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The Bouncy Castle Java APIs for the OpenPGP Protocol. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified and used appropriately.

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 *
 */

/*
 * This package is based on the work done by Keiron Liddle, Aftex Software
 *  to whom the Ant project is very grateful for his
 * great code.
 */
package org.bouncycastle.apache.bzip2;

import java.io.InputStream;
import java.io.IOException;

/**
 * An input stream that decompresses from the BZip2 format (with the file
 * header chars) to be read as any other stream.
 *
 * @author Keiron Liddle
 *
 * NB: note this class has been modified to read the leading BZ from the
 * start of the BZIP2 stream to make it compatible with other PGP programs.
 */
public class CBZip2InputStream extends InputStream implements BZip2Constants {
    private static void cadvise() {
        System.out.println("CRC Error");
        //throw new CCoruptionError();
    }

//    private static void badBGLengths() {
//        cadvise();
//    }
//
//    private static void bitStreamEOF() {
//        cadvise();
//    }

    private static void compressedStreamEOF() {
        cadvise();
    }

    private void makeMaps() {
        int i;
        nInUse = 0;
        for (i = 0; i < 256; i++) {
            if (inUse[i]) {
                seqToUnseq[nInUse] = (char) i;
                unseqToSeq[i] = (char) nInUse;
                nInUse++;
            }
        }
    }

    /*
      index of the last char in the block, so
      the block size == last + 1.
    */
    private int  last;

    /*
      index in zptr[] of original string after sorting.
    */
    private int  origPtr;

    /*
      always: in the range 0 .. 9.
      The current block size is 100000 * this number.
    */
    private int blockSize100k;

    private boolean blockRandomised;

    private int bsBuff;
    private int bsLive;
    private CRC mCrc = new CRC();

    private boolean[] inUse = new boolean[256];
    private int nInUse;

    private char[] seqToUnseq = new char[256];
    private char[] unseqToSeq = new char[256];

    private char[] selector = new char[MAX_SELECTORS];
    private char[] selectorMtf = new char[MAX_SELECTORS];

    private int[] tt;
    private char[] ll8;

    /*
      freq table collected to save a pass over the data
      during decompression.
    */
    private int[] unzftab = new int[256];

    private int[][] limit = new int[N_GROUPS][MAX_ALPHA_SIZE];
    private int[][] base = new int[N_GROUPS][MAX_ALPHA_SIZE];
    private int[][] perm = new int[N_GROUPS][MAX_ALPHA_SIZE];
    private int[] minLens = new int[N_GROUPS];

    private InputStream bsStream;

    private boolean streamEnd = false;

    private int currentChar = -1;

    private static final int START_BLOCK_STATE = 1;
    private static final int RAND_PART_A_STATE = 2;
    private static final int RAND_PART_B_STATE = 3;
    private static final int RAND_PART_C_STATE = 4;
    private static final int NO_RAND_PART_A_STATE = 5;
    private static final int NO_RAND_PART_B_STATE = 6;
    private static final int NO_RAND_PART_C_STATE = 7;

    private int currentState = START_BLOCK_STATE;

    private int storedBlockCRC, storedCombinedCRC;
    private int computedBlockCRC, computedCombinedCRC;

    int i2, count, chPrev, ch2;
    int i, tPos;
    int rNToGo = 0;
    int rTPos  = 0;
    int j2;
    char z;

    public CBZip2InputStream(InputStream zStream)
        throws IOException
    {
        ll8 = null;
        tt = null;
        bsSetStream(zStream);
        initialize();
        initBlock();
        setupBlock();
    }

    public int read() {
        if (streamEnd) {
            return -1;
        } else {
            int retChar = currentChar;
            switch(currentState) {
            case START_BLOCK_STATE:
                break;
            case RAND_PART_A_STATE:
                break;
            case RAND_PART_B_STATE:
                setupRandPartB();
                break;
            case RAND_PART_C_STATE:
                setupRandPartC();
                break;
            case NO_RAND_PART_A_STATE:
                break;
            case NO_RAND_PART_B_STATE:
                setupNoRandPartB();
                break;
            case NO_RAND_PART_C_STATE:
                setupNoRandPartC();
                break;
            default:
                break;
            }
            return retChar;
        }
    }

