/*
 * Copyright (c) 2011 ymnk, JCraft,Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions
 * and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided with
 * the distribution.
 *
 * 3. The names of the authors may not be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL JCRAFT, INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * This program is based on zlib-1.1.3, so all credit should go authors Jean-loup
 * Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu) and contributors of zlib.
 */

package com.jcraft.jsch.jzlib;

final class InfBlocks {
  private static final int MANY = 1440;

  // And'ing with mask[n] masks the lower n bits
  private static final int[] inflate_mask = {0x00000000, 0x00000001, 0x00000003, 0x00000007,
      0x0000000f, 0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 0x000001ff, 0x000003ff,
      0x000007ff, 0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff};

  // Table for deflate from PKZIP's appnote.txt.
  static final int[] border = { // Order of the bit length code lengths
      16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};

  private static final int Z_OK = 0;
  private static final int Z_STREAM_END = 1;
  private static final int Z_NEED_DICT = 2;
  private static final int Z_ERRNO = -1;
  private static final int Z_STREAM_ERROR = -2;
  private static final int Z_DATA_ERROR = -3;
  private static final int Z_MEM_ERROR = -4;
  private static final int Z_BUF_ERROR = -5;
  private static final int Z_VERSION_ERROR = -6;

  private static final int TYPE = 0; // get type bits (3, including end bit)
  private static final int LENS = 1; // get lengths for stored
  private static final int STORED = 2; // processing stored block
  private static final int TABLE = 3; // get table lengths
  private static final int BTREE = 4; // get bit lengths tree for a dynamic block
  private static final int DTREE = 5; // get length, distance trees for a dynamic block
  private static final int CODES = 6; // processing fixed or dynamic block
  private static final int DRY = 7; // output remaining window bytes
  private static final int DONE = 8; // finished last block, done
  private static final int BAD = 9; // ot a data error--stuck here

  int mode; // current inflate_block mode

  int left; // if STORED, bytes left to copy

  int table; // table lengths (14 bits)
  int index; // index into blens (or border)
  int[] blens; // bit lengths of codes
  int[] bb = new int[1]; // bit length tree depth
  int[] tb = new int[1]; // bit length decoding tree

  int[] bl = new int[1];
  int[] bd = new int[1];

  int[][] tl = new int[1][];
  int[][] td = new int[1][];
  int[] tli = new int[1]; // tl_index
  int[] tdi = new int[1]; // td_index

  private final InfCodes codes; // if CODES, current state

  int last; // true if this block is the last block

  // mode independent information
  int bitk; // bits in bit buffer
  int bitb; // bit buffer
  int[] hufts; // single malloc for tree space
  byte[] window; // sliding window
  int end; // one byte after sliding window
  int read; // window read pointer
  int write; // window write pointer
  private boolean check;

  private final InfTree inftree = new InfTree();

  private final ZStream z;

  InfBlocks(ZStream z, int w) {
    this.z = z;
    this.codes = new InfCodes(this.z, this);
    hufts = new int[MANY * 3];
    window = new byte[w];
    end = w;
    this.check = (z.istate.wrap == 0) ? false : true;
    mode = TYPE;
    reset();
  }

  void reset() {
    if (mode == BTREE || mode == DTREE) {
    }
    if (mode == CODES) {
      codes.free(z);
    }
    mode = TYPE;
    bitk = 0;
    bitb = 0;
    read = write = 0;
    if (check) {
      z.adler.reset();
    }
  }

  @SuppressWarnings("fallthrough")
  int proc(int r) {
    int t; // temporary storage
    int b; // bit buffer
    int k; // bits in bit buffer
    int p; // input data pointer
    int n; // bytes available there
    int q; // output window write pointer
    int m; // bytes to end of window or read pointer

    // copy input/output information to locals (UPDATE macro restores)
    {
      p = z.next_in_index;
      n = z.avail_in;
      b = bitb;
      k = bitk;
    }
    {
      q = write;
      m = (q < read ? read - q - 1 : end - q);
    }

