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