RAPPOR implementation

components/rappor/bloom_filter.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_RAPPOR_BLOOM_FILTER_H_
+#define COMPONENTS_RAPPOR_BLOOM_FILTER_H_
+
+#include <stdint.h>
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "components/rappor/byte_vector_utils.h"
+
+namespace rappor {
+
+// BloomFilter is a simple bloom filter for keeping track of a set of strings.

[Ilya Sherman, 2014/01/10 11:00:32]

nit: "bloom filter" -> "Bloom filter", since "Bloom" is a last name (applies
throughout)

[Steven Holte, 2014/01/14 00:47:54]

Done.

+class BloomFilter {

[Ilya Sherman, 2014/01/10 11:00:32]

Hmm, I'm going to be we already have a Bloom filter class in the Chromium
codebase, e.g. for safebrowsing.  Is this class really different enough to be
needed?

[Steven Holte, 2014/01/14 00:47:54]

Yes.  Extracting safebrowsing's bloom filter looks very non-trivial.

+ public:
+  BloomFilter(uint32_t bytes_size, uint32_t hash_count);

[Ilya Sherman, 2014/01/10 11:00:32]

nit: Please document the parameters, including the restriction that hash_count
must be <= 4.

[Steven Holte, 2014/01/14 00:47:54]

Done.

+  ~BloomFilter();
+
+  void AddString(const std::string& str);
+  void AddStrings(const std::vector<std::string>& strings);

[Ilya Sherman, 2014/01/10 11:00:32]

nit: Please document these methods (fine to be very brief, which is a nice way
to quickly indicate that the methods don't do anything surprising).

[Steven Holte, 2014/01/14 00:47:54]

Done.

+
+  // Returns the current value of the bloom filter's bit array.
+  const ByteVector& bytes() const { return bytes_; };
+  // Returns the number of bits set for each string added to the filter.
+  uint32_t hash_count() const { return hash_count_; };
+
+ private:
+  // Stores the bit array of the bloom filter.

[Ilya Sherman, 2014/01/10 11:00:32]

Optional nit: "bit array" -> "byte array"?

[Steven Holte, 2014/01/14 00:47:54]

Done.

+  ByteVector bytes_;
+  // The number of bits to set for each string added.
+  uint32_t hash_count_;

[Ilya Sherman, 2014/01/10 11:00:32]

nit: This might be more clear if named something like "hash_function_count_".

[Steven Holte, 2014/01/14 00:47:54]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(BloomFilter);
+};
+
+}  // namespace rappor
+
+#endif  // COMPONENTS_RAPPOR_BLOOM_FILTER_H_