1/*
2 * Copyright (c) 2000-2001 Sendmail, 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#pragma ident	"%Z%%M%	%I%	%E% SMI"
16
17#include <sm/gen.h>
18SM_RCSID("@(#)$Id: wbuf.c,v 1.19 2001/03/05 03:22:41 ca Exp $")
19#include <errno.h>
20#include <sm/io.h>
21#include "local.h"
22
23/* Note: This function is called from a macro located in <sm/io.h> */
24
25/*
26**  SM_WBUF -- write character to and flush (likely now full) buffer
27**
28**  Write the given character into the (probably full) buffer for
29**  the given file.  Flush the buffer out if it is or becomes full,
30**  or if c=='\n' and the file is line buffered.
31**
32**	Parameters:
33**		fp -- the file pointer
34**		timeout -- time to complete operation (milliseconds)
35**		c -- int representation of the character to add
36**
37**	Results:
38**		Failure: -1 and sets errno
39**		Success: int value of 'c'
40*/
41
42int
43sm_wbuf(fp, timeout, c)
44	register SM_FILE_T *fp;
45	int timeout;
46	register int c;
47{
48	register int n;
49
50	/*
51	**  In case we cannot write, or longjmp takes us out early,
52	**  make sure w is 0 (if fully- or un-buffered) or -bf.smb_size
53	**  (if line buffered) so that we will get called again.
54	**  If we did not do this, a sufficient number of sm_io_putc()
55	**  calls might wrap w from negative to positive.
56	*/
57
58	fp->f_w = fp->f_lbfsize;
59	if (cantwrite(fp))
60	{
61		errno = EBADF;
62		return SM_IO_EOF;
63	}
64	c = (unsigned char)c;
65
66	/*
67	**  If it is completely full, flush it out.  Then, in any case,
68	**  stuff c into the buffer.  If this causes the buffer to fill
69	**  completely, or if c is '\n' and the file is line buffered,
70	**  flush it (perhaps a second time).  The second flush will always
71	**  happen on unbuffered streams, where bf.smb_size==1; sm_io_flush()
72	**  guarantees that sm_io_putc() will always call sm_wbuf() by setting
73	**  w to 0, so we need not do anything else.
74	**  Note for the timeout, only one of the sm_io_flush's will get called.
75	*/
76
77	n = fp->f_p - fp->f_bf.smb_base;
78	if (n >= fp->f_bf.smb_size)
79	{
80		if (sm_io_flush(fp, timeout))
81			return SM_IO_EOF; /* sm_io_flush() sets errno */
82		n = 0;
83	}
84	fp->f_w--;
85	*fp->f_p++ = c;
86	if (++n == fp->f_bf.smb_size || (fp->f_flags & SMLBF && c == '\n'))
87		if (sm_io_flush(fp, timeout))
88			return SM_IO_EOF; /* sm_io_flush() sets errno */
89	return c;
90}
91