dorkbox.cabParser.decompress.lzx.DecompressLzxTree Maven / Gradle / Ivy
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Parse and extract data from Microsoft LZX compressed .cab files for Java 6+
/*
* Copyright 2012 dorkbox, llc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package dorkbox.cabParser.decompress.lzx;
import dorkbox.cabParser.CorruptCabException;
final class DecompressLzxTree implements LZXConstants {
private int size;
private int[] aa;
int[] LENS;
private int[] a1;
private int[] a2;
private int[] table;
private int b1;
private int b2;
private int b3;
private int b4;
private DecompressLzx decompressor;
private DecompressLzxTree root;
private int[] c1 = new int[17];
private int[] c2 = new int[17];
private int[] c3 = new int[18];
private static final byte[] array = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
DecompressLzxTree(int size, int paramInt2, DecompressLzx decompressor, DecompressLzxTree root) {
this.size = size;
this.b1 = paramInt2;
this.decompressor = decompressor;
this.root = root;
this.b2 = 1 << this.b1;
this.b3 = this.b2 - 1;
this.b4 = 32 - this.b1;
this.a1 = new int[this.size * 2];
this.a2 = new int[this.size * 2];
this.table = new int[this.b2];
this.aa = new int[this.size];
this.LENS = new int[this.size];
}
void reset() {
for (int i = 0; i < this.size; i++) {
this.LENS[i] = 0;
this.aa[i] = 0;
}
}
void readLengths() {
for (int i = 0; i < this.size; i++) {
this.LENS[i] = this.decompressor.readBits(3);
}
}
void readLengths(int first, int last) throws CorruptCabException {
for(int i = 0;i<20;i++) {
this.root.LENS[i] = (byte) this.decompressor.readBits(4);
}
this.root.buildTable();
for (int i = first; i < last; i++) {
int k = this.root.decodeElement();
int j;
if (k == 17) {
j = this.decompressor.readBits(4) + 4;
if (i + j >= last) {
j = last - i;
}
while (j-- > 0) {
this.LENS[i++] = 0;
}
i--;
}
else if (k == 18) {
j = this.decompressor.readBits(5) + 20;
if (i + j >= last) {
j = last - i;
}
while (j-- > 0) {
this.LENS[i++] = 0;
}
i--;
}
else if (k == 19) {
j = this.decompressor.readBits(1) + 4;
if (i + j >= last) {
j = last - i;
}
k = this.root.decodeElement();
int m = array[this.aa[i] - k + 17];
while (j-- > 0) {
this.LENS[i++] = m;
}
i--;
}
else {
this.LENS[i] = array[this.aa[i] - k + 17];
}
}
}
void buildTable() throws CorruptCabException {
int[] table = this.table;
int[] c3 = this.c3;
int b1 = this.b1;
int i = 1;
do {
this.c1[i] = 0;
i++;
} while (i <= 16);
for (i = 0; i < this.size; i++) {
this.c1[this.LENS[i]]++;
}
c3[1] = 0;
i = 1;
do {
c3[i + 1] = c3[i] + (this.c1[i] << 16 - i);
i++;
} while (i <= 16);
if (c3[17] != 65536) {
if (c3[17] == 0) {
for (i = 0; i < this.b2; i++) {
table[i] = 0;
}
return;
}
throw new CorruptCabException();
}
int i2 = 16 - b1;
for (i = 1; i <= b1; i++) {
c3[i] >>>= i2;
this.c2[i] = 1 << b1 - i;
}
while (i <= 16) {
this.c2[i] = 1 << 16 - i;
i++;
}
i = c3[b1 + 1] >>> i2;
if (i != 65536) {
while (i < this.b2) {
table[i] = 0;
i++;
}
}
int k = this.size;
for (int j = 0; j < this.size; j++) {
int i1 = this.LENS[j];
if (i1 != 0) {
int m = c3[i1] + this.c2[i1];
if (i1 <= b1) {
if (m > this.b2) {
throw new CorruptCabException();
}
for (i = c3[i1]; i < m; i++) {
table[i] = j;
}
c3[i1] = m;
} else {
int n = c3[i1];
c3[i1] = m;
int i6 = n >>> i2;
int i5 = 2;
i = i1 - b1;
n <<= b1;
do {
int i4;
if (i5 == 2) {
i4 = table[i6];
}
else if (i5 == 0) {
i4 = this.a1[i6];
}
else {
i4 = this.a2[i6];
}
if (i4 == 0) {
this.a1[k] = 0;
this.a2[k] = 0;
if (i5 == 2) {
table[i6] = -k;
} else if (i5 == 0) {
this.a1[i6] = -k;
} else {
this.a2[i6] = -k;
}
i4 = -k;
k++;
}
i6 = -i4;
if ((n & 0x8000) == 0) {
i5 = 0;
} else {
i5 = 1;
}
n <<= 1;
i--;
} while (i != 0);
if (i5 == 0) {
this.a1[i6] = j;
} else {
this.a2[i6] = j;
}
}
}
}
}
void read() {
System.arraycopy(this.LENS, 0, this.aa, 0, this.size);
}
int decodeElement() {
int i = this.table[this.decompressor.bitsLeft >>> this.b4 & this.b3];
while (i < 0) {
int j = 1 << this.b4 - 1;
do {
i = -i;
if ((this.decompressor.bitsLeft & j) == 0) {
i = this.a1[i];
} else {
i = this.a2[i];
}
j >>>= 1;
} while (i < 0);
}
this.decompressor.readNumberBits(this.LENS[i]);
return i;
}
}