/* socketio.c */


/*
 * Vis5D system for visualizing five dimensional gridded data sets.
 * Copyright (C) 1990 - 2000 Bill Hibbard, Johan Kellum, Brian Paul,
 * Dave Santek, and Andre Battaiola.
 *
 * 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 2 of the License, or
 * (at your option) any later version.
 *
 * As a special exception to the terms of the GNU General Public
 * License, you are permitted to link Vis5D with (and distribute the
 * resulting source and executables) the LUI library (copyright by
 * Stellar Computer Inc. and licensed for distribution with Vis5D),
 * the McIDAS library, and/or the NetCDF library, where those
 * libraries are governed by the terms of their own licenses.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include "../config.h"

/* socket communications module */

#include <string.h>
#include <unistd.h>




/*** receive_data *****************************************************
   Receive a block of data by repeatedly reading from a socket.  This
   function will block the process if data is not available.
   Input:  socket - socket to read from
            buffer - pointer to data buffer
           bytes - how many bytes to read into buffer
   Return:  number of bytes received.  This will always either be
            the same as the bytes requested or 0 if the connection
            was lost.
**********************************************************************/
int receive_data( int socket, void *buffer, int bytes )
{
   int sofar, remaining, len;
   char *buf;

   buf = buffer;
   sofar = 0;
   remaining = bytes;
   do {
      len = read( socket, buf + sofar, remaining);
      if (len<=0) return 0;
      sofar += len;
      remaining -= len;
   } while (remaining>0);
   return bytes;
}




/*** send_data ********************************************************
   Send a block of data by repeatedly writing to a socket.
   Input:  socket - socket to write to
           buffer - pointer to data to send
           bytes - number of bytes to send from buffer
**********************************************************************/
void send_data( int socket, void *buffer, int bytes )
{
   int sofar, remaining, len;
   char *buf;

   buf = buffer;
   sofar = 0;
   remaining = bytes;
   do {
      len = write( socket, buf + sofar, remaining);
      sofar += len;
      remaining -= len;
   } while (remaining>0);

}




/*** receive_int ******************************************************
   Receive a 32-bit integer through a socket.  This function will
   block if the data is not available.
   Input:  socket - the socket to receive the integer from.
           i - pointer to integer to put result into.
   Output:  i will have the value received
   Return:  0 if the connection was lost
            non-zero if successful
**********************************************************************/
int receive_int( int socket, int *i )
{
   return receive_data( socket, i, sizeof(int) );
}




/*** send_int *********************************************************
   Send a 32-bit integer through a socket.
   Input:  socket - the socket to send on.
           i - the integer to send
   Output:  none.
**********************************************************************/
void send_int( int socket, int i )
{
   send_data( socket, &i, sizeof(int) );
}





/*** receive_float ****************************************************
   Receive a 32-bit float through a socket.  This function will
   block if the data is not available.
   Input:  socket - the socket to receive the integer from.
           x - pointer to float to put result into.
   Output:  i will have the value received
   Return:  0 if the connection was lost
            non-zero if successful
**********************************************************************/
int receive_float( int socket, float *x )
{
   return receive_data( socket, x, sizeof(float) );
}





/*** send_float *********************************************************
   Send a 32-bit float through a socket.
   Input:  socket - the socket to send on.
           x - the float to send
   Output:  none.
**********************************************************************/
void send_float( int socket, float x )
{
   float y;

   y = (float) x;
   send_data( socket, &y, sizeof(float) );
}




/*** receive_str ******************************************************
   Receive a character string.  This function will block if the data
   is not available.
   Input:  socket - the socket to receive the string from.
           str - pointer to char array to put result into.  It is
                 assumed to be of sufficient size.
   Output:  str will have the string received
   Return:  0 if the connection was lost
            non-zero if successful
**********************************************************************/
int receive_str( int socket, char str[] )
{
   int len;

   if ( receive_int(socket, &len) ) {
      if ( receive_data(socket, str, len)==len ) {
         str[len] = '\0';
         return 1;
      }
   }
   return 0;
}




/*** send_str *********************************************************
   Send a character string through a socket.
   Input:  socket - the socket to send on.
           str - the string to send
   Output:  none.
**********************************************************************/
void send_str( int socket, char str[] )
{
   int len;

   len = strlen( str );
   send_int( socket, len );
   send_data( socket, str, len );
}