/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 *   Copyright (C) 1997 University of Chicago.
 *   See COPYRIGHT notice in top-level directory.
 */

#include "mpioimpl.h"

#ifdef HAVE_WEAK_SYMBOLS

#if defined(HAVE_PRAGMA_WEAK)
#pragma weak MPI_File_seek_shared = PMPI_File_seek_shared
#elif defined(HAVE_PRAGMA_HP_SEC_DEF)
#pragma _HP_SECONDARY_DEF PMPI_File_seek_shared MPI_File_seek_shared
#elif defined(HAVE_PRAGMA_CRI_DUP)
#pragma _CRI duplicate MPI_File_seek_shared as PMPI_File_seek_shared
/* end of weak pragmas */
#elif defined(HAVE_WEAK_ATTRIBUTE)
int MPI_File_seek_shared(MPI_File fh, MPI_Offset offset, int whence)
    __attribute__ ((weak, alias("PMPI_File_seek_shared")));
#endif

/* Include mapping from MPI->PMPI */
#define MPIO_BUILD_PROFILING
#include "mpioprof.h"
#endif

/*@
    MPI_File_seek_shared - Updates the shared file pointer

Input Parameters:
. fh - file handle (handle)
. offset - file offset (integer)
. whence - update mode (state)

.N fortran
@*/
int MPI_File_seek_shared(MPI_File fh, MPI_Offset offset, int whence)
{
    int error_code = MPI_SUCCESS, tmp_whence, myrank;
    static char myname[] = "MPI_FILE_SEEK_SHARED";
    MPI_Offset curr_offset, eof_offset, tmp_offset;
    ADIO_File adio_fh;

    ROMIO_THREAD_CS_ENTER();

    adio_fh = MPIO_File_resolve(fh);

    /* --BEGIN ERROR HANDLING-- */
    MPIO_CHECK_FILE_HANDLE(adio_fh, myname, error_code);
    MPIO_CHECK_NOT_SEQUENTIAL_MODE(adio_fh, myname, error_code);
    MPIO_CHECK_FS_SUPPORTS_SHARED(adio_fh, myname, error_code);
    /* --END ERROR HANDLING-- */

    tmp_offset = offset;
    MPI_Bcast(&tmp_offset, 1, ADIO_OFFSET, 0, adio_fh->comm);
    /* --BEGIN ERROR HANDLING-- */
    if (tmp_offset != offset) {
        error_code = MPIO_Err_create_code(MPI_SUCCESS, MPIR_ERR_RECOVERABLE,
                                          myname, __LINE__, MPI_ERR_ARG, "**notsame", 0);
        error_code = MPIO_Err_return_file(adio_fh, error_code);
        goto fn_exit;
    }
    /* --END ERROR HANDLING-- */

    tmp_whence = whence;
    MPI_Bcast(&tmp_whence, 1, MPI_INT, 0, adio_fh->comm);
    /* --BEGIN ERROR HANDLING-- */
    if (tmp_whence != whence) {
        error_code = MPIO_Err_create_code(MPI_SUCCESS, MPIR_ERR_RECOVERABLE,
                                          myname, __LINE__, MPI_ERR_ARG, "**iobadwhence", 0);
        error_code = MPIO_Err_return_file(adio_fh, error_code);
        goto fn_exit;
    }
    /* --END ERROR HANDLING-- */

    ADIOI_TEST_DEFERRED(adio_fh, "MPI_File_seek_shared", &error_code);

    MPI_Comm_rank(adio_fh->comm, &myrank);

    if (!myrank) {
        switch (whence) {
            case MPI_SEEK_SET:
                /* --BEGIN ERROR HANDLING-- */
                if (offset < 0) {
                    error_code = MPIO_Err_create_code(MPI_SUCCESS,
                                                      MPIR_ERR_RECOVERABLE,
                                                      myname, __LINE__,
                                                      MPI_ERR_ARG, "**iobadoffset", 0);
                    error_code = MPIO_Err_return_file(adio_fh, error_code);
                    goto fn_exit;
                }
                /* --END ERROR HANDLING-- */
                break;
            case MPI_SEEK_CUR:
                /* get current location of shared file pointer */
                ADIO_Get_shared_fp(adio_fh, 0, &curr_offset, &error_code);
                /* --BEGIN ERROR HANDLING-- */
                if (error_code != MPI_SUCCESS) {
                    error_code = MPIO_Err_create_code(MPI_SUCCESS,
                                                      MPIR_ERR_FATAL,
                                                      myname, __LINE__,
                                                      MPI_ERR_INTERN, "**iosharedfailed", 0);
                    error_code = MPIO_Err_return_file(adio_fh, error_code);
                    goto fn_exit;
                }
                /* --END ERROR HANDLING-- */
                offset += curr_offset;
                /* --BEGIN ERROR HANDLING-- */
                if (offset < 0) {
                    error_code = MPIO_Err_create_code(MPI_SUCCESS,
                                                      MPIR_ERR_RECOVERABLE,
                                                      myname, __LINE__,
                                                      MPI_ERR_ARG, "**ionegoffset", 0);
                    error_code = MPIO_Err_return_file(adio_fh, error_code);
                    goto fn_exit;
                }
                /* --END ERROR HANDLING-- */
                break;
            case MPI_SEEK_END:
                /* find offset corr. to end of file */
                ADIOI_Get_eof_offset(adio_fh, &eof_offset);
                offset += eof_offset;
                /* --BEGIN ERROR HANDLING-- */
                if (offset < 0) {
                    error_code = MPIO_Err_create_code(MPI_SUCCESS,
                                                      MPIR_ERR_RECOVERABLE,
                                                      myname, __LINE__,
                                                      MPI_ERR_ARG, "**ionegoffset", 0);
                    error_code = MPIO_Err_return_file(adio_fh, error_code);
                    goto fn_exit;
                }
                /* --END ERROR HANDLING-- */
                break;
            default:
                /* --BEGIN ERROR HANDLING-- */
                error_code = MPIO_Err_create_code(MPI_SUCCESS,
                                                  MPIR_ERR_RECOVERABLE,
                                                  myname, __LINE__, MPI_ERR_ARG,
                                                  "**iobadwhence", 0);
                error_code = MPIO_Err_return_file(adio_fh, error_code);
                goto fn_exit;
                /* --END ERROR HANDLING-- */
        }

        ADIO_Set_shared_fp(adio_fh, offset, &error_code);
        /* --BEGIN ERROR HANDLING-- */
        if (error_code != MPI_SUCCESS) {
            error_code = MPIO_Err_create_code(MPI_SUCCESS,
                                              MPIR_ERR_FATAL,
                                              myname, __LINE__,
                                              MPI_ERR_INTERN, "**iosharedfailed", 0);
            error_code = MPIO_Err_return_file(adio_fh, error_code);
            goto fn_exit;
        }
        /* --END ERROR HANDLING-- */

    }

    /* FIXME: explain why the barrier is necessary */
    MPI_Barrier(adio_fh->comm);

    error_code = MPI_SUCCESS;

  fn_exit:
    ROMIO_THREAD_CS_EXIT();

    return error_code;
}