src/com/jcraft/jzlib/InfCodes.java

   1 /* -*-mode:java; c-basic-offset:2; -*- */
   2 /*
   3 Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved.
   4
   5 Redistribution and use in source and binary forms, with or without
   6 modification, are permitted provided that the following conditions are met:
   7
   8   1. Redistributions of source code must retain the above copyright notice,
   9      this list of conditions and the following disclaimer.
  10
  11   2. Redistributions in binary form must reproduce the above copyright
  12      notice, this list of conditions and the following disclaimer in
  13      the documentation and/or other materials provided with the distribution.
  14
  15   3. The names of the authors may not be used to endorse or promote products
  16      derived from this software without specific prior written permission.
  17
  18 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
  19 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  20 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
  21 INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
  22 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  23 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
  24 OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  25 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  26 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  27 EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29 /*
  30  * This program is based on zlib-1.1.3, so all credit should go authors
  31  * Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu)
  32  * and contributors of zlib.
  33  */
  34
  35 package com.jcraft.jzlib;
  36
  37 final class InfCodes{
  38
  39   static final private int[] inflate_mask = {
  40     0x00000000, 0x00000001, 0x00000003, 0x00000007, 0x0000000f,
  41     0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 0x000001ff,
  42     0x000003ff, 0x000007ff, 0x00000fff, 0x00001fff, 0x00003fff,
  43     0x00007fff, 0x0000ffff
  44   };
  45
  46   static final private int Z_OK=0;
  47   static final private int Z_STREAM_END=1;
  48   static final private int Z_NEED_DICT=2;
  49   static final private int Z_ERRNO=-1;
  50   static final private int Z_STREAM_ERROR=-2;
  51   static final private int Z_DATA_ERROR=-3;
  52   static final private int Z_MEM_ERROR=-4;
  53   static final private int Z_BUF_ERROR=-5;
  54   static final private int Z_VERSION_ERROR=-6;
  55
  56   // waiting for "i:"=input,
  57   //             "o:"=output,
  58   //             "x:"=nothing
  59   static final private int START=0;  // x: set up for LEN
  60   static final private int LEN=1;    // i: get length/literal/eob next
  61   static final private int LENEXT=2; // i: getting length extra (have base)
  62   static final private int DIST=3;   // i: get distance next
  63   static final private int DISTEXT=4;// i: getting distance extra
  64   static final private int COPY=5;   // o: copying bytes in window, waiting for space
  65   static final private int LIT=6;    // o: got literal, waiting for output space
  66   static final private int WASH=7;   // o: got eob, possibly still output waiting
  67   static final private int END=8;    // x: got eob and all data flushed
  68   static final private int BADCODE=9;// x: got error
  69
  70   int mode;      // current inflate_codes mode
  71
  72   // mode dependent information
  73   int len;
  74
  75   int[] tree; // pointer into tree
  76   int tree_index=0;
  77   int need;   // bits needed
  78
  79   int lit;
  80
  81   // if EXT or COPY, where and how much
  82   int get;              // bits to get for extra
  83   int dist;             // distance back to copy from
  84
  85   byte lbits;           // ltree bits decoded per branch
  86   byte dbits;           // dtree bits decoder per branch
  87   int[] ltree;          // literal/length/eob tree
  88   int ltree_index;      // literal/length/eob tree
  89   int[] dtree;          // distance tree
  90   int dtree_index;      // distance tree
  91
  92   InfCodes(){
  93   }
  94   void init(int bl, int bd,
  95            int[] tl, int tl_index,
  96            int[] td, int td_index, ZStream z){
  97     mode=START;
  98     lbits=(byte)bl;
  99     dbits=(byte)bd;
 100     ltree=tl;
 101     ltree_index=tl_index;
 102     dtree = td;
 103     dtree_index=td_index;
 104     tree=null;
 105   }
 106
 107   int proc(InfBlocks s, ZStream z, int r){
 108     int j;              // temporary storage
 109     int[] t;            // temporary pointer
 110     int tindex;         // temporary pointer
 111     int e;              // extra bits or operation
