SecurityServer/MacYarrow/zlib/inflate.c

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 /* inflate.c -- zlib interface to inflate modules
  20  * Copyright (C) 1995-1998 Mark Adler
  21  * For conditions of distribution and use, see copyright notice in zlib.h
  22  */
  23
  24 #include "zutil.h"
  25 #include "infblock.h"
  26
  27 struct inflate_blocks_state {int dummy;}; /* for buggy compilers */
  28
  29 typedef enum {
  30       METHOD,   /* waiting for method byte */
  31       FLAG,     /* waiting for flag byte */
  32       DICT4,    /* four dictionary check bytes to go */
  33       DICT3,    /* three dictionary check bytes to go */
  34       DICT2,    /* two dictionary check bytes to go */
  35       DICT1,    /* one dictionary check byte to go */
  36       DICT0,    /* waiting for inflateSetDictionary */
  37       BLOCKS,   /* decompressing blocks */
  38       CHECK4,   /* four check bytes to go */
  39       CHECK3,   /* three check bytes to go */
  40       CHECK2,   /* two check bytes to go */
  41       CHECK1,   /* one check byte to go */
  42       DONE,     /* finished check, done */
  43       BAD}      /* got an error--stay here */
  44 inflate_mode;
  45
  46 /* inflate private state */
  47 struct internal_state {
  48
  49   /* mode */
  50   inflate_mode  mode;   /* current inflate mode */
  51
  52   /* mode dependent information */
  53   union {
  54     uInt method;        /* if FLAGS, method byte */
  55     struct {
  56       uLong was;                /* computed check value */
  57       uLong need;               /* stream check value */
  58     } check;            /* if CHECK, check values to compare */
  59     uInt marker;        /* if BAD, inflateSync's marker bytes count */
  60   } sub;        /* submode */
  61
  62   /* mode independent information */
  63   int  nowrap;          /* flag for no wrapper */
  64   uInt wbits;           /* log2(window size)  (8..15, defaults to 15) */
  65   inflate_blocks_statef
  66     *blocks;            /* current inflate_blocks state */
  67
  68 };
  69
  70
  71 int ZEXPORT inflateReset(z)
  72 z_streamp z;
  73 {
  74   if (z == Z_NULL || z->state == Z_NULL)
  75     return Z_STREAM_ERROR;
  76   z->total_in = z->total_out = 0;
  77   z->msg = Z_NULL;
  78   z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
  79   inflate_blocks_reset(z->state->blocks, z, Z_NULL);
  80   Tracev((stderr, "inflate: reset\n"));
  81   return Z_OK;
  82 }
  83
  84
  85 int ZEXPORT inflateEnd(z)
  86 z_streamp z;
  87 {
  88   if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
  89     return Z_STREAM_ERROR;
  90   if (z->state->blocks != Z_NULL)
  91     inflate_blocks_free(z->state->blocks, z);
  92   ZFREE(z, z->state);
  93   z->state = Z_NULL;
  94   Tracev((stderr, "inflate: end\n"));
  95   return Z_OK;
  96 }
  97
  98
  99 int ZEXPORT inflateInit2_(z, w, version, stream_size)
 100 z_streamp z;
 101 int w;
 102 const char *version;
 103 int stream_size;
 104 {
 105   if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
 106       stream_size != sizeof(z_stream))
 107       return Z_VERSION_ERROR;
 108
 109   /* initialize state */
 110   if (z == Z_NULL)
 111     return Z_STREAM_ERROR;
 112   z->msg = Z_NULL;
 113   if (z->zalloc == Z_NULL)
 114   {
 115     z->zalloc = zcalloc;
 116     z->opaque = (voidpf)0;
 117   }
 118   if (z->zfree == Z_NULL) z->zfree = zcfree;
 119   if ((z->state = (struct internal_state FAR *)
 120        ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
 121     return Z_MEM_ERROR;
 122   z->state->blocks = Z_NULL;
 123
 124   /* handle undocumented nowrap option (no zlib header or check) */
 125   z->state->nowrap = 0;
 126   if (w < 0)
 127   {
 128     w = - w;
 129     z->state->nowrap = 1;
 130   }
 131
 132   /* set window size */
