wbuf.c revision 101776
11573Srgrimes/*- 21573Srgrimes * Copyright (c) 1990, 1993 31573Srgrimes * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * This code is derived from software contributed to Berkeley by 61573Srgrimes * Chris Torek. 71573Srgrimes * 81573Srgrimes * Redistribution and use in source and binary forms, with or without 91573Srgrimes * modification, are permitted provided that the following conditions 101573Srgrimes * are met: 111573Srgrimes * 1. Redistributions of source code must retain the above copyright 121573Srgrimes * notice, this list of conditions and the following disclaimer. 131573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141573Srgrimes * notice, this list of conditions and the following disclaimer in the 151573Srgrimes * documentation and/or other materials provided with the distribution. 161573Srgrimes * 3. All advertising materials mentioning features or use of this software 171573Srgrimes * must display the following acknowledgement: 181573Srgrimes * This product includes software developed by the University of 191573Srgrimes * California, Berkeley and its contributors. 201573Srgrimes * 4. Neither the name of the University nor the names of its contributors 211573Srgrimes * may be used to endorse or promote products derived from this software 221573Srgrimes * without specific prior written permission. 231573Srgrimes * 241573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 251573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 261573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 271573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 281573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 291573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 301573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 311573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 321573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 331573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 341573Srgrimes * SUCH DAMAGE. 351573Srgrimes */ 361573Srgrimes 371573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 381573Srgrimesstatic char sccsid[] = "@(#)wbuf.c 8.1 (Berkeley) 6/4/93"; 391573Srgrimes#endif /* LIBC_SCCS and not lint */ 4092986Sobrien#include <sys/cdefs.h> 4192986Sobrien__FBSDID("$FreeBSD: head/lib/libc/stdio/wbuf.c 101776 2002-08-13 09:30:41Z tjr $"); 421573Srgrimes 431573Srgrimes#include <stdio.h> 441573Srgrimes#include "local.h" 451573Srgrimes 461573Srgrimes/* 471573Srgrimes * Write the given character into the (probably full) buffer for 481573Srgrimes * the given file. Flush the buffer out if it is or becomes full, 491573Srgrimes * or if c=='\n' and the file is line buffered. 5071579Sdeischen * 5171579Sdeischen * Non-MT-safe 521573Srgrimes */ 5316586Sjraynardint 5416586Sjraynard__swbuf(c, fp) 5592889Sobrien int c; 5692889Sobrien FILE *fp; 571573Srgrimes{ 5892889Sobrien int n; 591573Srgrimes 601573Srgrimes /* 611573Srgrimes * In case we cannot write, or longjmp takes us out early, 621573Srgrimes * make sure _w is 0 (if fully- or un-buffered) or -_bf._size 631573Srgrimes * (if line buffered) so that we will get called again. 641573Srgrimes * If we did not do this, a sufficient number of putc() 651573Srgrimes * calls might wrap _w from negative to positive. 661573Srgrimes */ 671573Srgrimes fp->_w = fp->_lbfsize; 681573Srgrimes if (cantwrite(fp)) 691573Srgrimes return (EOF); 701573Srgrimes c = (unsigned char)c; 711573Srgrimes 72101776Stjr ORIENT(fp, -1); 73101776Stjr 741573Srgrimes /* 751573Srgrimes * If it is completely full, flush it out. Then, in any case, 761573Srgrimes * stuff c into the buffer. If this causes the buffer to fill 771573Srgrimes * completely, or if c is '\n' and the file is line buffered, 781573Srgrimes * flush it (perhaps a second time). The second flush will always 791573Srgrimes * happen on unbuffered streams, where _bf._size==1; fflush() 801573Srgrimes * guarantees that putc() will always call wbuf() by setting _w 811573Srgrimes * to 0, so we need not do anything else. 821573Srgrimes */ 831573Srgrimes n = fp->_p - fp->_bf._base; 841573Srgrimes if (n >= fp->_bf._size) { 8571579Sdeischen if (__fflush(fp)) 861573Srgrimes return (EOF); 871573Srgrimes n = 0; 881573Srgrimes } 891573Srgrimes fp->_w--; 901573Srgrimes *fp->_p++ = c; 911573Srgrimes if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n')) 9271579Sdeischen if (__fflush(fp)) 931573Srgrimes return (EOF); 941573Srgrimes return (c); 951573Srgrimes} 96