deflate.java

来自「zlib 算法在j2me 中的应用」· Java 代码 · 共 1,764 行 · 第 1/5 页

  }
  int deflateInit2(ZStream strm, int level, int method,  int windowBits,
		   int memLevel, int strategy){
    int noheader = 0;
    //    byte[] my_version=ZLIB_VERSION;

    //
    //  if (version == null || version[0] != my_version[0]
    //  || stream_size != sizeof(z_stream)) {
    //  return Z_VERSION_ERROR;
    //  }

    strm.msg = null;

    if (level == Z_DEFAULT_COMPRESSION) level = 6;

    if (windowBits < 0) { // undocumented feature: suppress zlib header
      noheader = 1;
      windowBits = -windowBits;
    }

    if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || 
	method != Z_DEFLATED ||
	windowBits < 9 || windowBits > 15 || level < 0 || level > 9 ||
        strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
      return Z_STREAM_ERROR;
    }

    strm.dstate = (Deflate)this;

    this.noheader = noheader;
    w_bits = windowBits;
    w_size = 1 << w_bits;
    w_mask = w_size - 1;

    hash_bits = memLevel + 7;
    hash_size = 1 << hash_bits;
    hash_mask = hash_size - 1;
    hash_shift = ((hash_bits+MIN_MATCH-1)/MIN_MATCH);

    window = new_byte(w_size*2,500,"window");
    prev = new_short2(w_size,256,"prev");
    head = new_short2(hash_size,256,"head");//32kb not depend on amount of data


   
   
    lit_bufsize = 1 << (memLevel + 6); // 16K elements by default

    // We overlay pending_buf and d_buf+l_buf. This works since the average
    // output size for (length,distance) codes is <= 24 bits.
    pending_buf = new_byte(lit_bufsize*4,500,"pending_buf");
    pending_buf_size = lit_bufsize*4;

    d_buf = lit_bufsize/2;
    l_buf = (1+2)*lit_bufsize;

    this.level = level;

//System.out.println("level="+level);

    this.strategy = strategy;
    this.method = (byte)method;

    return deflateReset(strm);
  }

  int deflateReset(ZStream strm){
    strm.total_in = strm.total_out = 0;
    strm.msg = null; //
    strm.data_type = Z_UNKNOWN;

    pending = 0;
    pending_out = 0;

    if(noheader < 0) {
      noheader = 0; // was set to -1 by deflate(..., Z_FINISH);
    }
    status = (noheader!=0) ? BUSY_STATE : INIT_STATE;
    strm.adler=strm._adler.adler32(0, (byte_array)null, 0, 0);

    last_flush = Z_NO_FLUSH;

    tr_init();
    lm_init();
    return Z_OK;
  }

  int deflateEnd(){
    if(status!=INIT_STATE && status!=BUSY_STATE && status!=FINISH_STATE){
      return Z_STREAM_ERROR;
    }
    // Deallocate in reverse order of allocations:
    pending_buf=null;
    head=null;
    prev=null;
    window=null;
    // free
    // dstate=null;
    return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
  }

  int deflateParams(ZStream strm, int _level, int _strategy){
    int err=Z_OK;

    if(_level == Z_DEFAULT_COMPRESSION){
      _level = 6;
    }
    if(_level < 0 || _level > 9 || 
       _strategy < 0 || _strategy > Z_HUFFMAN_ONLY) {
      return Z_STREAM_ERROR;
    }

    if(config_table[level].func!=config_table[_level].func &&
       strm.total_in != 0) {
      // Flush the last buffer:
      err = strm.deflate(Z_PARTIAL_FLUSH);
    }

    if(level != _level) {
      level = _level;
      max_lazy_match   = config_table[level].max_lazy;
      good_match       = config_table[level].good_length;
      nice_match       = config_table[level].nice_length;
      max_chain_length = config_table[level].max_chain;
    }
    strategy = _strategy;
    return err;
  }

  int deflateSetDictionary (ZStream strm, byte[] dictionary, int dictLength){
    int length = dictLength;
    int index=0;

    if(dictionary == null || status != INIT_STATE)
      return Z_STREAM_ERROR;

    strm.adler=strm._adler.adler32(strm.adler, dictionary, 0, dictLength);

    if(length < MIN_MATCH) return Z_OK;
    if(length > w_size-MIN_LOOKAHEAD){
      length = w_size-MIN_LOOKAHEAD;
      index=dictLength-length; // use the tail of the dictionary
    }
    //System.arraycopy(dictionary, index, window, 0, length);
    byte_array.Copy(dictionary, index, window, 0, length);
    strstart = length;
    block_start = length;

    // Insert all strings in the hash table (except for the last two bytes).
    // s->lookahead stays null, so s->ins_h will be recomputed at the next
    // call of fill_window.

