1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "uploader/metrics_hashes.h" 18 19 #include "base/logging.h" 20 #include "base/md5.h" 21 #include "base/sys_byteorder.h" 22 23 namespace metrics { 24 25 namespace { 26 27 // Converts the 8-byte prefix of an MD5 hash into a uint64 value. 28 inline uint64_t HashToUInt64(const std::string& hash) { 29 uint64_t value; 30 DCHECK_GE(hash.size(), sizeof(value)); 31 memcpy(&value, hash.data(), sizeof(value)); 32 return base::HostToNet64(value); 33 } 34 35 } // namespace 36 37 uint64_t HashMetricName(const std::string& name) { 38 // Create an MD5 hash of the given |name|, represented as a byte buffer 39 // encoded as an std::string. 40 base::MD5Context context; 41 base::MD5Init(&context); 42 base::MD5Update(&context, name); 43 44 base::MD5Digest digest; 45 base::MD5Final(&digest, &context); 46 47 std::string hash_str(reinterpret_cast<char*>(digest.a), arraysize(digest.a)); 48 return HashToUInt64(hash_str); 49 } 50 51 } // namespace metrics 52
