"{ Package: 'stx:libjava' }"

Object subclass:#JavaNativeMemory

	instanceVariableNames:'addresses chunks'

	classVariableNames:''

	poolDictionaries:''

	category:'Languages-Java-Support'

!

!JavaNativeMemory class methodsFor:'instance creation'!

new

    "return an initialized instance"

    ^ self basicNew initialize.

! !

!JavaNativeMemory methodsFor:'accessing'!

byteAt:address

    |i chunk offset|

    addresses size == 0 ifTrue:[

        self errorAccessingUnallocatedMemory:address

    ].

    i := 1.

    [

        i <= (addresses size - 1) and:[ (addresses at:i + 1) <= address ]

    ] whileTrue:[ i := i + 1 ].

    offset := address - (addresses at:i).

    chunk := chunks at:i.

    (offset > chunk size) ifTrue:[

        self errorAccessingUnallocatedMemory:address

    ].

    ^chunk at: offset + 1

    "Created: / 09-12-2010 / 17:32:45 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

longAt:address put:value 

    |i chunk offset|

    addresses size == 0 ifTrue:[

        self errorAccessingUnallocatedMemory:address

    ].

    i := 1.

    [

        i <= (addresses size - 1) and:[ (addresses at:i + 1) <= address ]

    ] whileTrue:[ i := i + 1 ].

    offset := address - (addresses at:i).

    chunk := chunks at:i.

    (offset > chunk size) ifTrue:[

        self errorAccessingUnallocatedMemory:address

    ].

    chunk longLongAt: offset + 1 put: value

    "Created: / 09-12-2010 / 17:32:02 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!JavaNativeMemory methodsFor:'allocation/deallocation'!

free: address

    "Frees the memory"

    | index |

    address = 0 ifTrue:[^self].

    index := addresses 

                indexOf: address 

                ifAbsent:[self error:'Never allocated'].

    (chunks at: index) 

                ifNil:[self error: 'Freed twice'].

    chunks at: index put: nil.

    "Created: / 07-12-2010 / 23:33:22 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

malloc: size

    "Allocate new chunk of memory, size bytes long"

    | address |

    self assert: addresses size == chunks size.

    addresses size > 0 

            ifTrue: [address := addresses last + chunks last size ]

            ifFalse:[address := 0].

    address := address + (Random nextIntegerBetween: 128 and: 256).

    addresses add: address.

    chunks add: (ByteArray new: size).

    ^address

    "Created: / 07-12-2010 / 23:25:09 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!JavaNativeMemory methodsFor:'error reporting'!

errorAccessingUnallocatedMemory:arg

    self shouldImplement

    "Created: / 07-12-2010 / 23:40:01 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!JavaNativeMemory methodsFor:'initialization'!

initialize

    "Invoked when a new instance is created."

    addresses := OrderedCollection new.

    chunks := OrderedCollection new.

    "/ super initialize.   -- commented since inherited method does nothing

    "Modified: / 07-12-2010 / 23:09:04 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!JavaNativeMemory class methodsFor:'documentation'!

version_SVN

    ^ '$Id$'

! !