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/zlib_inflate/inftrees.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/zlib_inflate/inftrees.c')
-rw-r--r-- | lib/zlib_inflate/inftrees.c | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/lib/zlib_inflate/inftrees.c b/lib/zlib_inflate/inftrees.c new file mode 100644 index 000000000000..874950ec4858 --- /dev/null +++ b/lib/zlib_inflate/inftrees.c | |||
@@ -0,0 +1,412 @@ | |||
1 | /* inftrees.c -- generate Huffman trees for efficient decoding | ||
2 | * Copyright (C) 1995-1998 Mark Adler | ||
3 | * For conditions of distribution and use, see copyright notice in zlib.h | ||
4 | */ | ||
5 | |||
6 | #include <linux/zutil.h> | ||
7 | #include "inftrees.h" | ||
8 | #include "infutil.h" | ||
9 | |||
10 | static const char inflate_copyright[] __attribute_used__ = | ||
11 | " inflate 1.1.3 Copyright 1995-1998 Mark Adler "; | ||
12 | /* | ||
13 | If you use the zlib library in a product, an acknowledgment is welcome | ||
14 | in the documentation of your product. If for some reason you cannot | ||
15 | include such an acknowledgment, I would appreciate that you keep this | ||
16 | copyright string in the executable of your product. | ||
17 | */ | ||
18 | struct internal_state; | ||
19 | |||
20 | /* simplify the use of the inflate_huft type with some defines */ | ||
21 | #define exop word.what.Exop | ||
22 | #define bits word.what.Bits | ||
23 | |||
24 | |||
25 | static int huft_build ( | ||
26 | uInt *, /* code lengths in bits */ | ||
27 | uInt, /* number of codes */ | ||
28 | uInt, /* number of "simple" codes */ | ||
29 | const uInt *, /* list of base values for non-simple codes */ | ||
30 | const uInt *, /* list of extra bits for non-simple codes */ | ||
31 | inflate_huft **, /* result: starting table */ | ||
32 | uInt *, /* maximum lookup bits (returns actual) */ | ||
33 | inflate_huft *, /* space for trees */ | ||
34 | uInt *, /* hufts used in space */ | ||
35 | uInt * ); /* space for values */ | ||
36 | |||
37 | /* Tables for deflate from PKZIP's appnote.txt. */ | ||
38 | static const uInt cplens[31] = { /* Copy lengths for literal codes 257..285 */ | ||
39 | 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, | ||
40 | 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; | ||
41 | /* see note #13 above about 258 */ | ||
42 | static const uInt cplext[31] = { /* Extra bits for literal codes 257..285 */ | ||
43 | 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, | ||
44 | 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 112, 112}; /* 112==invalid */ | ||
45 | static const uInt cpdist[30] = { /* Copy offsets for distance codes 0..29 */ | ||
46 | 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, | ||
47 | 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, | ||
48 | 8193, 12289, 16385, 24577}; | ||
49 | static const uInt cpdext[30] = { /* Extra bits for distance codes */ | ||
50 | 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, | ||
51 | 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, | ||
52 | 12, 12, 13, 13}; | ||
53 | |||
54 | /* | ||
55 | Huffman code decoding is performed using a multi-level table lookup. | ||
56 | The fastest way to decode is to simply build a lookup table whose | ||
57 | size is determined by the longest code. However, the time it takes | ||
58 | to build this table can also be a factor if the data being decoded | ||
