Implement pack file deltification

src/FileSystem-Git.package/GitDeltaCreator.class/class/createFor.basedOn..st

@@ -0,0 +1,6 @@
+instance creation
+createFor: aCollection basedOn: aDeltaIndex
+	^ (self
+		withDeltaIndex: aDeltaIndex
+		target: aCollection)
+		create

src/FileSystem-Git.package/GitDeltaCreator.class/class/createFor.basedOn.maxSize..st

@@ -0,0 +1,7 @@
+instance creation
+createFor: aCollection basedOn: aDeltaIndex maxSize: aNumber
+	^ (self
+		withDeltaIndex: aDeltaIndex
+		target: aCollection
+		maxSize: aNumber)
+		create

src/FileSystem-Git.package/GitDeltaCreator.class/class/maxOperationSize.st

@@ -0,0 +1,3 @@
+constants
+maxOperationSize
+	^ GitDeltaRabinHasher window + 18

src/FileSystem-Git.package/GitDeltaCreator.class/class/withDeltaIndex.target..st

@@ -0,0 +1,6 @@
+instance creation
+withDeltaIndex: aDeltaIndex target: aCollection
+	^ self new
+		deltaIndex: aDeltaIndex;
+		target: aCollection;
+		yourself

src/FileSystem-Git.package/GitDeltaCreator.class/class/withDeltaIndex.target.maxSize..st

@@ -0,0 +1,5 @@
+instance creation
+withDeltaIndex: aDeltaIndex target: aCollection maxSize: aNumber
+	^ (self withDeltaIndex: aDeltaIndex target: aCollection)
+		maxSize: aNumber;
+		yourself

src/FileSystem-Git.package/GitDeltaCreator.class/instance/checkMaxSize.st

@@ -0,0 +1,4 @@
+as yet unclassified
+checkMaxSize
+	(self hasMaxSize and: [self output size >= self maxSize])
+		ifTrue: [self output: nil].

src/FileSystem-Git.package/GitDeltaCreator.class/instance/create.st

@@ -0,0 +1,12 @@
+as yet unclassified
+create
+	self
+		initializeHasher;
+		createOutput;
+		writeSourceSize;
+		writeTargetSize;
+		writeInsertionsWhileInitializingHashValue;
+		mainLoop;
+		ensureInsertionCountIsWritten;
+		checkMaxSize.
+	^ self output

src/FileSystem-Git.package/GitDeltaCreator.class/instance/createOutput.st

@@ -0,0 +1,7 @@
+as yet unclassified
+createOutput
+	| initialSize |
+	initialSize := 8192.
+	(self hasMaxSize and: [initialSize >= self maxSize])
+		ifTrue: [initialSize := self maxSize + self class maxOperationSize + 1].
+	self output: (OrderedCollection new: initialSize).

src/FileSystem-Git.package/GitDeltaCreator.class/instance/deltaIndex..st

@@ -0,0 +1,3 @@
+accessing
+deltaIndex: anObject
+	deltaIndex := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/deltaIndex.st

@@ -0,0 +1,3 @@
+accessing
+deltaIndex
+	^ deltaIndex

src/FileSystem-Git.package/GitDeltaCreator.class/instance/ensureInsertionCountIsWritten.st

@@ -0,0 +1,3 @@
+as yet unclassified
+ensureInsertionCountIsWritten
+	self hasInsertion ifTrue: [self writeInsertionCount].

src/FileSystem-Git.package/GitDeltaCreator.class/instance/erase.st

@@ -0,0 +1,3 @@
+as yet unclassified
+erase
+	self output removeLast.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/eraseSlotForInsertionCount.st

@@ -0,0 +1,3 @@
+as yet unclassified
+eraseSlotForInsertionCount
+	self erase.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/expandMatchBackwards.st

@@ -0,0 +1,14 @@
+as yet unclassified
+expandMatchBackwards
+	self hasInsertion ifFalse: [^ self].
+	[self matchIndex > 1 and: [(self source at: self matchIndex - 1) = (self target at: self targetIndex - 1)]]
+		whileTrue: [
+			self matchSize: self matchSize + 1.
+			self matchIndex: self matchIndex - 1.
+			self targetIndex: self targetIndex - 1.
+			self erase.
+			self insertionCount: self insertionCount - 1.
+			self hasInsertion ifFalse: [
+				self eraseSlotForInsertionCount.
+				^ self]].
+	self writeInsertionCount.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/findMatch.st

