/**
   * Restores the last saved state of this object. An IllegalArgumentException is thrown if no state
   * has been saved.
   *
   * @see #save
   */
  public void restore() {
    int maxsbi, minsbi;

    if (!saved) {
      throw new IllegalArgumentException();
    }

    // Invalidate last encoded body buffer
    lbbuf = null;

    // -- Restore tha data

    // Use reference caches to minimize array access overhead
    TagTreeEncoder ttIncl_t_c[][][], ttMaxBP_t_c[][][], ttIncl_t_c_r[][], ttMaxBP_t_c_r[][];
    int lblock_t_c[][][], bak_lblock_t_c[][][], prevtIdxs_t_c_r[][], bak_prevtIdxs_t_c_r[][];

    // Loop on tiles
    for (int t = ttIncl.length - 1; t >= 0; t--) {
      // Loop on components
      for (int c = ttIncl[t].length - 1; c >= 0; c--) {
        // Initialize reference caches
        lblock_t_c = lblock[t][c];
        bak_lblock_t_c = bak_lblock[t][c];
        ttIncl_t_c = ttIncl[t][c];
        ttMaxBP_t_c = ttMaxBP[t][c];
        // Loop on resolution levels
        for (int r = lblock_t_c.length - 1; r >= 0; r--) {
          // Initialize reference caches
          ttIncl_t_c_r = ttIncl_t_c[r];
          ttMaxBP_t_c_r = ttMaxBP_t_c[r];
          prevtIdxs_t_c_r = prevtIdxs[t][c][r];
          bak_prevtIdxs_t_c_r = bak_prevtIdxs[t][c][r];

          // Loop on subbands
          minsbi = (r == 0) ? 0 : 1;
          maxsbi = (r == 0) ? 1 : 4;
          for (int s = minsbi; s < maxsbi; s++) {
            // Restore 'lblock'
            System.arraycopy(bak_lblock_t_c[r][s], 0, lblock_t_c[r][s], 0, lblock_t_c[r][s].length);
            // Restore 'prevtIdxs'
            System.arraycopy(
                bak_prevtIdxs_t_c_r[s], 0, prevtIdxs_t_c_r[s], 0, prevtIdxs_t_c_r[s].length);
          } // End loop on subbands

          // Loop on precincts
          for (int p = ppinfo[t][c][r].length - 1; p >= 0; p--) {
            if (p < ttIncl_t_c_r.length) {
              // Loop on subbands
              for (int s = minsbi; s < maxsbi; s++) {
                ttIncl_t_c_r[p][s].restore();
                ttMaxBP_t_c_r[p][s].restore();
              } // End loop on subbands
            }
          } // End loop on precincts
        } // End loop on resolution levels
      } // End loop on components
    } // End loop on tiles
  }
  /**
   * Encodes a packet and returns the buffer containing the encoded packet header. The code-blocks
   * appear in a 3D array of CBlkRateDistStats, 'cbs'. The first index is the tile index in
   * lexicographical order, the second index is the subband index (as defined in the Subband class),
   * and the third index is the code-block index (whithin the subband tile) in lexicographical order
   * as well. The indexes of the new truncation points for each code-block are specified by the 3D
   * array of int 'tIndx'. The indices of this array are the same as for cbs. The truncation point
   * indices in 'tIndx' are the indices of the elements of the 'truncIdxs' array, of the
   * CBlkRateDistStats class, that give the real truncation points. If a truncation point index is
   * negative it means that the code-block has not been included in any layer yet. If the truncation
   * point is less than or equal to the highest truncation point used in previous layers then the
   * code-block is not included in the packet. Otherwise, if larger, the code-block is included in
   * the packet. The body of the packet can be obtained with the getLastBodyBuf() and
   * getLastBodyLen() methods.
   *
   * <p>Layers must be coded in increasing order, in consecutive manner, for each tile, component
   * and resolution level (e.g., layer 1, then layer 2, etc.). For different tile, component and/or
   * resolution level no particular order must be followed.
   *
   * @param ly The layer index (starts at 1).
   * @param c The component index.
   * @param r The resolution level
   * @param t Index of the current tile
   * @param cbs The 3D array of coded code-blocks.
   * @param tIndx The truncation point indices for each code-block.
   * @param hbuf The header buffer. If null a new BitOutputBuffer is created and returned. This
   *     buffer is reset before anything is written to it.
   * @param bbuf The body buffer. If null a new one is created. If not large enough a new one is
   *     created.
   * @param pIdx The precinct index.
   * @return The buffer containing the packet header.
   */
  public BitOutputBuffer encodePacket(
      int ly,
      int c,
      int r,
      int t,
      CBlkRateDistStats cbs[][],
      int tIndx[][],
      BitOutputBuffer hbuf,
      byte bbuf[],
      int pIdx) {
    int b, i, maxi;
    int ncb;
    int thmax;
    int newtp;
    int cblen;
    int prednbits, nbits, deltabits;
    TagTreeEncoder cur_ttIncl, cur_ttMaxBP; // inclusion and bit-depth tag
    // trees
    int cur_prevtIdxs[]; // last encoded truncation points
    CBlkRateDistStats cur_cbs[];
    int cur_tIndx[]; // truncation points to encode
    int minsb = (r == 0) ? 0 : 1;
    int maxsb = (r == 0) ? 1 : 4;
    Point cbCoord = null;
    SubbandAn root = infoSrc.getAnSubbandTree(t, c);
    SubbandAn sb;
    roiInPkt = false;
    roiLen = 0;
    int mend, nend;

