1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 /*static char *sccsid = "from: @(#)wbuf.c 5.6 (Berkeley) 1/20/91";*/ 39 static char *rcsid = "$Id: wbuf.c,v 1.3 1993/08/26 00:47:41 jtc Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 41 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 __swbuf(c, fp) 51 register int c; 52 register FILE *fp; 53 { 54 register 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 (cantwrite(fp)) 65 return (EOF); 66 c = (unsigned char)c; 67 68 /* 69 * If it is completely full, flush it out. Then, in any case, 70 * stuff c into the buffer. If this causes the buffer to fill 71 * completely, or if c is '\n' and the file is line buffered, 72 * flush it (perhaps a second time). The second flush will always 73 * happen on unbuffered streams, where _bf._size==1; fflush() 74 * guarantees that putc() will always call wbuf() by setting _w 75 * to 0, so we need not do anything else. 76 */ 77 n = fp->_p - fp->_bf._base; 78 if (n >= fp->_bf._size) { 79 if (fflush(fp)) 80 return (EOF); 81 n = 0; 82 } 83 fp->_w--; 84 *fp->_p++ = c; 85 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n')) 86 if (fflush(fp)) 87 return (EOF); 88 return (c); 89 } 90