components/rappor/rappor_parameters.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_RAPPOR_RAPPOR_PARAMETERS_H_
   6 #define COMPONENTS_RAPPOR_RAPPOR_PARAMETERS_H_
   7
   8 #include <string>
   9
  10 namespace rappor {
  11
  12 enum Probability {
  13   PROBABILITY_75,    // 75%
  14   PROBABILITY_50,    // 50%
  15   PROBABILITY_25,    // 25%
  16 };
  17
  18 // An object describing a rappor metric and the parameters used to generate it.
  19 //
  20 // For a full description of the rappor metrics, see
  21 // http://www.chromium.org/developers/design-documents/rappor
  22 struct RapporParameters {
  23   // Get a string representing the parameters, for DCHECK_EQ.
  24   std::string ToString() const;
  25
  26   // The maximum number of cohorts we divide clients into.
  27   static const int kMaxCohorts;
  28
  29   // The number of cohorts to divide the reports for this metric into.
  30   int num_cohorts;
  31
  32   // The number of bytes stored in the Bloom filter.
  33   int bloom_filter_size_bytes;
  34   // The number of hash functions used in the Bloom filter.
  35   int bloom_filter_hash_function_count;
  36
  37   // The probability that a bit will be redacted with fake data.
  38   Probability fake_prob;
  39   // The probability that a fake bit will be a one.
  40   Probability fake_one_prob;
  41
  42   // The probability that a one bit in the redacted data reports as one.
  43   Probability one_coin_prob;
  44   // The probability that a zero bit in the redacted data reports as one.
  45   Probability zero_coin_prob;
  46 };
  47
  48 }  // namespace rappor
  49
  50 #endif  // COMPONENTS_RAPPOR_RAPPOR_PARAMETERS_H_