1 files changed, 101 insertions, 0 deletions
diff --git a/src/libutil/shingles.h b/src/libutil/shingles.h
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+/*-
+ * Copyright 2016 Vsevolod Stakhov
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef SHINGLES_H_
+#define SHINGLES_H_
+
+#include "config.h"
+#include "mem_pool.h"
+
+#define RSPAMD_SHINGLE_SIZE 32
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct rspamd_shingle {
+	guint64 hashes[RSPAMD_SHINGLE_SIZE];
+};
+
+enum rspamd_shingle_alg {
+	RSPAMD_SHINGLES_OLD = 0,
+	RSPAMD_SHINGLES_XXHASH,
+	RSPAMD_SHINGLES_MUMHASH,
+	RSPAMD_SHINGLES_FAST
+};
+
+/**
+ * Shingles filtering function
+ * @param input input array of hashes
+ * @param count number of hashes in the vector
+ * @return shingle value
+ */
+typedef guint64 (*rspamd_shingles_filter)(guint64 *input, gsize count,
+										  gint shno, const guchar *key, gpointer ud);
+
+/**
+ * Generate shingles from the input of fixed size strings using lemmatizer
+ * if needed
+ * @param input array of `rspamd_fstring_t`
+ * @param key secret key used to generate shingles
+ * @param pool pool to allocate shingles array
+ * @param filter hashes filtering function
+ * @param filterd opaque data for filtering function
+ * @return shingles array
+ */
+struct rspamd_shingle *rspamd_shingles_from_text(GArray *input,
+												 const guchar key[16],
+												 rspamd_mempool_t *pool,
+												 rspamd_shingles_filter filter,
+												 gpointer filterd,
+												 enum rspamd_shingle_alg alg);
+
+/**
+ * Generate shingles from the DCT matrix of an image
+ * @param dct discrete cosine transfor matrix (must be 64x64)
+ * @param key secret key used to generate shingles
+ * @param pool pool to allocate shingles array
+ * @param filter hashes filtering function
+ * @param filterd opaque data for filtering function
+ * @return shingles array
+ */
+struct rspamd_shingle *rspamd_shingles_from_image(guchar *dct,
+												  const guchar key[16],
+												  rspamd_mempool_t *pool,
+												  rspamd_shingles_filter filter,
+												  gpointer filterd,
+												  enum rspamd_shingle_alg alg);
+
+/**
+ * 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
+ */
+guint64 rspamd_shingles_default_filter(guint64 *input, gsize count,
+									   gint shno, const guchar *key, gpointer ud);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SHINGLES_H_ */