    // Checks if a precinct with such an index exists in this resolution
    // level
    if (pIdx >= ppinfo[t][c][r].length) {
      packetWritable = false;
      return hbuf;
    }
    PrecInfo prec = ppinfo[t][c][r][pIdx];

    // First, we check if packet is empty (i.e precinct 'pIdx' has no
    // code-block in any of the subbands)
    boolean isPrecVoid = true;

    for (int s = minsb; s < maxsb; s++) {
      if (prec.nblk[s] == 0) {
        // The precinct has no code-block in this subband.
        continue;
      } else {
        // The precinct is not empty in at least one subband ->
        // stop
        isPrecVoid = false;
        break;
      }
    }

    if (isPrecVoid) {
      packetWritable = true;

      if (hbuf == null) {
        hbuf = new BitOutputBuffer();
      } else {
        hbuf.reset();
      }
      if (bbuf == null) {
        lbbuf = bbuf = new byte[1];
      }
      hbuf.writeBit(0);
      lblen = 0;

      return hbuf;
    }

    if (hbuf == null) {
      hbuf = new BitOutputBuffer();
    } else {
      hbuf.reset();
    }

    // Invalidate last body buffer
    lbbuf = null;
    lblen = 0;

    // Signal that packet is present
    hbuf.writeBit(1);

    for (int s = minsb; s < maxsb; s++) { // Loop on subbands
      sb = (SubbandAn) root.getSubbandByIdx(r, s);

      // Go directly to next subband if the precinct has no code-block
      // in the current one.
      if (prec.nblk[s] == 0) {
        continue;
      }

      cur_ttIncl = ttIncl[t][c][r][pIdx][s];
      cur_ttMaxBP = ttMaxBP[t][c][r][pIdx][s];
      cur_prevtIdxs = prevtIdxs[t][c][r][s];
      cur_cbs = cbs[s];
      cur_tIndx = tIndx[s];

      // Set tag tree values for code-blocks in this precinct
      mend = (prec.cblk[s] == null) ? 0 : prec.cblk[s].length;
      for (int m = 0; m < mend; m++) {
        nend = (prec.cblk[s][m] == null) ? 0 : prec.cblk[s][m].length;
        for (int n = 0; n < nend; n++) {
          cbCoord = prec.cblk[s][m][n].idx;
          b = cbCoord.x + cbCoord.y * sb.numCb.x;

          if (cur_tIndx[b] > cur_prevtIdxs[b] && cur_prevtIdxs[b] < 0) {
            // First inclusion
            cur_ttIncl.setValue(m, n, ly - 1);
          }
          if (ly == 1) { // First layer, need to set the skip of MSBP
            cur_ttMaxBP.setValue(m, n, cur_cbs[b].skipMSBP);
          }
        }
      }