    // process input based on current state
    while (true) {
      switch (mode) {
        case TYPE:
          while (k < (3)) {
            if (n != 0) {
              r = Z_OK;
            } else {
              bitb = b;
              bitk = k;
              z.avail_in = n;
              z.total_in += p - z.next_in_index;
              z.next_in_index = p;
              write = q;
              return inflate_flush(r);
            }
            n--;
            b |= (z.next_in[p++] & 0xff) << k;
            k += 8;
          }
          t = b & 7;
          last = t & 1;

          switch (t >>> 1) {
            case 0: // stored
            {
              b >>>= (3);
              k -= (3);
            }
              t = k & 7; // go to byte boundary

            {
              b >>>= (t);
              k -= (t);
            }
              mode = LENS; // get length of stored block
              break;
            case 1: // fixed
              InfTree.inflate_trees_fixed(bl, bd, tl, td, z);
              codes.init(bl[0], bd[0], tl[0], 0, td[0], 0);

            {
              b >>>= (3);
              k -= (3);
            }

              mode = CODES;
              break;
            case 2: // dynamic
            {
              b >>>= (3);
              k -= (3);
            }

              mode = TABLE;
              break;
            case 3: // illegal
            {
              b >>>= (3);
              k -= (3);
            }
              mode = BAD;
              z.msg = "invalid block type";
              r = Z_DATA_ERROR;

              bitb = b;
              bitk = k;
              z.avail_in = n;
              z.total_in += p - z.next_in_index;
              z.next_in_index = p;
              write = q;
              return inflate_flush(r);
          }
          break;
        case LENS:
          while (k < (32)) {
            if (n != 0) {
              r = Z_OK;
            } else {
              bitb = b;
              bitk = k;
              z.avail_in = n;
              z.total_in += p - z.next_in_index;
              z.next_in_index = p;
              write = q;
              return inflate_flush(r);
            }
            n--;
            b |= (z.next_in[p++] & 0xff) << k;
            k += 8;
          }

          if ((((~b) >>> 16) & 0xffff) != (b & 0xffff)) {
            mode = BAD;
            z.msg = "invalid stored block lengths";
            r = Z_DATA_ERROR;

            bitb = b;
            bitk = k;
            z.avail_in = n;
            z.total_in += p - z.next_in_index;
            z.next_in_index = p;
            write = q;
            return inflate_flush(r);
          }
          left = (b & 0xffff);
          b = k = 0; // dump bits
          mode = left != 0 ? STORED : (last != 0 ? DRY : TYPE);
          break;
        case STORED:
          if (n == 0) {
            bitb = b;
            bitk = k;
            z.avail_in = n;
            z.total_in += p - z.next_in_index;
            z.next_in_index = p;
            write = q;
            return inflate_flush(r);
          }

          if (m == 0) {
            if (q == end && read != 0) {
              q = 0;
              m = (q < read ? read - q - 1 : end - q);
            }
            if (m == 0) {
              write = q;
              r = inflate_flush(r);
              q = write;
              m = (q < read ? read - q - 1 : end - q);
              if (q == end && read != 0) {
                q = 0;
                m = (q < read ? read - q - 1 : end - q);
              }
              if (m == 0) {
                bitb = b;
                bitk = k;
                z.avail_in = n;
                z.total_in += p - z.next_in_index;
                z.next_in_index = p;
                write = q;
                return inflate_flush(r);
              }
            }
          }
          r = Z_OK;

          t = left;
          if (t > n)
            t = n;
          if (t > m)
            t = m;
          System.arraycopy(z.next_in, p, window, q, t);
          p += t;
          n -= t;
          q += t;
          m -= t;
          if ((left -= t) != 0)
            break;
          mode = last != 0 ? DRY : TYPE;
          break;
        case TABLE:
          while (k < (14)) {
            if (n != 0) {
              r = Z_OK;
            } else {
              bitb = b;
              bitk = k;
              z.avail_in = n;
              z.total_in += p - z.next_in_index;
              z.next_in_index = p;
              write = q;
              return inflate_flush(r);
            }
            n--;
            b |= (z.next_in[p++] & 0xff) << k;
            k += 8;
          }

          table = t = (b & 0x3fff);
          if ((t & 0x1f) > 29 || ((t >> 5) & 0x1f) > 29) {
            mode = BAD;
            z.msg = "too many length or distance symbols";
            r = Z_DATA_ERROR;

            bitb = b;
            bitk = k;
            z.avail_in = n;
            z.total_in += p - z.next_in_index;
            z.next_in_index = p;
            write = q;
            return inflate_flush(r);
          }
          t = 258 + (t & 0x1f) + ((t >> 5) & 0x1f);
          if (blens == null || blens.length < t) {
            blens = new int[t];
          } else {
            for (int i = 0; i < t; i++) {
              blens[i] = 0;
            }
          }

