[PATCH] D39279: Stringizing raw string literals containing newline

[Jan Korous via Phabricator via cfe-commits]

jkorous-apple added a comment.

I am sorry I wasn't really clear. What I meant was to do something like this (pseudo-code, dealing only with newlines):

  if( Str.size() == 0)
    return;
  
  // Calculate all the extra space needed first.
  
  typename T::size_type extra_space = 0;
  bool previous_char_was_endline = false;
  
  for(const auto ch : Str) {
    if( ch == '\n' || ch == '\r' ) {
      if( !previous_char_was_endline )
        ++extra_space;
      previous_char_was_endline = true;
    } else {
      previous_char_was_endline = false;
    }
  }
  
  if (extra_space == 0)
    return; 
  
  // Resize the string.
  
  const typename T::size_type original_size = Str.size();
  Str.resize(original_size + extra_space);
  
  // Iterate backwards and move characters as needed.
  
  bool is_in_block_of_endlines = false;
  
  for(typename T::size_type i = original_size - 1; i > 0; --i) {
    if( Str[i] == '\n' || Str[i] == '\r' ) {
      if (!is_in_block_of_endlines) {
        Str[i + extra_space - 1] = '\\';
        Str[i + extra_space] = 'n';
        --extra_space;
        if(extra_space == 0)
          return; // early exit - no more characters need to be moved
      }
      is_in_block_of_endlines = true;
    } else {
      Str[i + extra_space] = Str[i];
      is_in_block_of_endlines = false;
    }
  }

This is just a suggestion, it is a bit more complicated but should be O(lenght_of_string) whereas your solution is a bit more straightforward but is more like O(length_of_string * number_of_endlines_in_string). I leave it up to you what is better here. If you decide to go this way, please assume my pseudocode is buggy and don't rely on it.


https://reviews.llvm.org/D39279