59 | is not very long. The most common codes are necessarily the | ||
60 | shortest codes, so those codes dominate the decoding time, and hence | ||
61 | the speed. The idea is you can have a shorter table that decodes the | ||
62 | shorter, more probable codes, and then point to subsidiary tables for | ||
63 | the longer codes. The time it costs to decode the longer codes is | ||
64 | then traded against the time it takes to make longer tables. | ||
65 | |||
66 | This results of this trade are in the variables lbits and dbits | ||
67 | below. lbits is the number of bits the first level table for literal/ | ||
68 | length codes can decode in one step, and dbits is the same thing for | ||
69 | the distance codes. Subsequent tables are also less than or equal to | ||
70 | those sizes. These values may be adjusted either when all of the | ||
71 | codes are shorter than that, in which case the longest code length in | ||
72 | bits is used, or when the shortest code is *longer* than the requested | ||
73 | table size, in which case the length of the shortest code in bits is | ||
74 | used. | ||
75 | |||
76 | There are two different values for the two tables, since they code a | ||
77 | different number of possibilities each. The literal/length table | ||
78 | codes 286 possible values, or in a flat code, a little over eight | ||
79 | bits. The distance table codes 30 possible values, or a little less | ||
80 | than five bits, flat. The optimum values for speed end up being | ||
81 | about one bit more than those, so lbits is 8+1 and dbits is 5+1. | ||
82 | The optimum values may differ though from machine to machine, and | ||
83 | possibly even between compilers. Your mileage may vary. | ||
84 | */ | ||
85 | |||
86 | |||
87 | /* If BMAX needs to be larger than 16, then h and x[] should be uLong. */ | ||
88 | #define BMAX 15 /* maximum bit length of any code */ | ||
89 | |||
90 | static int huft_build( | ||
91 | uInt *b, /* code lengths in bits (all assumed <= BMAX) */ | ||
92 | uInt n, /* number of codes (assumed <= 288) */ | ||
93 | uInt s, /* number of simple-valued codes (0..s-1) */ | ||
94 | const uInt *d, /* list of base values for non-simple codes */ | ||
95 | const uInt *e, /* list of extra bits for non-simple codes */ | ||
96 | inflate_huft **t, /* result: starting table */ | ||
97 | uInt *m, /* maximum lookup bits, returns actual */ | ||
98 | inflate_huft *hp, /* space for trees */ | ||
99 | uInt *hn, /* hufts used in space */ | ||
100 | uInt *v /* working area: values in order of bit length */ | ||
101 | ) | ||
102 | /* Given a list of code lengths and a maximum table size, make a set of | ||
103 | tables to decode that set of codes. Return Z_OK on success, Z_BUF_ERROR | ||
104 | if the given code set is incomplete (the tables are still built in this | ||
105 | case), Z_DATA_ERROR if the input is invalid (an over-subscribed set of | ||
106 | lengths), or Z_MEM_ERROR if not enough memory. */ | ||
107 | { | ||
108 | |||
109 | uInt a; /* counter for codes of length k */ | ||
110 | uInt c[BMAX+1]; /* bit length count table */ | ||
111 | uInt f; /* i repeats in table every f entries */ | ||
112 | int g; /* maximum code length */ | ||
113 | int h; /* table level */ | ||
114 | register uInt i; /* counter, current code */ | ||
115 | register uInt j; /* counter */ | ||
116 | register int k; /* number of bits in current code */ | ||
117 | int l; /* bits per table (returned in m) */ | ||
