void irecv_header()
{
/*
HPX_ASSERT(source_ != -1);
HPX_ASSERT(source_ != util::mpi_environment::rank());
*/
MPI_Irecv(
header_.data(), // data pointer
header_.data_size_, // number of elements
header_.type(), // MPI Datatype
MPI_ANY_SOURCE, // Source
0, // Tag
communicator_, // Communicator
&request_); // Request
}
bool readpacket() // watch performance, if bad, optimize with chunk reading
{
std::size_t offset = 0;
if( !m_synchronized )
{
bool first = true;
while( offset < 4 ) // watch performance, if bad, optimize with chunk reading
{
m_istream->read( &m_buf[offset], 1 );
if( first && m_istream->eof() ) { return false; }
first = false;
if( m_istream->eof() || m_istream->bad() ) { COMMA_THROW( comma::exception, "failed to synchronize, bad stream" ); }
unsigned char header_byte = reinterpret_cast<const unsigned char*>( m_header->data() )[offset];
offset = header_byte == header::sentinel_value[offset] ? offset + 1 : 0;
}
m_synchronized = true; // quick and dirty: synchronize once, should be enough
}
m_istream->read( &m_buf[0] + offset, header::size - offset );
if( m_istream->gcount() == 0 ) { return false; }
if( m_istream->eof() || m_istream->bad() || m_istream->gcount() != static_cast< int >( header::size - offset ) ) { COMMA_THROW( comma::exception, "failed to read packet header" ); }
if( !m_header->valid() )
{
m_synchronized = false;
COMMA_THROW( comma::exception, "invalid header (stream from laser went out of sync)" );
}
const std::size_t size = m_header->payload_size();
if( m_buf.size() < size + header::size )
{
m_buf.resize( size + header::size );
m_header = reinterpret_cast< const header* >( &m_buf[0] );
m_payload = &m_buf[0] + header::size;
}
m_istream->read( m_payload, size ); // todo: check payload size so that it does not go crazy?
if( m_istream->eof() ) { COMMA_THROW( comma::exception, "failed to read payload of size " << m_header->payload_size() << ", end of file" ); }
if( m_istream->bad() || m_istream->gcount() != int( size ) ) { COMMA_THROW( comma::exception, "failed to read payload of size " << m_header->payload_size() << ", bad stream" ); }
if( m_header->type() == header::fault_type ) { m_fault = *( reinterpret_cast< fault* >( m_payload ) ); }
return true;
}