1 files changed, 124 insertions, 0 deletions
diff --git a/storeio/open.c b/storeio/open.c
new file mode 100644
index 00000000..f27dc3ab
--- /dev/null
+++ b/storeio/open.c
@@ -0,0 +1,124 @@
+/* Per-open information for storeio
+
+   Copyright (C) 1995, 1996 Free Software Foundation, Inc.
+
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <hurd.h>
+#include <stdio.h>
+
+#include "open.h"
+#include "dev.h"
+
+/* Returns a new per-open structure for the device DEV in OPEN.  If an error
+   occurs, the error-code is returned, otherwise 0.  */
+error_t
+open_create (struct dev *dev, struct open **open)
+{
+  *open = malloc (sizeof (struct open));
+  if (*open == NULL)
+    return ENOMEM;
+
+  (*open)->dev = dev;
+  (*open)->offs = 0;
+  mutex_init (&(*open)->lock);
+
+  return 0;
+}
+
+/* Free OPEN and any resources it holds.  */
+void
+open_free (struct open *open)
+{
+  free (open);
+}
+
+/* Writes up to LEN bytes from BUF to OPEN's device at device offset OFFS
+   (which may be ignored if the device doesn't support random access),
+   and returns the number of bytes written in AMOUNT.  If no error occurs,
+   zero is returned, otherwise the error code is returned.  */
+error_t
+open_write (struct open *open, off_t offs, char *buf, size_t len,
+	    vm_size_t *amount)
+{
+  error_t err;
+  if (offs < 0)
+    /* Use OPEN's offset.  */
+    {
+      mutex_lock (&open->lock);
+      err = dev_write (open->dev, open->offs, buf, len, amount);
+      if (! err)
+	open->offs += *amount;
+      mutex_unlock (&open->lock);
+    }
+  else
+    err = dev_write (open->dev, offs, buf, len, amount);
+  return err;
+}    
+
+/* Reads up to AMOUNT bytes from the device into BUF and LEN using the
+   standard mach out-array convention.  If no error occurs, zero is returned,
+   otherwise the error code is returned.  */
+error_t
+open_read (struct open *open, off_t offs, size_t amount,
+	   char **buf, vm_size_t *len)
+{
+  error_t err;
+  if (offs < 0)
+    /* Use OPEN's offset.  */
+    {
+      mutex_lock (&open->lock);
+      err = dev_read (open->dev, open->offs, amount, buf, len);
+      if (! err)
+	open->offs += *len;
+      mutex_unlock (&open->lock);
+    }
+  else
+    err = dev_read (open->dev, offs, amount, buf, len);
+  return err;
+}   
+
+/* Set OPEN's location to OFFS, interpreted according to WHENCE as by seek.
+   The new absolute location is returned in NEW_OFFS (and may not be the same
+   as OFFS).  If no error occurs, zero is returned, otherwise the error code
+   is returned.  */
+error_t
+open_seek (struct open *open, off_t offs, int whence, off_t *new_offs)
+{
+  error_t err = 0;
+
+  mutex_lock (&open->lock);
+
+  switch (whence)
+    {
+    case SEEK_SET:
+      open->offs = offs; break;
+    case SEEK_CUR:
+      open->offs += offs; break;
+    case SEEK_END:
+      open->offs = open->dev->store->size - offs; break;
+    default:
+      err = EINVAL;
+    }
+
+  if (! err)
+    *new_offs = open->offs;
+
+  mutex_unlock (&open->lock);
+
+  return err;
+}