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    /*	$OpenBSD: setvbuf.c,v 1.14 2016/09/21 04:38:56 guenther Exp $ */  | 
    
    
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    /*-  | 
    
    
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     * Copyright (c) 1990, 1993  | 
    
    
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     *	The Regents of the University of California.  All rights reserved.  | 
    
    
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     *  | 
    
    
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     * This code is derived from software contributed to Berkeley by  | 
    
    
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     * Chris Torek.  | 
    
    
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     *  | 
    
    
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     * Redistribution and use in source and binary forms, with or without  | 
    
    
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     * modification, are permitted provided that the following conditions  | 
    
    
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     * are met:  | 
    
    
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     * 1. Redistributions of source code must retain the above copyright  | 
    
    
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     *    notice, this list of conditions and the following disclaimer.  | 
    
    
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     * 2. Redistributions in binary form must reproduce the above copyright  | 
    
    
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     *    notice, this list of conditions and the following disclaimer in the  | 
    
    
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     *    documentation and/or other materials provided with the distribution.  | 
    
    
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     * 3. Neither the name of the University nor the names of its contributors  | 
    
    
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     *    may be used to endorse or promote products derived from this software  | 
    
    
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     *    without specific prior written permission.  | 
    
    
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     *  | 
    
    
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     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND  | 
    
    
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     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE  | 
    
    
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     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE  | 
    
    
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     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE  | 
    
    
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     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL  | 
    
    
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     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS  | 
    
    
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     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)  | 
    
    
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     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT  | 
    
    
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     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY  | 
    
    
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     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF  | 
    
    
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     * SUCH DAMAGE.  | 
    
    
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     */  | 
    
    
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    #include <stdio.h>  | 
    
    
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    #include <stdlib.h>  | 
    
    
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    #include "local.h"  | 
    
    
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    /*  | 
    
    
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     * Set one of the three kinds of buffering, optionally including  | 
    
    
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     * a buffer.  | 
    
    
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     */  | 
    
    
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    int  | 
    
    
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    setvbuf(FILE *fp, char *buf, int mode, size_t size)  | 
    
    
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    { | 
    
    
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    	int ret, flags;  | 
    
    
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    	size_t iosize;  | 
    
    
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    	int ttyflag;  | 
    
    
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    	/*  | 
    
    
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    	 * Verify arguments.  The `int' limit on `size' is due to this  | 
    
    
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    	 * particular implementation.  Note, buf and size are ignored  | 
    
    
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    	 * when setting _IONBF.  | 
    
    
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    	 */  | 
    
    
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    	if (mode != _IONBF)  | 
    
    
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    		if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0)  | 
    
    
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    			return (EOF);  | 
    
    
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    	/*  | 
    
    
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    	 * Write current buffer, if any.  Discard unread input (including  | 
    
    
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    	 * ungetc data), cancel line buffering, and free old buffer if  | 
    
    
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    	 * malloc()ed.  We also clear any eof condition, as if this were  | 
    
    
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    	 * a seek.  | 
    
    
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    	 */  | 
    
    
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    	FLOCKFILE(fp);  | 
    
    
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    	ret = 0;  | 
    
    
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    	(void)__sflush(fp);  | 
    
    
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    	if (HASUB(fp))  | 
    
    
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    		FREEUB(fp);  | 
    
    
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    	WCIO_FREE(fp);  | 
    
    
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    	fp->_r = fp->_lbfsize = 0;  | 
    
    
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    	flags = fp->_flags;  | 
    
    
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    	if (flags & __SMBF)  | 
    
    
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    		free(fp->_bf._base);  | 
    
    
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    	flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF);  | 
    
    
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    	/* If setting unbuffered mode, skip all the hard work. */  | 
    
    
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    	if (mode == _IONBF)  | 
    
    
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    		goto nbf;  | 
    
    
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    	/*  | 
    
    
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    	 * Find optimal I/O size for seek optimization.  This also returns  | 
    
