From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001
From: Joseph Hunkeler <jhunkeler@gmail.com>
Date: Wed, 8 Jul 2015 20:46:52 -0400
Subject: Initial commit

---
 sys/fmio/fmiosbuf.x | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 sys/fmio/fmiosbuf.x

(limited to 'sys/fmio/fmiosbuf.x')

diff --git a/sys/fmio/fmiosbuf.x b/sys/fmio/fmiosbuf.x
new file mode 100644
index 00000000..358d4136
--- /dev/null
+++ b/sys/fmio/fmiosbuf.x
@@ -0,0 +1,56 @@
+# 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
-- 
cgit