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out array is now a property of LZMATestDecoder.

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This commit is contained in:
Timofey Solomko
2017-05-01 21:16:38 +03:00
parent 4ca0dba31b
commit 201d7b97fc
2 changed files with 18 additions and 17 deletions
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Sources/LZMA.swift
+2 -1
View File
@@ -84,7 +84,8 @@ public final class LZMA: DecompressionAlgorithm {
let lzmaDecoder = try LZMATestDecoder(&pointerData, lc, pb, lp, dictionarySize)
return try lzmaDecoder.decodeLZMA(&uncompressedSize)
try lzmaDecoder.decodeLZMA(&uncompressedSize)
return lzmaDecoder.out
}
}
Sources/LZMATestDecoder.swift
+16 -16
View File
@@ -52,6 +52,13 @@ final class LZMATestDecoder {
/// Is used to select exact variable from 'IsRep', 'IsRepG0', 'IsRepG1' and 'IsRepG2' arrays.
private var state: Int = 0
/// An array for storing output data
var out: [UInt8] = []
// This array will also serve as dictionary and out window.
private var dictStart = 0
private var dictEnd = 0
init(_ pointerData: inout DataWithPointer, _ lc: UInt8, _ pb: UInt8, _ lp: UInt8,
_ dictionarySize: Int) throws {
self.pointerData = pointerData
@@ -80,18 +87,13 @@ final class LZMATestDecoder {
self.repLenDecoder = LZMALenDecoder(&self.pointerData)
}
func decodeLZMA(_ uncompressedSize: inout Int) throws -> [UInt8] {
func decodeLZMA(_ uncompressedSize: inout Int) throws {
// First, we need to initialize Rande Decoder.
guard let rD = LZMARangeDecoder(&self.pointerData) else {
throw LZMAError.RangeDecoderInitError
}
self.rangeDecoder = rD
/// An array for storing output data
var out: [UInt8] = []
var dictStart = 0
var dictEnd = 0
// Main decoding cycle.
while true {
// If uncompressed size was defined and everything is unpacked then stop.
@@ -107,7 +109,7 @@ final class LZMATestDecoder {
// DECODE LITERAL:
/// Previous literal (zero, if there was none).
let prevByte = dictEnd == 0 ? 0 : out[1 <= dictEnd ? dictEnd - 1 : self.dictionarySize - 1 + dictEnd]
let prevByte = dictEnd == 0 ? 0 : out[1 <= dictEnd ? dictEnd - 1 : dictionarySize - 1 + dictEnd]
/// Decoded symbol. Initial value is 1.
var symbol = 1
/**
@@ -123,7 +125,7 @@ final class LZMATestDecoder {
Byte in output at position that is the `distance` bytes before current position,
where the `distance` is the distance from the latest decoded match.
*/
var matchByte = out[rep0 + 1 <= dictEnd ? dictEnd - rep0 - 1 : self.dictionarySize - rep0 - 1 + dictEnd]
var matchByte = out[rep0 + 1 <= dictEnd ? dictEnd - rep0 - 1 : dictionarySize - rep0 - 1 + dictEnd]
repeat {
let matchBit = ((matchByte >> 7) & 1).toInt()
matchByte <<= 1
@@ -142,7 +144,7 @@ final class LZMATestDecoder {
out.append(byte)
uncompressedSize -= 1
dictEnd += 1
if dictEnd - dictStart == self.dictionarySize {
if dictEnd - dictStart == dictionarySize {
dictStart += 1
}
// END.
@@ -169,11 +171,11 @@ final class LZMATestDecoder {
if rangeDecoder.decode(bitWithProb: &probabilities[241 + (state << LZMAConstants.numPosBitsMax) + posState]) == 0 {
// SHORT REP MATCH CASE
state = state < 7 ? 9 : 11
let byte = out[rep0 + 1 <= dictEnd ? dictEnd - rep0 - 1 : self.dictionarySize - rep0 - 1 + dictEnd]
let byte = out[rep0 + 1 <= dictEnd ? dictEnd - rep0 - 1 : dictionarySize - rep0 - 1 + dictEnd]
out.append(byte)
uncompressedSize -= 1
dictEnd += 1
if dictEnd - dictStart == self.dictionarySize {
if dictEnd - dictStart == dictionarySize {
dictStart += 1
}
continue
@@ -251,23 +253,21 @@ final class LZMATestDecoder {
}
if uncompressedSize == 0 { throw LZMAError.ExceededUncompressedSize }
if rep0 >= dictionarySize || (rep0 > dictEnd && dictEnd < self.dictionarySize) { throw LZMAError.NotEnoughToRepeat }
if rep0 >= dictionarySize || (rep0 > dictEnd && dictEnd < dictionarySize) { throw LZMAError.NotEnoughToRepeat }
}
// Converting from zero-based length of the match to the real one.
len += LZMAConstants.matchMinLen
if uncompressedSize > -1 && uncompressedSize < len { throw LZMAError.RepeatWillExceed }
for _ in 0..<len {
let byte = out[rep0 + 1 <= dictEnd ? dictEnd - rep0 - 1 : self.dictionarySize - rep0 - 1 + dictEnd]
let byte = out[rep0 + 1 <= dictEnd ? dictEnd - rep0 - 1 : dictionarySize - rep0 - 1 + dictEnd]
out.append(byte)
uncompressedSize -= 1
dictEnd += 1
if dictEnd - dictStart == self.dictionarySize {
if dictEnd - dictStart == dictionarySize {
dictStart += 1
}
}
}
return out
}
}