classes.struct.packed: adding support for packed structures.

extra/classes/struct/packed/authors.txt

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+John Benediktsson

extra/classes/struct/packed/packed-tests.factor

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+
+USING: alien.c-types classes.struct.packed tools.test words ;
+
+IN: classes.struct.packed
+
+PACKED-STRUCT: abcd
+    { a int }
+    { b int }
+    { c int }
+    { d int }
+    { e short }
+    { f int }
+    { g int }
+    { h int }
+;
+
+[ 30 ] [ \ abcd "struct-size" word-prop ] unit-test

extra/classes/struct/packed/packed.factor

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+! Copyright (C) 2011 John Benediktsson
+! See http://factorcode.org/license.txt for BSD license
+
+USING: accessors alien.c-types classes.struct
+classes.struct.private kernel locals math sequences slots
+words ;
+
+IN: classes.struct.packed
+
+<PRIVATE
+
+CONSTANT: ALIGNMENT 1
+
+GENERIC: compute-packed-offset ( offset class -- offset' )
+
+M: struct-slot-spec compute-packed-offset
+    [ ALIGNMENT 8 * align ] dip
+    [ [ 8 /i ] dip offset<< ] [ type>> heap-size 8 * + ] 2bi ;
+
+M: struct-bit-slot-spec compute-packed-offset
+    [ offset<< ] [ bits>> + ] 2bi ;
+
+: compute-packed-offsets ( slots -- size )
+    0 [ compute-packed-offset ] reduce 8 align 8 /i ;
+
+:: (define-packed-class) ( class slots offsets-quot -- )
+    slots empty? [ struct-must-have-slots ] when
+    class redefine-struct-tuple-class
+    slots make-slots dup check-struct-slots :> slot-specs
+    slot-specs offsets-quot call :> unaligned-size
+    ALIGNMENT :> alignment
+    unaligned-size :> size
+
+    class  slot-specs  size  alignment  c-type-for-class :> c-type
+
+    c-type class typedef
+    class slot-specs define-accessors
+    class size "struct-size" set-word-prop
+    class dup make-struct-prototype "prototype" set-word-prop
+    class (struct-methods) ; inline
+
+: define-packed-struct-class ( class slots -- )
+    [ compute-packed-offsets ] (define-packed-class) ;
+
+PRIVATE>
+
+SYNTAX: PACKED-STRUCT:
+    parse-struct-definition define-packed-struct-class ;
+
+

extra/classes/struct/packed/summary.txt

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+Support for packed structures