1 files changed, 68 insertions, 0 deletions
diff --git a/libpipe/stream.c b/libpipe/stream.c
new file mode 100644
index 00000000..8eb90435
--- /dev/null
+++ b/libpipe/stream.c
@@ -0,0 +1,68 @@
+/* The SOCK_STREAM pipe class
+
+   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. */
+
+#include <sys/socket.h>		/* For SOCK_STREAM */
+
+#include "pipe.h"
+#include "pq.h"
+
+/* See the definition of struct pipe_class in "pipe.h" for an explanation.  */
+
+/* This should be in some system header...  XXX  */
+static inline int page_aligned (vm_offset_t num)
+{
+  return trunc_page (num) == num;
+}
+
+static error_t 
+stream_write (struct pq *pq, void *source,
+	      char *data, size_t data_len, size_t *amount)
+{
+  struct packet *packet = pq_tail (pq, PACKET_TYPE_DATA, source);
+
+  if (packet_readable (packet) > 0
+      && data_len > PACKET_SIZE_LARGE
+      && (! page_aligned (data - packet->buf_end)
+	  || ! packet_ensure_efficiently (packet, data_len)))
+    /* Put a large page-aligned transfer in its own packet, if it's
+       page-aligned `differently' than the end of the current packet, or if
+       the current packet can't be extended in place.  */
+    packet = pq_queue (pq, PACKET_TYPE_DATA, source);
+
+  if (!packet)
+    return ENOBUFS;
+  else
+    return packet_write (packet, data, data_len, amount);
+}
+
+static error_t 
+stream_read (struct packet *packet, int *dequeue, unsigned *flags,
+	     char **data, size_t *data_len, size_t amount)
+{
+  error_t err = packet_read (packet, data, data_len, amount);
+  *dequeue = (packet_readable (packet) == 0);
+  return err;
+}
+
+struct pipe_class _stream_pipe_class =
+{
+  SOCK_STREAM, 0, stream_read, stream_write
+};
+struct pipe_class *stream_pipe_class = &_stream_pipe_class;