118 | uInt mask; /* (1 << w) - 1, to avoid cc -O bug on HP */ | ||
119 | register uInt *p; /* pointer into c[], b[], or v[] */ | ||
120 | inflate_huft *q; /* points to current table */ | ||
121 | struct inflate_huft_s r; /* table entry for structure assignment */ | ||
122 | inflate_huft *u[BMAX]; /* table stack */ | ||
123 | register int w; /* bits before this table == (l * h) */ | ||
124 | uInt x[BMAX+1]; /* bit offsets, then code stack */ | ||
125 | uInt *xp; /* pointer into x */ | ||
126 | int y; /* number of dummy codes added */ | ||
127 | uInt z; /* number of entries in current table */ | ||
128 | |||
129 | |||
130 | /* Generate counts for each bit length */ | ||
131 | p = c; | ||
132 | #define C0 *p++ = 0; | ||
133 | #define C2 C0 C0 C0 C0 | ||
134 | #define C4 C2 C2 C2 C2 | ||
135 | C4 /* clear c[]--assume BMAX+1 is 16 */ | ||
136 | p = b; i = n; | ||
137 | do { | ||
138 | c[*p++]++; /* assume all entries <= BMAX */ | ||
139 | } while (--i); | ||
140 | if (c[0] == n) /* null input--all zero length codes */ | ||
141 | { | ||
142 | *t = NULL; | ||
143 | *m = 0; | ||
144 | return Z_OK; | ||
145 | } | ||
146 | |||
147 | |||
148 | /* Find minimum and maximum length, bound *m by those */ | ||
149 | l = *m; | ||
150 | for (j = 1; j <= BMAX; j++) | ||
151 | if (c[j]) | ||
152 | break; | ||
153 | k = j; /* minimum code length */ | ||
154 | if ((uInt)l < j) | ||
155 | l = j; | ||
156 | for (i = BMAX; i; i--) | ||
157 | if (c[i]) | ||
158 | break; | ||
159 | g = i; /* maximum code length */ | ||
160 | if ((uInt)l > i) | ||
161 | l = i; | ||
162 | *m = l; | ||
163 | |||
164 | |||
165 | /* Adjust last length count to fill out codes, if needed */ | ||
166 | for (y = 1 << j; j < i; j++, y <<= 1) | ||
167 | if ((y -= c[j]) < 0) | ||
168 | return Z_DATA_ERROR; | ||
169 | if ((y -= c[i]) < 0) | ||
170 | return Z_DATA_ERROR; | ||
171 | c[i] += y; | ||
172 | |||
173 | |||
174 | /* Generate starting offsets into the value table for each length */ | ||
175 | x[1] = j = 0; | ||
176 | p = c + 1; xp = x + 2; | ||
177 | while (--i) { /* note that i == g from above */ | ||
178 | *xp++ = (j += *p++); | ||
179 | } | ||
180 | |||
181 | |||
182 | /* Make a table of values in order of bit lengths */ | ||
183 | p = b; i = 0; | ||
184 | do { | ||
185 | if ((j = *p++) != 0) | ||
186 | v[x[j]++] = i; | ||
187 | } while (++i < n); | ||
188 | n = x[g]; /* set n to length of v */ | ||
189 | |||
190 | |||
191 | /* Generate the Huffman codes and for each, make the table entries */ | ||
192 | x[0] = i = 0; /* first Huffman code is zero */ | ||
193 | p = v; /* grab values in bit order */ | ||
194 | h = -1; /* no tables yet--level -1 */ | ||
195 | w = -l; /* bits decoded == (l * h) */ | ||
196 | u[0] = NULL; /* just to keep compilers happy */ | ||
197 | q = NULL; /* ditto */ | ||
198 | z = 0; /* ditto */ | ||
199 | |||
200 | /* go through the bit lengths (k already is bits in shortest code) */ | ||
201 | for (; k <= g; k++) | ||
202 | { | ||
203 | a = c[k]; | ||
204 | while (a--) | ||
205 | { | ||
206 | /* here i is the Huffman code of length k bits for value *p */ | ||
207 | /* make tables up to required level */ | ||
208 | while (k > w + l) | ||
209 | { | ||
210 | h++; | ||
211 | w += l; /* previous table always l bits */ | ||
212 | |||
213 | /* compute minimum size table less than or equal to l bits */ | ||
214 | z = g - w; | ||
215 | z = z > (uInt)l ? l : z; /* table size upper limit */ | ||
