Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | #define DEBG(x) |
2 | #define DEBG1(x) | |
3 | /* inflate.c -- Not copyrighted 1992 by Mark Adler | |
4 | version c10p1, 10 January 1993 */ | |
5 | ||
6 | /* | |
7 | * Adapted for booting Linux by Hannu Savolainen 1993 | |
8 | * based on gzip-1.0.3 | |
9 | * | |
10 | * Nicolas Pitre <nico@cam.org>, 1999/04/14 : | |
11 | * Little mods for all variable to reside either into rodata or bss segments | |
12 | * by marking constant variables with 'const' and initializing all the others | |
13 | * at run-time only. This allows for the kernel uncompressor to run | |
14 | * directly from Flash or ROM memory on embedded systems. | |
15 | */ | |
16 | ||
17 | /* | |
18 | Inflate deflated (PKZIP's method 8 compressed) data. The compression | |
19 | method searches for as much of the current string of bytes (up to a | |
20 | length of 258) in the previous 32 K bytes. If it doesn't find any | |
21 | matches (of at least length 3), it codes the next byte. Otherwise, it | |
22 | codes the length of the matched string and its distance backwards from | |
23 | the current position. There is a single Huffman code that codes both | |
24 | single bytes (called "literals") and match lengths. A second Huffman | |
25 | code codes the distance information, which follows a length code. Each | |
26 | length or distance code actually represents a base value and a number | |
27 | of "extra" (sometimes zero) bits to get to add to the base value. At | |
28 | the end of each deflated block is a special end-of-block (EOB) literal/ | |
29 | length code. The decoding process is basically: get a literal/length | |
30 | code; if EOB then done; if a literal, emit the decoded byte; if a | |
31 | length then get the distance and emit the referred-to bytes from the | |
32 | sliding window of previously emitted data. | |
33 | ||
34 | There are (currently) three kinds of inflate blocks: stored, fixed, and | |
35 | dynamic. The compressor deals with some chunk of data at a time, and | |
36 | decides which method to use on a chunk-by-chunk basis. A chunk might | |
37 | typically be 32 K or 64 K. If the chunk is incompressible, then the | |
38 | "stored" method is used. In this case, the bytes are simply stored as | |
39 | is, eight bits per byte, with none of the above coding. The bytes are | |
40 | preceded by a count, since there is no longer an EOB code. | |
41 | ||
42 | If the data is compressible, then either the fixed or dynamic methods | |
43 | are used. In the dynamic method, the compressed data is preceded by | |
44 | an encoding of the literal/length and distance Huffman codes that are | |
45 | to be used to decode this block. The representation is itself Huffman | |
46 | coded, and so is preceded by a description of that code. These code | |
47 | descriptions take up a little space, and so for small blocks, there is | |
48 | a predefined set of codes, called the fixed codes. The fixed method is | |
49 | used if the block codes up smaller that way (usually for quite small | |
50 | chunks), otherwise the dynamic method is used. In the latter case, the | |
51 | codes are customized to the probabilities in the current block, and so | |
52 | can code it much better than the pre-determined fixed codes. | |
53 | ||
54 | The Huffman codes themselves are decoded using a multi-level table | |
55 | lookup, in order to maximize the speed of decoding plus the speed of | |
56 | building the decoding tables. See the comments below that precede the | |
57 | lbits and dbits tuning parameters. | |
58 | */ | |
59 | ||
60 | ||
61 | /* | |
62 | Notes beyond the 1.93a appnote.txt: | |
63 | ||
64 | 1. Distance pointers never point before the beginning of the output | |
65 | stream. | |
66 | 2. Distance pointers can point back across blocks, up to 32k away. | |
67 | 3. There is an implied maximum of 7 bits for the bit length table and | |
68 | 15 bits for the actual data. | |
69 | 4. If only one code exists, then it is encoded using one bit. (Zero | |
70 | would be more efficient, but perhaps a little confusing.) If two | |
71 | codes exist, they are coded using one bit each (0 and 1). | |
72 | 5. There is no way of sending zero distance codes--a dummy must be | |
73 | sent if there are none. (History: a pre 2.0 version of PKZIP would | |
74 | store blocks with no distance codes, but this was discovered to be | |
75 | too harsh a criterion.) Valid only for 1.93a. 2.04c does allow | |
76 | zero distance codes, which is sent as one code of zero bits in | |
77 | length. | |
78 | 6. There are up to 286 literal/length codes. Code 256 represents the | |
79 | end-of-block. Note however that the static length tree defines | |
80 | 288 codes just to fill out the Huffman codes. Codes 286 and 287 | |
81 | cannot be used though, since there is no length base or extra bits | |
82 | defined for them. Similarly, there are up to 30 distance codes. | |
83 | However, static trees define 32 codes (all 5 bits) to fill out the | |
84 | Huffman codes, but the last two had better not show up in the data. | |
85 | 7. Unzip can check dynamic Huffman blocks for complete code sets. | |
86 | The exception is that a single code would not be complete (see #4). | |
87 | 8. The five bits following the block type is really the number of | |
88 | literal codes sent minus 257. | |
89 | 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits | |
90 | (1+6+6). Therefore, to output three times the length, you output | |
91 | three codes (1+1+1), whereas to output four times the same length, | |
92 | you only need two codes (1+3). Hmm. | |
93 | 10. In the tree reconstruction algorithm, Code = Code + Increment | |
94 | only if BitLength(i) is not zero. (Pretty obvious.) | |
95 | 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19) | |
96 | 12. Note: length code 284 can represent 227-258, but length code 285 | |
