1/* Implement the vsnprintf function.
2   Copyright (C) 2003, 2004, 2005 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, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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#include <stdarg.h>
46#ifdef HAVE_STRING_H
47#include <string.h>
48#endif
49#ifdef HAVE_STDLIB_H
50#include <stdlib.h>
51#endif
52
53#include "libiberty.h"
54
55/* This implementation relies on a working vasprintf.  */
56int
57vsnprintf (char *s, size_t n, const char *format, va_list ap)
58{
59  char *buf = 0;
60  int result = vasprintf (&buf, format, ap);
61
62  if (!buf)
63    return -1;
64  if (result < 0)
65    {
66      free (buf);
67      return -1;
68    }
69
70  result = strlen (buf);
71  if (n > 0)
72    {
73      if ((long) n > result)
74	memcpy (s, buf, result+1);
75      else
76        {
77	  memcpy (s, buf, n-1);
78	  s[n - 1] = 0;
79	}
80    }
81  free (buf);
82  return result;
83}
84
85#ifdef TEST
86/* Set the buffer to a known state.  */
87#define CLEAR(BUF) do { memset ((BUF), 'X', sizeof (BUF)); (BUF)[14] = '\0'; } while (0)
88/* For assertions.  */
89#define VERIFY(P) do { if (!(P)) abort(); } while (0)
90
91static int ATTRIBUTE_PRINTF_3
92checkit (char *s, size_t n, const char *format, ...)
93{
94  int result;
95  VA_OPEN (ap, format);
96  VA_FIXEDARG (ap, char *, s);
97  VA_FIXEDARG (ap, size_t, n);
98  VA_FIXEDARG (ap, const char *, format);
99  result = vsnprintf (s, n, format, ap);
100  VA_CLOSE (ap);
101  return result;
102}
103
104extern int main (void);
105int
106main (void)
107{
108  char buf[128];
109  int status;
110
111  CLEAR (buf);
112  status = checkit (buf, 10, "%s:%d", "foobar", 9);
113  VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0);
114
115  CLEAR (buf);
116  status = checkit (buf, 9, "%s:%d", "foobar", 9);
117  VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0);
118
119  CLEAR (buf);
120  status = checkit (buf, 8, "%s:%d", "foobar", 9);
121  VERIFY (status==8 && memcmp (buf, "foobar:\0XXXXXX\0", 15) == 0);
122
123  CLEAR (buf);
124  status = checkit (buf, 7, "%s:%d", "foobar", 9);
125  VERIFY (status==8 && memcmp (buf, "foobar\0XXXXXXX\0", 15) == 0);
126
127  CLEAR (buf);
128  status = checkit (buf, 6, "%s:%d", "foobar", 9);
129  VERIFY (status==8 && memcmp (buf, "fooba\0XXXXXXXX\0", 15) == 0);
130
131  CLEAR (buf);
132  status = checkit (buf, 2, "%s:%d", "foobar", 9);
133  VERIFY (status==8 && memcmp (buf, "f\0XXXXXXXXXXXX\0", 15) == 0);
134
135  CLEAR (buf);
136  status = checkit (buf, 1, "%s:%d", "foobar", 9);
137  VERIFY (status==8 && memcmp (buf, "\0XXXXXXXXXXXXX\0", 15) == 0);
138
139  CLEAR (buf);
140  status = checkit (buf, 0, "%s:%d", "foobar", 9);
141  VERIFY (status==8 && memcmp (buf, "XXXXXXXXXXXXXX\0", 15) == 0);
142
143  return 0;
144}
145#endif /* TEST */
146