/*	$OpenBSD: iobuf.c,v 1.1 2014/01/27 15:49:52 sunil Exp $	*/

/*      

 * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include <sys/types.h>

#include <sys/socket.h>

#include <sys/uio.h>

#include <errno.h>

#include <limits.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#ifdef IO_SSL

#include <openssl/err.h>

#include <openssl/ssl.h>

#endif

#include "iobuf.h"

#define IOBUF_MAX	65536

#define IOBUFQ_MIN	4096

struct ioqbuf	*ioqbuf_alloc(struct iobuf *, size_t);

void		 iobuf_drain(struct iobuf *, size_t);

int

iobuf_init(struct iobuf *io, size_t size, size_t max)

{

	memset(io, 0, sizeof *io);

	if (max == 0)

		max = IOBUF_MAX;

	if (size == 0)

		size = max;

	if (size > max)

		return (-1);

	if ((io->buf = malloc(size)) == NULL)

		return (-1);

	io->size = size;

	io->max = max;

	return (0);

}

void

iobuf_clear(struct iobuf *io)

{

	struct ioqbuf	*q;

	if (io->buf)

		free(io->buf);

	while ((q = io->outq)) {

		io->outq = q->next;

		free(q);

	}

	memset(io, 0, sizeof (*io));

}

void

iobuf_drain(struct iobuf *io, size_t n)

{

	struct	ioqbuf	*q;

	size_t		 left = n;

	while ((q = io->outq) && left) {

		if ((q->wpos - q->rpos) > left) {

			q->rpos += left;

			left = 0;

		} else {

			left -= q->wpos - q->rpos;

			io->outq = q->next;

			free(q);

		}

	}

	io->queued -= (n - left);

	if (io->outq == NULL)

		io->outqlast = NULL;

}

int

iobuf_extend(struct iobuf *io, size_t n)

{

	char	*t;

	if (n > io->max)

		return (-1);

	if (io->max - io->size < n)

		return (-1);

	t = realloc(io->buf, io->size + n);

	if (t == NULL)

		return (-1);

	io->size += n;

	io->buf = t;

	return (0);

}

size_t

iobuf_left(struct iobuf *io)

{

	return io->size - io->wpos;

}

size_t

iobuf_space(struct iobuf *io)

{

	return io->size - (io->wpos - io->rpos);

}

size_t

iobuf_len(struct iobuf *io)

{

	return io->wpos - io->rpos;

}

char *

iobuf_data(struct iobuf *io)

{

	return io->buf + io->rpos;

}

void

iobuf_drop(struct iobuf *io, size_t n)

{

	if (n >= iobuf_len(io)) {

		io->rpos = io->wpos = 0;

		return;

	}

	io->rpos += n;

}

char *

iobuf_getline(struct iobuf *iobuf, size_t *rlen)

{

	char	*buf;

	size_t	 len, i;

	buf = iobuf_data(iobuf);

	len = iobuf_len(iobuf);

	for (i = 0; i + 1 <= len; i++)

		if (buf[i] == '\n') {

			/* Note: the returned address points into the iobuf

			 * buffer.  We NUL-end it for convenience, and discard

			 * the data from the iobuf, so that the caller doesn't

			 * have to do it.  The data remains "valid" as long

			 * as the iobuf does not overwrite it, that is until

			 * the next call to iobuf_normalize() or iobuf_extend().

			 */

			iobuf_drop(iobuf, i + 1);

			len = (i && buf[i - 1] == '\r') ? i - 1 : i;

			buf[len] = '\0';

			if (rlen)

				*rlen = len;

			return (buf);

		}

	return (NULL);

}

void

iobuf_normalize(struct iobuf *io)

{

	if (io->rpos == 0)

		return;

	if (io->rpos == io->wpos) {

		io->rpos = io->wpos = 0;

		return;

	}

	memmove(io->buf, io->buf + io->rpos, io->wpos - io->rpos);

	io->wpos -= io->rpos;

	io->rpos = 0;

