gonzui

    1: /*      $OpenBSD: vsnprintf.c,v 1.15 2009/11/09 00:18:28 kurt Exp $ */
    2: /*-
    3:  * Copyright (c) 1990, 1993
    4:  *      The Regents of the University of California.  All rights reserved.
    5:  *
    6:  * This code is derived from software contributed to Berkeley by
    7:  * Chris Torek.
    8:  *
    9:  * Redistribution and use in source and binary forms, with or without
   10:  * modification, are permitted provided that the following conditions
   11:  * are met:
   12:  * 1. Redistributions of source code must retain the above copyright
   13:  *    notice, this list of conditions and the following disclaimer.
   14:  * 2. Redistributions in binary form must reproduce the above copyright
   15:  *    notice, this list of conditions and the following disclaimer in the
   16:  *    documentation and/or other materials provided with the distribution.
   17:  * 3. Neither the name of the University nor the names of its contributors
   18:  *    may be used to endorse or promote products derived from this software
   19:  *    without specific prior written permission.
   20:  *
   21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31:  * SUCH DAMAGE.
   32:  */
   33: 
   34: #include <limits.h>
   35: #include <stdio.h>
   36: #include <string.h>
   37: #include "local.h"
   38: 
   39: int
   40: vsnprintf(char *str, size_t n, const char *fmt, __va_list ap)
   41: {
   42:         int ret;
   43:         char dummy;
   44:         FILE f;
   45:         struct __sfileext fext;
   46: 
   47:         _FILEEXT_SETUP(&f, &fext);
   48: 
   49:         /* While snprintf(3) specifies size_t stdio uses an int internally */
   50:         if (n > INT_MAX)
   51:                 n = INT_MAX;
   52:         /* Stdio internals do not deal correctly with zero length buffer */
   53:         if (n == 0) {
   54:                 str = &dummy;
   55:                 n = 1;
   56:         }
   57:         f._file = -1;
   58:         f._flags = __SWR | __SSTR;
   59:         f._bf._base = f._p = (unsigned char *)str;
   60:         f._bf._size = f._w = n - 1;
   61:         ret = __vfprintf(&f, fmt, ap);
   62:         *f._p = '\0';
   63:         return (ret);
   64: }