1 /* inflate.c -- Not copyrighted 1992 by Mark Adler
2 version c10p1, 10 January 1993 */
4 /* You can do whatever you like with this source file, though I would
5 prefer that if you modify it and redistribute it that you include
6 comments to that effect with your name and the date. Thank you.
7 [The history has been moved to the file ChangeLog.]
11 Inflate deflated (PKZIP's method 8 compressed) data. The compression
12 method searches for as much of the current string of bytes (up to a
13 length of 258) in the previous 32K bytes. If it doesn't find any
14 matches (of at least length 3), it codes the next byte. Otherwise, it
15 codes the length of the matched string and its distance backwards from
16 the current position. There is a single Huffman code that codes both
17 single bytes (called "literals") and match lengths. A second Huffman
18 code codes the distance information, which follows a length code. Each
19 length or distance code actually represents a base value and a number
20 of "extra" (sometimes zero) bits to get to add to the base value. At
21 the end of each deflated block is a special end-of-block (EOB) literal/
22 length code. The decoding process is basically: get a literal/length
23 code; if EOB then done; if a literal, emit the decoded byte; if a
24 length then get the distance and emit the referred-to bytes from the
25 sliding window of previously emitted data.
27 There are (currently) three kinds of inflate blocks: stored, fixed, and
28 dynamic. The compressor deals with some chunk of data at a time, and
29 decides which method to use on a chunk-by-chunk basis. A chunk might
30 typically be 32K or 64K. If the chunk is uncompressible, then the
31 "stored" method is used. In this case, the bytes are simply stored as
32 is, eight bits per byte, with none of the above coding. The bytes are
33 preceded by a count, since there is no longer an EOB code.
35 If the data is compressible, then either the fixed or dynamic methods
36 are used. In the dynamic method, the compressed data is preceded by
37 an encoding of the literal/length and distance Huffman codes that are
38 to be used to decode this block. The representation is itself Huffman
39 coded, and so is preceded by a description of that code. These code
40 descriptions take up a little space, and so for small blocks, there is
41 a predefined set of codes, called the fixed codes. The fixed method is
42 used if the block codes up smaller that way (usually for quite small
43 chunks), otherwise the dynamic method is used. In the latter case, the
44 codes are customized to the probabilities in the current block, and so
45 can code it much better than the pre-determined fixed codes.
47 The Huffman codes themselves are decoded using a mutli-level table
48 lookup, in order to maximize the speed of decoding plus the speed of
49 building the decoding tables. See the comments below that precede the
50 lbits and dbits tuning parameters.
55 Notes beyond the 1.93a appnote.txt:
57 1. Distance pointers never point before the beginning of the output
59 2. Distance pointers can point back across blocks, up to 32k away.
60 3. There is an implied maximum of 7 bits for the bit length table and
61 15 bits for the actual data.
62 4. If only one code exists, then it is encoded using one bit. (Zero
63 would be more efficient, but perhaps a little confusing.) If two
64 codes exist, they are coded using one bit each (0 and 1).
65 5. There is no way of sending zero distance codes--a dummy must be
66 sent if there are none. (History: a pre 2.0 version of PKZIP would
67 store blocks with no distance codes, but this was discovered to be
68 too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
69 zero distance codes, which is sent as one code of zero bits in
71 6. There are up to 286 literal/length codes. Code 256 represents the
72 end-of-block. Note however that the static length tree defines
73 288 codes just to fill out the Huffman codes. Codes 286 and 287
74 cannot be used though, since there is no length base or extra bits
75 defined for them. Similarly, there are up to 30 distance codes.
76 However, static trees define 32 codes (all 5 bits) to fill out the
77 Huffman codes, but the last two had better not show up in the data.
78 7. Unzip can check dynamic Huffman blocks for complete code sets.
79 The exception is that a single code would not be complete (see #4).
80 8. The five bits following the block type is really the number of
81 literal codes sent minus 257.
