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@fluxnic.net>, 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 #ifdef NO_INFLATE_MALLOC
107 #include <linux/slab.h>
108 #endif
109
110 #ifdef RCSID
111 static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #";
112 #endif
113
114 #ifndef STATIC
115
116 #if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H)
117 # include <sys/types.h>
118 # include <stdlib.h>
119 #endif
120
121 #include "gzip.h"
122 #define STATIC
123 #endif /* !STATIC */
124
125 #ifndef INIT
126 #define INIT
127 #endif
128
129 #define slide window
130
131 /* Huffman code lookup table entry--this entry is four bytes for machines
132 that have 16-bit pointers (e.g. PC's in the small or medium model).
133 Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
134 means that v is a literal, 16 < e < 32 means that v is a pointer to
135 the next table, which codes e - 16 bits, and lastly e == 99 indicates
136 an unused code. If a code with e == 99 is looked up, this implies an
137 error in the data. */
138 struct huft {
139 uch e; /* number of extra bits or operation */
140 uch b; /* number of bits in this code or subcode */
141 union {
142 ush n; /* literal, length base, or distance base */
143 struct huft *t; /* pointer to next level of table */
144 } v;
145 };
146
147
148 /* Function prototypes */
149 STATIC int INIT huft_build OF((unsigned *, unsigned, unsigned,
150 const ush *, const ush *, struct huft **, int *));
151 STATIC int INIT huft_free OF((struct huft *));
152 STATIC int INIT inflate_codes OF((struct huft *, struct huft *, int, int));
153 STATIC int INIT inflate_stored OF((void));
154 STATIC int INIT inflate_fixed OF((void));
155 STATIC int INIT inflate_dynamic OF((void));
156 STATIC int INIT inflate_block OF((int *));
157 STATIC int INIT inflate OF((void));
158
159
160 /* The inflate algorithm uses a sliding 32 K byte window on the uncompressed
161 stream to find repeated byte strings. This is implemented here as a
162 circular buffer. The index is updated simply by incrementing and then
163 ANDing with 0x7fff (32K-1). */
164 /* It is left to other modules to supply the 32 K area. It is assumed
165 to be usable as if it were declared "uch slide[32768];" or as just
166 "uch *slide;" and then malloc'ed in the latter case. The definition
167 must be in unzip.h, included above. */
168 /* unsigned wp; current position in slide */
169 #define wp outcnt
170 #define flush_output(w) (wp=(w),flush_window())
171
172 /* Tables for deflate from PKZIP's appnote.txt. */
173 static const unsigned border[] = { /* Order of the bit length code lengths */
174 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
175 static const ush cplens[] = { /* Copy lengths for literal codes 257..285 */
176 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
177 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
178 /* note: see note #13 above about the 258 in this list. */
179 static const ush cplext[] = { /* Extra bits for literal codes 257..285 */
180 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
181 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */
182 static const ush cpdist[] = { /* Copy offsets for distance codes 0..29 */
183 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
184 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
185 8193, 12289, 16385, 24577};
186 static const ush cpdext[] = { /* Extra bits for distance codes */
187 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
188 7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
189 12, 12, 13, 13};
190
191
192
193 /* Macros for inflate() bit peeking and grabbing.
194 The usage is:
195
196 NEEDBITS(j)
197 x = b & mask_bits[j];
198 DUMPBITS(j)
199
200 where NEEDBITS makes sure that b has at least j bits in it, and
201 DUMPBITS removes the bits from b. The macros use the variable k
202 for the number of bits in b. Normally, b and k are register
203 variables for speed, and are initialized at the beginning of a
204 routine that uses these macros from a global bit buffer and count.
205
206 If we assume that EOB will be the longest code, then we will never
207 ask for bits with NEEDBITS that are beyond the end of the stream.
208 So, NEEDBITS should not read any more bytes than are needed to
209 meet the request. Then no bytes need to be "returned" to the buffer
210 at the end of the last block.
211
212 However, this assumption is not true for fixed blocks--the EOB code
213 is 7 bits, but the other literal/length codes can be 8 or 9 bits.
214 (The EOB code is shorter than other codes because fixed blocks are
215 generally short. So, while a block always has an EOB, many other
216 literal/length codes have a significantly lower probability of
217 showing up at all.) However, by making the first table have a
218 lookup of seven bits, the EOB code will be found in that first
219 lookup, and so will not require that too many bits be pulled from
220 the stream.
