1 files changed, 63 insertions, 0 deletions

diff --git a/bloom.h b/bloom.h
index d0fcc5f0aa..b9ce422ca2 100644
--- a/bloom.h
+++ b/bloom.h
@@ -1,6 +1,60 @@
 #ifndef BLOOM_H
 #define BLOOM_H
 
+struct bloom_filter_settings {
+	/*
+	 * The version of the hashing technique being used.
+	 * We currently only support version = 1 which is
+	 * the seeded murmur3 hashing technique implemented
+	 * in bloom.c.
+	 */
+	uint32_t hash_version;
+
+	/*
+	 * The number of times a path is hashed, i.e. the
+	 * number of bit positions tht cumulatively
+	 * determine whether a path is present in the
+	 * Bloom filter.
+	 */
+	uint32_t num_hashes;
+
+	/*
+	 * The minimum number of bits per entry in the Bloom
+	 * filter. If the filter contains 'n' entries, then
+	 * filter size is the minimum number of 8-bit words
+	 * that contain n*b bits.
+	 */
+	uint32_t bits_per_entry;
+};
+
+#define DEFAULT_BLOOM_FILTER_SETTINGS { 1, 7, 10 }
+#define BITS_PER_WORD 8
+
+/*
+ * A bloom_filter struct represents a data segment to
+ * use when testing hash values. The 'len' member
+ * dictates how many entries are stored in
+ * 'data'.
+ */
+struct bloom_filter {
+	unsigned char *data;
+	size_t len;
+};
+
+/*
+ * A bloom_key represents the k hash values for a
+ * given string. These can be precomputed and
+ * stored in a bloom_key for re-use when testing
+ * against a bloom_filter. The number of hashes is
+ * given by the Bloom filter settings and is the same
+ * for all Bloom filters and keys interacting with
+ * the loaded version of the commit graph file and
+ * the Bloom data chunks.
+ */
+struct bloom_key {
+	uint32_t *hashes;
+};
+
 /*
  * Calculate the murmur3 32-bit hash value for the given data
  * using the given seed.
@@ -10,4 +64,13 @@
  */
 uint32_t murmur3_seeded(uint32_t seed, const char *data, size_t len);
 
+void fill_bloom_key(const char *data,
+		    size_t len,
+		    struct bloom_key *key,
+		    const struct bloom_filter_settings *settings);
+
+void add_key_to_filter(const struct bloom_key *key,
+					   struct bloom_filter *filter,
+					   const struct bloom_filter_settings *settings);
+
 #endif
\ No newline at end of file