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 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 <stdio.h> 40 #include "local.h" 41 42 /* 43 * Write the given character into the (probably full) buffer for 44 * the given file. Flush the buffer out if it is or becomes full, 45 * or if c=='\n' and the file is line buffered. 46 * 47 * Non-MT-safe 48 */ 49 int 50 __swbuf(c, fp) 51 int c; 52 FILE *fp; 53 { 54 int n; 55 56 /* 57 * In case we cannot write, or longjmp takes us out early, 58 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size 59 * (if line buffered) so that we will get called again. 60 * If we did not do this, a sufficient number of putc() 61 * calls might wrap _w from negative to positive. 62 */ 63 fp->_w = fp->_lbfsize; 64 if (prepwrite(fp) != 0) 65 return (EOF); 66 c = (unsigned char)c; 67 68 ORIENT(fp, -1); 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->_p - fp->_bf._base; 80 if (n >= fp->_bf._size) { 81 if (__fflush(fp)) 82 return (EOF); 83 n = 0; 84 } 85 fp->_w--; 86 *fp->_p++ = c; 87 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n')) 88 if (__fflush(fp)) 89 return (EOF); 90 return (c); 91 } 92