1/* $OpenBSD: wbuf.c,v 1.14 2023/10/06 16:41:02 millert Exp $ */ 2/*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#include <stdio.h> 35#include "local.h" 36 37/* 38 * Write the given character into the (probably full) buffer for 39 * the given file. Flush the buffer out if it is or becomes full, 40 * or if c=='\n' and the file is line buffered. 41 */ 42int 43__swbuf(int c, FILE *fp) 44{ 45 int n; 46 47 _SET_ORIENTATION(fp, -1); 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._size 51 * (if line buffered) so that we will get called again. 52 * If we did not do this, a sufficient number of putc() 53 * calls might wrap _w from negative to positive. 54 */ 55 fp->_w = fp->_lbfsize; 56 if (cantwrite(fp)) 57 return (EOF); 58 c = (unsigned char)c; 59 60 /* 61 * If it is completely full, flush it out. Then, in any case, 62 * stuff c into the buffer. If this causes the buffer to fill 63 * completely, or if c is '\n' and the file is line buffered, 64 * flush it (perhaps a second time). The second flush will always 65 * happen on unbuffered streams, where _bf._size==1; __sflush() 66 * guarantees that putc() will always call wbuf() by setting _w 67 * to 0, so we need not do anything else. 68 */ 69 n = fp->_p - fp->_bf._base; 70 if (n >= fp->_bf._size) { 71 if (__sflush(fp)) 72 return (EOF); 73 n = 0; 74 } 75 fp->_w--; 76 *fp->_p++ = c; 77 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n')) 78 if (__sflush(fp)) 79 return (EOF); 80 return (c); 81} 82DEF_STRONG(__swbuf); 83