82 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
83 (1+6+6). Therefore, to output three times the length, you output
84 three codes (1+1+1), whereas to output four times the same length,
85 you only need two codes (1+3). Hmm.
86 10. In the tree reconstruction algorithm, Code = Code + Increment
87 only if BitLength(i) is not zero. (Pretty obvious.)
88 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
89 12. Note: length code 284 can represent 227-258, but length code 285
90 really is 258. The last length deserves its own, short code
91 since it gets used a lot in very redundant files. The length
92 258 is special since 258 - 3 (the min match length) is 255.
93 13. The literal/length and distance code bit lengths are read as a
94 single stream of lengths. It is possible (and advantageous) for
95 a repeat code (16, 17, or 18) to go across the boundary between
96 the two sets of lengths.
100 static char rcsid[] = "$Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp $";
106 #if defined STDC_HEADERS || defined HAVE_STDLIB_H
113 /* Huffman code lookup table entry--this entry is four bytes for machines
114 that have 16-bit pointers (e.g. PC's in the small or medium model).
115 Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
116 means that v is a literal, 16 < e < 32 means that v is a pointer to
117 the next table, which codes e - 16 bits, and lastly e == 99 indicates
118 an unused code. If a code with e == 99 is looked up, this implies an
119 error in the data. */
121 uch e; /* number of extra bits or operation */
122 uch b; /* number of bits in this code or subcode */
124 ush n; /* literal, length base, or distance base */
125 struct huft *t; /* pointer to next level of table */
130 /* Function prototypes */
131 int huft_build OF((unsigned *, unsigned, unsigned, ush *, ush *,
132 struct huft **, int *));
133 int huft_free OF((struct huft *));
134 int inflate_codes OF((struct huft *, struct huft *, int, int));
135 int inflate_stored OF((void));
136 int inflate_fixed OF((void));
137 int inflate_dynamic OF((void));
138 int inflate_block OF((int *));
139 int inflate OF((void));
142 /* The inflate algorithm uses a sliding 32K byte window on the uncompressed
143 stream to find repeated byte strings. This is implemented here as a
144 circular buffer. The index is updated simply by incrementing and then
145 and'ing with 0x7fff (32K-1). */
146 /* It is left to other modules to supply the 32K area. It is assumed
147 to be usable as if it were declared "uch slide[32768];" or as just
148 "uch *slide;" and then malloc'ed in the latter case. The definition
149 must be in unzip.h, included above. */
150 /* unsigned wp; current position in slide */
152 #define flush_output(w) (wp=(w),flush_window())
154 /* Tables for deflate from PKZIP's appnote.txt. */
155 static unsigned border[] = { /* Order of the bit length code lengths */
156 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
157 static ush cplens[] = { /* Copy lengths for literal codes 257..285 */
158 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
159 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
160 /* note: see note #13 above about the 258 in this list. */
161 static ush cplext[] = { /* Extra bits for literal codes 257..285 */
162 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
163 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */
164 static ush cpdist[] = { /* Copy offsets for distance codes 0..29 */
165 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
166 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
167 8193, 12289, 16385, 24577};
168 static ush cpdext[] = { /* Extra bits for distance codes */
169 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
170 7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
175 /* Macros for inflate() bit peeking and grabbing.
179 x = b & mask_bits[j];
182 where NEEDBITS makes sure that b has at least j bits in it, and
183 DUMPBITS removes the bits from b. The macros use the variable k
184 for the number of bits in b. Normally, b and k are register
185 variables for speed, and are initialized at the beginning of a
186 routine that uses these macros from a global bit buffer and count.
188 If we assume that EOB will be the longest code, then we will never
189 ask for bits with NEEDBITS that are beyond the end of the stream.
190 So, NEEDBITS should not read any more bytes than are needed to
191 meet the request. Then no bytes need to be "returned" to the buffer
192 at the end of the last block.
194 However, this assumption is not true for fixed blocks--the EOB code
195 is 7 bits, but the other literal/length codes can be 8 or 9 bits.
