/* This file completes the definitions of some types and functions
 * for communication, which are declared in comm-common.cvh.
 */
 
#ifndef __CIVLC_COMM__
#define __CIVLC_COMM__
#include <civlc.cvh>
#include<comm.cvh>
#include<seq.cvh>
#include<pointer.cvh>
#pragma CIVL ACSL 
/* *********************** Types *********************** */

/* A datatype representing a queue of messages.  All message
 * data is encapsulated inside this value; no external allocation
 * is used.  Completes the declaration of this structure type in 
 * civlc-common.h */ 
struct _queue {
  int length;
  $message messages[];
};


/* A global communicator datatype which must be operated by local communicators.
 * This communicator type has the same meaning as the communicator type
 * in MPI.  Completes the declaration of this type in civlc-common.h */
struct _gcomm {
  int nprocs; // number of processes
  $proc procs[]; // process references
  _Bool isInit[]; // if the local comm has been initiated
  $queue buf[][]; // message buffers
};

/* A datatype representing a local communicator which is used for 
 * operating global communicators. The local communicator type has 
 * a handle of a global communicator. This type represents for 
 * a set of processes which have ranks in common.
 * Completes the declaration of this type in civlc-common.h.
 */
struct _comm {
  int place;
  $gcomm gcomm;
};

/* *********************** Functions *********************** */

/* creates a new message, copying data from the specified buffer */
$atomic_f $message $message_pack(int source, int dest, int tag,
    const void *data, int size) {
  $message result;
  
  result.source = source;
  result.dest = dest;
  result.tag = tag;
  if (data != NULL && size > 0) {
    result.data = $bundle_pack(data, size);
  } else if (data == NULL)
    $assert(size == 0, "Attempt to pack a non-zero size message with a NULL pointer");
  result.size = size;
  return result;
}
  
/* returns the message source */ 
int $message_source($message message) {
  return message.source;
}

/* returns the message tag */
int $message_tag($message message) {
  return message.tag;
}

/* returns the message destination */ 
int $message_dest($message message) {
  return message.dest;
}

/* returns the message size */ 
int $message_size($message message) {
  return message.size;
}

/* transfers message data to buf, throwing exception if message
 * size exceeds specified size */
$atomic_f void $message_unpack($message message, void *buf, int size) {
  if (buf != NULL && message.size > 0) {
    $bundle_unpack(message.data, buf);
    $assert(message.size <= size, "Message of size %d exceeds the specified size %d.", 
	    message.size, size);
  }
  else if (buf == NULL)
    $assert(message.size == 0,
	    "Attempt to unpack a non-zero size message with a NULL pointer.");
}

$atomic_f $gcomm $gcomm_create($scope scope, int size){
  $gcomm gcomm=($gcomm)$malloc(scope, sizeof(struct _gcomm));
  $queue empty;
  
  empty.length=0;
  $seq_init(&empty.messages, 0, NULL);
  gcomm->nprocs=size;
  gcomm->procs=(($proc[size])$lambda(int i)$proc_null);
  gcomm->isInit=((_Bool[size])$lambda(int i)$false);
  gcomm->buf=(($queue[size][size])$lambda(int i,j) empty);
  return gcomm;
}

$atomic_f int $gcomm_destroy($gcomm gcomm, void * junkMsgs){
  int nprocs = gcomm->nprocs;
  int numJunks = 0;

  if(junkMsgs != NULL) {
    for (int i = 0; i < nprocs; i++) 
      for (int j = 0; j < nprocs; j++) {
	$queue queue = gcomm->buf[i][j];
	
	if (queue.length > 0)	
	  $seq_append(junkMsgs, queue.messages, queue.length);
      }
    numJunks = $seq_length(junkMsgs);
  }
  $free(gcomm); 
  return numJunks;
}

/*@ executes_when \true;
  @ depends_on \access(comm->gcomm, newcomm->gcomm); */
$atomic_f void $gcomm_dup($comm comm, $comm newcomm){
  $copy(newcomm->gcomm, comm->gcomm);
}

$atomic_f $comm $comm_create($scope scope, $gcomm gcomm, int place){
  $assert(!gcomm->isInit[place], "the place %d is already occupied in the global communicator!", place);

  $comm comm=($comm)$malloc(scope, sizeof(struct _comm));

  gcomm->procs[place]=$self;
  gcomm->isInit[place]=$true;
  comm->gcomm=gcomm;
  comm->place=place;
  return comm;
}

$atomic_f void $comm_destroy($comm comm){
  $free(comm);
}

/* Returns the place of the local communicator.  This is the same as the
 * place argument used to create the local communicator. */
$atomic_f int $comm_place($comm comm){
 return comm->place;
}

$atomic_f int $comm_size($comm comm){
 return comm->gcomm->nprocs;
}

#endif