1 /* Implement the vsnprintf function.
2 Copyright (C) 2003 Free Software Foundation, Inc.
3 Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.
4
5 This file is part of the libiberty library. This library is free
6 software; you can redistribute it and/or modify it under the
7 terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19
20 As a special exception, if you link this library with files
21 compiled with a GNU compiler to produce an executable, this does not cause
22 the resulting executable to be covered by the GNU General Public License.
23 This exception does not however invalidate any other reasons why
24 the 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
30 This function is similar to vsprintf, but it will print at most
31 @var{n} characters. On error the return value is -1, otherwise it
32 returns 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
35 correctly so users cannot generally rely on the return value if the
36 system 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. */
60 int
vsnprintf(s,n,format,ap)61 vsnprintf (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
99 static int ATTRIBUTE_PRINTF_3
checkit(char * s,size_t n,const char * format,...)100 checkit 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
112 extern int main PARAMS ((void));
113 int
main()114 main ()
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