196 (The EOB code is shorter than other codes because fixed blocks are
197 generally short. So, while a block always has an EOB, many other
198 literal/length codes have a significantly lower probability of
199 showing up at all.) However, by making the first table have a
200 lookup of seven bits, the EOB code will be found in that first
201 lookup, and so will not require that too many bits be pulled from
205 ulg bb; /* bit buffer */
206 unsigned bk; /* bits in bit buffer */
210 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
211 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
216 # define NEXTBYTE() \
217 (decrypt ? (cc = get_byte(), zdecode(cc), cc) : get_byte())
219 # define NEXTBYTE() (uch)get_byte()
221 #define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}}
222 #define DUMPBITS(n) {b>>=(n);k-=(n);}
226 Huffman code decoding is performed using a multi-level table lookup.
227 The fastest way to decode is to simply build a lookup table whose
228 size is determined by the longest code. However, the time it takes
229 to build this table can also be a factor if the data being decoded
230 is not very long. The most common codes are necessarily the
231 shortest codes, so those codes dominate the decoding time, and hence
232 the speed. The idea is you can have a shorter table that decodes the
233 shorter, more probable codes, and then point to subsidiary tables for
234 the longer codes. The time it costs to decode the longer codes is
235 then traded against the time it takes to make longer tables.
237 This results of this trade are in the variables lbits and dbits
238 below. lbits is the number of bits the first level table for literal/
239 length codes can decode in one step, and dbits is the same thing for
240 the distance codes. Subsequent tables are also less than or equal to
241 those sizes. These values may be adjusted either when all of the
242 codes are shorter than that, in which case the longest code length in
243 bits is used, or when the shortest code is *longer* than the requested
244 table size, in which case the length of the shortest code in bits is
247 There are two different values for the two tables, since they code a
248 different number of possibilities each. The literal/length table
249 codes 286 possible values, or in a flat code, a little over eight
250 bits. The distance table codes 30 possible values, or a little less
251 than five bits, flat. The optimum values for speed end up being
252 about one bit more than those, so lbits is 8+1 and dbits is 5+1.
253 The optimum values may differ though from machine to machine, and
254 possibly even between compilers. Your mileage may vary.
258 int lbits = 9; /* bits in base literal/length lookup table */
259 int dbits = 6; /* bits in base distance lookup table */
262 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
263 #define BMAX 16 /* maximum bit length of any code (16 for explode) */
264 #define N_MAX 288 /* maximum number of codes in any set */
267 unsigned hufts; /* track memory usage */
270 int huft_build(b, n, s, d, e, t, m)
271 unsigned *b; /* code lengths in bits (all assumed <= BMAX) */
272 unsigned n; /* number of codes (assumed <= N_MAX) */
273 unsigned s; /* number of simple-valued codes (0..s-1) */
274 ush *d; /* list of base values for non-simple codes */
275 ush *e; /* list of extra bits for non-simple codes */
276 struct huft **t; /* result: starting table */
277 int *m; /* maximum lookup bits, returns actual */
278 /* Given a list of code lengths and a maximum table size, make a set of
279 tables to decode that set of codes. Return zero on success, one if
280 the given code set is incomplete (the tables are still built in this
281 case), two if the input is invalid (all zero length codes or an
282 oversubscribed set of lengths), and three if not enough memory. */
284 unsigned a; /* counter for codes of length k */
285 unsigned c[BMAX+1]; /* bit length count table */
286 unsigned f; /* i repeats in table every f entries */
287 int g; /* maximum code length */
288 int h; /* table level */
289 register unsigned i; /* counter, current code */
290 register unsigned j; /* counter */
291 register int k; /* number of bits in current code */
292 int l; /* bits per table (returned in m) */
293 register unsigned *p; /* pointer into c[], b[], or v[] */
294 register struct huft *q; /* points to current table */
