| // Copyright 2014 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. |
| |
| #include "components/rappor/bloom_filter.h" |
| |
| #include "base/logging.h" |
| #include "third_party/smhasher/src/City.h" |
| |
| namespace rappor { |
| |
| BloomFilter::BloomFilter(uint32_t bytes_size, |
| uint32_t hash_function_count, |
| uint32_t hash_seed_offset) |
| : bytes_(bytes_size), |
| hash_function_count_(hash_function_count), |
| hash_seed_offset_(hash_seed_offset) { |
| DCHECK_GT(bytes_size, 0u); |
| } |
| |
| BloomFilter::~BloomFilter() {} |
| |
| void BloomFilter::AddString(const std::string& str) { |
| for (size_t i = 0; i < hash_function_count_; ++i) { |
| // Using CityHash here because we have support for it in Dremel. Many hash |
| // functions, such as MD5, SHA1, or Murmur, would probably also work. |
| uint32_t index = |
| CityHash64WithSeed(str.data(), str.size(), hash_seed_offset_ + i); |
| // Note that the "bytes" are uint8_t, so they are always 8-bits. |
| uint32_t byte_index = (index / 8) % bytes_.size(); |
| uint32_t bit_index = index % 8; |
| bytes_[byte_index] |= 1 << bit_index; |
| } |
| } |
| |
| } // namespace rappor |