216 | if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */ | ||
217 | { /* too few codes for k-w bit table */ | ||
218 | f -= a + 1; /* deduct codes from patterns left */ | ||
219 | xp = c + k; | ||
220 | if (j < z) | ||
221 | while (++j < z) /* try smaller tables up to z bits */ | ||
222 | { | ||
223 | if ((f <<= 1) <= *++xp) | ||
224 | break; /* enough codes to use up j bits */ | ||
225 | f -= *xp; /* else deduct codes from patterns */ | ||
226 | } | ||
227 | } | ||
228 | z = 1 << j; /* table entries for j-bit table */ | ||
229 | |||
230 | /* allocate new table */ | ||
231 | if (*hn + z > MANY) /* (note: doesn't matter for fixed) */ | ||
232 | return Z_DATA_ERROR; /* overflow of MANY */ | ||
233 | u[h] = q = hp + *hn; | ||
234 | *hn += z; | ||
235 | |||
236 | /* connect to last table, if there is one */ | ||
237 | if (h) | ||
238 | { | ||
239 | x[h] = i; /* save pattern for backing up */ | ||
240 | r.bits = (Byte)l; /* bits to dump before this table */ | ||
241 | r.exop = (Byte)j; /* bits in this table */ | ||
242 | j = i >> (w - l); | ||
243 | r.base = (uInt)(q - u[h-1] - j); /* offset to this table */ | ||
244 | u[h-1][j] = r; /* connect to last table */ | ||
245 | } | ||
246 | else | ||
247 | *t = q; /* first table is returned result */ | ||
248 | } | ||
249 | |||
250 | /* set up table entry in r */ | ||
251 | r.bits = (Byte)(k - w); | ||
252 | if (p >= v + n) | ||
253 | r.exop = 128 + 64; /* out of values--invalid code */ | ||
254 | else if (*p < s) | ||
255 | { | ||
256 | r.exop = (Byte)(*p < 256 ? 0 : 32 + 64); /* 256 is end-of-block */ | ||
257 | r.base = *p++; /* simple code is just the value */ | ||
258 | } | ||
259 | else | ||
260 | { | ||
261 | r.exop = (Byte)(e[*p - s] + 16 + 64);/* non-simple--look up in lists */ | ||
262 | r.base = d[*p++ - s]; | ||
263 | } | ||
264 | |||
265 | /* fill code-like entries with r */ | ||
266 | f = 1 << (k - w); | ||
267 | for (j = i >> w; j < z; j += f) | ||
268 | q[j] = r; | ||
269 | |||
270 | /* backwards increment the k-bit code i */ | ||
271 | for (j = 1 << (k - 1); i & j; j >>= 1) | ||
272 | i ^= j; | ||
273 | i ^= j; | ||
274 | |||
275 | /* backup over finished tables */ | ||
276 | mask = (1 << w) - 1; /* needed on HP, cc -O bug */ | ||
277 | while ((i & mask) != x[h]) | ||
278 | { | ||
279 | h--; /* don't need to update q */ | ||
280 | w -= l; | ||
281 | mask = (1 << w) - 1; | ||
282 | } | ||
283 | } | ||
284 | } | ||
285 | |||
286 | |||
287 | /* Return Z_BUF_ERROR if we were given an incomplete table */ | ||
288 | return y != 0 && g != 1 ? Z_BUF_ERROR : Z_OK; | ||
289 | } | ||
290 | |||
291 | |||
292 | int zlib_inflate_trees_bits( | ||
293 | uInt *c, /* 19 code lengths */ | ||
294 | uInt *bb, /* bits tree desired/actual depth */ | ||
295 | inflate_huft **tb, /* bits tree result */ | ||
296 | inflate_huft *hp, /* space for trees */ | ||
297 | z_streamp z /* for messages */ | ||
298 | ) | ||
299 | { | ||
300 | int r; | ||
301 | uInt hn = 0; /* hufts used in space */ | ||
302 | uInt *v; /* work area for huft_build */ | ||
303 | |||
304 | v = WS(z)->tree_work_area_1; | ||
305 | r = huft_build(c, 19, 19, NULL, NULL, tb, bb, hp, &hn, v); | ||
306 | if (r == Z_DATA_ERROR) | ||
307 | z->msg = (char*)"oversubscribed dynamic bit lengths tree"; | ||
308 | else if (r == Z_BUF_ERROR || *bb == 0) | ||
309 | { | ||
310 | z->msg = (char*)"incomplete dynamic bit lengths tree"; | ||
311 | r = Z_DATA_ERROR; | ||
312 | } | ||
313 | return r; | ||