        {
          b >>>= (14);
          k -= (14);
        }

          index = 0;
          mode = BTREE;
        case BTREE:
          while (index < 4 + (table >>> 10)) {
            while (k < (3)) {
              if (n != 0) {
                r = Z_OK;
              } else {
                bitb = b;
                bitk = k;
                z.avail_in = n;
                z.total_in += p - z.next_in_index;
                z.next_in_index = p;
                write = q;
                return inflate_flush(r);
              }
              n--;
              b |= (z.next_in[p++] & 0xff) << k;
              k += 8;
            }

            blens[border[index++]] = b & 7;

            {
              b >>>= (3);
              k -= (3);
            }
          }

          while (index < 19) {
            blens[border[index++]] = 0;
          }

          bb[0] = 7;
          t = inftree.inflate_trees_bits(blens, bb, tb, hufts, z);
          if (t != Z_OK) {
            r = t;
            if (r == Z_DATA_ERROR) {
              blens = null;
              mode = BAD;
            }

            bitb = b;
            bitk = k;
            z.avail_in = n;
            z.total_in += p - z.next_in_index;
            z.next_in_index = p;
            write = q;
            return inflate_flush(r);
          }

          index = 0;
          mode = DTREE;
        case DTREE:
          while (true) {
            t = table;
            if (!(index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f))) {
              break;
            }

            int[] h;
            int i, j, c;

            t = bb[0];

            while (k < (t)) {
              if (n != 0) {
                r = Z_OK;
              } else {
                bitb = b;
                bitk = k;
                z.avail_in = n;
                z.total_in += p - z.next_in_index;
                z.next_in_index = p;
                write = q;
                return inflate_flush(r);
              }
              n--;
              b |= (z.next_in[p++] & 0xff) << k;
              k += 8;
            }

            if (tb[0] == -1) {
              // System.err.println("null...");
            }

            t = hufts[(tb[0] + (b & inflate_mask[t])) * 3 + 1];
            c = hufts[(tb[0] + (b & inflate_mask[t])) * 3 + 2];

            if (c < 16) {
              b >>>= (t);
              k -= (t);
              blens[index++] = c;
            } else { // c == 16..18
              i = c == 18 ? 7 : c - 14;
              j = c == 18 ? 11 : 3;

              while (k < (t + i)) {
                if (n != 0) {
                  r = Z_OK;
                } else {
                  bitb = b;
                  bitk = k;
                  z.avail_in = n;
                  z.total_in += p - z.next_in_index;
                  z.next_in_index = p;
                  write = q;
                  return inflate_flush(r);
                }
                n--;
                b |= (z.next_in[p++] & 0xff) << k;
                k += 8;
              }

              b >>>= (t);
              k -= (t);

              j += (b & inflate_mask[i]);

              b >>>= (i);
              k -= (i);

              i = index;
              t = table;
              if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) || (c == 16 && i < 1)) {
                blens = null;
                mode = BAD;
                z.msg = "invalid bit length repeat";
                r = Z_DATA_ERROR;

                bitb = b;
                bitk = k;
                z.avail_in = n;
                z.total_in += p - z.next_in_index;
                z.next_in_index = p;
                write = q;
                return inflate_flush(r);
              }

              c = c == 16 ? blens[i - 1] : 0;
              do {
                blens[i++] = c;
              } while (--j != 0);
              index = i;
            }
          }

          tb[0] = -1;
          {
            bl[0] = 9; // must be <= 9 for lookahead assumptions
            bd[0] = 6; // must be <= 9 for lookahead assumptions
            t = table;
            t = inftree.inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f), blens, bl, bd,
                tli, tdi, hufts, z);

