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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)wbuf.c 8.1 (Berkeley) 6/4/93 33 * $FreeBSD: src/lib/libc/stdio/wbuf.c,v 1.12 2007/01/09 00:28:08 imp Exp $ 34 * $DragonFly: src/lib/libc/stdio/wbuf.c,v 1.6 2005/07/23 20:23:06 joerg Exp $ 35 */ 36 37 #include <stdio.h> 38 #include "local.h" 39 #include "priv_stdio.h" 40 41 /* 42 * Write the given character into the (probably full) buffer for 43 * the given file. Flush the buffer out if it is or becomes full, 44 * or if c=='\n' and the file is line buffered. 45 * 46 * Non-MT-safe 47 */ 48 int 49 __swbuf(int c, FILE *fp) 50 { 51 int n; 52 53 /* 54 * In case we cannot write, or longjmp takes us out early, 55 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size 56 * (if line buffered) so that we will get called again. 57 * If we did not do this, a sufficient number of putc() 58 * calls might wrap _w from negative to positive. 59 */ 60 fp->pub._w = fp->pub._lbfsize; 61 if (prepwrite(fp) != 0) 62 return (EOF); 63 c = (unsigned char)c; 64 65 ORIENT(fp, -1); 66 67 /* 68 * If it is completely full, flush it out. Then, in any case, 69 * stuff c into the buffer. If this causes the buffer to fill 70 * completely, or if c is '\n' and the file is line buffered, 71 * flush it (perhaps a second time). The second flush will always 72 * happen on unbuffered streams, where _bf._size==1; fflush() 73 * guarantees that putc() will always call wbuf() by setting _w 74 * to 0, so we need not do anything else. 75 */ 76 n = fp->pub._p - fp->_bf._base; 77 if (n >= fp->_bf._size) { 78 if (__fflush(fp)) 79 return (EOF); 80 n = 0; 81 } 82 fp->pub._w--; 83 *fp->pub._p++ = c; 84 if (++n == fp->_bf._size || (fp->pub._flags & __SLBF && c == '\n')) 85 if (__fflush(fp)) 86 return (EOF); 87 return (c); 88 } 89