| // Copyright (c) 2012 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 "base/metrics/bucket_ranges.h" |
| |
| #include <cmath> |
| |
| #include "base/logging.h" |
| #include "base/metrics/crc32.h" |
| |
| namespace base { |
| |
| BucketRanges::BucketRanges(size_t num_ranges) |
| : ranges_(num_ranges, 0), |
| checksum_(0) {} |
| |
| BucketRanges::~BucketRanges() = default; |
| |
| uint32_t BucketRanges::CalculateChecksum() const { |
| // Crc of empty ranges_ happens to be 0. This early exit prevents trying to |
| // take the address of ranges_[0] which will fail for an empty vector even |
| // if that address is never used. |
| const size_t ranges_size = ranges_.size(); |
| if (ranges_size == 0) |
| return 0; |
| |
| // Checksum is seeded with the ranges "size". |
| return Crc32(static_cast<uint32_t>(ranges_size), &ranges_[0], |
| sizeof(ranges_[0]) * ranges_size); |
| } |
| |
| bool BucketRanges::HasValidChecksum() const { |
| return CalculateChecksum() == checksum_; |
| } |
| |
| void BucketRanges::ResetChecksum() { |
| checksum_ = CalculateChecksum(); |
| } |
| |
| bool BucketRanges::Equals(const BucketRanges* other) const { |
| if (checksum_ != other->checksum_) |
| return false; |
| if (ranges_.size() != other->ranges_.size()) |
| return false; |
| for (size_t index = 0; index < ranges_.size(); ++index) { |
| if (ranges_[index] != other->ranges_[index]) |
| return false; |
| } |
| return true; |
| } |
| |
| } // namespace base |