1 /* Implement the vsnprintf function. 2 Copyright (C) 2003, 2004, 2005, 2011 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, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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}, @ 29 const char *@var{format}, va_list @var{ap}) 30 31 This 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 33 terminating null byte, for a total of @var{n} bytes. On error the 34 return value is -1, otherwise it returns the number of characters that 35 would have been printed had @var{n} been sufficiently large, 36 regardless of the actual value of @var{n}. Note some pre-C99 system 37 libraries do not implement this correctly so users cannot generally 38 rely on the return value if the system version of this function is 39 used. 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. */ 59 int 60 vsnprintf (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 94 static int ATTRIBUTE_PRINTF_3 95 checkit (char *s, size_t n, const char *format, ...) 96 { 97 int result; 98 VA_OPEN (ap, format); 99 VA_FIXEDARG (ap, char *, s); 100 VA_FIXEDARG (ap, size_t, n); 101 VA_FIXEDARG (ap, const char *, format); 102 result = vsnprintf (s, n, format, ap); 103 VA_CLOSE (ap); 104 return result; 105 } 106 107 extern int main (void); 108 int 109 main (void) 110 { 111 char buf[128]; 112 int status; 113 114 CLEAR (buf); 115 status = checkit (buf, 10, "%s:%d", "foobar", 9); 116 VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0); 117 118 CLEAR (buf); 119 status = checkit (buf, 9, "%s:%d", "foobar", 9); 120 VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0); 121 122 CLEAR (buf); 123 status = checkit (buf, 8, "%s:%d", "foobar", 9); 124 VERIFY (status==8 && memcmp (buf, "foobar:\0XXXXXX\0", 15) == 0); 125 126 CLEAR (buf); 127 status = checkit (buf, 7, "%s:%d", "foobar", 9); 128 VERIFY (status==8 && memcmp (buf, "foobar\0XXXXXXX\0", 15) == 0); 129 130 CLEAR (buf); 131 status = checkit (buf, 6, "%s:%d", "foobar", 9); 132 VERIFY (status==8 && memcmp (buf, "fooba\0XXXXXXXX\0", 15) == 0); 133 134 CLEAR (buf); 135 status = checkit (buf, 2, "%s:%d", "foobar", 9); 136 VERIFY (status==8 && memcmp (buf, "f\0XXXXXXXXXXXX\0", 15) == 0); 137 138 CLEAR (buf); 139 status = checkit (buf, 1, "%s:%d", "foobar", 9); 140 VERIFY (status==8 && memcmp (buf, "\0XXXXXXXXXXXXX\0", 15) == 0); 141 142 CLEAR (buf); 143 status = checkit (buf, 0, "%s:%d", "foobar", 9); 144 VERIFY (status==8 && memcmp (buf, "XXXXXXXXXXXXXX\0", 15) == 0); 145 146 return 0; 147 } 148 #endif /* TEST */ 149