make add_color_inplace safer

src/Text.hh

@@ -40,17 +40,18 @@ void replace_char_inplace(T* a, T f, T r) {
 }
 
 template <typename T>
-size_t add_color_inplace(T* a) {
+size_t add_color_inplace(T* a, size_t max_chars) {
   T* d = a;
   T* orig_d = d;
 
-  while (*a) {
+  for (size_t x = 0; (x < max_chars) && *a; x++) {
     if (*a == '$') {
       *(d++) = '\t';
     } else if (*a == '#') {
       *(d++) = '\n';
     } else if (*a == '%') {
       a++;
+      x++;
       if (*a == 's') {
         *(d++) = '$';
       } else if (*a == '%') {
@@ -69,9 +70,3 @@ size_t add_color_inplace(T* a) {
 
   return d - orig_d;
 }
-
-template <typename T>
-void add_color_inplace(std::basic_string<T>& a, size_t header_bytes) {
-  size_t count = add_color_inplace(a.data() + header_bytes);
-  a.resize(count + header_bytes);
-}