1 files changed, 64 insertions, 0 deletions
diff --git a/chromium/components/federated_learning/floc_id.cc b/chromium/components/federated_learning/floc_id.cc
new file mode 100644
index 00000000000..38caf081581
--- /dev/null
+++ b/chromium/components/federated_learning/floc_id.cc
@@ -0,0 +1,64 @@
+// Copyright 2020 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 "components/federated_learning/floc_id.h"
+
+#include "base/strings/strcat.h"
+#include "base/strings/string_number_conversions.h"
+#include "components/federated_learning/sim_hash.h"
+
+namespace federated_learning {
+
+namespace {
+
+constexpr char kFlocVersion[] = "1.0.0";
+
+// This is only for experimentation and won't be served to websites.
+constexpr size_t kNumberOfBitsInFloc = 50;
+static_assert(kNumberOfBitsInFloc > 0 &&
+                  kNumberOfBitsInFloc <= std::numeric_limits<uint64_t>::digits,
+              "Number of bits in the floc id must be greater than 0 and no "
+              "greater than 64.");
+
+}  // namespace
+
+// static
+FlocId FlocId::CreateFromHistory(
+    const std::unordered_set<std::string>& domains) {
+  return FlocId(SimHashStrings(domains, kNumberOfBitsInFloc));
+}
+
+FlocId::FlocId() = default;
+
+FlocId::FlocId(uint64_t id) : id_(id) {}
+
+FlocId::FlocId(const FlocId& id) = default;
+
+FlocId::~FlocId() = default;
+
+FlocId& FlocId::operator=(const FlocId& id) = default;
+
+FlocId& FlocId::operator=(FlocId&& id) = default;
+
+bool FlocId::IsValid() const {
+  return id_.has_value();
+}
+
+uint64_t FlocId::ToUint64() const {
+  DCHECK(id_.has_value());
+  return id_.value();
+}
+
+std::string FlocId::ToDebugHeaderValue() const {
+  if (!id_.has_value())
+    return "null";
+  return ToHeaderValue();
+}
+
+std::string FlocId::ToHeaderValue() const {
+  DCHECK(id_.has_value());
+  return base::StrCat({base::NumberToString(id_.value()), ".", kFlocVersion});
+}
+
+}  // namespace federated_learning