97 | really is 258. The last length deserves its own, short code | |
98 | since it gets used a lot in very redundant files. The length | |
99 | 258 is special since 258 - 3 (the min match length) is 255. | |
100 | 13. The literal/length and distance code bit lengths are read as a | |
101 | single stream of lengths. It is possible (and advantageous) for | |
102 | a repeat code (16, 17, or 18) to go across the boundary between | |
103 | the two sets of lengths. | |
104 | */ | |
105 | #include <linux/compiler.h> | |
106 | ||
107 | #ifdef RCSID | |
108 | static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #"; | |
109 | #endif | |
110 | ||
111 | #ifndef STATIC | |
112 | ||
113 | #if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H) | |
114 | # include <sys/types.h> | |
115 | # include <stdlib.h> | |
116 | #endif | |
117 | ||
118 | #include "gzip.h" | |
119 | #define STATIC | |
120 | #endif /* !STATIC */ | |
121 | ||
122 | #ifndef INIT | |
123 | #define INIT | |
124 | #endif | |
125 | ||
126 | #define slide window | |
127 | ||
128 | /* Huffman code lookup table entry--this entry is four bytes for machines | |
129 | that have 16-bit pointers (e.g. PC's in the small or medium model). | |
130 | Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16 | |
131 | means that v is a literal, 16 < e < 32 means that v is a pointer to | |
132 | the next table, which codes e - 16 bits, and lastly e == 99 indicates | |
133 | an unused code. If a code with e == 99 is looked up, this implies an | |
134 | error in the data. */ | |
135 | struct huft { | |
136 | uch e; /* number of extra bits or operation */ | |
137 | uch b; /* number of bits in this code or subcode */ | |
138 | union { | |
139 | ush n; /* literal, length base, or distance base */ | |
140 | struct huft *t; /* pointer to next level of table */ | |
141 | } v; | |
142 | }; | |
143 | ||
144 | ||
145 | /* Function prototypes */ | |
146 | STATIC int INIT huft_build OF((unsigned *, unsigned, unsigned, | |
147 | const ush *, const ush *, struct huft **, int *)); | |
148 | STATIC int INIT huft_free OF((struct huft *)); | |
149 | STATIC int INIT inflate_codes OF((struct huft *, struct huft *, int, int)); | |
150 | STATIC int INIT inflate_stored OF((void)); | |
151 | STATIC int INIT inflate_fixed OF((void)); | |
152 | STATIC int INIT inflate_dynamic OF((void)); | |
153 | STATIC int INIT inflate_block OF((int *)); | |
154 | STATIC int INIT inflate OF((void)); | |
155 | ||
156 | ||
157 | /* The inflate algorithm uses a sliding 32 K byte window on the uncompressed | |
158 | stream to find repeated byte strings. This is implemented here as a | |
159 | circular buffer. The index is updated simply by incrementing and then | |
160 | ANDing with 0x7fff (32K-1). */ | |
161 | /* It is left to other modules to supply the 32 K area. It is assumed | |
162 | to be usable as if it were declared "uch slide[32768];" or as just | |
163 | "uch *slide;" and then malloc'ed in the latter case. The definition | |
164 | must be in unzip.h, included above. */ | |
165 | /* unsigned wp; current position in slide */ | |
166 | #define wp outcnt | |
167 | #define flush_output(w) (wp=(w),flush_window()) | |
168 | ||
169 | /* Tables for deflate from PKZIP's appnote.txt. */ | |
170 | static const unsigned border[] = { /* Order of the bit length code lengths */ | |
171 | 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; | |
172 | static const ush cplens[] = { /* Copy lengths for literal codes 257..285 */ | |
173 | 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, | |
174 | 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; | |
175 | /* note: see note #13 above about the 258 in this list. */ | |
176 | static const ush cplext[] = { /* Extra bits for literal codes 257..285 */ | |
177 | 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, | |
178 | 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */ | |
179 | static const ush cpdist[] = { /* Copy offsets for distance codes 0..29 */ | |
180 | 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, | |
181 | 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, | |
182 | 8193, 12289, 16385, 24577}; | |
183 | static const ush cpdext[] = { /* Extra bits for distance codes */ | |
184 | 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, | |
185 | 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, | |
186 | 12, 12, 13, 13}; | |
187 | ||
188 | ||
189 | ||
190 | /* Macros for inflate() bit peeking and grabbing. | |
191 | The usage is: | |
192 | ||
193 | NEEDBITS(j) | |
194 | x = b & mask_bits[j]; | |
195 | DUMPBITS(j) | |
196 | ||
197 | where NEEDBITS makes sure that b has at least j bits in it, and | |
198 | DUMPBITS removes the bits from b. The macros use the variable k | |
199 | for the number of bits in b. Normally, b and k are register | |
200 | variables for speed, and are initialized at the beginning of a | |
201 | routine that uses these macros from a global bit buffer and count. | |
202 | ||
203 | If we assume that EOB will be the longest code, then we will never | |
204 | ask for bits with NEEDBITS that are beyond the end of the stream. | |
205 | So, NEEDBITS should not read any more bytes than are needed to | |
206 | meet the request. Then no bytes need to be "returned" to the buffer | |
207 | at the end of the last block. | |
208 | ||
209 | However, this assumption is not true for fixed blocks--the EOB code | |
210 | is 7 bits, but the other literal/length codes can be 8 or 9 bits. | |
211 | (The EOB code is shorter than other codes because fixed blocks are | |
212 | generally short. So, while a block always has an EOB, many other | |
213 | literal/length codes have a significantly lower probability of | |
214 | showing up at all.) However, by making the first table have a | |
215 | lookup of seven bits, the EOB code will be found in that first | |
216 | lookup, and so will not require that too many bits be pulled from | |
217 | the stream. | |
