Haxe Lib Datachannel

lib/datachannel/cpp/libdatachannel/include/rtc/nalunit.hpp

@@ -0,0 +1,197 @@
+/**
+ * Copyright (c) 2020 Filip Klembara (in2core)
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef RTC_NAL_UNIT_H
+#define RTC_NAL_UNIT_H
+
+#if RTC_ENABLE_MEDIA
+
+#include "common.hpp"
+
+#include <vector>
+#include <cassert>
+
+namespace rtc {
+
+#pragma pack(push, 1)
+
+/// Nalu header
+struct RTC_CPP_EXPORT NalUnitHeader {
+	uint8_t _first = 0;
+
+	bool forbiddenBit() const { return _first >> 7; }
+	uint8_t nri() const { return _first >> 5 & 0x03; }
+	uint8_t idc() const { return _first & 0x60; }
+	uint8_t unitType() const { return _first & 0x1F; }
+
+	void setForbiddenBit(bool isSet) { _first = (_first & 0x7F) | (isSet << 7); }
+	void setNRI(uint8_t nri) { _first = (_first & 0x9F) | ((nri & 0x03) << 5); }
+	void setUnitType(uint8_t type) { _first = (_first & 0xE0) | (type & 0x1F); }
+};
+
+/// Nalu fragment header
+struct RTC_CPP_EXPORT NalUnitFragmentHeader {
+	uint8_t _first = 0;
+
+	bool isStart() const { return _first >> 7; }
+	bool reservedBit6() const { return (_first >> 5) & 0x01; }
+	bool isEnd() const { return (_first >> 6) & 0x01; }
+	uint8_t unitType() const { return _first & 0x1F; }
+
+	void setStart(bool isSet) { _first = (_first & 0x7F) | (isSet << 7); }
+	void setEnd(bool isSet) { _first = (_first & 0xBF) | (isSet << 6); }
+	void setReservedBit6(bool isSet) { _first = (_first & 0xDF) | (isSet << 5); }
+	void setUnitType(uint8_t type) { _first = (_first & 0xE0) | (type & 0x1F); }
+};
+
+#pragma pack(pop)
+
+enum NalUnitStartSequenceMatch {
+	NUSM_noMatch,
+	NUSM_firstZero,
+	NUSM_secondZero,
+	NUSM_thirdZero,
+	NUSM_shortMatch,
+	NUSM_longMatch
+};
+
+static const size_t H264_NAL_HEADER_SIZE = 1;
+static const size_t H265_NAL_HEADER_SIZE = 2;
+
+struct NalUnitFragmentA;
+
+/// NAL unit
+struct RTC_CPP_EXPORT NalUnit : binary {
+	static std::vector<binary> GenerateFragments(const std::vector<NalUnit> &nalus,
+	                                             size_t maxFragmentSize);
+
+	enum class Separator {
+		Length = RTC_NAL_SEPARATOR_LENGTH, // first 4 bytes are NAL unit length
+		LongStartSequence = RTC_NAL_SEPARATOR_LONG_START_SEQUENCE,   // 0x00, 0x00, 0x00, 0x01
+		ShortStartSequence = RTC_NAL_SEPARATOR_SHORT_START_SEQUENCE, // 0x00, 0x00, 0x01
+		StartSequence = RTC_NAL_SEPARATOR_START_SEQUENCE, // LongStartSequence or ShortStartSequence
+	};
+
+	static NalUnitStartSequenceMatch StartSequenceMatchSucc(NalUnitStartSequenceMatch match,
+	                                                 std::byte _byte, Separator separator);
+
+	enum class Type { H264, H265 };
+
+	NalUnit(const NalUnit &unit) = default;
+	NalUnit(size_t size, bool includingHeader = true, Type type = Type::H264)
+	    : binary(size + (includingHeader ? 0
+	                                     : (type == Type::H264 ? H264_NAL_HEADER_SIZE
+	                                                           : H265_NAL_HEADER_SIZE))) {}
+	NalUnit(binary &&data) : binary(std::move(data)) {}
+	NalUnit(Type type = Type::H264)
+	    : binary(type == Type::H264 ? H264_NAL_HEADER_SIZE : H265_NAL_HEADER_SIZE) {}
