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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/metrics/metrics_hashes.h"
#include <string.h>
#include <array>
#include <string_view>
#include "base/check_op.h"
#include "base/containers/span.h"
#include "base/numerics/byte_conversions.h"
#include "third_party/boringssl/src/include/openssl/md5.h"
#include "third_party/boringssl/src/include/openssl/sha.h"
namespace base {
uint64_t HashMetricName(std::string_view name) {
// Corresponding Python code for quick look up:
//
// import struct
// import hashlib
// struct.unpack('>Q', hashlib.md5(name.encode('utf-8')).digest()[:8])[0]
//
std::array<uint8_t, MD5_DIGEST_LENGTH> hash;
::MD5(reinterpret_cast<const uint8_t*>(name.data()), name.size(),
hash.data());
return U64FromBigEndian(base::span(hash).first<8>());
}
uint32_t HashMetricNameAs32Bits(std::string_view name) {
std::array<uint8_t, MD5_DIGEST_LENGTH> hash;
::MD5(reinterpret_cast<const uint8_t*>(name.data()), name.size(),
hash.data());
return U32FromBigEndian(base::span(hash).first<4>());
}
uint32_t ParseMetricHashTo32Bits(uint64_t hash) {
return (hash >> 32);
}
uint32_t HashFieldTrialName(std::string_view name) {
// SHA-1 is designed to produce a uniformly random spread in its output space,
// even for nearly-identical inputs.
std::array<uint8_t, SHA_DIGEST_LENGTH> hash;
::SHA1(reinterpret_cast<const uint8_t*>(name.data()), name.size(),
hash.data());
return U32FromLittleEndian(base::span(hash).first<4>());
}
} // namespace base
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