+++ /dev/null
-/*
- * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-/*
- * 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.
- */
-
-
-#include <sys/types.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <errno.h>
-#include "local.h"
-
-#define POS_ERR (-(fpos_t)1)
-
-int
-fseek(fp, offset, whence)
- register FILE *fp;
- long offset;
- int whence;
-{
- return (fseeko(fp, offset, whence));
-}
-
-
-/*
- * Seek the given file to the given offset.
- * `Whence' must be one of the three SEEK_* macros.
- */
-int
-fseeko(fp, offset, whence)
- register FILE *fp;
- off_t offset;
- int whence;
-{
- register fpos_t (*seekfn) __P((void *, fpos_t, int));
- fpos_t target, curoff;
- size_t n;
- struct stat st;
- int havepos;
-
- /* make sure stdio is set up */
- if (!__sdidinit)
- __sinit();
-
- /* FLOCKFILE(fp); */
- /*
- * Have to be able to seek.
- */
- if ((seekfn = fp->_seek) == NULL) {
- errno = ESPIPE; /* historic practice */
- /* FUNLOCKFILE(fp); */
- return (EOF);
- }
-
- /*
- * Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
- * After this, whence is either SEEK_SET or SEEK_END.
- */
- switch (whence) {
-
- case SEEK_CUR:
- /*
- * In order to seek relative to the current stream offset,
- * we have to first find the current stream offset a la
- * ftell (see ftell for details).
- */
- if (fp->_flags & __SOFF)
- curoff = fp->_offset;
- else {
- curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
- if (curoff == -1) {
- /* FUNLOCKFILE(fp); */
- return (EOF);
- }
- }
- if (fp->_flags & __SRD) {
- curoff -= fp->_r;
- if (HASUB(fp))
- curoff -= fp->_ur;
- } else if (fp->_flags & __SWR && fp->_p != NULL)
- curoff += fp->_p - fp->_bf._base;
-
- offset += curoff;
- whence = SEEK_SET;
- havepos = 1;
- break;
-
- case SEEK_SET:
- case SEEK_END:
- curoff = 0; /* XXX just to keep gcc quiet */
- havepos = 0;
- break;
-
- default:
- errno = EINVAL;
- /* FUNLOCKFILE(fp); */
- return (EOF);
- }
-
- /*
- * Can only optimise if:
- * reading (and not reading-and-writing);
- * not unbuffered; and
- * this is a `regular' Unix file (and hence seekfn==__sseek).
- * We must check __NBF first, because it is possible to have __NBF
- * and __SOPT both set.
- */
- if (fp->_bf._base == NULL)
- __smakebuf(fp);
- if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
- goto dumb;
- if ((fp->_flags & __SOPT) == 0) {
- if (seekfn != __sseek ||
- fp->_file < 0 || fstat(fp->_file, &st) ||
- (st.st_mode & S_IFMT) != S_IFREG) {
- fp->_flags |= __SNPT;
- goto dumb;
- }
- fp->_blksize = st.st_blksize;
- fp->_flags |= __SOPT;
- }
-
- /*
- * We are reading; we can try to optimise.
- * Figure out where we are going and where we are now.
- */
- if (whence == SEEK_SET)
- target = offset;
- else {
- if (fstat(fp->_file, &st))
- goto dumb;
- target = st.st_size + offset;
- }
-
- if (!havepos) {
- if (fp->_flags & __SOFF)
- curoff = fp->_offset;
- else {
- curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
- if (curoff == POS_ERR)
- goto dumb;
- }
- curoff -= fp->_r;
- if (HASUB(fp))
- curoff -= fp->_ur;
- }
-
- /*
- * Compute the number of bytes in the input buffer (pretending
- * that any ungetc() input has been discarded). Adjust current
- * offset backwards by this count so that it represents the
- * file offset for the first byte in the current input buffer.
- */
- if (HASUB(fp)) {
- curoff += fp->_r; /* kill off ungetc */
- n = fp->_up - fp->_bf._base;
- curoff -= n;
- n += fp->_ur;
- } else {
- n = fp->_p - fp->_bf._base;
- curoff -= n;
- n += fp->_r;
- }
-
- /*
- * If the target offset is within the current buffer,
- * simply adjust the pointers, clear EOF, undo ungetc(),
- * and return. (If the buffer was modified, we have to
- * skip this; see fgetln.c.)
- */
- if ((fp->_flags & __SMOD) == 0 &&
- target >= curoff && target < curoff + n) {
- register int o = target - curoff;
-
- fp->_p = fp->_bf._base + o;
- fp->_r = n - o;
- if (HASUB(fp))
- FREEUB(fp);
- fp->_flags &= ~__SEOF;
- /* FUNLOCKFILE(fp); */
- return (0);
- }
-
- /*
- * The place we want to get to is not within the current buffer,
- * but we can still be kind to the kernel copyout mechanism.
- * By aligning the file offset to a block boundary, we can let
- * the kernel use the VM hardware to map pages instead of
- * copying bytes laboriously. Using a block boundary also
- * ensures that we only read one block, rather than two.
- */
- curoff = target & ~(fp->_blksize - 1);
- if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)
- goto dumb;
- fp->_r = 0;
- fp->_p = fp->_bf._base;
- if (HASUB(fp))
- FREEUB(fp);
- fp->_flags &= ~__SEOF;
- n = target - curoff;
- if (n) {
- if (__srefill(fp) || fp->_r < n)
- goto dumb;
- fp->_p += n;
- fp->_r -= n;
- }
- /* FUNLOCKFILE(fp); */
- return (0);
-
- /*
- * We get here if we cannot optimise the seek ... just
- * do it. Allow the seek function to change fp->_bf._base.
- */
-dumb:
- if (__sflush(fp) ||
- (*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR) {
- /* FUNLOCKFILE(fp); */
- return (EOF);
- }
- /* success: clear EOF indicator and discard ungetc() data */
- if (HASUB(fp))
- FREEUB(fp);
- fp->_p = fp->_bf._base;
- fp->_r = 0;
- /* fp->_w = 0; */ /* unnecessary (I think...) */
- fp->_flags &= ~__SEOF;
- /* FUNLOCKFILE(fp); */
- return (0);
-}
projects / apple / libc.git / blobdiff