      // Now encode the information
      for (int m = 0; m < prec.cblk[s].length; m++) { // Vertical code-blocks
        for (int n = 0; n < prec.cblk[s][m].length; n++) { // Horiz. cblks
          cbCoord = prec.cblk[s][m][n].idx;
          b = cbCoord.x + cbCoord.y * sb.numCb.x;

          // 1) Inclusion information
          if (cur_tIndx[b] > cur_prevtIdxs[b]) {
            // Code-block included in this layer
            if (cur_prevtIdxs[b] < 0) { // First inclusion
              // Encode layer info
              cur_ttIncl.encode(m, n, ly, hbuf);

              // 2) Max bitdepth info. Encode value
              thmax = cur_cbs[b].skipMSBP + 1;
              for (i = 1; i <= thmax; i++) {
                cur_ttMaxBP.encode(m, n, i, hbuf);
              }

              // Count body size for packet
              lblen += cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_tIndx[b]]];
            } else { // Already in previous layer
              // Send "1" bit
              hbuf.writeBit(1);
              // Count body size for packet
              lblen +=
                  cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_tIndx[b]]]
                      - cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_prevtIdxs[b]]];
            }

            // 3) Truncation point information
            if (cur_prevtIdxs[b] < 0) {
              newtp = cur_cbs[b].truncIdxs[cur_tIndx[b]];
            } else {
              newtp =
                  cur_cbs[b].truncIdxs[cur_tIndx[b]] - cur_cbs[b].truncIdxs[cur_prevtIdxs[b]] - 1;
            }

            // Mix of switch and if is faster
            switch (newtp) {
              case 0:
                hbuf.writeBit(0); // Send one "0" bit
                break;
              case 1:
                hbuf.writeBits(2, 2); // Send one "1" and one "0"
                break;
              case 2:
              case 3:
              case 4:
                // Send two "1" bits followed by 2 bits
                // representation of newtp-2
                hbuf.writeBits((3 << 2) | (newtp - 2), 4);
                break;
              default:
                if (newtp <= 35) {
                  // Send four "1" bits followed by a five bits
                  // representation of newtp-5
                  hbuf.writeBits((15 << 5) | (newtp - 5), 9);
                } else if (newtp <= 163) {
                  // Send nine "1" bits followed by a seven bits
                  // representation of newtp-36
                  hbuf.writeBits((511 << 7) | (newtp - 36), 16);
                } else {
                  throw new ArithmeticException(
                      "Maximum number " + "of truncation " + "points exceeded");
                }
            }
          } else { // Block not included in this layer
            if (cur_prevtIdxs[b] >= 0) {
              // Already in previous layer. Send "0" bit
              hbuf.writeBit(0);
            } else { // Not in any previous layers
              cur_ttIncl.encode(m, n, ly, hbuf);
            }
            // Go to the next one.
            continue;
          }

          // Code-block length

          // We need to compute the maximum number of bits needed to
          // signal the length of each terminated segment and the
          // final truncation point.
          newtp = 1;
          maxi = cur_cbs[b].truncIdxs[cur_tIndx[b]];
          cblen =
              (cur_prevtIdxs[b] < 0)
                  ? 0
                  : cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_prevtIdxs[b]]];

          // Loop on truncation points
          i = (cur_prevtIdxs[b] < 0) ? 0 : cur_cbs[b].truncIdxs[cur_prevtIdxs[b]] + 1;
          int minbits = 0;
          for (; i < maxi; i++, newtp++) {
            // If terminated truncation point calculate length
            if (cur_cbs[b].isTermPass != null && cur_cbs[b].isTermPass[i]) {

              // Calculate length
              cblen = cur_cbs[b].truncRates[i] - cblen;

              // Calculate number of needed bits
              prednbits = lblock[t][c][r][s][b] + MathUtil.log2(newtp);
              minbits = ((cblen > 0) ? MathUtil.log2(cblen) : 0) + 1;

              // Update Lblock increment if needed
              for (int j = prednbits; j < minbits; j++) {
                lblock[t][c][r][s][b]++;
                hbuf.writeBit(1);
              }
              // Initialize for next length
              newtp = 0;
              cblen = cur_cbs[b].truncRates[i];
            }
          }
          // Last truncation point length always sent

          // Calculate length
          cblen = cur_cbs[b].truncRates[i] - cblen;

