|
0
|
1 /* infblock.c -- interpret and process block types to last block
|
|
|
2 * Copyright (C) 1995-1998 Mark Adler
|
|
|
3 * For conditions of distribution and use, see copyright notice in zlib.h
|
|
|
4 */
|
|
|
5
|
|
|
6 #include "zutil.h"
|
|
|
7 #include "infblock.h"
|
|
|
8 #include "inftrees.h"
|
|
|
9 #include "infcodes.h"
|
|
|
10 #include "infutil.h"
|
|
|
11
|
|
|
12 struct inflate_codes_state {int dummy;}; /* for buggy compilers */
|
|
|
13
|
|
|
14 /* simplify the use of the inflate_huft type with some defines */
|
|
|
15 #define exop word.what.Exop
|
|
|
16 #define bits word.what.Bits
|
|
|
17
|
|
|
18 /* Table for deflate from PKZIP's appnote.txt. */
|
|
|
19 local const uInt border[] = { /* Order of the bit length code lengths */
|
|
|
20 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
|
|
|
21
|
|
|
22 /*
|
|
|
23 Notes beyond the 1.93a appnote.txt:
|
|
|
24
|
|
|
25 1. Distance pointers never point before the beginning of the output
|
|
|
26 stream.
|
|
|
27 2. Distance pointers can point back across blocks, up to 32k away.
|
|
|
28 3. There is an implied maximum of 7 bits for the bit length table and
|
|
|
29 15 bits for the actual data.
|
|
|
30 4. If only one code exists, then it is encoded using one bit. (Zero
|
|
|
31 would be more efficient, but perhaps a little confusing.) If two
|
|
|
32 codes exist, they are coded using one bit each (0 and 1).
|
|
|
33 5. There is no way of sending zero distance codes--a dummy must be
|
|
|
34 sent if there are none. (History: a pre 2.0 version of PKZIP would
|
|
|
35 store blocks with no distance codes, but this was discovered to be
|
|
|
36 too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
|
|
|
37 zero distance codes, which is sent as one code of zero bits in
|
|
|
38 length.
|
|
|
39 6. There are up to 286 literal/length codes. Code 256 represents the
|
|
|
40 end-of-block. Note however that the static length tree defines
|
|
|
41 288 codes just to fill out the Huffman codes. Codes 286 and 287
|
|
|
42 cannot be used though, since there is no length base or extra bits
|
|
|
43 defined for them. Similarily, there are up to 30 distance codes.
|
|
|
44 However, static trees define 32 codes (all 5 bits) to fill out the
|
|
|
45 Huffman codes, but the last two had better not show up in the data.
|
|
|
46 7. Unzip can check dynamic Huffman blocks for complete code sets.
|
|
|
47 The exception is that a single code would not be complete (see #4).
|
|
|
48 8. The five bits following the block type is really the number of
|
|
|
49 literal codes sent minus 257.
|
|
|
50 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
|
|
|
51 (1+6+6). Therefore, to output three times the length, you output
|
|
|
52 three codes (1+1+1), whereas to output four times the same length,
|
|
|
53 you only need two codes (1+3). Hmm.
|
|
|
54 10. In the tree reconstruction algorithm, Code = Code + Increment
|
|
|
55 only if BitLength(i) is not zero. (Pretty obvious.)
|
|
|
56 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
|
|
|
57 12. Note: length code 284 can represent 227-258, but length code 285
|
|
|
58 really is 258. The last length deserves its own, short code
|
|
|
59 since it gets used a lot in very redundant files. The length
|
|
|
60 258 is special since 258 - 3 (the min match length) is 255.
|
|
|
61 13. The literal/length and distance code bit lengths are read as a
|
|
|
62 single stream of lengths. It is possible (and advantageous) for
|
|
|
63 a repeat code (16, 17, or 18) to go across the boundary between
|
|
|
64 the two sets of lengths.
