diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/inflate.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'lib/inflate.c')
-rw-r--r-- | lib/inflate.c | 1210 |
1 files changed, 1210 insertions, 0 deletions
diff --git a/lib/inflate.c b/lib/inflate.c new file mode 100644 index 000000000000..75e7d303c72e --- /dev/null +++ b/lib/inflate.c | |||
@@ -0,0 +1,1210 @@ | |||
1 | #define DEBG(x) | ||
2 | #define DEBG1(x) | ||
3 | /* inflate.c -- Not copyrighted 1992 by Mark Adler | ||
4 | version c10p1, 10 January 1993 */ | ||
5 | |||
6 | /* | ||
7 | * Adapted for booting Linux by Hannu Savolainen 1993 | ||
8 | * based on gzip-1.0.3 | ||
9 | * | ||
10 | * Nicolas Pitre <nico@cam.org>, 1999/04/14 : | ||
11 | * Little mods for all variable to reside either into rodata or bss segments | ||
12 | * by marking constant variables with 'const' and initializing all the others | ||
13 | * at run-time only. This allows for the kernel uncompressor to run | ||
14 | * directly from Flash or ROM memory on embedded systems. | ||
15 | */ | ||
16 | |||
17 | /* | ||
18 | Inflate deflated (PKZIP's method 8 compressed) data. The compression | ||
19 | method searches for as much of the current string of bytes (up to a | ||
20 | length of 258) in the previous 32 K bytes. If it doesn't find any | ||
21 | matches (of at least length 3), it codes the next byte. Otherwise, it | ||
22 | codes the length of the matched string and its distance backwards from | ||
23 | the current position. There is a single Huffman code that codes both | ||
24 | single bytes (called "literals") and match lengths. A second Huffman | ||
25 | code codes the distance information, which follows a length code. Each | ||
26 | length or distance code actually represents a base value and a number | ||
27 | of "extra" (sometimes zero) bits to get to add to the base value. At | ||
28 | the end of each deflated block is a special end-of-block (EOB) literal/ | ||
29 | length code. The decoding process is basically: get a literal/length | ||
30 | code; if EOB then done; if a literal, emit the decoded byte; if a | ||
31 | length then get the distance and emit the referred-to bytes from the | ||
32 | sliding window of previously emitted data. | ||
33 | |||
34 | There are (currently) three kinds of inflate blocks: stored, fixed, and | ||
35 | dynamic. The compressor deals with some chunk of data at a time, and | ||
36 | decides which method to use on a chunk-by-chunk basis. A chunk might | ||
37 | typically be 32 K or 64 K. If the chunk is incompressible, then the | ||
38 | "stored" method is used. In this case, the bytes are simply stored as | ||
39 | is, eight bits per byte, with none of the above coding. The bytes are | ||
40 | preceded by a count, since there is no longer an EOB code. | ||
41 | |||
42 | If the data is compressible, then either the fixed or dynamic methods | ||
43 | are used. In the dynamic method, the compressed data is preceded by | ||
44 | an encoding of the literal/length and distance Huffman codes that are | ||
45 | to be used to decode this block. The representation is itself Huffman | ||
46 | coded, and so is preceded by a description of that code. These code | ||
47 | descriptions take up a little space, and so for small blocks, there is | ||
48 | a predefined set of codes, called the fixed codes. The fixed method is | ||
49 | used if the block codes up smaller that way (usually for quite small | ||
50 | chunks), otherwise the dynamic method is used. In the latter case, the | ||
51 | codes are customized to the probabilities in the current block, and so | ||
52 | can code it much better than the pre-determined fixed codes. | ||
53 | |||
54 | The Huffman codes themselves are decoded using a multi-level table | ||
55 | lookup, in order to maximize the speed of decoding plus the speed of | ||
56 | building the decoding tables. See the comments below that precede the | ||
57 | lbits and dbits tuning parameters. | ||
58 | */ | ||
59 | |||
60 | |||
61 | /* | ||
62 | Notes beyond the 1.93a appnote.txt: | ||
63 | |||
64 | 1. Distance pointers never point before the beginning of the output | ||
65 | stream. | ||
66 | 2. Distance pointers can point back across blocks, up to 32k away. | ||
67 | 3. There is an implied maximum of 7 bits for the bit length table and | ||
68 | 15 bits for the actual data. | ||
69 | 4. If only one code exists, then it is encoded using one bit. (Zero | ||
70 | would be more efficient, but perhaps a little confusing.) If two | ||
71 | codes exist, they are coded using one bit each (0 and 1). | ||
72 | 5. There is no way of sending zero distance codes--a dummy must be | ||
73 | sent if there are none. (History: a pre 2.0 version of PKZIP would | ||
74 | store blocks with no distance codes, but this was discovered to be | ||
75 | too harsh a criterion.) Valid only for 1.93a. 2.04c does allow | ||
76 | zero distance codes, which is sent as one code of zero bits in | ||
77 | length. | ||
78 | 6. There are up to 286 literal/length codes. Code 256 represents the | ||
79 | end-of-block. Note however that the static length tree defines | ||
80 | 288 codes just to fill out the Huffman codes. Codes 286 and 287 | ||
81 | cannot be used though, since there is no length base or extra bits | ||
82 | defined for them. Similarly, there are up to 30 distance codes. | ||
83 | However, static trees define 32 codes (all 5 bits) to fill out the | ||
84 | Huffman codes, but the last two had better not show up in the data. | ||
85 | 7. Unzip can check dynamic Huffman blocks for complete code sets. | ||
86 | The exception is that a single code would not be complete (see #4). | ||
87 | 8. The five bits following the block type is really the number of | ||
