【ADD】基于tcp长连接的封包和拆包基础方法

Author: chengxin

include/tigerapi/push_socket/push_frame_serialize.h

@@ -0,0 +1,30 @@
+#ifndef PUSH_FRAME_SERIALIZE_H
+#define PUSH_FRAME_SERIALIZE_H
+#include <vector>
+#include <string>
+
+namespace TIGER_API
+{
+	class PushFrameEncoder
+	{
+	public:
+		static std::vector<unsigned char> encode_frame(const std::string& packed_frame);
+	};
+
+	class PushFrameDecoder 
+	{
+	public:
+		PushFrameDecoder() = default;
+		~PushFrameDecoder() = default;
+
+		bool push_byte(unsigned char value);
+		uint64_t get_frame_size() const;
+
+	private:
+		uint64_t decode_varint();
+		std::vector<unsigned char> frame_header_buffer_;
+		uint64_t frame_len_ = 0;
+	};
+
+}
+#endif //PUSH_FRAME_SERIALIZE_H

src/push_socket/push_frame_serialize.cpp

@@ -0,0 +1,68 @@
+#include "tigerapi/push_socket/push_frame_serialize.h"
+#include <boost/endian/conversion.hpp>
+
+std::vector<unsigned char> TIGER_API::PushFrameEncoder::encode_frame(const std::string& packed_frame)
+{
+	if (packed_frame.empty())
+	{
+		return std::vector<unsigned char>();
+	}
+
+	size_t pack_size = packed_frame.size();
+	std::vector<unsigned char> pack_array;
+
+	unsigned char bits = pack_size & 0x7F;
+	pack_size >>= 7;
+	while (pack_size) 
+	{
+		unsigned char header_byte = 0x80 | bits;
+		pack_array.push_back(/*boost::endian::native_to_big(header_byte)*/header_byte);
+		bits = pack_size & 0x7F;
+		pack_size >>= 7;
+	}
+
+	pack_array.push_back(/*boost::endian::native_to_big(bits)*/bits);
+	pack_array.insert(pack_array.end(), packed_frame.begin(), packed_frame.end());
+	return pack_array;
+}
+
+bool TIGER_API::PushFrameDecoder::push_byte(unsigned char value)
+{
+	//逐个字节压入缓冲区(使用大端序列)
+	frame_header_buffer_.push_back(/*boost::endian::native_to_big(value)*/value);
+	if (!(value & 0x80))
+	{
+		//完整读取到包长度
+		frame_len_ = decode_varint();
+		frame_header_buffer_.clear();
+		//frame头部已经读取完毕
+		return true;
+	}
+	//frame头部还有数据，需要继续独取头部数据
+	return false;
+}
+
+uint64_t TIGER_API::PushFrameDecoder::get_frame_size() const
+{
+	return frame_len_;
+}
+
+uint64_t TIGER_API::PushFrameDecoder::decode_varint()
+{
+	const uint32_t mask = (1U << 32) - 1;  // 32位掩码
+	uint32_t result = 0;
+	int shift = 0;
+
+	for (const unsigned char& b : frame_header_buffer_)
+	{
+		result |= (static_cast<uint32_t>(b & 0x7F) << shift);
+		shift += 7;
+		if (shift >= 64) 
+		{
+			throw std::runtime_error("Too many bytes when decoding varint.");
+		}
+	}
+
+	result &= mask;  // 应用32位掩码
+	return result;
+}