    //ins_h = window[0]&0xff;
    //ins_h=(((ins_h)<<hash_shift)^(window[1]&0xff))&hash_mask;
    ins_h = window.get(0)&0xff;
    ins_h=(((ins_h)<<hash_shift)^(window.get(1)&0xff))&hash_mask;    

    for(int n=0; n<=length-MIN_MATCH; n++){
      //ins_h=(((ins_h)<<hash_shift)^(window[(n)+(MIN_MATCH-1)]&0xff))&hash_mask;
      ins_h=(((ins_h)<<hash_shift)^(window.get((n)+(MIN_MATCH-1))&0xff))&hash_mask;      
      //prev[n&w_mask]=head[ins_h];
      prev.set(n&w_mask,head.get(ins_h));
      //head[ins_h]=(short)n;
      head.set(ins_h,(short)n);
    }
    return Z_OK;
  }

  int deflate(ZStream strm, int flush){
    int old_flush;

    if(flush>Z_FINISH || flush<0){
      return Z_STREAM_ERROR;
    }

    if(strm.next_out == null ||
       (strm.next_in == null && strm.avail_in != 0) ||
       (status == FINISH_STATE && flush != Z_FINISH)) {
      strm.msg=z_errmsg[Z_NEED_DICT-(Z_STREAM_ERROR)];
      return Z_STREAM_ERROR;
    }
    if(strm.avail_out == 0){
      strm.msg=z_errmsg[Z_NEED_DICT-(Z_BUF_ERROR)];
      return Z_BUF_ERROR;
    }

    this.strm = strm; // just in case
    old_flush = last_flush;
    last_flush = flush;

    // Write the zlib header
    if(status == INIT_STATE) {
      int header = (Z_DEFLATED+((w_bits-8)<<4))<<8;
      int level_flags=((level-1)&0xff)>>1;

      if(level_flags>3) level_flags=3;
      header |= (level_flags<<6);
      if(strstart!=0) header |= PRESET_DICT;
      header+=31-(header % 31);

      status=BUSY_STATE;
      putShortMSB(header);


      // Save the adler32 of the preset dictionary:
      if(strstart!=0){
        putShortMSB((int)(strm.adler>>>16));
        putShortMSB((int)(strm.adler&0xffff));
      }
      strm.adler=strm._adler.adler32(0, (byte_array)null, 0, 0);
    }

    // Flush as much pending output as possible
    if(pending != 0) {
      strm.flush_pending();
      if(strm.avail_out == 0) {
	//System.out.println("  avail_out==0");
	// Since avail_out is 0, deflate will be called again with
	// more output space, but possibly with both pending and
	// avail_in equal to zero. There won't be anything to do,
	// but this is not an error situation so make sure we
	// return OK instead of BUF_ERROR at next call of deflate:
	last_flush = -1;
	return Z_OK;
      }

      // Make sure there is something to do and avoid duplicate consecutive
      // flushes. For repeated and useless calls with Z_FINISH, we keep
      // returning Z_STREAM_END instead of Z_BUFF_ERROR.
    }
    else if(strm.avail_in==0 && flush <= old_flush &&
	    flush != Z_FINISH) {
      strm.msg=z_errmsg[Z_NEED_DICT-(Z_BUF_ERROR)];
      return Z_BUF_ERROR;
    }

    // User must not provide more input after the first FINISH:
    if(status == FINISH_STATE && strm.avail_in != 0) {
      strm.msg=z_errmsg[Z_NEED_DICT-(Z_BUF_ERROR)];
      return Z_BUF_ERROR;
    }

