diff options
Diffstat (limited to 'libc/stdio/wbuf.c')
-rw-r--r-- | libc/stdio/wbuf.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/libc/stdio/wbuf.c b/libc/stdio/wbuf.c new file mode 100644 index 0000000..c757799 --- /dev/null +++ b/libc/stdio/wbuf.c @@ -0,0 +1,84 @@ +/* $OpenBSD: wbuf.c,v 1.9 2005/08/08 08:05:36 espie Exp $ */ +/*- + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Chris Torek. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <stdio.h> +#include <errno.h> +#include "local.h" + +/* + * Write the given character into the (probably full) buffer for + * the given file. Flush the buffer out if it is or becomes full, + * or if c=='\n' and the file is line buffered. + */ +int +__swbuf(int c, FILE *fp) +{ + int n; + + _SET_ORIENTATION(fp, -1); + /* + * In case we cannot write, or longjmp takes us out early, + * make sure _w is 0 (if fully- or un-buffered) or -_bf._size + * (if line buffered) so that we will get called again. + * If we did not do this, a sufficient number of putc() + * calls might wrap _w from negative to positive. + */ + fp->_w = fp->_lbfsize; + if (cantwrite(fp)) { + errno = EBADF; + return (EOF); + } + c = (unsigned char)c; + + /* + * If it is completely full, flush it out. Then, in any case, + * stuff c into the buffer. If this causes the buffer to fill + * completely, or if c is '\n' and the file is line buffered, + * flush it (perhaps a second time). The second flush will always + * happen on unbuffered streams, where _bf._size==1; fflush() + * guarantees that putc() will always call wbuf() by setting _w + * to 0, so we need not do anything else. + */ + n = fp->_p - fp->_bf._base; + if (n >= fp->_bf._size) { + if (fflush(fp)) + return (EOF); + n = 0; + } + fp->_w--; + *fp->_p++ = c; + if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n')) + if (fflush(fp)) + return (EOF); + return (c); +} |