First step to cleaning up stdio. This breaks the libc ABI, all programs
[dragonfly.git] / lib / libc / stdio / vsnprintf.c
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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.
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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 $
55b5af84 38 * $DragonFly: src/lib/libc/stdio/vsnprintf.c,v 1.6 2005/07/23 20:23:06 joerg Exp $
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39 */
40
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41#include <limits.h>
42#include <stdio.h>
41e8adcb 43#include <stdarg.h>
55b5af84 44
17ea2221 45#include "local.h"
55b5af84 46#include "priv_stdio.h"
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47
48int
41e8adcb 49vsnprintf(char *str, size_t n, const char *fmt, va_list ap)
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50{
51 size_t on;
52 int ret;
53 char dummy;
54 FILE f;
19c7a913 55 struct __sFILEX ext;
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56
57 on = n;
58 if (n != 0)
59 n--;
60 if (n > INT_MAX)
61 n = INT_MAX;
62 /* Stdio internals do not deal correctly with zero length buffer */
63 if (n == 0) {
64 str = &dummy;
65 n = 1;
66 }
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67 f.pub._fileno = -1;
68 f.pub._flags = __SWR | __SSTR;
69 f._bf._base = f.pub._p = (unsigned char *)str;
70 f._bf._size = f.pub._w = n;
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71 f._extra = &ext;
72 INITEXTRA(&f);
17ea2221 73 ret = __vfprintf(&f, fmt, ap);
984263bc 74 if (on > 0)
55b5af84 75 *f.pub._p = '\0';
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76 return (ret);
77}