88 | literal codes sent minus 257. | ||
89 | 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits | ||
90 | (1+6+6). Therefore, to output three times the length, you output | ||
91 | three codes (1+1+1), whereas to output four times the same length, | ||
92 | you only need two codes (1+3). Hmm. | ||
93 | 10. In the tree reconstruction algorithm, Code = Code + Increment | ||
94 | only if BitLength(i) is not zero. (Pretty obvious.) | ||
95 | 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19) | ||
96 | 12. Note: length code 284 can represent 227-258, but length code 285 | ||
97 | really is 258. The last length deserves its own, short code | ||
98 | since it gets used a lot in very redundant files. The length | ||
99 | 258 is special since 258 - 3 (the min match length) is 255. | ||
100 | 13. The literal/length and distance code bit lengths are read as a | ||
101 | single stream of lengths. It is possible (and advantageous) for | ||
102 | a repeat code (16, 17, or 18) to go across the boundary between | ||
103 | the two sets of lengths. | ||
104 | */ | ||
105 | #include <linux/compiler.h> | ||
106 | |||
107 | #ifdef RCSID | ||
108 | static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #"; | ||
109 | #endif | ||
110 | |||
111 | #ifndef STATIC | ||
112 | |||
113 | #if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H) | ||
114 | # include <sys/types.h> | ||
115 | # include <stdlib.h> | ||
116 | #endif | ||
117 | |||
118 | #include "gzip.h" | ||
119 | #define STATIC | ||
120 | #endif /* !STATIC */ | ||
121 | |||
122 | #ifndef INIT | ||
123 | #define INIT | ||
124 | #endif | ||
125 | |||
126 | #define slide window | ||
127 | |||
128 | /* Huffman code lookup table entry--this entry is four bytes for machines | ||
129 | that have 16-bit pointers (e.g. PC's in the small or medium model). | ||
130 | Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16 | ||
131 | means that v is a literal, 16 < e < 32 means that v is a pointer to | ||
132 | the next table, which codes e - 16 bits, and lastly e == 99 indicates | ||
133 | an unused code. If a code with e == 99 is looked up, this implies an | ||
134 | error in the data. */ | ||
135 | struct huft { | ||
136 | uch e; /* number of extra bits or operation */ | ||
137 | uch b; /* number of bits in this code or subcode */ | ||
138 | union { | ||
139 | ush n; /* literal, length base, or distance base */ | ||
140 | struct huft *t; /* pointer to next level of table */ | ||
141 | } v; | ||
142 | }; | ||
143 | |||
144 | |||
145 | /* Function prototypes */ | ||
146 | STATIC int INIT huft_build OF((unsigned *, unsigned, unsigned, | ||
147 | const ush *, const ush *, struct huft **, int *)); | ||
148 | STATIC int INIT huft_free OF((struct huft *)); | ||
149 | STATIC int INIT inflate_codes OF((struct huft *, struct huft *, int, int)); | ||
150 | STATIC int INIT inflate_stored OF((void)); | ||
151 | STATIC int INIT inflate_fixed OF((void)); | ||
152 | STATIC int INIT inflate_dynamic OF((void)); | ||
153 | STATIC int INIT inflate_block OF((int *)); | ||
154 | STATIC int INIT inflate OF((void)); | ||
155 | |||
156 | |||
157 | /* The inflate algorithm uses a sliding 32 K byte window on the uncompressed | ||
158 | stream to find repeated byte strings. This is implemented here as a | ||
159 | circular buffer. The index is updated simply by incrementing and then | ||
160 | ANDing with 0x7fff (32K-1). */ | ||
161 | /* It is left to other modules to supply the 32 K area. It is assumed | ||
162 | to be usable as if it were declared "uch slide[32768];" or as just | ||
163 | "uch *slide;" and then malloc'ed in the latter case. The definition | ||
164 | must be in unzip.h, included above. */ | ||
165 | /* unsigned wp; current position in slide */ | ||
166 | #define wp outcnt | ||
167 | #define flush_output(w) (wp=(w),flush_window()) | ||
168 | |||
169 | /* Tables for deflate from PKZIP's appnote.txt. */ | ||
170 | static const unsigned border[] = { /* Order of the bit length code lengths */ | ||
171 | 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; | ||
172 | static const ush cplens[] = { /* Copy lengths for literal codes 257..285 */ | ||
173 | 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, | ||
174 | 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; | ||
175 | /* note: see note #13 above about the 258 in this list. */ | ||
176 | static const ush cplext[] = { /* Extra bits for literal codes 257..285 */ | ||
177 | 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, | ||
178 | 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */ | ||
179 | static const ush cpdist[] = { /* Copy offsets for distance codes 0..29 */ | ||
180 | 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, | ||
181 | 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, | ||
182 | 8193, 12289, 16385, 24577}; | ||
183 | static const ush cpdext[] = { /* Extra bits for distance codes */ | ||
184 | 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, | ||
185 | 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, | ||
186 | 12, 12, 13, 13}; | ||
187 | |||
188 | |||
189 | |||
190 | /* Macros for inflate() bit peeking and grabbing. | ||
191 | The usage is: | ||
192 | |||
193 | NEEDBITS(j) | ||
194 | x = b & mask_bits[j]; | ||
195 | DUMPBITS(j) | ||
196 | |||
197 | where NEEDBITS makes sure that b has at least j bits in it, and | ||
198 | DUMPBITS removes the bits from b. The macros use the variable k | ||
199 | for the number of bits in b. Normally, b and k are register | ||
200 | variables for speed, and are initialized at the beginning of a | ||
201 | routine that uses these macros from a global bit buffer and count. | ||
202 | |||
