From 38a5bee71f6b49515cd105a9467ff602ff9dee64 Mon Sep 17 00:00:00 2001
From: Chris Dyer <cdyer@cs.cmu.edu>
Date: Tue, 13 Sep 2011 13:25:46 +0100
Subject: optional support for doing perfect hashing of feature strings to save
 lots of memory

---
 utils/perfect_hash.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 utils/perfect_hash.h

(limited to 'utils/perfect_hash.h')

diff --git a/utils/perfect_hash.h b/utils/perfect_hash.h
new file mode 100644
index 00000000..8ac11f18
--- /dev/null
+++ b/utils/perfect_hash.h
@@ -0,0 +1,24 @@
+#ifndef _PERFECT_HASH_MAP_H_
+#define _PERFECT_HASH_MAP_H_
+
+#include "config.h"
+
+#ifndef HAVE_CMPH
+#error libcmph is required to use PerfectHashFunction
+#endif
+
+#include <vector>
+#include <boost/utility.hpp>
+#include "cmph.h"
+
+class PerfectHashFunction : boost::noncopyable {
+ public:
+  explicit PerfectHashFunction(const std::string& fname);
+  ~PerfectHashFunction();
+  size_t operator()(const std::string& key) const;
+  size_t number_of_keys() const;
+ private:
+  cmph_t *mphf_;
+};
+
+#endif
-- 
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