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
106 #ifdef RCSID
107 static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #";
108 #endif
109
110 #ifndef STATIC
111
112 #if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H)
113 # include <sys/types.h>
114 # include <stdlib.h>
115 #endif
116
117 #include "gzip.h"
118 #define STATIC
119 #endif /* !STATIC */
120
121 #ifndef INIT
122 #define INIT
123 #define INITDATA
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 INITDATA bb; /* bit buffer */
221 STATIC unsigned INITDATA 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
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 INITDATA malloc_ptr;
239 static int INITDATA malloc_count;
240
malloc(int size)241 static void *INIT 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
free(void * where)262 static void INIT 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
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 INITDATA hufts; /* track memory usage */
316
317
huft_build(unsigned * b,unsigned n,unsigned s,const ush * d,const ush * e,struct huft ** t,int * m)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 */
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 */
344 register int w; /* bits before this table == (l * h) */
345 unsigned *xp; /* pointer into x */
346 int y; /* number of dummy codes added */
347 unsigned z; /* number of entries in current table */
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;
357
358 DEBG("huft1 ");
359
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
369 /* Generate counts for each bit length */
370 memzero(stk->c, sizeof(stk->c));
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;
382 ret = 2;
383 goto out;
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)
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 }
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);
435 n = x[g]; /* set n to length of v */
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;
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 }
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]);
489 ret = 3; /* not enough memory */
490 goto out;
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 */
554 ret = y != 0 && g != 1;
555
556 out:
557 free(stk);
558 return ret;
559 }
560
561
562
huft_free(struct huft * t)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
inflate_codes(struct huft * tl,struct huft * td,int bl,int bd)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
inflate_stored(void)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 */
inflate_fixed(void)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 */
771 unsigned *l; /* length list for huft_build */
772
773 DEBG("<fix");
774
775 l = malloc(sizeof(*l) * 288);
776 if (l == NULL)
777 return 3; /* out of memory */
778
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;
789 if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
790 free(l);
791 return i;
792 }
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);
801 free(l);
802
803 DEBG(">");
804 return i;
805 }
806
807
808 /* decompress until an end-of-block code */
809 if (inflate_codes(tl, td, bl, bd)) {
810 free(l);
811 return 1;
812 }
813
814 /* free the decoding tables, return */
815 free(l);
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 */
inflate_dynamic(void)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 */
840 unsigned *ll; /* literal/length and distance code lengths */
841 register ulg b; /* bit buffer */
842 register unsigned k; /* number of bits in bit buffer */
843 int ret;
844
845 DEBG("<dyn");
846
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
853 if (ll == NULL)
854 return 1;
855
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
876 {
877 ret = 1; /* bad lengths */
878 goto out;
879 }
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);
901 ret = i; /* incomplete code set */
902 goto out;
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)
924 if ((unsigned)i + j > n) {
925 ret = 1;
926 goto out;
927 }
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)
936 if ((unsigned)i + j > n) {
937 ret = 1;
938 goto out;
939 }
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)
949 if ((unsigned)i + j > n) {
950 ret = 1;
951 goto out;
952 }
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 }
981 ret = i; /* incomplete code set */
982 goto out;
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);
998 ret = i; /* incomplete code set */
999 goto out;
1000 #endif
1001 }
1002
1003 DEBG("dyn6 ");
1004
1005 /* decompress until an end-of-block code */
1006 if (inflate_codes(tl, td, bl, bd)) {
1007 ret = 1;
1008 goto out;
1009 }
1010
1011 DEBG("dyn7 ");
1012
1013 /* free the decoding tables, return */
1014 huft_free(tl);
1015 huft_free(td);
1016
1017 DEBG(">");
1018 ret = 0;
1019 out:
1020 free(ll);
1021 return ret;
1022
1023 underrun:
1024 ret = 4; /* Input underrun */
1025 goto out;
1026 }
1027
1028
1029
inflate_block(int * e)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
inflate(void)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 */
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;
1098 #ifdef ARCH_HAS_DECOMP_WDOG
1099 arch_decomp_wdog();
1100 #endif
1101 r = inflate_block(&e);
1102 if (r)
1103 return r;
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 INITDATA crc_32_tab[256];
1134 static ulg INITDATA 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
makecrc(void)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 */
gunzip(void)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