            if (t != Z_OK) {
              if (t == Z_DATA_ERROR) {
                blens = null;
                mode = BAD;
              }
              r = t;

              bitb = b;
              bitk = k;
              z.avail_in = n;
              z.total_in += p - z.next_in_index;
              z.next_in_index = p;
              write = q;
              return inflate_flush(r);
            }
            codes.init(bl[0], bd[0], hufts, tli[0], hufts, tdi[0]);
          }
          mode = CODES;
        case CODES:
          bitb = b;
          bitk = k;
          z.avail_in = n;
          z.total_in += p - z.next_in_index;
          z.next_in_index = p;
          write = q;

          if ((r = codes.proc(r)) != Z_STREAM_END) {
            return inflate_flush(r);
          }
          r = Z_OK;
          codes.free(z);

          p = z.next_in_index;
          n = z.avail_in;
          b = bitb;
          k = bitk;
          q = write;
          m = (q < read ? read - q - 1 : end - q);

          if (last == 0) {
            mode = TYPE;
            break;
          }
          mode = DRY;
        case DRY:
          write = q;
          r = inflate_flush(r);
          q = write;
          m = (q < read ? read - q - 1 : end - q);
          if (read != write) {
            bitb = b;
            bitk = k;
            z.avail_in = n;
            z.total_in += p - z.next_in_index;
            z.next_in_index = p;
            write = q;
            return inflate_flush(r);
          }
          mode = DONE;
        case DONE:
          r = Z_STREAM_END;

          bitb = b;
          bitk = k;
          z.avail_in = n;
          z.total_in += p - z.next_in_index;
          z.next_in_index = p;
          write = q;
          return inflate_flush(r);
        case BAD:
          r = Z_DATA_ERROR;

          bitb = b;
          bitk = k;
          z.avail_in = n;
          z.total_in += p - z.next_in_index;
          z.next_in_index = p;
          write = q;
          return inflate_flush(r);

        default:
          r = Z_STREAM_ERROR;

          bitb = b;
          bitk = k;
          z.avail_in = n;
          z.total_in += p - z.next_in_index;
          z.next_in_index = p;
          write = q;
          return inflate_flush(r);
      }
    }
  }

  void free() {
    reset();
    window = null;
    hufts = null;
    // ZFREE(z, s);
  }

  void set_dictionary(byte[] d, int start, int n) {
    System.arraycopy(d, start, window, 0, n);
    read = write = n;
  }

  // Returns true if inflate is currently at the end of a block generated
  // by Z_SYNC_FLUSH or Z_FULL_FLUSH.
  int sync_point() {
    return mode == LENS ? 1 : 0;
  }

  // copy as much as possible from the sliding window to the output area
  int inflate_flush(int r) {
    int n;
    int p;
    int q;

    // local copies of source and destination pointers
    p = z.next_out_index;
    q = read;

    // compute number of bytes to copy as far as end of window
    n = ((q <= write ? write : end) - q);
    if (n > z.avail_out)
      n = z.avail_out;
    if (n != 0 && r == Z_BUF_ERROR)
      r = Z_OK;

    // update counters
    z.avail_out -= n;
    z.total_out += n;

    // update check information
    if (check && n > 0) {
      z.adler.update(window, q, n);
    }

    // copy as far as end of window
    System.arraycopy(window, q, z.next_out, p, n);
    p += n;
    q += n;

    // see if more to copy at beginning of window
    if (q == end) {
      // wrap pointers
      q = 0;
      if (write == end)
        write = 0;

      // compute bytes to copy
      n = write - q;
      if (n > z.avail_out)
        n = z.avail_out;
      if (n != 0 && r == Z_BUF_ERROR)
        r = Z_OK;

      // update counters
      z.avail_out -= n;
      z.total_out += n;

      // update check information
      if (check && n > 0) {
        z.adler.update(window, q, n);
      }

      // copy
      System.arraycopy(window, q, z.next_out, p, n);
      p += n;
      q += n;
    }

    // update pointers
    z.next_out_index = p;
    read = q;

    // done
    return r;
  }
}
