Added __vrsnprintf

1 files changed, 16 insertions, 0 deletions

diff --git a/include/jacson.h b/include/jacson.h
index aca103b..2dc7369 100644
--- a/include/jacson.h
+++ b/include/jacson.h
@@ -145,6 +145,7 @@ bool jacson_try_get_to(jacson_value *obj, enum jacson_type type, void *mem);
 
 #ifdef JACSON_EXPORT_RSNPRINTF
 size_t __jacson_rsnprintf(char **str, size_t *strsz, size_t off, const char *fmt, ...);
+size_t __jacson_vrsnprintf(char **str, size_t *strsz, size_t off, const char *fmt, va_list ls);
 size_t __jacson_rsnputc(char **str, size_t *strsz, size_t off, char c);
 #endif // JACSON_EXPORT_RSNPRINTF
 
@@ -225,6 +226,21 @@ try_write:
 	va_end(ls);
 	return ln;
 }
+size_t __jacson_vrsnprintf(char **const str, size_t *strsz, size_t off, const char *fmt, va_list ls) {
+	va_list ls1;
+	size_t ln;
+try_write:
+	va_copy(ls1, ls);
+		ln = vsnprintf(*str + off, *strsz-off, fmt, ls1);
+	va_end(ls1);
+	if (ln >= *strsz-off) {
+		*strsz <<= 1;
+		*str = realloc(*str, *strsz);
+		goto try_write;
+	}
+	va_end(ls);
+	return ln;
+}
 size_t __jacson_rsnputc(char **const str, size_t *strsz, size_t off, char c) {
 	if (*strsz - off <= 1) {
 		*strsz <<= 1;