1 /*-

     2  * Copyright (c) 1990, 1993

     3  *	The Regents of the University of California.  All rights reserved.

     4  *

     5  * This code is derived from software contributed to Berkeley by

     6  * Chris Torek.

     7  *

     8  * Redistribution and use in source and binary forms, with or without

     9  * modification, are permitted provided that the following conditions

    10  * are met:

    11  * 1. Redistributions of source code must retain the above copyright

    12  *    notice, this list of conditions and the following disclaimer.

    13  * 2. Redistributions in binary form must reproduce the above copyright

    14  *    notice, this list of conditions and the following disclaimer in the

    15  *    documentation and/or other materials provided with the distribution.

    16  * 4. Neither the name of the University nor the names of its contributors

    17  *    may be used to endorse or promote products derived from this software

    18  *    without specific prior written permission.

    19  *

    20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

    21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

    23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

    24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

    25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

    26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

    27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

    28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

    29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

    30  * SUCH DAMAGE.

    31  */

    32 

    33 #if defined(LIBC_SCCS) && !defined(lint)

    34 static char sccsid[] = "@(#)wsetup.c	8.1 (Berkeley) 6/4/93";

    35 #endif /* LIBC_SCCS and not lint */

    36 #include <sys/cdefs.h>

    37 __FBSDID("$FreeBSD: src/lib/libc/stdio/wsetup.c,v 1.9 2004/06/08 05:44:52 das Exp $");

    38 

    39 #include <errno.h>

    40 #include <stdio.h>

    41 #include <stdlib.h>

    42 #include "local.h"

    43 #if (defined(__SYMBIAN32__) && (defined(__WINSCW__) || defined(__WINS__)))

    44 #include "libc_wsd_defs.h"

    45 #endif

    46 

    47 #ifdef EMULATOR

    48 int *GET_WSD_VAR_NAME(__sdidinit, g)();

    49 #define __sdidinit (*GET_WSD_VAR_NAME(__sdidinit, g)())

    50 #endif //EMULATOR

    51 

    52 /*

    53  * Various output routines call wsetup to be sure it is safe to write,

    54  * because either _flags does not include __SWR, or _buf is NULL.

    55  * _wsetup returns 0 if OK to write; otherwise, it returns EOF and sets errno.

    56  */

    57 int

    58 __swsetup(fp)

    59 	FILE *fp;

    60 {

    61 	/* make sure stdio is set up */

    62 	if (!__sdidinit)

    63 		__sinit();

    64 

    65 	/*

    66 	 * If we are not writing, we had better be reading and writing.

    67 	 */

    68 	if ((fp->_flags & __SWR) == 0) {

    69 		if ((fp->_flags & __SRW) == 0) {

    70 			errno = EBADF;

    71 #ifdef __SYMBIAN32__

    72 			fp->_flags |= __SERR;

    73 #endif			

    74 			return (EOF);

    75 		}

    76 		if (fp->_flags & __SRD) {

    77 			/* clobber any ungetc data */

    78 			if (HASUB(fp))

    79 				FREEUB(fp);

    80 			fp->_flags &= ~(__SRD|__SEOF);

    81 			

    82 			/*   Need to adjust the real-byte offset of the file

    83 			 *   depending on the value of fp->_r 

    84 			 *   before resetting its value.

    85 			 *   In binary-mode: seekBackCount = No. of unread bytes in buffer

    86 			 *   In text-mode: seekBackCount = (No. of unread chars in buffer + No. of newlines present as part of unread chars in buffer)

    87 			 */

    88 			if(fp->_r)

    89 			    {

    90 	            fpos_t offset = 0;

    91 	            

    92 	            /* Count newlines present as part of unread characters

    93 	             * in buffer denoted by ( fp->_r ) only in text-mode

    94 	             */ 

    95 	            if( fp->_extra->fmode == 't')

    96 	                {

    97 	                int newlines = 0, len = 0;

    98 	                char *p = NULL;

    99 	                p = (char*)(fp->_p);

   100 	                while( len++ < fp->_r )

   101 	                    {

   102 	                    if( *p++ == '\n' )

   103 	                        newlines++;

   104 	                    }

   105 	                offset += newlines;

   106 	                }

   107 	            

   108 	            offset += fp->_r;  

   109 			    if( (_sseek(fp, -(fpos_t)offset, SEEK_CUR)) == (-(fpos_t)1) )

   110 			        return (-1);

   111 			    }

   112 			fp->_r = 0;

   113 			fp->_p = fp->_bf._base;

   114 		}

   115 		fp->_flags |= __SWR;

   116 	}

   117 

   118 	/*

   119 	 * Make a buffer if necessary, then set _w.

   120 	 */

   121 	if (fp->_bf._base == NULL)

   122 	{

   123 		__smakebuf(fp);

   124 		if(fp->_bf._base == NULL && errno == ENOMEM)

   125 		{

   126 			return (EOF);

   127 		}

   128 	}

   129 	if (fp->_flags & __SLBF) {

   130 		/*

   131 		 * It is line buffered, so make _lbfsize be -_bufsize

   132 		 * for the putc() macro.  We will change _lbfsize back

   133 		 * to 0 whenever we turn off __SWR.

   134 		 */

   135 		fp->_w = 0;

   136 		fp->_lbfsize = -fp->_bf._size;

   137 	} else

   138 		fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;

   139 	return (0);

   140 }