/***
*ftelli64.c - get current file position
*
* Copyright (c) 1994-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _ftelli64() - find current current position of file pointer
*
*Revision History:
* 12-22-94 GJF Module created. Derived from ftell.c
* 02-06-94 CFW assert -> _ASSERTE.
* 03-07-95 GJF _[un]lock_str macros now take FILE * arg.
* 06-23-95 GJF Replaced _osfile[] with _osfile() (macro referencing
* field in ioinfo struct).
* 03-02-98 GJF Exception-safe locking.
* 03-04-98 RKP Added 64 bit support.
*
*******************************************************************************/
#include <cruntime.h>
#include <stdio.h>
#include <file2.h>
#include <dbgint.h>
#include <errno.h>
#include <msdos.h>
#include <stddef.h>
#include <io.h>
#include <internal.h>
#include <mtdll.h>
/***
*__int64 _ftelli64(stream) - query stream file pointer
*
*Purpose:
* Find out what stream's position is. coordinate with buffering; adjust
* backward for read-ahead and forward for write-behind. This is NOT
* equivalent to fseek(stream,0L,1), because fseek will remove an ungetc,
* may flush buffers, etc.
*
*Entry:
* FILE *stream - stream to query for position
*
*Exit:
* return present file position if succeeds
* returns -1i64 and sets errno if fails
*
*Exceptions:
*
*******************************************************************************/
#ifdef _MT
__int64 __cdecl _ftelli64 (
FILE *stream
)
{
__int64 retval;
_ASSERTE(stream != NULL);
_lock_str(stream);
__try {
retval = _ftelli64_lk (stream);
}
__finally {
_unlock_str(stream);
}
return(retval);
}
/***
*_ftelli64_lk() - _ftelli64() core routine (assumes stream is locked).
*
*Purpose:
* Core _ftelli64() routine (assumes caller has aquired stream lock).
*
*Entry:
*
*Exit:
*
*Exceptions:
*
*******************************************************************************/
__int64 __cdecl _ftelli64_lk (
#else /* mdef _MT */
__int64 __cdecl _ftelli64 (
#endif /* _MT */
FILE *str
)
{
REG1 FILE *stream;
size_t offset;
__int64 filepos;
REG2 char *p;
char *max;
int fd;
size_t rdcnt;
_ASSERTE(str != NULL);
/* Init stream pointer and file descriptor */
stream = str;
fd = _fileno(stream);
if (stream->_cnt < 0)
stream->_cnt = 0;
if ((filepos = _lseeki64(fd, 0i64, SEEK_CUR)) < 0L)
return(-1i64);
if (!bigbuf(stream)) /* _IONBF or no buffering designated */
return(filepos - stream->_cnt);
offset = (size_t)(stream->_ptr - stream->_base);
if (stream->_flag & (_IOWRT|_IOREAD)) {
if (_osfile(fd) & FTEXT)
for (p = stream->_base; p < stream->_ptr; p++)
if (*p == '\n') /* adjust for '\r' */
offset++;
}
else if (!(stream->_flag & _IORW)) {
errno=EINVAL;
return(-1i64);
}
if (filepos == 0i64)
return((__int64)offset);
if (stream->_flag & _IOREAD) /* go to preceding sector */
if (stream->_cnt == 0) /* filepos holds correct location */
offset = 0;
else {
/* Subtract out the number of unread bytes left in the
buffer. [We can't simply use _iob[]._bufsiz because
the last read may have hit EOF and, thus, the buffer
was not completely filled.] */
rdcnt = stream->_cnt + (size_t)(stream->_ptr - stream->_base);
/* If text mode, adjust for the cr/lf substitution. If
binary mode, we're outta here. */
if (_osfile(fd) & FTEXT) {
/* (1) If we're not at eof, simply copy _bufsiz
onto rdcnt to get the # of untranslated
chars read. (2) If we're at eof, we must
look through the buffer expanding the '\n'
chars one at a time. */
/* [NOTE: Performance issue -- it is faster to
do the two _lseek() calls than to blindly go
through and expand the '\n' chars regardless
of whether we're at eof or not.] */
if (_lseeki64(fd, 0i64, SEEK_END) == filepos) {
max = stream->_base + rdcnt;
for (p = stream->_base; p < max; p++)
if (*p == '\n')
/* adjust for '\r' */
rdcnt++;
/* If last byte was ^Z, the lowio read
didn't tell us about it. Check flag
and bump count, if necessary. */
if (stream->_flag & _IOCTRLZ)
++rdcnt;
}
else {
_lseeki64(fd, filepos, SEEK_SET);
/* We want to set rdcnt to the number
of bytes originally read into the
stream buffer (before crlf->lf
translation). In most cases, this
will just be _bufsiz. However, the
buffer size may have been changed,
due to fseek optimization, at the
END of the last _filbuf call. */
if ( (rdcnt <= _SMALL_BUFSIZ) &&
(stream->_flag & _IOMYBUF) &&
!(stream->_flag & _IOSETVBUF) )
{
/* The translated contents of
the buffer is small and we
are not at eof. The buffer
size must have been set to
_SMALL_BUFSIZ during the
last _filbuf call. */
rdcnt = _SMALL_BUFSIZ;
}
else
rdcnt = stream->_bufsiz;
/* If first byte in untranslated buffer
was a '\n', assume it was preceeded
by a '\r' which was discarded by the
previous read operation and count
the '\n'. */
if (_osfile(fd) & FCRLF)
++rdcnt;
}
} /* end if FTEXT */
filepos -= (__int64)rdcnt;
} /* end else stream->_cnt != 0 */
return(filepos + (__int64)offset);
}