295 struct huft r; /* table entry for structure assignment */
296 struct huft *u[BMAX]; /* table stack */
297 unsigned v[N_MAX]; /* values in order of bit length */
298 register int w; /* bits before this table == (l * h) */
299 unsigned x[BMAX+1]; /* bit offsets, then code stack */
300 unsigned *xp; /* pointer into x */
301 int y; /* number of dummy codes added */
302 unsigned z; /* number of entries in current table */
305 /* Generate counts for each bit length */
306 memzero(c, sizeof(c));
309 Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"),
311 c[*p]++; /* assume all entries <= BMAX */
312 p++; /* Can't combine with above line (Solaris bug) */
314 if (c[0] == n) /* null input--all zero length codes */
316 *t = (struct huft *)NULL;
322 /* Find minimum and maximum length, bound *m by those */
324 for (j = 1; j <= BMAX; j++)
327 k = j; /* minimum code length */
330 for (i = BMAX; i; i--)
333 g = i; /* maximum code length */
339 /* Adjust last length count to fill out codes, if needed */
340 for (y = 1 << j; j < i; j++, y <<= 1)
342 return 2; /* bad input: more codes than bits */
348 /* Generate starting offsets into the value table for each length */
350 p = c + 1; xp = x + 2;
351 while (--i) { /* note that i == g from above */
356 /* Make a table of values in order of bit lengths */
362 n = x[g]; /* set n to length of v */
365 /* Generate the Huffman codes and for each, make the table entries */
366 x[0] = i = 0; /* first Huffman code is zero */
367 p = v; /* grab values in bit order */
368 h = -1; /* no tables yet--level -1 */
369 w = -l; /* bits decoded == (l * h) */
370 u[0] = (struct huft *)NULL; /* just to keep compilers happy */
371 q = (struct huft *)NULL; /* ditto */
374 /* go through the bit lengths (k already is bits in shortest code) */
380 /* here i is the Huffman code of length k bits for value *p */
381 /* make tables up to required level */
385 w += l; /* previous table always l bits */
387 /* compute minimum size table less than or equal to l bits */
388 z = (z = g - w) > (unsigned)l ? l : z; /* upper limit on table size */
389 if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */
390 { /* too few codes for k-w bit table */
391 f -= a + 1; /* deduct codes from patterns left */
394 while (++j < z) /* try smaller tables up to z bits */
396 if ((f <<= 1) <= *++xp)
397 break; /* enough codes to use up j bits */
398 f -= *xp; /* else deduct codes from patterns */
401 z = 1 << j; /* table entries for j-bit table */
403 /* allocate and link in new table */
404 if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) ==
409 return 3; /* not enough memory */
411 hufts += z + 1; /* track memory usage */
412 *t = q + 1; /* link to list for huft_free() */
413 *(t = &(q->v.t)) = (struct huft *)NULL;
414 u[h] = ++q; /* table starts after link */
416 /* connect to last table, if there is one */
419 x[h] = i; /* save pattern for backing up */
420 r.b = (uch)l; /* bits to dump before this table */
421 r.e = (uch)(16 + j); /* bits in this table */
422 r.v.t = q; /* pointer to this table */
423 j = i >> (w - l); /* (get around Turbo C bug) */
424 u[h-1][j] = r; /* connect to last table */
428 /* set up table entry in r */
431 r.e = 99; /* out of values--invalid code */
434 r.e = (uch)(*p < 256 ? 16 : 15); /* 256 is end-of-block code */
435 r.v.n = (ush)(*p); /* simple code is just the value */
436 p++; /* one compiler does not like *p++ */
440 r.e = (uch)e[*p - s]; /* non-simple--look up in lists */
444 /* fill code-like entries with r */
446 for (j = i >> w; j < z; j += f)
449 /* backwards increment the k-bit code i */
450 for (j = 1 << (k - 1); i & j; j >>= 1)
454 /* backup over finished tables */
455 while ((i & ((1 << w) - 1)) != x[h])
457 h--; /* don't need to update q */
464 /* Return true (1) if we were given an incomplete table */
465 return y != 0 && g != 1;
471 struct huft *t; /* table to free */
472 /* Free the malloc'ed tables built by huft_build(), which makes a linked
473 list of the tables it made, with the links in a dummy first entry of
476 register struct huft *p, *q;
479 /* Go through linked list, freeing from the malloced (t[-1]) address. */
481 while (p != (struct huft *)NULL)
491 int inflate_codes(tl, td, bl, bd)
492 struct huft *tl, *td; /* literal/length and distance decoder tables */
493 int bl, bd; /* number of bits decoded by tl[] and td[] */
494 /* inflate (decompress) the codes in a deflated (compressed) block.
