164 lines
6 KiB
C
164 lines
6 KiB
C
/* An fseeko() function that, together with fflush(), is POSIX compliant.
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Copyright (C) 2007-2023 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 <stdio.h>
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/* Get off_t, lseek, _POSIX_VERSION. */
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#include <unistd.h>
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#include "stdio-impl.h"
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int
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fseeko (FILE *fp, off_t offset, int whence)
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#undef fseeko
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#if !HAVE_FSEEKO
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# undef fseek
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# define fseeko fseek
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#endif
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#if _GL_WINDOWS_64_BIT_OFF_T
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# undef fseeko
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# if HAVE__FSEEKI64 && HAVE_DECL__FSEEKI64 /* msvc, mingw since msvcrt8.0, mingw64 */
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# define fseeko _fseeki64
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# else /* mingw before msvcrt8.0 */
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# define fseeko fseeko64
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# endif
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#endif
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{
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#if LSEEK_PIPE_BROKEN
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/* mingw gives bogus answers rather than failure on non-seekable files. */
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if (lseek (fileno (fp), 0, SEEK_CUR) == -1)
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return EOF;
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#endif
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/* These tests are based on fpurge.c. */
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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_read_end == fp->_IO_read_ptr
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&& fp->_IO_write_ptr == fp->_IO_write_base
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&& fp->_IO_save_base == NULL)
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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 defined __SL64 && defined __SCLE /* Cygwin */
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if ((fp->_flags & __SL64) == 0)
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{
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/* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit
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mode; but has an fseeko that requires 64-bit mode. */
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FILE *tmp = fopen ("/dev/null", "r");
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if (!tmp)
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return -1;
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fp->_flags |= __SL64;
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fp->_seek64 = tmp->_seek64;
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fclose (tmp);
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}
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# endif
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if (fp_->_p == fp_->_bf._base
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&& fp_->_r == 0
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&& fp_->_w == ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
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? fp_->_bf._size
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: 0)
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&& fp_ub._base == NULL)
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#elif defined __EMX__ /* emx+gcc */
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if (fp->_ptr == fp->_buffer
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&& fp->_rcount == 0
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&& fp->_wcount == 0
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&& fp->_ungetc_count == 0)
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#elif defined __minix /* Minix */
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if (fp_->_ptr == fp_->_buf
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&& (fp_->_ptr == NULL || fp_->_count == 0))
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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_->_ptr == fp_->_base
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&& (fp_->_ptr == NULL || fp_->_cnt == 0))
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#elif defined __UCLIBC__ /* uClibc */
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if (((fp->__modeflags & __FLAG_WRITING) == 0
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|| fp->__bufpos == fp->__bufstart)
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&& ((fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) == 0
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|| fp->__bufpos == fp->__bufread))
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#elif defined __QNX__ /* QNX */
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if ((fp->_Mode & 0x2000 /* _MWRITE */ ? fp->_Next == fp->_Buf : fp->_Next == fp->_Rend)
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&& fp->_Rback == fp->_Back + sizeof (fp->_Back)
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&& fp->_Rsave == NULL)
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#elif defined __MINT__ /* Atari FreeMiNT */
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if (fp->__bufp == fp->__buffer
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&& fp->__get_limit == fp->__bufp
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&& fp->__put_limit == fp->__bufp
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&& !fp->__pushed_back)
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#elif defined EPLAN9 /* Plan9 */
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if (fp->rp == fp->buf
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&& fp->wp == fp->buf)
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#elif FUNC_FFLUSH_STDIN < 0 && 200809 <= _POSIX_VERSION
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/* Cross-compiling to some other system advertising conformance to
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POSIX.1-2008 or later. Assume fseeko and fflush work as advertised.
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If this assumption is incorrect, please report the bug to
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bug-gnulib. */
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if (0)
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#else
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#error "Please port gnulib fseeko.c to your platform! Look at the code in fseeko.c, then report this to bug-gnulib."
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#endif
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{
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/* We get here when an fflush() call immediately preceded this one (or
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if ftell() has created buffers but no I/O has occurred on a
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newly-opened stream). We know there are no buffers. */
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off_t pos = lseek (fileno (fp), offset, whence);
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if (pos == -1)
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{
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#if 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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fp_->_flags &= ~__SOFF;
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#endif
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return -1;
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}
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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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fp->_flags &= ~_IO_EOF_SEEN;
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fp->_offset = pos;
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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 defined __CYGWIN__ || (defined __NetBSD__ && __NetBSD_Version__ >= 600000000) || defined __minix
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/* fp_->_offset is typed as an integer. */
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fp_->_offset = pos;
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# else
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/* fp_->_offset is an fpos_t. */
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{
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/* Use a union, since on NetBSD, the compilation flags
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determine whether fpos_t is typedef'd to off_t or a struct
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containing a single off_t member. */
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union
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{
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fpos_t f;
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off_t o;
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} u;
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u.o = pos;
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fp_->_offset = u.f;
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}
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# endif
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fp_->_flags |= __SOFF;
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fp_->_flags &= ~__SEOF;
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#elif defined __EMX__ /* emx+gcc */
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fp->_flags &= ~_IOEOF;
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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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fp_->_flag &= ~_IOEOF;
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#elif defined __MINT__ /* Atari FreeMiNT */
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fp->__offset = pos;
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fp->__eof = 0;
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#endif
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return 0;
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}
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return fseeko (fp, offset, whence);
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}
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