@@ -0,0 +1,21 @@
+as yet unclassified
+findMatch
+	self matchSize < 4096 ifFalse: [^ self].
+	self hasher addRollingValueAt: self targetIndex.
+	self deltaIndex entriesWithHashValue: self hasher hashValue do: [:entry |
+		| currentSource sourceRestSize currentTarget newMatchSize |
+		currentSource := entry index.
+		currentTarget := self targetIndex.
+		sourceRestSize := self source size + 1 - currentSource
+				clampHigh: self target size + 1 - currentTarget.
+		sourceRestSize < self matchSize ifTrue: [^ self].
+		[sourceRestSize > 0 and: [(self source at: currentSource) = (self target at: currentTarget)]] whileTrue: [
+			sourceRestSize := sourceRestSize - 1.
+			currentSource := currentSource + 1.
+			currentTarget := currentTarget + 1].
+		newMatchSize := currentSource - entry index.
+		self matchSize <  newMatchSize ifTrue: [
+			self
+				matchSize: newMatchSize;
+				matchIndex: entry index.
+			self matchSize >= 4096 ifTrue: [^ self]]].

src/FileSystem-Git.package/GitDeltaCreator.class/instance/handleMatch.st

@@ -0,0 +1,8 @@
+as yet unclassified
+handleMatch
+	self matchSize < 4
+		ifTrue: [self insertOne]
+		ifFalse: [self
+					expandMatchBackwards;
+					writeCopy;
+					reinitializeHashValue].

src/FileSystem-Git.package/GitDeltaCreator.class/instance/hasInsertion.st

@@ -0,0 +1,3 @@
+as yet unclassified
+hasInsertion
+	^ self insertionCount > 0

src/FileSystem-Git.package/GitDeltaCreator.class/instance/hasMaxSize.st

@@ -0,0 +1,3 @@
+as yet unclassified
+hasMaxSize
+	^ self maxSize isZero not

src/FileSystem-Git.package/GitDeltaCreator.class/instance/hasher..st

@@ -0,0 +1,3 @@
+accessing
+hasher: anObject
+	hasher := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/hasher.st

@@ -0,0 +1,3 @@
+accessing
+hasher
+	^ hasher

src/FileSystem-Git.package/GitDeltaCreator.class/instance/initialize.st

@@ -0,0 +1,9 @@
+as yet unclassified
+initialize
+	super initialize.
+	self
+		maxSize: 0;
+		targetIndex: 1;
+		insertionCount: 0;
+		matchIndex: 1;
+		matchSize: 0.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/initializeHasher.st

@@ -0,0 +1,3 @@
+as yet unclassified
+initializeHasher
+	self hasher: (GitDeltaRabinHasher on: self target).

src/FileSystem-Git.package/GitDeltaCreator.class/instance/insertOne.st

@@ -0,0 +1,7 @@
+accessing
+insertOne
+	self hasInsertion ifFalse: [self skipSlotForInsertionCount].
+	self writeInsertion.
+	self targetIndex: self targetIndex + 1.
+	self insertionCount = 16r7f ifTrue: [self writeInsertionCount].
+	self matchSize: 0.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/insertionCount..st

@@ -0,0 +1,3 @@
+accessing
+insertionCount: anObject
+	insertionCount := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/insertionCount.st

@@ -0,0 +1,3 @@
+accessing
+insertionCount
+	^ insertionCount

src/FileSystem-Git.package/GitDeltaCreator.class/instance/isAborted.st

@@ -0,0 +1,3 @@
+as yet unclassified
+isAborted
+	^ self output isNil

src/FileSystem-Git.package/GitDeltaCreator.class/instance/isAtEnd.st

@@ -0,0 +1,3 @@
+as yet unclassified
+isAtEnd
+	^ self targetIndex > self target size

src/FileSystem-Git.package/GitDeltaCreator.class/instance/mainLoop.st

@@ -0,0 +1,8 @@
+as yet unclassified
+mainLoop
+	[self isAtEnd] whileFalse: [
+		self
+			findMatch;
+			handleMatch;
+			checkMaxSize.
+		self isAborted ifTrue: [^ self]].

src/FileSystem-Git.package/GitDeltaCreator.class/instance/matchIndex..st

@@ -0,0 +1,3 @@
+accessing
+matchIndex: anObject
+	matchIndex := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/matchIndex.st

@@ -0,0 +1,3 @@
+accessing
+matchIndex
+	^ matchIndex

src/FileSystem-Git.package/GitDeltaCreator.class/instance/matchSize..st

@@ -0,0 +1,3 @@
+accessing
+matchSize: anObject
+	matchSize := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/matchSize.st

@@ -0,0 +1,3 @@
+accessing
+matchSize
+	^ matchSize

src/FileSystem-Git.package/GitDeltaCreator.class/instance/maxSize..st

@@ -0,0 +1,3 @@
+accessing
+maxSize: anObject
+	maxSize := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/maxSize.st

@@ -0,0 +1,3 @@
+accessing
+maxSize
+	^ maxSize

src/FileSystem-Git.package/GitDeltaCreator.class/instance/output..st

@@ -0,0 +1,3 @@
+accessing
+output: anObject
+	output := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/output.st

@@ -0,0 +1,3 @@
+accessing
+output
+	^ output

src/FileSystem-Git.package/GitDeltaCreator.class/instance/read.st

@@ -0,0 +1,3 @@
+as yet unclassified
+read
+	^ self target at: self targetIndex

src/FileSystem-Git.package/GitDeltaCreator.class/instance/reinitializeHashValue.st

