The mapping file consists of a series of separate tables. Each table begins with its name.
Names always have an alphabetic character in the first column.
The table name is followed by a required blank line, and then by the entries in the table. Entries consist of zero or more indented lines. Each entry line consists of two columns separated by one or more spaces or tabs. Any spaces within an entry must be quoted. Each pattern or template can contain up to 252 characters.