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author | rgrimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
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committer | rgrimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
commit | be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da (patch) | |
tree | a18a706dffa5baf86a3b12bbfb4f81caa097f349 /lib/libc/stdio/ftell.c | |
parent | 2a27bd86e6002c871e3b5561a5334653bb222a77 (diff) | |
download | FreeBSD-src-be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da.zip FreeBSD-src-be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da.tar.gz |
BSD 4.4 Lite Lib Sources
Diffstat (limited to 'lib/libc/stdio/ftell.c')
-rw-r--r-- | lib/libc/stdio/ftell.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/lib/libc/stdio/ftell.c b/lib/libc/stdio/ftell.c new file mode 100644 index 0000000..724e543 --- /dev/null +++ b/lib/libc/stdio/ftell.c @@ -0,0 +1,88 @@ +/*- + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 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 8.1 (Berkeley) 6/4/93"; +#endif /* LIBC_SCCS and not lint */ + +#include <stdio.h> +#include <errno.h> +#include "local.h" + +/* + * ftell: return current offset. + */ +long +ftell(fp) + register const FILE *fp; +{ + register fpos_t pos; + + if (fp->_seek == NULL) { + errno = ESPIPE; /* historic practice */ + return (-1L); + } + + /* + * Find offset of underlying I/O object, then + * adjust for buffered bytes. + */ + if (fp->_flags & __SOFF) + pos = fp->_offset; + else { + pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR); + if (pos == -1L) + return (pos); + } + if (fp->_flags & __SRD) { + /* + * Reading. Any unread characters (including + * those from ungetc) cause the position to be + * smaller than that in the underlying object. + */ + pos -= fp->_r; + if (HASUB(fp)) + pos -= fp->_ur; + } else if (fp->_flags & __SWR && fp->_p != NULL) { + /* + * Writing. Any buffered characters cause the + * position to be greater than that in the + * underlying object. + */ + pos += fp->_p - fp->_bf._base; + } + return (pos); +} |