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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <config.h>
include <fio.h>
include "fmio.h"
# FMIO_SETBUF -- Set the various buffer size parameters, making sure that the
# physical constraints are met, i.e., that the buffers are an integral
# multiple of the device block size, and do not exceed the maximum transfer
# size for the device.
procedure fmio_setbuf (fm)
pointer fm #I FMIO descriptor
int devblksize, devmaxsize
int optbufsize, maxbufsize, szbpage
begin
# Get the device parameters for the device on which datafile resides.
call zsttbf (FM_CHAN(fm), FSTT_BLKSIZE, devblksize)
call zsttbf (FM_CHAN(fm), FSTT_MAXBUFSIZE, devmaxsize)
# Make sure the page size is an integral multiple of the block size.
szbpage = (FM_SZBPAGE(fm) + devblksize-1) / devblksize * devblksize
# Set the optimum (default) file buffer size.
optbufsize = FM_OPTBUFSIZE(fm)
if (optbufsize <= 0) {
if (DEF_OPTBUFNP <= 0)
call zsttbf (FM_CHAN(fm), FSTT_OPTBUFSIZE, optbufsize)
else
optbufsize = DEF_OPTBUFNP * szbpage
}
# Set the maximum file buffer size.
maxbufsize = FM_MAXBUFSIZE(fm)
if (maxbufsize <= 0) {
if (DEF_MAXBUFNP > 0)
maxbufsize = DEF_MAXBUFNP * szbpage
else
maxbufsize = devmaxsize
}
# Apply constraints and store values.
if (devmaxsize > 0)
maxbufsize = min (maxbufsize, devmaxsize)
if (maxbufsize > 0)
FM_MAXBUFSIZE(fm) = max (szbpage, maxbufsize / szbpage * szbpage)
FM_OPTBUFSIZE(fm) = max (szbpage, optbufsize / szbpage * szbpage)
FM_DEVBLKSIZE(fm) = devblksize
FM_SZBPAGE(fm) = szbpage
FM_DHMODIFIED(fm) = YES
end
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