/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
 * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer:  rky 980813
 *
 * Purpose:	Functions to read/write directly between app buffer and file.
 *
 * 		Beware of the ifdef'ed print statements.
 *		I didn't make them portable.
 */

/****************/
/* Module Setup */
/****************/

#define H5D_PACKAGE		/*suppress error about including H5Dpkg	  */


/***********/
/* Headers */
/***********/
#include "H5private.h"		/* Generic Functions			*/
#include "H5Dpkg.h"		/* Datasets				*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Fprivate.h"		/* File access				*/
#include "H5FDprivate.h"	/* File drivers				*/
#include "H5Oprivate.h"		/* Object headers		  	*/
#include "H5Pprivate.h"         /* Property lists                       */
#include "H5Sprivate.h"		/* Dataspaces 				*/

#ifdef H5_HAVE_PARALLEL

/****************/
/* Local Macros */
/****************/

/******************/
/* Local Typedefs */
/******************/

/********************/
/* Local Prototypes */
/********************/

/* For regular hyperslab selection. */
static herr_t
H5D_mpio_spaces_xfer(H5D_io_info_t *io_info, size_t elmt_size,
                     const H5S_t *file_space, const H5S_t *mem_space,
                     void *buf/*out*/,
		     hbool_t do_write);

/*********************/
/* Package Variables */
/*********************/

/*******************/
/* Local Variables */
/*******************/


/*-------------------------------------------------------------------------
 * Function:	H5D_mpio_opt_possible
 *
 * Purpose:	Checks if an direct I/O transfer is possible between memory and
 *                  the file.
 *
 * Return:	Success:        Non-negative: TRUE or FALSE
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              Wednesday, April 3, 2002
 *
 *-------------------------------------------------------------------------
 */
htri_t
H5D_mpio_opt_possible( const H5D_io_info_t *io_info,
    const H5S_t *mem_space, const H5S_t *file_space, const H5T_path_t *tpath)
{
    int         local_opinion = TRUE;   /* This process's idea of whether to perform collective I/O or not */
    int         consensus;              /* Consensus opinion of all processes */
    int         mpi_code;               /* MPI error code */
    htri_t ret_value=TRUE;

    FUNC_ENTER_NOAPI(H5D_mpio_opt_possible, FAIL);

    /* Check args */
    assert(io_info);
    assert(mem_space);
    assert(file_space);

    /* For independent I/O, get out quickly and don't try to form consensus */
    if (io_info->dxpl_cache->xfer_mode==H5FD_MPIO_INDEPENDENT)
        HGOTO_DONE(FALSE);

    /* Optimized MPI types flag must be set and it is must be collective IO */
    /* (Don't allow parallel I/O for the MPI-posix driver, since it doesn't do real collective I/O) */
    if (!(H5S_mpi_opt_types_g && io_info->dxpl_cache->xfer_mode==H5FD_MPIO_COLLECTIVE && !IS_H5FD_MPIPOSIX(io_info->dset->oloc.file))) {
        local_opinion = FALSE;
        goto broadcast;
    } /* end if */

    /* Check whether these are both simple or scalar dataspaces */
    if (!((H5S_SIMPLE==H5S_GET_EXTENT_TYPE(mem_space) || H5S_SCALAR==H5S_GET_EXTENT_TYPE(mem_space))
            && (H5S_SIMPLE==H5S_GET_EXTENT_TYPE(file_space) || H5S_SCALAR==H5S_GET_EXTENT_TYPE(file_space)))) {
        local_opinion = FALSE;
        goto broadcast;
    } /* end if */

    /* Can't currently handle point selections */
    if (H5S_SEL_POINTS==H5S_GET_SELECT_TYPE(mem_space) || H5S_SEL_POINTS==H5S_GET_SELECT_TYPE(file_space)) {
        local_opinion = FALSE;
        goto broadcast;
    } /* end if */

    /* Dataset storage must be contiguous or chunked */
    if (!(io_info->dset->shared->layout.type == H5D_CONTIGUOUS ||
            io_info->dset->shared->layout.type == H5D_CHUNKED)) {
        local_opinion = FALSE;
        goto broadcast;
    } /* end if */