218 | */ | |
219 | ||
220 | STATIC ulg bb; /* bit buffer */ | |
221 | STATIC unsigned bk; /* bits in bit buffer */ | |
222 | ||
223 | STATIC const ush mask_bits[] = { | |
224 | 0x0000, | |
225 | 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, | |
226 | 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff | |
227 | }; | |
228 | ||
229 | #define NEXTBYTE() ({ int v = get_byte(); if (v < 0) goto underrun; (uch)v; }) | |
230 | #define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}} | |
231 | #define DUMPBITS(n) {b>>=(n);k-=(n);} | |
232 | ||
2d6ffcca TP |
233 | #ifndef NO_INFLATE_MALLOC |
234 | /* A trivial malloc implementation, adapted from | |
235 | * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994 | |
236 | */ | |
237 | ||
238 | static unsigned long malloc_ptr; | |
239 | static int malloc_count; | |
240 | ||
241 | static void *malloc(int size) | |
242 | { | |
243 | void *p; | |
244 | ||
245 | if (size < 0) | |
246 | error("Malloc error"); | |
247 | if (!malloc_ptr) | |
248 | malloc_ptr = free_mem_ptr; | |
249 | ||
250 | malloc_ptr = (malloc_ptr + 3) & ~3; /* Align */ | |
251 | ||
252 | p = (void *)malloc_ptr; | |
253 | malloc_ptr += size; | |
254 | ||
255 | if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr) | |
256 | error("Out of memory"); | |
257 | ||
258 | malloc_count++; | |
259 | return p; | |
260 | } | |
261 | ||
262 | static void free(void *where) | |
263 | { | |
264 | malloc_count--; | |
265 | if (!malloc_count) | |
266 | malloc_ptr = free_mem_ptr; | |
267 | } | |
268 | #else | |
269 | #define malloc(a) kmalloc(a, GFP_KERNEL) | |
270 | #define free(a) kfree(a) | |
271 | #endif | |
1da177e4 LT |
272 | |
273 | /* | |
274 | Huffman code decoding is performed using a multi-level table lookup. | |
275 | The fastest way to decode is to simply build a lookup table whose | |
276 | size is determined by the longest code. However, the time it takes | |
277 | to build this table can also be a factor if the data being decoded | |
278 | is not very long. The most common codes are necessarily the | |
279 | shortest codes, so those codes dominate the decoding time, and hence | |
280 | the speed. The idea is you can have a shorter table that decodes the | |
281 | shorter, more probable codes, and then point to subsidiary tables for | |
282 | the longer codes. The time it costs to decode the longer codes is | |
283 | then traded against the time it takes to make longer tables. | |
284 | ||
285 | This results of this trade are in the variables lbits and dbits | |
286 | below. lbits is the number of bits the first level table for literal/ | |
287 | length codes can decode in one step, and dbits is the same thing for | |
288 | the distance codes. Subsequent tables are also less than or equal to | |
289 | those sizes. These values may be adjusted either when all of the | |
290 | codes are shorter than that, in which case the longest code length in | |
291 | bits is used, or when the shortest code is *longer* than the requested | |
292 | table size, in which case the length of the shortest code in bits is | |
293 | used. | |
294 | ||
295 | There are two different values for the two tables, since they code a | |
296 | different number of possibilities each. The literal/length table | |
297 | codes 286 possible values, or in a flat code, a little over eight | |
298 | bits. The distance table codes 30 possible values, or a little less | |
299 | than five bits, flat. The optimum values for speed end up being | |
300 | about one bit more than those, so lbits is 8+1 and dbits is 5+1. | |
301 | The optimum values may differ though from machine to machine, and | |
302 | possibly even between compilers. Your mileage may vary. | |
303 | */ | |
304 | ||
305 | ||
306 | STATIC const int lbits = 9; /* bits in base literal/length lookup table */ | |
307 | STATIC const int dbits = 6; /* bits in base distance lookup table */ | |
308 | ||
309 | ||
310 | /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */ | |
311 | #define BMAX 16 /* maximum bit length of any code (16 for explode) */ | |
312 | #define N_MAX 288 /* maximum number of codes in any set */ | |
313 | ||
314 | ||
315 | STATIC unsigned hufts; /* track memory usage */ | |
316 | ||
317 | ||
318 | STATIC int INIT huft_build( | |
319 | unsigned *b, /* code lengths in bits (all assumed <= BMAX) */ | |
320 | unsigned n, /* number of codes (assumed <= N_MAX) */ | |
321 | unsigned s, /* number of simple-valued codes (0..s-1) */ | |
322 | const ush *d, /* list of base values for non-simple codes */ | |
323 | const ush *e, /* list of extra bits for non-simple codes */ | |
324 | struct huft **t, /* result: starting table */ | |
325 | int *m /* maximum lookup bits, returns actual */ | |
326 | ) | |
327 | /* Given a list of code lengths and a maximum table size, make a set of | |
328 | tables to decode that set of codes. Return zero on success, one if | |
329 | the given code set is incomplete (the tables are still built in this | |
330 | case), two if the input is invalid (all zero length codes or an | |
331 | oversubscribed set of lengths), and three if not enough memory. */ | |
332 | { | |
333 | unsigned a; /* counter for codes of length k */ | |
1da177e4 LT |
334 | unsigned f; /* i repeats in table every f entries */ |
335 | int g; /* maximum code length */ | |
336 | int h; /* table level */ | |
337 | register unsigned i; /* counter, current code */ | |
338 | register unsigned j; /* counter */ | |
339 | register int k; /* number of bits in current code */ | |
340 | int l; /* bits per table (returned in m) */ | |
341 | register unsigned *p; /* pointer into c[], b[], or v[] */ | |
342 | register struct huft *q; /* points to current table */ | |
343 | struct huft r; /* table entry for structure assignment */ | |
1da177e4 | 344 | register int w; /* bits before this table == (l * h) */ |
1da177e4 LT |
345 | unsigned *xp; /* pointer into x */ |
