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/* 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;
if (flags && *flags & MSG_PEEK)
{
err = packet_peek (packet, data, data_len, amount);
*dequeue = 0;
}
else
{
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;
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