    /*The handling of memory space is different for chunking
	  and contiguous storage,
	  For contigous storage, mem_space and file_space won't
	  change when it it is doing disk IO.
	  For chunking storage, mem_space will change for different
	  chunks. So for chunking storage, whether we can use
	  collective IO will defer until the each chunk IO is reached.
	  For contiguous storage, if we find the MPI-IO cannot
	  support complicated MPI derived data type, we will
	  set use_par_opt_io = FALSE.
	*/
#ifndef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
    if(io_info->dset->shared->layout.type == H5D_CONTIGUOUS)
        if((H5S_SELECT_IS_REGULAR(file_space) != TRUE) ||
                (H5S_SELECT_IS_REGULAR(mem_space) != TRUE)) {
            local_opinion = FALSE;
            goto broadcast;
        } /* end if */
#endif

    /* Don't allow collective operations if filters need to be applied */
    if(io_info->dset->shared->layout.type == H5D_CHUNKED)
        if(io_info->dset->shared->dcpl_cache.pline.nused>0) {
            local_opinion = FALSE;
            goto broadcast;
        } /* end if */

    /* Don't allow collective operations if datatype conversions need to happen */
    if(!H5T_path_noop(tpath)) {
        local_opinion = FALSE;
        goto broadcast;
    } /* end if */

    /* Don't allow collective operations if data transform operations should occur */
    if(!H5Z_xform_noop(io_info->dxpl_cache->data_xform_prop)) {
        local_opinion = FALSE;
        goto broadcast;
    } /* end if */

broadcast:
    /* Form consensus opinion among all processes about whether to perform
     * collective I/O */
    if (MPI_SUCCESS != (mpi_code = MPI_Allreduce(&local_opinion, &consensus, 1, MPI_INT, MPI_LAND, io_info->comm)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Allreduce failed", mpi_code)

    ret_value = consensus > 0 ? TRUE : FALSE;

done:
    FUNC_LEAVE_NOAPI(ret_value);
} /* H5D_mpio_opt_possible() */


/*-------------------------------------------------------------------------
 * Function:	H5D_mpio_spaces_xfer
 *
 * Purpose:	Use MPI-IO to transfer data efficiently
 *		directly between app buffer and file.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Programmer:	rky 980813
 *
 * Notes:
 *      For collective data transfer only since this would eventually call
 *      H5FD_mpio_setup to do setup to eveually call MPI_File_set_view in
 *      H5FD_mpio_read or H5FD_mpio_write.  MPI_File_set_view is a collective
 *      call.  Letting independent data transfer use this route would result in
 *      hanging.
 *
 *      The preconditions for calling this routine are located in the
 *      H5S_mpio_opt_possible() routine, which determines whether this routine
 *      can be called for a given dataset transfer.
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D_mpio_spaces_xfer(H5D_io_info_t *io_info, size_t elmt_size,
    const H5S_t *file_space, const H5S_t *mem_space,
    void *_buf /*out*/, hbool_t do_write )
{
    haddr_t	 addr;                  /* Address of dataset (or selection) within file */
    size_t	 mpi_buf_count, mpi_file_count;       /* Number of "objects" to transfer */
    hsize_t	 mpi_buf_offset, mpi_file_offset;       /* Offset within dataset where selection (ie. MPI type) begins */
    MPI_Datatype mpi_buf_type, mpi_file_type;   /* MPI types for buffer (memory) and file */
    hbool_t	 mbt_is_derived=0,      /* Whether the buffer (memory) type is derived and needs to be free'd */
		 mft_is_derived=0;      /* Whether the file type is derived and needs to be free'd */
    hbool_t	 plist_is_setup=0;      /* Whether the dxpl has been customized */
    uint8_t	*buf=(uint8_t *)_buf;   /* Alias for pointer arithmetic */
    int          mpi_code;              /* MPI return code */
    herr_t	 ret_value = SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5D_mpio_spaces_xfer);

    /* Check args */
    assert (io_info);
    assert (io_info->dset);
    assert (file_space);
    assert (mem_space);
    assert (buf);
    assert (IS_H5FD_MPIO(io_info->dset->oloc.file));
    /* Make certain we have the correct type of property list */
    assert(TRUE==H5P_isa_class(io_info->dxpl_id,H5P_DATASET_XFER));

