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  *                                                                                                                      *
  * ANTIKERNEL v0.1                                                                                                      *
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  * Copyright (c) 2012-2020 Andrew D. Zonenberg                                                                          *
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  /**
  	@file
  	@author Tom Verbeure
  	@brief Implementation of SCPILxiTransport
   */
  
  #ifdef HAS_LXI
  
  extern "C"
  {
  #include <lxi.h>
  }
  
  #include "scopehal.h"
  
  using namespace std;
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  // Construction / destruction
  
  bool SCPILxiTransport::m_lxi_initialized = false;
  
  SCPILxiTransport::SCPILxiTransport(const string& args)
  {
  	if (!m_lxi_initialized)
  	{
  		lxi_init();
  		m_lxi_initialized = true;
  	}
  
  	char hostname[128];
  	unsigned int port = 0;
  	if (2 != sscanf(args.c_str(), "%127[^:]:%u", hostname, &port))
  	{
  		//default if port not specified. VXI-11 is port 111, but liblxi fills that in for us.
  		m_hostname = args;
  		m_port = 0;
  	}
  	else
  	{
  		m_hostname = hostname;
  		m_port = port;
  	}
  
  	m_timeout = 1000;
  
  	LogDebug("Connecting to SCPI oscilloscope over VXI-11 at %s:%d\n", m_hostname.c_str(), m_port);
  
  	string instname = "inst0";
  	m_device = lxi_connect(&m_hostname[0], m_port, &instname[0], m_timeout, VXI11);
  
  	if (m_device == LXI_ERROR)
  	{
  		LogError("Couldn't connect to VXI-11 device\n");
  		return;
  	}
  
  	// When you issue a lxi_receive request, you need to specify the size of the receiving buffer.
  	// However, when the data received is larger than this buffer, liblxi simply discards this data.
  	// ReadReply and ReadRawData expect to be able to fetch received data piecemeal.
  	// The clunky solution is to have an intermediate buffer that is large enough to store all the
  	// data that could possible be returned by a scope.
  	// My Siglent oscilloscope can have a waveform of 140M samples, so I reserve 150M. However,
  	// I haven't been able to fetch waveforms larger than 1.4M (for reasons unknown.)
  	// Maybe we should reduce this number...
  	m_staging_buf_size = 150000000;
  	m_staging_buf = new unsigned char[m_staging_buf_size];
  	if (m_staging_buf == NULL)
  		return;
  	m_data_in_staging_buf = 0;
  	m_data_offset = 0;
  	m_data_depleted = false;
  }
  
  SCPILxiTransport::~SCPILxiTransport()
  {
  	delete[] m_staging_buf;
  }
  
  bool SCPILxiTransport::IsConnected()
  {
  	return (m_device != LXI_ERROR);
  }
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  // Actual transport code
  
  string SCPILxiTransport::GetTransportName()
  {
  	return "lxi";
  }
  
  string SCPILxiTransport::GetConnectionString()
  {
  	char tmp[256];
  	snprintf(tmp, sizeof(tmp), "%s:%u", m_hostname.c_str(), m_port);
  	return string(tmp);
  }
  
  bool SCPILxiTransport::SendCommand(const string& cmd)
  {
  	LogTrace("Sending %s\n", cmd.c_str());
  
  	//Need the cast when using liblxi versions prior to 63ea109 because they don't have "const" on the argument.
  	//It doesn't actually change the inputs, so safe to cast.
  	int result = lxi_send(m_device, const_cast<char*>(&cmd[0]), cmd.length(), m_timeout);
  
  	m_data_in_staging_buf = 0;
  	m_data_offset = 0;
  	m_data_depleted = false;
  
  	return (result != LXI_ERROR);
  }
  
  string SCPILxiTransport::ReadReply(bool endOnSemicolon)
  {
  	string ret;
  
  	if (!m_staging_buf)
  		return ret;
  
  	//FIXME: there *has* to be a more efficient way to do this...
  	char tmp = ' ';
  	while(true)
  	{
  		if (m_data_depleted)
  			break;
  		ReadRawData(1, (unsigned char *)&tmp);
  		if( (tmp == '\n') || ( (tmp == ';') && endOnSemicolon ) )
  			break;
  		else
  			ret += tmp;
  	}
  	LogTrace("Got %s\n", ret.c_str());
  	return ret;
  }
  
  void SCPILxiTransport::SendRawData(size_t len, const unsigned char* buf)
  {
  	// XXX: Should this reset m_data_depleted just like SendCommmand?
  
  	//Need the cast when using liblxi versions prior to 63ea109 because they don't have "const" on the argument.
  	//It doesn't actually change the inputs, so safe to cast.
  	lxi_send(m_device, const_cast<char*>(reinterpret_cast<const char*>(buf)), len, m_timeout);
  }
  
  size_t SCPILxiTransport::ReadRawData(size_t len, unsigned char* buf)
  {
  	// Data in the staging buffer is assumed to always be a consequence of a SendCommand request.
  	// Since we fetch all the reply data in one go, once all this data has been fetched, we mark
  	// the staging buffer as depleted and don't issue a new lxi_receive until a new SendCommand
  	// is issued.
  
  	if (!m_staging_buf)
  		return 0;
  
  	if (!m_data_depleted)
  	{
  		if (m_data_in_staging_buf == 0)
  		{
  			m_data_in_staging_buf = lxi_receive(m_device, (char *)m_staging_buf, m_staging_buf_size, m_timeout);
  			if (m_data_in_staging_buf == LXI_ERROR)
  				m_data_in_staging_buf = 0;
  			m_data_offset = 0;
  		}
  
  		unsigned int data_left = m_data_in_staging_buf - m_data_offset;
  		if (data_left > 0)
  		{
  			int nr_bytes = len > data_left ? data_left : len;
  
  			memcpy(buf, m_staging_buf + m_data_offset, nr_bytes);
  
  			m_data_offset += nr_bytes;
  		}
  
  		if (m_data_offset == m_data_in_staging_buf)
  				m_data_depleted = true;
  	}
  	else
  	{
  		// When this happens, the SCPIDevice is fetching more data from device than what
  		// could be expected from the SendCommand that was issued.
  		LogDebug("ReadRawData: data depleted.\n");
  		return 0;
  	}
  
  	return len;
  }
  
  bool SCPILxiTransport::IsCommandBatchingSupported()
  {
  	return false;
  }
  
  #endif
  