346 | int y; /* number of dummy codes added */ | |
347 | unsigned z; /* number of entries in current table */ | |
35c74226 JF |
348 | struct { |
349 | unsigned c[BMAX+1]; /* bit length count table */ | |
350 | struct huft *u[BMAX]; /* table stack */ | |
351 | unsigned v[N_MAX]; /* values in order of bit length */ | |
352 | unsigned x[BMAX+1]; /* bit offsets, then code stack */ | |
353 | } *stk; | |
354 | unsigned *c, *v, *x; | |
355 | struct huft **u; | |
356 | int ret; | |
1da177e4 LT |
357 | |
358 | DEBG("huft1 "); | |
359 | ||
35c74226 JF |
360 | stk = malloc(sizeof(*stk)); |
361 | if (stk == NULL) | |
362 | return 3; /* out of memory */ | |
363 | ||
364 | c = stk->c; | |
365 | v = stk->v; | |
366 | x = stk->x; | |
367 | u = stk->u; | |
368 | ||
1da177e4 | 369 | /* Generate counts for each bit length */ |
35c74226 | 370 | memzero(stk->c, sizeof(stk->c)); |
1da177e4 LT |
371 | p = b; i = n; |
372 | do { | |
373 | Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"), | |
374 | n-i, *p)); | |
375 | c[*p]++; /* assume all entries <= BMAX */ | |
376 | p++; /* Can't combine with above line (Solaris bug) */ | |
377 | } while (--i); | |
378 | if (c[0] == n) /* null input--all zero length codes */ | |
379 | { | |
380 | *t = (struct huft *)NULL; | |
381 | *m = 0; | |
35c74226 JF |
382 | ret = 2; |
383 | goto out; | |
1da177e4 LT |
384 | } |
385 | ||
386 | DEBG("huft2 "); | |
387 | ||
388 | /* Find minimum and maximum length, bound *m by those */ | |
389 | l = *m; | |
390 | for (j = 1; j <= BMAX; j++) | |
391 | if (c[j]) | |
392 | break; | |
393 | k = j; /* minimum code length */ | |
394 | if ((unsigned)l < j) | |
395 | l = j; | |
396 | for (i = BMAX; i; i--) | |
397 | if (c[i]) | |
398 | break; | |
399 | g = i; /* maximum code length */ | |
400 | if ((unsigned)l > i) | |
401 | l = i; | |
402 | *m = l; | |
403 | ||
404 | DEBG("huft3 "); | |
405 | ||
406 | /* Adjust last length count to fill out codes, if needed */ | |
407 | for (y = 1 << j; j < i; j++, y <<= 1) | |
35c74226 JF |
408 | if ((y -= c[j]) < 0) { |
409 | ret = 2; /* bad input: more codes than bits */ | |
410 | goto out; | |
411 | } | |
412 | if ((y -= c[i]) < 0) { | |
413 | ret = 2; | |
414 | goto out; | |
415 | } | |
1da177e4 LT |
416 | c[i] += y; |
417 | ||
418 | DEBG("huft4 "); | |
419 | ||
420 | /* Generate starting offsets into the value table for each length */ | |
421 | x[1] = j = 0; | |
422 | p = c + 1; xp = x + 2; | |
423 | while (--i) { /* note that i == g from above */ | |
424 | *xp++ = (j += *p++); | |
425 | } | |
426 | ||
427 | DEBG("huft5 "); | |
428 | ||
429 | /* Make a table of values in order of bit lengths */ | |
430 | p = b; i = 0; | |
431 | do { | |
432 | if ((j = *p++) != 0) | |
433 | v[x[j]++] = i; | |
434 | } while (++i < n); | |
4aad724d | 435 | n = x[g]; /* set n to length of v */ |
1da177e4 LT |
436 | |
437 | DEBG("h6 "); | |
438 | ||
439 | /* Generate the Huffman codes and for each, make the table entries */ | |
440 | x[0] = i = 0; /* first Huffman code is zero */ | |
441 | p = v; /* grab values in bit order */ | |
442 | h = -1; /* no tables yet--level -1 */ | |
443 | w = -l; /* bits decoded == (l * h) */ | |
444 | u[0] = (struct huft *)NULL; /* just to keep compilers happy */ | |
445 | q = (struct huft *)NULL; /* ditto */ | |
446 | z = 0; /* ditto */ | |
447 | DEBG("h6a "); | |
448 | ||
449 | /* go through the bit lengths (k already is bits in shortest code) */ | |
450 | for (; k <= g; k++) | |
451 | { | |
452 | DEBG("h6b "); | |
453 | a = c[k]; | |
454 | while (a--) | |
455 | { | |
456 | DEBG("h6b1 "); | |
457 | /* here i is the Huffman code of length k bits for value *p */ | |
458 | /* make tables up to required level */ | |
459 | while (k > w + l) | |
460 | { | |
461 | DEBG1("1 "); | |
462 | h++; | |
463 | w += l; /* previous table always l bits */ | |
464 | ||
465 | /* compute minimum size table less than or equal to l bits */ | |
466 | z = (z = g - w) > (unsigned)l ? l : z; /* upper limit on table size */ | |
467 | if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */ | |
468 | { /* too few codes for k-w bit table */ | |
469 | DEBG1("2 "); | |
470 | f -= a + 1; /* deduct codes from patterns left */ | |
471 | xp = c + k; | |
4aad724d TY |
472 | if (j < z) |
473 | while (++j < z) /* try smaller tables up to z bits */ | |
474 | { | |
475 | if ((f <<= 1) <= *++xp) | |
476 | break; /* enough codes to use up j bits */ | |
477 | f -= *xp; /* else deduct codes from patterns */ | |
478 | } | |
1da177e4 LT |
479 | } |
480 | DEBG1("3 "); | |
481 | z = 1 << j; /* table entries for j-bit table */ | |
482 | ||
483 | /* allocate and link in new table */ | |
484 | if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) == | |
485 | (struct huft *)NULL) | |
486 | { | |
487 | if (h) | |
488 | huft_free(u[0]); | |
35c74226 JF |
489 | ret = 3; /* not enough memory */ |
490 | goto out; | |
1da177e4 LT |
491 | } |
492 | DEBG1("4 "); | |
493 | hufts += z + 1; /* track memory usage */ | |
494 | *t = q + 1; /* link to list for huft_free() */ | |
495 | *(t = &(q->v.t)) = (struct huft *)NULL; | |
496 | u[h] = ++q; /* table starts after link */ | |
497 | ||
498 | DEBG1("5 "); | |
499 | /* connect to last table, if there is one */ | |
500 | if (h) | |
501 | { | |
502 | x[h] = i; /* save pattern for backing up */ | |
503 | r.b = (uch)l; /* bits to dump before this table */ | |
504 | r.e = (uch)(16 + j); /* bits in this table */ | |
505 | r.v.t = q; /* pointer to this table */ | |
506 | j = i >> (w - l); /* (get around Turbo C bug) */ | |
507 | u[h-1][j] = r; /* connect to last table */ | |
508 | } | |
509 | DEBG1("6 "); | |
510 | } | |
511 | DEBG("h6c "); | |
512 | ||
513 | /* set up table entry in r */ | |
514 | r.b = (uch)(k - w); | |
515 | if (p >= v + n) | |
516 | r.e = 99; /* out of values--invalid code */ | |
517 | else if (*p < s) | |
518 | { | |
519 | r.e = (uch)(*p < 256 ? 16 : 15); /* 256 is end-of-block code */ | |
