diff options
author | Jeff Johnston <jjohnstn@redhat.com> | 2006-12-15 01:47:12 +0300 |
---|---|---|
committer | Jeff Johnston <jjohnstn@redhat.com> | 2006-12-15 01:47:12 +0300 |
commit | 4c0b8a072bc2877282383f799274361858ff1c3e (patch) | |
tree | 09a22f55da3a75d23c9fadb25e2df8243e477cd2 /newlib/libc/stdio | |
parent | 6a20095878bec4a4d262b0d027a10f269248d527 (diff) |
2006-12-14 Jeff Johnston <jjohnstn@redhat.com>
Eric Blake <ebb9@byu.net>
* libc/stdio/fflush.c (fflush): On seekable streams, always flush
read but unused data.
* libc/stdio/fclose.c (_fclose_r): Always flush streams, since
even read streams may have side effects that must happen.
Diffstat (limited to 'newlib/libc/stdio')
-rw-r--r-- | newlib/libc/stdio/fclose.c | 5 | ||||
-rw-r--r-- | newlib/libc/stdio/fflush.c | 48 |
2 files changed, 51 insertions, 2 deletions
diff --git a/newlib/libc/stdio/fclose.c b/newlib/libc/stdio/fclose.c index bb3acb624..08df75fb4 100644 --- a/newlib/libc/stdio/fclose.c +++ b/newlib/libc/stdio/fclose.c @@ -86,7 +86,10 @@ _DEFUN(_fclose_r, (rptr, fp), __sfp_lock_release (); return (0); } - r = fp->_flags & __SWR ? fflush (fp) : 0; + /* Unconditionally flush to allow special handling for seekable read + files to reposition file to last byte processed as opposed to + last byte read ahead into the buffer. */ + r = fflush (fp); if (fp->_close != NULL && (*fp->_close) (fp->_cookie) < 0) r = EOF; if (fp->_flags & __SMBF) diff --git a/newlib/libc/stdio/fflush.c b/newlib/libc/stdio/fflush.c index bac49804f..a8ef755c2 100644 --- a/newlib/libc/stdio/fflush.c +++ b/newlib/libc/stdio/fflush.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 1990 The Regents of the University of California. + * Copyright (c) 1990, 2006 The Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms are permitted @@ -74,10 +74,56 @@ _DEFUN(fflush, (fp), t = fp->_flags; if ((t & __SWR) == 0) { + _fpos_t _EXFUN((*seekfn), (_PTR, _fpos_t, int)); + /* For a read stream, an fflush causes the next seek to be unoptimized (i.e. forces a system-level seek). This conforms to the POSIX and SUSv3 standards. */ fp->_flags |= __SNPT; + + /* For a seekable stream with buffered read characters, we will attempt + a seek to the current position now. A subsequent read will then get + the next byte from the file rather than the buffer. This conforms + to the POSIX and SUSv3 standards. Note that the standards allow + this seek to be deferred until necessary, but we choose to do it here + to make the change simpler, more contained, and less likely + to miss a code scenario. */ + if ((fp->_r > 0 || fp->_ur > 0) && (seekfn = fp->_seek) != NULL) + { + _fpos_t curoff; + + /* Get the physical position we are at in the file. */ + if (fp->_flags & __SOFF) + curoff = fp->_offset; + else + { + /* We don't know current physical offset, so ask for it. */ + curoff = (*seekfn) (fp->_cookie, (_fpos_t) 0, SEEK_CUR); + if (curoff == -1L) + { + _funlockfile (fp); + return 0; + } + } + if (fp->_flags & __SRD) + { + /* Current offset is at end of buffer. Compensate for + characters not yet read. */ + curoff -= fp->_r; + if (HASUB (fp)) + curoff -= fp->_ur; + } + /* Now physically seek to after byte last read. */ + if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) != -1) + { + /* Seek successful. We can clear read buffer now. */ + fp->_flags &= ~__SNPT; + fp->_r = 0; + fp->_p = fp->_bf._base; + if (fp->_flags & __SOFF) + fp->_offset = curoff; + } + } _funlockfile (fp); return 0; } |