221 */
222
223 STATIC ulg bb; /* bit buffer */
224 STATIC unsigned bk; /* bits in bit buffer */
225
226 STATIC const ush mask_bits[] = {
227 0x0000,
228 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
229 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
230 };
231
232 #define NEXTBYTE() ({ int v = get_byte(); if (v < 0) goto underrun; (uch)v; })
233 #define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}}
234 #define DUMPBITS(n) {b>>=(n);k-=(n);}
235
236 #ifndef NO_INFLATE_MALLOC
237 /* A trivial malloc implementation, adapted from
238 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
239 */
240
241 static unsigned long malloc_ptr;
242 static int malloc_count;
243
malloc(int size)244 static void *malloc(int size)
245 {
246 void *p;
247
248 if (size < 0)
249 error("Malloc error");
250 if (!malloc_ptr)
251 malloc_ptr = free_mem_ptr;
252
253 malloc_ptr = (malloc_ptr + 3) & ~3; /* Align */
254
255 p = (void *)malloc_ptr;
256 malloc_ptr += size;
257
258 if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr)
259 error("Out of memory");
260
261 malloc_count++;
262 return p;
263 }
264
free(void * where)265 static void free(void *where)
266 {
267 malloc_count--;
268 if (!malloc_count)
269 malloc_ptr = free_mem_ptr;
270 }
271 #else
272 #define malloc(a) kmalloc(a, GFP_KERNEL)
273 #define free(a) kfree(a)
274 #endif
275
276 /*
277 Huffman code decoding is performed using a multi-level table lookup.
278 The fastest way to decode is to simply build a lookup table whose
279 size is determined by the longest code. However, the time it takes
280 to build this table can also be a factor if the data being decoded
281 is not very long. The most common codes are necessarily the
282 shortest codes, so those codes dominate the decoding time, and hence
283 the speed. The idea is you can have a shorter table that decodes the
284 shorter, more probable codes, and then point to subsidiary tables for
285 the longer codes. The time it costs to decode the longer codes is
286 then traded against the time it takes to make longer tables.
287
288 This results of this trade are in the variables lbits and dbits
289 below. lbits is the number of bits the first level table for literal/
290 length codes can decode in one step, and dbits is the same thing for
291 the distance codes. Subsequent tables are also less than or equal to
292 those sizes. These values may be adjusted either when all of the
293 codes are shorter than that, in which case the longest code length in
294 bits is used, or when the shortest code is *longer* than the requested
295 table size, in which case the length of the shortest code in bits is
296 used.
297
298 There are two different values for the two tables, since they code a
299 different number of possibilities each. The literal/length table
300 codes 286 possible values, or in a flat code, a little over eight
301 bits. The distance table codes 30 possible values, or a little less
302 than five bits, flat. The optimum values for speed end up being
303 about one bit more than those, so lbits is 8+1 and dbits is 5+1.
304 The optimum values may differ though from machine to machine, and
305 possibly even between compilers. Your mileage may vary.
306 */
307
308
309 STATIC const int lbits = 9; /* bits in base literal/length lookup table */
310 STATIC const int dbits = 6; /* bits in base distance lookup table */
311
312
313 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
314 #define BMAX 16 /* maximum bit length of any code (16 for explode) */
315 #define N_MAX 288 /* maximum number of codes in any set */
316
317
318 STATIC unsigned hufts; /* track memory usage */
319
320
huft_build(unsigned * b,unsigned n,unsigned s,const ush * d,const ush * e,struct huft ** t,int * m)321 STATIC int INIT huft_build(
322 unsigned *b, /* code lengths in bits (all assumed <= BMAX) */
323 unsigned n, /* number of codes (assumed <= N_MAX) */
324 unsigned s, /* number of simple-valued codes (0..s-1) */
325 const ush *d, /* list of base values for non-simple codes */
