| 1 | /* Formatted output to strings. |
| 2 | Copyright (C) 2004, 2006-2014 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 Lesser General Public License as published by |
| 7 | the Free Software Foundation; either version 2, 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 Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public License along |
| 16 | with this program; if not, see <http://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 | } |