suplib/src/RCSString.i3

 Copyright 1996-2003 John D. Polstra.
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 The RCSString interface provides an abstract interface to the text
   strings associated with RCS files.  Behind the abstract interface are
   hidden a number of different implementations, each appropriate for a
   different situation.  The goal of this approach is efficiency.


   For example, most strings that were present in the original RCS file
   are implemented as pointers into the memory-mapped image of the file
   itself.  Thus, those strings can contain huge numbers of characters
   without consuming any memory resources. 


INTERFACE RCSString;

CONST Brand = "RCSString";

TYPE
  T = OBJECT METHODS
    toText(): TEXT := NIL;
    numLines(): CARDINAL := NIL;
    iterate(): Iterator := NIL;
  END;

  Iterator = OBJECT METHODS
    next(VAR line: T): BOOLEAN := NIL;
  END;

 The toText method returns a TEXT representation of the entire
   string.  It should be avoided for very large strings.  Instead, the
   iterate method should be used to access large strings one line at a
   time.


   The numLines method returns the number of lines in the string.  If
   the last line does not have a terminating newline character, it still
   counts as a line.


   The iterate method constructs an iterator that accesses the
   individual lines of the string in sequence.  Each call to the
   Iterator's next method sets the VAR parameter to the next
   line of the string, and returns TRUE.  If there are no more
   lines, next returns FALSE.


   Each returned line includes its terminating newline, if any.  The
   last line won't necessarily end with a newline. 


PROCEDURE FromText(text: TEXT): T;

 Construct an RCSString.T from the given TEXT. 

END RCSString.