 112     int b=0;            // bit buffer
 113     int k=0;            // bits in bit buffer
 114     int p=0;            // input data pointer
 115     int n;              // bytes available there
 116     int q;              // output window write pointer
 117     int m;              // bytes to end of window or read pointer
 118     int f;              // pointer to copy strings from
 119
 120     // copy input/output information to locals (UPDATE macro restores)
 121     p=z.next_in_index;n=z.avail_in;b=s.bitb;k=s.bitk;
 122     q=s.write;m=q<s.read?s.read-q-1:s.end-q;
 123
 124     // process input and output based on current state
 125     while (true){
 126       switch (mode){
 127         // waiting for "i:"=input, "o:"=output, "x:"=nothing
 128       case START:         // x: set up for LEN
 129         if (m >= 258 && n >= 10){
 130
 131           s.bitb=b;s.bitk=k;
 132           z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 133           s.write=q;
 134           r = inflate_fast(lbits, dbits,
 135                            ltree, ltree_index,
 136                            dtree, dtree_index,
 137                            s, z);
 138
 139           p=z.next_in_index;n=z.avail_in;b=s.bitb;k=s.bitk;
 140           q=s.write;m=q<s.read?s.read-q-1:s.end-q;
 141
 142           if (r != Z_OK){
 143             mode = r == Z_STREAM_END ? WASH : BADCODE;
 144             break;
 145           }
 146         }
 147         need = lbits;
 148         tree = ltree;
 149         tree_index=ltree_index;
 150
 151         mode = LEN;
 152       case LEN:           // i: get length/literal/eob next
 153         j = need;
 154
 155         while(k<(j)){
 156           if(n!=0)r=Z_OK;
 157           else{
 158
 159             s.bitb=b;s.bitk=k;
 160             z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 161             s.write=q;
 162             return s.inflate_flush(z,r);
 163           }
 164           n--;
 165           b|=(z.next_in[p++]&0xff)<<k;
 166           k+=8;
 167         }
 168
 169         tindex=(tree_index+(b&inflate_mask[j]))*3;
 170
 171         b>>>=(tree[tindex+1]);
 172         k-=(tree[tindex+1]);
 173
 174         e=tree[tindex];
 175
 176         if(e == 0){               // literal
 177           lit = tree[tindex+2];
 178           mode = LIT;
 179           break;
 180         }
 181         if((e & 16)!=0 ){          // length
 182           get = e & 15;
 183           len = tree[tindex+2];
 184           mode = LENEXT;
 185           break;
 186         }
 187         if ((e & 64) == 0){        // next table
 188           need = e;
 189           tree_index = tindex/3+tree[tindex+2];
 190           break;
 191         }
 192         if ((e & 32)!=0){               // end of block
 193           mode = WASH;
 194           break;
 195         }
 196         mode = BADCODE;        // invalid code
 197         z.msg = "invalid literal/length code";
 198         r = Z_DATA_ERROR;
 199
 200         s.bitb=b;s.bitk=k;
 201         z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 202         s.write=q;
 203         return s.inflate_flush(z,r);
 204
 205       case LENEXT:        // i: getting length extra (have base)
 206         j = get;
 207
 208         while(k<(j)){
 209           if(n!=0)r=Z_OK;
 210           else{
 211
 212             s.bitb=b;s.bitk=k;
 213             z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 214             s.write=q;
 215             return s.inflate_flush(z,r);
 216           }
 217           n--; b|=(z.next_in[p++]&0xff)<<k;
 218           k+=8;
 219         }
 220
 221         len += (b & inflate_mask[j]);
 222
 223         b>>=j;
 224         k-=j;
 225
 226         need = dbits;
 227         tree = dtree;
 228         tree_index=dtree_index;
 229         mode = DIST;
 230       case DIST:          // i: get distance next
 231         j = need;
 232
 233         while(k<(j)){
 234           if(n!=0)r=Z_OK;
 235           else{
 236
 237             s.bitb=b;s.bitk=k;
 238             z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 239             s.write=q;
 240             return s.inflate_flush(z,r);
 241           }
 242           n--; b|=(z.next_in[p++]&0xff)<<k;
 243           k+=8;
 244         }
 245
 246         tindex=(tree_index+(b & inflate_mask[j]))*3;
 247
 248         b>>=tree[tindex+1];
 249         k-=tree[tindex+1];
 250
 251         e = (tree[tindex]);
 252         if((e & 16)!=0){               // distance
 253           get = e & 15;
 254           dist = tree[tindex+2];
 255           mode = DISTEXT;
 256           break;
