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//
// Copyright 2010 Ettus Research LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
#ifndef INCLUDED_LIBUHD_TRANSPORT_VRT_PACKET_HANDLER_HPP
#define INCLUDED_LIBUHD_TRANSPORT_VRT_PACKET_HANDLER_HPP
#include <uhd/types/io_type.hpp>
#include <uhd/types/otw_type.hpp>
#include <uhd/types/metadata.hpp>
#include <uhd/transport/vrt.hpp>
#include <uhd/transport/convert_types.hpp>
#include <uhd/transport/zero_copy.hpp>
#include <boost/asio/buffer.hpp>
#include <boost/function.hpp>
#include <iostream>
namespace vrt_packet_handler{
/***********************************************************************
* vrt packet handler for recv
**********************************************************************/
struct recv_state{
//init the expected seq number
size_t next_packet_seq;
//state variables to handle fragments
uhd::transport::managed_recv_buffer::sptr managed_buff;
boost::asio::const_buffer copy_buff;
size_t fragment_offset_in_samps;
recv_state(void){
//first expected seq is zero
next_packet_seq = 0;
//initially empty copy buffer
copy_buff = boost::asio::buffer("", 0);
}
};
typedef boost::function<void(uhd::transport::managed_recv_buffer::sptr)> recv_cb_t;
static inline void recv_cb_nop(uhd::transport::managed_recv_buffer::sptr){
/* NOP */
}
static inline size_t recv(
recv_state &state,
const boost::asio::mutable_buffer &buff,
uhd::rx_metadata_t &metadata,
const uhd::io_type_t &io_type,
const uhd::otw_type_t &otw_type,
double tick_rate,
uhd::transport::zero_copy_if::sptr zc_iface,
size_t vrt_header_offset_words32 = 0,
const recv_cb_t& recv_cb = &recv_cb_nop
){
////////////////////////////////////////////////////////////////
// Perform the recv
////////////////////////////////////////////////////////////////
{
//perform a receive if no rx data is waiting to be copied
if (boost::asio::buffer_size(state.copy_buff) == 0){
state.fragment_offset_in_samps = 0;
state.managed_buff = zc_iface->get_recv_buff();
recv_cb(state.managed_buff);
}
//otherwise flag the metadata to show that is is a fragment
else{
metadata = uhd::rx_metadata_t();
goto vrt_recv_copy_convert;
}
}
////////////////////////////////////////////////////////////////
// Unpack the vrt header
////////////////////////////////////////////////////////////////
{
size_t num_packet_words32 = state.managed_buff->size()/sizeof(boost::uint32_t);
if (num_packet_words32 <= vrt_header_offset_words32){
state.copy_buff = boost::asio::buffer("", 0);
goto vrt_recv_copy_convert; //must exit here after setting the buffer
}
const boost::uint32_t *vrt_hdr = state.managed_buff->cast<const boost::uint32_t *>() + vrt_header_offset_words32;
size_t num_header_words32_out, num_payload_words32_out, packet_count_out;
uhd::transport::vrt::unpack(
metadata, //output
vrt_hdr, //input
num_header_words32_out, //output
num_payload_words32_out, //output
num_packet_words32, //input
packet_count_out, //output
tick_rate
);
//handle the packet count / sequence number
if (packet_count_out != state.next_packet_seq){
std::cerr << "S" << (packet_count_out - state.next_packet_seq)%16;
}
state.next_packet_seq = (packet_count_out+1)%16;
//setup the buffer to point to the data
state.copy_buff = boost::asio::buffer(
vrt_hdr + num_header_words32_out,
num_payload_words32_out*sizeof(boost::uint32_t)
);
}
////////////////////////////////////////////////////////////////
// Perform copy-convert into buffer
////////////////////////////////////////////////////////////////
vrt_recv_copy_convert:{
size_t bytes_per_item = (otw_type.width * 2) / 8;
//extract the number of samples available to copy
//and a pointer into the usrp2 received items memory
size_t bytes_available = boost::asio::buffer_size(state.copy_buff);
size_t num_samps = std::min(
boost::asio::buffer_size(buff)/io_type.size,
bytes_available/bytes_per_item
);
//setup the fragment flags and offset
metadata.more_fragments = boost::asio::buffer_size(buff)/io_type.size < num_samps;
metadata.fragment_offset = state.fragment_offset_in_samps;
state.fragment_offset_in_samps += num_samps; //set for next time
//copy-convert the samples from the recv buffer
uhd::transport::convert_otw_type_to_io_type(
boost::asio::buffer_cast<const void*>(state.copy_buff), otw_type,
boost::asio::buffer_cast<void*>(buff), io_type,
num_samps
);
//update the rx copy buffer to reflect the bytes copied
size_t bytes_copied = num_samps*bytes_per_item;
state.copy_buff = boost::asio::buffer(
boost::asio::buffer_cast<const boost::uint8_t*>(state.copy_buff) + bytes_copied,
bytes_available - bytes_copied
);
return num_samps;
}
}
} //namespace vrt_packet_handler
#endif /* INCLUDED_LIBUHD_TRANSPORT_VRT_PACKET_HANDLER_HPP */
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