326 const ush *e, /* list of extra bits for non-simple codes */
327 struct huft **t, /* result: starting table */
328 int *m /* maximum lookup bits, returns actual */
329 )
330 /* Given a list of code lengths and a maximum table size, make a set of
331 tables to decode that set of codes. Return zero on success, one if
332 the given code set is incomplete (the tables are still built in this
333 case), two if the input is invalid (all zero length codes or an
334 oversubscribed set of lengths), and three if not enough memory. */
335 {
336 unsigned a; /* counter for codes of length k */
337 unsigned f; /* i repeats in table every f entries */
338 int g; /* maximum code length */
339 int h; /* table level */
340 register unsigned i; /* counter, current code */
341 register unsigned j; /* counter */
342 register int k; /* number of bits in current code */
343 int l; /* bits per table (returned in m) */
344 register unsigned *p; /* pointer into c[], b[], or v[] */
345 register struct huft *q; /* points to current table */
346 struct huft r; /* table entry for structure assignment */
347 register int w; /* bits before this table == (l * h) */
348 unsigned *xp; /* pointer into x */
349 int y; /* number of dummy codes added */
350 unsigned z; /* number of entries in current table */
351 struct {
352 unsigned c[BMAX+1]; /* bit length count table */
353 struct huft *u[BMAX]; /* table stack */
354 unsigned v[N_MAX]; /* values in order of bit length */
355 unsigned x[BMAX+1]; /* bit offsets, then code stack */
356 } *stk;
357 unsigned *c, *v, *x;
358 struct huft **u;
359 int ret;
360
361 DEBG("huft1 ");
362
363 stk = malloc(sizeof(*stk));
364 if (stk == NULL)
365 return 3; /* out of memory */
366
367 c = stk->c;
368 v = stk->v;
369 x = stk->x;
370 u = stk->u;
371
372 /* Generate counts for each bit length */
373 memzero(stk->c, sizeof(stk->c));
374 p = b; i = n;
375 do {
376 Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"),
377 n-i, *p));
378 c[*p]++; /* assume all entries <= BMAX */
379 p++; /* Can't combine with above line (Solaris bug) */
380 } while (--i);
381 if (c[0] == n) /* null input--all zero length codes */
382 {
383 *t = (struct huft *)NULL;
384 *m = 0;
385 ret = 2;
386 goto out;
387 }
388
389 DEBG("huft2 ");
390
391 /* Find minimum and maximum length, bound *m by those */
392 l = *m;
393 for (j = 1; j <= BMAX; j++)
394 if (c[j])
395 break;
396 k = j; /* minimum code length */
397 if ((unsigned)l < j)
398 l = j;
399 for (i = BMAX; i; i--)
400 if (c[i])
401 break;
402 g = i; /* maximum code length */
403 if ((unsigned)l > i)
404 l = i;
405 *m = l;
406
407 DEBG("huft3 ");
408
409 /* Adjust last length count to fill out codes, if needed */
410 for (y = 1 << j; j < i; j++, y <<= 1)
411 if ((y -= c[j]) < 0) {
412 ret = 2; /* bad input: more codes than bits */
413 goto out;
414 }
415 if ((y -= c[i]) < 0) {
416 ret = 2;
417 goto out;
418 }
419 c[i] += y;
420
421 DEBG("huft4 ");
422
423 /* Generate starting offsets into the value table for each length */
424 x[1] = j = 0;
425 p = c + 1; xp = x + 2;
426 while (--i) { /* note that i == g from above */
427 *xp++ = (j += *p++);
428 }
429
430 DEBG("huft5 ");
431
432 /* Make a table of values in order of bit lengths */
433 p = b; i = 0;
434 do {
435 if ((j = *p++) != 0)
436 v[x[j]++] = i;
437 } while (++i < n);
438 n = x[g]; /* set n to length of v */
439
440 DEBG("h6 ");
441
442 /* Generate the Huffman codes and for each, make the table entries */
443 x[0] = i = 0; /* first Huffman code is zero */
444 p = v; /* grab values in bit order */
445 h = -1; /* no tables yet--level -1 */
446 w = -l; /* bits decoded == (l * h) */
447 u[0] = (struct huft *)NULL; /* just to keep compilers happy */
448 q = (struct huft *)NULL; /* ditto */
449 z = 0; /* ditto */
450 DEBG("h6a ");
451
452 /* go through the bit lengths (k already is bits in shortest code) */
453 for (; k <= g; k++)
454 {
455 DEBG("h6b ");
456 a = c[k];
457 while (a--)
458 {
459 DEBG("h6b1 ");
460 /* here i is the Huffman code of length k bits for value *p */