 257         }
 258         if ((e & 64) == 0){        // next table
 259           need = e;
 260           tree_index = tindex/3 + tree[tindex+2];
 261           break;
 262         }
 263         mode = BADCODE;        // invalid code
 264         z.msg = "invalid distance code";
 265         r = Z_DATA_ERROR;
 266
 267         s.bitb=b;s.bitk=k;
 268         z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 269         s.write=q;
 270         return s.inflate_flush(z,r);
 271
 272       case DISTEXT:       // i: getting distance extra
 273         j = get;
 274
 275         while(k<(j)){
 276           if(n!=0)r=Z_OK;
 277           else{
 278
 279             s.bitb=b;s.bitk=k;
 280             z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 281             s.write=q;
 282             return s.inflate_flush(z,r);
 283           }
 284           n--; b|=(z.next_in[p++]&0xff)<<k;
 285           k+=8;
 286         }
 287
 288         dist += (b & inflate_mask[j]);
 289
 290         b>>=j;
 291         k-=j;
 292
 293         mode = COPY;
 294       case COPY:          // o: copying bytes in window, waiting for space
 295         f = q - dist;
 296         while(f < 0){     // modulo window size-"while" instead
 297           f += s.end;     // of "if" handles invalid distances
 298         }
 299         while (len!=0){
 300
 301           if(m==0){
 302             if(q==s.end&&s.read!=0){q=0;m=q<s.read?s.read-q-1:s.end-q;}
 303             if(m==0){
 304               s.write=q; r=s.inflate_flush(z,r);
 305               q=s.write;m=q<s.read?s.read-q-1:s.end-q;
 306
 307               if(q==s.end&&s.read!=0){q=0;m=q<s.read?s.read-q-1:s.end-q;}
 308
 309               if(m==0){
 310                 s.bitb=b;s.bitk=k;
 311                 z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 312                 s.write=q;
 313                 return s.inflate_flush(z,r);
 314               }
 315             }
 316           }
 317
 318           s.window[q++]=s.window[f++]; m--;
 319
 320           if (f == s.end)
 321             f = 0;
 322           len--;
 323         }
 324         mode = START;
 325         break;
 326       case LIT:           // o: got literal, waiting for output space
 327         if(m==0){
 328           if(q==s.end&&s.read!=0){q=0;m=q<s.read?s.read-q-1:s.end-q;}
 329           if(m==0){
 330             s.write=q; r=s.inflate_flush(z,r);
 331             q=s.write;m=q<s.read?s.read-q-1:s.end-q;
 332
 333             if(q==s.end&&s.read!=0){q=0;m=q<s.read?s.read-q-1:s.end-q;}
 334             if(m==0){
 335               s.bitb=b;s.bitk=k;
 336               z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 337               s.write=q;
 338               return s.inflate_flush(z,r);
 339             }
 340           }
 341         }
 342         r=Z_OK;
 343
 344         s.window[q++]=(byte)lit; m--;
 345
 346         mode = START;
 347         break;
 348       case WASH:           // o: got eob, possibly more output
 349         if (k > 7){        // return unused byte, if any
 350           k -= 8;
 351           n++;
 352           p--;             // can always return one
 353         }
 354
 355         s.write=q; r=s.inflate_flush(z,r);
 356         q=s.write;m=q<s.read?s.read-q-1:s.end-q;
 357
 358         if (s.read != s.write){
 359           s.bitb=b;s.bitk=k;
 360           z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 361           s.write=q;
 362           return s.inflate_flush(z,r);
 363         }
 364         mode = END;
 365       case END:
 366         r = Z_STREAM_END;
 367         s.bitb=b;s.bitk=k;
 368         z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 369         s.write=q;
 370         return s.inflate_flush(z,r);
 371
 372       case BADCODE:       // x: got error
 373
 374         r = Z_DATA_ERROR;
 375
 376         s.bitb=b;s.bitk=k;
 377         z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 378         s.write=q;
 379         return s.inflate_flush(z,r);
 380
 381       default:
 382         r = Z_STREAM_ERROR;
 383
 384         s.bitb=b;s.bitk=k;
 385         z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 386         s.write=q;
 387         return s.inflate_flush(z,r);
 388       }
 389     }
 390   }
 391
 392   void free(ZStream z){
 393     //  ZFREE(z, c);
 394   }
 395
 396   // Called with number of bytes left to write in window at least 258
 397   // (the maximum string length) and number of input bytes available
 398   // at least ten.  The ten bytes are six bytes for the longest length/
 399   // distance pair plus four bytes for overloading the bit buffer.
