/*
 * Copyright (C) by Argonne National Laboratory
 *     See COPYRIGHT in top-level directory
 */

#include "mpi.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/* tests whether atomicity semantics are satisfied for overlapping accesses
   in atomic mode. The probability of detecting errors is higher if you run
   it on 8 or more processes. */

/* The file name is taken as a command-line argument. */

static void handle_error(int errcode, const char *str)
{
    char msg[MPI_MAX_ERROR_STRING];
    int resultlen;
    MPI_Error_string(errcode, msg, &resultlen);
    fprintf(stderr, "%s: %s\n", str, msg);
    MPI_Abort(MPI_COMM_WORLD, 1);
}

#define MPI_CHECK(fn) { int errcode; errcode = (fn); if (errcode != MPI_SUCCESS) handle_error(errcode, #fn); }


#define BUFSIZE 10000   /* no. of integers */
#define VERBOSE 0
int main(int argc, char **argv)
{
    int *writebuf, *readbuf, i, mynod, nprocs, len, err;
    char *filename;
    int errs = 0, toterrs;
    MPI_Datatype newtype;
    MPI_File fh;
    MPI_Status status;
    MPI_Info info;

    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &mynod);
    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);

/* process 0 takes the file name as a command-line argument and
   broadcasts it to other processes */
    if (!mynod) {
        i = 1;
        while ((i < argc) && strcmp("-fname", *argv)) {
            i++;
            argv++;
        }
        if (i >= argc) {
            fprintf(stderr, "\n*#  Usage: coll_test -fname filename\n\n");
            MPI_Abort(MPI_COMM_WORLD, 1);
        }
        argv++;
        len = strlen(*argv);
        filename = (char *) malloc(len + 1);
        strcpy(filename, *argv);
        MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);
        MPI_Bcast(filename, len + 1, MPI_CHAR, 0, MPI_COMM_WORLD);
    } else {
        MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);
        filename = (char *) malloc(len + 1);
        MPI_Bcast(filename, len + 1, MPI_CHAR, 0, MPI_COMM_WORLD);
    }

    writebuf = (int *) malloc(BUFSIZE * sizeof(int));
    readbuf = (int *) malloc(BUFSIZE * sizeof(int));

/* test atomicity of contiguous accesses */

/* initialize file to all zeros */
    if (!mynod) {
        /* ignore error: file may or may not exist */
        MPI_File_delete(filename, MPI_INFO_NULL);
        MPI_CHECK(MPI_File_open(MPI_COMM_SELF, filename,
                                MPI_MODE_CREATE | MPI_MODE_RDWR, MPI_INFO_NULL, &fh));
        for (i = 0; i < BUFSIZE; i++)
            writebuf[i] = 0;
        MPI_CHECK(MPI_File_write(fh, writebuf, BUFSIZE, MPI_INT, &status));
        MPI_CHECK(MPI_File_close(&fh));
#if VERBOSE
        fprintf(stderr, "\ntesting contiguous accesses\n");
#endif
    }
    MPI_Barrier(MPI_COMM_WORLD);

    for (i = 0; i < BUFSIZE; i++)
        writebuf[i] = 10;
    for (i = 0; i < BUFSIZE; i++)
        readbuf[i] = 20;

    MPI_CHECK(MPI_File_open(MPI_COMM_WORLD, filename,
                            MPI_MODE_CREATE | MPI_MODE_RDWR, MPI_INFO_NULL, &fh));

/* set atomicity to true */
    err = MPI_File_set_atomicity(fh, 1);
    if (err != MPI_SUCCESS) {
        fprintf(stderr, "Atomic mode not supported on this file system.\n");
        fflush(stderr);
        errs++;
        goto fn_exit;
    }

    MPI_Barrier(MPI_COMM_WORLD);

