1 | /* infblock.c -- interpret and process block types to last block |
---|
2 | * Copyright (C) 1995-2002 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 | |
---|
13 | /* simplify the use of the inflate_huft type with some defines */ |
---|
14 | #define exop word.what.Exop |
---|
15 | #define bits word.what.Bits |
---|
16 | |
---|
17 | /* Table for deflate from PKZIP's appnote.txt. */ |
---|
18 | local const uInt border[] = { /* Order of the bit length code lengths */ |
---|
19 | 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; |
---|
20 | |
---|
21 | /* |
---|
22 | Notes beyond the 1.93a appnote.txt: |
---|
23 | |
---|
24 | 1. Distance pointers never point before the beginning of the output |
---|
25 | stream. |
---|
26 | 2. Distance pointers can point back across blocks, up to 32k away. |
---|
27 | 3. There is an implied maximum of 7 bits for the bit length table and |
---|
28 | 15 bits for the actual data. |
---|
29 | 4. If only one code exists, then it is encoded using one bit. (Zero |
---|
30 | would be more efficient, but perhaps a little confusing.) If two |
---|
31 | codes exist, they are coded using one bit each (0 and 1). |
---|
32 | 5. There is no way of sending zero distance codes--a dummy must be |
---|
33 | sent if there are none. (History: a pre 2.0 version of PKZIP would |
---|
34 | store blocks with no distance codes, but this was discovered to be |
---|
35 | too harsh a criterion.) Valid only for 1.93a. 2.04c does allow |
---|
36 | zero distance codes, which is sent as one code of zero bits in |
---|
37 | length. |
---|
38 | 6. There are up to 286 literal/length codes. Code 256 represents the |
---|
39 | end-of-block. Note however that the static length tree defines |
---|
40 | 288 codes just to fill out the Huffman codes. Codes 286 and 287 |
---|
41 | cannot be used though, since there is no length base or extra bits |
---|
42 | defined for them. Similarily, there are up to 30 distance codes. |
---|
43 | However, static trees define 32 codes (all 5 bits) to fill out the |
---|
44 | Huffman codes, but the last two had better not show up in the data. |
---|
45 | 7. Unzip can check dynamic Huffman blocks for complete code sets. |
---|
46 | The exception is that a single code would not be complete (see #4). |
---|
47 | 8. The five bits following the block type is really the number of |
---|
48 | literal codes sent minus 257. |
---|
49 | 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits |
---|
50 | (1+6+6). Therefore, to output three times the length, you output |
---|
51 | three codes (1+1+1), whereas to output four times the same length, |
---|
52 | you only need two codes (1+3). Hmm. |
---|
53 | 10. In the tree reconstruction algorithm, Code = Code + Increment |
---|
54 | only if BitLength(i) is not zero. (Pretty obvious.) |
---|
55 | 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19) |
---|
56 | 12. Note: length code 284 can represent 227-258, but length code 285 |
---|
57 | really is 258. The last length deserves its own, short code |
---|
58 | since it gets used a lot in very redundant files. The length |
---|
59 | 258 is special since 258 - 3 (the min match length) is 255. |
---|
60 | 13. The literal/length and distance code bit lengths are read as a |
---|
61 | single stream of lengths. It is possible (and advantageous) for |
---|
62 | a repeat code (16, 17, or 18) to go across the boundary between |
---|
63 | the two sets of lengths. |
---|
64 | */ |
---|
65 | |
---|
66 | |
---|
67 | local void inflate_blocks_reset( /* s, z, c) */ |
---|
68 | inflate_blocks_statef *s, |
---|
69 | z_streamp z, |
---|
70 | uLongf *c ) |
---|
71 | { |
---|
72 | if (c != Z_NULL) |
---|
