/* -*- c-file-style: "GNU" -*- */
/*
 * Copyright (C) CNRS, INRIA, Université Bordeaux 1, Télécom SudParis
 * See COPYING in top-level directory.
 */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <mpi.h>

#define LEN      1024
#define LOOPS    10

static int comm_rank = -1;
static int comm_size = -1;
static char host_name[1024] = "";

static unsigned char *main_buffer = NULL;

/* fill the buffer */
void fill_buffer(unsigned char* buffer, int buffer_size) {
  int i;
  for (i = 0; i < buffer_size; i++)
    buffer[i] = 'a' + (i % 26);
}

/* fill the buffer with 0 */
void zero_buffer(unsigned char* buffer, int buffer_size) {
  int i;
  for (i = 0; i < buffer_size; i++)
    buffer[i] = 0;
}

/* check wether the buffer contains errornous data
 * return 1 if it contains an error
 */
int check_buffer(unsigned char* buffer, int buffer_size) {
  int i;
  for (i = 0; i < buffer_size; i++)
    if (buffer[i] != 'a' + (i % 26))
      return 1;
  return 0;
}

/* 'Compute' for a fixed duration */
void compute(unsigned usec) {
  double t1, t2;
  t1 = MPI_Wtime();
  do {
    t2 = MPI_Wtime();
  } while (((t2 - t1) * 1e6) < (double) usec);
}

int main(int argc, char **argv) {
  int ping_side;
  int rank_dst;
  int start_len = LEN;
  int iterations = LOOPS;

  MPI_Init(&argc, &argv);

  MPI_Comm_size(MPI_COMM_WORLD, &comm_size);
  MPI_Comm_rank(MPI_COMM_WORLD, &comm_rank);

  if (gethostname(host_name, 1023) < 0) {
    perror("gethostname");
    exit(1);
  }

  if (comm_size != 2) {
    fprintf(stderr, "This program requires 2 MPI processes, aborting...\n");
    goto out;
  }

  fprintf(stdout, "(%s): My rank is %d\n", host_name, comm_rank);

  ping_side = !(comm_rank & 1);
  rank_dst = ping_side ? (comm_rank | 1) : (comm_rank & ~1);

  main_buffer = malloc(start_len);
  fill_buffer(main_buffer, start_len);

  MPI_Barrier(MPI_COMM_WORLD);

  /* Test */
  if (ping_side) {
    int size = start_len;
    int nb_samples;

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      fill_buffer(main_buffer, size);
      MPI_Send(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
      MPI_Recv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
               MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Send/MPI_Recv failed !\n", ping_side);
        goto out;
      }
    }
    fprintf(stderr, "[%d] MPI_Send/MPI_Recv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      fill_buffer(main_buffer, size);
      MPI_Send(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
      MPI_Recv(main_buffer, size, MPI_CHAR, MPI_ANY_SOURCE, 0, MPI_COMM_WORLD,
               MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYSRC failed !\n", ping_side);
        goto out;
      }
    }
    fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYSRC passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      fill_buffer(main_buffer, size);
      MPI_Send(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
      MPI_Recv(main_buffer, size, MPI_CHAR, MPI_ANY_SOURCE, MPI_ANY_TAG,
               MPI_COMM_WORLD, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYSRC+ANYTAG failed !\n",
                ping_side);
        goto out;
      }
    }
    fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYSRC+ANYTAG passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      fill_buffer(main_buffer, size);
      MPI_Send(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
      MPI_Recv(main_buffer, size, MPI_CHAR, rank_dst, MPI_ANY_TAG,
               MPI_COMM_WORLD, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYTAG failed !\n", ping_side);
        goto out;
      }
    }
    fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYTAG passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      fill_buffer(main_buffer, size);
      MPI_Ssend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
      MPI_Recv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
               MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Ssend/MPI_Recv failed !\n", ping_side);
        goto out;
      }

    }
    fprintf(stderr, "[%d] MPI_Ssend/MPI_Recv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      fill_buffer(main_buffer, size);
      MPI_Rsend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
      MPI_Recv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
               MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Rsend/MPI_Recv failed !\n", ping_side);
        goto out;
      }

    }
    fprintf(stderr, "[%d] MPI_Rsend/MPI_Recv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    /* non blocking functions */
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      fill_buffer(main_buffer, size);
      MPI_Isend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      compute(100);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      zero_buffer(main_buffer, size);
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Isend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }
    }
    fprintf(stderr, "[%d] MPI_Isend/MPI_Irecv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      fill_buffer(main_buffer, size);
      MPI_Issend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
                 &req);
      compute(100);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      zero_buffer(main_buffer, size);
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Issend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }
    }
    fprintf(stderr, "[%d] MPI_Issend/MPI_Irecv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      fill_buffer(main_buffer, size);
      MPI_Irsend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
                 &req);
      compute(100);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      zero_buffer(main_buffer, size);
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Irsend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }
    }
    fprintf(stderr, "[%d] MPI_Irsend/MPI_Irecv passed\n", ping_side);
    MPI_Barrier(MPI_COMM_WORLD);

    /* MPI_Bsend */
    int bufsize = 1024 + MPI_BSEND_OVERHEAD;
    char *buf = malloc(bufsize);
    MPI_Buffer_attach(buf, bufsize);

    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      fill_buffer(main_buffer, size);
      MPI_Bsend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Irsend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }
    }
    fprintf(stderr, "[%d] MPI_Bsend/MPI_Irecv passed\n", ping_side);
    MPI_Barrier(MPI_COMM_WORLD);