@@ -0,0 +1,4 @@
+as yet unclassified
+reinitializeHashValue
+	self matchSize < 4096 ifFalse: [^ self].
+	self hasher hashFirstWindowAt: self targetIndex - self hasher class window.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/skipSlotForInsertionCount.st

@@ -0,0 +1,4 @@
+as yet unclassified
+skipSlotForInsertionCount
+	"placeholder that will be overwritten or easy to find during debugging"
+	self write: -1.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/skipSlotForOperation.st

@@ -0,0 +1,4 @@
+as yet unclassified
+skipSlotForOperation
+	"placeholder that will be overwritten or easy to find during debugging"
+	self write: -1.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/source.st

@@ -0,0 +1,3 @@
+accessing
+source
+	^ self deltaIndex source

src/FileSystem-Git.package/GitDeltaCreator.class/instance/target..st

@@ -0,0 +1,3 @@
+accessing
+target: anObject
+	target := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/target.st

@@ -0,0 +1,3 @@
+accessing
+target
+	^ target

src/FileSystem-Git.package/GitDeltaCreator.class/instance/targetIndex..st

@@ -0,0 +1,3 @@
+accessing
+targetIndex: anObject
+	targetIndex := anObject

src/FileSystem-Git.package/GitDeltaCreator.class/instance/targetIndex.st

@@ -0,0 +1,3 @@
+accessing
+targetIndex
+	^ targetIndex

src/FileSystem-Git.package/GitDeltaCreator.class/instance/write..st

@@ -0,0 +1,3 @@
+as yet unclassified
+write: anInteger
+	self output addLast: anInteger.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/writeCopy.st

@@ -0,0 +1,21 @@
+as yet unclassified
+writeCopy
+	| left operationIndex operation offset |
+	left := self matchSize - 16r10000 clampLow: 0.
+	self matchSize: self matchSize - left.
+	self skipSlotForOperation.
+	operationIndex := self output size.
+	operation := 16r80.
+	offset := self matchIndex - 1.
+	(offset bitAnd: 16r000000ff) > 0 ifTrue: [operation := operation bitOr: 16r01. self write: (offset"bitShift: 0")].
+	(offset bitAnd: 16r0000ff00) > 0 ifTrue: [operation := operation bitOr: 16r02. self write: (offset bitShift: -8)].
+	(offset bitAnd: 16r00ff0000) > 0 ifTrue: [operation := operation bitOr: 16r04. self write: (offset bitShift: -16)].
+	(offset bitAnd: 16rff000000) > 0 ifTrue: [operation := operation bitOr: 16r08. self write: (offset bitShift: -24)].
+	(self matchSize bitAnd: 16r00ff) > 0 ifTrue: [operation := operation bitOr: 16r10. self write: (self matchSize"bitShift: 0")].
+	(self matchSize bitAnd: 16rff00) > 0 ifTrue: [operation := operation bitOr: 16r20. self write: (self matchSize bitShift: -8)].
+	self output at: operationIndex put: operation.
+
+	self targetIndex: self targetIndex + self matchSize.
+	self matchIndex: self matchIndex + self matchSize.
+	self matchSize: left.
+	self matchIndex - 1 > 16rffffffff ifTrue: [self matchSize: 0].

src/FileSystem-Git.package/GitDeltaCreator.class/instance/writeInsertion.st

@@ -0,0 +1,4 @@
+as yet unclassified
+writeInsertion
+	self write: self read.
+	self insertionCount: self insertionCount + 1.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/writeInsertionCount.st

@@ -0,0 +1,4 @@
+as yet unclassified
+writeInsertionCount
+	self output at: self output size - self insertionCount put: self insertionCount.
+	self insertionCount: 0.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/writeInsertionsWhileInitializingHashValue.st

@@ -0,0 +1,8 @@
+as yet unclassified
+writeInsertionsWhileInitializingHashValue
+	self skipSlotForInsertionCount.
+	self hasher class window timesRepeat: [
+		self isAtEnd ifTrue: [^ self].
+		self writeInsertion.
+		self hasher addFirstWindowValueAt: self targetIndex.
+		self targetIndex: self targetIndex + 1].

src/FileSystem-Git.package/GitDeltaCreator.class/instance/writeSourceSize.st

@@ -0,0 +1,3 @@
+as yet unclassified
+writeSourceSize
+	self writeVariableSizeInteger: self source size.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/writeTargetSize.st

@@ -0,0 +1,3 @@
+as yet unclassified
+writeTargetSize
+	self writeVariableSizeInteger: self target size.

src/FileSystem-Git.package/GitDeltaCreator.class/instance/writeVariableSizeInteger..st

@@ -0,0 +1,8 @@
+as yet unclassified
+writeVariableSizeInteger: anInteger
+	| left |
+	left := anInteger.
+	[left >= 16r80] whileTrue: [
+		self write: (left bitOr: 16r80).
+		left := left bitShift: -7].
+	self write: left.