winscrape/agent-smith/src/dorkbox/cabParser/decompress/lzx/DecompressLzxTree.java

/*
 * 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;
    }
}