1 | /* Formatted output to strings. |
2 | Copyright (C) 2004, 2006-2019 Free Software Foundation, Inc. |
3 | Written by Simon Josefsson and Paul Eggert. |
4 | |
5 | This program is free software; you can redistribute it and/or modify |
6 | it under the terms of the GNU General Public License as published by |
7 | the Free Software Foundation; either version 3, or (at your option) |
8 | any later version. |
9 | |
10 | This program is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 | GNU General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU General Public License along |
16 | with this program; if not, see <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include <config.h> |
19 | |
20 | /* Specification. */ |
21 | #include <stdio.h> |
22 | |
23 | #include <errno.h> |
24 | #include <limits.h> |
25 | #include <stdarg.h> |
26 | #include <stdlib.h> |
27 | #include <string.h> |
28 | |
29 | #include "vasnprintf.h" |
30 | |
31 | /* Print formatted output to string STR. Similar to sprintf, but |
32 | additional length SIZE limit how much is written into STR. Returns |
33 | string length of formatted string (which may be larger than SIZE). |
34 | STR may be NULL, in which case nothing will be written. On error, |
35 | return a negative value. */ |
36 | int |
37 | snprintf (char *str, size_t size, const char *format, ...) |
38 | { |
39 | char *output; |
40 | size_t len; |
41 | size_t lenbuf = size; |
42 | va_list args; |
43 | |
44 | va_start (args, format); |
45 | output = vasnprintf (str, &lenbuf, format, args); |
46 | len = lenbuf; |
47 | va_end (args); |
48 | |
49 | if (!output) |
50 | return -1; |
51 | |
52 | if (output != str) |
53 | { |
54 | if (size) |
55 | { |
56 | size_t pruned_len = (len < size ? len : size - 1); |
57 | memcpy (str, output, pruned_len); |
58 | str[pruned_len] = '\0'; |
59 | } |
60 | |
61 | free (output); |
62 | } |
63 | |
64 | if (INT_MAX < len) |
65 | { |
66 | errno = EOVERFLOW; |
67 | return -1; |
68 | } |
69 | |
70 | return len; |
71 | } |
72 | |