520 | r.v.n = (ush)(*p); /* simple code is just the value */ | |
521 | p++; /* one compiler does not like *p++ */ | |
522 | } | |
523 | else | |
524 | { | |
525 | r.e = (uch)e[*p - s]; /* non-simple--look up in lists */ | |
526 | r.v.n = d[*p++ - s]; | |
527 | } | |
528 | DEBG("h6d "); | |
529 | ||
530 | /* fill code-like entries with r */ | |
531 | f = 1 << (k - w); | |
532 | for (j = i >> w; j < z; j += f) | |
533 | q[j] = r; | |
534 | ||
535 | /* backwards increment the k-bit code i */ | |
536 | for (j = 1 << (k - 1); i & j; j >>= 1) | |
537 | i ^= j; | |
538 | i ^= j; | |
539 | ||
540 | /* backup over finished tables */ | |
541 | while ((i & ((1 << w) - 1)) != x[h]) | |
542 | { | |
543 | h--; /* don't need to update q */ | |
544 | w -= l; | |
545 | } | |
546 | DEBG("h6e "); | |
547 | } | |
548 | DEBG("h6f "); | |
549 | } | |
550 | ||
551 | DEBG("huft7 "); | |
552 | ||
553 | /* Return true (1) if we were given an incomplete table */ | |
35c74226 JF |
554 | ret = y != 0 && g != 1; |
555 | ||
556 | out: | |
557 | free(stk); | |
558 | return ret; | |
1da177e4 LT |
559 | } |
560 | ||
561 | ||
562 | ||
563 | STATIC int INIT huft_free( | |
564 | struct huft *t /* table to free */ | |
565 | ) | |
566 | /* Free the malloc'ed tables built by huft_build(), which makes a linked | |
567 | list of the tables it made, with the links in a dummy first entry of | |
568 | each table. */ | |
569 | { | |
570 | register struct huft *p, *q; | |
571 | ||
572 | ||
573 | /* Go through linked list, freeing from the malloced (t[-1]) address. */ | |
574 | p = t; | |
575 | while (p != (struct huft *)NULL) | |
576 | { | |
577 | q = (--p)->v.t; | |
578 | free((char*)p); | |
579 | p = q; | |
580 | } | |
581 | return 0; | |
582 | } | |
583 | ||
584 | ||
585 | STATIC int INIT inflate_codes( | |
586 | struct huft *tl, /* literal/length decoder tables */ | |
587 | struct huft *td, /* distance decoder tables */ | |
588 | int bl, /* number of bits decoded by tl[] */ | |
589 | int bd /* number of bits decoded by td[] */ | |
590 | ) | |
591 | /* inflate (decompress) the codes in a deflated (compressed) block. | |
592 | Return an error code or zero if it all goes ok. */ | |
593 | { | |
594 | register unsigned e; /* table entry flag/number of extra bits */ | |
595 | unsigned n, d; /* length and index for copy */ | |
596 | unsigned w; /* current window position */ | |
597 | struct huft *t; /* pointer to table entry */ | |
598 | unsigned ml, md; /* masks for bl and bd bits */ | |
599 | register ulg b; /* bit buffer */ | |
600 | register unsigned k; /* number of bits in bit buffer */ | |
601 | ||
602 | ||
603 | /* make local copies of globals */ | |
604 | b = bb; /* initialize bit buffer */ | |
605 | k = bk; | |
606 | w = wp; /* initialize window position */ | |
607 | ||
608 | /* inflate the coded data */ | |
609 | ml = mask_bits[bl]; /* precompute masks for speed */ | |
610 | md = mask_bits[bd]; | |
611 | for (;;) /* do until end of block */ | |
612 | { | |
613 | NEEDBITS((unsigned)bl) | |
614 | if ((e = (t = tl + ((unsigned)b & ml))->e) > 16) | |
615 | do { | |
616 | if (e == 99) | |
617 | return 1; | |
618 | DUMPBITS(t->b) | |
619 | e -= 16; | |
620 | NEEDBITS(e) | |
621 | } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16); | |
622 | DUMPBITS(t->b) | |
623 | if (e == 16) /* then it's a literal */ | |
624 | { | |
625 | slide[w++] = (uch)t->v.n; | |
626 | Tracevv((stderr, "%c", slide[w-1])); | |
627 | if (w == WSIZE) | |
628 | { | |
629 | flush_output(w); | |
630 | w = 0; | |
631 | } | |
632 | } | |
633 | else /* it's an EOB or a length */ | |
634 | { | |
635 | /* exit if end of block */ | |
636 | if (e == 15) | |
637 | break; | |
638 | ||
639 | /* get length of block to copy */ | |
640 | NEEDBITS(e) | |
641 | n = t->v.n + ((unsigned)b & mask_bits[e]); | |
642 | DUMPBITS(e); | |
643 | ||
644 | /* decode distance of block to copy */ | |
645 | NEEDBITS((unsigned)bd) | |
646 | if ((e = (t = td + ((unsigned)b & md))->e) > 16) | |
647 | do { | |
648 | if (e == 99) | |
649 | return 1; | |
650 | DUMPBITS(t->b) | |
651 | e -= 16; | |
652 | NEEDBITS(e) | |
653 | } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16); | |
654 | DUMPBITS(t->b) | |
655 | NEEDBITS(e) | |
656 | d = w - t->v.n - ((unsigned)b & mask_bits[e]); | |
657 | DUMPBITS(e) | |
658 | Tracevv((stderr,"\\[%d,%d]", w-d, n)); | |
659 | ||
660 | /* do the copy */ | |
661 | do { | |
662 | n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); | |
663 | #if !defined(NOMEMCPY) && !defined(DEBUG) | |
664 | if (w - d >= e) /* (this test assumes unsigned comparison) */ | |
665 | { | |
666 | memcpy(slide + w, slide + d, e); | |
667 | w += e; | |
668 | d += e; | |
669 | } | |
670 | else /* do it slow to avoid memcpy() overlap */ | |
671 | #endif /* !NOMEMCPY */ | |
672 | do { | |
673 | slide[w++] = slide[d++]; | |
674 | Tracevv((stderr, "%c", slide[w-1])); | |
675 | } while (--e); | |
676 | if (w == WSIZE) | |
677 | { | |
678 | flush_output(w); | |
679 | w = 0; | |
680 | } | |
681 | } while (n); | |
682 | } | |
683 | } | |
684 | ||
685 | ||
686 | /* restore the globals from the locals */ | |
687 | wp = w; /* restore global window pointer */ | |
688 | bb = b; /* restore global bit buffer */ | |
689 | bk = k; | |
690 | ||
691 | /* done */ | |
692 | return 0; | |
693 | ||
694 | underrun: | |
695 | return 4; /* Input underrun */ | |
696 | } | |
697 | ||
698 | ||
699 | ||
700 | STATIC int INIT inflate_stored(void) | |
701 | /* "decompress" an inflated type 0 (stored) block. */ | |
702 | { | |
703 | unsigned n; /* number of bytes in block */ | |
704 | unsigned w; /* current window position */ | |
705 | register ulg b; /* bit buffer */ | |
706 | register unsigned k; /* number of bits in bit buffer */ | |
707 | ||
708 | DEBG("<stor"); | |
709 | ||
710 | /* make local copies of globals */ | |
711 | b = bb; /* initialize bit buffer */ | |
712 | k = bk; | |
713 | w = wp; /* initialize window position */ | |
