1 files changed, 82 insertions, 0 deletions
diff --git a/devio/window.h b/devio/window.h
new file mode 100644
index 00000000..4bd6301c
--- /dev/null
+++ b/devio/window.h
@@ -0,0 +1,82 @@
+/* Window management routines for buffered I/O using VM.
+
+   Copyright (C) 1995 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. */
+
+#ifndef __WINDOW_H__
+#define __WINDOW_H__
+
+#include <mach.h>
+
+/* ---------------------------------------------------------------- */
+
+/* A structure describing a memory window used to do buffered random access
+   device i/o through the device pager.  */
+struct window
+{
+  /* The currently allocated vm window backed by the device pager.  */
+  vm_address_t buffer;
+
+  /* The device offset of the window.  */
+  vm_offset_t location;
+
+  /* The length of the window (should be a multiple of __vm_page_size).  If
+     this is 0, this window isn't allocated.  */
+  vm_size_t size;
+  /* If SIZE < MIN_SIZE we won't shrink the window.  */
+  vm_size_t min_size;
+  /* If SIZE > MAX_SIZE, we'll try and shrink the window to fit.  */
+  vm_size_t max_size;
+
+  /* The device pager providing backing store for this window.  */
+  mach_port_t memobj;
+  /* True if the mapping should be read_only.  */
+  int read_only;
+
+  /* Lock this if you want to read/write some field(s) here.  */
+  struct mutex lock;
+};
+
+/* Create a VM window onto the memory object MEMOBJ, and return it in WIN.
+   MIN_SIZE and MAX_SIZE are the minimum and maximum sizes that the window
+   will shrink/grow to.  */
+error_t window_create(mach_port_t memobj,
+		      vm_size_t min_size, vm_size_t max_size, int read_only,
+		      struct window **win);
+
+/* Free WIN and any resources it holds.  */
+void window_free(struct window *win);
+
+/* Write up to BUF_LEN bytes from BUF to the device that WIN is a window on,
+   at offset *OFFS, using memory-mapped buffered I/O.  If successful, 0 is
+   returned, otherwise an error code is returned.  *OFFS is incremented by
+   the amount sucessfully written.  */
+error_t window_write(struct window *win,
+		     vm_address_t buf, vm_size_t buf_len, vm_size_t *amount,
+		     vm_offset_t *offs);
+
+/* Read up to AMOUNT bytes from the device that WIN is a window on, at offset
+   *OFFS, into BUF and BUF_LEN (using the standard mach out-array
+   conventions), using memory-mapped buffered I/O.  If successful, 0 is
+   returned, otherwise an error code is returned.  *OFFS is incremented by
+   the amount sucessfully written.  */
+error_t window_read(struct window *win,
+		    vm_address_t *buf, vm_size_t *buf_len,
+		    vm_size_t amount, vm_offset_t *offs);
+
+#endif /* !__WINDOW_H__ */