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decodeLiteral and decodeDistance are no longer separate functions.

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This commit is contained in:
Timofey Solomko
2016-12-16 20:46:28 +03:00
parent 1df18966e5
commit b970fb142c
1 changed files with 55 additions and 55 deletions
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Sources/LZMA.swift
+55 -55
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@@ -271,7 +271,7 @@ public final class LZMA: DecompressionAlgorithm {
var dictionarySize = pointerData.intFromAlingedBytes(count: 4)
dictionarySize = dictionarySize < (1 << 12) ? 1 << 12 : dictionarySize
print("lc: \(lc), lp: \(lp), pb: \(pb), dictionarySize: \(dictionarySize)")
// print("lc: \(lc), lp: \(lp), pb: \(pb), dictionarySize: \(dictionarySize)")
/// Size of uncompressed data. -1 means it is unknown.
var uncompressedSize = pointerData.intFromAlingedBytes(count: 8)
@@ -281,7 +281,7 @@ public final class LZMA: DecompressionAlgorithm {
var out: [UInt8] = uncompressedSize == -1 ? [] : Array(repeating: 0, count: uncompressedSize)
var outIndex = uncompressedSize == -1 ? -1 : 0
print("uncompressedSize: \(uncompressedSize)")
// print("uncompressedSize: \(uncompressedSize)")
let outWindow = OutWindow(dictSize: dictionarySize)
@@ -312,56 +312,6 @@ public final class LZMA: DecompressionAlgorithm {
var rep3 = 0
var state = 0
func decodeLiteral(_ state: Int, _ rep0: Int) {
let prevByte = outWindow.isEmpty ? 0 : outWindow.byte(at: 1)
// TODO: Something is not quite right.
var symbol = 1
let litState = ((outWindow.totalPosition & ((1 << lp.toInt()) - 1)) << lc.toInt()) + (prevByte >> (8 - lc)).toInt()
let probsIndex = 0x300 * litState
if state >= 7 {
var matchByte = outWindow.byte(at: rep0 + 1)
repeat {
let matchBit = ((matchByte >> 7) & 1).toInt()
matchByte <<= 1
let bit = rangeDecoder.decode(bitWithProb: &literalProbs[((1 + matchBit) << 8) + symbol],
pointerData: &pointerData)
symbol = (symbol << 1) | bit
if matchBit != bit {
break
}
} while symbol < 0x100
}
while symbol < 0x100 {
symbol = (symbol << 1) | rangeDecoder.decode(bitWithProb: &literalProbs[symbol], pointerData: &pointerData)
}
let byte = (symbol - 0x100).toUInt8()
outWindow.put(byte, &out, &outIndex, &uncompressedSize)
}
func decodeDistance(_ len: Int) -> Int {
var lenState = len
if lenState > Constants.numLenToPosStates - 1 {
lenState = Constants.numLenToPosStates - 1
}
let posSlot = posSlotDecoder[lenState].decode(with: &rangeDecoder, pointerData: &pointerData)
if posSlot < 4 {
return posSlot
}
let numDirectBits = (posSlot >> 1) - 1
var dist = ((2 | (posSlot & 1)) << numDirectBits)
if posSlot < Constants.endPosModelIndex {
// TODO: Probably incorrect first argument.
dist += bitTreeReverseDecode(probs: &posDecoders, bits: numDirectBits, rangeDecoder: &rangeDecoder, pointerData: &pointerData)
} else {
dist += rangeDecoder.decode(directBits: (numDirectBits - Constants.numAlignBits) << Constants.numAlignBits,
pointerData: &pointerData)
dist += alignDecoder.reverseDecode(with: &rangeDecoder, pointerData: &pointerData)
}
return dist
}
// Main decoding cycle.
while true {
// If uncompressed size was defined and everything is unpacked then stop.
@@ -376,7 +326,33 @@ public final class LZMA: DecompressionAlgorithm {
if uncompressedSize == 0 {
// TODO: throw error
}
decodeLiteral(state, rep0)
// DECODE LITERAL:
let prevByte = outWindow.isEmpty ? 0 : outWindow.byte(at: 1)
// TODO: Something is not quite right.
var symbol = 1
let litState = ((outWindow.totalPosition & ((1 << lp.toInt()) - 1)) << lc.toInt()) + (prevByte >> (8 - lc)).toInt()
let probsIndex = 0x300 * litState
if state >= 7 {
var matchByte = outWindow.byte(at: rep0 + 1)
repeat {
let matchBit = ((matchByte >> 7) & 1).toInt()
matchByte <<= 1
let bit = rangeDecoder.decode(bitWithProb: &literalProbs[((1 + matchBit) << 8) + symbol],
pointerData: &pointerData)
symbol = (symbol << 1) | bit
if matchBit != bit {
break
}
} while symbol < 0x100
}
while symbol < 0x100 {
symbol = (symbol << 1) | rangeDecoder.decode(bitWithProb: &literalProbs[symbol], pointerData: &pointerData)
}
let byte = (symbol - 0x100).toUInt8()
outWindow.put(byte, &out, &outIndex, &uncompressedSize)
// END.
if state < 4 {
state = 0
} else if (state < 10) {
@@ -384,7 +360,7 @@ public final class LZMA: DecompressionAlgorithm {
} else {
state -= 6
}
uncompressedSize -= 1
continue
}
@@ -428,7 +404,31 @@ public final class LZMA: DecompressionAlgorithm {
rep1 = rep0
len = lenDecoder.decode(with: &rangeDecoder, posState: posState, pointerData: &pointerData)
state = state < 7 ? 7 : 10
rep0 = decodeDistance(len)
// DECODE DISTANCE:
var lenState = len
if lenState > Constants.numLenToPosStates - 1 {
lenState = Constants.numLenToPosStates - 1
}
let posSlot = posSlotDecoder[lenState].decode(with: &rangeDecoder, pointerData: &pointerData)
if posSlot < 4 {
rep0 = posSlot
} else {
let numDirectBits = (posSlot >> 1) - 1
var dist = ((2 | (posSlot & 1)) << numDirectBits)
if posSlot < Constants.endPosModelIndex {
// TODO: Probably incorrect first argument.
dist += bitTreeReverseDecode(probs: &posDecoders, bits: numDirectBits, rangeDecoder: &rangeDecoder, pointerData: &pointerData)
} else {
dist += rangeDecoder.decode(directBits: (numDirectBits - Constants.numAlignBits) << Constants.numAlignBits,
pointerData: &pointerData)
dist += alignDecoder.reverseDecode(with: &rangeDecoder, pointerData: &pointerData)
}
rep0 = dist
}
// END.
// Check if finished marker is encoutered.
if rep0 == 0xFFFFFFFF {
if rangeDecoder.isFinishedOK {