infcodes.java

纯Java实现的ZIP文件压缩解压类库,JDK中的ZIP类库源码中有一些native方法

/* -*-mode:java; c-basic-offset:2; -*- */
/*
Copyright (c) 2000,2001,2002,2003 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([e-mail]) and Mark Adler([e-mail])
 * and contributors of zlib.
 */

package com.jcraft.jzlib;

final class InfCodes{

  static final private int[] inflate_mask = {
    0x00000000, 0x00000001, 0x00000003, 0x00000007, 0x0000000f,
    0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 0x000001ff,
    0x000003ff, 0x000007ff, 0x00000fff, 0x00001fff, 0x00003fff,
    0x00007fff, 0x0000ffff
  };

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

  // waiting for "i:"=input,
  //             "o:"=output,
  //             "x:"=nothing
  static final private int START=0;  // x: set up for LEN
  static final private int LEN=1;    // i: get length/literal/eob next
  static final private int LENEXT=2; // i: getting length extra (have base)
  static final private int DIST=3;   // i: get distance next
  static final private int DISTEXT=4;// i: getting distance extra
  static final private int COPY=5;   // o: copying bytes in window, waiting for space
  static final private int LIT=6;    // o: got literal, waiting for output space
  static final private int WASH=7;   // o: got eob, possibly still output waiting
  static final private int END=8;    // x: got eob and all data flushed
  static final private int BADCODE=9;// x: got error

  int mode;      // current inflate_codes mode

  // mode dependent information
  int len;

  int[] tree; // pointer into tree
  int tree_index=0;
  int need;   // bits needed

  int lit;

  // if EXT or COPY, where and how much
  int get;              // bits to get for extra
  int dist;             // distance back to copy from

  byte lbits;           // ltree bits decoded per branch
  byte dbits;           // dtree bits decoder per branch
  int[] ltree;          // literal/length/eob tree
  int ltree_index;      // literal/length/eob tree
  int[] dtree;          // distance tree
  int dtree_index;      // distance tree

  InfCodes(){
  }
  void init(int bl, int bd,
	   int[] tl, int tl_index,
	   int[] td, int td_index, ZStream z){
    mode=START;
    lbits=(byte)bl;
    dbits=(byte)bd;
    ltree=tl;
    ltree_index=tl_index;
    dtree = td;
    dtree_index=td_index;
    tree=null;
  }

  int proc(InfBlocks s, ZStream z, int r){ 
    int j;              // temporary storage
    int[] t;            // temporary pointer
    int tindex;         // temporary pointer
    int e;              // extra bits or operation
    int b=0;            // bit buffer
    int k=0;            // bits in bit buffer
    int p=0;            // input data pointer
    int n;              // bytes available there
    int q;              // output window write pointer
    int m;              // bytes to end of window or read pointer
    int f;              // pointer to copy strings from

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

    // process input and output based on current state
    while (true){
      switch (mode){
	// waiting for "i:"=input, "o:"=output, "x:"=nothing
      case START:         // x: set up for LEN
	if (m >= 258 && n >= 10){

	  s.bitb=b;s.bitk=k;
	  z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
	  s.write=q;
	  r = inflate_fast(lbits, dbits, 
			   ltree, ltree_index, 
			   dtree, dtree_index,
			   s, z);

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

	  if (r != Z_OK){
	    mode = r == Z_STREAM_END ? WASH : BADCODE;
	    break;
	  }
	}
	need = lbits;
	tree = ltree;
	tree_index=ltree_index;

	mode = LEN;
      case LEN:           // i: get length/literal/eob next
	j = need;

	while(k<(j)){
	  if(n!=0)r=Z_OK;
	  else{

	    s.bitb=b;s.bitk=k;
	    z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
	    s.write=q;
	    return s.inflate_flush(z,r);
	  }
	  n--;
	  b|=(z.next_in[p++]&0xff)<<k;
	  k+=8;
	}

	tindex=(tree_index+(b&inflate_mask[j]))*3;

	b>>>=(tree[tindex+1]);
	k-=(tree[tindex+1]);

	e=tree[tindex];

	if(e == 0){               // literal
	  lit = tree[tindex+2];
	  mode = LIT;
	  break;
	}
	if((e & 16)!=0 ){          // length
	  get = e & 15;
	  len = tree[tindex+2];
	  mode = LENEXT;
	  break;
	}
	if ((e & 64) == 0){        // next table
	  need = e;
	  tree_index = tindex/3+tree[tindex+2];
	  break;
	}
	if ((e & 32)!=0){               // end of block
	  mode = WASH;
	  break;
	}
	mode = BADCODE;        // invalid code
	z.msg = "invalid literal/length code";
	r = Z_DATA_ERROR;

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

      case LENEXT:        // i: getting length extra (have base)
	j = get;

	while(k<(j)){
	  if(n!=0)r=Z_OK;
	  else{

	    s.bitb=b;s.bitk=k;
	    z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
	    s.write=q;
	    return s.inflate_flush(z,r);
	  }
	  n--; b|=(z.next_in[p++]&0xff)<<k;
	  k+=8;
	}

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

	b>>=j;
	k-=j;

	need = dbits;
	tree = dtree;
	tree_index=dtree_index;
	mode = DIST;
      case DIST:          // i: get distance next
	j = need;

	while(k<(j)){
	  if(n!=0)r=Z_OK;
	  else{

	    s.bitb=b;s.bitk=k;
	    z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
	    s.write=q;
	    return s.inflate_flush(z,r);
	  }
	  n--; b|=(z.next_in[p++]&0xff)<<k;
	  k+=8;
	}

	tindex=(tree_index+(b & inflate_mask[j]))*3;

	b>>=tree[tindex+1];
	k-=tree[tindex+1];

	e = (tree[tindex]);
	if((e & 16)!=0){               // distance
	  get = e & 15;
	  dist = tree[tindex+2];
	  mode = DISTEXT;
	  break;
	}
	if ((e & 64) == 0){        // next table
	  need = e;
	  tree_index = tindex/3 + tree[tindex+2];
	  break;
	}
	mode = BADCODE;        // invalid code
	z.msg = "invalid distance code";
	r = Z_DATA_ERROR;

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

      case DISTEXT:       // i: getting distance extra
	j = get;

	while(k<(j)){
	  if(n!=0)r=Z_OK;
	  else{

	    s.bitb=b;s.bitk=k;
	    z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
	    s.write=q;
	    return s.inflate_flush(z,r);
	  }
	  n--; b|=(z.next_in[p++]&0xff)<<k;
	  k+=8;
	}

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

	b>>=j;
	k-=j;

	mode = COPY;
      case COPY:          // o: copying bytes in window, waiting for space
        f = q - dist;
        while(f < 0){     // modulo window size-"while" instead
          f += s.end;     // of "if" handles invalid distances
	}
	while (len!=0){

	  if(m==0){
	    if(q==s.end&&s.read!=0){q=0;m=q<s.read?s.read-q-1:s.end-q;}
	    if(m==0){