203 | If we assume that EOB will be the longest code, then we will never | ||
204 | ask for bits with NEEDBITS that are beyond the end of the stream. | ||
205 | So, NEEDBITS should not read any more bytes than are needed to | ||
206 | meet the request. Then no bytes need to be "returned" to the buffer | ||
207 | at the end of the last block. | ||
208 | |||
209 | However, this assumption is not true for fixed blocks--the EOB code | ||
210 | is 7 bits, but the other literal/length codes can be 8 or 9 bits. | ||
211 | (The EOB code is shorter than other codes because fixed blocks are | ||
212 | generally short. So, while a block always has an EOB, many other | ||
213 | literal/length codes have a significantly lower probability of | ||
214 | showing up at all.) However, by making the first table have a | ||
215 | lookup of seven bits, the EOB code will be found in that first | ||
216 | lookup, and so will not require that too many bits be pulled from | ||
217 | the stream. | ||
218 | */ | ||
219 | |||
220 | STATIC ulg bb; /* bit buffer */ | ||
221 | STATIC unsigned bk; /* bits in bit buffer */ | ||
222 | |||
223 | STATIC const ush mask_bits[] = { | ||
224 | 0x0000, | ||
225 | 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, | ||
226 | 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff | ||
227 | }; | ||
228 | |||
229 | #define NEXTBYTE() ({ int v = get_byte(); if (v < 0) goto underrun; (uch)v; }) | ||
230 | #define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}} | ||
231 | #define DUMPBITS(n) {b>>=(n);k-=(n);} | ||
232 | |||
233 | |||
234 | /* | ||
235 | Huffman code decoding is performed using a multi-level table lookup. | ||
236 | The fastest way to decode is to simply build a lookup table whose | ||
237 | size is determined by the longest code. However, the time it takes | ||
238 | to build this table can also be a factor if the data being decoded | ||
239 | is not very long. The most common codes are necessarily the | ||
240 | shortest codes, so those codes dominate the decoding time, and hence | ||
241 | the speed. The idea is you can have a shorter table that decodes the | ||
242 | shorter, more probable codes, and then point to subsidiary tables for | ||
243 | the longer codes. The time it costs to decode the longer codes is | ||
244 | then traded against the time it takes to make longer tables. | ||
245 | |||
246 | This results of this trade are in the variables lbits and dbits | ||
247 | below. lbits is the number of bits the first level table for literal/ | ||
248 | length codes can decode in one step, and dbits is the same thing for | ||
249 | the distance codes. Subsequent tables are also less than or equal to | ||
250 | those sizes. These values may be adjusted either when all of the | ||
251 | codes are shorter than that, in which case the longest code length in | ||
252 | bits is used, or when the shortest code is *longer* than the requested | ||
253 | table size, in which case the length of the shortest code in bits is | ||
254 | used. | ||
255 | |||
256 | There are two different values for the two tables, since they code a | ||
257 | different number of possibilities each. The literal/length table | ||
258 | codes 286 possible values, or in a flat code, a little over eight | ||
259 | bits. The distance table codes 30 possible values, or a little less | ||
260 | than five bits, flat. The optimum values for speed end up being | ||
261 | about one bit more than those, so lbits is 8+1 and dbits is 5+1. | ||
262 | The optimum values may differ though from machine to machine, and | ||
263 | possibly even between compilers. Your mileage may vary. | ||
264 | */ | ||
265 | |||
266 | |||
267 | STATIC const int lbits = 9; /* bits in base literal/length lookup table */ | ||
268 | STATIC const int dbits = 6; /* bits in base distance lookup table */ | ||
269 | |||
270 | |||
271 | /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */ | ||
272 | #define BMAX 16 /* maximum bit length of any code (16 for explode) */ | ||
273 | #define N_MAX 288 /* maximum number of codes in any set */ | ||
274 | |||
275 | |||
276 | STATIC unsigned hufts; /* track memory usage */ | ||
277 | |||
278 | |||
279 | STATIC int INIT huft_build( | ||
280 | unsigned *b, /* code lengths in bits (all assumed <= BMAX) */ | ||
281 | unsigned n, /* number of codes (assumed <= N_MAX) */ | ||
282 | unsigned s, /* number of simple-valued codes (0..s-1) */ | ||
283 | const ush *d, /* list of base values for non-simple codes */ | ||
284 | const ush *e, /* list of extra bits for non-simple codes */ | ||
285 | struct huft **t, /* result: starting table */ | ||
286 | int *m /* maximum lookup bits, returns actual */ | ||
287 | ) | ||
288 | /* Given a list of code lengths and a maximum table size, make a set of | ||
289 | tables to decode that set of codes. Return zero on success, one if | ||
290 | the given code set is incomplete (the tables are still built in this | ||
291 | case), two if the input is invalid (all zero length codes or an | ||
292 | oversubscribed set of lengths), and three if not enough memory. */ | ||
293 | { | ||
294 | unsigned a; /* counter for codes of length k */ | ||
295 | unsigned c[BMAX+1]; /* bit length count table */ | ||
296 | unsigned f; /* i repeats in table every f entries */ | ||
297 | int g; /* maximum code length */ | ||
298 | int h; /* table level */ | ||
299 | register unsigned i; /* counter, current code */ | ||
300 | register unsigned j; /* counter */ | ||
301 | register int k; /* number of bits in current code */ | ||
302 | int l; /* bits per table (returned in m) */ | ||
303 | register unsigned *p; /* pointer into c[], b[], or v[] */ | ||
304 | register struct huft *q; /* points to current table */ | ||