    private void initialize() throws IOException {
        char magic3, magic4;
        magic3 = bsGetUChar();
        magic4 = bsGetUChar();
        if (magic3 != 'B' && magic4 != 'Z')
        {
            throw new IOException("Not a BZIP2 marked stream");
        }
        magic3 = bsGetUChar();
        magic4 = bsGetUChar();
        if (magic3 != 'h' || magic4 < '1' || magic4 > '9') {
            bsFinishedWithStream();
            streamEnd = true;
            return;
        }

        setDecompressStructureSizes(magic4 - '0');
        computedCombinedCRC = 0;
    }

    private void initBlock() {
        char magic1, magic2, magic3, magic4;
        char magic5, magic6;
        magic1 = bsGetUChar();
        magic2 = bsGetUChar();
        magic3 = bsGetUChar();
        magic4 = bsGetUChar();
        magic5 = bsGetUChar();
        magic6 = bsGetUChar();
        if (magic1 == 0x17 && magic2 == 0x72 && magic3 == 0x45
            && magic4 == 0x38 && magic5 == 0x50 && magic6 == 0x90) {
            complete();
            return;
        }

        if (magic1 != 0x31 || magic2 != 0x41 || magic3 != 0x59
            || magic4 != 0x26 || magic5 != 0x53 || magic6 != 0x59) {
            badBlockHeader();
            streamEnd = true;
            return;
        }

        storedBlockCRC = bsGetInt32();

        if (bsR(1) == 1) {
            blockRandomised = true;
        } else {
            blockRandomised = false;
        }

        //        currBlockNo++;
        getAndMoveToFrontDecode();

        mCrc.initialiseCRC();
        currentState = START_BLOCK_STATE;
    }

    private void endBlock() {
        computedBlockCRC = mCrc.getFinalCRC();
        /* A bad CRC is considered a fatal error. */
        if (storedBlockCRC != computedBlockCRC) {
            crcError();
        }

        computedCombinedCRC = (computedCombinedCRC << 1)
            | (computedCombinedCRC >>> 31);
        computedCombinedCRC ^= computedBlockCRC;
    }

    private void complete() {
        storedCombinedCRC = bsGetInt32();
        if (storedCombinedCRC != computedCombinedCRC) {
            crcError();
        }

        bsFinishedWithStream();
        streamEnd = true;
    }

    private static void blockOverrun() {
        cadvise();
    }

    private static void badBlockHeader() {
        cadvise();
    }

    private static void crcError() {
        cadvise();
    }

    private void bsFinishedWithStream() {
        try {
            if (this.bsStream != null) {
                if (this.bsStream != System.in) {
                    this.bsStream.close();
                    this.bsStream = null;
                }
            }
        } catch (IOException ioe) {
            //ignore
        }
    }

    private void bsSetStream(InputStream f) {
        bsStream = f;
        bsLive = 0;
        bsBuff = 0;
    }

    private int bsR(int n) {
        int v;
        while (bsLive < n) {
            int zzi;
            char thech = 0;
            try {
                thech = (char) bsStream.read();
            } catch (IOException e) {
                compressedStreamEOF();
            }
            if (thech == -1) {
                compressedStreamEOF();
            }
            zzi = thech;
            bsBuff = (bsBuff << 8) | (zzi & 0xff);
            bsLive += 8;
        }

        v = (bsBuff >> (bsLive - n)) & ((1 << n) - 1);
        bsLive -= n;
        return v;
    }

    private char bsGetUChar() {
        return (char) bsR(8);
    }

    private int bsGetint() {
        int u = 0;
        u = (u << 8) | bsR(8);
        u = (u << 8) | bsR(8);
        u = (u << 8) | bsR(8);
        u = (u << 8) | bsR(8);
        return u;
    }

    private int bsGetIntVS(int numBits) {
        return (int) bsR(numBits);
    }

    private int bsGetInt32() {
        return (int) bsGetint();
    }

    private void hbCreateDecodeTables(int[] limit, int[] base,
                                      int[] perm, char[] length,
                                      int minLen, int maxLen, int alphaSize) {
        int pp, i, j, vec;

        pp = 0;
        for (i = minLen; i <= maxLen; i++) {
            for (j = 0; j < alphaSize; j++) {
                if (length[j] == i) {
                    perm[pp] = j;
                    pp++;
                }
            }
        }