    /* create the MPI buffer type */
    if (H5S_mpio_space_type( mem_space, elmt_size,
			       /* out: */
			       &mpi_buf_type,
			       &mpi_buf_count,
			       &mpi_buf_offset,
			       &mbt_is_derived )<0)
    	HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL,"couldn't create MPI buf type");

    /* create the MPI file type */
    if ( H5S_mpio_space_type( file_space, elmt_size,
			       /* out: */
			       &mpi_file_type,
			       &mpi_file_count,
			       &mpi_file_offset,
			       &mft_is_derived )<0)
    	HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL,"couldn't create MPI file type");

    /* Get the base address of the contiguous dataset or the chunk */
    if(io_info->dset->shared->layout.type == H5D_CONTIGUOUS)
       addr = H5D_contig_get_addr(io_info->dset) + mpi_file_offset;
    else {
        haddr_t   chunk_addr; /* for collective chunk IO */

        assert(io_info->dset->shared->layout.type == H5D_CHUNKED);
        chunk_addr=H5D_istore_get_addr(io_info,NULL);
        addr = H5F_BASE_ADDR(io_info->dset->oloc.file) + chunk_addr + mpi_file_offset;
    }

    /*
     * Pass buf type, file type to the file driver. Request an MPI type
     * transfer (instead of an elementary byteblock transfer).
     */
    if(H5FD_mpi_setup_collective(io_info->dxpl_id, mpi_buf_type, mpi_file_type)<0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set MPI-I/O properties");
    plist_is_setup=1;

    /* Adjust the buffer pointer to the beginning of the selection */
    buf+=mpi_buf_offset;

    /* transfer the data */
    if (do_write) {
    	if (H5F_block_write(io_info->dset->oloc.file, H5FD_MEM_DRAW, addr, mpi_buf_count, io_info->dxpl_id, buf) <0)
	    HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL,"MPI write failed");
    } else {
    	if (H5F_block_read (io_info->dset->oloc.file, H5FD_MEM_DRAW, addr, mpi_buf_count, io_info->dxpl_id, buf) <0)
	    HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL,"MPI read failed");
    }

done:
    /* Reset the dxpl settings */
    if(plist_is_setup) {
        if(H5FD_mpi_teardown_collective(io_info->dxpl_id)<0)
    	    HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "unable to reset dxpl values");
    } /* end if */

    /* free the MPI buf and file types */
    if (mbt_is_derived) {
	if (MPI_SUCCESS != (mpi_code= MPI_Type_free( &mpi_buf_type )))
            HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code);
    }
    if (mft_is_derived) {
	if (MPI_SUCCESS != (mpi_code= MPI_Type_free( &mpi_file_type )))
            HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code);
    }

    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5D_mpio_spaces_xfer() */


/*-------------------------------------------------------------------------
 * Function:	H5D_mpio_select_read
 *
 * Purpose:	MPI-IO function to read directly from app buffer to file.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Programmer:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D_mpio_select_read(H5D_io_info_t *io_info,
    size_t UNUSED nelmts, size_t elmt_size,
    const H5S_t *file_space, const H5S_t *mem_space,
    void *buf/*out*/)
{
    herr_t ret_value;

    FUNC_ENTER_NOAPI_NOFUNC(H5D_mpio_select_read);

    ret_value = H5D_mpio_spaces_xfer(io_info, elmt_size, file_space,
        mem_space, buf, 0/*read*/);

    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5D_mpio_select_read() */


/*-------------------------------------------------------------------------
 * Function:	H5D_mpio_select_write
 *
 * Purpose:	MPI-IO function to write directly from app buffer to file.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Programmer:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D_mpio_select_write(H5D_io_info_t *io_info,
    size_t UNUSED nelmts, size_t elmt_size,
    const H5S_t *file_space, const H5S_t *mem_space,
    const void *buf)
{
    herr_t ret_value;

    FUNC_ENTER_NOAPI_NOFUNC(H5D_mpio_select_write);

    /*OKAY: CAST DISCARDS CONST QUALIFIER*/
    ret_value = H5D_mpio_spaces_xfer(io_info, elmt_size, file_space,
                    mem_space, (void*)buf, 1/*write*/);

    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5D_mpio_spaces_write() */
#endif  /* H5_HAVE_PARALLEL */