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/* Retrieve information about 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 "freadptr.h"
#include <stdlib.h>
#include "stdio-impl.h"
/* This file is not used on systems that have the __freadptr function,
namely musl libc. */
const char *
freadptr (FILE *fp, size_t *sizep)
{
size_t size;
/* Keep this code in sync with freadahead! */
#if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
/* GNU libc, BeOS, Haiku, Linux libc5 */
if (fp->_IO_write_ptr > fp->_IO_write_base)
return NULL;
size = fp->_IO_read_end - fp->_IO_read_ptr;
if (size == 0)
return NULL;
*sizep = size;
return (const char *) fp->_IO_read_ptr;
#elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
if ((fp_->_flags & __SWR) != 0 || fp_->_r < 0)
return NULL;
size = fp_->_r;
if (size == 0)
return NULL;
*sizep = size;
return (const char *) fp_->_p;
#elif defined __EMX__ /* emx+gcc */
if ((fp->_flags & _IOWRT) != 0)
return NULL;
/* Note: fp->_ungetc_count > 0 implies fp->_rcount <= 0,
fp->_ungetc_count = 0 implies fp->_rcount >= 0. */
if (fp->_rcount <= 0)
return NULL;
if (!(fp->_ungetc_count == 0))
abort ();
*sizep = fp->_rcount;
return fp->_ptr;
#elif defined __minix /* Minix */
if ((fp_->_flags & _IOWRITING) != 0)
return NULL;
size = fp_->_count;
if (size == 0)
return NULL;
*sizep = size;
return (const char *) fp_->_ptr;
#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
if ((fp_->_flag & _IOWRT) != 0)
return NULL;
size = fp_->_cnt;
if (size == 0)
return NULL;
*sizep = size;
return (const char *) fp_->_ptr;
#elif defined __UCLIBC__ /* uClibc */
# ifdef __STDIO_BUFFERS
if (fp->__modeflags & __FLAG_WRITING)
return NULL;
if (fp->__modeflags & __FLAG_UNGOT)
return NULL;
size = fp->__bufread - fp->__bufpos;
if (size == 0)
return NULL;
*sizep = size;
return (const char *) fp->__bufpos;
# else
return NULL;
# endif
#elif defined __QNX__ /* QNX */
if ((fp->_Mode & 0x2000 /* _MWRITE */) != 0)
return NULL;
/* fp->_Buf <= fp->_Next <= fp->_Rend */
size = fp->_Rend - fp->_Next;
if (size == 0)
return NULL;
*sizep = size;
return (const char *) fp->_Next;
#elif defined __MINT__ /* Atari FreeMiNT */
if (!fp->__mode.__read)
return NULL;
size = fp->__get_limit - fp->__bufp;
if (size == 0)
return NULL;
*sizep = size;
return fp->__bufp;
#elif defined EPLAN9 /* Plan9 */
if (fp->state == 4 /* WR */)
return NULL;
if (fp->rp >= fp->wp)
return NULL;
*sizep = fp->wp - fp->rp;
return fp->rp;
#elif defined SLOW_BUT_NO_HACKS /* users can define this */
/* This implementation is correct on any ANSI C platform. It is just
awfully slow. */
return NULL;
#else
#error "Please port gnulib freadptr.c to your platform! Look at the definition of fflush, fread, getc, getc_unlocked on your system, then report this to bug-gnulib."
#endif
}
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