        for (i = 0; i < MAX_CODE_LEN; i++) {
            base[i] = 0;
        }
        for (i = 0; i < alphaSize; i++) {
            base[length[i] + 1]++;
        }

        for (i = 1; i < MAX_CODE_LEN; i++) {
            base[i] += base[i - 1];
        }

        for (i = 0; i < MAX_CODE_LEN; i++) {
            limit[i] = 0;
        }
        vec = 0;

        for (i = minLen; i <= maxLen; i++) {
            vec += (base[i + 1] - base[i]);
            limit[i] = vec - 1;
            vec <<= 1;
        }
        for (i = minLen + 1; i <= maxLen; i++) {
            base[i] = ((limit[i - 1] + 1) << 1) - base[i];
        }
    }

    private void recvDecodingTables() {
        char len[][] = new char[N_GROUPS][MAX_ALPHA_SIZE];
        int i, j, t, nGroups, nSelectors, alphaSize;
        int minLen, maxLen;
        boolean[] inUse16 = new boolean[16];

        /* Receive the mapping table */
        for (i = 0; i < 16; i++) {
            if (bsR(1) == 1) {
                inUse16[i] = true;
            } else {
                inUse16[i] = false;
            }
        }

        for (i = 0; i < 256; i++) {
            inUse[i] = false;
        }

        for (i = 0; i < 16; i++) {
            if (inUse16[i]) {
                for (j = 0; j < 16; j++) {
                    if (bsR(1) == 1) {
                        inUse[i * 16 + j] = true;
                    }
                }
            }
        }

        makeMaps();
        alphaSize = nInUse + 2;

        /* Now the selectors */
        nGroups = bsR(3);
        nSelectors = bsR(15);
        for (i = 0; i < nSelectors; i++) {
            j = 0;
            while (bsR(1) == 1) {
                j++;
            }
            selectorMtf[i] = (char) j;
        }

        /* Undo the MTF values for the selectors. */
        {
            char[] pos = new char[N_GROUPS];
            char tmp, v;
            for (v = 0; v < nGroups; v++) {
                pos[v] = v;
            }

            for (i = 0; i < nSelectors; i++) {
                v = selectorMtf[i];
                tmp = pos[v];
                while (v > 0) {
                    pos[v] = pos[v - 1];
                    v--;
                }
                pos[0] = tmp;
                selector[i] = tmp;
            }
        }

        /* Now the coding tables */
        for (t = 0; t < nGroups; t++) {
            int curr = bsR(5);
            for (i = 0; i < alphaSize; i++) {
                while (bsR(1) == 1) {
                    if (bsR(1) == 0) {
                        curr++;
                    } else {
                        curr--;
                    }
                }
                len[t][i] = (char) curr;
            }
        }

        /* Create the Huffman decoding tables */
        for (t = 0; t < nGroups; t++) {
            minLen = 32;
            maxLen = 0;
            for (i = 0; i < alphaSize; i++) {
                if (len[t][i] > maxLen) {
                    maxLen = len[t][i];
                }
                if (len[t][i] < minLen) {
                    minLen = len[t][i];
                }
            }
            hbCreateDecodeTables(limit[t], base[t], perm[t], len[t], minLen,
                                 maxLen, alphaSize);
            minLens[t] = minLen;
        }
    }

    private void getAndMoveToFrontDecode() {
        char[] yy = new char[256];
        int i, j, nextSym, limitLast;
        int EOB, groupNo, groupPos;

        limitLast = baseBlockSize * blockSize100k;
        origPtr = bsGetIntVS(24);

        recvDecodingTables();
        EOB = nInUse + 1;
        groupNo = -1;
        groupPos = 0;

        /*
          Setting up the unzftab entries here is not strictly
          necessary, but it does save having to do it later
          in a separate pass, and so saves a block's worth of
          cache misses.
        */
        for (i = 0; i <= 255; i++) {
            unzftab[i] = 0;
        }

        for (i = 0; i <= 255; i++) {
            yy[i] = (char) i;
        }

        last = -1;