73 | *c = s->check; |
---|
74 | if (s->mode == BTREE || s->mode == DTREE) |
---|
75 | ZFREE(z, s->sub.trees.blens); |
---|
76 | if (s->mode == CODES) |
---|
77 | inflate_codes_free(s->sub.decode.codes, z); |
---|
78 | s->mode = TYPE; |
---|
79 | s->bitk = 0; |
---|
80 | s->bitb = 0; |
---|
81 | s->read = s->write = s->window; |
---|
82 | if (s->checkfn != Z_NULL) |
---|
83 | z->adler = s->check = (*s->checkfn)(0L, (const Bytef *)Z_NULL, 0); |
---|
84 | Tracev((stderr, "inflate: blocks reset\n")); |
---|
85 | } |
---|
86 | |
---|
87 | |
---|
88 | local inflate_blocks_statef *inflate_blocks_new( /* z, c, w) */ |
---|
89 | z_streamp z, |
---|
90 | check_func c, |
---|
91 | uInt w ) |
---|
92 | { |
---|
93 | inflate_blocks_statef *s; |
---|
94 | |
---|
95 | if ((s = (inflate_blocks_statef *)ZALLOC |
---|
96 | (z,1,sizeof(struct inflate_blocks_state))) == Z_NULL) |
---|
97 | return s; |
---|
98 | if ((s->hufts = |
---|
99 | (inflate_huft *)ZALLOC(z, sizeof(inflate_huft), MANY)) == Z_NULL) |
---|
100 | { |
---|
101 | ZFREE(z, s); |
---|
102 | return Z_NULL; |
---|
103 | } |
---|
104 | if ((s->window = (Bytef *)ZALLOC(z, 1, w)) == Z_NULL) |
---|
105 | { |
---|
106 | ZFREE(z, s->hufts); |
---|
107 | ZFREE(z, s); |
---|
108 | return Z_NULL; |
---|
109 | } |
---|
110 | s->end = s->window + w; |
---|
111 | s->checkfn = c; |
---|
112 | s->mode = TYPE; |
---|
113 | Tracev((stderr, "inflate: blocks allocated\n")); |
---|
114 | inflate_blocks_reset(s, z, Z_NULL); |
---|
115 | return s; |
---|
116 | } |
---|
117 | |
---|
118 | |
---|
119 | local int inflate_blocks( /* s, z, r) */ |
---|
120 | inflate_blocks_statef *s, |
---|
121 | z_streamp z, |
---|
122 | int r ) |
---|
123 | { |
---|
124 | uInt t; /* temporary storage */ |
---|
125 | uLong b; /* bit buffer */ |
---|
126 | uInt k; /* bits in bit buffer */ |
---|
127 | Bytef *p; /* input data pointer */ |
---|
128 | uInt n; /* bytes available there */ |
---|
129 | Bytef *q; /* output window write pointer */ |
---|
130 | uInt m; /* bytes to end of window or read pointer */ |
---|
131 | |
---|
132 | /* copy input/output information to locals (UPDATE macro restores) */ |
---|
133 | LOAD |
---|
134 | |
---|
135 | /* process input based on current state */ |
---|
136 | while (1) switch (s->mode) |
---|
137 | { |
---|
138 | case TYPE: |
---|
139 | NEEDBITS(3) |
---|
140 | t = (uInt)b & 7; |
---|
141 | s->last = t & 1; |
---|
142 | switch (t >> 1) |
---|
143 | { |
---|
144 | case 0: /* stored */ |
---|
145 | Tracev((stderr, "inflate: stored block%s\n", |
---|
146 | s->last ? " (last)" : "")); |
---|
147 | DUMPBITS(3) |
---|
148 | t = k & 7; /* go to byte boundary */ |
---|
149 | DUMPBITS(t) |
---|
150 | s->mode = LENS; /* get length of stored block */ |
---|
151 | break; |
---|
152 | case 1: /* fixed */ |
---|
153 | Tracev((stderr, "inflate: fixed codes block%s\n", |
---|
154 | s->last ? " (last)" : "")); |
---|
155 | { |
---|
156 | uInt bl, bd; |
---|
157 | inflate_huft *tl, *td; |
---|
158 | |
---|
159 | inflate_trees_fixed(&bl, &bd, (const inflate_huft**)&tl, |
---|
160 | (const inflate_huft**)&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 | r = t; |
---|
253 | if (r == Z_DATA_ERROR) |
---|
254 | { |
---|
255 | ZFREE(z, s->sub.trees.blens); |
---|
256 | s->mode = BAD; |
---|
257 | } |
---|
258 | LEAVE |
---|
259 | } |
---|
260 | s->sub.trees.index = 0; |
---|
261 | Tracev((stderr, "inflate: bits tree ok\n")); |
---|
262 | s->mode = DTREE; |
---|
263 | case DTREE: |
---|
264 | while (t = s->sub.trees.table, |
---|
265 | s->sub.trees.index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f)) |
---|
266 | { |
---|
267 | inflate_huft *h; |
---|
268 | uInt i, j, c; |
---|
269 | |
