#include "fnv.h"
+
+	Fnv32_t hash_val;
+
+	hash_val = fnv_32_buf(buf, length_of_buf, FNV1_32_INIT);
+	hash_val = fnv_32_str("more data", hash_val);
+
+To perform a 64 bit FNV-1a hash:
+
+	#include "fnv.h"
+
+	Fnv64_t hash_val;
+
+	hash_val = fnv_64a_buf(buf, length_of_buf, FNV1_64_INIT);
+	hash_val = fnv_64a_str("more data", hash_val);
+
+=-=
+
+chongo <Landon Curt Noll> /\oo/\
+http://www.isthe.com/chongo
+
+Share and Enjoy!