        {
            int zt, zn, zvec, zj;
            if (groupPos == 0) {
                groupNo++;
                groupPos = G_SIZE;
            }
            groupPos--;
            zt = selector[groupNo];
            zn = minLens[zt];
            zvec = bsR(zn);
            while (zvec > limit[zt][zn]) {
                zn++;
                {
                    {
                        while (bsLive < 1) {
                            int zzi;
                            char thech = 0;
                            try {
                                thech = (char) bsStream.read();
                            } catch (IOException e) {
                                compressedStreamEOF();
                            }
                            if (thech == -1) {
                                compressedStreamEOF();
                            }
                            zzi = thech;
                            bsBuff = (bsBuff << 8) | (zzi & 0xff);
                            bsLive += 8;
                        }
                    }
                    zj = (bsBuff >> (bsLive - 1)) & 1;
                    bsLive--;
                }
                zvec = (zvec << 1) | zj;
            }
            nextSym = perm[zt][zvec - base[zt][zn]];
        }

        while (true) {

            if (nextSym == EOB) {
                break;
            }

            if (nextSym == RUNA || nextSym == RUNB) {
                char ch;
                int s = -1;
                int N = 1;
                do {
                    if (nextSym == RUNA) {
                        s = s + (0 + 1) * N;
                    } else if (nextSym == RUNB) {
                        s = s + (1 + 1) * N;
                           }
                    N = N * 2;
                    {
                        int zt, zn, zvec, zj;
                        if (groupPos == 0) {
                            groupNo++;
                            groupPos = G_SIZE;
                        }
                        groupPos--;
                        zt = selector[groupNo];
                        zn = minLens[zt];
                        zvec = bsR(zn);
                        while (zvec > limit[zt][zn]) {
                            zn++;
                            {
                                {
                                    while (bsLive < 1) {
                                        int zzi;
                                        char thech = 0;
                                        try {
                                            thech = (char) bsStream.read();
                                        } catch (IOException e) {
                                            compressedStreamEOF();
                                        }
                                        if (thech == -1) {
                                            compressedStreamEOF();
                                        }
                                        zzi = thech;
                                        bsBuff = (bsBuff << 8) | (zzi & 0xff);
                                        bsLive += 8;
                                    }
                                }
                                zj = (bsBuff >> (bsLive - 1)) & 1;
                                bsLive--;
                            }
                            zvec = (zvec << 1) | zj;
                        }
                        nextSym = perm[zt][zvec - base[zt][zn]];
                    }
                } while (nextSym == RUNA || nextSym == RUNB);

                s++;
                ch = seqToUnseq[yy[0]];
                unzftab[ch] += s;

                while (s > 0) {
                    last++;
                    ll8[last] = ch;
                    s--;
                }

                if (last >= limitLast) {
                    blockOverrun();
                }
                continue;
            } else {
                char tmp;
                last++;
                if (last >= limitLast) {
                    blockOverrun();
                }

                tmp = yy[nextSym - 1];
                unzftab[seqToUnseq[tmp]]++;
                ll8[last] = seqToUnseq[tmp];

                /*
                  This loop is hammered during decompression,
                  hence the unrolling.

                  for (j = nextSym-1; j > 0; j--) yy[j] = yy[j-1];
                */

                j = nextSym - 1;
                for (; j > 3; j -= 4) {
                    yy[j]     = yy[j - 1];
                    yy[j - 1] = yy[j - 2];
                    yy[j - 2] = yy[j - 3];
                    yy[j - 3] = yy[j - 4];
                }
                for (; j > 0; j--) {
                    yy[j] = yy[j - 1];
                }

                yy[0] = tmp;
                {
                    int zt, zn, zvec, zj;
                    if (groupPos == 0) {
                        groupNo++;
                        groupPos = G_SIZE;
                    }
                    groupPos--;
                    zt = selector[groupNo];
                    zn = minLens[zt];
                    zvec = bsR(zn);
                    while (zvec > limit[zt][zn]) {
                        zn++;
                        {
                            {
                                while (bsLive < 1) {
                                    int zzi;
                                    char thech = 0;
                                    try {
                                        thech = (char) bsStream.read();
                                    } catch (IOException e) {
                                        compressedStreamEOF();
                                    }
                                    zzi = thech;
                                    bsBuff = (bsBuff << 8) | (zzi & 0xff);
                                    bsLive += 8;
                                }
                            }
                            zj = (bsBuff >> (bsLive - 1)) & 1;
                            bsLive--;
                        }
                        zvec = (zvec << 1) | zj;
                    }
                    nextSym = perm[zt][zvec - base[zt][zn]];
                }
                continue;
            }
        }
    }

