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libs/ck-libs/ampi/romio/adio/common/get_fp_posn.c

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

#include "adio.h"
#include "adio_extern.h"
#include "adioi.h"

/* returns the current position of the individual file pointer
   in etype units relative to the current view. */

void ADIOI_Get_position(ADIO_File fd, ADIO_Offset *offset)
{
    ADIOI_Flatlist_node *flat_file;
    int i, flag;
    unsigned filetype_size;
    int etype_size, filetype_is_contig;
    MPI_Aint filetype_extent;
    ADIO_Offset disp, byte_offset, sum=0, size_in_file, n_filetypes, frd_size;
    
    ADIOI_Datatype_iscontig(fd->filetype, &filetype_is_contig);
    etype_size = fd->etype_size;

    if (filetype_is_contig) *offset = (fd->fp_ind - fd->disp)/etype_size;
    else {
/* filetype already flattened in ADIO_Open */
        flat_file = CtvAccess(ADIOI_Flatlist);
        while (flat_file->type != fd->filetype) flat_file = flat_file->next;

    MPI_Type_size(fd->filetype, (int*)&filetype_size);
    MPI_Type_extent(fd->filetype, &filetype_extent);

    disp = fd->disp;
    byte_offset = fd->fp_ind;
    n_filetypes = -1;
    flag = 0;
    while (!flag) {
        sum = 0;
        n_filetypes++;
        for (i=0; i<flat_file->count; i++) {
        sum += flat_file->blocklens[i];
        if (disp + flat_file->indices[i] + 
                n_filetypes* ADIOI_AINT_CAST_TO_OFFSET filetype_extent + flat_file->blocklens[i] 
            >= byte_offset) {
            frd_size = disp + flat_file->indices[i] + 
            n_filetypes * ADIOI_AINT_CAST_TO_OFFSET filetype_extent
            + flat_file->blocklens[i] - byte_offset;
            sum -= frd_size;
            flag = 1;
            break;
        }
        }
    }
    size_in_file = n_filetypes * (ADIO_Offset)filetype_size + sum;
    *offset = size_in_file/etype_size;
    }
}

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