Roll forward to cl/338482889

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: Ic2bdb234e89f3c5860d1b483dd4bce689f13d057

cpp/platform/base/bluetooth_utils.cc

@@ -0,0 +1,75 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "platform/base/bluetooth_utils.h"
+
+#include "absl/strings/escaping.h"
+#include "absl/strings/str_format.h"
+
+namespace location {
+namespace nearby {
+
+std::string BluetoothUtils::ToString(const ByteArray& bluetooth_mac_address) {
+  std::string colon_delimited_string;
+
+  if (bluetooth_mac_address.size() != kBluetoothMacAddressLength)
+    return colon_delimited_string;
+
+  if (IsBluetoothMacAddressUnset(bluetooth_mac_address))
+    return colon_delimited_string;
+
+  for (auto byte : std::string(bluetooth_mac_address)) {
+    if (!colon_delimited_string.empty())
+      absl::StrAppend(&colon_delimited_string, ":");
+    absl::StrAppend(&colon_delimited_string, absl::StrFormat("%02X", byte));
+  }
+  return colon_delimited_string;
+}
+
+ByteArray BluetoothUtils::FromString(absl::string_view bluetooth_mac_address) {
+  std::string bt_mac_address(bluetooth_mac_address);
+
+  // Remove the colon delimiters.
+  bt_mac_address.erase(
+      std::remove(bt_mac_address.begin(), bt_mac_address.end(), ':'),
+      bt_mac_address.end());
+
+  // If the bluetooth mac address is invalid (wrong size), return a null byte
+  // array.
+  if (bt_mac_address.length() != kBluetoothMacAddressLength * 2) {
+    return ByteArray();
+  }
+
+  // Convert to bytes. If MAC Address bytes are unset, return a null byte array.
+  auto bt_mac_address_string(absl::HexStringToBytes(bt_mac_address));
+  auto bt_mac_address_bytes =
+      ByteArray(bt_mac_address_string.data(), bt_mac_address_string.size());
+  if (IsBluetoothMacAddressUnset(bt_mac_address_bytes)) {
+    return ByteArray();
+  }
+  return bt_mac_address_bytes;
+}
+
+bool BluetoothUtils::IsBluetoothMacAddressUnset(
+    const ByteArray& bluetooth_mac_address_bytes) {
+  for (int i = 0; i < bluetooth_mac_address_bytes.size(); i++) {
+    if (bluetooth_mac_address_bytes.data()[i] != 0) {
+      return false;
+    }
+  }
+  return true;
+}
+
+}  // namespace nearby
+}  // namespace location