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// 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/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
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