56 lines
1.8 KiB
C
56 lines
1.8 KiB
C
/*
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* Copyright (c) 2012, 2013, 2014 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* stdio/fflush_stop_reading_unlocked.c
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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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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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