305 | struct huft r; /* table entry for structure assignment */ | ||
306 | struct huft *u[BMAX]; /* table stack */ | ||
307 | unsigned v[N_MAX]; /* values in order of bit length */ | ||
308 | register int w; /* bits before this table == (l * h) */ | ||
309 | unsigned x[BMAX+1]; /* bit offsets, then code stack */ | ||
310 | unsigned *xp; /* pointer into x */ | ||
311 | int y; /* number of dummy codes added */ | ||
312 | unsigned z; /* number of entries in current table */ | ||
313 | |||
314 | DEBG("huft1 "); | ||
315 | |||
316 | /* Generate counts for each bit length */ | ||
317 | memzero(c, sizeof(c)); | ||
318 | p = b; i = n; | ||
319 | do { | ||
320 | Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"), | ||
321 | n-i, *p)); | ||
322 | c[*p]++; /* assume all entries <= BMAX */ | ||
323 | p++; /* Can't combine with above line (Solaris bug) */ | ||
324 | } while (--i); | ||
325 | if (c[0] == n) /* null input--all zero length codes */ | ||
326 | { | ||
327 | *t = (struct huft *)NULL; | ||
328 | *m = 0; | ||
329 | return 0; | ||
330 | } | ||
331 | |||
332 | DEBG("huft2 "); | ||
333 | |||
334 | /* Find minimum and maximum length, bound *m by those */ | ||
335 | l = *m; | ||
336 | for (j = 1; j <= BMAX; j++) | ||
337 | if (c[j]) | ||
338 | break; | ||
339 | k = j; /* minimum code length */ | ||
340 | if ((unsigned)l < j) | ||
341 | l = j; | ||
342 | for (i = BMAX; i; i--) | ||
343 | if (c[i]) | ||
344 | break; | ||
345 | g = i; /* maximum code length */ | ||
346 | if ((unsigned)l > i) | ||
347 | l = i; | ||
348 | *m = l; | ||
349 | |||
350 | DEBG("huft3 "); | ||
351 | |||
352 | /* Adjust last length count to fill out codes, if needed */ | ||
353 | for (y = 1 << j; j < i; j++, y <<= 1) | ||
354 | if ((y -= c[j]) < 0) | ||
355 | return 2; /* bad input: more codes than bits */ | ||
356 | if ((y -= c[i]) < 0) | ||
357 | return 2; | ||
358 | c[i] += y; | ||
359 | |||
360 | DEBG("huft4 "); | ||
361 | |||
362 | /* Generate starting offsets into the value table for each length */ | ||
363 | x[1] = j = 0; | ||
364 | p = c + 1; xp = x + 2; | ||
365 | while (--i) { /* note that i == g from above */ | ||
366 | *xp++ = (j += *p++); | ||
367 | } | ||
368 | |||
369 | DEBG("huft5 "); | ||
370 | |||
371 | /* Make a table of values in order of bit lengths */ | ||
372 | p = b; i = 0; | ||
373 | do { | ||
374 | if ((j = *p++) != 0) | ||
375 | v[x[j]++] = i; | ||
376 | } while (++i < n); | ||
377 | |||
378 | DEBG("h6 "); | ||
379 | |||
380 | /* Generate the Huffman codes and for each, make the table entries */ | ||
381 | x[0] = i = 0; /* first Huffman code is zero */ | ||
382 | p = v; /* grab values in bit order */ | ||
383 | h = -1; /* no tables yet--level -1 */ | ||
384 | w = -l; /* bits decoded == (l * h) */ | ||
385 | u[0] = (struct huft *)NULL; /* just to keep compilers happy */ | ||
386 | q = (struct huft *)NULL; /* ditto */ | ||
387 | z = 0; /* ditto */ | ||
388 | DEBG("h6a "); | ||
389 | |||
390 | /* go through the bit lengths (k already is bits in shortest code) */ | ||
391 | for (; k <= g; k++) | ||
392 | { | ||
393 | DEBG("h6b "); | ||
394 | a = c[k]; | ||
395 | while (a--) | ||
396 | { | ||
397 | DEBG("h6b1 "); | ||
398 | /* here i is the Huffman code of length k bits for value *p */ | ||
399 | /* make tables up to required level */ | ||
400 | while (k > w + l) | ||
401 | { | ||
402 | DEBG1("1 "); | ||
403 | h++; | ||
404 | w += l; /* previous table always l bits */ | ||
405 | |||
406 | /* compute minimum size table less than or equal to l bits */ | ||
407 | z = (z = g - w) > (unsigned)l ? l : z; /* upper limit on table size */ | ||
408 | if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */ | ||
409 | { /* too few codes for k-w bit table */ | ||
410 | DEBG1("2 "); | ||
411 | f -= a + 1; /* deduct codes from patterns left */ | ||
412 | xp = c + k; | ||
413 | while (++j < z) /* try smaller tables up to z bits */ | ||
414 | { | ||
415 | if ((f <<= 1) <= *++xp) | ||
416 | break; /* enough codes to use up j bits */ | ||
417 | f -= *xp; /* else deduct codes from patterns */ | ||
418 | } | ||
419 | } | ||
420 | DEBG1("3 "); | ||
421 | z = 1 << j; /* table entries for j-bit table */ | ||
422 | |||
423 | /* allocate and link in new table */ | ||
424 | if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) == | ||
425 | (struct huft *)NULL) | ||
426 | { | ||
427 | if (h) | ||
428 | huft_free(u[0]); | ||
429 | return 3; /* not enough memory */ | ||
430 | } | ||
431 | DEBG1("4 "); | ||
432 | hufts += z + 1; /* track memory usage */ | ||
433 | *t = q + 1; /* link to list for huft_free() */ | ||
434 | *(t = &(q->v.t)) = (struct huft *)NULL; | ||
435 | u[h] = ++q; /* table starts after link */ | ||
436 | |||
437 | DEBG1("5 "); | ||
438 | /* connect to last table, if there is one */ | ||
439 | if (h) | ||
440 | { | ||
441 | x[h] = i; /* save pattern for backing up */ | ||
442 | r.b = (uch)l; /* bits to dump before this table */ | ||
443 | r.e = (uch)(16 + j); /* bits in this table */ | ||
444 | r.v.t = q; /* pointer to this table */ | ||
445 | j = i >> (w - l); /* (get around Turbo C bug) */ | ||
446 | u[h-1][j] = r; /* connect to last table */ | ||
447 | } | ||
448 | DEBG1("6 "); | ||
449 | } | ||
450 | DEBG("h6c "); | ||
451 | |||
452 | /* set up table entry in r */ | ||
453 | r.b = (uch)(k - w); | ||
454 | if (p >= v + n) | ||
455 | r.e = 99; /* out of values--invalid code */ | ||
456 | else if (*p < s) | ||
457 | { | ||
458 | r.e = (uch)(*p < 256 ? 16 : 15); /* 256 is end-of-block code */ | ||
459 | r.v.n = (ush)(*p); /* simple code is just the value */ | ||
460 | p++; /* one compiler does not like *p++ */ | ||
461 | } | ||
462 | else | ||
463 | { | ||
464 | r.e = (uch)e[*p - s]; /* non-simple--look up in lists */ | ||
