Method read

external/floppybridge/src/SerialIO.cpp:893–951

Attempts to read some data from the port. Returns how much it actually read. Returns how much it actually read

// Attempts to read some data from the port.  Returns how much it actually read.
// Returns how much it actually read
unsigned int SerialIO::read(void* data, unsigned int dataLength) {
	if ((data == nullptr) || (dataLength == 0)) return 0;
	if (!isPortOpen()) return 0;

#ifdef FTDI_D2XX_AVAILABLE
	if (m_ftdi.isOpen()) {
		m_ftdi.FT_SetTimeouts(m_readTimeout + (m_readTimeoutMultiplier * dataLength), m_writeTimeout + (m_writeTimeoutMultiplier * dataLength));

		DWORD dataRead = 0;
		if (m_ftdi.FT_Read((LPVOID)data, dataLength, &dataRead) != FTDI::FT_STATUS::FT_OK) dataRead = 0;
		return dataRead;
	}
#endif

#ifdef _WIN32
	DWORD read = 0;
	if (!ReadFile(m_portHandle, data, dataLength, &read, NULL)) read = 0;
	return read;
#else
	unsigned int totalTime = m_readTimeout + (m_readTimeoutMultiplier * dataLength);

	struct timeval timeout;
	timeout.tv_sec = totalTime / 1000;
	timeout.tv_usec = (totalTime - (timeout.tv_sec * 1000)) * 1000;

	size_t read = 0;
	unsigned char* buffer = (unsigned char*)data;

	fd_set fds;
	FD_ZERO(&fds);
	FD_SET(m_portHandle, &fds);

	while (read < dataLength) {
		if ((timeout.tv_sec < 1) && (timeout.tv_usec < 1)) {
			break;
		}

		int result = select(m_portHandle + 1, &fds, NULL, NULL, &timeout);

		if (result < 0) {
			if (errno == EINTR || errno == EAGAIN) continue; else return 0;
		}
		else if (result == 0) break;
		result = ::read(m_portHandle, buffer, dataLength - read);

		if (result < 0) {
			if (errno == EINTR || errno == EAGAIN) continue; else return 0;
		}
		read += result;
		buffer += result;
	}

	return read;


#endif

	return 0;