1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)wbuf.c 8.1 (Berkeley) 6/4/93 37 * $FreeBSD: src/lib/libc/stdio/wbuf.c,v 1.6 1999/08/28 00:01:22 peter Exp $ 38 * $DragonFly: src/lib/libc/stdio/wbuf.c,v 1.6 2005/07/23 20:23:06 joerg Exp $ 39 */ 40 41 #include <stdio.h> 42 43 #include "local.h" 44 #include "priv_stdio.h" 45 46 /* 47 * Write the given character into the (probably full) buffer for 48 * the given file. Flush the buffer out if it is or becomes full, 49 * or if c=='\n' and the file is line buffered. 50 * 51 * Non-MT-safe 52 */ 53 int 54 __swbuf(int c, FILE *fp) 55 { 56 int n; 57 58 /* 59 * In case we cannot write, or longjmp takes us out early, 60 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size 61 * (if line buffered) so that we will get called again. 62 * If we did not do this, a sufficient number of putc() 63 * calls might wrap _w from negative to positive. 64 */ 65 fp->pub._w = fp->pub._lbfsize; 66 if (cantwrite(fp)) 67 return (EOF); 68 c = (unsigned char)c; 69 70 /* 71 * If it is completely full, flush it out. Then, in any case, 72 * stuff c into the buffer. If this causes the buffer to fill 73 * completely, or if c is '\n' and the file is line buffered, 74 * flush it (perhaps a second time). The second flush will always 75 * happen on unbuffered streams, where _bf._size==1; fflush() 76 * guarantees that putc() will always call wbuf() by setting _w 77 * to 0, so we need not do anything else. 78 */ 79 n = fp->pub._p - fp->_bf._base; 80 if (n >= fp->_bf._size) { 81 if (__fflush(fp)) 82 return (EOF); 83 n = 0; 84 } 85 fp->pub._w--; 86 *fp->pub._p++ = c; 87 if (++n == fp->_bf._size || (fp->pub._flags & __SLBF && c == '\n')) 88 if (__fflush(fp)) 89 return (EOF); 90 return (c); 91 } 92