465 | r.v.n = d[*p++ - s]; | ||
466 | } | ||
467 | DEBG("h6d "); | ||
468 | |||
469 | /* fill code-like entries with r */ | ||
470 | f = 1 << (k - w); | ||
471 | for (j = i >> w; j < z; j += f) | ||
472 | q[j] = r; | ||
473 | |||
474 | /* backwards increment the k-bit code i */ | ||
475 | for (j = 1 << (k - 1); i & j; j >>= 1) | ||
476 | i ^= j; | ||
477 | i ^= j; | ||
478 | |||
479 | /* backup over finished tables */ | ||
480 | while ((i & ((1 << w) - 1)) != x[h]) | ||
481 | { | ||
482 | h--; /* don't need to update q */ | ||
483 | w -= l; | ||
484 | } | ||
485 | DEBG("h6e "); | ||
486 | } | ||
487 | DEBG("h6f "); | ||
488 | } | ||
489 | |||
490 | DEBG("huft7 "); | ||
491 | |||
492 | /* Return true (1) if we were given an incomplete table */ | ||
493 | return y != 0 && g != 1; | ||
494 | } | ||
495 | |||
496 | |||
497 | |||
498 | STATIC int INIT huft_free( | ||
499 | struct huft *t /* table to free */ | ||
500 | ) | ||
501 | /* Free the malloc'ed tables built by huft_build(), which makes a linked | ||
502 | list of the tables it made, with the links in a dummy first entry of | ||
503 | each table. */ | ||
504 | { | ||
505 | register struct huft *p, *q; | ||
506 | |||
507 | |||
508 | /* Go through linked list, freeing from the malloced (t[-1]) address. */ | ||
509 | p = t; | ||
510 | while (p != (struct huft *)NULL) | ||
511 | { | ||
512 | q = (--p)->v.t; | ||
513 | free((char*)p); | ||
514 | p = q; | ||
515 | } | ||
516 | return 0; | ||
517 | } | ||
518 | |||
519 | |||
520 | STATIC int INIT inflate_codes( | ||
521 | struct huft *tl, /* literal/length decoder tables */ | ||
522 | struct huft *td, /* distance decoder tables */ | ||
523 | int bl, /* number of bits decoded by tl[] */ | ||
524 | int bd /* number of bits decoded by td[] */ | ||
525 | ) | ||
526 | /* inflate (decompress) the codes in a deflated (compressed) block. | ||
527 | Return an error code or zero if it all goes ok. */ | ||
528 | { | ||
529 | register unsigned e; /* table entry flag/number of extra bits */ | ||
530 | unsigned n, d; /* length and index for copy */ | ||
531 | unsigned w; /* current window position */ | ||
532 | struct huft *t; /* pointer to table entry */ | ||
533 | unsigned ml, md; /* masks for bl and bd bits */ | ||
534 | register ulg b; /* bit buffer */ | ||
535 | register unsigned k; /* number of bits in bit buffer */ | ||
536 | |||
537 | |||
538 | /* make local copies of globals */ | ||
539 | b = bb; /* initialize bit buffer */ | ||
540 | k = bk; | ||
541 | w = wp; /* initialize window position */ | ||
542 | |||
543 | /* inflate the coded data */ | ||
544 | ml = mask_bits[bl]; /* precompute masks for speed */ | ||
545 | md = mask_bits[bd]; | ||
546 | for (;;) /* do until end of block */ | ||
547 | { | ||
548 | NEEDBITS((unsigned)bl) | ||
549 | if ((e = (t = tl + ((unsigned)b & ml))->e) > 16) | ||
550 | do { | ||
551 | if (e == 99) | ||
552 | return 1; | ||
553 | DUMPBITS(t->b) | ||
554 | e -= 16; | ||
555 | NEEDBITS(e) | ||
556 | } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16); | ||
557 | DUMPBITS(t->b) | ||
558 | if (e == 16) /* then it's a literal */ | ||
559 | { | ||
560 | slide[w++] = (uch)t->v.n; | ||
561 | Tracevv((stderr, "%c", slide[w-1])); | ||
562 | if (w == WSIZE) | ||
563 | { | ||
564 | flush_output(w); | ||
565 | w = 0; | ||
566 | } | ||
567 | } | ||
568 | else /* it's an EOB or a length */ | ||
569 | { | ||
570 | /* exit if end of block */ | ||
571 | if (e == 15) | ||
572 | break; | ||
573 | |||
574 | /* get length of block to copy */ | ||
575 | NEEDBITS(e) | ||
576 | n = t->v.n + ((unsigned)b & mask_bits[e]); | ||
577 | DUMPBITS(e); | ||
578 | |||
579 | /* decode distance of block to copy */ | ||
580 | NEEDBITS((unsigned)bd) | ||
581 | if ((e = (t = td + ((unsigned)b & md))->e) > 16) | ||
582 | do { | ||
583 | if (e == 99) | ||
584 | return 1; | ||
585 | DUMPBITS(t->b) | ||
586 | e -= 16; | ||
587 | NEEDBITS(e) | ||
588 | } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16); | ||
589 | DUMPBITS(t->b) | ||
590 | NEEDBITS(e) | ||
591 | d = w - t->v.n - ((unsigned)b & mask_bits[e]); | ||
592 | DUMPBITS(e) | ||
593 | Tracevv((stderr,"\\[%d,%d]", w-d, n)); | ||
594 | |||
595 | /* do the copy */ | ||
596 | do { | ||
597 | n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); | ||
598 | #if !defined(NOMEMCPY) && !defined(DEBUG) | ||
599 | if (w - d >= e) /* (this test assumes unsigned comparison) */ | ||
600 | { | ||
601 | memcpy(slide + w, slide + d, e); | ||
602 | w += e; | ||
603 | d += e; | ||
604 | } | ||
605 | else /* do it slow to avoid memcpy() overlap */ | ||
606 | #endif /* !NOMEMCPY */ | ||
607 | do { | ||
608 | slide[w++] = slide[d++]; | ||
609 | Tracevv((stderr, "%c", slide[w-1])); | ||
610 | } while (--e); | ||
611 | if (w == WSIZE) | ||
612 | { | ||
613 | flush_output(w); | ||
614 | w = 0; | ||
615 | } | ||
616 | } while (n); | ||
617 | } | ||
618 | } | ||
619 | |||
620 | |||
621 | /* restore the globals from the locals */ | ||
622 | wp = w; /* restore global window pointer */ | ||
623 | bb = b; /* restore global bit buffer */ | ||
624 | bk = k; | ||
625 | |||
626 | /* done */ | ||
627 | return 0; | ||
628 | |||
629 | underrun: | ||
630 | return 4; /* Input underrun */ | ||
631 | } | ||
632 | |||
633 | |||
634 | |||
635 | STATIC int INIT inflate_stored(void) | ||
636 | /* "decompress" an inflated type 0 (stored) block. */ | ||
637 | { | ||
638 | unsigned n; /* number of bytes in block */ | ||
639 | unsigned w; /* current window position */ | ||
640 | register ulg b; /* bit buffer */ | ||
641 | register unsigned k; /* number of bits in bit buffer */ | ||
642 | |||
643 | DEBG("<stor"); | ||
644 | |||
645 | /* make local copies of globals */ | ||
