The Trunk: Compression-nice.12.mcz

Nicolas Cellier uploaded a new version of Compression to project The Trunk:
http://source.squeak.org/trunk/Compression-nice.12.mcz

==================== Summary ====================

Name: Compression-nice.12
Author: nice
Time: 18 December 2009, 9:07:50 am
UUID: b9ac9a27-ed19-4a28-9d18-0911f756a263
Ancestors: Compression-nice.11

Cosmetic changes from pharo
- temps local to block
- use ifNil:

=============== Diff against Compression-nice.11 ===============

Item was changed:
  ----- Method: Archive>>addTree:removingFirstCharacters:match: (in category 'archive operations') -----
  addTree: aFileNameOrDirectory removingFirstCharacters: n match: aBlock
+ | dir fullPath relativePath |
- | dir newMember fullPath relativePath |
  dir := (aFileNameOrDirectory isString)
  ifTrue: [ FileDirectory on: aFileNameOrDirectory ]
  ifFalse: [ aFileNameOrDirectory ].
  fullPath := dir pathName, dir slash.
  relativePath := fullPath copyFrom: n + 1 to: fullPath size.
  (dir entries select: [ :entry | aBlock value: entry])
+ do: [ :ea | | fullName newMember |
- do: [ :ea | | fullName |
  fullName := fullPath, ea name.
  newMember := ea isDirectory
  ifTrue: [ self memberClass newFromDirectory: fullName ]
  ifFalse: [ self memberClass newFromFile: fullName ].
  newMember localFileName: relativePath, ea name.
  self addMember: newMember.
  ea isDirectory ifTrue: [ self addTree: fullName removingFirstCharacters: n match: aBlock].
  ].
  !

Item was changed:
  ----- Method: ZipEncoderNode>>encodeBitLength:from: (in category 'encoding') -----
  encodeBitLength: blCounts from: aTree
  | index |
  "Note: If bitLength is not nil then the tree must be broken"
+ bitLength ifNotNil: [self error:'Huffman tree is broken'].
+ parent  
+ ifNil: [bitLength := 0]
+ ifNotNil: [bitLength := parent bitLength + 1].
- bitLength == nil ifFalse:[self error:'Huffman tree is broken'].
- parent = nil
- ifTrue:[bitLength := 0]
- ifFalse:[bitLength := parent bitLength + 1].
  self isLeaf ifTrue:[
  index := bitLength + 1.
  blCounts at: index put: (blCounts at: index) + 1.
  ] ifFalse:[
  left encodeBitLength: blCounts from: aTree.
  right encodeBitLength: blCounts from: aTree.
  ].!

Item was changed:
  ----- Method: ZipWriteStream>>flushBlock: (in category 'encoding') -----
  flushBlock: lastBlock
  "Send the current block"
  | lastFlag bitsRequired method bitsSent
  storedLength fixedLength dynamicLength
  blTree lTree dTree blBits blFreq |
 
  lastFlag := lastBlock ifTrue:[1] ifFalse:[0].
 
  "Compute the literal/length and distance tree"
  lTree := ZipEncoderTree buildTreeFrom: literalFreq maxDepth: MaxBits.
  dTree := ZipEncoderTree buildTreeFrom: distanceFreq maxDepth: MaxBits.
 
  "Compute the bit length tree"
  blBits := lTree bitLengths, dTree bitLengths.
  blFreq := WordArray new: MaxBitLengthCodes.
  self scanBitLengths: blBits into: blFreq.
  blTree := ZipEncoderTree buildTreeFrom: blFreq maxDepth: MaxBitLengthBits.
 
  "Compute the bit length for the current block.
  Note: Most of this could be computed on the fly but it's getting
  really ugly in this case so we do it afterwards."
  storedLength := self storedBlockSize.
  fixedLength := self fixedBlockSizeFor: lTree and: dTree.
  dynamicLength := self dynamicBlockSizeFor: lTree and: dTree
  using: blTree and: blFreq.
  VerboseLevel > 1 ifTrue:[
  Transcript cr; show:'Block sizes (S/F/D):';
  space; print: storedLength // 8;
  nextPut:$/; print: fixedLength // 8;
  nextPut:$/; print: dynamicLength // 8; space; endEntry].
 
  "Check which method to use"
  method := self forcedMethod.
+ method ifNil:[
- method == nil ifTrue:[
  method := (storedLength < fixedLength and:[storedLength < dynamicLength])
  ifTrue:[#stored]
  ifFalse:[fixedLength < dynamicLength ifTrue:[#fixed] ifFalse:[#dynamic]]].
  (method == #stored and:[blockStart < 0]) ifTrue:[
  "Cannot use #stored if the block is not available"
  method := fixedLength < dynamicLength ifTrue:[#fixed] ifFalse:[#dynamic]].
 
  bitsSent := encoder bitPosition. "# of bits sent before this block"
  bitsRequired := nil.
 
  (method == #stored) ifTrue:[
  VerboseLevel > 0 ifTrue:[Transcript show:'S'].
  bitsRequired := storedLength.
  encoder nextBits: 3 put: StoredBlock << 1 + lastFlag.
  self sendStoredBlock].
 
  (method == #fixed) ifTrue:[
  VerboseLevel > 0 ifTrue:[Transcript show:'F'].
  bitsRequired := fixedLength.
  encoder nextBits: 3 put: FixedBlock << 1 + lastFlag.
  self sendFixedBlock].
 
  (method == #dynamic) ifTrue:[
  VerboseLevel > 0 ifTrue:[Transcript show:'D'].
  bitsRequired := dynamicLength.
  encoder nextBits: 3 put: DynamicBlock << 1 + lastFlag.
  self sendDynamicBlock: blTree
  literalTree: lTree
  distanceTree: dTree
  bitLengths: blBits].
 
  bitsRequired = (encoder bitPosition - bitsSent)
  ifFalse:[self error:'Bits size mismatch'].
 
  lastBlock
  ifTrue:[self release]
  ifFalse:[self initializeNewBlock].!