495 Return an error code or zero if it all goes ok. */
497 register unsigned e; /* table entry flag/number of extra bits */
498 unsigned n, d; /* length and index for copy */
499 unsigned w; /* current window position */
500 struct huft *t; /* pointer to table entry */
501 unsigned ml, md; /* masks for bl and bd bits */
502 register ulg b; /* bit buffer */
503 register unsigned k; /* number of bits in bit buffer */
506 /* make local copies of globals */
507 b = bb; /* initialize bit buffer */
509 w = wp; /* initialize window position */
511 /* inflate the coded data */
512 ml = mask_bits[bl]; /* precompute masks for speed */
514 for (;;) /* do until end of block */
516 NEEDBITS((unsigned)bl)
517 if ((e = (t = tl + ((unsigned)b & ml))->e) > 16)
524 } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16);
526 if (e == 16) /* then it's a literal */
528 slide[w++] = (uch)t->v.n;
529 Tracevv((stderr, "%c", slide[w-1]));
536 else /* it's an EOB or a length */
538 /* exit if end of block */
542 /* get length of block to copy */
544 n = t->v.n + ((unsigned)b & mask_bits[e]);
547 /* decode distance of block to copy */
548 NEEDBITS((unsigned)bd)
549 if ((e = (t = td + ((unsigned)b & md))->e) > 16)
556 } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16);
559 d = w - t->v.n - ((unsigned)b & mask_bits[e]);
561 Tracevv((stderr,"\\[%d,%d]", w-d, n));
565 n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e);
566 #if !defined(NOMEMCPY) && !defined(DEBUG)
567 if (w - d >= e) /* (this test assumes unsigned comparison) */
569 memcpy(slide + w, slide + d, e);
573 else /* do it slow to avoid memcpy() overlap */
574 #endif /* !NOMEMCPY */
576 slide[w++] = slide[d++];
577 Tracevv((stderr, "%c", slide[w-1]));
589 /* restore the globals from the locals */
590 wp = w; /* restore global window pointer */
591 bb = b; /* restore global bit buffer */
601 /* "decompress" an inflated type 0 (stored) block. */
603 unsigned n; /* number of bytes in block */
604 unsigned w; /* current window position */
605 register ulg b; /* bit buffer */
606 register unsigned k; /* number of bits in bit buffer */
609 /* make local copies of globals */
610 b = bb; /* initialize bit buffer */
612 w = wp; /* initialize window position */
615 /* go to byte boundary */
620 /* get the length and its complement */
622 n = ((unsigned)b & 0xffff);
625 if (n != (unsigned)((~b) & 0xffff))
626 return 1; /* error in compressed data */
630 /* read and output the compressed data */
644 /* restore the globals from the locals */
645 wp = w; /* restore global window pointer */
646 bb = b; /* restore global bit buffer */
654 /* decompress an inflated type 1 (fixed Huffman codes) block. We should
655 either replace this with a custom decoder, or at least precompute the
658 int i; /* temporary variable */
659 struct huft *tl; /* literal/length code table */
660 struct huft *td; /* distance code table */
661 int bl; /* lookup bits for tl */
662 int bd; /* lookup bits for td */
663 unsigned l[288]; /* length list for huft_build */
666 /* set up literal table */
667 for (i = 0; i < 144; i++)
673 for (; i < 288; i++) /* make a complete, but wrong code set */
676 if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0)
680 /* set up distance table */
681 for (i = 0; i < 30; i++) /* make an incomplete code set */
684 if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1)
691 /* decompress until an end-of-block code */
692 if (inflate_codes(tl, td, bl, bd))
696 /* free the decoding tables, return */
704 int inflate_dynamic()
705 /* decompress an inflated type 2 (dynamic Huffman codes) block. */
