1 /* Implement the vsnprintf function. 2 Copyright (C) 2003, 2004, 2005, 2011, 2013 Free Software Foundation, Inc. 3 Written by Kaveh R. Ghazi <ghazi (at) 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_list ap; 99 va_start (ap, format); 100 result = vsnprintf (s, n, format, ap); 101 va_end (ap); 102 return result; 103 } 104 105 extern int main (void); 106 int 107 main (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
