diff options
Diffstat (limited to 'mit-pthreads/stdio/fseek.c')
| -rw-r--r-- | mit-pthreads/stdio/fseek.c | 248 |
1 files changed, 0 insertions, 248 deletions
diff --git a/mit-pthreads/stdio/fseek.c b/mit-pthreads/stdio/fseek.c deleted file mode 100644 index 5c7feda638f..00000000000 --- a/mit-pthreads/stdio/fseek.c +++ /dev/null @@ -1,248 +0,0 @@ -/*- - * Copyright (c) 1990 The Regents of the University of California. - * Copyright (c) 1993, 1994 Chris Provenzano. - * 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 = "from: @(#)fseek.c 5.7 (Berkeley) 2/24/91";*/ -static char *rcsid = "$Id$"; -#endif /* LIBC_SCCS and not lint */ - -#include <pthread.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) - -/* - * Seek the given file to the given offset. - * `Whence' must be one of the three SEEK_* macros. - */ -fseek(fp, offset, whence) - register FILE *fp; - long offset; - int whence; -{ -#if __STDC__ - register fpos_t (*seekfn)(void *, fpos_t, int); -#else - register fpos_t (*seekfn)(); -#endif - fpos_t target, curoff; - size_t n; - struct stat st; - int havepos; - - /* make sure stdio is set up */ - __sinit (); - - flockfile(fp); - - /* - * 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 = __sseek(fp, (off_t)0, SEEK_CUR); - if (curoff == -1L) { - 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 (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 = __sseek(fp, (off_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)) { - 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 fgetline.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 (__sseek(fp, (off_t)curoff, SEEK_SET) != POS_ERR) { - 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) || __sseek(fp, (off_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); -} |