read endpoint info

PiperOrigin-RevId: 729312008

Package.swift

@@ -457,6 +457,7 @@ let package = Package(
         "connections/implementation/analytics/throughput_recorder_test.cc",
         "connections/implementation/mediums/advertisements/data_element_test.cc",
         "connections/implementation/mediums/advertisements/dct_advertisement_test.cc",
+        "connections/implementation/mediums/advertisements/advertisement_util_test.cc",
         "connections/implementation/mediums/ble_v2_test.cc",
         "connections/implementation/mediums/ble_v2/bloom_filter_test.cc",
         "connections/implementation/mediums/ble_v2/ble_packet_test.cc",

connections/implementation/mediums/advertisements/BUILD

@@ -41,6 +41,18 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "util",
+    srcs = ["advertisement_util.cc"],
+    hdrs = ["advertisement_util.h"],
+    deps = [
+        ":dct_advertisement",
+        "//internal/platform:base",
+        "//internal/platform:logging",
+        "//internal/platform:util",
+    ],
+)
+
 cc_test(
     name = "data_element_test",
     srcs = ["data_element_test.cc"],
@@ -64,3 +76,15 @@ cc_test(
         "@com_google_googletest//:gtest_main",
     ],
 )
+
+cc_test(
+    name = "advertisement_util_test",
+    srcs = ["advertisement_util_test.cc"],
+    deps = [
+        ":util",
+        "//internal/platform:base",
+        "//internal/platform:util",
+        "@com_github_protobuf_matchers//protobuf-matchers",
+        "@com_google_googletest//:gtest_main",
+    ],
+)

connections/implementation/mediums/advertisements/advertisement_util.cc

@@ -0,0 +1,60 @@
+// Copyright 2025 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 "connections/implementation/mediums/advertisements/advertisement_util.h"
+
+#include <cstdint>
+#include <optional>
+#include <string>
+
+#include "internal/platform/byte_array.h"
+#include "internal/platform/stream_reader.h"
+
+namespace nearby::connections::advertisements {
+
+std::optional<std::string> ReadDeviceName(const ByteArray& endpoint_info) {
+  StreamReader reader(endpoint_info);
+  std::optional<uint8_t> version = reader.ReadBits(3);
+  if (!version.has_value() || *version != 1) {
+    return std::nullopt;
+  }
+
+  std::optional<uint8_t> has_device_name = reader.ReadBits(1);
+  if (!has_device_name.has_value() || *has_device_name == 0) {
+    return std::nullopt;
+  }
+
+  std::optional<uint8_t> device_type = reader.ReadBits(4);
+  if (!device_type.has_value()) {
+    return std::nullopt;
+  }
+
+  if (!reader.ReadBytes(16).has_value()) {
+    return std::nullopt;
+  }
+
+  std::optional<uint8_t> device_length = reader.ReadUint8();
+  if (!device_length.has_value() || *device_length == 0) {
+    return std::nullopt;
+  }
+
+  std::optional<ByteArray> device_name = reader.ReadBytes(*device_length);
+  if (!device_name.has_value()) {
+    return std::nullopt;
+  }
+
+  return std::string(*device_name);
+}
+
+}  // namespace nearby::connections::advertisements

connections/implementation/mediums/advertisements/advertisement_util.h

@@ -0,0 +1,30 @@
+// Copyright 2025 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.
+
+#ifndef THIRD_PARTY_NEARBY_CONNECTIONS_IMPLEMENTATION_MEDIUMS_ADVERTISEMENTS_ADVERTISEMENT_UTIL_H_
+#define THIRD_PARTY_NEARBY_CONNECTIONS_IMPLEMENTATION_MEDIUMS_ADVERTISEMENTS_ADVERTISEMENT_UTIL_H_
+
+#include <optional>
+#include <string>
+
+#include "internal/platform/byte_array.h"
+
+namespace nearby::connections::advertisements {
+
+// Reads the device name from the endpoint info.
+std::optional<std::string> ReadDeviceName(const ByteArray& endpoint_info);
+
+}  // namespace nearby::connections::advertisements
+
+#endif  // THIRD_PARTY_NEARBY_CONNECTIONS_IMPLEMENTATION_MEDIUMS_ADVERTISEMENTS_ADVERTISEMENT_UTIL_H_

connections/implementation/mediums/advertisements/advertisement_util_test.cc

@@ -0,0 +1,53 @@
+// Copyright 2025 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 "connections/implementation/mediums/advertisements/advertisement_util.h"
+
+#include <optional>
+#include <string>
+
+#include "gtest/gtest.h"
+#include "internal/platform/byte_array.h"
+
+namespace nearby::connections::advertisements {
+namespace {
+
+TEST(AdvertisementUtilTest, ReadDeviceName) {
+  ByteArray endpoint_info{
+      "\x32\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0b"
+      "\x54\x65\x73\x74\x20\x64\x65\x76\x69\x63\x65",
+      29};
+  std::optional<std::string> parsed_device_name = ReadDeviceName(endpoint_info);
+  ASSERT_TRUE(parsed_device_name.has_value());
+  EXPECT_EQ(*parsed_device_name, "Test device");
+}
+
+TEST(AdvertisementUtilTest, ReadInvaidDeviceName) {
+  EXPECT_FALSE(ReadDeviceName(ByteArray("")).has_value());
+  EXPECT_FALSE(ReadDeviceName(ByteArray("\x30")).has_value());
+  EXPECT_FALSE(ReadDeviceName(ByteArray("\x32")).has_value());
+  EXPECT_FALSE(
+      ReadDeviceName(ByteArray("\x32\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+                               "\x00\x00\x00\x00\x00\x00",
+                               17))
+          .has_value());
+  EXPECT_FALSE(
+      ReadDeviceName(ByteArray("\x32\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+                               "\x00\x00\x00\x00\x00\x00\x0b"
+                               "\x54\x65\x73\x74\x20\x64\x65\x76\x69\x63\x65",
+                               25))
+          .has_value());
+}
+
+}  // namespace
+}  // namespace nearby::connections::advertisements

internal/platform/stream_reader.h

@@ -27,7 +27,7 @@ namespace nearby {
 // A base {@link InputStream } for reading the contents of a byte array.
 class StreamReader {
  public:
-  explicit StreamReader(ByteArray &buffer) : buffer_{buffer} {}
+  explicit StreamReader(const ByteArray &buffer) : buffer_{buffer} {}
   StreamReader(const StreamReader &) = delete;
   StreamReader &operator=(const StreamReader &) = delete;
   ~StreamReader() = default;
@@ -54,7 +54,7 @@ class StreamReader {
 
   uint8_t bits_unused_{0};
   uint8_t bits_buffer_{0};
-  ByteArray &buffer_;
+  const ByteArray &buffer_;
   size_t position_{0};
 };