|
|
|
65 */
|
|
|
66
|
|
|
67
|
|
|
68 void inflate_blocks_reset(s, z, c)
|
|
|
69 inflate_blocks_statef *s;
|
|
|
70 z_streamp z;
|
|
|
71 uLongf *c;
|
|
|
72 {
|
|
|
73 if (c != Z_NULL)
|
|
|
74 *c = s->check;
|
|
|
75 if (s->mode == BTREE || s->mode == DTREE)
|
|
|
76 ZFREE(z, s->sub.trees.blens);
|
|
|
77 if (s->mode == CODES)
|
|
|
78 inflate_codes_free(s->sub.decode.codes, z);
|
|
|
79 s->mode = TYPE;
|
|
|
80 s->bitk = 0;
|
|
|
81 s->bitb = 0;
|
|
|
82 s->read = s->write = s->window;
|
|
|
83 if (s->checkfn != Z_NULL)
|
|
|
84 z->adler = s->check = (*s->checkfn)(0L, (const Bytef *)Z_NULL, 0);
|
|
|
85 Tracev((stderr, "inflate: blocks reset\n"));
|
|
|
86 }
|
|
|
87
|
|
|
88
|
|
|
89 inflate_blocks_statef *inflate_blocks_new(z, c, w)
|
|
|
90 z_streamp z;
|
|
|
91 check_func c;
|
|
|
92 uInt w;
|
|
|
93 {
|
|
|
94 inflate_blocks_statef *s;
|
|
|
95
|
|
|
96 if ((s = (inflate_blocks_statef *)ZALLOC
|
|
|
97 (z,1,sizeof(struct inflate_blocks_state))) == Z_NULL)
|
|
|
98 return s;
|
|
|
99 if ((s->hufts =
|
|
|
100 (inflate_huft *)ZALLOC(z, sizeof(inflate_huft), MANY)) == Z_NULL)
|
|
|
101 {
|
|
|
102 ZFREE(z, s);
|
|
|
103 return Z_NULL;
|
|
|
104 }
|
|
|
105 if ((s->window = (Bytef *)ZALLOC(z, 1, w)) == Z_NULL)
|
|
|
106 {
|
|
|
107 ZFREE(z, s->hufts);
|
|
|
108 ZFREE(z, s);
|
|
|
109 return Z_NULL;
|
|
|
110 }
|
|
|
111 s->end = s->window + w;
|
|
|
112 s->checkfn = c;
|
|
|
113 s->mode = TYPE;
|
|
|
114 Tracev((stderr, "inflate: blocks allocated\n"));
|
|
|
115 inflate_blocks_reset(s, z, Z_NULL);
|
|
|
116 return s;
|
|
|
117 }
|
|
|
118
|
|
|
119
|
|
|
120 int inflate_blocks(s, z, r)
|
|
|
121 inflate_blocks_statef *s;
|
|
|
122 z_streamp z;
|
|
|
123 int r;
|
|
|
124 {
|
|
|
125 uInt t; /* temporary storage */
|
|
|
126 uLong b; /* bit buffer */
|
|
|
127 uInt k; /* bits in bit buffer */
|
|
|
128 Bytef *p; /* input data pointer */
|
|
|
129 uInt n; /* bytes available there */
|
|
|
130 Bytef *q; /* output window write pointer */
|
|
|
131 uInt m; /* bytes to end of window or read pointer */
|
|
|
132
|
|
|
133 /* copy input/output information to locals (UPDATE macro restores) */
|
|
|
134 LOAD
|
|
|
135
|
|
|
136 /* process input based on current state */
|
|
|
137 while (1) switch (s->mode)
|
|
|
138 {
|
|
|
139 case TYPE:
|
|
|
140 NEEDBITS(3)
|
|
|
141 t = (uInt)b & 7;
|
|
|
142 s->last = t & 1;
|
|
|
143 switch (t >> 1)
|
|
|
144 {
|
|
|
145 case 0: /* stored */
|
|
|
146 Tracev((stderr, "inflate: stored block%s\n",
|
|
|
147 s->last ? " (last)" : ""));
|
|
|
