--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/IRStackCount.st	Wed Jun 11 14:54:42 2008 +0000
@@ -0,0 +1,125 @@
+"{ Package: 'stx:goodies/newcompiler' }"
+
+Object subclass:#IRStackCount
+	instanceVariableNames:'start position length'
+	classVariableNames:''
+	poolDictionaries:''
+	category:'NewCompiler-Bytecode'
+!
+
+IRStackCount comment:'This keeps track of the stack count for the BytecodeGenerator.'
+!
+
+
+!IRStackCount class methodsFor:'instance creation'!
+
+new
+
+	^ super new startAt: 0
+! !
+
+!IRStackCount class methodsFor:'as yet unclassified'!
+
+startAt: pos
+
+	^ super new startAt: pos
+! !
+
+!IRStackCount methodsFor:'affecting'!
+
+pop
+
+	^ self pop: 1
+!
+
+pop: n
+
+	(position _ position - n) "< 0 
+		ifTrue: [self error: 'Parse stack underflow']"
+!
+
+push
+
+	^ self push: 1
+!
+
+push: n
+
+	(position _ position + n) > length 
+		ifTrue: [length _ position]
+! !
+
+!IRStackCount methodsFor:'comparing'!
+
+= other
+
+	^ self class == other class 
+	  and: [start = other start
+	  and: [position = other position
+	  and: [length = other size]]]
+!
+
+hash
+
+	^ position hash bitXor: (length hash bitXor: start hash)
+! !
+
+!IRStackCount methodsFor:'error handling'!
+
+errorStackOutOfSync: aStackCount 
+	self error: 'stack not in sync!!'.
+! !
+
+!IRStackCount methodsFor:'initialize'!
+
+startAt: pos
+
+	start _ position _ length _ pos
+! !
+
+!IRStackCount methodsFor:'printing'!
+
+printOn: aStream
+	
+	super printOn: aStream.
+	aStream
+		nextPutAll: ' start '; print: start;
+		nextPutAll: ' stop '; print: position;
+		nextPutAll: ' max '; print: length.
+! !
+
+!IRStackCount methodsFor:'results'!
+
+length
+
+	^length
+!
+
+linkTo: stackOrNil
+
+	stackOrNil ifNil: [^ self class startAt: self position].
+	^ self position = stackOrNil start
+		ifTrue: [stackOrNil]
+		ifFalse: [self errorStackOutOfSync: stackOrNil]
+!
+
+position
+
+	^position
+!
+
+size
+
+	^length
+!
+
+start
+
+	^ start
+! !
+
+!IRStackCount class methodsFor:'documentation'!
+
+version
+    ^'$Id$'
+! !