/* process 0 writes and others concurrently read. In atomic mode,
   the data read must be either all old values or all new values; nothing
   in between. */

    if (!mynod) {
        MPI_CHECK(MPI_File_write(fh, writebuf, BUFSIZE, MPI_INT, &status));
    } else {
        err = MPI_File_read(fh, readbuf, BUFSIZE, MPI_INT, &status);
        if (err == MPI_SUCCESS) {
            if (readbuf[0] == 0) {      /* the rest must also be 0 */
                for (i = 1; i < BUFSIZE; i++)
                    if (readbuf[i] != 0) {
                        errs++;
                        fprintf(stderr, "Process %d: readbuf[%d] is %d, should be 0\n", mynod, i,
                                readbuf[i]);
                        goto fn_exit;
                    }
            } else if (readbuf[0] == 10) {      /* the rest must also be 10 */
                for (i = 1; i < BUFSIZE; i++)
                    if (readbuf[i] != 10) {
                        errs++;
                        fprintf(stderr, "Process %d: readbuf[%d] is %d, should be 10\n", mynod, i,
                                readbuf[i]);
                        goto fn_exit;
                    }
            } else {
                errs++;
                fprintf(stderr, "Process %d: readbuf[0] is %d, should be either 0 or 10\n", mynod,
                        readbuf[0]);
            }
        }
    }

    MPI_CHECK(MPI_File_close(&fh));

    MPI_Barrier(MPI_COMM_WORLD);


/* repeat the same test with a noncontiguous filetype */

    MPI_Type_vector(BUFSIZE, 1, 2, MPI_INT, &newtype);
    MPI_Type_commit(&newtype);

    MPI_Info_create(&info);
    /* I am setting these info values for testing purposes only. It is
     * better to use the default values in practice. */
    MPI_Info_set(info, "ind_rd_buffer_size", "1209");
    MPI_Info_set(info, "ind_wr_buffer_size", "1107");

    if (!mynod) {
        MPI_CHECK(MPI_File_delete(filename, MPI_INFO_NULL));
        MPI_CHECK(MPI_File_open(MPI_COMM_SELF, filename,
                                MPI_MODE_CREATE | MPI_MODE_RDWR, info, &fh));
        for (i = 0; i < BUFSIZE; i++)
            writebuf[i] = 0;
        MPI_CHECK(MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", info));
        MPI_CHECK(MPI_File_write(fh, writebuf, BUFSIZE, MPI_INT, &status));
        MPI_File_close(&fh);
#if VERBOSE
        fprintf(stderr, "\ntesting noncontiguous accesses\n");
#endif
    }
    MPI_Barrier(MPI_COMM_WORLD);

    for (i = 0; i < BUFSIZE; i++)
        writebuf[i] = 10;
    for (i = 0; i < BUFSIZE; i++)
        readbuf[i] = 20;

    MPI_CHECK(MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE | MPI_MODE_RDWR, info, &fh));
    MPI_CHECK(MPI_File_set_atomicity(fh, 1));
    MPI_CHECK(MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", info));
    MPI_Barrier(MPI_COMM_WORLD);

    if (!mynod) {
        MPI_CHECK(MPI_File_write(fh, writebuf, BUFSIZE, MPI_INT, &status));
    } else {
        err = MPI_File_read(fh, readbuf, BUFSIZE, MPI_INT, &status);
        if (err == MPI_SUCCESS) {
            if (readbuf[0] == 0) {
                for (i = 1; i < BUFSIZE; i++)
                    if (readbuf[i] != 0) {
                        errs++;
                        fprintf(stderr, "Process %d: readbuf[%d] is %d, should be 0\n", mynod, i,
                                readbuf[i]);
                        goto fn_exit;
                    }
            } else if (readbuf[0] == 10) {
                for (i = 1; i < BUFSIZE; i++)
                    if (readbuf[i] != 10) {
                        errs++;
                        fprintf(stderr, "Process %d: readbuf[%d] is %d, should be 10\n", mynod, i,
                                readbuf[i]);
                        goto fn_exit;
                    }
            } else {
                errs++;
                fprintf(stderr, "Process %d: readbuf[0] is %d, should be either 0 or 10\n", mynod,
                        readbuf[0]);
            }
        }
    }

    MPI_Type_free(&newtype);
    MPI_Info_free(&info);
  fn_exit:
    MPI_File_close(&fh);

    MPI_Barrier(MPI_COMM_WORLD);

    MPI_Allreduce(&errs, &toterrs, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
    if (mynod == 0) {
        if (toterrs > 0) {
            fprintf(stderr, "Found %d errors\n", toterrs);
        } else {
            fprintf(stdout, " No Errors\n");
        }
    }
    free(writebuf);
    free(readbuf);
    free(filename);

    MPI_Finalize();
    return 0;
}