    private void setupBlock() {
        int[] cftab = new int[257];
        char ch;

        cftab[0] = 0;
        for (i = 1; i <= 256; i++) {
            cftab[i] = unzftab[i - 1];
        }
        for (i = 1; i <= 256; i++) {
            cftab[i] += cftab[i - 1];
        }

        for (i = 0; i <= last; i++) {
            ch = (char) ll8[i];
            tt[cftab[ch]] = i;
            cftab[ch]++;
        }
        cftab = null;

        tPos = tt[origPtr];

        count = 0;
        i2 = 0;
        ch2 = 256;   /* not a char and not EOF */

        if (blockRandomised) {
            rNToGo = 0;
            rTPos = 0;
            setupRandPartA();
        } else {
            setupNoRandPartA();
        }
    }

    private void setupRandPartA() {
        if (i2 <= last) {
            chPrev = ch2;
            ch2 = ll8[tPos];
            tPos = tt[tPos];
            if (rNToGo == 0) {
                rNToGo = rNums[rTPos];
                rTPos++;
                if (rTPos == 512) {
                    rTPos = 0;
                }
            }
            rNToGo--;
            ch2 ^= (int) ((rNToGo == 1) ? 1 : 0);
            i2++;

            currentChar = ch2;
            currentState = RAND_PART_B_STATE;
            mCrc.updateCRC(ch2);
        } else {
            endBlock();
            initBlock();
            setupBlock();
        }
    }

    private void setupNoRandPartA() {
        if (i2 <= last) {
            chPrev = ch2;
            ch2 = ll8[tPos];
            tPos = tt[tPos];
            i2++;

            currentChar = ch2;
            currentState = NO_RAND_PART_B_STATE;
            mCrc.updateCRC(ch2);
        } else {
            endBlock();
            initBlock();
            setupBlock();
        }
    }

    private void setupRandPartB() {
        if (ch2 != chPrev) {
            currentState = RAND_PART_A_STATE;
            count = 1;
            setupRandPartA();
        } else {
            count++;
            if (count >= 4) {
                z = ll8[tPos];
                tPos = tt[tPos];
                if (rNToGo == 0) {
                    rNToGo = rNums[rTPos];
                    rTPos++;
                    if (rTPos == 512) {
                        rTPos = 0;
                    }
                }
                rNToGo--;
                z ^= ((rNToGo == 1) ? 1 : 0);
                j2 = 0;
                currentState = RAND_PART_C_STATE;
                setupRandPartC();
            } else {
                currentState = RAND_PART_A_STATE;
                setupRandPartA();
            }
        }
    }

    private void setupRandPartC() {
        if (j2 < (int) z) {
            currentChar = ch2;
            mCrc.updateCRC(ch2);
            j2++;
        } else {
            currentState = RAND_PART_A_STATE;
            i2++;
            count = 0;
            setupRandPartA();
        }
    }

    private void setupNoRandPartB() {
        if (ch2 != chPrev) {
            currentState = NO_RAND_PART_A_STATE;
            count = 1;
            setupNoRandPartA();
        } else {
            count++;
            if (count >= 4) {
                z = ll8[tPos];
                tPos = tt[tPos];
                currentState = NO_RAND_PART_C_STATE;
                j2 = 0;
                setupNoRandPartC();
            } else {
                currentState = NO_RAND_PART_A_STATE;
                setupNoRandPartA();
            }
        }
    }

    private void setupNoRandPartC() {
        if (j2 < (int) z) {
            currentChar = ch2;
            mCrc.updateCRC(ch2);
            j2++;
        } else {
            currentState = NO_RAND_PART_A_STATE;
            i2++;
            count = 0;
            setupNoRandPartA();
        }
    }

    private void setDecompressStructureSizes(int newSize100k) {
        if (!(0 <= newSize100k && newSize100k <= 9 && 0 <= blockSize100k
               && blockSize100k <= 9)) {
            // throw new IOException("Invalid block size");
        }

        blockSize100k = newSize100k;

        if (newSize100k == 0) {
            return;
        }

        int n = baseBlockSize * newSize100k;
        ll8 = new char[n];
        tt = new int[n];
    }
}





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