1 /* $NetBSD: wbuf.c,v 1.13 2003/08/07 16:43:35 agc Exp $ */ 2 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 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)wbuf.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: wbuf.c,v 1.13 2003/08/07 16:43:35 agc Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 #include "reentrant.h" 48 #include "local.h" 49 50 /* 51 * Write the given character into the (probably full) buffer for 52 * the given file. Flush the buffer out if it is or becomes full, 53 * or if c=='\n' and the file is line buffered. 54 */ 55 int 56 __swbuf(c, fp) 57 int c; 58 FILE *fp; 59 { 60 int n; 61 62 _DIAGASSERT(fp != NULL); 63 64 _SET_ORIENTATION(fp, -1); 65 66 /* 67 * In case we cannot write, or longjmp takes us out early, 68 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size 69 * (if line buffered) so that we will get called again. 70 * If we did not do this, a sufficient number of putc() 71 * calls might wrap _w from negative to positive. 72 */ 73 fp->_w = fp->_lbfsize; 74 if (cantwrite(fp)) { 75 errno = EBADF; 76 return (EOF); 77 } 78 c = (unsigned char)c; 79 80 /* 81 * If it is completely full, flush it out. Then, in any case, 82 * stuff c into the buffer. If this causes the buffer to fill 83 * completely, or if c is '\n' and the file is line buffered, 84 * flush it (perhaps a second time). The second flush will always 85 * happen on unbuffered streams, where _bf._size==1; fflush() 86 * guarantees that putc() will always call wbuf() by setting _w 87 * to 0, so we need not do anything else. 88 */ 89 n = fp->_p - fp->_bf._base; 90 if (n >= fp->_bf._size) { 91 if (fflush(fp)) 92 return (EOF); 93 n = 0; 94 } 95 fp->_w--; 96 *fp->_p++ = c; 97 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n')) 98 if (fflush(fp)) 99 return (EOF); 100 return (c); 101 } 102