148 DUMPBITS(3)
|
|
|
149 t = k & 7; /* go to byte boundary */
|
|
|
150 DUMPBITS(t)
|
|
|
151 s->mode = LENS; /* get length of stored block */
|
|
|
152 break;
|
|
|
153 case 1: /* fixed */
|
|
|
154 Tracev((stderr, "inflate: fixed codes block%s\n",
|
|
|
155 s->last ? " (last)" : ""));
|
|
|
156 {
|
|
|
157 uInt bl, bd;
|
|
|
158 inflate_huft *tl, *td;
|
|
|
159
|
|
|
160 inflate_trees_fixed(&bl, &bd, &tl, &td, z);
|
|
|
161 s->sub.decode.codes = inflate_codes_new(bl, bd, tl, td, z);
|
|
|
162 if (s->sub.decode.codes == Z_NULL)
|
|
|
163 {
|
|
|
164 r = Z_MEM_ERROR;
|
|
|
165 LEAVE
|
|
|
166 }
|
|
|
167 }
|
|
|
168 DUMPBITS(3)
|
|
|
169 s->mode = CODES;
|
|
|
170 break;
|
|
|
171 case 2: /* dynamic */
|
|
|
172 Tracev((stderr, "inflate: dynamic codes block%s\n",
|
|
|
173 s->last ? " (last)" : ""));
|
|
|
174 DUMPBITS(3)
|
|
|
175 s->mode = TABLE;
|
|
|
176 break;
|
|
|
177 case 3: /* illegal */
|
|
|
178 DUMPBITS(3)
|
|
|
179 s->mode = BAD;
|
|
|
180 z->msg = (char*)"invalid block type";
|
|
|
181 r = Z_DATA_ERROR;
|
|
|
182 LEAVE
|
|
|
183 }
|
|
|
184 break;
|
|
|
185 case LENS:
|
|
|
186 NEEDBITS(32)
|
|
|
187 if ((((~b) >> 16) & 0xffff) != (b & 0xffff))
|
|
|
188 {
|
|
|
189 s->mode = BAD;
|
|
|
190 z->msg = (char*)"invalid stored block lengths";
|
|
|
191 r = Z_DATA_ERROR;
|
|
|
192 LEAVE
|
|
|
193 }
|
|
|
194 s->sub.left = (uInt)b & 0xffff;
|
|
|
195 b = k = 0; /* dump bits */
|
|
|
196 Tracev((stderr, "inflate: stored length %u\n", s->sub.left));
|
|
|
197 s->mode = s->sub.left ? STORED : (s->last ? DRY : TYPE);
|
|
|
198 break;
|
|
|
199 case STORED:
|
|
|
200 if (n == 0)
|
|
|
201 LEAVE
|
|
|
202 NEEDOUT
|
|
|
203 t = s->sub.left;
|
|
|
204 if (t > n) t = n;
|
|
|
205 if (t > m) t = m;
|
|
|
206 zmemcpy(q, p, t);
|
|
|
207 p += t; n -= t;
|
|
|
208 q += t; m -= t;
|
|
|
209 if ((s->sub.left -= t) != 0)
|
|
|
210 break;
|
|
|
211 Tracev((stderr, "inflate: stored end, %lu total out\n",
|
|
|
212 z->total_out + (q >= s->read ? q - s->read :
|
|
|
213 (s->end - s->read) + (q - s->window))));
|
|
|
214 s->mode = s->last ? DRY : TYPE;
|
|
|
215 break;
|
|
|
216 case TABLE:
|
|
|
217 NEEDBITS(14)
|
|
|
218 s->sub.trees.table = t = (uInt)b & 0x3fff;
|
|
|
219 #ifndef PKZIP_BUG_WORKAROUND
|
|
|
220 if ((t & 0x1f) > 29 || ((t >> 5) & 0x1f) > 29)
|
|
|
221 {
|
|
|
222 s->mode = BAD;
|
|
|
223 z->msg = (char*)"too many length or distance symbols";
|
|
|
224 r = Z_DATA_ERROR;
|
|
|
225 LEAVE
|
|
|
226 }
|
|
|
227 #endif
|
|
|
228 t = 258 + (t & 0x1f) + ((t >> 5) & 0x1f);
|
|
