+char *utf8_escape_invalid(const char *str) {
+ char *p, *s;
+
+ assert(str);
+
+ p = s = malloc(strlen(str) * 4 + 1);
+ if (!p)
+ return NULL;
+
+ while (*str) {
+ int len;
+
+ len = utf8_encoded_valid_unichar(str);
+ if (len > 0) {
+ s = mempcpy(s, str, len);
+ str += len;
+ } else {
+ s = mempcpy(s, UTF8_REPLACEMENT_CHARACTER, strlen(UTF8_REPLACEMENT_CHARACTER));
+ str += 1;
+ }
+ }
+
+ *s = '\0';
+
+ return p;
+}
+