707 int i; /* temporary variables */
709 unsigned l; /* last length */
710 unsigned m; /* mask for bit lengths table */
711 unsigned n; /* number of lengths to get */
712 struct huft *tl; /* literal/length code table */
713 struct huft *td; /* distance code table */
714 int bl; /* lookup bits for tl */
715 int bd; /* lookup bits for td */
716 unsigned nb; /* number of bit length codes */
717 unsigned nl; /* number of literal/length codes */
718 unsigned nd; /* number of distance codes */
719 #ifdef PKZIP_BUG_WORKAROUND
720 unsigned ll[288+32]; /* literal/length and distance code lengths */
722 unsigned ll[286+30]; /* literal/length and distance code lengths */
724 register ulg b; /* bit buffer */
725 register unsigned k; /* number of bits in bit buffer */
728 /* make local bit buffer */
733 /* read in table lengths */
735 nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length codes */
738 nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */
741 nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */
743 #ifdef PKZIP_BUG_WORKAROUND
744 if (nl > 288 || nd > 32)
746 if (nl > 286 || nd > 30)
748 return 1; /* bad lengths */
751 /* read in bit-length-code lengths */
752 for (j = 0; j < nb; j++)
755 ll[border[j]] = (unsigned)b & 7;
762 /* build decoding table for trees--single level, 7 bit lookup */
764 if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0)
768 return i; /* incomplete code set */
771 if (tl == NULL) /* Grrrhhh */
774 /* read in literal and distance code lengths */
778 while ((unsigned)i < n)
780 NEEDBITS((unsigned)bl)
781 j = (td = tl + ((unsigned)b & m))->b;
784 if (j < 16) /* length of code in bits (0..15) */
785 ll[i++] = l = j; /* save last length in l */
786 else if (j == 16) /* repeat last length 3 to 6 times */
789 j = 3 + ((unsigned)b & 3);
791 if ((unsigned)i + j > n)
796 else if (j == 17) /* 3 to 10 zero length codes */
799 j = 3 + ((unsigned)b & 7);
801 if ((unsigned)i + j > n)
807 else /* j == 18: 11 to 138 zero length codes */
810 j = 11 + ((unsigned)b & 0x7f);
812 if ((unsigned)i + j > n)
821 /* free decoding table for trees */
825 /* restore the global bit buffer */
830 /* build the decoding tables for literal/length and distance codes */
832 if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0)
835 fprintf(stderr, " incomplete literal tree\n");
838 return i; /* incomplete code set */
841 if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0)
844 fprintf(stderr, " incomplete distance tree\n");
845 #ifdef PKZIP_BUG_WORKAROUND
852 return i; /* incomplete code set */
857 /* decompress until an end-of-block code */
858 if (inflate_codes(tl, td, bl, bd))
862 /* free the decoding tables, return */
871 int *e; /* last block flag */
872 /* decompress an inflated block */
874 unsigned t; /* block type */
875 register ulg b; /* bit buffer */
876 register unsigned k; /* number of bits in bit buffer */
879 /* make local bit buffer */
884 /* read in last block bit */
890 /* read in block type */
896 /* restore the global bit buffer */
901 /* inflate that block type */
903 return inflate_dynamic();
905 return inflate_stored();
907 return inflate_fixed();
917 /* decompress an inflated entry */
919 int e; /* last block flag */
920 int r; /* result code */
921 unsigned h; /* maximum struct huft's malloc'ed */
924 /* initialize window, bit buffer */
930 /* decompress until the last block */
934 if ((r = inflate_block(&e)) != 0)
940 /* Undo too much lookahead. The next read will be byte aligned so we
941 * can discard unused bits in the last meaningful byte.
948 /* flush out slide */
954 fprintf(stderr, "<%u> ", h);