461 /* make tables up to required level */
462 while (k > w + l)
463 {
464 DEBG1("1 ");
465 h++;
466 w += l; /* previous table always l bits */
467
468 /* compute minimum size table less than or equal to l bits */
469 z = (z = g - w) > (unsigned)l ? l : z; /* upper limit on table size */
470 if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */
471 { /* too few codes for k-w bit table */
472 DEBG1("2 ");
473 f -= a + 1; /* deduct codes from patterns left */
474 xp = c + k;
475 if (j < z)
476 while (++j < z) /* try smaller tables up to z bits */
477 {
478 if ((f <<= 1) <= *++xp)
479 break; /* enough codes to use up j bits */
480 f -= *xp; /* else deduct codes from patterns */
481 }
482 }
483 DEBG1("3 ");
484 z = 1 << j; /* table entries for j-bit table */
485
486 /* allocate and link in new table */
487 if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) ==
488 (struct huft *)NULL)
489 {
490 if (h)
491 huft_free(u[0]);
492 ret = 3; /* not enough memory */
493 goto out;
494 }
495 DEBG1("4 ");
496 hufts += z + 1; /* track memory usage */
497 *t = q + 1; /* link to list for huft_free() */
498 *(t = &(q->v.t)) = (struct huft *)NULL;
499 u[h] = ++q; /* table starts after link */
500
501 DEBG1("5 ");
502 /* connect to last table, if there is one */
503 if (h)
504 {
505 x[h] = i; /* save pattern for backing up */
506 r.b = (uch)l; /* bits to dump before this table */
507 r.e = (uch)(16 + j); /* bits in this table */
508 r.v.t = q; /* pointer to this table */
509 j = i >> (w - l); /* (get around Turbo C bug) */
510 u[h-1][j] = r; /* connect to last table */
511 }
512 DEBG1("6 ");
513 }
514 DEBG("h6c ");
515
516 /* set up table entry in r */
517 r.b = (uch)(k - w);
518 if (p >= v + n)
519 r.e = 99; /* out of values--invalid code */
520 else if (*p < s)
521 {
522 r.e = (uch)(*p < 256 ? 16 : 15); /* 256 is end-of-block code */
523 r.v.n = (ush)(*p); /* simple code is just the value */
524 p++; /* one compiler does not like *p++ */
525 }
526 else
527 {
528 r.e = (uch)e[*p - s]; /* non-simple--look up in lists */
529 r.v.n = d[*p++ - s];
530 }
531 DEBG("h6d ");
532
533 /* fill code-like entries with r */
534 f = 1 << (k - w);
535 for (j = i >> w; j < z; j += f)
536 q[j] = r;
537
538 /* backwards increment the k-bit code i */
539 for (j = 1 << (k - 1); i & j; j >>= 1)
540 i ^= j;
541 i ^= j;
542
543 /* backup over finished tables */
544 while ((i & ((1 << w) - 1)) != x[h])
545 {
546 h--; /* don't need to update q */
547 w -= l;
548 }
549 DEBG("h6e ");
550 }
551 DEBG("h6f ");
552 }
553
554 DEBG("huft7 ");
555
556 /* Return true (1) if we were given an incomplete table */
557 ret = y != 0 && g != 1;
558
559 out:
560 free(stk);
561 return ret;
562 }
563
564
565
huft_free(struct huft * t)566 STATIC int INIT huft_free(
567 struct huft *t /* table to free */
568 )
569 /* Free the malloc'ed tables built by huft_build(), which makes a linked
570 list of the tables it made, with the links in a dummy first entry of
571 each table. */
572 {
573 register struct huft *p, *q;
574
575
576 /* Go through linked list, freeing from the malloced (t[-1]) address. */
577 p = t;
578 while (p != (struct huft *)NULL)
579 {
580 q = (--p)->v.t;
581 free((char*)p);
582 p = q;
583 }
584 return 0;
585 }
586
587
inflate_codes(struct huft * tl,struct huft * td,int bl,int bd)588 STATIC int INIT inflate_codes(
589 struct huft *tl, /* literal/length decoder tables */
590 struct huft *td, /* distance decoder tables */
591 int bl, /* number of bits decoded by tl[] */
592 int bd /* number of bits decoded by td[] */
593 )
594 /* inflate (decompress) the codes in a deflated (compressed) block.
595 Return an error code or zero if it all goes ok. */
596 {
597 register unsigned e; /* table entry flag/number of extra bits */
598 unsigned n, d; /* length and index for copy */
599 unsigned w; /* current window position */
600 struct huft *t; /* pointer to table entry */
601 unsigned ml, md; /* masks for bl and bd bits */
602 register ulg b; /* bit buffer */
603 register unsigned k; /* number of bits in bit buffer */
604
605