|
229 if ((s->sub.trees.blens = (uIntf*)ZALLOC(z, t, sizeof(uInt))) == Z_NULL)
|
|
|
230 {
|
|
|
231 r = Z_MEM_ERROR;
|
|
|
232 LEAVE
|
|
|
233 }
|
|
|
234 DUMPBITS(14)
|
|
|
235 s->sub.trees.index = 0;
|
|
|
236 Tracev((stderr, "inflate: table sizes ok\n"));
|
|
|
237 s->mode = BTREE;
|
|
|
238 case BTREE:
|
|
|
239 while (s->sub.trees.index < 4 + (s->sub.trees.table >> 10))
|
|
|
240 {
|
|
|
241 NEEDBITS(3)
|
|
|
242 s->sub.trees.blens[border[s->sub.trees.index++]] = (uInt)b & 7;
|
|
|
243 DUMPBITS(3)
|
|
|
244 }
|
|
|
245 while (s->sub.trees.index < 19)
|
|
|
246 s->sub.trees.blens[border[s->sub.trees.index++]] = 0;
|
|
|
247 s->sub.trees.bb = 7;
|
|
|
248 t = inflate_trees_bits(s->sub.trees.blens, &s->sub.trees.bb,
|
|
|
249 &s->sub.trees.tb, s->hufts, z);
|
|
|
250 if (t != Z_OK)
|
|
|
251 {
|
|
|
252 ZFREE(z, s->sub.trees.blens);
|
|
|
253 r = t;
|
|
|
254 if (r == Z_DATA_ERROR)
|
|
|
255 s->mode = BAD;
|
|
|
256 LEAVE
|
|
|
257 }
|
|
|
258 s->sub.trees.index = 0;
|
|
|
259 Tracev((stderr, "inflate: bits tree ok\n"));
|
|
|
260 s->mode = DTREE;
|
|
|
261 case DTREE:
|
|
|
262 while (t = s->sub.trees.table,
|
|
|
263 s->sub.trees.index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f))
|
|
|
264 {
|
|
|
265 inflate_huft *h;
|
|
|
266 uInt i, j, c;
|
|
|
267
|
|
|
268 t = s->sub.trees.bb;
|
|
|
269 NEEDBITS(t)
|
|
|
270 h = s->sub.trees.tb + ((uInt)b & inflate_mask[t]);
|
|
|
271 t = h->bits;
|
|
|
272 c = h->base;
|
|
|
273 if (c < 16)
|
|
|
274 {
|
|
|
275 DUMPBITS(t)
|
|
|
276 s->sub.trees.blens[s->sub.trees.index++] = c;
|
|
|
277 }
|
|
|
278 else /* c == 16..18 */
|
|
|
279 {
|
|
|
280 i = c == 18 ? 7 : c - 14;
|
|
|
281 j = c == 18 ? 11 : 3;
|
|
|
282 NEEDBITS(t + i)
|
|
|
283 DUMPBITS(t)
|
|
|
284 j += (uInt)b & inflate_mask[i];
|
|
|
285 DUMPBITS(i)
|
|
|
286 i = s->sub.trees.index;
|
|
|
287 t = s->sub.trees.table;
|
|
|
288 if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) ||
|
|
|
289 (c == 16 && i < 1))
|
|
|
290 {
|
|
|
291 ZFREE(z, s->sub.trees.blens);
|
|
|
292 s->mode = BAD;
|
|
|
293 z->msg = (char*)"invalid bit length repeat";
|
|
|
294 r = Z_DATA_ERROR;
|
|
|
295 LEAVE
|
|
|
296 }
|
|
|
297 c = c == 16 ? s->sub.trees.blens[i - 1] : 0;
|
|
|
298 do {
|
|
|
299 s->sub.trees.blens[i++] = c;
|
|
|
300 } while (--j);
|
|
|
301 s->sub.trees.index = i;
|
|
|
302 }
|
|
|
303 }
|
|
|
304 s->sub.trees.tb = Z_NULL;
|
|
|
305 {
|
|
|
306 uInt bl, bd;
|
|
|
307 inflate_huft *tl, *td;
|
|
|
308 inflate_codes_statef *c;
|
|
|
309
|
|
|