714 | ||
715 | ||
716 | /* go to byte boundary */ | |
717 | n = k & 7; | |
718 | DUMPBITS(n); | |
719 | ||
720 | ||
721 | /* get the length and its complement */ | |
722 | NEEDBITS(16) | |
723 | n = ((unsigned)b & 0xffff); | |
724 | DUMPBITS(16) | |
725 | NEEDBITS(16) | |
726 | if (n != (unsigned)((~b) & 0xffff)) | |
727 | return 1; /* error in compressed data */ | |
728 | DUMPBITS(16) | |
729 | ||
730 | ||
731 | /* read and output the compressed data */ | |
732 | while (n--) | |
733 | { | |
734 | NEEDBITS(8) | |
735 | slide[w++] = (uch)b; | |
736 | if (w == WSIZE) | |
737 | { | |
738 | flush_output(w); | |
739 | w = 0; | |
740 | } | |
741 | DUMPBITS(8) | |
742 | } | |
743 | ||
744 | ||
745 | /* restore the globals from the locals */ | |
746 | wp = w; /* restore global window pointer */ | |
747 | bb = b; /* restore global bit buffer */ | |
748 | bk = k; | |
749 | ||
750 | DEBG(">"); | |
751 | return 0; | |
752 | ||
753 | underrun: | |
754 | return 4; /* Input underrun */ | |
755 | } | |
756 | ||
757 | ||
758 | /* | |
759 | * We use `noinline' here to prevent gcc-3.5 from using too much stack space | |
760 | */ | |
761 | STATIC int noinline INIT inflate_fixed(void) | |
762 | /* decompress an inflated type 1 (fixed Huffman codes) block. We should | |
763 | either replace this with a custom decoder, or at least precompute the | |
764 | Huffman tables. */ | |
765 | { | |
766 | int i; /* temporary variable */ | |
767 | struct huft *tl; /* literal/length code table */ | |
768 | struct huft *td; /* distance code table */ | |
769 | int bl; /* lookup bits for tl */ | |
770 | int bd; /* lookup bits for td */ | |
35c74226 | 771 | unsigned *l; /* length list for huft_build */ |
1da177e4 LT |
772 | |
773 | DEBG("<fix"); | |
774 | ||
35c74226 JF |
775 | l = malloc(sizeof(*l) * 288); |
776 | if (l == NULL) | |
777 | return 3; /* out of memory */ | |
778 | ||
1da177e4 LT |
779 | /* set up literal table */ |
780 | for (i = 0; i < 144; i++) | |
781 | l[i] = 8; | |
782 | for (; i < 256; i++) | |
783 | l[i] = 9; | |
784 | for (; i < 280; i++) | |
785 | l[i] = 7; | |
786 | for (; i < 288; i++) /* make a complete, but wrong code set */ | |
787 | l[i] = 8; | |
788 | bl = 7; | |
35c74226 JF |
789 | if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) { |
790 | free(l); | |
1da177e4 | 791 | return i; |
35c74226 | 792 | } |
1da177e4 LT |
793 | |
794 | /* set up distance table */ | |
795 | for (i = 0; i < 30; i++) /* make an incomplete code set */ | |
796 | l[i] = 5; | |
797 | bd = 5; | |
798 | if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) | |
799 | { | |
800 | huft_free(tl); | |
35c74226 | 801 | free(l); |
1da177e4 LT |
802 | |
803 | DEBG(">"); | |
804 | return i; | |
805 | } | |
806 | ||
807 | ||
808 | /* decompress until an end-of-block code */ | |
35c74226 JF |
809 | if (inflate_codes(tl, td, bl, bd)) { |
810 | free(l); | |
1da177e4 | 811 | return 1; |
35c74226 | 812 | } |
1da177e4 LT |
813 | |
814 | /* free the decoding tables, return */ | |
35c74226 | 815 | free(l); |
1da177e4 LT |
816 | huft_free(tl); |
817 | huft_free(td); | |
818 | return 0; | |
819 | } | |
820 | ||
821 | ||
822 | /* | |
823 | * We use `noinline' here to prevent gcc-3.5 from using too much stack space | |
824 | */ | |
825 | STATIC int noinline INIT inflate_dynamic(void) | |
826 | /* decompress an inflated type 2 (dynamic Huffman codes) block. */ | |
827 | { | |
828 | int i; /* temporary variables */ | |
829 | unsigned j; | |
830 | unsigned l; /* last length */ | |
831 | unsigned m; /* mask for bit lengths table */ | |
832 | unsigned n; /* number of lengths to get */ | |
833 | struct huft *tl; /* literal/length code table */ | |
834 | struct huft *td; /* distance code table */ | |
835 | int bl; /* lookup bits for tl */ | |
836 | int bd; /* lookup bits for td */ | |
837 | unsigned nb; /* number of bit length codes */ | |
838 | unsigned nl; /* number of literal/length codes */ | |
839 | unsigned nd; /* number of distance codes */ | |
39b7ee06 | 840 | unsigned *ll; /* literal/length and distance code lengths */ |
1da177e4 LT |
841 | register ulg b; /* bit buffer */ |
842 | register unsigned k; /* number of bits in bit buffer */ | |
39b7ee06 | 843 | int ret; |
1da177e4 LT |
844 | |
845 | DEBG("<dyn"); | |
846 | ||
39b7ee06 JF |
847 | #ifdef PKZIP_BUG_WORKAROUND |
848 | ll = malloc(sizeof(*ll) * (288+32)); /* literal/length and distance code lengths */ | |
849 | #else | |
850 | ll = malloc(sizeof(*ll) * (286+30)); /* literal/length and distance code lengths */ | |
851 | #endif | |
852 | ||
22caa041 JM |
853 | if (ll == NULL) |
854 | return 1; | |
855 | ||
1da177e4 LT |
856 | /* make local bit buffer */ |
857 | b = bb; | |
858 | k = bk; | |
859 | ||
860 | ||
861 | /* read in table lengths */ | |
862 | NEEDBITS(5) | |
863 | nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length codes */ | |
864 | DUMPBITS(5) | |
865 | NEEDBITS(5) | |
866 | nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */ | |
867 | DUMPBITS(5) | |
868 | NEEDBITS(4) | |
869 | nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */ | |
870 | DUMPBITS(4) | |
871 | #ifdef PKZIP_BUG_WORKAROUND | |
872 | if (nl > 288 || nd > 32) | |
873 | #else | |
874 | if (nl > 286 || nd > 30) | |
875 | #endif | |
39b7ee06 JF |
876 | { |
877 | ret = 1; /* bad lengths */ | |
878 | goto out; | |
879 | } | |
1da177e4 LT |
880 | |
881 | DEBG("dyn1 "); | |
882 | ||
883 | /* read in bit-length-code lengths */ | |
884 | for (j = 0; j < nb; j++) | |
885 | { | |
886 | NEEDBITS(3) | |
887 | ll[border[j]] = (unsigned)b & 7; | |
888 | DUMPBITS(3) | |
889 | } | |
890 | for (; j < 19; j++) | |
891 | ll[border[j]] = 0; | |
892 | ||
893 | DEBG("dyn2 "); | |
894 | ||
895 | /* build decoding table for trees--single level, 7 bit lookup */ | |
896 | bl = 7; | |
897 | if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) | |
898 | { | |
899 | if (i == 1) | |
900 | huft_free(tl); | |
39b7ee06 JF |