606 /* make local copies of globals */
607 b = bb; /* initialize bit buffer */
608 k = bk;
609 w = wp; /* initialize window position */
610
611 /* inflate the coded data */
612 ml = mask_bits[bl]; /* precompute masks for speed */
613 md = mask_bits[bd];
614 for (;;) /* do until end of block */
615 {
616 NEEDBITS((unsigned)bl)
617 if ((e = (t = tl + ((unsigned)b & ml))->e) > 16)
618 do {
619 if (e == 99)
620 return 1;
621 DUMPBITS(t->b)
622 e -= 16;
623 NEEDBITS(e)
624 } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16);
625 DUMPBITS(t->b)
626 if (e == 16) /* then it's a literal */
627 {
628 slide[w++] = (uch)t->v.n;
629 Tracevv((stderr, "%c", slide[w-1]));
630 if (w == WSIZE)
631 {
632 flush_output(w);
633 w = 0;
634 }
635 }
636 else /* it's an EOB or a length */
637 {
638 /* exit if end of block */
639 if (e == 15)
640 break;
641
642 /* get length of block to copy */
643 NEEDBITS(e)
644 n = t->v.n + ((unsigned)b & mask_bits[e]);
645 DUMPBITS(e);
646
647 /* decode distance of block to copy */
648 NEEDBITS((unsigned)bd)
649 if ((e = (t = td + ((unsigned)b & md))->e) > 16)
650 do {
651 if (e == 99)
652 return 1;
653 DUMPBITS(t->b)
654 e -= 16;
655 NEEDBITS(e)
656 } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16);
657 DUMPBITS(t->b)
658 NEEDBITS(e)
659 d = w - t->v.n - ((unsigned)b & mask_bits[e]);
660 DUMPBITS(e)
661 Tracevv((stderr,"\\[%d,%d]", w-d, n));
662
663 /* do the copy */
664 do {
665 n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e);
666 #if !defined(NOMEMCPY) && !defined(DEBUG)
667 if (w - d >= e) /* (this test assumes unsigned comparison) */
668 {
669 memcpy(slide + w, slide + d, e);
670 w += e;
671 d += e;
672 }
673 else /* do it slow to avoid memcpy() overlap */
674 #endif /* !NOMEMCPY */
675 do {
676 slide[w++] = slide[d++];
677 Tracevv((stderr, "%c", slide[w-1]));
678 } while (--e);
679 if (w == WSIZE)
680 {
681 flush_output(w);
682 w = 0;
683 }
684 } while (n);
685 }
686 }
687
688
689 /* restore the globals from the locals */
690 wp = w; /* restore global window pointer */
691 bb = b; /* restore global bit buffer */
692 bk = k;
693
694 /* done */
695 return 0;
696
697 underrun:
698 return 4; /* Input underrun */
699 }
700
701
702
inflate_stored(void)703 STATIC int INIT inflate_stored(void)
704 /* "decompress" an inflated type 0 (stored) block. */
705 {
706 unsigned n; /* number of bytes in block */
707 unsigned w; /* current window position */
708 register ulg b; /* bit buffer */
709 register unsigned k; /* number of bits in bit buffer */
710
711 DEBG("<stor");
712
713 /* make local copies of globals */
714 b = bb; /* initialize bit buffer */
715 k = bk;
716 w = wp; /* initialize window position */
717
718
719 /* go to byte boundary */
720 n = k & 7;
721 DUMPBITS(n);
722
723
724 /* get the length and its complement */
725 NEEDBITS(16)
726 n = ((unsigned)b & 0xffff);
727 DUMPBITS(16)
728 NEEDBITS(16)
729 if (n != (unsigned)((~b) & 0xffff))
730 return 1; /* error in compressed data */
731 DUMPBITS(16)
732
733
734 /* read and output the compressed data */
735 while (n--)
736 {
737 NEEDBITS(8)
738 slide[w++] = (uch)b;
739 if (w == WSIZE)
740 {
741 flush_output(w);
742 w = 0;
743 }
744 DUMPBITS(8)
745 }
746
747
748 /* restore the globals from the locals */
749 wp = w; /* restore global window pointer */
750 bb = b; /* restore global bit buffer */
751 bk = k;
752
753 DEBG(">");
754 return 0;
755
756 underrun:
757 return 4; /* Input underrun */
758 }
759
760
761 /*
762 * We use `noinline' here to prevent gcc-3.5 from using too much stack space
763 */
inflate_fixed(void)764 STATIC int noinline INIT inflate_fixed(void)
765 /* decompress an inflated type 1 (fixed Huffman codes) block. We should
766 either replace this with a custom decoder, or at least precompute the
767 Huffman tables. */
768 {
769 int i; /* temporary variable */
770 struct huft *tl; /* literal/length code table */
771 struct huft *td; /* distance code table */
772 int bl; /* lookup bits for tl */
773 int bd; /* lookup bits for td */
774 unsigned *l; /* length list for huft_build */
