126 lines
3.9 KiB
C
126 lines
3.9 KiB
C
/* Retrieve information about a FILE stream.
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Copyright (C) 2007-2022 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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/* Specification. */
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#include "freadptr.h"
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#include <stdlib.h>
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#include "stdio-impl.h"
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/* This file is not used on systems that have the __freadptr function,
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namely musl libc. */
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const char *
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freadptr (FILE *fp, size_t *sizep)
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{
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size_t size;
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/* Keep this code in sync with freadahead! */
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#if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
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/* GNU libc, BeOS, Haiku, Linux libc5 */
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if (fp->_IO_write_ptr > fp->_IO_write_base)
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return NULL;
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size = fp->_IO_read_end - fp->_IO_read_ptr;
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if (size == 0)
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return NULL;
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*sizep = size;
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return (const char *) fp->_IO_read_ptr;
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#elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
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/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
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if ((fp_->_flags & __SWR) != 0 || fp_->_r < 0)
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return NULL;
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size = fp_->_r;
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if (size == 0)
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return NULL;
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*sizep = size;
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return (const char *) fp_->_p;
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#elif defined __EMX__ /* emx+gcc */
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if ((fp->_flags & _IOWRT) != 0)
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return NULL;
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/* Note: fp->_ungetc_count > 0 implies fp->_rcount <= 0,
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fp->_ungetc_count = 0 implies fp->_rcount >= 0. */
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if (fp->_rcount <= 0)
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return NULL;
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if (!(fp->_ungetc_count == 0))
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abort ();
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*sizep = fp->_rcount;
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return fp->_ptr;
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#elif defined __minix /* Minix */
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if ((fp_->_flags & _IOWRITING) != 0)
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return NULL;
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size = fp_->_count;
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if (size == 0)
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return NULL;
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*sizep = size;
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return (const char *) fp_->_ptr;
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#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
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if ((fp_->_flag & _IOWRT) != 0)
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return NULL;
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size = fp_->_cnt;
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if (size == 0)
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return NULL;
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*sizep = size;
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return (const char *) fp_->_ptr;
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#elif defined __UCLIBC__ /* uClibc */
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# ifdef __STDIO_BUFFERS
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if (fp->__modeflags & __FLAG_WRITING)
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return NULL;
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if (fp->__modeflags & __FLAG_UNGOT)
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return NULL;
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size = fp->__bufread - fp->__bufpos;
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if (size == 0)
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return NULL;
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*sizep = size;
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return (const char *) fp->__bufpos;
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# else
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return NULL;
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# endif
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#elif defined __QNX__ /* QNX */
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if ((fp->_Mode & 0x2000 /* _MWRITE */) != 0)
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return NULL;
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/* fp->_Buf <= fp->_Next <= fp->_Rend */
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size = fp->_Rend - fp->_Next;
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if (size == 0)
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return NULL;
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*sizep = size;
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return (const char *) fp->_Next;
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#elif defined __MINT__ /* Atari FreeMiNT */
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if (!fp->__mode.__read)
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return NULL;
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size = fp->__get_limit - fp->__bufp;
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if (size == 0)
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return NULL;
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*sizep = size;
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return fp->__bufp;
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#elif defined EPLAN9 /* Plan9 */
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if (fp->state == 4 /* WR */)
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return NULL;
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if (fp->rp >= fp->wp)
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return NULL;
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*sizep = fp->wp - fp->rp;
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return fp->rp;
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#elif defined SLOW_BUT_NO_HACKS /* users can define this */
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/* This implementation is correct on any ANSI C platform. It is just
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awfully slow. */
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return NULL;
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#else
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#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."
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#endif
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}
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