901 | ret = i; /* incomplete code set */ |
902 | goto out; | |
1da177e4 LT |
903 | } |
904 | ||
905 | DEBG("dyn3 "); | |
906 | ||
907 | /* read in literal and distance code lengths */ | |
908 | n = nl + nd; | |
909 | m = mask_bits[bl]; | |
910 | i = l = 0; | |
911 | while ((unsigned)i < n) | |
912 | { | |
913 | NEEDBITS((unsigned)bl) | |
914 | j = (td = tl + ((unsigned)b & m))->b; | |
915 | DUMPBITS(j) | |
916 | j = td->v.n; | |
917 | if (j < 16) /* length of code in bits (0..15) */ | |
918 | ll[i++] = l = j; /* save last length in l */ | |
919 | else if (j == 16) /* repeat last length 3 to 6 times */ | |
920 | { | |
921 | NEEDBITS(2) | |
922 | j = 3 + ((unsigned)b & 3); | |
923 | DUMPBITS(2) | |
39b7ee06 JF |
924 | if ((unsigned)i + j > n) { |
925 | ret = 1; | |
926 | goto out; | |
927 | } | |
1da177e4 LT |
928 | while (j--) |
929 | ll[i++] = l; | |
930 | } | |
931 | else if (j == 17) /* 3 to 10 zero length codes */ | |
932 | { | |
933 | NEEDBITS(3) | |
934 | j = 3 + ((unsigned)b & 7); | |
935 | DUMPBITS(3) | |
39b7ee06 JF |
936 | if ((unsigned)i + j > n) { |
937 | ret = 1; | |
938 | goto out; | |
939 | } | |
1da177e4 LT |
940 | while (j--) |
941 | ll[i++] = 0; | |
942 | l = 0; | |
943 | } | |
944 | else /* j == 18: 11 to 138 zero length codes */ | |
945 | { | |
946 | NEEDBITS(7) | |
947 | j = 11 + ((unsigned)b & 0x7f); | |
948 | DUMPBITS(7) | |
39b7ee06 JF |
949 | if ((unsigned)i + j > n) { |
950 | ret = 1; | |
951 | goto out; | |
952 | } | |
1da177e4 LT |
953 | while (j--) |
954 | ll[i++] = 0; | |
955 | l = 0; | |
956 | } | |
957 | } | |
958 | ||
959 | DEBG("dyn4 "); | |
960 | ||
961 | /* free decoding table for trees */ | |
962 | huft_free(tl); | |
963 | ||
964 | DEBG("dyn5 "); | |
965 | ||
966 | /* restore the global bit buffer */ | |
967 | bb = b; | |
968 | bk = k; | |
969 | ||
970 | DEBG("dyn5a "); | |
971 | ||
972 | /* build the decoding tables for literal/length and distance codes */ | |
973 | bl = lbits; | |
974 | if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) | |
975 | { | |
976 | DEBG("dyn5b "); | |
977 | if (i == 1) { | |
978 | error("incomplete literal tree"); | |
979 | huft_free(tl); | |
980 | } | |
39b7ee06 JF |
981 | ret = i; /* incomplete code set */ |
982 | goto out; | |
1da177e4 LT |
983 | } |
984 | DEBG("dyn5c "); | |
985 | bd = dbits; | |
986 | if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) | |
987 | { | |
988 | DEBG("dyn5d "); | |
989 | if (i == 1) { | |
990 | error("incomplete distance tree"); | |
991 | #ifdef PKZIP_BUG_WORKAROUND | |
992 | i = 0; | |
993 | } | |
994 | #else | |
995 | huft_free(td); | |
996 | } | |
997 | huft_free(tl); | |
39b7ee06 JF |
998 | ret = i; /* incomplete code set */ |
999 | goto out; | |
1da177e4 LT |
1000 | #endif |
1001 | } | |
1002 | ||
1003 | DEBG("dyn6 "); | |
1004 | ||
1005 | /* decompress until an end-of-block code */ | |
39b7ee06 JF |
1006 | if (inflate_codes(tl, td, bl, bd)) { |
1007 | ret = 1; | |
1008 | goto out; | |
1009 | } | |
1da177e4 LT |
1010 | |
1011 | DEBG("dyn7 "); | |
1012 | ||
1013 | /* free the decoding tables, return */ | |
1014 | huft_free(tl); | |
1015 | huft_free(td); | |
1016 | ||
1017 | DEBG(">"); | |
39b7ee06 JF |
1018 | ret = 0; |
1019 | out: | |
1020 | free(ll); | |
1021 | return ret; | |
1da177e4 | 1022 | |
39b7ee06 JF |
1023 | underrun: |
1024 | ret = 4; /* Input underrun */ | |
1025 | goto out; | |
1da177e4 LT |
1026 | } |
1027 | ||
1028 | ||
1029 | ||
1030 | STATIC int INIT inflate_block( | |
1031 | int *e /* last block flag */ | |
1032 | ) | |
1033 | /* decompress an inflated block */ | |
1034 | { | |
1035 | unsigned t; /* block type */ | |
1036 | register ulg b; /* bit buffer */ | |
1037 | register unsigned k; /* number of bits in bit buffer */ | |
1038 | ||
1039 | DEBG("<blk"); | |
1040 | ||
1041 | /* make local bit buffer */ | |
1042 | b = bb; | |
1043 | k = bk; | |
1044 | ||
1045 | ||
1046 | /* read in last block bit */ | |
1047 | NEEDBITS(1) | |
1048 | *e = (int)b & 1; | |
1049 | DUMPBITS(1) | |
1050 | ||
1051 | ||
1052 | /* read in block type */ | |
1053 | NEEDBITS(2) | |
1054 | t = (unsigned)b & 3; | |
1055 | DUMPBITS(2) | |
1056 | ||
1057 | ||
1058 | /* restore the global bit buffer */ | |
1059 | bb = b; | |
1060 | bk = k; | |
1061 | ||
1062 | /* inflate that block type */ | |
1063 | if (t == 2) | |
1064 | return inflate_dynamic(); | |
1065 | if (t == 0) | |
1066 | return inflate_stored(); | |
1067 | if (t == 1) | |
1068 | return inflate_fixed(); | |
1069 | ||
1070 | DEBG(">"); | |
1071 | ||
1072 | /* bad block type */ | |
1073 | return 2; | |
1074 | ||
1075 | underrun: | |
1076 | return 4; /* Input underrun */ | |
1077 | } | |
1078 | ||
1079 | ||
1080 | ||
1081 | STATIC int INIT inflate(void) | |
1082 | /* decompress an inflated entry */ | |
1083 | { | |
1084 | int e; /* last block flag */ | |
1085 | int r; /* result code */ | |
1086 | unsigned h; /* maximum struct huft's malloc'ed */ | |
1da177e4 LT |
1087 | |
1088 | /* initialize window, bit buffer */ | |
1089 | wp = 0; | |
1090 | bk = 0; | |
1091 | bb = 0; | |
1092 | ||
1093 | ||
1094 | /* decompress until the last block */ | |
1095 | h = 0; | |
1096 | do { | |
1097 | hufts = 0; | |
2d6ffcca TP |
1098 | #ifdef ARCH_HAS_DECOMP_WDOG |
1099 | arch_decomp_wdog(); | |
1100 | #endif | |
1101 | r = inflate_block(&e); | |
1102 | if (r) | |
1103 | return r; | |
1da177e4 LT |
1104 | if (hufts > h) |
1105 | h = hufts; | |
1106 | } while (!e); | |
1107 | ||
1108 | /* Undo too much lookahead. The next read will be byte aligned so we | |
1109 | * can discard unused bits in the last meaningful byte. | |
1110 | */ | |
1111 | while (bk >= 8) { | |
1112 | bk -= 8; | |
1113 | inptr--; | |
1114 | } | |
1115 | ||
1116 | /* flush out slide */ | |
1117 | flush_output(wp); | |
1118 | ||
1119 | ||
1120 | /* return success */ | |
1121 | #ifdef DEBUG | |
1122 | fprintf(stderr, "<%u> ", h); | |
1123 | #endif /* DEBUG */ | |
1124 | return 0; | |
1125 | } | |
