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#include "components/metrics/metrics_hashes.h"
6
7#include "base/logging.h"
8#include "base/md5.h"
9#include "base/sys_byteorder.h"
10
11namespace metrics {
12
13namespace {
14
15// Converts the 8-byte prefix of an MD5 hash into a uint64 value.
16inline uint64 HashToUInt64(const std::string& hash) {
17  uint64 value;
18  DCHECK_GE(hash.size(), sizeof(value));
19  memcpy(&value, hash.data(), sizeof(value));
20  return base::HostToNet64(value);
21}
22
23}  // namespace
24
25uint64 HashMetricName(const std::string& name) {
26  // Create an MD5 hash of the given |name|, represented as a byte buffer
27  // encoded as an std::string.
28  base::MD5Context context;
29  base::MD5Init(&context);
30  base::MD5Update(&context, name);
31
32  base::MD5Digest digest;
33  base::MD5Final(&digest, &context);
34
35  std::string hash_str(reinterpret_cast<char*>(digest.a), arraysize(digest.a));
36  return HashToUInt64(hash_str);
37}
38
39}  // namespace metrics
40