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// Copyright 2021 The Pigweed Authors
//
// 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 "pw_bluetooth_hci/uart_transport.h"
namespace pw::bluetooth_hci {
StatusWithSize DecodeHciUartData(ConstByteSpan data,
const DecodedPacketCallback& packet_callback) {
size_t bytes_consumed = 0;
while (data.size_bytes() > 0) {
const std::byte packet_indicator = data[0];
data = data.subspan(1); // Pop off the packet indicator byte.
// Note that we do not yet claim the byte consumed until we know what it is,
// as it may be a partial HCI packet which cannot be consumed until later.
size_t packet_size_bytes = 0;
switch (packet_indicator) {
case kUartCommandPacketIndicator: {
const std::optional<CommandPacket> maybe_packet =
CommandPacket::Decode(data, endian::little);
if (!maybe_packet.has_value()) {
return StatusWithSize(
bytes_consumed); // Not enough data to complete this packet.
}
const CommandPacket& packet = maybe_packet.value();
packet_callback(packet);
packet_size_bytes = packet.size_bytes();
break;
}
case kUartAsyncDataPacketIndicator: {
const std::optional<AsyncDataPacket> maybe_packet =
AsyncDataPacket::Decode(data, endian::little);
if (!maybe_packet.has_value()) {
return StatusWithSize(
bytes_consumed); // Not enough data to complete this packet.
}
const AsyncDataPacket& packet = maybe_packet.value();
packet_callback(packet);
packet_size_bytes = packet.size_bytes();
break;
}
case kUartSyncDataPacketIndicator: {
const std::optional<SyncDataPacket> maybe_packet =
SyncDataPacket::Decode(data, endian::little);
if (!maybe_packet.has_value()) {
return StatusWithSize(
bytes_consumed); // Not enough data to complete this packet.
}
const SyncDataPacket& packet = maybe_packet.value();
packet_callback(packet);
packet_size_bytes = packet.size_bytes();
break;
}
case kUartEventPacketIndicator: {
const std::optional<EventPacket> maybe_packet =
EventPacket::Decode(data);
if (!maybe_packet.has_value()) {
return StatusWithSize(
bytes_consumed); // Not enough data to complete this packet.
}
const EventPacket& packet = maybe_packet.value();
packet_callback(packet);
packet_size_bytes = packet.size_bytes();
break;
}
default:
// Unrecognized PacketIndicator type, we've lost synchronization!
++bytes_consumed; // Consume the invalid packet indicator.
return StatusWithSize::DataLoss(bytes_consumed);
}
data = data.subspan(packet_size_bytes); // Pop off the HCI packet.
// Consume the packet indicator and the packet.
bytes_consumed += 1 + packet_size_bytes;
}
return StatusWithSize(bytes_consumed);
}
} // namespace pw::bluetooth_hci