rm_/lib/fpurge.c
2022-07-28 14:16:50 +08:00

151 lines
5.1 KiB
C

/* Flushing buffers of a FILE stream.
Copyright (C) 2007-2022 Free Software Foundation, Inc.
This file 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.
This file 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 <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include <stdio.h>
#if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
# if HAVE_STDIO_EXT_H
# include <stdio_ext.h>
# endif
#endif
#include <stdlib.h>
#include "stdio-impl.h"
int
fpurge (FILE *fp)
{
#if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
__fpurge (fp);
/* The __fpurge function does not have a return value. */
return 0;
#elif HAVE_FPURGE /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin >= 1.7 */
/* Call the system's fpurge function. */
# undef fpurge
# if !HAVE_DECL_FPURGE
extern int fpurge (FILE *);
# endif
int result = fpurge (fp);
# if defined __sferror || defined __DragonFly__ || defined __ANDROID__
/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
if (result == 0)
/* Correct the invariants that fpurge broke.
<stdio.h> on BSD systems says:
"The following always hold: if _flags & __SRD, _w is 0."
If this invariant is not fulfilled and the stream is read-write but
currently reading, subsequent putc or fputc calls will write directly
into the buffer, although they shouldn't be allowed to. */
if ((fp_->_flags & __SRD) != 0)
fp_->_w = 0;
# endif
return result;
#else
/* Most systems provide FILE as a struct and the necessary bitmask in
<stdio.h>, because they need it for implementing getc() and putc() as
fast macros. */
# if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
/* GNU libc, BeOS, Haiku, Linux libc5 */
fp->_IO_read_end = fp->_IO_read_ptr;
fp->_IO_write_ptr = fp->_IO_write_base;
/* Avoid memory leak when there is an active ungetc buffer. */
if (fp->_IO_save_base != NULL)
{
free (fp->_IO_save_base);
fp->_IO_save_base = NULL;
}
return 0;
# elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
fp_->_p = fp_->_bf._base;
fp_->_r = 0;
fp_->_w = ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
? fp_->_bf._size
: 0);
/* Avoid memory leak when there is an active ungetc buffer. */
if (fp_ub._base != NULL)
{
if (fp_ub._base != fp_->_ubuf)
free (fp_ub._base);
fp_ub._base = NULL;
}
return 0;
# elif defined __EMX__ /* emx+gcc */
fp->_ptr = fp->_buffer;
fp->_rcount = 0;
fp->_wcount = 0;
fp->_ungetc_count = 0;
return 0;
# elif defined __minix /* Minix */
fp->_ptr = fp->_buf;
if (fp->_ptr != NULL)
fp->_count = 0;
return 0;
# elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
fp_->_ptr = fp_->_base;
if (fp_->_ptr != NULL)
fp_->_cnt = 0;
return 0;
# elif defined __UCLIBC__ /* uClibc */
# ifdef __STDIO_BUFFERS
if (fp->__modeflags & __FLAG_WRITING)
fp->__bufpos = fp->__bufstart;
else if (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING))
fp->__bufpos = fp->__bufread;
# endif
return 0;
# elif defined __QNX__ /* QNX */
fp->_Rback = fp->_Back + sizeof (fp->_Back);
fp->_Rsave = NULL;
if (fp->_Mode & 0x2000 /* _MWRITE */)
/* fp->_Buf <= fp->_Next <= fp->_Wend */
fp->_Next = fp->_Buf;
else
/* fp->_Buf <= fp->_Next <= fp->_Rend */
fp->_Rend = fp->_Next;
return 0;
# elif defined __MINT__ /* Atari FreeMiNT */
if (fp->__pushed_back)
{
fp->__bufp = fp->__pushback_bufp;
fp->__pushed_back = 0;
}
/* Preserve the current file position. */
if (fp->__target != -1)
fp->__target += fp->__bufp - fp->__buffer;
fp->__bufp = fp->__buffer;
/* Nothing in the buffer, next getc is nontrivial. */
fp->__get_limit = fp->__bufp;
/* Nothing in the buffer, next putc is nontrivial. */
fp->__put_limit = fp->__buffer;
return 0;
# elif defined EPLAN9 /* Plan9 */
fp->rp = fp->wp = fp->lp = fp->buf;
return 0;
# else
# error "Please port gnulib fpurge.c to your platform! Look at the definitions of fflush, setvbuf and ungetc on your system, then report this to bug-gnulib."
# endif
#endif
}