1126 | ||
1127 | /********************************************************************** | |
1128 | * | |
1129 | * The following are support routines for inflate.c | |
1130 | * | |
1131 | **********************************************************************/ | |
1132 | ||
1133 | static ulg crc_32_tab[256]; | |
1134 | static ulg crc; /* initialized in makecrc() so it'll reside in bss */ | |
1135 | #define CRC_VALUE (crc ^ 0xffffffffUL) | |
1136 | ||
1137 | /* | |
1138 | * Code to compute the CRC-32 table. Borrowed from | |
1139 | * gzip-1.0.3/makecrc.c. | |
1140 | */ | |
1141 | ||
1142 | static void INIT | |
1143 | makecrc(void) | |
1144 | { | |
1145 | /* Not copyrighted 1990 Mark Adler */ | |
1146 | ||
1147 | unsigned long c; /* crc shift register */ | |
1148 | unsigned long e; /* polynomial exclusive-or pattern */ | |
1149 | int i; /* counter for all possible eight bit values */ | |
1150 | int k; /* byte being shifted into crc apparatus */ | |
1151 | ||
1152 | /* terms of polynomial defining this crc (except x^32): */ | |
1153 | static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; | |
1154 | ||
1155 | /* Make exclusive-or pattern from polynomial */ | |
1156 | e = 0; | |
1157 | for (i = 0; i < sizeof(p)/sizeof(int); i++) | |
1158 | e |= 1L << (31 - p[i]); | |
1159 | ||
1160 | crc_32_tab[0] = 0; | |
1161 | ||
1162 | for (i = 1; i < 256; i++) | |
1163 | { | |
1164 | c = 0; | |
1165 | for (k = i | 256; k != 1; k >>= 1) | |
1166 | { | |
1167 | c = c & 1 ? (c >> 1) ^ e : c >> 1; | |
1168 | if (k & 1) | |
1169 | c ^= e; | |
1170 | } | |
1171 | crc_32_tab[i] = c; | |
1172 | } | |
1173 | ||
1174 | /* this is initialized here so this code could reside in ROM */ | |
1175 | crc = (ulg)0xffffffffUL; /* shift register contents */ | |
1176 | } | |
1177 | ||
1178 | /* gzip flag byte */ | |
1179 | #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ | |
1180 | #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ | |
1181 | #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ | |
1182 | #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ | |
1183 | #define COMMENT 0x10 /* bit 4 set: file comment present */ | |
1184 | #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ | |
1185 | #define RESERVED 0xC0 /* bit 6,7: reserved */ | |
1186 | ||
1187 | /* | |
1188 | * Do the uncompression! | |
1189 | */ | |
1190 | static int INIT gunzip(void) | |
1191 | { | |
1192 | uch flags; | |
1193 | unsigned char magic[2]; /* magic header */ | |
1194 | char method; | |
1195 | ulg orig_crc = 0; /* original crc */ | |
1196 | ulg orig_len = 0; /* original uncompressed length */ | |
1197 | int res; | |
1198 | ||
1199 | magic[0] = NEXTBYTE(); | |
1200 | magic[1] = NEXTBYTE(); | |
1201 | method = NEXTBYTE(); | |
1202 | ||
1203 | if (magic[0] != 037 || | |
1204 | ((magic[1] != 0213) && (magic[1] != 0236))) { | |
1205 | error("bad gzip magic numbers"); | |
1206 | return -1; | |
1207 | } | |
1208 | ||
1209 | /* We only support method #8, DEFLATED */ | |
1210 | if (method != 8) { | |
1211 | error("internal error, invalid method"); | |
1212 | return -1; | |
1213 | } | |
1214 | ||
1215 | flags = (uch)get_byte(); | |
1216 | if ((flags & ENCRYPTED) != 0) { | |
1217 | error("Input is encrypted"); | |
1218 | return -1; | |
1219 | } | |
1220 | if ((flags & CONTINUATION) != 0) { | |
1221 | error("Multi part input"); | |
1222 | return -1; | |
1223 | } | |
1224 | if ((flags & RESERVED) != 0) { | |
1225 | error("Input has invalid flags"); | |
1226 | return -1; | |
1227 | } | |
1228 | NEXTBYTE(); /* Get timestamp */ | |
1229 | NEXTBYTE(); | |
1230 | NEXTBYTE(); | |
1231 | NEXTBYTE(); | |
1232 | ||
1233 | (void)NEXTBYTE(); /* Ignore extra flags for the moment */ | |
1234 | (void)NEXTBYTE(); /* Ignore OS type for the moment */ | |
1235 | ||
1236 | if ((flags & EXTRA_FIELD) != 0) { | |
1237 | unsigned len = (unsigned)NEXTBYTE(); | |
1238 | len |= ((unsigned)NEXTBYTE())<<8; | |
1239 | while (len--) (void)NEXTBYTE(); | |
1240 | } | |
1241 | ||
1242 | /* Get original file name if it was truncated */ | |
1243 | if ((flags & ORIG_NAME) != 0) { | |
1244 | /* Discard the old name */ | |
1245 | while (NEXTBYTE() != 0) /* null */ ; | |
1246 | } | |
1247 | ||
1248 | /* Discard file comment if any */ | |
1249 | if ((flags & COMMENT) != 0) { | |
1250 | while (NEXTBYTE() != 0) /* null */ ; | |
1251 | } | |
1252 | ||
1253 | /* Decompress */ | |
1254 | if ((res = inflate())) { | |
1255 | switch (res) { | |
1256 | case 0: | |
1257 | break; | |
1258 | case 1: | |
1259 | error("invalid compressed format (err=1)"); | |
1260 | break; | |
1261 | case 2: | |
1262 | error("invalid compressed format (err=2)"); | |
1263 | break; | |
1264 | case 3: | |
1265 | error("out of memory"); | |
1266 | break; | |
1267 | case 4: | |
1268 | error("out of input data"); | |
1269 | break; | |
1270 | default: | |
1271 | error("invalid compressed format (other)"); | |
1272 | } | |
1273 | return -1; | |
1274 | } | |
1275 | ||
1276 | /* Get the crc and original length */ | |
1277 | /* crc32 (see algorithm.doc) | |
1278 | * uncompressed input size modulo 2^32 | |
1279 | */ | |
1280 | orig_crc = (ulg) NEXTBYTE(); | |
1281 | orig_crc |= (ulg) NEXTBYTE() << 8; | |
1282 | orig_crc |= (ulg) NEXTBYTE() << 16; | |
1283 | orig_crc |= (ulg) NEXTBYTE() << 24; | |
1284 | ||
1285 | orig_len = (ulg) NEXTBYTE(); | |
1286 | orig_len |= (ulg) NEXTBYTE() << 8; | |
1287 | orig_len |= (ulg) NEXTBYTE() << 16; | |
1288 | orig_len |= (ulg) NEXTBYTE() << 24; | |
1289 | ||
1290 | /* Validate decompression */ | |
1291 | if (orig_crc != CRC_VALUE) { | |
1292 | error("crc error"); | |
1293 | return -1; | |
1294 | } | |
1295 | if (orig_len != bytes_out) { | |
1296 | error("length error"); | |
1297 | return -1; | |
1298 | } | |
1299 | return 0; | |
1300 | ||
1301 | underrun: /* NEXTBYTE() goto's here if needed */ | |
1302 | error("out of input data"); | |
1303 | return -1; | |
1304 | } | |
1305 | ||
1306 |