S" FICL_WANT_OOP" ENVIRONMENT? drop [if]
\ ** ficl/softwords/classes.fr
\ ** F I C L   2 . 0   C L A S S E S
\ john sadler  1 sep 98
\ Needs oop.fr

.( loading ficl utility classes ) cr
also oop definitions

\ REF subclass holds a pointer to an object. It's
\ mainly for aggregation to help in making data structures.
\
object subclass c-ref
    cell: .class
    cell: .instance

	: get   ( inst class -- refinst refclass )
		drop 2@ ;
	: set   ( refinst refclass inst class -- )
		drop 2! ;
end-class

object subclass c-byte
	char: .payload

	: get  drop c@ ;
	: set  drop c! ;
end-class

object subclass c-2byte
	2 chars: .payload

	: get  drop w@ ;
	: set  drop w! ;
end-class

object subclass c-4byte
	4 chars: .payload

	: get  drop q@ ;
	: set  drop q! ;
end-class


object subclass c-cell
	cell: .payload

	: get  drop @ ;
	: set  drop ! ;
end-class


\ ** C - P T R
\ Base class for pointers to scalars (not objects).
\ Note: use c-ref to make references to objects. C-ptr
\ subclasses refer to untyped quantities of various sizes.

\ Derived classes must specify the size of the thing
\ they point to, and supply get and set methods.

\ All derived classes must define the @size method:
\ @size ( inst class -- addr-units )
\ Returns the size in address units of the thing the pointer
\ refers to.
object subclass c-ptr
    c-cell obj: .addr

    \ get the value of the pointer
    : get-ptr   ( inst class -- addr )
        c-ptr  => .addr
        c-cell => get
    ;

    \ set the pointer to address supplied
    : set-ptr   ( addr inst class -- )
        c-ptr  => .addr
        c-cell => set
    ;

    \ force the pointer to be null
	: clr-ptr
	    0 -rot  c-ptr => .addr  c-cell => set
	;

    \ return flag indicating null-ness
	: ?null     ( inst class -- flag )
	    c-ptr => get-ptr 0=
	;

    \ increment the pointer in place
    : inc-ptr   ( inst class -- )
        2dup 2dup                   ( i c i c i c )
        c-ptr => get-ptr  -rot      ( i c addr i c )
        --> @size  +  -rot          ( addr' i c )
        c-ptr => set-ptr
    ;

    \ decrement the pointer in place
    : dec-ptr    ( inst class -- )
        2dup 2dup                   ( i c i c i c )
        c-ptr => get-ptr  -rot      ( i c addr i c )
        --> @size  -  -rot          ( addr' i c )
        c-ptr => set-ptr
    ;

    \ index the pointer in place
    : index-ptr   { index 2:this -- }
        this --> get-ptr              ( addr )
        this --> @size  index *  +    ( addr' )
        this --> set-ptr
    ;

end-class


\ ** C - C E L L P T R
\ Models a pointer to cell (a 32 or 64 bit scalar).
c-ptr subclass c-cellPtr
    : @size   2drop  1 cells ;
    \ fetch and store through the pointer
	: get   ( inst class -- cell )
        c-ptr => get-ptr @
    ;
	: set   ( value inst class -- )
        c-ptr => get-ptr !
    ;
end-class


\ ** C - 4 B Y T E P T R
\ Models a pointer to a quadbyte scalar
c-ptr subclass c-4bytePtr
    : @size   2drop  4  ;
    \ fetch and store through the pointer
	: get   ( inst class -- value )
        c-ptr => get-ptr q@
    ;
	: set   ( value inst class -- )
        c-ptr => get-ptr q!
    ;
 end-class

\ ** C - 2 B Y T E P T R
\ Models a pointer to a 16 bit scalar
c-ptr subclass c-2bytePtr
    : @size   2drop  2  ;
    \ fetch and store through the pointer
	: get   ( inst class -- value )
        c-ptr => get-ptr w@
    ;
	: set   ( value inst class -- )
        c-ptr => get-ptr w!
    ;
end-class


\ ** C - B Y T E P T R
\ Models a pointer to an 8 bit scalar
c-ptr subclass c-bytePtr
    : @size   2drop  1  ;
    \ fetch and store through the pointer
	: get   ( inst class -- value )
        c-ptr => get-ptr c@
    ;
	: set   ( value inst class -- )
        c-ptr => get-ptr c!
    ;
end-class


previous definitions
[endif]