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 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)vsnprintf.c 8.1 (Berkeley) 6/4/93 37 * $FreeBSD: src/lib/libc/stdio/vsnprintf.c,v 1.12.2.1 2002/09/23 06:58:17 maxim Exp $ 38 * $DragonFly: src/lib/libc/stdio/vsnprintf.c,v 1.5 2005/05/09 12:43:40 davidxu Exp $ 39 */ 40 41 #include <limits.h> 42 #include <stdio.h> 43 #include <stdarg.h> 44 #include "local.h" 45 46 int 47 vsnprintf(char *str, size_t n, const char *fmt, va_list ap) 48 { 49 size_t on; 50 int ret; 51 char dummy; 52 FILE f; 53 struct __sFILEX ext; 54 55 on = n; 56 if (n != 0) 57 n--; 58 if (n > INT_MAX) 59 n = INT_MAX; 60 /* Stdio internals do not deal correctly with zero length buffer */ 61 if (n == 0) { 62 str = &dummy; 63 n = 1; 64 } 65 f._file = -1; 66 f._flags = __SWR | __SSTR; 67 f._bf._base = f._p = (unsigned char *)str; 68 f._bf._size = f._w = n; 69 f._extra = &ext; 70 INITEXTRA(&f); 71 ret = __vfprintf(&f, fmt, ap); 72 if (on > 0) 73 *f._p = '\0'; 74 return (ret); 75 } 76