          // Calculate number of bits
          prednbits = lblock[t][c][r][s][b] + MathUtil.log2(newtp);
          minbits = ((cblen > 0) ? MathUtil.log2(cblen) : 0) + 1;
          // Update Lblock increment if needed
          for (int j = prednbits; j < minbits; j++) {
            lblock[t][c][r][s][b]++;
            hbuf.writeBit(1);
          }

          // End of comma-code increment
          hbuf.writeBit(0);

          // There can be terminated several segments, send length
          // info for all terminated truncation points in addition
          // to final one
          newtp = 1;
          maxi = cur_cbs[b].truncIdxs[cur_tIndx[b]];
          cblen =
              (cur_prevtIdxs[b] < 0)
                  ? 0
                  : cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_prevtIdxs[b]]];
          // Loop on truncation points and count the groups
          i = (cur_prevtIdxs[b] < 0) ? 0 : cur_cbs[b].truncIdxs[cur_prevtIdxs[b]] + 1;
          for (; i < maxi; i++, newtp++) {
            // If terminated truncation point, send length
            if (cur_cbs[b].isTermPass != null && cur_cbs[b].isTermPass[i]) {

              cblen = cur_cbs[b].truncRates[i] - cblen;
              nbits = MathUtil.log2(newtp) + lblock[t][c][r][s][b];
              hbuf.writeBits(cblen, nbits);

              // Initialize for next length
              newtp = 0;
              cblen = cur_cbs[b].truncRates[i];
            }
          }
          // Last truncation point length is always signalled
          // First calculate number of bits needed to signal
          // Calculate length
          cblen = cur_cbs[b].truncRates[i] - cblen;
          nbits = MathUtil.log2(newtp) + lblock[t][c][r][s][b];
          hbuf.writeBits(cblen, nbits);
        } // End loop on horizontal code-blocks
      } // End loop on vertical code-blocks
    } // End loop on subband

    // -> Copy the data to the body buffer

    // Ensure size for body data
    if (bbuf == null || bbuf.length < lblen) {
      bbuf = new byte[lblen];
    }
    lbbuf = bbuf;
    lblen = 0;

    for (int s = minsb; s < maxsb; s++) { // Loop on subbands
      sb = (SubbandAn) root.getSubbandByIdx(r, s);

      cur_prevtIdxs = prevtIdxs[t][c][r][s];
      cur_cbs = cbs[s];
      cur_tIndx = tIndx[s];
      ncb = cur_prevtIdxs.length;

      mend = (prec.cblk[s] == null) ? 0 : prec.cblk[s].length;
      for (int m = 0; m < mend; m++) { // Vertical code-blocks
        nend = (prec.cblk[s][m] == null) ? 0 : prec.cblk[s][m].length;
        for (int n = 0; n < nend; n++) { // Horiz. cblks
          cbCoord = prec.cblk[s][m][n].idx;
          b = cbCoord.x + cbCoord.y * sb.numCb.x;

          if (cur_tIndx[b] > cur_prevtIdxs[b]) {

            // Block included in this precinct -> Copy data to
            // body buffer and get code-size
            if (cur_prevtIdxs[b] < 0) {
              cblen = cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_tIndx[b]]];
              System.arraycopy(cur_cbs[b].data, 0, lbbuf, lblen, cblen);
            } else {
              cblen =
                  cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_tIndx[b]]]
                      - cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_prevtIdxs[b]]];
              System.arraycopy(
                  cur_cbs[b].data,
                  cur_cbs[b].truncRates[cur_cbs[b].truncIdxs[cur_prevtIdxs[b]]],
                  lbbuf,
                  lblen,
                  cblen);
            }
            lblen += cblen;

            // Verifies if this code-block contains new ROI
            // information
            if (cur_cbs[b].nROIcoeff != 0
                && (cur_prevtIdxs[b] == -1
                    || cur_cbs[b].truncIdxs[cur_prevtIdxs[b]] <= cur_cbs[b].nROIcp - 1)) {
              roiInPkt = true;
              roiLen = lblen;
            }

            // Update truncation point
            cur_prevtIdxs[b] = cur_tIndx[b];
          }
        } // End loop on horizontal code-blocks
      } // End loop on vertical code-blocks
    } // End loop on subbands

    packetWritable = true;

