61 lines
1.9 KiB
C++
61 lines
1.9 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012, 2013, 2014.
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This file is part of the Sortix C Library.
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The Sortix C Library 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 published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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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 the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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stdio/fflush_stop_reading_unlocked.cpp
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Resets the FILE to a consistent state ready for writing.
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*******************************************************************************/
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#include <stdint.h>
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#include <stdio.h>
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extern "C" int fflush_stop_reading_unlocked(FILE* fp)
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{
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if ( !(fp->flags & _FILE_LAST_READ) )
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return 0;
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if ( !(fp->flags & _FILE_READABLE) )
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return errno = EBADF, fp->flags |= _FILE_STATUS_ERROR, EOF;
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int saved_errno = errno;
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off_t my_pos = -1;
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if ( fp->seek_func )
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my_pos = fp->seek_func(fp->user, 0, SEEK_CUR);
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errno = saved_errno;
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int ret = 0;
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if ( 0 <= my_pos )
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{
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size_t buffer_ahead = fp->amount_input_buffered - fp->offset_input_buffer;
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off_t expected_pos = (uintmax_t) my_pos < (uintmax_t) buffer_ahead ? 0 :
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my_pos - buffer_ahead;
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if ( 0 <= my_pos && fp->seek_func(fp->user, expected_pos, SEEK_SET) < 0 )
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fp->flags |= _FILE_STATUS_ERROR, ret = EOF;
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}
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fp->amount_input_buffered = fp->offset_input_buffer = 0;
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fp->flags &= ~_FILE_LAST_READ;
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return ret;
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}
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