    // Start a new block or continue the current one.
    if(strm.avail_in!=0 || lookahead!=0 ||
       (flush != Z_NO_FLUSH && status != FINISH_STATE)) {
      int bstate=-1;
      switch(config_table[level].func){
      case STORED: 
	bstate = deflate_stored(flush);
	break;
      case FAST: 
	bstate = deflate_fast(flush);
	break;
      case SLOW: 
	bstate = deflate_slow(flush);
	break;
      default:
      }

      if (bstate==FinishStarted || bstate==FinishDone) {
	status = FINISH_STATE;
      }
      if (bstate==NeedMore || bstate==FinishStarted) {
	if(strm.avail_out == 0) {
	  last_flush = -1; // avoid BUF_ERROR next call, see above
	}
	return Z_OK;
	// If flush != Z_NO_FLUSH && avail_out == 0, the next call
	// of deflate should use the same flush parameter to make sure
	// that the flush is complete. So we don't have to output an
	// empty block here, this will be done at next call. This also
	// ensures that for a very small output buffer, we emit at most
	// one empty block.
      }

      if (bstate==BlockDone) {
	if(flush == Z_PARTIAL_FLUSH) {
	  _tr_align();
	} 
	else { // FULL_FLUSH or SYNC_FLUSH
	  _tr_stored_block(0, 0, false);
	  // For a full flush, this empty block will be recognized
	  // as a special marker by inflate_sync().
	  if(flush == Z_FULL_FLUSH) {
	    //state.head[s.hash_size-1]=0; was originally commented
	    for(int i=0; i<hash_size/*-1*/; i++){  // forget history
	      //head[i]=0;
                    head.set(i,(short)0);
	    }//for
	  }
	}
	strm.flush_pending();
	if(strm.avail_out == 0) {
	  last_flush = -1; // avoid BUF_ERROR at next call, see above
	  return Z_OK;
	}
      }
    }

    if(flush!=Z_FINISH) return Z_OK;
    if(noheader!=0) return Z_STREAM_END;

    // Write the zlib trailer (adler32)
    putShortMSB((int)(strm.adler>>>16));
    putShortMSB((int)(strm.adler&0xffff));
    strm.flush_pending();

    // If avail_out is zero, the application will call deflate again
    // to flush the rest.
    noheader = -1; // write the trailer only once!
    return pending != 0 ? Z_OK : Z_STREAM_END;
  }
//-------------------------------------------------------------------
  // protected void finalize(){
  //    //-------
  //    if(DEBUG>0){
  //     if(depth!=null)System.out.println("Deflate.finalize() depth.totalAllocated()="+depth.totalAllocated());
  //     if(window!=null)System.out.println("Deflate.finalize() window.totalAllocated()="+window.totalAllocated());
  //     if(prev!=null)System.out.println("Deflate.finalize() prev.totalAllocated()="+prev.totalAllocated());
  //     if(head!=null)System.out.println("Deflate.finalize() head.totalAllocated()="+head.totalAllocated());
  //     if(pending_buf!=null)System.out.println("Deflate.finalize() pending_buf.totalAllocated()="+pending_buf.totalAllocated());
  //    }//if(DEBUG>0)
  //    //-------   
  // }

  
 private static final int[] new_int(int len, String name){
  System.out.println("Array of "+name+" = new int["+len+"] allocated in Deflate");   
  return new int[len];
 }
 private static final short[] new_short(int len, String name){
  System.out.println("Array of "+name+" = new short["+len+"] allocated in Deflate");
  return new short[len];
 }

 private static final short_array new_short2(int len,int blocklen,String name){
  System.out.println("Dynamic array of "+name+" = new short["+len+"] allocated in Deflate");
  return new short_array(len,blocklen,"Deflate."+name);
 }  
  
 private static final byte_array new_byte(int len, int blocklen, String name){
  System.out.println("Dynamic array of "+name+" = new byte["+len+"] allocated in Deflate");   
  return new byte_array(len,blocklen,"Deflate."+name);
 }  
  //byte0(int len,String name){
  //   System.out.println("Array of "+name+" = new byte["+len+"] allocated in Deflate");   
  //   return new byte[len];
  //  }  
//-------------------------------------------------------------------  
}