wget/lib/freading.c

77 lines
3.1 KiB
C

/* Retrieve information about a FILE stream.
Copyright (C) 2007-2023 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 "freading.h"
#include "stdio-impl.h"
/* Don't use glibc's __freading function in glibc < 2.7, see
<https://sourceware.org/bugzilla/show_bug.cgi?id=4359> */
#if !(HAVE___FREADING && (!defined __GLIBC__ || defined __UCLIBC__ || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7)))
bool
freading (FILE *fp)
{
/* 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 */
return ((fp->_flags & _IO_NO_WRITES) != 0
|| ((fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
&& fp->_IO_read_base != NULL));
# elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */
return (fp_->_flags & __SRD) != 0;
# elif defined __EMX__ /* emx+gcc */
return (fp->_flags & _IOREAD) != 0;
# elif defined __minix /* Minix */
return (fp->_flags & _IOREADING) != 0;
# elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
# if defined __sun /* Solaris */
return (fp_->_flag & _IOREAD) != 0 && (fp_->_flag & _IOWRT) == 0;
# else
return (fp_->_flag & _IOREAD) != 0;
# endif
# elif defined __UCLIBC__ /* uClibc */
return (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) != 0;
# elif defined __QNX__ /* QNX */
return ((fp->_Mode & 0x2 /* _MOPENW */) == 0
|| (fp->_Mode & 0x1000 /* _MREAD */) != 0);
# elif defined __MINT__ /* Atari FreeMiNT */
if (!fp->__mode.__write)
return 1;
if (!fp->__mode.__read)
return 0;
# ifdef _IO_CURRENTLY_GETTING /* Flag added on 2009-02-28 */
return (fp->__flags & _IO_CURRENTLY_GETTING) != 0;
# else
return (fp->__buffer < fp->__get_limit /*|| fp->__bufp == fp->__put_limit ??*/);
# endif
# elif defined EPLAN9 /* Plan9 */
if (fp->state == 0 /* CLOSED */ || fp->state == 4 /* WR */)
return 0;
return (fp->state == 3 /* RD */ && (fp->bufl == 0 || fp->rp < fp->wp));
# else
# error "Please port gnulib freading.c to your platform!"
# endif
}
#endif