646 | b = bb; /* initialize bit buffer */ | ||
647 | k = bk; | ||
648 | w = wp; /* initialize window position */ | ||
649 | |||
650 | |||
651 | /* go to byte boundary */ | ||
652 | n = k & 7; | ||
653 | DUMPBITS(n); | ||
654 | |||
655 | |||
656 | /* get the length and its complement */ | ||
657 | NEEDBITS(16) | ||
658 | n = ((unsigned)b & 0xffff); | ||
659 | DUMPBITS(16) | ||
660 | NEEDBITS(16) | ||
661 | if (n != (unsigned)((~b) & 0xffff)) | ||
662 | return 1; /* error in compressed data */ | ||
663 | DUMPBITS(16) | ||
664 | |||
665 | |||
666 | /* read and output the compressed data */ | ||
667 | while (n--) | ||
668 | { | ||
669 | NEEDBITS(8) | ||
670 | slide[w++] = (uch)b; | ||
671 | if (w == WSIZE) | ||
672 | { | ||
673 | flush_output(w); | ||
674 | w = 0; | ||
675 | } | ||
676 | DUMPBITS(8) | ||
677 | } | ||
678 | |||
679 | |||
680 | /* restore the globals from the locals */ | ||
681 | wp = w; /* restore global window pointer */ | ||
682 | bb = b; /* restore global bit buffer */ | ||
683 | bk = k; | ||
684 | |||
685 | DEBG(">"); | ||
686 | return 0; | ||
687 | |||
688 | underrun: | ||
689 | return 4; /* Input underrun */ | ||
690 | } | ||
691 | |||
692 | |||
693 | /* | ||
694 | * We use `noinline' here to prevent gcc-3.5 from using too much stack space | ||
695 | */ | ||
696 | STATIC int noinline INIT inflate_fixed(void) | ||
697 | /* decompress an inflated type 1 (fixed Huffman codes) block. We should | ||
698 | either replace this with a custom decoder, or at least precompute the | ||
699 | Huffman tables. */ | ||
700 | { | ||
701 | int i; /* temporary variable */ | ||
702 | struct huft *tl; /* literal/length code table */ | ||
703 | struct huft *td; /* distance code table */ | ||
704 | int bl; /* lookup bits for tl */ | ||
705 | int bd; /* lookup bits for td */ | ||
706 | unsigned l[288]; /* length list for huft_build */ | ||
707 | |||
708 | DEBG("<fix"); | ||
709 | |||
710 | /* set up literal table */ | ||
711 | for (i = 0; i < 144; i++) | ||
712 | l[i] = 8; | ||
713 | for (; i < 256; i++) | ||
714 | l[i] = 9; | ||
715 | for (; i < 280; i++) | ||
716 | l[i] = 7; | ||
717 | for (; i < 288; i++) /* make a complete, but wrong code set */ | ||
718 | l[i] = 8; | ||
719 | bl = 7; | ||
720 | if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) | ||
721 | return i; | ||
722 | |||
723 | |||
724 | /* set up distance table */ | ||
725 | for (i = 0; i < 30; i++) /* make an incomplete code set */ | ||
726 | l[i] = 5; | ||
727 | bd = 5; | ||
728 | if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) | ||
729 | { | ||
730 | huft_free(tl); | ||
731 | |||
732 | DEBG(">"); | ||
733 | return i; | ||
734 | } | ||
735 | |||
736 | |||
737 | /* decompress until an end-of-block code */ | ||
738 | if (inflate_codes(tl, td, bl, bd)) | ||
739 | return 1; | ||
740 | |||
741 | |||
742 | /* free the decoding tables, return */ | ||
743 | huft_free(tl); | ||
744 | huft_free(td); | ||
745 | return 0; | ||
746 | } | ||
747 | |||
748 | |||
749 | /* | ||
750 | * We use `noinline' here to prevent gcc-3.5 from using too much stack space | ||
751 | */ | ||
752 | STATIC int noinline INIT inflate_dynamic(void) | ||
753 | /* decompress an inflated type 2 (dynamic Huffman codes) block. */ | ||
754 | { | ||
755 | int i; /* temporary variables */ | ||
756 | unsigned j; | ||
757 | unsigned l; /* last length */ | ||
758 | unsigned m; /* mask for bit lengths table */ | ||
759 | unsigned n; /* number of lengths to get */ | ||
760 | struct huft *tl; /* literal/length code table */ | ||
761 | struct huft *td; /* distance code table */ | ||
762 | int bl; /* lookup bits for tl */ | ||
763 | int bd; /* lookup bits for td */ | ||
764 | unsigned nb; /* number of bit length codes */ | ||
765 | unsigned nl; /* number of literal/length codes */ | ||
766 | unsigned nd; /* number of distance codes */ | ||
767 | #ifdef PKZIP_BUG_WORKAROUND | ||
768 | unsigned ll[288+32]; /* literal/length and distance code lengths */ | ||
769 | #else | ||
770 | unsigned ll[286+30]; /* literal/length and distance code lengths */ | ||
771 | #endif | ||
772 | register ulg b; /* bit buffer */ | ||
773 | register unsigned k; /* number of bits in bit buffer */ | ||
774 | |||
775 | DEBG("<dyn"); | ||
776 | |||
777 | /* make local bit buffer */ | ||
778 | b = bb; | ||
779 | k = bk; | ||
780 | |||
781 | |||
782 | /* read in table lengths */ | ||
783 | NEEDBITS(5) | ||
784 | nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length codes */ | ||
785 | DUMPBITS(5) | ||
786 | NEEDBITS(5) | ||
787 | nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */ | ||
788 | DUMPBITS(5) | ||
789 | NEEDBITS(4) | ||
790 | nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */ | ||
791 | DUMPBITS(4) | ||
792 | #ifdef PKZIP_BUG_WORKAROUND | ||
793 | if (nl > 288 || nd > 32) | ||
794 | #else | ||
795 | if (nl > 286 || nd > 30) | ||
796 | #endif | ||
797 | return 1; /* bad lengths */ | ||
798 | |||
799 | DEBG("dyn1 "); | ||
800 | |||
801 | /* read in bit-length-code lengths */ | ||
802 | for (j = 0; j < nb; j++) | ||
803 | { | ||
804 | NEEDBITS(3) | ||
805 | ll[border[j]] = (unsigned)b & 7; | ||
806 | DUMPBITS(3) | ||
807 | } | ||
808 | for (; j < 19; j++) | ||
809 | ll[border[j]] = 0; | ||
810 | |||
811 | DEBG("dyn2 "); | ||
812 | |||
813 | /* build decoding table for trees--single level, 7 bit lookup */ | ||
814 | bl = 7; | ||
815 | if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) | ||
816 | { | ||
817 | if (i == 1) | ||
818 | huft_free(tl); | ||
819 | return i; /* incomplete code set */ | ||
820 | } | ||
821 | |||
822 | DEBG("dyn3 "); | ||
823 | |||
824 | /* read in literal and distance code lengths */ | ||
825 | n = nl + nd; | ||
826 | m = mask_bits[bl]; | ||
827 | i = l = 0; | ||
