allwpilib/networktables/cpp/lib/share/networktables2/connection/DataIOStream.cpp

#include "networktables2/connection/DataIOStream.h"
#include <memory>

///This is used in case NULL is passed so all logic calls to IOstream can continue to assume there is never a null pointer
class InertStream : public IOStream
{
protected:
	virtual int read(void* ptr, int numbytes) {return numbytes;}  //return success
	virtual int write(const void* ptr, int numbytes) {return numbytes;}
	virtual void flush() {}
	virtual void close() {}
};

static InertStream s_InertStream;

DataIOStream::DataIOStream(IOStream* _iostream) :
	iostream(_iostream)
{
}
DataIOStream::~DataIOStream()
{
	close();
	if (iostream!=&s_InertStream)
		delete iostream;
}

void DataIOStream::SetIOStream(IOStream* stream)
{
	IOStream *temp=iostream;
	iostream=stream ? stream : &s_InertStream;  //We'll never assign NULL
	if (temp!=&s_InertStream)
		delete temp;
}

void DataIOStream::close()
{
	iostream->close();
}

void DataIOStream::writeByte(uint8_t b)
{
	iostream->write(&b, 1);
}
void DataIOStream::write2BytesBE(uint16_t s)
{
	writeByte((uint8_t)(s >> 8));
	writeByte((uint8_t)s);
}
void DataIOStream::writeString(std::string& str)
{
	write2BytesBE(str.length());
	iostream->write(str.c_str(), str.length());
}
void DataIOStream::flush()
{
	iostream->flush();
}
uint8_t DataIOStream::readByte()
{
	uint8_t value;
	iostream->read(&value, 1);
	return value;
}
uint16_t DataIOStream::read2BytesBE()
{
	uint16_t value;
	value = readByte()<<8 | readByte();
	return value;
}
std::string* DataIOStream::readString()
{
	unsigned int byteLength = read2BytesBE();
	auto bytes = std::make_unique<char[]>(byteLength);
	iostream->read(bytes.get(), byteLength);
	return new std::string(bytes.get());//FIXME implement UTF-8 aware version
}