wint_t
__wunderflow (FILE *fp)
{
if (fp->_mode < 0 || (fp->_mode == 0 && _IO_fwide (fp, 1) != 1))
return WEOF;
if (fp->_mode == 0)
_IO_fwide (fp, 1);
if (_IO_in_put_mode (fp))
if (_IO_switch_to_wget_mode (fp) == EOF)
return WEOF;
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
return *fp->_wide_data->_IO_read_ptr;
if (_IO_in_backup (fp))
{
_IO_switch_to_main_wget_area (fp);
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
return *fp->_wide_data->_IO_read_ptr;
}
if (_IO_have_markers (fp))
{
if (save_for_wbackup (fp, fp->_wide_data->_IO_read_end))
return WEOF;
}
else if (_IO_have_backup (fp))
_IO_free_wbackup_area (fp);
return _IO_UNDERFLOW (fp);
}
void
_IO_init_wmarker (struct _IO_marker *marker, FILE *fp)
{
marker->_sbuf = fp;
if (_IO_in_put_mode (fp))
_IO_switch_to_wget_mode (fp);
if (_IO_in_backup (fp))
marker->_pos = fp->_wide_data->_IO_read_ptr - fp->_wide_data->_IO_read_end;
else
marker->_pos = (fp->_wide_data->_IO_read_ptr
- fp->_wide_data->_IO_read_base);
/* Should perhaps sort the chain? */
marker->_next = fp->_markers;
fp->_markers = marker;
}
_IO_off64_t
_IO_wfile_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode)
{
_IO_off64_t result;
_IO_off64_t delta, new_offset;
long int count;
/* Short-circuit into a separate function. We don't want to mix any
functionality and we don't want to touch anything inside the FILE
object. */
if (mode == 0)
return do_ftell_wide (fp);
/* POSIX.1 8.2.3.7 says that after a call the fflush() the file
offset of the underlying file must be exact. */
int must_be_exact = ((fp->_wide_data->_IO_read_base
== fp->_wide_data->_IO_read_end)
&& (fp->_wide_data->_IO_write_base
== fp->_wide_data->_IO_write_ptr));
bool was_writing = ((fp->_wide_data->_IO_write_ptr
> fp->_wide_data->_IO_write_base)
|| _IO_in_put_mode (fp));
/* Flush unwritten characters.
(This may do an unneeded write if we seek within the buffer.
But to be able to switch to reading, we would need to set
egptr to pptr. That can't be done in the current design,
which assumes file_ptr() is eGptr. Anyway, since we probably
end up flushing when we close(), it doesn't make much difference.)
FIXME: simulate mem-mapped files. */
if (was_writing && _IO_switch_to_wget_mode (fp))
return WEOF;
if (fp->_wide_data->_IO_buf_base == NULL)
{
/* It could be that we already have a pushback buffer. */
if (fp->_wide_data->_IO_read_base != NULL)
{
free (fp->_wide_data->_IO_read_base);
fp->_flags &= ~_IO_IN_BACKUP;
}
_IO_doallocbuf (fp);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
}
switch (dir)
{
struct _IO_codecvt *cv;
int clen;
case _IO_seek_cur:
/* Adjust for read-ahead (bytes is buffer). To do this we must
find out which position in the external buffer corresponds to
the current position in the internal buffer. */
cv = fp->_codecvt;
clen = (*cv->__codecvt_do_encoding) (cv);
if (mode != 0 || !was_writing)
{
if (clen > 0)
{
offset -= (fp->_wide_data->_IO_read_end
- fp->_wide_data->_IO_read_ptr) * clen;
/* Adjust by readahead in external buffer. */
offset -= fp->_IO_read_end - fp->_IO_read_ptr;
}
else
{
int nread;
delta = (fp->_wide_data->_IO_read_ptr
- fp->_wide_data->_IO_read_base);
fp->_wide_data->_IO_state = fp->_wide_data->_IO_last_state;
nread = (*cv->__codecvt_do_length) (cv,
&fp->_wide_data->_IO_state,
fp->_IO_read_base,
fp->_IO_read_end, delta);
fp->_IO_read_ptr = fp->_IO_read_base + nread;
fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_read_ptr;
offset -= fp->_IO_read_end - fp->_IO_read_base - nread;
}
}
if (fp->_offset == _IO_pos_BAD)
goto dumb;
/* Make offset absolute, assuming current pointer is file_ptr(). */
offset += fp->_offset;
dir = _IO_seek_set;
break;
case _IO_seek_set:
break;
case _IO_seek_end:
{
struct stat64 st;
if (_IO_SYSSTAT (fp, &st) == 0 && S_ISREG (st.st_mode))
{
offset += st.st_size;
dir = _IO_seek_set;
}
else
goto dumb;
}
}
/* At this point, dir==_IO_seek_set. */
/* If destination is within current buffer, optimize: */
if (fp->_offset != _IO_pos_BAD && fp->_IO_read_base != NULL
&& !_IO_in_backup (fp))
{
_IO_off64_t start_offset = (fp->_offset
- (fp->_IO_read_end - fp->_IO_buf_base));
if (offset >= start_offset && offset < fp->_offset)
{
_IO_setg (fp, fp->_IO_buf_base,
fp->_IO_buf_base + (offset - start_offset),
fp->_IO_read_end);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
if (adjust_wide_data (fp, false))
goto dumb;
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
goto resync;
}
}
if (fp->_flags & _IO_NO_READS)
goto dumb;
/* Try to seek to a block boundary, to improve kernel page management. */
new_offset = offset & ~(fp->_IO_buf_end - fp->_IO_buf_base - 1);
delta = offset - new_offset;
if (delta > fp->_IO_buf_end - fp->_IO_buf_base)
{
new_offset = offset;
delta = 0;
}
result = _IO_SYSSEEK (fp, new_offset, 0);
if (result < 0)
return EOF;
if (delta == 0)
count = 0;
else
{
count = _IO_SYSREAD (fp, fp->_IO_buf_base,
(must_be_exact
? delta : fp->_IO_buf_end - fp->_IO_buf_base));
if (count < delta)
{
/* We weren't allowed to read, but try to seek the remainder. */
offset = count == EOF ? delta : delta-count;
dir = _IO_seek_cur;
goto dumb;
}
}
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base + delta,
fp->_IO_buf_base + count);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
if (adjust_wide_data (fp, true))
goto dumb;
fp->_offset = result + count;
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
return offset;
dumb:
_IO_unsave_markers (fp);
result = _IO_SYSSEEK (fp, offset, dir);
if (result != EOF)
{
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
fp->_offset = result;
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
}
return result;
resync:
/* We need to do it since it is possible that the file offset in
the kernel may be changed behind our back. It may happen when
we fopen a file and then do a fork. One process may access the
file and the kernel file offset will be changed. */
if (fp->_offset >= 0)
_IO_SYSSEEK (fp, fp->_offset, 0);
return offset;
}