 400
 401   int inflate_fast(int bl, int bd,
 402                    int[] tl, int tl_index,
 403                    int[] td, int td_index,
 404                    InfBlocks s, ZStream z){
 405     int t;                // temporary pointer
 406     int[] tp;             // temporary pointer
 407     int tp_index;         // temporary pointer
 408     int e;                // extra bits or operation
 409     int b;                // bit buffer
 410     int k;                // bits in bit buffer
 411     int p;                // input data pointer
 412     int n;                // bytes available there
 413     int q;                // output window write pointer
 414     int m;                // bytes to end of window or read pointer
 415     int ml;               // mask for literal/length tree
 416     int md;               // mask for distance tree
 417     int c;                // bytes to copy
 418     int d;                // distance back to copy from
 419     int r;                // copy source pointer
 420
 421     int tp_index_t_3;     // (tp_index+t)*3
 422
 423     // load input, output, bit values
 424     p=z.next_in_index;n=z.avail_in;b=s.bitb;k=s.bitk;
 425     q=s.write;m=q<s.read?s.read-q-1:s.end-q;
 426
 427     // initialize masks
 428     ml = inflate_mask[bl];
 429     md = inflate_mask[bd];
 430
 431     // do until not enough input or output space for fast loop
 432     do {                          // assume called with m >= 258 && n >= 10
 433       // get literal/length code
 434       while(k<(20)){              // max bits for literal/length code
 435         n--;
 436         b|=(z.next_in[p++]&0xff)<<k;k+=8;
 437       }
 438
 439       t= b&ml;
 440       tp=tl;
 441       tp_index=tl_index;
 442       tp_index_t_3=(tp_index+t)*3;
 443       if ((e = tp[tp_index_t_3]) == 0){
 444         b>>=(tp[tp_index_t_3+1]); k-=(tp[tp_index_t_3+1]);
 445
 446         s.window[q++] = (byte)tp[tp_index_t_3+2];
 447         m--;
 448         continue;
 449       }
 450       do {
 451
 452         b>>=(tp[tp_index_t_3+1]); k-=(tp[tp_index_t_3+1]);
 453
 454         if((e&16)!=0){
 455           e &= 15;
 456           c = tp[tp_index_t_3+2] + ((int)b & inflate_mask[e]);
 457
 458           b>>=e; k-=e;
 459
 460           // decode distance base of block to copy
 461           while(k<(15)){           // max bits for distance code
 462             n--;
 463             b|=(z.next_in[p++]&0xff)<<k;k+=8;
 464           }
 465
 466           t= b&md;
 467           tp=td;
 468           tp_index=td_index;
 469           tp_index_t_3=(tp_index+t)*3;
 470           e = tp[tp_index_t_3];
 471
 472           do {
 473
 474             b>>=(tp[tp_index_t_3+1]); k-=(tp[tp_index_t_3+1]);
 475
 476             if((e&16)!=0){
 477               // get extra bits to add to distance base
 478               e &= 15;
 479               while(k<(e)){         // get extra bits (up to 13)
 480                 n--;
 481                 b|=(z.next_in[p++]&0xff)<<k;k+=8;
 482               }
 483
 484               d = tp[tp_index_t_3+2] + (b&inflate_mask[e]);
 485
 486               b>>=(e); k-=(e);
 487
 488               // do the copy
 489               m -= c;
 490               if (q >= d){                // offset before dest
 491                 //  just copy
 492                 r=q-d;
 493                 if(q-r>0 && 2>(q-r)){
 494                   s.window[q++]=s.window[r++]; // minimum count is three,
 495                   s.window[q++]=s.window[r++]; // so unroll loop a little
 496                   c-=2;
