What is the fastest way to Parse a line in Delphi?

I have a huge file that I must parse line by line. Speed is of the essence.

Example of a line:

Token-1   Here-is-the-Next-Token      Last-Token-on-Line
      ^                        ^
   Current                 Position
   Position              after GetToken

GetToken is called, returning "Here-is-the-Next-Token" and sets the CurrentPosition to the position of the last character of the token so that it is ready for the next call to GetToken. Tokens are separated by one or more spaces.

Assume the file is already in a StringList in memory. It fits in memory easily, say 200 MB.

I am worried only about the execution time for the parsing. What code will produce the absolute fastest execution in Delphi (Pascal)?