1 /*
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are permitted
6 * provided that the above copyright notice and this paragraph are
7 * duplicated in all such forms and that any documentation,
8 * and/or other materials related to such
9 * distribution and use acknowledge that the software was developed
10 * by the University of California, Berkeley. The name of the
11 * University may not be used to endorse or promote products derived
12 * from this software without specific prior written permission.
13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16 */
17 /* No user fns here. Pesch 15apr92. */
18
19 #if defined(LIBC_SCCS) && !defined(lint)
20 static char sccsid[] = "%W% (Berkeley) %G%";
21 #endif /* LIBC_SCCS and not lint */
22
23 #define _DEFAULT_SOURCE
24 #include <stdio.h>
25 #include <errno.h>
26 #include "local.h"
27 #include "fvwrite.h"
28
29 /*
30 * Write the given character into the (probably full) buffer for
31 * the given file. Flush the buffer out if it is or becomes full,
32 * or if c=='\n' and the file is line buffered.
33 */
34
35 int
_swbuf(register int c,register FILE * fp)36 _swbuf (
37 register int c,
38 register FILE *fp)
39 {
40 register int n;
41
42 /* Ensure stdio has been initialized. */
43
44 CHECK_INIT (ptr, fp);
45
46 /*
47 * In case we cannot write, or longjmp takes us out early,
48 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size
49 * (if line buffered) so that we will get called again.
50 * If we did not do this, a sufficient number of putc()
51 * calls might wrap _w from negative to positive.
52 */
53
54 fp->_w = fp->_lbfsize;
55 if (cantwrite (ptr, fp))
56 return EOF;
57 c = (unsigned char) c;
58
59 if (ORIENT (fp, -1) != -1)
60 return EOF;
61
62 /*
63 * If it is completely full, flush it out. Then, in any case,
64 * stuff c into the buffer. If this causes the buffer to fill
65 * completely, or if c is '\n' and the file is line buffered,
66 * flush it (perhaps a second time). The second flush will always
67 * happen on unbuffered streams, where _bf._size==1; fflush()
68 * guarantees that putc() will always call wbuf() by setting _w
69 * to 0, so we need not do anything else.
70 */
71
72 n = fp->_p - fp->_bf._base;
73 if (n >= fp->_bf._size)
74 {
75 if (fflush ( fp))
76 return EOF;
77 n = 0;
78 }
79 fp->_w--;
80 *fp->_p++ = c;
81 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))
82 if (fflush ( fp))
83 return EOF;
84 return c;
85 }
86
