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 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}, const char *@var{format}, va_list @var{ap}) 29 30 This function is similar to @code{vsprintf}, but it will write to 31 @var{buf} at most @code{@var{n}-1} bytes of text, followed by a 32 terminating null byte, for a total of @var{n} bytes. On error the 33 return value is -1, otherwise it returns the number of characters that 34 would have been printed had @var{n} been sufficiently large, 35 regardless of the actual value of @var{n}. Note some pre-C99 system 36 libraries do not implement this correctly so users cannot generally 37 rely on the return value if the system version of this function is 38 used. 39 40 @end deftypefn 41 42 */ 43 44 #include "config.h" 45 #include "ansidecl.h" 46 47 #include <stdarg.h> 48 #ifdef HAVE_STRING_H 49 #include <string.h> 50 #endif 51 #ifdef HAVE_STDLIB_H 52 #include <stdlib.h> 53 #endif 54 55 #include "libiberty.h" 56 57 /* This implementation relies on a working vasprintf. */ 58 int 59 vsnprintf (char *s, size_t n, const char *format, va_list ap) 60 { 61 char *buf = 0; 62 int result = vasprintf (&buf, format, ap); 63 64 if (!buf) 65 return -1; 66 if (result < 0) 67 { 68 free (buf); 69 return -1; 70 } 71 72 result = strlen (buf); 73 if (n > 0) 74 { 75 if ((long) n > result) 76 memcpy (s, buf, result+1); 77 else 78 { 79 memcpy (s, buf, n-1); 80 s[n - 1] = 0; 81 } 82 } 83 free (buf); 84 return result; 85 } 86 87 #ifdef TEST 88 /* Set the buffer to a known state. */ 89 #define CLEAR(BUF) do { memset ((BUF), 'X', sizeof (BUF)); (BUF)[14] = '\0'; } while (0) 90 /* For assertions. */ 91 #define VERIFY(P) do { if (!(P)) abort(); } while (0) 92 93 static int ATTRIBUTE_PRINTF_3 94 checkit (char *s, size_t n, const char *format, ...) 95 { 96 int result; 97 VA_OPEN (ap, format); 98 VA_FIXEDARG (ap, char *, s); 99 VA_FIXEDARG (ap, size_t, n); 100 VA_FIXEDARG (ap, const char *, format); 101 result = vsnprintf (s, n, format, ap); 102 VA_CLOSE (ap); 103 return result; 104 } 105 106 extern int main (void); 107 int 108 main (void) 109 { 110 char buf[128]; 111 int status; 112 113 CLEAR (buf); 114 status = checkit (buf, 10, "%s:%d", "foobar", 9); 115 VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0); 116 117 CLEAR (buf); 118 status = checkit (buf, 9, "%s:%d", "foobar", 9); 119 VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0); 120 121 CLEAR (buf); 122 status = checkit (buf, 8, "%s:%d", "foobar", 9); 123 VERIFY (status==8 && memcmp (buf, "foobar:\0XXXXXX\0", 15) == 0); 124 125 CLEAR (buf); 126 status = checkit (buf, 7, "%s:%d", "foobar", 9); 127 VERIFY (status==8 && memcmp (buf, "foobar\0XXXXXXX\0", 15) == 0); 128 129 CLEAR (buf); 130 status = checkit (buf, 6, "%s:%d", "foobar", 9); 131 VERIFY (status==8 && memcmp (buf, "fooba\0XXXXXXXX\0", 15) == 0); 132 133 CLEAR (buf); 134 status = checkit (buf, 2, "%s:%d", "foobar", 9); 135 VERIFY (status==8 && memcmp (buf, "f\0XXXXXXXXXXXX\0", 15) == 0); 136 137 CLEAR (buf); 138 status = checkit (buf, 1, "%s:%d", "foobar", 9); 139 VERIFY (status==8 && memcmp (buf, "\0XXXXXXXXXXXXX\0", 15) == 0); 140 141 CLEAR (buf); 142 status = checkit (buf, 0, "%s:%d", "foobar", 9); 143 VERIFY (status==8 && memcmp (buf, "XXXXXXXXXXXXXX\0", 15) == 0); 144 145 return 0; 146 } 147 #endif /* TEST */ 148