775
776 DEBG("<fix");
777
778 l = malloc(sizeof(*l) * 288);
779 if (l == NULL)
780 return 3; /* out of memory */
781
782 /* set up literal table */
783 for (i = 0; i < 144; i++)
784 l[i] = 8;
785 for (; i < 256; i++)
786 l[i] = 9;
787 for (; i < 280; i++)
788 l[i] = 7;
789 for (; i < 288; i++) /* make a complete, but wrong code set */
790 l[i] = 8;
791 bl = 7;
792 if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
793 free(l);
794 return i;
795 }
796
797 /* set up distance table */
798 for (i = 0; i < 30; i++) /* make an incomplete code set */
799 l[i] = 5;
800 bd = 5;
801 if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1)
802 {
803 huft_free(tl);
804 free(l);
805
806 DEBG(">");
807 return i;
808 }
809
810
811 /* decompress until an end-of-block code */
812 if (inflate_codes(tl, td, bl, bd)) {
813 free(l);
814 return 1;
815 }
816
817 /* free the decoding tables, return */
818 free(l);
819 huft_free(tl);
820 huft_free(td);
821 return 0;
822 }
823
824
825 /*
826 * We use `noinline' here to prevent gcc-3.5 from using too much stack space
827 */
inflate_dynamic(void)828 STATIC int noinline INIT inflate_dynamic(void)
829 /* decompress an inflated type 2 (dynamic Huffman codes) block. */
830 {
831 int i; /* temporary variables */
832 unsigned j;
833 unsigned l; /* last length */
834 unsigned m; /* mask for bit lengths table */
835 unsigned n; /* number of lengths to get */
836 struct huft *tl; /* literal/length code table */
837 struct huft *td; /* distance code table */
838 int bl; /* lookup bits for tl */
839 int bd; /* lookup bits for td */
840 unsigned nb; /* number of bit length codes */
841 unsigned nl; /* number of literal/length codes */
842 unsigned nd; /* number of distance codes */
843 unsigned *ll; /* literal/length and distance code lengths */
844 register ulg b; /* bit buffer */
845 register unsigned k; /* number of bits in bit buffer */
846 int ret;
847
848 DEBG("<dyn");
849
850 #ifdef PKZIP_BUG_WORKAROUND
851 ll = malloc(sizeof(*ll) * (288+32)); /* literal/length and distance code lengths */
852 #else
853 ll = malloc(sizeof(*ll) * (286+30)); /* literal/length and distance code lengths */
854 #endif
855
856 if (ll == NULL)
857 return 1;
858
859 /* make local bit buffer */
860 b = bb;
861 k = bk;
862
863
864 /* read in table lengths */
865 NEEDBITS(5)
866 nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length codes */
867 DUMPBITS(5)
868 NEEDBITS(5)
869 nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */
870 DUMPBITS(5)
871 NEEDBITS(4)
872 nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */
873 DUMPBITS(4)
874 #ifdef PKZIP_BUG_WORKAROUND
875 if (nl > 288 || nd > 32)
876 #else
877 if (nl > 286 || nd > 30)
878 #endif
879 {
880 ret = 1; /* bad lengths */
881 goto out;
882 }
883
884 DEBG("dyn1 ");
885
886 /* read in bit-length-code lengths */
887 for (j = 0; j < nb; j++)
888 {
889 NEEDBITS(3)
890 ll[border[j]] = (unsigned)b & 7;
891 DUMPBITS(3)
892 }
893 for (; j < 19; j++)
894 ll[border[j]] = 0;
895
896 DEBG("dyn2 ");
897
898 /* build decoding table for trees--single level, 7 bit lookup */
899 bl = 7;
900 if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0)
901 {
902 if (i == 1)
903 huft_free(tl);
904 ret = i; /* incomplete code set */
905 goto out;
906 }
907
908 DEBG("dyn3 ");
909
910 /* read in literal and distance code lengths */
911 n = nl + nd;
912 m = mask_bits[bl];
913 i = l = 0;
914 while ((unsigned)i < n)
915 {
916 NEEDBITS((unsigned)bl)
917 j = (td = tl + ((unsigned)b & m))->b;
918 DUMPBITS(j)
919 j = td->v.n;
920 if (j < 16) /* length of code in bits (0..15) */
921 ll[i++] = l = j; /* save last length in l */
922 else if (j == 16) /* repeat last length 3 to 6 times */
923 {
924 NEEDBITS(2)
925 j = 3 + ((unsigned)b & 3);
926 DUMPBITS(2)
927 if ((unsigned)i + j > n) {
928 ret = 1;
929 goto out;
930 }
931 while (j--)
932 ll[i++] = l;
933 }
934 else if (j == 17) /* 3 to 10 zero length codes */
935 {
936 NEEDBITS(3)
937 j = 3 + ((unsigned)b & 7);
938 DUMPBITS(3)
939 if ((unsigned)i + j > n) {
940 ret = 1;
941 goto out;
