diff options
Diffstat (limited to 'lib/libc/stdio/ftell.c')
-rw-r--r-- | lib/libc/stdio/ftell.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/lib/libc/stdio/ftell.c b/lib/libc/stdio/ftell.c new file mode 100644 index 0000000..a9ff6ed --- /dev/null +++ b/lib/libc/stdio/ftell.c @@ -0,0 +1,139 @@ +/*- + * 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. + * 4. 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. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)ftell.c 8.2 (Berkeley) 5/4/95"; +#endif /* LIBC_SCCS and not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "namespace.h" +#include <sys/types.h> +#include <errno.h> +#include <limits.h> +#include <stdio.h> +#include "un-namespace.h" +#include "local.h" +#include "libc_private.h" + +/* + * standard ftell function. + */ +long +ftell(fp) + FILE *fp; +{ + off_t rv; + + rv = ftello(fp); + if (rv > LONG_MAX) { + errno = EOVERFLOW; + return (-1); + } + return (rv); +} + +/* + * ftello: return current offset. + */ +off_t +ftello(fp) + FILE *fp; +{ + fpos_t rv; + int ret; + + FLOCKFILE(fp); + ret = _ftello(fp, &rv); + FUNLOCKFILE(fp); + if (ret) + return (-1); + if (rv < 0) { /* Unspecified value because of ungetc() at 0 */ + errno = ESPIPE; + return (-1); + } + return (rv); +} + +int +_ftello(fp, offset) + FILE *fp; + fpos_t *offset; +{ + fpos_t pos; + size_t n; + + if (fp->_seek == NULL) { + errno = ESPIPE; /* historic practice */ + return (1); + } + + /* + * Find offset of underlying I/O object, then + * adjust for buffered bytes. + */ + if (fp->_flags & __SOFF) + pos = fp->_offset; + else { + pos = _sseek(fp, (fpos_t)0, SEEK_CUR); + if (pos == -1) + return (1); + } + if (fp->_flags & __SRD) { + /* + * Reading. Any unread characters (including + * those from ungetc) cause the position to be + * smaller than that in the underlying object. + */ + if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) { + fp->_flags |= __SERR; + errno = EIO; + return (1); + } + if (HASUB(fp)) + pos -= fp->_r; /* Can be negative at this point. */ + } else if ((fp->_flags & __SWR) && fp->_p != NULL) { + /* + * Writing. Any buffered characters cause the + * position to be greater than that in the + * underlying object. + */ + n = fp->_p - fp->_bf._base; + if (pos > OFF_MAX - n) { + errno = EOVERFLOW; + return (1); + } + pos += n; + } + *offset = pos; + return (0); +} |