    // Must never happen
    if (hbuf.getLength() == 0) {
      throw new Error("You have found a bug in PktEncoder, method:" + " encodePacket");
    }

    return hbuf;
  }
  /**
   * Saves the current state of this object. The last saved state can be restored with the restore()
   * method.
   *
   * @see #restore
   */
  public void save() {
    int maxsbi, minsbi;

    // Have we done any save yet?
    if (bak_lblock == null) {
      // Allocate backup buffers
      bak_lblock = new int[ttIncl.length][][][][];
      bak_prevtIdxs = new int[ttIncl.length][][][][];
      for (int t = ttIncl.length - 1; t >= 0; t--) {
        bak_lblock[t] = new int[ttIncl[t].length][][][];
        bak_prevtIdxs[t] = new int[ttIncl[t].length][][][];
        for (int c = ttIncl[t].length - 1; c >= 0; c--) {
          bak_lblock[t][c] = new int[lblock[t][c].length][][];
          bak_prevtIdxs[t][c] = new int[ttIncl[t][c].length][][];
          for (int r = lblock[t][c].length - 1; r >= 0; r--) {
            bak_lblock[t][c][r] = new int[lblock[t][c][r].length][];
            bak_prevtIdxs[t][c][r] = new int[prevtIdxs[t][c][r].length][];
            minsbi = (r == 0) ? 0 : 1;
            maxsbi = (r == 0) ? 1 : 4;
            for (int s = minsbi; s < maxsbi; s++) {
              bak_lblock[t][c][r][s] = new int[lblock[t][c][r][s].length];
              bak_prevtIdxs[t][c][r][s] = new int[prevtIdxs[t][c][r][s].length];
            }
          }
        }
      }
    }

    // -- Save the data

    // Use reference caches to minimize array access overhead
    TagTreeEncoder ttIncl_t_c[][][], ttMaxBP_t_c[][][], ttIncl_t_c_r[][], ttMaxBP_t_c_r[][];
    int lblock_t_c[][][], bak_lblock_t_c[][][], prevtIdxs_t_c_r[][], bak_prevtIdxs_t_c_r[][];

    // Loop on tiles
    for (int t = ttIncl.length - 1; t >= 0; t--) {
      // Loop on components
      for (int c = ttIncl[t].length - 1; c >= 0; c--) {
        // Initialize reference caches
        lblock_t_c = lblock[t][c];
        bak_lblock_t_c = bak_lblock[t][c];
        ttIncl_t_c = ttIncl[t][c];
        ttMaxBP_t_c = ttMaxBP[t][c];
        // Loop on resolution levels
        for (int r = lblock_t_c.length - 1; r >= 0; r--) {
          // Initialize reference caches
          ttIncl_t_c_r = ttIncl_t_c[r];
          ttMaxBP_t_c_r = ttMaxBP_t_c[r];
          prevtIdxs_t_c_r = prevtIdxs[t][c][r];
          bak_prevtIdxs_t_c_r = bak_prevtIdxs[t][c][r];

          // Loop on subbands
          minsbi = (r == 0) ? 0 : 1;
          maxsbi = (r == 0) ? 1 : 4;
          for (int s = minsbi; s < maxsbi; s++) {
            // Save 'lblock'
            System.arraycopy(lblock_t_c[r][s], 0, bak_lblock_t_c[r][s], 0, lblock_t_c[r][s].length);
            // Save 'prevtIdxs'
            System.arraycopy(
                prevtIdxs_t_c_r[s], 0, bak_prevtIdxs_t_c_r[s], 0, prevtIdxs_t_c_r[s].length);
          } // End loop on subbands

          // Loop on precincts
          for (int p = ppinfo[t][c][r].length - 1; p >= 0; p--) {
            if (p < ttIncl_t_c_r.length) {
              // Loop on subbands
              for (int s = minsbi; s < maxsbi; s++) {
                ttIncl_t_c_r[p][s].save();
                ttMaxBP_t_c_r[p][s].save();
              } // End loop on subbands
            }
          } // End loop on precincts
        } // End loop on resolutions
      } // End loop on components
    } // End loop on tiles

    // Set the saved state
    saved = true;
  }