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-rw-r--r--lib/zlib_inflate/infblock.c365
1 files changed, 0 insertions, 365 deletions
diff --git a/lib/zlib_inflate/infblock.c b/lib/zlib_inflate/infblock.c
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--- a/lib/zlib_inflate/infblock.c
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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 <linux/zutil.h>
7#include "infblock.h"
8#include "inftrees.h"
9#include "infcodes.h"
10#include "infutil.h"
11
12struct inflate_codes_state;
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. */
19static 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
68void zlib_inflate_blocks_reset(
69 inflate_blocks_statef *s,
70 z_streamp z,
71 uLong *c
72)
73{
74 if (c != NULL)
75 *c = s->check;
76 if (s->mode == CODES)
77 zlib_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 != NULL)
83 z->adler = s->check = (*s->checkfn)(0L, NULL, 0);
84}
85
86inflate_blocks_statef *zlib_inflate_blocks_new(
87 z_streamp z,
88 check_func c,
89 uInt w
90)
91{
92 inflate_blocks_statef *s;
93
94 s = &WS(z)->working_blocks_state;
95 s->hufts = WS(z)->working_hufts;
96 s->window = WS(z)->working_window;
97 s->end = s->window + w;
98 s->checkfn = c;
99 s->mode = TYPE;
100 zlib_inflate_blocks_reset(s, z, NULL);
101 return s;
102}
103
104
105int zlib_inflate_blocks(
106 inflate_blocks_statef *s,
107 z_streamp z,
108 int r
109)
110{
111 uInt t; /* temporary storage */
112 uLong b; /* bit buffer */
113 uInt k; /* bits in bit buffer */
114 Byte *p; /* input data pointer */
115 uInt n; /* bytes available there */
116 Byte *q; /* output window write pointer */
117 uInt m; /* bytes to end of window or read pointer */
118
119 /* copy input/output information to locals (UPDATE macro restores) */
120 LOAD
121
122 /* process input based on current state */
123 while (1) switch (s->mode)
124 {
125 case TYPE:
126 NEEDBITS(3)
127 t = (uInt)b & 7;
128 s->last = t & 1;
129 switch (t >> 1)
130 {
131 case 0: /* stored */
132 DUMPBITS(3)
133 t = k & 7; /* go to byte boundary */
134 DUMPBITS(t)
135 s->mode = LENS; /* get length of stored block */
136 break;
137 case 1: /* fixed */
138 {
139 uInt bl, bd;
140 inflate_huft *tl, *td;
141
142 zlib_inflate_trees_fixed(&bl, &bd, &tl, &td, s->hufts, z);
143 s->sub.decode.codes = zlib_inflate_codes_new(bl, bd, tl, td, z);
144 if (s->sub.decode.codes == NULL)
145 {
146 r = Z_MEM_ERROR;
147 LEAVE
148 }
149 }
150 DUMPBITS(3)
151 s->mode = CODES;
152 break;
153 case 2: /* dynamic */
154 DUMPBITS(3)
155 s->mode = TABLE;
156 break;
157 case 3: /* illegal */
158 DUMPBITS(3)
159 s->mode = B_BAD;
160 z->msg = (char*)"invalid block type";
161 r = Z_DATA_ERROR;
162 LEAVE
163 }
164 break;
165 case LENS:
166 NEEDBITS(32)
167 if ((((~b) >> 16) & 0xffff) != (b & 0xffff))
168 {
169 s->mode = B_BAD;
170 z->msg = (char*)"invalid stored block lengths";
171 r = Z_DATA_ERROR;
172 LEAVE
173 }
174 s->sub.left = (uInt)b & 0xffff;
175 b = k = 0; /* dump bits */
176 s->mode = s->sub.left ? STORED : (s->last ? DRY : TYPE);
177 break;
178 case STORED:
179 if (n == 0)
180 LEAVE
181 NEEDOUT
182 t = s->sub.left;
183 if (t > n) t = n;
184 if (t > m) t = m;
185 memcpy(q, p, t);
186 p += t; n -= t;
187 q += t; m -= t;
188 if ((s->sub.left -= t) != 0)
189 break;
190 s->mode = s->last ? DRY : TYPE;
191 break;
192 case TABLE:
193 NEEDBITS(14)
194 s->sub.trees.table = t = (uInt)b & 0x3fff;
195#ifndef PKZIP_BUG_WORKAROUND
196 if ((t & 0x1f) > 29 || ((t >> 5) & 0x1f) > 29)
197 {
198 s->mode = B_BAD;
199 z->msg = (char*)"too many length or distance symbols";
200 r = Z_DATA_ERROR;
201 LEAVE