828 | while ((unsigned)i < n) | ||
829 | { | ||
830 | NEEDBITS((unsigned)bl) | ||
831 | j = (td = tl + ((unsigned)b & m))->b; | ||
832 | DUMPBITS(j) | ||
833 | j = td->v.n; | ||
834 | if (j < 16) /* length of code in bits (0..15) */ | ||
835 | ll[i++] = l = j; /* save last length in l */ | ||
836 | else if (j == 16) /* repeat last length 3 to 6 times */ | ||
837 | { | ||
838 | NEEDBITS(2) | ||
839 | j = 3 + ((unsigned)b & 3); | ||
840 | DUMPBITS(2) | ||
841 | if ((unsigned)i + j > n) | ||
842 | return 1; | ||
843 | while (j--) | ||
844 | ll[i++] = l; | ||
845 | } | ||
846 | else if (j == 17) /* 3 to 10 zero length codes */ | ||
847 | { | ||
848 | NEEDBITS(3) | ||
849 | j = 3 + ((unsigned)b & 7); | ||
850 | DUMPBITS(3) | ||
851 | if ((unsigned)i + j > n) | ||
852 | return 1; | ||
853 | while (j--) | ||
854 | ll[i++] = 0; | ||
855 | l = 0; | ||
856 | } | ||
857 | else /* j == 18: 11 to 138 zero length codes */ | ||
858 | { | ||
859 | NEEDBITS(7) | ||
860 | j = 11 + ((unsigned)b & 0x7f); | ||
861 | DUMPBITS(7) | ||
862 | if ((unsigned)i + j > n) | ||
863 | return 1; | ||
864 | while (j--) | ||
865 | ll[i++] = 0; | ||
866 | l = 0; | ||
867 | } | ||
868 | } | ||
869 | |||
870 | DEBG("dyn4 "); | ||
871 | |||
872 | /* free decoding table for trees */ | ||
873 | huft_free(tl); | ||
874 | |||
875 | DEBG("dyn5 "); | ||
876 | |||
877 | /* restore the global bit buffer */ | ||
878 | bb = b; | ||
879 | bk = k; | ||
880 | |||
881 | DEBG("dyn5a "); | ||
882 | |||
883 | /* build the decoding tables for literal/length and distance codes */ | ||
884 | bl = lbits; | ||
885 | if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) | ||
886 | { | ||
887 | DEBG("dyn5b "); | ||
888 | if (i == 1) { | ||
889 | error("incomplete literal tree"); | ||
890 | huft_free(tl); | ||
891 | } | ||
892 | return i; /* incomplete code set */ | ||
893 | } | ||
894 | DEBG("dyn5c "); | ||
895 | bd = dbits; | ||
896 | if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) | ||
897 | { | ||
898 | DEBG("dyn5d "); | ||
899 | if (i == 1) { | ||
900 | error("incomplete distance tree"); | ||
901 | #ifdef PKZIP_BUG_WORKAROUND | ||
902 | i = 0; | ||
903 | } | ||
904 | #else | ||
905 | huft_free(td); | ||
906 | } | ||
907 | huft_free(tl); | ||
908 | return i; /* incomplete code set */ | ||
909 | #endif | ||
910 | } | ||
911 | |||
912 | DEBG("dyn6 "); | ||
913 | |||
914 | /* decompress until an end-of-block code */ | ||
915 | if (inflate_codes(tl, td, bl, bd)) | ||
916 | return 1; | ||
917 | |||
918 | DEBG("dyn7 "); | ||
919 | |||
920 | /* free the decoding tables, return */ | ||
921 | huft_free(tl); | ||
922 | huft_free(td); | ||
923 | |||
924 | DEBG(">"); | ||
925 | return 0; | ||
926 | |||
927 | underrun: | ||
928 | return 4; /* Input underrun */ | ||
929 | } | ||
930 | |||
931 | |||
932 | |||
933 | STATIC int INIT inflate_block( | ||
934 | int *e /* last block flag */ | ||
935 | ) | ||
936 | /* decompress an inflated block */ | ||
937 | { | ||
938 | unsigned t; /* block type */ | ||
939 | register ulg b; /* bit buffer */ | ||
940 | register unsigned k; /* number of bits in bit buffer */ | ||
941 | |||
942 | DEBG("<blk"); | ||
943 | |||
944 | /* make local bit buffer */ | ||
945 | b = bb; | ||
946 | k = bk; | ||
947 | |||
948 | |||
949 | /* read in last block bit */ | ||
950 | NEEDBITS(1) | ||
951 | *e = (int)b & 1; | ||
952 | DUMPBITS(1) | ||
953 | |||
954 | |||
955 | /* read in block type */ | ||
956 | NEEDBITS(2) | ||
957 | t = (unsigned)b & 3; | ||
958 | DUMPBITS(2) | ||
959 | |||
960 | |||
961 | /* restore the global bit buffer */ | ||
962 | bb = b; | ||
963 | bk = k; | ||
964 | |||
965 | /* inflate that block type */ | ||
966 | if (t == 2) | ||
967 | return inflate_dynamic(); | ||
968 | if (t == 0) | ||
969 | return inflate_stored(); | ||
970 | if (t == 1) | ||
971 | return inflate_fixed(); | ||
972 | |||
973 | DEBG(">"); | ||
974 | |||
975 | /* bad block type */ | ||
976 | return 2; | ||
977 | |||
978 | underrun: | ||
979 | return 4; /* Input underrun */ | ||
980 | } | ||
981 | |||
982 | |||
983 | |||
984 | STATIC int INIT inflate(void) | ||
985 | /* decompress an inflated entry */ | ||
986 | { | ||
987 | int e; /* last block flag */ | ||
988 | int r; /* result code */ | ||
989 | unsigned h; /* maximum struct huft's malloc'ed */ | ||
990 | void *ptr; | ||
991 | |||
992 | /* initialize window, bit buffer */ | ||
993 | wp = 0; | ||
994 | bk = 0; | ||
995 | bb = 0; | ||
996 | |||
997 | |||
998 | /* decompress until the last block */ | ||
999 | h = 0; | ||
1000 | do { | ||
1001 | hufts = 0; | ||
1002 | gzip_mark(&ptr); | ||
1003 | if ((r = inflate_block(&e)) != 0) { | ||
1004 | gzip_release(&ptr); | ||
1005 | return r; | ||
1006 | } | ||
1007 | gzip_release(&ptr); | ||
1008 | if (hufts > h) | ||
1009 | h = hufts; | ||
1010 | } while (!e); | ||
1011 | |||
1012 | /* Undo too much lookahead. The next read will be byte aligned so we | ||
1013 | * can discard unused bits in the last meaningful byte. | ||
1014 | */ | ||
1015 | while (bk >= 8) { | ||
1016 | bk -= 8; | ||
1017 | inptr--; | ||
1018 | } | ||
1019 | |||
1020 | /* flush out slide */ | ||
1021 | flush_output(wp); | ||
1022 | |||
1023 | |||
1024 | /* return success */ | ||
1025 | #ifdef DEBUG | ||
1026 | fprintf(stderr, "<%u> ", h); | ||
1027 | #endif /* DEBUG */ | ||
1028 | return 0; | ||
1029 | } | ||
1030 | |||
1031 | /********************************************************************** | ||
1032 | * | ||
1033 | * The following are support routines for inflate.c | ||
1034 | * | ||
1035 | **********************************************************************/ | ||
1036 | |||
1037 | static ulg crc_32_tab[256]; | ||
1038 | static ulg crc; /* initialized in makecrc() so it'll reside in bss */ | ||