    
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    	 * a `tty flag' to suggest that we check isatty(fd), but we do not  | 
    
    
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    	 * care since our caller told us how to buffer.  | 
    
    
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    	 */  | 
    
    
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    	flags |= __swhatbuf(fp, &iosize, &ttyflag);  | 
    
    
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    	if (size == 0) { | 
    
    
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    		buf = NULL;	/* force local allocation */  | 
    
    
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    		size = iosize;  | 
    
    
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    	}  | 
    
    
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    	/* Allocate buffer if needed. */  | 
    
    
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    	if (buf == NULL) { | 
    
    
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    		if ((buf = malloc(size)) == NULL) { | 
    
    
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    			/*  | 
    
    
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    			 * Unable to honor user's request.  We will return  | 
    
    
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    			 * failure, but try again with file system size.  | 
    
    
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    			 */  | 
    
    
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    			ret = EOF;  | 
    
    
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    			if (size != iosize) { | 
    
    
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    				size = iosize;  | 
    
    
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    				buf = malloc(size);  | 
    
    
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    			}  | 
    
    
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    		}  | 
    
    
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    		if (buf == NULL) { | 
    
    
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    			/* No luck; switch to unbuffered I/O. */  | 
    
    
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    nbf:  | 
    
    
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    			fp->_flags = flags | __SNBF;  | 
    
    
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    			fp->_w = 0;  | 
    
    
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    			fp->_bf._base = fp->_p = fp->_nbuf;  | 
    
    
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    			fp->_bf._size = 1;  | 
    
    
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    			FUNLOCKFILE(fp);  | 
    
    
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    			return (ret);  | 
    
    
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    		}  | 
    
    
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    		flags |= __SMBF;  | 
    
    
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    	}  | 
    
    
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    	/*  | 
    
    
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    	 * We're committed to buffering from here, so make sure we've  | 
    
    
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    	 * registered to flush buffers on exit.  | 
    
    
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    	 */  | 
    
    
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    	if (!__sdidinit)  | 
    
    
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    		__sinit();  | 
    
    
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    	/*  | 
    
    
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    	 * Kill any seek optimization if the buffer is not the  | 
    
    
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    	 * right size.  | 
    
    
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    	 *  | 
    
    
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    	 * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)?  | 
    
    
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    	 */  | 
    
    
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    	if (size != iosize)  | 
    
    
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    		flags |= __SNPT;  | 
    
    
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    	/*  | 
    
    
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    	 * Fix up the FILE fields, and set __cleanup for output flush on  | 
    
    
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    	 * exit (since we are buffered in some way).  | 
    
    
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    	 */  | 
    
    
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    	if (mode == _IOLBF)  | 
    
    
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    		flags |= __SLBF;  | 
    
    
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    	fp->_flags = flags;  | 
    
    
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    	fp->_bf._base = fp->_p = (unsigned char *)buf;  | 
    
    
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    	fp->_bf._size = size;  | 
    
    
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    	/* fp->_lbfsize is still 0 */  | 
    
    
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    	if (flags & __SWR) { | 
    
    
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    		/*  | 
    
    
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    		 * Begin or continue writing: see __swsetup().  Note  | 
    
    
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    		 * that __SNBF is impossible (it was handled earlier).  | 
    
    
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    		 */  | 
    
    
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    		if (flags & __SLBF) { | 
    
    
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    			fp->_w = 0;  | 
    
    
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    			fp->_lbfsize = -fp->_bf._size;  | 
    
    
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    		} else  | 
    
    
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    			fp->_w = size;  | 
    
    
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    	} else { | 
    
    
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    		/* begin/continue reading, or stay in intermediate state */  | 
    
    
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    		fp->_w = 0;  | 
    
    
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    	}  | 
    
    
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    	FUNLOCKFILE(fp);  | 
    
    
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    	return (ret);  | 
    
    
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    }  | 
    
    
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    DEF_STRONG(setvbuf);  |