---|
270 | t = s->sub.trees.bb; |
---|
271 | NEEDBITS(t) |
---|
272 | h = s->sub.trees.tb + ((uInt)b & inflate_mask[t]); |
---|
273 | t = h->bits; |
---|
274 | c = h->base; |
---|
275 | if (c < 16) |
---|
276 | { |
---|
277 | DUMPBITS(t) |
---|
278 | s->sub.trees.blens[s->sub.trees.index++] = c; |
---|
279 | } |
---|
280 | else /* c == 16..18 */ |
---|
281 | { |
---|
282 | i = c == 18 ? 7 : c - 14; |
---|
283 | j = c == 18 ? 11 : 3; |
---|
284 | NEEDBITS(t + i) |
---|
285 | DUMPBITS(t) |
---|
286 | j += (uInt)b & inflate_mask[i]; |
---|
287 | DUMPBITS(i) |
---|
288 | i = s->sub.trees.index; |
---|
289 | t = s->sub.trees.table; |
---|
290 | if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) || |
---|
291 | (c == 16 && i < 1)) |
---|
292 | { |
---|
293 | ZFREE(z, s->sub.trees.blens); |
---|
294 | s->mode = BAD; |
---|
295 | z->msg = (char*)"invalid bit length repeat"; |
---|
296 | r = Z_DATA_ERROR; |
---|
297 | LEAVE |
---|
298 | } |
---|
299 | c = c == 16 ? s->sub.trees.blens[i - 1] : 0; |
---|
300 | do { |
---|
301 | s->sub.trees.blens[i++] = c; |
---|
302 | } while (--j); |
---|
303 | s->sub.trees.index = i; |
---|
304 | } |
---|
305 | } |
---|
306 | s->sub.trees.tb = Z_NULL; |
---|
307 | { |
---|
308 | uInt bl, bd; |
---|
309 | inflate_huft *tl, *td; |
---|
310 | inflate_codes_statef *c; |
---|
311 | |
---|
312 | bl = 9; /* must be <= 9 for lookahead assumptions */ |
---|
313 | bd = 6; /* must be <= 9 for lookahead assumptions */ |
---|
314 | t = s->sub.trees.table; |
---|
315 | t = inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f), |
---|
316 | s->sub.trees.blens, &bl, &bd, &tl, &td, |
---|
317 | s->hufts, z); |
---|
318 | if (t != Z_OK) |
---|
319 | { |
---|
320 | if (t == (uInt)Z_DATA_ERROR) |
---|
321 | { |
---|
322 | ZFREE(z, s->sub.trees.blens); |
---|
323 | s->mode = BAD; |
---|
324 | } |
---|
325 | r = t; |
---|
326 | LEAVE |
---|
327 | } |
---|
328 | Tracev((stderr, "inflate: trees ok\n")); |
---|
329 | if ((c = inflate_codes_new(bl, bd, tl, td, z)) == Z_NULL) |
---|
330 | { |
---|
331 | r = Z_MEM_ERROR; |
---|
332 | LEAVE |
---|
333 | } |
---|
334 | s->sub.decode.codes = c; |
---|
335 | } |
---|
336 | ZFREE(z, s->sub.trees.blens); |
---|
337 | s->mode = CODES; |
---|
338 | case CODES: |
---|
339 | UPDATE |
---|
340 | if ((r = inflate_codes(s, z, r)) != Z_STREAM_END) |
---|
341 | return inflate_flush(s, z, r); |
---|
342 | r = Z_OK; |
---|
343 | inflate_codes_free(s->sub.decode.codes, z); |
---|
344 | LOAD |
---|
345 | Tracev((stderr, "inflate: codes end, %lu total out\n", |
---|
346 | z->total_out + (q >= s->read ? q - s->read : |
---|
347 | (s->end - s->read) + (q - s->window)))); |
---|
348 | if (!s->last) |
---|
349 | { |
---|
350 | s->mode = TYPE; |
---|
351 | break; |
---|
352 | } |
---|
353 | s->mode = DRY; |
---|
354 | case DRY: |
---|
355 | FLUSH |
---|
356 | if (s->read != s->write) |
---|
357 | LEAVE |
---|
358 | s->mode = DONE; |
---|
359 | case DONE: |
---|
360 | r = Z_STREAM_END; |
---|
361 | LEAVE |
---|
362 | case BAD: |
---|
363 | r = Z_DATA_ERROR; |
---|
364 | LEAVE |
---|
365 | default: |
---|
366 | r = Z_STREAM_ERROR; |
---|
367 | LEAVE |
---|
368 | } |
---|
369 | #ifdef NEED_DUMMY_RETURN |
---|
370 | return 0; |
---|
371 | #endif |
---|
372 | } |
---|
373 | |
---|
374 | |
---|
375 | local int inflate_blocks_free( /* s, z) */ |
---|
376 | inflate_blocks_statef *s, |
---|
377 | z_streamp z ) |
---|
378 | { |
---|
379 | inflate_blocks_reset(s, z, Z_NULL); |
---|
380 | ZFREE(z, s->window); |
---|
381 | ZFREE(z, s->hufts); |
---|
382 | ZFREE(z, s); |
---|
383 | Tracev((stderr, "inflate: blocks freed\n")); |
---|
384 | return Z_OK; |
---|
385 | } |
---|
386 | |
---|
387 | |
---|