 133   if (w < 8 || w > 15)
 134   {
 135     inflateEnd(z);
 136     return Z_STREAM_ERROR;
 137   }
 138   z->state->wbits = (uInt)w;
 139
 140   /* create inflate_blocks state */
 141   if ((z->state->blocks =
 142       inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
 143       == Z_NULL)
 144   {
 145     inflateEnd(z);
 146     return Z_MEM_ERROR;
 147   }
 148   Tracev((stderr, "inflate: allocated\n"));
 149
 150   /* reset state */
 151   inflateReset(z);
 152   return Z_OK;
 153 }
 154
 155
 156 int ZEXPORT inflateInit_(z, version, stream_size)
 157 z_streamp z;
 158 const char *version;
 159 int stream_size;
 160 {
 161   return inflateInit2_(z, DEF_WBITS, version, stream_size);
 162 }
 163
 164
 165 #define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
 166 #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
 167
 168 int ZEXPORT inflate(z, f)
 169 z_streamp z;
 170 int f;
 171 {
 172   int r;
 173   uInt b;
 174
 175   if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL)
 176     return Z_STREAM_ERROR;
 177   f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
 178   r = Z_BUF_ERROR;
 179   while (1) switch (z->state->mode)
 180   {
 181     case METHOD:
 182       NEEDBYTE
 183       if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
 184       {
 185         z->state->mode = BAD;
 186         z->msg = (char*)"unknown compression method";
 187         z->state->sub.marker = 5;       /* can't try inflateSync */
 188         break;
 189       }
 190       if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
 191       {
 192         z->state->mode = BAD;
 193         z->msg = (char*)"invalid window size";
 194         z->state->sub.marker = 5;       /* can't try inflateSync */
 195         break;
 196       }
 197       z->state->mode = FLAG;
 198     case FLAG:
 199       NEEDBYTE
 200       b = NEXTBYTE;
 201       if (((z->state->sub.method << 8) + b) % 31)
 202       {
 203         z->state->mode = BAD;
 204         z->msg = (char*)"incorrect header check";
 205         z->state->sub.marker = 5;       /* can't try inflateSync */
 206         break;
 207       }
 208       Tracev((stderr, "inflate: zlib header ok\n"));
 209       if (!(b & PRESET_DICT))
 210       {
 211         z->state->mode = BLOCKS;
 212         break;
 213       }
 214       z->state->mode = DICT4;
 215     case DICT4:
 216       NEEDBYTE
 217       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
 218       z->state->mode = DICT3;
 219     case DICT3:
 220       NEEDBYTE
 221       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
 222       z->state->mode = DICT2;
 223     case DICT2:
 224       NEEDBYTE
 225       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
 226       z->state->mode = DICT1;
 227     case DICT1:
 228       NEEDBYTE
 229       z->state->sub.check.need += (uLong)NEXTBYTE;
 230       z->adler = z->state->sub.check.need;
 231       z->state->mode = DICT0;
 232       return Z_NEED_DICT;
 233     case DICT0:
 234       z->state->mode = BAD;
 235       z->msg = (char*)"need dictionary";
 236       z->state->sub.marker = 0;       /* can try inflateSync */
 237       return Z_STREAM_ERROR;
 238     case BLOCKS:
 239       r = inflate_blocks(z->state->blocks, z, r);
 240       if (r == Z_DATA_ERROR)
 241       {
 242         z->state->mode = BAD;
 243         z->state->sub.marker = 0;       /* can try inflateSync */
 244         break;
 245       }
 246       if (r == Z_OK)
 247         r = f;
 248       if (r != Z_STREAM_END)
 249         return r;
 250       r = f;
 251       inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
 252       if (z->state->nowrap)
 253       {
 254         z->state->mode = DONE;
 255         break;
 256       }
 257       z->state->mode = CHECK4;
 258     case CHECK4:
 259       NEEDBYTE
 260       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
 261       z->state->mode = CHECK3;
 262     case CHECK3:
 263       NEEDBYTE
 264       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
 265       z->state->mode = CHECK2;
 266     case CHECK2:
 267       NEEDBYTE
 268       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
 269       z->state->mode = CHECK1;
 270     case CHECK1:
 271       NEEDBYTE
 272       z->state->sub.check.need += (uLong)NEXTBYTE;
 273
 274       if (z->state->sub.check.was != z->state->sub.check.need)
 275       {
 276         z->state->mode = BAD;
 277         z->msg = (char*)"incorrect data check";
 278         z->state->sub.marker = 5;       /* can't try inflateSync */
 279         break;
 280       }
 281       Tracev((stderr, "inflate: zlib check ok\n"));
 282       z->state->mode = DONE;
 283     case DONE:
 284       return Z_STREAM_END;
 285     case BAD:
 286       return Z_DATA_ERROR;
 287     default:
 288       return Z_STREAM_ERROR;
 289   }
 290 #ifdef NEED_DUMMY_RETURN
 291   return Z_STREAM_ERROR;  /* Some dumb compilers complain without this */
 292 #endif
 293 }
 294
 295
 296 int ZEXPORT inflateSetDictionary(z, dictionary, dictLength)
 297 z_streamp z;
 298 const Bytef *dictionary;
 299 uInt  dictLength;
 300 {
 301   uInt length = dictLength;
 302
 303   if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0)
 304     return Z_STREAM_ERROR;
 305
 306   if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
 307   z->adler = 1L;
 308
 309   if (length >= ((uInt)1<<z->state->wbits))
 310   {
 311     length = (1<<z->state->wbits)-1;
 312     dictionary += dictLength - length;
 313   }
 314   inflate_set_dictionary(z->state->blocks, dictionary, length);
 315   z->state->mode = BLOCKS;
 316   return Z_OK;
 317 }
 318
 319
 320 int ZEXPORT inflateSync(z)
 321 z_streamp z;
 322 {
 323   uInt n;       /* number of bytes to look at */
 324   Bytef *p;     /* pointer to bytes */
 325   uInt m;       /* number of marker bytes found in a row */
 326   uLong r, w;   /* temporaries to save total_in and total_out */
 327
 328   /* set up */
 329   if (z == Z_NULL || z->state == Z_NULL)
 330     return Z_STREAM_ERROR;
 331   if (z->state->mode != BAD)
 332   {
 333     z->state->mode = BAD;
 334     z->state->sub.marker = 0;
 335   }
 336   if ((n = z->avail_in) == 0)
 337     return Z_BUF_ERROR;
 338   p = z->next_in;
 339   m = z->state->sub.marker;
 340
 341   /* search */
 342   while (n && m < 4)
 343   {
 344     static const Byte mark[4] = {0, 0, 0xff, 0xff};
 345     if (*p == mark[m])
 346       m++;
 347     else if (*p)
 348       m = 0;
 349     else
 350       m = 4 - m;
 351     p++, n--;
 352   }
 353
 354   /* restore */
 355   z->total_in += p - z->next_in;
 356   z->next_in = p;
 357   z->avail_in = n;
 358   z->state->sub.marker = m;
 359
 360   /* return no joy or set up to restart on a new block */
 361   if (m != 4)
 362     return Z_DATA_ERROR;
 363   r = z->total_in;  w = z->total_out;
 364   inflateReset(z);
 365   z->total_in = r;  z->total_out = w;
 366   z->state->mode = BLOCKS;
 367   return Z_OK;
 368 }
 369
 370
 371 /* Returns true if inflate is currently at the end of a block generated
 372  * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
 373  * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
 374  * but removes the length bytes of the resulting empty stored block. When
 375  * decompressing, PPP checks that at the end of input packet, inflate is
 376  * waiting for these length bytes.
 377  */
 378 int ZEXPORT inflateSyncPoint(z)
 379 z_streamp z;
 380 {
 381   if (z == Z_NULL || z->state == Z_NULL || z->state->blocks == Z_NULL)
 382     return Z_STREAM_ERROR;
 383   return inflate_blocks_sync_point(z->state->blocks);
 384 }