rcpp_framework/libs/brynet/base/Packet.hpp

#pragma once

#include <brynet/base/NonCopyable.hpp>
#include <brynet/base/endian/Endian.hpp>
#include <cstdint>
#include <cstring>
#include <stdexcept>
#include <string>

class BasePacketWriter : public NonCopyable {
public:
	BasePacketWriter(char *buffer,
			size_t len,
			bool useBigEndian = false,
			bool isAutoMalloc = false) :
			mIsAutoMalloc(isAutoMalloc),
			mBigEndian(useBigEndian) {
		mMaxLen = len;
		mPos = 0;
		mBuffer = buffer;
		mMallocBuffer = nullptr;
	}

	virtual ~BasePacketWriter() {
		if (mMallocBuffer != nullptr) {
			free(mMallocBuffer);
			mMallocBuffer = nullptr;
		}
	}

	void init() {
		mPos = 0;
	}

	size_t getMaxLen() const {
		return mMaxLen;
	}

	size_t getPos() const {
		return mPos;
	}

	const char *getData() const {
		return mBuffer;
	}

	bool isAutoGrow() const {
		return mIsAutoMalloc;
	}

	bool writeBool(bool value) {
		static_assert(sizeof(bool) == sizeof(int8_t), "");
		return writeBuffer((char *)&value, sizeof(value));
	}
	bool writeINT8(int8_t value) {
		return writeBuffer((char *)&value, sizeof(value));
	}
	bool writeUINT8(uint8_t value) {
		return writeBuffer((char *)&value, sizeof(value));
	}
	bool writeINT16(int16_t value) {
		value = hostToNetwork16(value, mBigEndian);
		return writeBuffer((char *)&value, sizeof(value));
	}
	bool writeUINT16(uint16_t value) {
		value = hostToNetwork16(value, mBigEndian);
		return writeBuffer((char *)&value, sizeof(value));
	}
	bool writeINT32(int32_t value) {
		value = hostToNetwork32(value, mBigEndian);
		return writeBuffer((char *)&value, sizeof(value));
	}
	bool writeUINT32(uint32_t value) {
		value = hostToNetwork32(value, mBigEndian);
		return writeBuffer((char *)&value, sizeof(value));
	}
	bool writeINT64(int64_t value) {
		value = hostToNetwork64(value, mBigEndian);
		return writeBuffer((char *)&value, sizeof(value));
	}
	bool writeUINT64(uint64_t value) {
		value = hostToNetwork64(value, mBigEndian);
		return writeBuffer((char *)&value, sizeof(value));
	}

	bool writeBinary(const std::string &binary) {
		return writeBuffer(binary.c_str(), binary.size());
	}
	bool writeBinary(const char *binary, size_t binaryLen) {
		return writeBuffer(binary, binaryLen);
	}
	bool writeBuffer(const char *buffer, size_t len) {
		growBuffer(len);

		if (mMaxLen < (mPos + len)) {
			return false;
		}

		memcpy(mBuffer + mPos, buffer, len);
		mPos += len;
		return true;
	}

	BasePacketWriter &operator<<(const bool &v) {
		writeBool(v);
		return *this;
	}
	BasePacketWriter &operator<<(const uint8_t &v) {
		writeUINT8(v);
		return *this;
	}
	BasePacketWriter &operator<<(const int8_t &v) {
		writeINT8(v);
		return *this;
	}
	BasePacketWriter &operator<<(const int16_t &v) {
		writeINT16(v);
		return *this;
	}
	BasePacketWriter &operator<<(const uint16_t &v) {
		writeUINT16(v);
		return *this;
	}
	BasePacketWriter &operator<<(const int32_t &v) {
		writeINT32(v);
		return *this;
	}
	BasePacketWriter &operator<<(const uint32_t &v) {
		writeUINT32(v);
		return *this;
	}
	BasePacketWriter &operator<<(const int64_t &v) {
		writeINT64(v);
		return *this;
	}
	BasePacketWriter &operator<<(const uint64_t &v) {
		writeUINT64(v);
		return *this;
	}
	BasePacketWriter &operator<<(const char *const &v) {
		writeBinary(v);
		return *this;
	}
	BasePacketWriter &operator<<(const std::string &v) {
		writeBinary(v);
		return *this;
	}

private:
	// 为了避免直接<<导致没有指定字节序导致隐藏BUG,因为此函数设置为私有
	template <typename T>
	BasePacketWriter &operator<<(const T &v) {
		static_assert(!std::is_pointer<T>::value, "T must is't a pointer");
		static_assert(std::is_class<T>::value, "T must a class or struct type");
		static_assert(std::is_pod<T>::value, "T must a pod type");
		writeBuffer((const char *)&v, sizeof(v));
		return *this;
	}

