| 1 | /* Retrieve information about a FILE stream.
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| 2 | Copyright (C) 2007-2022 Free Software Foundation, Inc.
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| 3 |
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| 4 | This file is free software: you can redistribute it and/or modify
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| 5 | it under the terms of the GNU Lesser General Public License as
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| 6 | published by the Free Software Foundation; either version 2.1 of the
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| 7 | License, or (at your option) any later version.
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| 8 |
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| 9 | This file is distributed in the hope that it will be useful,
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 12 | GNU Lesser General Public License for more details.
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| 13 |
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| 14 | You should have received a copy of the GNU Lesser General Public License
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| 15 | along with this program. If not, see <https://www.gnu.org/licenses/>. */
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| 16 |
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| 17 | #include <config.h>
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| 18 |
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| 19 | /* Specification. */
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| 20 | #include "freading.h"
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| 21 |
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| 22 | #include "stdio-impl.h"
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| 23 |
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| 24 | /* Don't use glibc's __freading function in glibc < 2.7, see
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| 25 | <https://sourceware.org/bugzilla/show_bug.cgi?id=4359> */
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| 26 | #if !(HAVE___FREADING && (!defined __GLIBC__ || defined __UCLIBC__ || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7)))
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| 27 |
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| 28 | bool
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| 29 | freading (FILE *fp)
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| 30 | {
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| 31 | /* Most systems provide FILE as a struct and the necessary bitmask in
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| 32 | <stdio.h>, because they need it for implementing getc() and putc() as
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| 33 | fast macros. */
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| 34 | # if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
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| 35 | /* GNU libc, BeOS, Haiku, Linux libc5 */
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| 36 | return ((fp->_flags & _IO_NO_WRITES) != 0
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| 37 | || ((fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
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| 38 | && fp->_IO_read_base != NULL));
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| 39 | # elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
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| 40 | /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */
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| 41 | return (fp_->_flags & __SRD) != 0;
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| 42 | # elif defined __EMX__ /* emx+gcc */
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| 43 | return (fp->_flags & _IOREAD) != 0;
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| 44 | # elif defined __minix /* Minix */
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| 45 | return (fp->_flags & _IOREADING) != 0;
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| 46 | # elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
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| 47 | # if defined __sun /* Solaris */
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| 48 | return (fp_->_flag & _IOREAD) != 0 && (fp_->_flag & _IOWRT) == 0;
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| 49 | # else
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| 50 | return (fp_->_flag & _IOREAD) != 0;
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| 51 | # endif
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| 52 | # elif defined __UCLIBC__ /* uClibc */
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| 53 | return (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) != 0;
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| 54 | # elif defined __QNX__ /* QNX */
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| 55 | return ((fp->_Mode & 0x2 /* _MOPENW */) == 0
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| 56 | || (fp->_Mode & 0x1000 /* _MREAD */) != 0);
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| 57 | # elif defined __MINT__ /* Atari FreeMiNT */
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| 58 | if (!fp->__mode.__write)
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| 59 | return 1;
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| 60 | if (!fp->__mode.__read)
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| 61 | return 0;
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| 62 | # ifdef _IO_CURRENTLY_GETTING /* Flag added on 2009-02-28 */
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| 63 | return (fp->__flags & _IO_CURRENTLY_GETTING) != 0;
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| 64 | # else
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| 65 | return (fp->__buffer < fp->__get_limit /*|| fp->__bufp == fp->__put_limit ??*/);
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| 66 | # endif
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| 67 | # elif defined EPLAN9 /* Plan9 */
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| 68 | if (fp->state == 0 /* CLOSED */ || fp->state == 4 /* WR */)
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| 69 | return 0;
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| 70 | return (fp->state == 3 /* RD */ && (fp->bufl == 0 || fp->rp < fp->wp));
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| 71 | # else
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| 72 | # error "Please port gnulib freading.c to your platform!"
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| 73 | # endif
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| 74 | }
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| 75 |
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| 76 | #endif
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