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      1 /*	$NetBSD: fgetwln.c,v 1.8 2016/08/27 13:15:48 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2002-2004 Tim J. Robbins.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 #if defined(LIBC_SCCS) && !defined(lint)
     31 #if 0
     32 __FBSDID("$FreeBSD: src/lib/libc/stdio/fgetwln.c,v 1.2 2004/08/06 17:00:09 tjr Exp $");
     33 #else
     34 __RCSID("$NetBSD: fgetwln.c,v 1.8 2016/08/27 13:15:48 christos Exp $");
     35 #endif
     36 #endif /* LIBC_SCCS and not lint */
     37 
     38 #include "namespace.h"
     39 #include <assert.h>
     40 #include <errno.h>
     41 #include <limits.h>
     42 #include <stdio.h>
     43 #include <stdlib.h>
     44 #include <wchar.h>
     45 #include "reentrant.h"
     46 #include "local.h"
     47 
     48 #ifdef __weak_alias
     49 __weak_alias(fgetwln,_fgetwln)
     50 #endif
     51 
     52 /*
     53  * Expand the line buffer.  Return -1 on error.
     54 #ifdef notdef
     55  * The `new size' does not account for a terminating '\0',
     56  * so we add 1 here.
     57 #endif
     58  */
     59 static int
     60 __slbexpand(FILE *fp, size_t newsize)
     61 {
     62 	void *p;
     63 
     64 #ifdef notdef
     65 	++newsize;
     66 #endif
     67 	_DIAGASSERT(fp != NULL);
     68 
     69 	if (_EXT(fp)->_fgetstr_len >= newsize)
     70 		return 0;
     71 	if ((p = realloc(_EXT(fp)->_fgetstr_buf, newsize)) == NULL)
     72 		return -1;
     73 	_EXT(fp)->_fgetstr_buf = p;
     74 	_EXT(fp)->_fgetstr_len = newsize;
     75 	return 0;
     76 }
     77 
     78 wchar_t *
     79 fgetwln(FILE * __restrict fp, size_t *lenp)
     80 {
     81 	wint_t wc;
     82 	size_t len;
     83 
     84 	FLOCKFILE(fp);
     85 	_SET_ORIENTATION(fp, 1);
     86 
     87 	len = 0;
     88 	while ((wc = __fgetwc_unlock(fp)) != WEOF) {
     89 #define	GROW	512
     90 		if (len * sizeof(wchar_t) >= _EXT(fp)->_fgetstr_len &&
     91 		    __slbexpand(fp, (len + GROW) * sizeof(wchar_t))) {
     92 			fp->_flags |= __SERR;
     93 			goto error;
     94 		}
     95 		*((wchar_t *)(void *)_EXT(fp)->_fgetstr_buf + len++) = wc;
     96 		if (wc == L'\n')
     97 			break;
     98 	}
     99 
    100 	/*
    101 	 * The following test assumes that fgetwc() fails when
    102 	 * feof() is already set, and that fgetwc() will never
    103 	 * set feof() in the same call where it also sets ferror()
    104 	 * or returns non-WEOF.
    105 	 * Testing ferror() would not be better because fgetwc()
    106 	 * may succeed even when ferror() is already set.
    107 	 */
    108 
    109 	if (len == 0 || (wc == WEOF && !__sfeof(fp)))
    110 		goto error;
    111 
    112 	FUNLOCKFILE(fp);
    113 	*lenp = len;
    114 	return (wchar_t *)(void *)_EXT(fp)->_fgetstr_buf;
    115 
    116 error:
    117 	FUNLOCKFILE(fp);
    118 	*lenp = 0;
    119 	return NULL;
    120 }
    121