41 lines
870 B
C
41 lines
870 B
C
/*
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* fseek.c - perform an fseek
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*/
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/* $Id$ */
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include "loc_incl.h"
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int fseek(FILE* stream, long int offset, int whence)
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{
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int adjust = 0;
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long pos;
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stream->_flags &= ~(_IOEOF | _IOERR);
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/* Clear both the end of file and error flags */
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if (io_testflag(stream, _IOREADING))
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{
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if (whence == SEEK_CUR
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&& stream->_buf
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&& !io_testflag(stream, _IONBF))
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adjust = stream->_count;
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stream->_count = 0;
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}
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else if (io_testflag(stream, _IOWRITING))
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{
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fflush(stream);
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}
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else /* neither reading nor writing. The buffer must be empty */
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/* EMPTY */;
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pos = lseek(fileno(stream), offset - adjust, whence);
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if (io_testflag(stream, _IOREAD) && io_testflag(stream, _IOWRITE))
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stream->_flags &= ~(_IOREADING | _IOWRITING);
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stream->_ptr = stream->_buf;
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return ((pos == -1) ? -1 : 0);
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}
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