diff options
Diffstat (limited to 'lib/fseeko.c')
| -rw-r--r-- | lib/fseeko.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/lib/fseeko.c b/lib/fseeko.c new file mode 100644 index 0000000..2dd4cdc --- /dev/null +++ b/lib/fseeko.c @@ -0,0 +1,146 @@ +/* An fseeko() function that, together with fflush(), is POSIX compliant. + Copyright (C) 2007-2011 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +#include <config.h> + +/* Specification. */ +#include <stdio.h> + +/* Get off_t and lseek. */ +#include <unistd.h> + +#include "stdio-impl.h" + +int +fseeko (FILE *fp, off_t offset, int whence) +#undef fseeko +#if !HAVE_FSEEKO +# undef fseek +# define fseeko fseek +#endif +{ +#if LSEEK_PIPE_BROKEN + /* mingw gives bogus answers rather than failure on non-seekable files. */ + if (lseek (fileno (fp), 0, SEEK_CUR) == -1) + return EOF; +#endif + + /* These tests are based on fpurge.c. */ +#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */ + if (fp->_IO_read_end == fp->_IO_read_ptr + && fp->_IO_write_ptr == fp->_IO_write_base + && fp->_IO_save_base == NULL) +#elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ +# if defined __SL64 && defined __SCLE /* Cygwin */ + if ((fp->_flags & __SL64) == 0) + { + /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit + mode; but has an fseeko that requires 64-bit mode. */ + FILE *tmp = fopen ("/dev/null", "r"); + if (!tmp) + return -1; + fp->_flags |= __SL64; + fp->_seek64 = tmp->_seek64; + fclose (tmp); + } +# endif + if (fp_->_p == fp_->_bf._base + && fp_->_r == 0 + && fp_->_w == ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */ + ? fp_->_bf._size + : 0) + && fp_ub._base == NULL) +#elif defined __EMX__ /* emx+gcc */ + if (fp->_ptr == fp->_buffer + && fp->_rcount == 0 + && fp->_wcount == 0 + && fp->_ungetc_count == 0) +#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw, NonStop Kernel */ + if (fp_->_ptr == fp_->_base + && (fp_->_ptr == NULL || fp_->_cnt == 0)) +#elif defined __UCLIBC__ /* uClibc */ + if (((fp->__modeflags & __FLAG_WRITING) == 0 + || fp->__bufpos == fp->__bufstart) + && ((fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) == 0 + || fp->__bufpos == fp->__bufread)) +#elif defined __QNX__ /* QNX */ + if ((fp->_Mode & 0x2000 /* _MWRITE */ ? fp->_Next == fp->_Buf : fp->_Next == fp->_Rend) + && fp->_Rback == fp->_Back + sizeof (fp->_Back) + && fp->_Rsave == NULL) +#elif defined __MINT__ /* Atari FreeMiNT */ + if (fp->__bufp == fp->__buffer + && fp->__get_limit == fp->__bufp + && fp->__put_limit == fp->__bufp + && !fp->__pushed_back) +#else + #error "Please port gnulib fseeko.c to your platform! Look at the code in fpurge.c, then report this to bug-gnulib." +#endif + { + /* We get here when an fflush() call immediately preceded this one. We + know there are no buffers. + POSIX requires us to modify the file descriptor's position. + But we cannot position beyond end of file here. */ + off_t pos = + lseek (fileno (fp), + whence == SEEK_END && offset > 0 ? 0 : offset, + whence); + if (pos == -1) + { +#if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ + fp_->_flags &= ~__SOFF; +#endif + return -1; + } + +#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */ + fp->_flags &= ~_IO_EOF_SEEN; +#elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ +# if defined __CYGWIN__ + /* fp_->_offset is typed as an integer. */ + fp_->_offset = pos; +# else + /* fp_->_offset is an fpos_t. */ + { + /* Use a union, since on NetBSD, the compilation flags + determine whether fpos_t is typedef'd to off_t or a struct + containing a single off_t member. */ + union + { + fpos_t f; + off_t o; + } u; + u.o = pos; + fp_->_offset = u.f; + } +# endif + fp_->_flags |= __SOFF; + fp_->_flags &= ~__SEOF; +#elif defined __EMX__ /* emx+gcc */ + fp->_flags &= ~_IOEOF; +#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw, NonStop Kernel */ + fp->_flag &= ~_IOEOF; +#elif defined __MINT__ /* Atari FreeMiNT */ + fp->__offset = pos; + fp->__eof = 0; +#endif + /* If we were not requested to position beyond end of file, we're + done. */ + if (!(whence == SEEK_END && offset > 0)) + return 0; + } + return fseeko (fp, offset, whence); +} |