1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 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 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)wbuf.c 8.1 (Berkeley) 6/4/93"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include <errno.h> 42 #include <stdio.h> 43 #include "local.h" 44 45 /* 46 * Write the given character into the (probably full) buffer for 47 * the given file. Flush the buffer out if it is or becomes full, 48 * or if c=='\n' and the file is line buffered. 49 * 50 * Non-MT-safe 51 */ 52 int 53 __swbuf(int c, FILE *fp) 54 { 55 unsigned char *old_p; 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->_w = fp->_lbfsize; 66 if (prepwrite(fp) != 0) { 67 errno = EBADF; 68 return (EOF); 69 } 70 c = (unsigned char)c; 71 72 ORIENT(fp, -1); 73 74 /* 75 * If it is completely full, flush it out. Then, in any case, 76 * stuff c into the buffer. If this causes the buffer to fill 77 * completely, or if c is '\n' and the file is line buffered, 78 * flush it (perhaps a second time). The second flush will always 79 * happen on unbuffered streams, where _bf._size==1; fflush() 80 * guarantees that putc() will always call wbuf() by setting _w 81 * to 0, so we need not do anything else. 82 */ 83 n = fp->_p - fp->_bf._base; 84 if (n >= fp->_bf._size) { 85 if (__fflush(fp) != 0) 86 return (EOF); 87 n = 0; 88 } 89 fp->_w--; 90 *fp->_p++ = c; 91 old_p = fp->_p; 92 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n')) { 93 if (__fflush(fp) != 0) { 94 if (fp->_p == old_p && errno == EINTR) { 95 fp->_p--; 96 fp->_w++; 97 } 98 return (EOF); 99 } 100 } 101 return (c); 102 } 103