/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 *
 *  (C) 2003 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include "mpitest.h"

/*
static char MTEST_Descrip[] = "Test set_view with DISPLACEMENT_CURRENT";
*/

int main(int argc, char *argv[])
{
    int errs = 0, err;
    int size, rank, *buf;
    MPI_Offset offset;
    MPI_File fh;
    MPI_Comm comm;
    MPI_Status status;

    MTest_Init(&argc, &argv);

    /* This test reads a header then sets the view to every "size" int,
     * using set view and current displacement.  The file is first written
     * using a combination of collective and ordered writes */

    comm = MPI_COMM_WORLD;
    err = MPI_File_open(comm, (char *) "test.ord",
                        MPI_MODE_WRONLY | MPI_MODE_CREATE, MPI_INFO_NULL, &fh);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Open(1)", err);
    }
    MPI_Comm_size(comm, &size);
    MPI_Comm_rank(comm, &rank);
    buf = (int *) malloc(size * sizeof(int));
    buf[0] = size;
    err = MPI_File_write_all(fh, buf, 1, MPI_INT, &status);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Write_all", err);
    }
    err = MPI_File_get_position(fh, &offset);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Get_position", err);
    }
    err = MPI_File_seek_shared(fh, offset, MPI_SEEK_SET);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Seek_shared", err);
    }
    buf[0] = rank;
    err = MPI_File_write_ordered(fh, buf, 1, MPI_INT, &status);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Write_ordered", err);
    }
    err = MPI_File_close(&fh);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Close(1)", err);
    }

    /* Reopen the file as sequential */
    err = MPI_File_open(comm, (char *) "test.ord",
                        MPI_MODE_RDONLY | MPI_MODE_SEQUENTIAL |
                        MPI_MODE_DELETE_ON_CLOSE, MPI_INFO_NULL, &fh);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Open(Read)", err);
    }

    if (rank == 0) {
        err = MPI_File_read_shared(fh, buf, 1, MPI_INT, &status);
        if (err) {
            errs++;
            MTestPrintErrorMsg("Read_all", err);
        }
        if (buf[0] != size) {
            errs++;
            fprintf(stderr, "Unexpected value for the header = %d, should be %d\n", buf[0], size);
            fflush(stderr);
        }
    }
    MPI_Barrier(comm);
    /* All processes must provide the same file view for MODE_SEQUENTIAL */
    /* See MPI 2.1, 13.3 - DISPLACEMENT_CURRENT is *required* for
     * MODE_SEQUENTIAL files */
    err = MPI_File_set_view(fh, MPI_DISPLACEMENT_CURRENT, MPI_INT,
                            MPI_INT, (char *) "native", MPI_INFO_NULL);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Set_view (DISPLACEMENT_CURRENT)", err);
    }
    buf[0] = -1;
    err = MPI_File_read_ordered(fh, buf, 1, MPI_INT, &status);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Read_all", err);
    }
    if (buf[0] != rank) {
        errs++;
        fprintf(stderr, "%d: buf[0] = %d\n", rank, buf[0]);
        fflush(stderr);
    }

    free(buf);
    err = MPI_File_close(&fh);
    if (err) {
        errs++;
        MTestPrintErrorMsg("Close(2)", err);
    }

    MTest_Finalize(errs);
    MPI_Finalize();
    return 0;
}