breadcast/breadcast-caststream-sys/vendor/openscreen/cast/streaming/impl/packet_util.h
Breadway 8c745d18e0
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Implement Cast Streaming mirroring, DLNA casting, daemon+GUI, and breadd integration
Builds out the full v1 scope: a vendored+patched openscreen subset for
low-latency Cast Streaming (Mirroring receiver 0F5096E8) alongside the
existing Cast V2/HLS and new DLNA/AVTransport casting paths, breadcastd's
Idle/Casting state machine with a private IPC socket, the breadcast GTK4
popup as a thin IPC client, and bread.cast.*/bread.command.cast.* breadd
integration (device discovery, start/stop, mirroring lifecycle events).
Also adds bakery/systemd/Forgejo CI packaging.

Validated end-to-end against a real Chromecast/Google TV: negotiated
Cast Streaming session, live pipeline playback, and daemon+GUI click-to-cast/
stop through the actual popup.
2026-08-03 09:07:21 +08:00

60 lines
2.1 KiB
C++

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CAST_STREAMING_IMPL_PACKET_UTIL_H_
#define CAST_STREAMING_IMPL_PACKET_UTIL_H_
#include <utility>
#include "cast/streaming/ssrc.h"
#include "platform/base/span.h"
#include "util/big_endian.h"
#include "util/osp_logging.h"
namespace openscreen::cast {
// Reads a field from the start of the given span and advances the span to point
// just after the field.
template <typename Integer>
inline Integer ConsumeField(ByteView& in) {
OSP_CHECK_GE(in.size(), sizeof(Integer));
const Integer result = ReadBigEndian<Integer>(in.data());
in = in.subspan(sizeof(Integer));
return result;
}
// Writes a field at the start of the given span and advances the span to point
// just after the field.
template <typename Integer>
inline void AppendField(Integer value, ByteBuffer& out) {
WriteBigEndian<Integer>(value, out.data());
out = out.subspan(sizeof(Integer));
}
// Returns a bitmask for a field having the given number of bits. For example,
// FieldBitmask<uint8_t>(5) returns 0b00011111.
template <typename Integer>
constexpr Integer FieldBitmask(unsigned field_size_in_bits) {
return (Integer{1} << field_size_in_bits) - 1;
}
// Reserves `num_bytes` from the beginning of the given span, returning the
// reserved space.
inline ByteBuffer ReserveSpace(int num_bytes, ByteBuffer& out) {
const ByteBuffer reserved = out.subspan(0, num_bytes);
out = out.subspan(num_bytes);
return reserved;
}
// Performs a quick-scan of the packet data for the purposes of routing it to an
// appropriate parser. Identifies whether the packet is a RTP packet, RTCP
// packet, or unknown; and provides the originator's SSRC. This only performs a
// very quick scan of the packet data, and does not guarantee that a full parse
// will later succeed.
enum class ApparentPacketType { UNKNOWN, RTP, RTCP };
std::pair<ApparentPacketType, Ssrc> InspectPacketForRouting(ByteView packet);
} // namespace openscreen::cast
#endif // CAST_STREAMING_IMPL_PACKET_UTIL_H_