	template <typename Arg1, typename... Args>
	void writev(const Arg1 &arg1, const Args &...args) {
		this->operator<<(arg1);
		writev(args...);
	}

	void writev() {
	}

protected:
	void growBuffer(size_t len) {
		if (!mIsAutoMalloc || (mPos + len) <= mMaxLen) {
			return;
		}

		auto newBuffer = (char *)malloc(mMaxLen + len);
		if (newBuffer == nullptr) {
			return;
		}

		memcpy(newBuffer, mBuffer, mPos);

		if (mMallocBuffer != nullptr) {
			free(mMallocBuffer);
			mMallocBuffer = nullptr;
		}

		mMaxLen += len;
		mMallocBuffer = newBuffer;
		mBuffer = newBuffer;
	}

protected:
	const bool mIsAutoMalloc;
	bool mBigEndian;
	size_t mPos;
	size_t mMaxLen;
	char *mBuffer;
	char *mMallocBuffer;
};

class BasePacketReader {
public:
	BasePacketReader(const char *buffer,
			size_t len,
			bool useBigEndian = false) :
			mBigEndian(useBigEndian),
			mSize(len) {
		mPos = 0;
		mSavedPos = 0;
		mBuffer = buffer;
	}

	virtual ~BasePacketReader() = default;

	void useBigEndian() {
		mBigEndian = true;
	}

	void useLittleEndian() {
		mBigEndian = false;
	}

	void savePos() {
		mSavedPos = mPos;
	}

	size_t savedPos() const {
		return mSavedPos;
	}

	size_t getLeft() const {
		if (mPos > mSize) {
			throw std::out_of_range("current pos is greater than max len");
		}
		return mSize - mPos;
	}

	bool enough(size_t len) const {
		if (mPos > mSize) {
			return false;
		}
		return (mSize - mPos) >= len;
	}

	const char *begin() const {
		return mBuffer;
	}

	const char *currentBuffer() const {
		return mBuffer + mPos;
	}

	void consumeAll() {
		mPos = mSize;
		savePos();
	}

	size_t currentPos() const {
		return mPos;
	}

	size_t size() const {
		return mSize;
	}

	void addPos(size_t diff) {
		const auto tmpPos = mPos + diff;
		if (tmpPos > mSize) {
			throw std::out_of_range("diff is to big");
		}

		mPos = tmpPos;
	}

	bool readBool() {
		static_assert(sizeof(bool) == sizeof(int8_t), "");
		bool value = false;
		read(value);
		return value;
	}
	int8_t readINT8() {
		int8_t value = 0;
		read(value);
		return value;
	}
	uint8_t readUINT8() {
		uint8_t value = 0;
		read(value);
		return value;
	}
	int16_t readINT16() {
		int16_t value = 0;
		read(value);
		return networkToHost16(value, mBigEndian);
	}
	uint16_t readUINT16() {
		uint16_t value = 0;
		read(value);
		return networkToHost16(value, mBigEndian);
	}
	int32_t readINT32() {
		int32_t value = 0;
		read(value);
		return networkToHost32(value, mBigEndian);
	}
	uint32_t readUINT32() {
		uint32_t value = 0;
		read(value);
		return networkToHost32(value, mBigEndian);
	}
	int64_t readINT64() {
		int64_t value = 0;
		read(value);
		return networkToHost64(value, mBigEndian);
	}
	uint64_t readUINT64() {
		uint64_t value = 0;
		read(value);
		return networkToHost64(value, mBigEndian);
	}

private:
	// 为了避免直接read(uintXXX)导致没有指定字节序造成隐患BUG,因为此函数设置为私有
	template <typename T>
	void read(T &value) {
		static_assert(std::is_same<T, typename std::remove_pointer<T>::type>::value,
				"T must a normal type");
		static_assert(std::is_pod<T>::value,
				"T must a pod type");

		if ((mPos + sizeof(value)) > mSize) {
			throw std::out_of_range("T size is to big");
		}

		value = *(T *)(mBuffer + mPos);
		mPos += sizeof(value);
	}

protected:
	bool mBigEndian;
	const size_t mSize;
	const char *mBuffer;
	size_t mPos;
	size_t mSavedPos;
};

template <size_t SIZE>
class AutoMallocPacket : public BasePacketWriter {
public:
	explicit AutoMallocPacket(bool useBigEndian = false,
			bool isAutoMalloc = false) :
			BasePacketWriter(mData, SIZE, useBigEndian, isAutoMalloc) {}

private:
	char mData[SIZE];
};

using BigPacket = AutoMallocPacket<32 * 1024>;