1/*
2 * Copyright (c) 2000-2001 Proofpoint, Inc. and its suppliers.
3 *      All rights reserved.
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * By using this file, you agree to the terms and conditions set
11 * forth in the LICENSE file which can be found at the top level of
12 * the sendmail distribution.
13 */
14
15#include <sm/gen.h>
16SM_RCSID("@(#)$Id: wbuf.c,v 1.22 2013-11-22 20:51:44 ca Exp $")
17#include <errno.h>
18#include <sm/io.h>
19#include "local.h"
20
21/* Note: This function is called from a macro located in <sm/io.h> */
22
23/*
24**  SM_WBUF -- write character to and flush (likely now full) buffer
25**
26**  Write the given character into the (probably full) buffer for
27**  the given file.  Flush the buffer out if it is or becomes full,
28**  or if c=='\n' and the file is line buffered.
29**
30**	Parameters:
31**		fp -- the file pointer
32**		timeout -- time to complete operation (milliseconds)
33**		c -- int representation of the character to add
34**
35**	Results:
36**		Failure: -1 and sets errno
37**		Success: int value of 'c'
38*/
39
40int
41sm_wbuf(fp, timeout, c)
42	register SM_FILE_T *fp;
43	int timeout;
44	register int c;
45{
46	register int n;
47
48	/*
49	**  In case we cannot write, or longjmp takes us out early,
50	**  make sure w is 0 (if fully- or un-buffered) or -bf.smb_size
51	**  (if line buffered) so that we will get called again.
52	**  If we did not do this, a sufficient number of sm_io_putc()
53	**  calls might wrap w from negative to positive.
54	*/
55
56	fp->f_w = fp->f_lbfsize;
57	if (cantwrite(fp))
58	{
59		errno = EBADF;
60		return SM_IO_EOF;
61	}
62	c = (unsigned char)c;
63
64	/*
65	**  If it is completely full, flush it out.  Then, in any case,
66	**  stuff c into the buffer.  If this causes the buffer to fill
67	**  completely, or if c is '\n' and the file is line buffered,
68	**  flush it (perhaps a second time).  The second flush will always
69	**  happen on unbuffered streams, where bf.smb_size==1; sm_io_flush()
70	**  guarantees that sm_io_putc() will always call sm_wbuf() by setting
71	**  w to 0, so we need not do anything else.
72	**  Note for the timeout, only one of the sm_io_flush's will get called.
73	*/
74
75	n = fp->f_p - fp->f_bf.smb_base;
76	if (n >= fp->f_bf.smb_size)
77	{
78		if (sm_io_flush(fp, timeout))
79			return SM_IO_EOF; /* sm_io_flush() sets errno */
80		n = 0;
81	}
82	fp->f_w--;
83	*fp->f_p++ = c;
84	if (++n == fp->f_bf.smb_size || (fp->f_flags & SMLBF && c == '\n'))
85		if (sm_io_flush(fp, timeout))
86			return SM_IO_EOF; /* sm_io_flush() sets errno */
87	return c;
88}
89