| /* |
| * LZMACoder |
| * |
| * Authors: Lasse Collin <lasse.collin@tukaani.org> |
| * Igor Pavlov <http://7-zip.org/> |
| * |
| * This file has been put into the public domain. |
| * You can do whatever you want with this file. |
| */ |
| |
| package org.tukaani.xz.lzma; |
| |
| import org.tukaani.xz.rangecoder.RangeCoder; |
| |
| abstract class LZMACoder { |
| static final int POS_STATES_MAX = 1 << 4; |
| |
| static final int MATCH_LEN_MIN = 2; |
| static final int MATCH_LEN_MAX = MATCH_LEN_MIN + LengthCoder.LOW_SYMBOLS |
| + LengthCoder.MID_SYMBOLS |
| + LengthCoder.HIGH_SYMBOLS - 1; |
| |
| static final int DIST_STATES = 4; |
| static final int DIST_SLOTS = 1 << 6; |
| static final int DIST_MODEL_START = 4; |
| static final int DIST_MODEL_END = 14; |
| static final int FULL_DISTANCES = 1 << (DIST_MODEL_END / 2); |
| |
| static final int ALIGN_BITS = 4; |
| static final int ALIGN_SIZE = 1 << ALIGN_BITS; |
| static final int ALIGN_MASK = ALIGN_SIZE - 1; |
| |
| static final int REPS = 4; |
| |
| final int posMask; |
| |
| final int[] reps = new int[REPS]; |
| final State state = new State(); |
| |
| final short[][] isMatch = new short[State.STATES][POS_STATES_MAX]; |
| final short[] isRep = new short[State.STATES]; |
| final short[] isRep0 = new short[State.STATES]; |
| final short[] isRep1 = new short[State.STATES]; |
| final short[] isRep2 = new short[State.STATES]; |
| final short[][] isRep0Long = new short[State.STATES][POS_STATES_MAX]; |
| final short[][] distSlots = new short[DIST_STATES][DIST_SLOTS]; |
| final short[][] distSpecial = { new short[2], new short[2], |
| new short[4], new short[4], |
| new short[8], new short[8], |
| new short[16], new short[16], |
| new short[32], new short[32] }; |
| final short[] distAlign = new short[ALIGN_SIZE]; |
| |
| static final int getDistState(int len) { |
| return len < DIST_STATES + MATCH_LEN_MIN |
| ? len - MATCH_LEN_MIN |
| : DIST_STATES - 1; |
| } |
| |
| LZMACoder(int pb) { |
| posMask = (1 << pb) - 1; |
| } |
| |
| void reset() { |
| reps[0] = 0; |
| reps[1] = 0; |
| reps[2] = 0; |
| reps[3] = 0; |
| state.reset(); |
| |
| for (int i = 0; i < isMatch.length; ++i) |
| RangeCoder.initProbs(isMatch[i]); |
| |
| RangeCoder.initProbs(isRep); |
| RangeCoder.initProbs(isRep0); |
| RangeCoder.initProbs(isRep1); |
| RangeCoder.initProbs(isRep2); |
| |
| for (int i = 0; i < isRep0Long.length; ++i) |
| RangeCoder.initProbs(isRep0Long[i]); |
| |
| for (int i = 0; i < distSlots.length; ++i) |
| RangeCoder.initProbs(distSlots[i]); |
| |
| for (int i = 0; i < distSpecial.length; ++i) |
| RangeCoder.initProbs(distSpecial[i]); |
| |
| RangeCoder.initProbs(distAlign); |
| } |
| |
| |
| abstract class LiteralCoder { |
| private final int lc; |
| private final int literalPosMask; |
| |
| LiteralCoder(int lc, int lp) { |
| this.lc = lc; |
| this.literalPosMask = (1 << lp) - 1; |
| } |
| |
| final int getSubcoderIndex(int prevByte, int pos) { |
| int low = prevByte >> (8 - lc); |
| int high = (pos & literalPosMask) << lc; |
| return low + high; |
| } |
| |
| |
| abstract class LiteralSubcoder { |
| final short[] probs = new short[0x300]; |
| |
| void reset() { |
| RangeCoder.initProbs(probs); |
| } |
| } |
| } |
| |
| |
| abstract class LengthCoder { |
| static final int LOW_SYMBOLS = 1 << 3; |
| static final int MID_SYMBOLS = 1 << 3; |
| static final int HIGH_SYMBOLS = 1 << 8; |
| |
| final short[] choice = new short[2]; |
| final short[][] low = new short[POS_STATES_MAX][LOW_SYMBOLS]; |
| final short[][] mid = new short[POS_STATES_MAX][MID_SYMBOLS]; |
| final short[] high = new short[HIGH_SYMBOLS]; |
| |
| void reset() { |
| RangeCoder.initProbs(choice); |
| |
| for (int i = 0; i < low.length; ++i) |
| RangeCoder.initProbs(low[i]); |
| |
| for (int i = 0; i < low.length; ++i) |
| RangeCoder.initProbs(mid[i]); |
| |
| RangeCoder.initProbs(high); |
| } |
| } |
| } |