1039 | #define CRC_VALUE (crc ^ 0xffffffffUL) | ||
1040 | |||
1041 | /* | ||
1042 | * Code to compute the CRC-32 table. Borrowed from | ||
1043 | * gzip-1.0.3/makecrc.c. | ||
1044 | */ | ||
1045 | |||
1046 | static void INIT | ||
1047 | makecrc(void) | ||
1048 | { | ||
1049 | /* Not copyrighted 1990 Mark Adler */ | ||
1050 | |||
1051 | unsigned long c; /* crc shift register */ | ||
1052 | unsigned long e; /* polynomial exclusive-or pattern */ | ||
1053 | int i; /* counter for all possible eight bit values */ | ||
1054 | int k; /* byte being shifted into crc apparatus */ | ||
1055 | |||
1056 | /* terms of polynomial defining this crc (except x^32): */ | ||
1057 | static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; | ||
1058 | |||
1059 | /* Make exclusive-or pattern from polynomial */ | ||
1060 | e = 0; | ||
1061 | for (i = 0; i < sizeof(p)/sizeof(int); i++) | ||
1062 | e |= 1L << (31 - p[i]); | ||
1063 | |||
1064 | crc_32_tab[0] = 0; | ||
1065 | |||
1066 | for (i = 1; i < 256; i++) | ||
1067 | { | ||
1068 | c = 0; | ||
1069 | for (k = i | 256; k != 1; k >>= 1) | ||
1070 | { | ||
1071 | c = c & 1 ? (c >> 1) ^ e : c >> 1; | ||
1072 | if (k & 1) | ||
1073 | c ^= e; | ||
1074 | } | ||
1075 | crc_32_tab[i] = c; | ||
1076 | } | ||
1077 | |||
1078 | /* this is initialized here so this code could reside in ROM */ | ||
1079 | crc = (ulg)0xffffffffUL; /* shift register contents */ | ||
1080 | } | ||
1081 | |||
1082 | /* gzip flag byte */ | ||
1083 | #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ | ||
1084 | #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ | ||
1085 | #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ | ||
1086 | #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ | ||
1087 | #define COMMENT 0x10 /* bit 4 set: file comment present */ | ||
1088 | #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ | ||
1089 | #define RESERVED 0xC0 /* bit 6,7: reserved */ | ||
1090 | |||
1091 | /* | ||
1092 | * Do the uncompression! | ||
1093 | */ | ||
1094 | static int INIT gunzip(void) | ||
1095 | { | ||
1096 | uch flags; | ||
1097 | unsigned char magic[2]; /* magic header */ | ||
1098 | char method; | ||
1099 | ulg orig_crc = 0; /* original crc */ | ||
1100 | ulg orig_len = 0; /* original uncompressed length */ | ||
1101 | int res; | ||
1102 | |||
1103 | magic[0] = NEXTBYTE(); | ||
1104 | magic[1] = NEXTBYTE(); | ||
1105 | method = NEXTBYTE(); | ||
1106 | |||
1107 | if (magic[0] != 037 || | ||
1108 | ((magic[1] != 0213) && (magic[1] != 0236))) { | ||
1109 | error("bad gzip magic numbers"); | ||
1110 | return -1; | ||
1111 | } | ||
1112 | |||
1113 | /* We only support method #8, DEFLATED */ | ||
1114 | if (method != 8) { | ||
1115 | error("internal error, invalid method"); | ||
1116 | return -1; | ||
1117 | } | ||
1118 | |||
1119 | flags = (uch)get_byte(); | ||
1120 | if ((flags & ENCRYPTED) != 0) { | ||
1121 | error("Input is encrypted"); | ||
1122 | return -1; | ||
1123 | } | ||
1124 | if ((flags & CONTINUATION) != 0) { | ||
1125 | error("Multi part input"); | ||
1126 | return -1; | ||
1127 | } | ||
1128 | if ((flags & RESERVED) != 0) { | ||
1129 | error("Input has invalid flags"); | ||
1130 | return -1; | ||
1131 | } | ||
1132 | NEXTBYTE(); /* Get timestamp */ | ||
1133 | NEXTBYTE(); | ||
1134 | NEXTBYTE(); | ||
1135 | NEXTBYTE(); | ||
1136 | |||
1137 | (void)NEXTBYTE(); /* Ignore extra flags for the moment */ | ||
1138 | (void)NEXTBYTE(); /* Ignore OS type for the moment */ | ||
1139 | |||
1140 | if ((flags & EXTRA_FIELD) != 0) { | ||
1141 | unsigned len = (unsigned)NEXTBYTE(); | ||
1142 | len |= ((unsigned)NEXTBYTE())<<8; | ||
1143 | while (len--) (void)NEXTBYTE(); | ||
1144 | } | ||
1145 | |||
1146 | /* Get original file name if it was truncated */ | ||
1147 | if ((flags & ORIG_NAME) != 0) { | ||
1148 | /* Discard the old name */ | ||
1149 | while (NEXTBYTE() != 0) /* null */ ; | ||
1150 | } | ||
1151 | |||
1152 | /* Discard file comment if any */ | ||
1153 | if ((flags & COMMENT) != 0) { | ||
1154 | while (NEXTBYTE() != 0) /* null */ ; | ||
1155 | } | ||
1156 | |||
1157 | /* Decompress */ | ||
1158 | if ((res = inflate())) { | ||
1159 | switch (res) { | ||
1160 | case 0: | ||
1161 | break; | ||
1162 | case 1: | ||
1163 | error("invalid compressed format (err=1)"); | ||
1164 | break; | ||
1165 | case 2: | ||
1166 | error("invalid compressed format (err=2)"); | ||
1167 | break; | ||
1168 | case 3: | ||
1169 | error("out of memory"); | ||
1170 | break; | ||
1171 | case 4: | ||
1172 | error("out of input data"); | ||
1173 | break; | ||
1174 | default: | ||
1175 | error("invalid compressed format (other)"); | ||
1176 | } | ||
1177 | return -1; | ||
1178 | } | ||
1179 | |||
1180 | /* Get the crc and original length */ | ||
1181 | /* crc32 (see algorithm.doc) | ||
1182 | * uncompressed input size modulo 2^32 | ||
1183 | */ | ||
1184 | orig_crc = (ulg) NEXTBYTE(); | ||
1185 | orig_crc |= (ulg) NEXTBYTE() << 8; | ||
1186 | orig_crc |= (ulg) NEXTBYTE() << 16; | ||
1187 | orig_crc |= (ulg) NEXTBYTE() << 24; | ||
1188 | |||
1189 | orig_len = (ulg) NEXTBYTE(); | ||
1190 | orig_len |= (ulg) NEXTBYTE() << 8; | ||
1191 | orig_len |= (ulg) NEXTBYTE() << 16; | ||
1192 | orig_len |= (ulg) NEXTBYTE() << 24; | ||
1193 | |||
1194 | /* Validate decompression */ | ||
1195 | if (orig_crc != CRC_VALUE) { | ||
1196 | error("crc error"); | ||
1197 | return -1; | ||
1198 | } | ||
1199 | if (orig_len != bytes_out) { | ||
1200 | error("length error"); | ||
1201 | return -1; | ||
1202 | } | ||
1203 | return 0; | ||
1204 | |||
1205 | underrun: /* NEXTBYTE() goto's here if needed */ | ||
1206 | error("out of input data"); | ||
1207 | return -1; | ||
1208 | } | ||
1209 | |||
1210 | |||