diff options
Diffstat (limited to 'stdio/fseek.c')
| -rw-r--r-- | stdio/fseek.c | 179 |
1 files changed, 0 insertions, 179 deletions
diff --git a/stdio/fseek.c b/stdio/fseek.c deleted file mode 100644 index fb2e580fd0..0000000000 --- a/stdio/fseek.c +++ /dev/null @@ -1,179 +0,0 @@ -/* Copyright (C) 1991, 92, 93, 95, 96, 97 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, write to the Free - Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA - 02111-1307 USA. */ - -#include <errno.h> -#include <stdio.h> - - -/* Move the file position of STREAM to OFFSET - bytes from the beginning of the file if WHENCE - is SEEK_SET, the end of the file is it is SEEK_END, - or the current position if it is SEEK_CUR. */ -int -fseek (stream, offset, whence) - register FILE *stream; - long int offset; - int whence; -{ - long int o; - - if (!__validfp (stream)) - { - __set_errno (EINVAL); - return EOF; - } - - /* Write out any pending data. */ - if (stream->__mode.__write && __flshfp (stream, EOF) == EOF) - return EOF; - - /* Make sure we know the current offset info. */ - stream->__offset = -1; - if (__stdio_check_offset (stream) == EOF) - return EOF; - - /* We are moving the file position, so we are no longer at EOF. */ - stream->__eof = 0; - - if (stream->__pushed_back) - { - /* Discard the character pushed back by ungetc. */ - stream->__bufp = stream->__pushback_bufp; - stream->__pushed_back = 0; - } - - /* Check the WHENCE argument for validity, and process OFFSET - into an absolute position in O. By the end of this switch, - either we have returned, or O contains an absolute position. */ - o = offset; - switch (whence) - { - default: - __set_errno (EINVAL); - return EOF; - - case SEEK_END: - /* We don't know where the end of the file is, - so seek to the position in the file the user asked - for, and then look where that is. */ - if (stream->__io_funcs.__seek == NULL) - { - __set_errno (ESPIPE); - return EOF; - } - else - { - fpos_t pos = (fpos_t) o; - if ((*stream->__io_funcs.__seek) - (stream->__cookie, &pos, SEEK_END) < 0) - { - if (errno == ESPIPE) - stream->__io_funcs.__seek = NULL; - return EOF; - } - stream->__offset = pos; - /* Make O be absolute, rather than - relative to the end of the file. */ - o = pos; - } - - /* Fall through to try an absolute seek. */ - - case SEEK_SET: - /* Make O be relative to the buffer. */ - o -= stream->__target; - /* Make O be relative to the current position in the buffer. */ - o -= stream->__bufp - stream->__buffer; - - /* Fall through to see if we can do it by - moving the pointer around in the buffer. */ - - case SEEK_CUR: - /* If the offset is small enough, we can just - move the pointer around in the buffer. */ - -#if 0 /* Why did I think this would ever work??? */ - if (stream->__put_limit > stream->__buffer) - { - /* We are writing. */ - if (stream->__bufp + o >= stream->__buffer && - stream->__put_limit > stream->__bufp + o && - stream->__get_limit > stream->__bufp + o) - { - /* We have read all the data we will change soon. - We can just move the pointer around. */ - stream->__bufp += o; - return 0; - } - else - { - /* Flush the buffer. */ - if (__flshfp(stream, EOF) == EOF) - return EOF; - } - } else -#endif - if (o < 0 ? - (-o <= stream->__bufp - stream->__buffer) : - (o <= stream->__get_limit - stream->__bufp)) - { - stream->__bufp += o; - return 0; - } - - /* Turn it into an absolute seek. */ - o += stream->__bufp - stream->__buffer; - o += stream->__target; - break; - } - - if (o < 0) - { - /* Negative file position is meaningless. */ - __set_errno (EINVAL); - return -1; - } - - /* O is now an absolute position, the new target. */ - stream->__target = o; - - /* Set bufp and both end pointers to the beginning of the buffer. - The next i/o will force a call to the input/output room function. */ - stream->__bufp - = stream->__get_limit = stream->__put_limit = stream->__buffer; - - /* Make sure __flshfp doesn't think the put_limit is at the beginning - of the buffer because of line-buffering magic. */ - stream->__linebuf_active = 0; - - /* If there is no seek function, seeks always fail. */ - if (stream->__io_funcs.__seek == NULL) - { - /* This is preemptive, since we don't actually do the seeking. - But it makes more sense for fseek to to fail with ESPIPE - than for the next reading or writing operation to fail - that way. */ - __set_errno (ESPIPE); - return EOF; - } - - /* Don't actually seek. The next reading or writing operation - will force a call to the input or output room function, - which will move to the target file position before reading or writing. */ - return 0; -} |