diff options
Diffstat (limited to 'common/common.c')
| -rw-r--r-- | common/common.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/common/common.c b/common/common.c index e9cd70cf41..6084176610 100644 --- a/common/common.c +++ b/common/common.c @@ -16,6 +16,9 @@ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ +#include <stdarg.h> +#include <assert.h> + #include <libavutil/common.h> #include "talloc.h" @@ -104,6 +107,22 @@ bool mp_rect_intersection(struct mp_rect *rc, const struct mp_rect *rc2) return rc->x1 > rc->x0 && rc->y1 > rc->y0; } +// This works like snprintf(), except that it starts writing the first output +// character to str[strlen(str)]. This returns the number of characters the +// string would have assuming a large enough buffer, will make sure str is +// null-terminated, and will never write to str[size] or past. +int mp_snprintf_append(char *str, size_t size, const char *format, ...) +{ + size_t len = strnlen(str, size); + assert(!size || len < size); // str with no 0-termination is not allowed + int r; + va_list ap; + va_start(ap, format); + r = len + vsnprintf(str + len, size - len, format, ap); + va_end(ap); + return r; +} + // Encode the unicode codepoint as UTF-8, and append to the end of the // talloc'ed buffer. All guarantees bstr_xappend() give applies, such as // implicit \0-termination for convenience. |