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. 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 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)wbuf.c 8.1 (Berkeley) 6/4/93"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include <errno.h> 40 #include <stdio.h> 41 #include "local.h" 42 43 /* 44 * Write the given character into the (probably full) buffer for 45 * the given file. Flush the buffer out if it is or becomes full, 46 * or if c=='\n' and the file is line buffered. 47 * 48 * Non-MT-safe 49 */ 50 int 51 __swbuf(int c, FILE *fp) 52 { 53 int n; 54 55 /* 56 * In case we cannot write, or longjmp takes us out early, 57 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size 58 * (if line buffered) so that we will get called again. 59 * If we did not do this, a sufficient number of putc() 60 * calls might wrap _w from negative to positive. 61 */ 62 fp->_w = fp->_lbfsize; 63 if (prepwrite(fp) != 0) { 64 errno = EBADF; 65 return (EOF); 66 } 67 c = (unsigned char)c; 68 69 ORIENT(fp, -1); 70 71 /* 72 * If it is completely full, flush it out. Then, in any case, 73 * stuff c into the buffer. If this causes the buffer to fill 74 * completely, or if c is '\n' and the file is line buffered, 75 * flush it (perhaps a second time). The second flush will always 76 * happen on unbuffered streams, where _bf._size==1; fflush() 77 * guarantees that putc() will always call wbuf() by setting _w 78 * to 0, so we need not do anything else. 79 */ 80 n = fp->_p - fp->_bf._base; 81 if (n >= fp->_bf._size) { 82 if (__fflush(fp)) 83 return (EOF); 84 n = 0; 85 } 86 fp->_w--; 87 *fp->_p++ = c; 88 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n')) 89 if (__fflush(fp)) 90 return (EOF); 91 return (c); 92 } 93