From c63bee1078c6b8370aadaa73f0bb5f2333fd78cf Mon Sep 17 00:00:00 2001
From: Vsevolod Stakhov <vsevolod@highsecure.ru>
Date: Wed, 17 Dec 2014 17:10:21 +0000
Subject: Add comparision function for shingles.

---
 src/libutil/shingles.c | 15 +++++++++++++++
 src/libutil/shingles.h | 10 ++++++++++
 2 files changed, 25 insertions(+)

diff --git a/src/libutil/shingles.c b/src/libutil/shingles.c
index 2307a318c..653fa5356 100644
--- a/src/libutil/shingles.c
+++ b/src/libutil/shingles.c
@@ -135,3 +135,18 @@ rspamd_shingles_default_filter (guint64 *input, gsize count,
 
 	return minimal;
 }
+
+
+gdouble rspamd_shingles_compare (const struct rspamd_shingle *a,
+		const struct rspamd_shingle *b)
+{
+	gint i, common = 0;
+
+	for (i = 0; i < RSPAMD_SHINGLE_SIZE; i ++) {
+		if (a->hashes[i] == b->hashes[i]) {
+			common ++;
+		}
+	}
+
+	return (gdouble)common / 84.0;
+}
diff --git a/src/libutil/shingles.h b/src/libutil/shingles.h
index 571199992..39e9cf38d 100644
--- a/src/libutil/shingles.h
+++ b/src/libutil/shingles.h
@@ -57,6 +57,16 @@ struct rspamd_shingle* rspamd_shingles_generate (GArray *input,
 		rspamd_shingles_filter filter,
 		gpointer filterd);
 
+/**
+ * Compares two shingles and return result as a floating point value - 1.0
+ * for completely similar shingles and 0.0 for completely different ones
+ * @param a
+ * @param b
+ * @return
+ */
+gdouble rspamd_shingles_compare (const struct rspamd_shingle *a,
+		const struct rspamd_shingle *b);
+
 /**
  * Default filtering function
  */
-- 
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