1/* Implement the vsnprintf function.
2   Copyright (C) 2003, 2004, 2005, 2011, 2013 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}, @
29  const char *@var{format}, va_list @var{ap})
30
31This function is similar to @code{vsprintf}, but it will write to
32@var{buf} at most @code{@var{n}-1} bytes of text, followed by a
33terminating null byte, for a total of @var{n} bytes.  On error the
34return value is -1, otherwise it returns the number of characters that
35would have been printed had @var{n} been sufficiently large,
36regardless of the actual value of @var{n}.  Note some pre-C99 system
37libraries do not implement this correctly so users cannot generally
38rely on the return value if the system version of this function is
39used.
40
41@end deftypefn
42
43*/
44
45#include "config.h"
46#include "ansidecl.h"
47
48#include <stdarg.h>
49#ifdef HAVE_STRING_H
50#include <string.h>
51#endif
52#ifdef HAVE_STDLIB_H
53#include <stdlib.h>
54#endif
55
56#include "libiberty.h"
57
58/* This implementation relies on a working vasprintf.  */
59int
60vsnprintf (char *s, size_t n, const char *format, va_list ap)
61{
62  char *buf = 0;
63  int result = vasprintf (&buf, format, ap);
64
65  if (!buf)
66    return -1;
67  if (result < 0)
68    {
69      free (buf);
70      return -1;
71    }
72
73  result = strlen (buf);
74  if (n > 0)
75    {
76      if ((long) n > result)
77	memcpy (s, buf, result+1);
78      else
79        {
80	  memcpy (s, buf, n-1);
81	  s[n - 1] = 0;
82	}
83    }
84  free (buf);
85  return result;
86}
87
88#ifdef TEST
89/* Set the buffer to a known state.  */
90#define CLEAR(BUF) do { memset ((BUF), 'X', sizeof (BUF)); (BUF)[14] = '\0'; } while (0)
91/* For assertions.  */
92#define VERIFY(P) do { if (!(P)) abort(); } while (0)
93
94static int ATTRIBUTE_PRINTF_3
95checkit (char *s, size_t n, const char *format, ...)
96{
97  int result;
98  va_list ap;
99  va_start (ap, format);
100  result = vsnprintf (s, n, format, ap);
101  va_end (ap);
102  return result;
103}
104
105extern int main (void);
106int
107main (void)
108{
109  char buf[128];
110  int status;
111
112  CLEAR (buf);
113  status = checkit (buf, 10, "%s:%d", "foobar", 9);
114  VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0);
115
116  CLEAR (buf);
117  status = checkit (buf, 9, "%s:%d", "foobar", 9);
118  VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0);
119
120  CLEAR (buf);
121  status = checkit (buf, 8, "%s:%d", "foobar", 9);
122  VERIFY (status==8 && memcmp (buf, "foobar:\0XXXXXX\0", 15) == 0);
123
124  CLEAR (buf);
125  status = checkit (buf, 7, "%s:%d", "foobar", 9);
126  VERIFY (status==8 && memcmp (buf, "foobar\0XXXXXXX\0", 15) == 0);
127
128  CLEAR (buf);
129  status = checkit (buf, 6, "%s:%d", "foobar", 9);
130  VERIFY (status==8 && memcmp (buf, "fooba\0XXXXXXXX\0", 15) == 0);
131
132  CLEAR (buf);
133  status = checkit (buf, 2, "%s:%d", "foobar", 9);
134  VERIFY (status==8 && memcmp (buf, "f\0XXXXXXXXXXXX\0", 15) == 0);
135
136  CLEAR (buf);
137  status = checkit (buf, 1, "%s:%d", "foobar", 9);
138  VERIFY (status==8 && memcmp (buf, "\0XXXXXXXXXXXXX\0", 15) == 0);
139
140  CLEAR (buf);
141  status = checkit (buf, 0, "%s:%d", "foobar", 9);
142  VERIFY (status==8 && memcmp (buf, "XXXXXXXXXXXXXX\0", 15) == 0);
143
144  return 0;
145}
146#endif /* TEST */
147