+	template <typename Iterator> NalUnit(Iterator begin_, Iterator end_) : binary(begin_, end_) {}
+
+	bool forbiddenBit() const { return header()->forbiddenBit(); }
+	uint8_t nri() const { return header()->nri(); }
+	uint8_t unitType() const { return header()->unitType(); }
+
+	binary payload() const {
+		assert(size() >= 1);
+		return {begin() + 1, end()};
+	}
+
+	void setForbiddenBit(bool isSet) { header()->setForbiddenBit(isSet); }
+	void setNRI(uint8_t nri) { header()->setNRI(nri); }
+	void setUnitType(uint8_t type) { header()->setUnitType(type); }
+
+	void setPayload(binary payload) {
+		assert(size() >= 1);
+		erase(begin() + 1, end());
+		insert(end(), payload.begin(), payload.end());
+	}
+
+	std::vector<NalUnitFragmentA> generateFragments(size_t maxFragmentSize) const;
+
+protected:
+	const NalUnitHeader *header() const {
+		assert(size() >= 1);
+		return reinterpret_cast<const NalUnitHeader *>(data());
+	}
+
+	NalUnitHeader *header() {
+		assert(size() >= 1);
+		return reinterpret_cast<NalUnitHeader *>(data());
+	}
+};
+
+/// Nal unit fragment A
+struct RTC_CPP_EXPORT NalUnitFragmentA : NalUnit {
+	// For backward compatibility, do not use
+	[[deprecated]] static std::vector<shared_ptr<NalUnitFragmentA>>
+	fragmentsFrom(shared_ptr<NalUnit> nalu, uint16_t maxFragmentSize);
+
+	enum class FragmentType { Start, Middle, End };
+
+	NalUnitFragmentA(FragmentType type, bool forbiddenBit, uint8_t nri, uint8_t unitType,
+	                 binary data);
+
+	uint8_t unitType() const { return fragmentHeader()->unitType(); }
+
+	binary payload() const {
+		assert(size() >= 2);
+		return {begin() + 2, end()};
+	}
+
+	FragmentType type() const {
+		if (fragmentHeader()->isStart()) {
+			return FragmentType::Start;
+		} else if (fragmentHeader()->isEnd()) {
+			return FragmentType::End;
+		} else {
+			return FragmentType::Middle;
+		}
+	}
+
+	void setUnitType(uint8_t type) { fragmentHeader()->setUnitType(type); }
+
+	void setPayload(binary payload) {
+		assert(size() >= 2);
+		erase(begin() + 2, end());
+		insert(end(), payload.begin(), payload.end());
+	}
+
+	void setFragmentType(FragmentType type);
+
+protected:
+	const uint8_t nal_type_fu_A = 28;
+
+	NalUnitHeader *fragmentIndicator() { return reinterpret_cast<NalUnitHeader *>(data()); }
+
+	const NalUnitHeader *fragmentIndicator() const {
+		return reinterpret_cast<const NalUnitHeader *>(data());
+	}
+
+	NalUnitFragmentHeader *fragmentHeader() {
+		return reinterpret_cast<NalUnitFragmentHeader *>(fragmentIndicator() + 1);
+	}
+
+	const NalUnitFragmentHeader *fragmentHeader() const {
+		return reinterpret_cast<const NalUnitFragmentHeader *>(fragmentIndicator() + 1);
+	}
+};
+
+// For backward compatibility, do not use
+class [[deprecated]] RTC_CPP_EXPORT NalUnits : public std::vector<shared_ptr<NalUnit>> {
+public:
+	static const uint16_t defaultMaximumFragmentSize =
+	    uint16_t(RTC_DEFAULT_MTU - 12 - 8 - 40); // SRTP/UDP/IPv6
+
+	std::vector<shared_ptr<binary>> generateFragments(uint16_t maxFragmentSize);
+};
+
+} // namespace rtc
+
+#endif /* RTC_ENABLE_MEDIA */
+
+#endif /* RTC_NAL_UNIT_H */