diff options
Diffstat (limited to 'libc/stdio/setvbuf.c')
| -rw-r--r-- | libc/stdio/setvbuf.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/libc/stdio/setvbuf.c b/libc/stdio/setvbuf.c new file mode 100644 index 0000000..9b92bf0 --- /dev/null +++ b/libc/stdio/setvbuf.c @@ -0,0 +1,151 @@ +/* $OpenBSD: setvbuf.c,v 1.8 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 <stdlib.h> +#include "local.h" + +/* + * Set one of the three kinds of buffering, optionally including + * a buffer. + */ +int +setvbuf(FILE *fp, char *buf, int mode, size_t size) +{ + int ret, flags; + size_t iosize; + int ttyflag; + + /* + * Verify arguments. The `int' limit on `size' is due to this + * particular implementation. Note, buf and size are ignored + * when setting _IONBF. + */ + if (mode != _IONBF) + if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) + return (EOF); + + /* + * Write current buffer, if any. Discard unread input (including + * ungetc data), cancel line buffering, and free old buffer if + * malloc()ed. We also clear any eof condition, as if this were + * a seek. + */ + ret = 0; + (void)__sflush(fp); + if (HASUB(fp)) + FREEUB(fp); + WCIO_FREE(fp); + fp->_r = fp->_lbfsize = 0; + flags = fp->_flags; + if (flags & __SMBF) + free((void *)fp->_bf._base); + flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF); + + /* If setting unbuffered mode, skip all the hard work. */ + if (mode == _IONBF) + goto nbf; + + /* + * Find optimal I/O size for seek optimization. This also returns + * a `tty flag' to suggest that we check isatty(fd), but we do not + * care since our caller told us how to buffer. + */ + flags |= __swhatbuf(fp, &iosize, &ttyflag); + if (size == 0) { + buf = NULL; /* force local allocation */ + size = iosize; + } + + /* Allocate buffer if needed. */ + if (buf == NULL) { + if ((buf = malloc(size)) == NULL) { + /* + * Unable to honor user's request. We will return + * failure, but try again with file system size. + */ + ret = EOF; + if (size != iosize) { + size = iosize; + buf = malloc(size); + } + } + if (buf == NULL) { + /* No luck; switch to unbuffered I/O. */ +nbf: + fp->_flags = flags | __SNBF; + fp->_w = 0; + fp->_bf._base = fp->_p = fp->_nbuf; + fp->_bf._size = 1; + return (ret); + } + flags |= __SMBF; + } + + /* + * Kill any seek optimization if the buffer is not the + * right size. + * + * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? + */ + if (size != iosize) + flags |= __SNPT; + + /* + * Fix up the FILE fields, and set __cleanup for output flush on + * exit (since we are buffered in some way). + */ + if (mode == _IOLBF) + flags |= __SLBF; + fp->_flags = flags; + fp->_bf._base = fp->_p = (unsigned char *)buf; + fp->_bf._size = size; + /* fp->_lbfsize is still 0 */ + if (flags & __SWR) { + /* + * Begin or continue writing: see __swsetup(). Note + * that __SNBF is impossible (it was handled earlier). + */ + if (flags & __SLBF) { + fp->_w = 0; + fp->_lbfsize = -fp->_bf._size; + } else + fp->_w = size; + } else { + /* begin/continue reading, or stay in intermediate state */ + fp->_w = 0; + } + __atexit_register_cleanup(_cleanup); + + return (ret); +} |