}

ssize_t

iobuf_read(struct iobuf *io, int fd)

{

	ssize_t	n;

	n = read(fd, io->buf + io->wpos, iobuf_left(io));

	if (n == -1) {

		/* XXX is this really what we want? */

		if (errno == EAGAIN || errno == EINTR)

			return (IOBUF_WANT_READ);

		return (IOBUF_ERROR);

	}

	if (n == 0)

		return (IOBUF_CLOSED);

	io->wpos += n;

	return (n);

}

struct ioqbuf *

ioqbuf_alloc(struct iobuf *io, size_t len)

{

	struct ioqbuf   *q;

	if (len < IOBUFQ_MIN)

		len = IOBUFQ_MIN;

	if ((q = malloc(sizeof(*q) + len)) == NULL)

		return (NULL);

	q->rpos = 0;

	q->wpos = 0;

	q->size = len;

	q->next = NULL;

	q->buf = (char *)(q) + sizeof(*q);

	if (io->outqlast == NULL)

		io->outq = q;

	else

		io->outqlast->next = q;

	io->outqlast = q;

	return (q);

}

size_t

iobuf_queued(struct iobuf *io)

{

	return io->queued;

}

void *

iobuf_reserve(struct iobuf *io, size_t len)

{

	struct ioqbuf	*q;

	void		*r;

	if (len == 0)

		return (NULL);

	if (((q = io->outqlast) == NULL) || q->size - q->wpos <= len) {

		if ((q = ioqbuf_alloc(io, len)) == NULL)

			return (NULL);

	}

	r = q->buf + q->wpos;

	q->wpos += len;

	io->queued += len;

	return (r);

}

int

iobuf_queue(struct iobuf *io, const void *data, size_t len)

{

	void	*buf;

	if (len == 0)

		return (0);

	if ((buf = iobuf_reserve(io, len)) == NULL)

		return (-1);

	memmove(buf, data, len);

	return (0);

}

int

iobuf_queuev(struct iobuf *io, const struct iovec *iov, int iovcnt)

{

	int	 i;

	size_t	 len = 0;

	char	*buf;

	for (i = 0; i < iovcnt; i++)

		len += iov[i].iov_len;

	if ((buf = iobuf_reserve(io, len)) == NULL)

		return (-1);

	for (i = 0; i < iovcnt; i++) {

		if (iov[i].iov_len == 0)

			continue;

		memmove(buf, iov[i].iov_base, iov[i].iov_len);

		buf += iov[i].iov_len;

	}

	return (0);

}

int

iobuf_fqueue(struct iobuf *io, const char *fmt, ...)

{

	va_list	ap;

	int	len;

	va_start(ap, fmt);

	len = iobuf_vfqueue(io, fmt, ap);

	va_end(ap);

	return (len);

}

int

iobuf_vfqueue(struct iobuf *io, const char *fmt, va_list ap)

{

	char	*buf;

	int	 len;

	len = vasprintf(&buf, fmt, ap);

	if (len == -1)

		return (-1);

	len = iobuf_queue(io, buf, len);

	free(buf);

	return (len);

}

ssize_t

iobuf_write(struct iobuf *io, int fd)

{

	struct iovec	 iov[IOV_MAX];

	struct ioqbuf	*q;

	int		 i;

	ssize_t		 n;

	i = 0;

	for (q = io->outq; q ; q = q->next) {

		if (i >= IOV_MAX)

			break;

		iov[i].iov_base = q->buf + q->rpos;

		iov[i].iov_len = q->wpos - q->rpos;

		i++;

	}

	n = writev(fd, iov, i);

	if (n == -1) {

		if (errno == EAGAIN || errno == EINTR)

			return (IOBUF_WANT_WRITE);

		if (errno == EPIPE)

			return (IOBUF_CLOSED);

		return (IOBUF_ERROR);

	}

	iobuf_drain(io, n);

	return (n);

}

int

iobuf_flush(struct iobuf *io, int fd)

{