Remove abseil dependency from HexEncode method

Currently the HexEncode method defined in util/stringprintf.h depends on
absl::Span, which is part of abseil. This patch removes the dependency,
allowing the method to be more widely used.
Bug: b/158660166
Change-Id: I37715271391000b5c61d5a657f604db2bc6c882e
Reviewed-on: https://chromium-review.googlesource.com/c/openscreen/+/3001949
Reviewed-by: Jordan Bayles <jophba@chromium.org>
Commit-Queue: Jordan Bayles <jophba@chromium.org>

7 files changed, 16 insertions, 13 deletions

diff --git a/cast/standalone_receiver/cast_service.cc b/cast/standalone_receiver/cast_service.cc
index 009190b0..0e3d9c9c 100644
--- a/cast/standalone_receiver/cast_service.cc
+++ b/cast/standalone_receiver/cast_service.cc
@@ -69,7 +69,8 @@ CastService::CastService(CastService::Configuration config)
   if (discovery_publisher_) {
     ReceiverInfo info;
     info.port = local_endpoint_.port;
-    info.unique_id = HexEncode(config.interface.hardware_address);
+    info.unique_id = HexEncode(config.interface.hardware_address.data(),
+                               config.interface.hardware_address.size());
     info.friendly_name = config.friendly_name;
     info.model_name = config.model_name;
     info.capabilities = kHasVideoOutput | kHasAudioOutput;
diff --git a/cast/streaming/offer_messages.cc b/cast/streaming/offer_messages.cc
index 3e816026..eeefcc5d 100644
--- a/cast/streaming/offer_messages.cc
+++ b/cast/streaming/offer_messages.cc
@@ -202,8 +202,8 @@ Json::Value Stream::ToJson() const {
                 "this code assumes Ssrc fits in a Json::UInt");
   root["ssrc"] = static_cast<Json::UInt>(ssrc);
   root["targetDelay"] = static_cast<int>(target_delay.count());
-  root["aesKey"] = HexEncode(aes_key);
-  root["aesIvMask"] = HexEncode(aes_iv_mask);
+  root["aesKey"] = HexEncode(aes_key.data(), aes_key.size());
+  root["aesIvMask"] = HexEncode(aes_iv_mask.data(), aes_iv_mask.size());
   root["receiverRtcpEventLog"] = receiver_rtcp_event_log;
   root["receiverRtcpDscp"] = receiver_rtcp_dscp;
   root["timeBase"] = "1/" + std::to_string(rtp_timebase);
diff --git a/cast/streaming/receiver_packet_router.cc b/cast/streaming/receiver_packet_router.cc
index 1ac4266a..23b99ce4 100644
--- a/cast/streaming/receiver_packet_router.cc
+++ b/cast/streaming/receiver_packet_router.cc
@@ -73,10 +73,11 @@ void ReceiverPacketRouter::OnReceivedPacket(const IPEndpoint& source,
       InspectPacketForRouting(packet);
   if (seems_like.first == ApparentPacketType::UNKNOWN) {
     constexpr int kMaxPartiaHexDumpSize = 96;
+    const std::size_t encode_size =
+        std::min(packet.size(), static_cast<size_t>(kMaxPartiaHexDumpSize));
     OSP_LOG_WARN << "UNKNOWN packet of " << packet.size()
                  << " bytes. Partial hex dump: "
-                 << HexEncode(absl::Span<const uint8_t>(packet).subspan(
-                        0, kMaxPartiaHexDumpSize));
+                 << HexEncode(packet.data(), encode_size);
     return;
   }
   auto it = receivers_.find(seems_like.second);
diff --git a/cast/streaming/sender_packet_router.cc b/cast/streaming/sender_packet_router.cc
index c2b23dbf..684b1fb2 100644
--- a/cast/streaming/sender_packet_router.cc
+++ b/cast/streaming/sender_packet_router.cc
@@ -102,10 +102,11 @@ void SenderPacketRouter::OnReceivedPacket(const IPEndpoint& source,
       InspectPacketForRouting(packet);
   if (seems_like.first != ApparentPacketType::RTCP) {
     constexpr int kMaxPartiaHexDumpSize = 96;
+    const std::size_t encode_size =
+        std::min(packet.size(), static_cast<size_t>(kMaxPartiaHexDumpSize));
     OSP_LOG_WARN << "UNKNOWN packet of " << packet.size()
                  << " bytes. Partial hex dump: "
-                 << HexEncode(absl::Span<const uint8_t>(packet).subspan(
-                        0, kMaxPartiaHexDumpSize));
+                 << HexEncode(packet.data(), encode_size);
     return;
   }
   const auto it = FindEntry(seems_like.second);
diff --git a/util/stringprintf.cc b/util/stringprintf.cc
index 2d9bba22..49c29dc8 100644
--- a/util/stringprintf.cc
+++ b/util/stringprintf.cc
@@ -32,11 +32,11 @@ std::string StringPrintf(const char* format, ...) {
   return result;
 }
 
-std::string HexEncode(absl::Span<const uint8_t> bytes) {
+std::string HexEncode(const uint8_t* bytes, std::size_t len) {
   std::ostringstream hex_dump;
   hex_dump << std::setfill('0') << std::hex;
-  for (const uint8_t byte : bytes) {
-    hex_dump << std::setw(2) << static_cast<int>(byte);
+  for (std::size_t i = 0; i < len; i++) {
+    hex_dump << std::setw(2) << static_cast<int>(bytes[i]);
   }
   return hex_dump.str();
 }
diff --git a/util/stringprintf.h b/util/stringprintf.h
index 0e7984e1..7e54be3c 100644
--- a/util/stringprintf.h
+++ b/util/stringprintf.h
@@ -55,7 +55,7 @@ void PrettyPrintAsciiHex(std::ostream& os, It first, It last) {
 }
 
 // Returns a hex string representation of the given |bytes|.
-std::string HexEncode(absl::Span<const uint8_t> bytes);
+std::string HexEncode(const uint8_t* bytes, std::size_t len);
 
 }  // namespace openscreen
 
diff --git a/util/stringprintf_unittest.cc b/util/stringprintf_unittest.cc
index e37e7cb6..bf882163 100644
--- a/util/stringprintf_unittest.cc
+++ b/util/stringprintf_unittest.cc
@@ -20,13 +20,13 @@ TEST(StringPrintf, ProducesFormattedStrings) {
 
 TEST(HexEncode, ProducesEmptyStringFromEmptyByteArray) {
   const uint8_t kSomeMemoryLocation = 0;
-  EXPECT_EQ("", HexEncode(absl::Span<const uint8_t>(&kSomeMemoryLocation, 0)));
+  EXPECT_EQ("", HexEncode(&kSomeMemoryLocation, 0));
 }
 
 TEST(HexEncode, ProducesHexStringsFromBytes) {
   const uint8_t kMessage[] = "Hello world!";
   const char kMessageInHex[] = "48656c6c6f20776f726c642100";
-  EXPECT_EQ(kMessageInHex, HexEncode(kMessage));
+  EXPECT_EQ(kMessageInHex, HexEncode(kMessage, sizeof(kMessage)));
 }
 
 }  // namespace