1/* Implement the vsnprintf function.
2   Copyright (C) 2003 Free Software Foundation, Inc.
3   Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.
4
5This file is part of the libiberty library.  This library is free
6software; you can redistribute it and/or modify it under the
7terms of the GNU General Public License as published by the
8Free Software Foundation; either version 2, or (at your option)
9any later version.
10
11This library is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with GNU CC; see the file COPYING.  If not, write to
18the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19
20As a special exception, if you link this library with files
21compiled with a GNU compiler to produce an executable, this does not cause
22the resulting executable to be covered by the GNU General Public License.
23This exception does not however invalidate any other reasons why
24the executable file might be covered by the GNU General Public License. */
25
26/*
27
28@deftypefn Supplemental int vsnprintf (char *@var{buf}, size_t @var{n}, const char *@var{format}, va_list @var{ap})
29
30This function is similar to vsprintf, but it will print at most
31@var{n} characters.  On error the return value is -1, otherwise it
32returns the number of characters that would have been printed had
33@var{n} been sufficiently large, regardless of the actual value of
34@var{n}.  Note some pre-C99 system libraries do not implement this
35correctly so users cannot generally rely on the return value if the
36system version of this function is used.
37
38@end deftypefn
39
40*/
41
42#include "config.h"
43#include "ansidecl.h"
44
45#ifdef ANSI_PROTOTYPES
46#include <stdarg.h>
47#else
48#include <varargs.h>
49#endif
50#ifdef HAVE_STRING_H
51#include <string.h>
52#endif
53#ifdef HAVE_STDLIB_H
54#include <stdlib.h>
55#endif
56
57#include "libiberty.h"
58
59/* This implementation relies on a working vasprintf.  */
60int
61vsnprintf (s, n, format, ap)
62     char * s;
63     size_t n;
64     const char *format;
65     va_list ap;
66{
67  char *buf = 0;
68  int result = vasprintf (&buf, format, ap);
69
70  if (!buf)
71    return -1;
72  if (result < 0)
73    {
74      free (buf);
75      return -1;
76    }
77
78  result = strlen (buf);
79  if (n > 0)
80    {
81      if ((long) n > result)
82	memcpy (s, buf, result+1);
83      else
84        {
85	  memcpy (s, buf, n-1);
86	  s[n - 1] = 0;
87	}
88    }
89  free (buf);
90  return result;
91}
92
93#ifdef TEST
94/* Set the buffer to a known state.  */
95#define CLEAR(BUF) do { memset ((BUF), 'X', sizeof (BUF)); (BUF)[14] = '\0'; } while (0)
96/* For assertions.  */
97#define VERIFY(P) do { if (!(P)) abort(); } while (0)
98
99static int ATTRIBUTE_PRINTF_3
100checkit VPARAMS ((char *s, size_t n, const char *format, ...))
101{
102  int result;
103  VA_OPEN (ap, format);
104  VA_FIXEDARG (ap, char *, s);
105  VA_FIXEDARG (ap, size_t, n);
106  VA_FIXEDARG (ap, const char *, format);
107  result = vsnprintf (s, n, format, ap);
108  VA_CLOSE (ap);
109  return result;
110}
111
112extern int main PARAMS ((void));
113int
114main ()
115{
116  char buf[128];
117  int status;
118
119  CLEAR (buf);
120  status = checkit (buf, 10, "%s:%d", "foobar", 9);
121  VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0);
122
123  CLEAR (buf);
124  status = checkit (buf, 9, "%s:%d", "foobar", 9);
125  VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0);
126
127  CLEAR (buf);
128  status = checkit (buf, 8, "%s:%d", "foobar", 9);
129  VERIFY (status==8 && memcmp (buf, "foobar:\0XXXXXX\0", 15) == 0);
130
131  CLEAR (buf);
132  status = checkit (buf, 7, "%s:%d", "foobar", 9);
133  VERIFY (status==8 && memcmp (buf, "foobar\0XXXXXXX\0", 15) == 0);
134
135  CLEAR (buf);
136  status = checkit (buf, 6, "%s:%d", "foobar", 9);
137  VERIFY (status==8 && memcmp (buf, "fooba\0XXXXXXXX\0", 15) == 0);
138
139  CLEAR (buf);
140  status = checkit (buf, 2, "%s:%d", "foobar", 9);
141  VERIFY (status==8 && memcmp (buf, "f\0XXXXXXXXXXXX\0", 15) == 0);
142
143  CLEAR (buf);
144  status = checkit (buf, 1, "%s:%d", "foobar", 9);
145  VERIFY (status==8 && memcmp (buf, "\0XXXXXXXXXXXXX\0", 15) == 0);
146
147  CLEAR (buf);
148  status = checkit (buf, 0, "%s:%d", "foobar", 9);
149  VERIFY (status==8 && memcmp (buf, "XXXXXXXXXXXXXX\0", 15) == 0);
150
151  return 0;
152}
153#endif /* TEST */
154