    /* MPI_Ibsend */
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      fill_buffer(main_buffer, size);
      MPI_Bsend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      compute(100);
      zero_buffer(main_buffer, size);
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Irsend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }
    }
    MPI_Buffer_detach(&buf, &bufsize);
    fprintf(stderr, "[%d] MPI_Ibsend/MPI_Irecv passed\n", ping_side);
    MPI_Barrier(MPI_COMM_WORLD);

    /* MPI_Waitall */
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req[4];
      int vars[4];
      int i;
      for (i = 0; i < 4; i++) {
        vars[i] = i * i;
        MPI_Isend(&vars[i], 1, MPI_INTEGER, rank_dst, 0, MPI_COMM_WORLD,
                  &req[i]);
      }
      MPI_Waitall(4, req, MPI_STATUS_IGNORE);
      compute(100);

      for (i = 0; i < 4; i++) {
        vars[i] = -1;
        MPI_Irecv(&vars[i], 1, MPI_INTEGER, rank_dst, 0, MPI_COMM_WORLD,
                  &req[i]);
      }
      MPI_Waitall(4, req, MPI_STATUS_IGNORE);

      for (i = 0; i < 4; i++) {
        if (vars[i] != i * i) {
          fprintf(stderr, "[%d] MPI_Waitall failed !\n", ping_side);
          goto out;
        }
      }
    }
    fprintf(stderr, "[%d] MPI_Waitall passed\n", ping_side);
    MPI_Barrier(MPI_COMM_WORLD);

  } else {
    int size = start_len;
    int nb_samples;

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Recv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
               MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Send/MPI_Recv failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Send(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Send/MPI_Recv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Recv(main_buffer, size, MPI_CHAR, MPI_ANY_SOURCE, 0, MPI_COMM_WORLD,
               MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYSRC failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Send(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYSRC passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Recv(main_buffer, size, MPI_CHAR, MPI_ANY_SOURCE, MPI_ANY_TAG,
               MPI_COMM_WORLD, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYSRC+ANYTAG failed !\n",
                ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Send(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYSRC+ANYTAG passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Recv(main_buffer, size, MPI_CHAR, rank_dst, MPI_ANY_TAG,
               MPI_COMM_WORLD, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYTAG failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Send(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Send/MPI_Recv ANYTAG passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Recv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
               MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Ssend/MPI_Recv failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Ssend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Ssend/MPI_Recv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Recv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
               MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Rsend/MPI_Recv failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Rsend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Rsend/MPI_Recv passed\n", ping_side);

    /* non blocking functions */
    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Isend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Isend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Isend/MPI_Irecv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Isend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Issend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
                 &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Issend/MPI_Irecv passed\n", ping_side);

    MPI_Barrier(MPI_COMM_WORLD);
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Irsend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Irsend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
                 &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Irsend/MPI_Irecv passed\n", ping_side);
    MPI_Barrier(MPI_COMM_WORLD);

    /* MPI_Bsend */
    int bufsize = 1024 + MPI_BSEND_OVERHEAD;
    char *buf = malloc(bufsize);
    MPI_Buffer_attach(buf, bufsize);

    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Irsend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Bsend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD);
      zero_buffer(main_buffer, size);
    }
    fprintf(stderr, "[%d] MPI_Bsend/MPI_Irecv passed\n", ping_side);
    MPI_Barrier(MPI_COMM_WORLD);

    /* MPI_Ibsend */
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req;
      MPI_Irecv(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD, &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      if (check_buffer(main_buffer, size)) {
        fprintf(stderr, "[%d] MPI_Irsend/MPI_Irecv failed !\n", ping_side);
        goto out;
      }

      fill_buffer(main_buffer, size);
      MPI_Ibsend(main_buffer, size, MPI_CHAR, rank_dst, 0, MPI_COMM_WORLD,
                 &req);
      MPI_Wait(&req, MPI_STATUS_IGNORE);
      zero_buffer(main_buffer, size);
    }
    MPI_Buffer_detach(&buf, &bufsize);
    fprintf(stderr, "[%d] MPI_Ibsend/MPI_Irecv passed\n", ping_side);
    MPI_Barrier(MPI_COMM_WORLD);

    /* MPI_Ibsend */
    for (nb_samples = 0; nb_samples < iterations; nb_samples++) {
      MPI_Request req[4];
      int vars[4];
      int i;
      for (i = 0; i < 4; i++) {
        vars[i] = -1;
        MPI_Irecv(&vars[i], 1, MPI_INTEGER, rank_dst, 0, MPI_COMM_WORLD,
                  &req[i]);
      }
      MPI_Waitall(4, req, MPI_STATUS_IGNORE);
      compute(100);

      for (i = 0; i < 4; i++) {
        MPI_Isend(&vars[i], 1, MPI_INTEGER, rank_dst, 0, MPI_COMM_WORLD,
                  &req[i]);
      }

      MPI_Waitall(4, req, MPI_STATUS_IGNORE);

      for (i = 0; i < 4; i++) {
        if (vars[i] != i * i) {
          fprintf(stderr, "[%d] MPI_Waitall failed !\n", ping_side);
          goto out;
        }
      }
    }
    fprintf(stderr, "[%d] MPI_Waitall passed\n", ping_side);
    MPI_Barrier(MPI_COMM_WORLD);
  }
  free(main_buffer);
  out: MPI_Finalize();

  return 0;
}
