// 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 #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(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