PearsonHash has been added to libbu++, I...have no way of really verifying that

our results are right, but I can at least write a unit test and make sure that
minor changes in the inputs create different results in the output.

1 files changed, 41 insertions, 0 deletions

diff --git a/src/pearsonhash.h b/src/pearsonhash.h
new file mode 100644
index 0000000..af8dfc3
--- /dev/null
+++ b/src/pearsonhash.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2007-2011 Xagasoft, All rights reserved.
+ *
+ * This file is part of the libbu++ library and is released under the
+ * terms of the license contained in the file LICENSE.
+ */
+
+#ifndef BU_PEARSON_HASH_H
+#define BU_PEARSON_HASH_H
+
+#include "bu/cryptohash.h"
+
+namespace Bu
+{
+        /**
+         * A pearson hash is a non-cryptographically secure hashing function that
+         * is very light on resources, very fast, and produces a single byte
+         * as it's output.  It is strongly dependant on every byte in the input,
+         * which means that it's a good choice for adding to short messages to
+         * ensure that the contents of the messages are unchanged.
+         */
+        class PearsonHash : public Bu::CryptoHash
+        {
+        public:
+                PearsonHash();
+                virtual ~PearsonHash();
+
+                virtual void reset();
+                virtual void setSalt( const Bu::String &sSalt );
+                virtual void addData( const void *sData, int iSize );
+                using Bu::CryptoHash::addData;
+                virtual String getResult();
+                virtual void writeResult( Stream &sOut );
+
+        private:
+                static uint8_t aSBox[256];
+                uint8_t iValue;
+        };
+};
+
+#endif