942 }
943 while (j--)
944 ll[i++] = 0;
945 l = 0;
946 }
947 else /* j == 18: 11 to 138 zero length codes */
948 {
949 NEEDBITS(7)
950 j = 11 + ((unsigned)b & 0x7f);
951 DUMPBITS(7)
952 if ((unsigned)i + j > n) {
953 ret = 1;
954 goto out;
955 }
956 while (j--)
957 ll[i++] = 0;
958 l = 0;
959 }
960 }
961
962 DEBG("dyn4 ");
963
964 /* free decoding table for trees */
965 huft_free(tl);
966
967 DEBG("dyn5 ");
968
969 /* restore the global bit buffer */
970 bb = b;
971 bk = k;
972
973 DEBG("dyn5a ");
974
975 /* build the decoding tables for literal/length and distance codes */
976 bl = lbits;
977 if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0)
978 {
979 DEBG("dyn5b ");
980 if (i == 1) {
981 error("incomplete literal tree");
982 huft_free(tl);
983 }
984 ret = i; /* incomplete code set */
985 goto out;
986 }
987 DEBG("dyn5c ");
988 bd = dbits;
989 if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0)
990 {
991 DEBG("dyn5d ");
992 if (i == 1) {
993 error("incomplete distance tree");
994 #ifdef PKZIP_BUG_WORKAROUND
995 i = 0;
996 }
997 #else
998 huft_free(td);
999 }
1000 huft_free(tl);
1001 ret = i; /* incomplete code set */
1002 goto out;
1003 #endif
1004 }
1005
1006 DEBG("dyn6 ");
1007
1008 /* decompress until an end-of-block code */
1009 if (inflate_codes(tl, td, bl, bd)) {
1010 ret = 1;
1011 goto out;
1012 }
1013
1014 DEBG("dyn7 ");
1015
1016 /* free the decoding tables, return */
1017 huft_free(tl);
1018 huft_free(td);
1019
1020 DEBG(">");
1021 ret = 0;
1022 out:
1023 free(ll);
1024 return ret;
1025
1026 underrun:
1027 ret = 4; /* Input underrun */
1028 goto out;
1029 }
1030
1031
1032
inflate_block(int * e)1033 STATIC int INIT inflate_block(
1034 int *e /* last block flag */
1035 )
1036 /* decompress an inflated block */
1037 {
1038 unsigned t; /* block type */
1039 register ulg b; /* bit buffer */
1040 register unsigned k; /* number of bits in bit buffer */
1041
1042 DEBG("<blk");
1043
1044 /* make local bit buffer */
1045 b = bb;
1046 k = bk;
1047
1048
1049 /* read in last block bit */
1050 NEEDBITS(1)
1051 *e = (int)b & 1;
1052 DUMPBITS(1)
1053
1054
1055 /* read in block type */
1056 NEEDBITS(2)
1057 t = (unsigned)b & 3;
1058 DUMPBITS(2)
1059
1060
1061 /* restore the global bit buffer */
1062 bb = b;
1063 bk = k;
1064
1065 /* inflate that block type */
1066 if (t == 2)
1067 return inflate_dynamic();
1068 if (t == 0)
1069 return inflate_stored();
1070 if (t == 1)
1071 return inflate_fixed();
1072
1073 DEBG(">");
1074
1075 /* bad block type */
1076 return 2;
1077
1078 underrun:
1079 return 4; /* Input underrun */
1080 }
1081
1082
1083
inflate(void)1084 STATIC int INIT inflate(void)
1085 /* decompress an inflated entry */
1086 {
1087 int e; /* last block flag */
1088 int r; /* result code */
1089 unsigned h; /* maximum struct huft's malloc'ed */
1090
1091 /* initialize window, bit buffer */
1092 wp = 0;
1093 bk = 0;
1094 bb = 0;
1095
1096
1097 /* decompress until the last block */
1098 h = 0;
1099 do {
1100 hufts = 0;
1101 #ifdef ARCH_HAS_DECOMP_WDOG
1102 arch_decomp_wdog();
1103 #endif
1104 r = inflate_block(&e);
1105 if (r)
1106 return r;
1107 if (hufts > h)
1108 h = hufts;
1109 } while (!e);
1110
1111 /* Undo too much lookahead. The next read will be byte aligned so we
1112 * can discard unused bits in the last meaningful byte.
1113 */
1114 while (bk >= 8) {
1115 bk -= 8;
1116 inptr--;
1117 }
1118
1119 /* flush out slide */
1120 flush_output(wp);
1121
1122
1123 /* return success */
1124 #ifdef DEBUG
1125 fprintf(stderr, "<%u> ", h);
1126 #endif /* DEBUG */
1127 return 0;
1128 }
1129
1130 /**********************************************************************
1131 *
1132 * The following are support routines for inflate.c
1133 *
1134 **********************************************************************/
1135
1136 static ulg crc_32_tab[256];
1137 static ulg crc; /* initialized in makecrc() so it'll reside in bss */
1138 #define CRC_VALUE (crc ^ 0xffffffffUL)
1139
1140 /*
1141 * Code to compute the CRC-32 table. Borrowed from
1142 * gzip-1.0.3/makecrc.c.