 497                 }
 498                 else{
 499                   System.arraycopy(s.window, r, s.window, q, 2);
 500                   q+=2; r+=2; c-=2;
 501                 }
 502               }
 503               else{                  // else offset after destination
 504                 r=q-d;
 505                 do{
 506                   r+=s.end;          // force pointer in window
 507                 }while(r<0);         // covers invalid distances
 508                 e=s.end-r;
 509                 if(c>e){             // if source crosses,
 510                   c-=e;              // wrapped copy
 511                   if(q-r>0 && e>(q-r)){
 512                     do{s.window[q++] = s.window[r++];}
 513                     while(--e!=0);
 514                   }
 515                   else{
 516                     System.arraycopy(s.window, r, s.window, q, e);
 517                     q+=e; r+=e; e=0;
 518                   }
 519                   r = 0;                  // copy rest from start of window
 520                 }
 521
 522               }
 523
 524               // copy all or what's left
 525               if(q-r>0 && c>(q-r)){
 526                 do{s.window[q++] = s.window[r++];}
 527                 while(--c!=0);
 528               }
 529               else{
 530                 System.arraycopy(s.window, r, s.window, q, c);
 531                 q+=c; r+=c; c=0;
 532               }
 533               break;
 534             }
 535             else if((e&64)==0){
 536               t+=tp[tp_index_t_3+2];
 537               t+=(b&inflate_mask[e]);
 538               tp_index_t_3=(tp_index+t)*3;
 539               e=tp[tp_index_t_3];
 540             }
 541             else{
 542               z.msg = "invalid distance code";
 543
 544               c=z.avail_in-n;c=(k>>3)<c?k>>3:c;n+=c;p-=c;k-=c<<3;
 545
 546               s.bitb=b;s.bitk=k;
 547               z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 548               s.write=q;
 549
 550               return Z_DATA_ERROR;
 551             }
 552           }
 553           while(true);
 554           break;
 555         }
 556
 557         if((e&64)==0){
 558           t+=tp[tp_index_t_3+2];
 559           t+=(b&inflate_mask[e]);
 560           tp_index_t_3=(tp_index+t)*3;
 561           if((e=tp[tp_index_t_3])==0){
 562
 563             b>>=(tp[tp_index_t_3+1]); k-=(tp[tp_index_t_3+1]);
 564
 565             s.window[q++]=(byte)tp[tp_index_t_3+2];
 566             m--;
 567             break;
 568           }
 569         }
 570         else if((e&32)!=0){
 571
 572           c=z.avail_in-n;c=(k>>3)<c?k>>3:c;n+=c;p-=c;k-=c<<3;
 573
 574           s.bitb=b;s.bitk=k;
 575           z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 576           s.write=q;
 577
 578           return Z_STREAM_END;
 579         }
 580         else{
 581           z.msg="invalid literal/length code";
 582
 583           c=z.avail_in-n;c=(k>>3)<c?k>>3:c;n+=c;p-=c;k-=c<<3;
 584
 585           s.bitb=b;s.bitk=k;
 586           z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 587           s.write=q;
 588
 589           return Z_DATA_ERROR;
 590         }
 591       }
 592       while(true);
 593     }
 594     while(m>=258 && n>= 10);
 595
 596     // not enough input or output--restore pointers and return
 597     c=z.avail_in-n;c=(k>>3)<c?k>>3:c;n+=c;p-=c;k-=c<<3;
 598
 599     s.bitb=b;s.bitk=k;
 600     z.avail_in=n;z.total_in+=p-z.next_in_index;z.next_in_index=p;
 601     s.write=q;
 602
 603     return Z_OK;
 604   }
 605 }