202 }
203#endif
204 {
205 s->sub.trees.blens = WS(z)->working_blens;
206 }
207 DUMPBITS(14)
208 s->sub.trees.index = 0;
209 s->mode = BTREE;
210 case BTREE:
211 while (s->sub.trees.index < 4 + (s->sub.trees.table >> 10))
212 {
213 NEEDBITS(3)
214 s->sub.trees.blens[border[s->sub.trees.index++]] = (uInt)b & 7;
215 DUMPBITS(3)
216 }
217 while (s->sub.trees.index < 19)
218 s->sub.trees.blens[border[s->sub.trees.index++]] = 0;
219 s->sub.trees.bb = 7;
220 t = zlib_inflate_trees_bits(s->sub.trees.blens, &s->sub.trees.bb,
221 &s->sub.trees.tb, s->hufts, z);
222 if (t != Z_OK)
223 {
224 r = t;
225 if (r == Z_DATA_ERROR)
226 s->mode = B_BAD;
227 LEAVE
228 }
229 s->sub.trees.index = 0;
230 s->mode = DTREE;
231 case DTREE:
232 while (t = s->sub.trees.table,
233 s->sub.trees.index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f))
234 {
235 inflate_huft *h;
236 uInt i, j, c;
237
238 t = s->sub.trees.bb;
239 NEEDBITS(t)
240 h = s->sub.trees.tb + ((uInt)b & zlib_inflate_mask[t]);
241 t = h->bits;
242 c = h->base;
243 if (c < 16)
244 {
245 DUMPBITS(t)
246 s->sub.trees.blens[s->sub.trees.index++] = c;
247 }
248 else /* c == 16..18 */
249 {
250 i = c == 18 ? 7 : c - 14;
251 j = c == 18 ? 11 : 3;
252 NEEDBITS(t + i)
253 DUMPBITS(t)
254 j += (uInt)b & zlib_inflate_mask[i];
255 DUMPBITS(i)
256 i = s->sub.trees.index;
257 t = s->sub.trees.table;
258 if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) ||
259 (c == 16 && i < 1))
260 {
261 s->mode = B_BAD;
262 z->msg = (char*)"invalid bit length repeat";
263 r = Z_DATA_ERROR;
264 LEAVE
265 }
266 c = c == 16 ? s->sub.trees.blens[i - 1] : 0;
267 do {
268 s->sub.trees.blens[i++] = c;
269 } while (--j);
270 s->sub.trees.index = i;
271 }
272 }
273 s->sub.trees.tb = NULL;
274 {
275 uInt bl, bd;
276 inflate_huft *tl, *td;
277 inflate_codes_statef *c;
278
279 bl = 9; /* must be <= 9 for lookahead assumptions */
280 bd = 6; /* must be <= 9 for lookahead assumptions */
281 t = s->sub.trees.table;
282 t = zlib_inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f),
283 s->sub.trees.blens, &bl, &bd, &tl, &td,
284 s->hufts, z);
285 if (t != Z_OK)
286 {
287 if (t == (uInt)Z_DATA_ERROR)
288 s->mode = B_BAD;
289 r = t;
290 LEAVE
291 }
292 if ((c = zlib_inflate_codes_new(bl, bd, tl, td, z)) == NULL)
293 {
294 r = Z_MEM_ERROR;
295 LEAVE
296 }
297 s->sub.decode.codes = c;
298 }
299 s->mode = CODES;
300 case CODES:
301 UPDATE
302 if ((r = zlib_inflate_codes(s, z, r)) != Z_STREAM_END)
303 return zlib_inflate_flush(s, z, r);
304 r = Z_OK;
305 zlib_inflate_codes_free(s->sub.decode.codes, z);
306 LOAD
307 if (!s->last)
308 {
309 s->mode = TYPE;
310 break;
311 }
312 s->mode = DRY;
313 case DRY:
314 FLUSH
315 if (s->read != s->write)
316 LEAVE
317 s->mode = B_DONE;
318 case B_DONE:
319 r = Z_STREAM_END;
320 LEAVE
321 case B_BAD:
322 r = Z_DATA_ERROR;
323 LEAVE
324 default:
325 r = Z_STREAM_ERROR;
326 LEAVE
327 }
328}
329
330
331int zlib_inflate_blocks_free(
332 inflate_blocks_statef *s,
333 z_streamp z
334)
335{
336 zlib_inflate_blocks_reset(s, z, NULL);
337 return Z_OK;
338}
339
340
341#if 0
342void zlib_inflate_set_dictionary(
343 inflate_blocks_statef *s,
344 const Byte *d,
345 uInt n
346)
347{
348 memcpy(s->window, d, n);
349 s->read = s->write = s->window + n;
350}
351#endif /* 0 */
352
353
354/* Returns true if inflate is currently at the end of a block generated
355 * by Z_SYNC_FLUSH or Z_FULL_FLUSH.
356 * IN assertion: s != NULL
357 */
358#if 0
359int zlib_inflate_blocks_sync_point(
360 inflate_blocks_statef *s
361)
362{
363 return s->mode == LENS;
364}
365#endif /* 0 */
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