310 bl = 9; /* must be <= 9 for lookahead assumptions */
|
|
|
311 bd = 6; /* must be <= 9 for lookahead assumptions */
|
|
|
312 t = s->sub.trees.table;
|
|
|
313 t = inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f),
|
|
|
314 s->sub.trees.blens, &bl, &bd, &tl, &td,
|
|
|
315 s->hufts, z);
|
|
|
316 ZFREE(z, s->sub.trees.blens);
|
|
|
317 if (t != Z_OK)
|
|
|
318 {
|
|
|
319 if (t == (uInt)Z_DATA_ERROR)
|
|
|
320 s->mode = BAD;
|
|
|
321 r = t;
|
|
|
322 LEAVE
|
|
|
323 }
|
|
|
324 Tracev((stderr, "inflate: trees ok\n"));
|
|
|
325 if ((c = inflate_codes_new(bl, bd, tl, td, z)) == Z_NULL)
|
|
|
326 {
|
|
|
327 r = Z_MEM_ERROR;
|
|
|
328 LEAVE
|
|
|
329 }
|
|
|
330 s->sub.decode.codes = c;
|
|
|
331 }
|
|
|
332 s->mode = CODES;
|
|
|
333 case CODES:
|
|
|
334 UPDATE
|
|
|
335 if ((r = inflate_codes(s, z, r)) != Z_STREAM_END)
|
|
|
336 return inflate_flush(s, z, r);
|
|
|
337 r = Z_OK;
|
|
|
338 inflate_codes_free(s->sub.decode.codes, z);
|
|
|
339 LOAD
|
|
|
340 Tracev((stderr, "inflate: codes end, %lu total out\n",
|
|
|
341 z->total_out + (q >= s->read ? q - s->read :
|
|
|
342 (s->end - s->read) + (q - s->window))));
|
|
|
343 if (!s->last)
|
|
|
344 {
|
|
|
345 s->mode = TYPE;
|
|
|
346 break;
|
|
|
347 }
|
|
|
348 s->mode = DRY;
|
|
|
349 case DRY:
|
|
|
350 FLUSH
|
|
|
351 if (s->read != s->write)
|
|
|
352 LEAVE
|
|
|
353 s->mode = DONE;
|
|
|
354 case DONE:
|
|
|
355 r = Z_STREAM_END;
|
|
|
356 LEAVE
|
|
|
357 case BAD:
|
|
|
358 r = Z_DATA_ERROR;
|
|
|
359 LEAVE
|
|
|
360 default:
|
|
|
361 r = Z_STREAM_ERROR;
|
|
|
362 LEAVE
|
|
|
363 }
|
|
|
364 }
|
|
|
365
|
|
|
366
|
|
|
367 int inflate_blocks_free(s, z)
|
|
|
368 inflate_blocks_statef *s;
|
|
|
369 z_streamp z;
|
|
|
370 {
|
|
|
371 inflate_blocks_reset(s, z, Z_NULL);
|
|
|
372 ZFREE(z, s->window);
|
|
|
373 ZFREE(z, s->hufts);
|
|
|
374 ZFREE(z, s);
|
|
|
375 Tracev((stderr, "inflate: blocks freed\n"));
|
|
|
376 return Z_OK;
|
|
|
377 }
|
|
|
378
|
|
|
379
|
|
|
380 void inflate_set_dictionary(s, d, n)
|
|
|
381 inflate_blocks_statef *s;
|
|
|
382 const Bytef *d;
|
|
|
383 uInt n;
|
|
|
384 {
|
|
|
385 zmemcpy(s->window, d, n);
|
|
|
386 s->read = s->write = s->window + n;
|
|
|
387 }
|
|
|
388
|
|
|
389
|
|
|
390 /* Returns true if inflate is currently at the end of a block generated
|
|
|
391 * by Z_SYNC_FLUSH or Z_FULL_FLUSH.
|
|
|
392 * IN assertion: s != Z_NULL
|
|
|
393 */
|
|
|
394 int inflate_blocks_sync_point(s)
|
|
|
395 inflate_blocks_statef *s;
|
|
|
396 {
|
|
|
397 return s->mode == LENS;
|
|
|
398 }
|
