diff options
Diffstat (limited to 'lib/fflush.c')
| -rw-r--r-- | lib/fflush.c | 218 |
1 files changed, 0 insertions, 218 deletions
diff --git a/lib/fflush.c b/lib/fflush.c deleted file mode 100644 index f90ba6fa1..000000000 --- a/lib/fflush.c +++ /dev/null @@ -1,218 +0,0 @@ -/* fflush.c -- allow flushing input streams - Copyright (C) 2007-2011 Free Software Foundation, Inc. - - This program 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 3 of the License, or - (at your option) any later version. - - This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */ - -/* Written by Eric Blake. */ - -#include <config.h> - -/* Specification. */ -#include <stdio.h> - -#include <errno.h> -#include <unistd.h> - -#include "freading.h" - -#include "stdio-impl.h" - -#undef fflush - - -#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */ - -/* Clear the stream's ungetc buffer, preserving the value of ftello (fp). */ -static inline void -clear_ungetc_buffer_preserving_position (FILE *fp) -{ - if (fp->_flags & _IO_IN_BACKUP) - /* _IO_free_backup_area is a bit complicated. Simply call fseek. */ - fseeko (fp, 0, SEEK_CUR); -} - -#else - -/* Clear the stream's ungetc buffer. May modify the value of ftello (fp). */ -static inline void -clear_ungetc_buffer (FILE *fp) -{ -# if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ - if (HASUB (fp)) - { - fp_->_p += fp_->_r; - fp_->_r = 0; - } -# elif defined __EMX__ /* emx+gcc */ - if (fp->_ungetc_count > 0) - { - fp->_ungetc_count = 0; - fp->_rcount = - fp->_rcount; - } -# elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw, NonStop Kernel */ - /* Nothing to do. */ -# else /* other implementations */ - fseeko (fp, 0, SEEK_CUR); -# endif -} - -#endif - -#if (defined __sferror || defined __DragonFly__) && defined __SNPT /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ - -static inline int -disable_seek_optimization (FILE *fp) -{ - int saved_flags = fp_->_flags & (__SOPT | __SNPT); - fp_->_flags = (fp_->_flags & ~__SOPT) | __SNPT; - return saved_flags; -} - -static inline void -restore_seek_optimization (FILE *fp, int saved_flags) -{ - fp_->_flags = (fp_->_flags & ~(__SOPT | __SNPT)) | saved_flags; -} - -#endif - -static inline void -update_fpos_cache (FILE *fp, off_t pos) -{ -#if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ -# if defined __CYGWIN__ - /* fp_->_offset is typed as an integer. */ - fp_->_offset = pos; -# else - /* fp_->_offset is an fpos_t. */ - /* Use a union, since on NetBSD, the compilation flags determine - whether fpos_t is typedef'd to off_t or a struct containing a - single off_t member. */ - union - { - fpos_t f; - off_t o; - } u; - u.o = pos; - fp_->_offset = u.f; -# endif - fp_->_flags |= __SOFF; -#endif -} - -/* Flush all pending data on STREAM according to POSIX rules. Both - output and seekable input streams are supported. */ -int -rpl_fflush (FILE *stream) -{ - /* When stream is NULL, POSIX and C99 only require flushing of "output - streams and update streams in which the most recent operation was not - input", and all implementations do this. - - When stream is "an output stream or an update stream in which the most - recent operation was not input", POSIX and C99 requires that fflush - writes out any buffered data, and all implementations do this. - - When stream is, however, an input stream or an update stream in - which the most recent operation was input, C99 specifies nothing, - and POSIX only specifies behavior if the stream is seekable. - mingw, in particular, drops the input buffer, leaving the file - descriptor positioned at the end of the input buffer. I.e. ftell - (stream) is lost. We don't want to call the implementation's - fflush in this case. - - We test ! freading (stream) here, rather than fwriting (stream), because - what we need to know is whether the stream holds a "read buffer", and on - mingw this is indicated by _IOREAD, regardless of _IOWRT. */ - if (stream == NULL || ! freading (stream)) - return fflush (stream); - -#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */ - - clear_ungetc_buffer_preserving_position (stream); - - return fflush (stream); - -#else - { - /* Notes about the file-position indicator: - 1) The file position indicator is incremented by fgetc() and decremented - by ungetc(): - <http://www.opengroup.org/susv3/functions/fgetc.html> - "... the fgetc() function shall ... advance the associated file - position indicator for the stream ..." - <http://www.opengroup.org/susv3/functions/ungetc.html> - "The file-position indicator is decremented by each successful - call to ungetc()..." - 2) <http://www.opengroup.org/susv3/functions/ungetc.html> says: - "The value of the file-position indicator for the stream after - reading or discarding all pushed-back bytes shall be the same - as it was before the bytes were pushed back." - Here we are discarding all pushed-back bytes. But more specifically, - 3) <http://www.opengroup.org/austin/aardvark/latest/xshbug3.txt> says: - "[After fflush(),] the file offset of the underlying open file - description shall be set to the file position of the stream, and - any characters pushed back onto the stream by ungetc() ... shall - be discarded." */ - - /* POSIX does not specify fflush behavior for non-seekable input - streams. Some implementations purge unread data, some return - EBADF, some do nothing. */ - off_t pos = ftello (stream); - if (pos == -1) - { - errno = EBADF; - return EOF; - } - - /* Clear the ungetc buffer. */ - clear_ungetc_buffer (stream); - - /* To get here, we must be flushing a seekable input stream, so the - semantics of fpurge are now appropriate to clear the buffer. To - avoid losing data, the lseek is also necessary. */ - { - int result = fpurge (stream); - if (result != 0) - return result; - } - -# if (defined __sferror || defined __DragonFly__) && defined __SNPT /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ - - { - /* Disable seek optimization for the next fseeko call. This tells the - following fseeko call to seek to the desired position directly, rather - than to seek to a block-aligned boundary. */ - int saved_flags = disable_seek_optimization (stream); - int result = fseeko (stream, pos, SEEK_SET); - - restore_seek_optimization (stream, saved_flags); - return result; - } - -# else - - pos = lseek (fileno (stream), pos, SEEK_SET); - if (pos == -1) - return EOF; - /* After a successful lseek, update the file descriptor's position cache - in the stream. */ - update_fpos_cache (stream, pos); - - return 0; - -# endif - } -#endif -} |