1143 */
1144
1145 static void INIT
makecrc(void)1146 makecrc(void)
1147 {
1148 /* Not copyrighted 1990 Mark Adler */
1149
1150 unsigned long c; /* crc shift register */
1151 unsigned long e; /* polynomial exclusive-or pattern */
1152 int i; /* counter for all possible eight bit values */
1153 int k; /* byte being shifted into crc apparatus */
1154
1155 /* terms of polynomial defining this crc (except x^32): */
1156 static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
1157
1158 /* Make exclusive-or pattern from polynomial */
1159 e = 0;
1160 for (i = 0; i < sizeof(p)/sizeof(int); i++)
1161 e |= 1L << (31 - p[i]);
1162
1163 crc_32_tab[0] = 0;
1164
1165 for (i = 1; i < 256; i++)
1166 {
1167 c = 0;
1168 for (k = i | 256; k != 1; k >>= 1)
1169 {
1170 c = c & 1 ? (c >> 1) ^ e : c >> 1;
1171 if (k & 1)
1172 c ^= e;
1173 }
1174 crc_32_tab[i] = c;
1175 }
1176
1177 /* this is initialized here so this code could reside in ROM */
1178 crc = (ulg)0xffffffffUL; /* shift register contents */
1179 }
1180
1181 /* gzip flag byte */
1182 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
1183 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
1184 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
1185 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
1186 #define COMMENT 0x10 /* bit 4 set: file comment present */
1187 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
1188 #define RESERVED 0xC0 /* bit 6,7: reserved */
1189
1190 /*
1191 * Do the uncompression!
1192 */
gunzip(void)1193 static int INIT gunzip(void)
1194 {
1195 uch flags;
1196 unsigned char magic[2]; /* magic header */
1197 char method;
1198 ulg orig_crc = 0; /* original crc */
1199 ulg orig_len = 0; /* original uncompressed length */
1200 int res;
1201
1202 magic[0] = NEXTBYTE();
1203 magic[1] = NEXTBYTE();
1204 method = NEXTBYTE();
1205
1206 if (magic[0] != 037 ||
1207 ((magic[1] != 0213) && (magic[1] != 0236))) {
1208 error("bad gzip magic numbers");
1209 return -1;
1210 }
1211
1212 /* We only support method #8, DEFLATED */
1213 if (method != 8) {
1214 error("internal error, invalid method");
1215 return -1;
1216 }
1217
1218 flags = (uch)get_byte();
1219 if ((flags & ENCRYPTED) != 0) {
1220 error("Input is encrypted");
1221 return -1;
1222 }
1223 if ((flags & CONTINUATION) != 0) {
1224 error("Multi part input");
1225 return -1;
1226 }
1227 if ((flags & RESERVED) != 0) {
1228 error("Input has invalid flags");
1229 return -1;
1230 }
1231 NEXTBYTE(); /* Get timestamp */
1232 NEXTBYTE();
1233 NEXTBYTE();
1234 NEXTBYTE();
1235
1236 (void)NEXTBYTE(); /* Ignore extra flags for the moment */
1237 (void)NEXTBYTE(); /* Ignore OS type for the moment */
1238
1239 if ((flags & EXTRA_FIELD) != 0) {
1240 unsigned len = (unsigned)NEXTBYTE();
1241 len |= ((unsigned)NEXTBYTE())<<8;
1242 while (len--) (void)NEXTBYTE();
1243 }
1244
1245 /* Get original file name if it was truncated */
1246 if ((flags & ORIG_NAME) != 0) {
1247 /* Discard the old name */
1248 while (NEXTBYTE() != 0) /* null */ ;
1249 }
1250
1251 /* Discard file comment if any */
1252 if ((flags & COMMENT) != 0) {
1253 while (NEXTBYTE() != 0) /* null */ ;
1254 }
1255
1256 /* Decompress */
1257 if ((res = inflate())) {
1258 switch (res) {
1259 case 0:
1260 break;
1261 case 1:
1262 error("invalid compressed format (err=1)");
1263 break;
1264 case 2:
1265 error("invalid compressed format (err=2)");
1266 break;
1267 case 3:
1268 error("out of memory");
1269 break;
1270 case 4:
1271 error("out of input data");
1272 break;
1273 default:
1274 error("invalid compressed format (other)");
1275 }
1276 return -1;
1277 }
1278
1279 /* Get the crc and original length */
1280 /* crc32 (see algorithm.doc)
1281 * uncompressed input size modulo 2^32
1282 */
1283 orig_crc = (ulg) NEXTBYTE();
1284 orig_crc |= (ulg) NEXTBYTE() << 8;
1285 orig_crc |= (ulg) NEXTBYTE() << 16;
1286 orig_crc |= (ulg) NEXTBYTE() << 24;
1287
1288 orig_len = (ulg) NEXTBYTE();
1289 orig_len |= (ulg) NEXTBYTE() << 8;
1290 orig_len |= (ulg) NEXTBYTE() << 16;
1291 orig_len |= (ulg) NEXTBYTE() << 24;
1292
1293 /* Validate decompression */
1294 if (orig_crc != CRC_VALUE) {
1295 error("crc error");
1296 return -1;
1297 }
1298 if (orig_len != bytes_out) {
1299 error("length error");
1300 return -1;
1301 }
1302 return 0;
1303
1304 underrun: /* NEXTBYTE() goto's here if needed */
1305 error("out of input data");
1306 return -1;
1307 }
1308
1309
1310