314 | } | ||
315 | |||
316 | int zlib_inflate_trees_dynamic( | ||
317 | uInt nl, /* number of literal/length codes */ | ||
318 | uInt nd, /* number of distance codes */ | ||
319 | uInt *c, /* that many (total) code lengths */ | ||
320 | uInt *bl, /* literal desired/actual bit depth */ | ||
321 | uInt *bd, /* distance desired/actual bit depth */ | ||
322 | inflate_huft **tl, /* literal/length tree result */ | ||
323 | inflate_huft **td, /* distance tree result */ | ||
324 | inflate_huft *hp, /* space for trees */ | ||
325 | z_streamp z /* for messages */ | ||
326 | ) | ||
327 | { | ||
328 | int r; | ||
329 | uInt hn = 0; /* hufts used in space */ | ||
330 | uInt *v; /* work area for huft_build */ | ||
331 | |||
332 | /* allocate work area */ | ||
333 | v = WS(z)->tree_work_area_2; | ||
334 | |||
335 | /* build literal/length tree */ | ||
336 | r = huft_build(c, nl, 257, cplens, cplext, tl, bl, hp, &hn, v); | ||
337 | if (r != Z_OK || *bl == 0) | ||
338 | { | ||
339 | if (r == Z_DATA_ERROR) | ||
340 | z->msg = (char*)"oversubscribed literal/length tree"; | ||
341 | else if (r != Z_MEM_ERROR) | ||
342 | { | ||
343 | z->msg = (char*)"incomplete literal/length tree"; | ||
344 | r = Z_DATA_ERROR; | ||
345 | } | ||
346 | return r; | ||
347 | } | ||
348 | |||
349 | /* build distance tree */ | ||
350 | r = huft_build(c + nl, nd, 0, cpdist, cpdext, td, bd, hp, &hn, v); | ||
351 | if (r != Z_OK || (*bd == 0 && nl > 257)) | ||
352 | { | ||
353 | if (r == Z_DATA_ERROR) | ||
354 | z->msg = (char*)"oversubscribed distance tree"; | ||
355 | else if (r == Z_BUF_ERROR) { | ||
356 | #ifdef PKZIP_BUG_WORKAROUND | ||
357 | r = Z_OK; | ||
358 | } | ||
359 | #else | ||
360 | z->msg = (char*)"incomplete distance tree"; | ||
361 | r = Z_DATA_ERROR; | ||
362 | } | ||
363 | else if (r != Z_MEM_ERROR) | ||
364 | { | ||
365 | z->msg = (char*)"empty distance tree with lengths"; | ||
366 | r = Z_DATA_ERROR; | ||
367 | } | ||
368 | return r; | ||
369 | #endif | ||
370 | } | ||
371 | |||
372 | /* done */ | ||
373 | return Z_OK; | ||
374 | } | ||
375 | |||
376 | |||
377 | int zlib_inflate_trees_fixed( | ||
378 | uInt *bl, /* literal desired/actual bit depth */ | ||
379 | uInt *bd, /* distance desired/actual bit depth */ | ||
380 | inflate_huft **tl, /* literal/length tree result */ | ||
381 | inflate_huft **td, /* distance tree result */ | ||
382 | inflate_huft *hp, /* space for trees */ | ||
383 | z_streamp z /* for memory allocation */ | ||
384 | ) | ||
385 | { | ||
386 | int i; /* temporary variable */ | ||
387 | unsigned l[288]; /* length list for huft_build */ | ||
388 | uInt *v; /* work area for huft_build */ | ||
389 | |||
390 | /* set up literal table */ | ||
391 | for (i = 0; i < 144; i++) | ||
392 | l[i] = 8; | ||
393 | for (; i < 256; i++) | ||
394 | l[i] = 9; | ||
395 | for (; i < 280; i++) | ||
396 | l[i] = 7; | ||
397 | for (; i < 288; i++) /* make a complete, but wrong code set */ | ||
398 | l[i] = 8; | ||
399 | *bl = 9; | ||
400 | v = WS(z)->tree_work_area_1; | ||
401 | if ((i = huft_build(l, 288, 257, cplens, cplext, tl, bl, hp, &i, v)) != 0) | ||
402 | return i; | ||
403 | |||
404 | /* set up distance table */ | ||
405 | for (i = 0; i < 30; i++) /* make an incomplete code set */ | ||
406 | l[i] = 5; | ||
407 | *bd = 5; | ||
408 | if ((i = huft_build(l, 30, 0, cpdist, cpdext, td, bd, hp, &i, v)) > 1) | ||
409 | return i; | ||
410 | |||
411 | return Z_OK; | ||
412 | } | ||