imgact_gzip.c revision 3353
1/*
2 * Parts of this file are not covered by:
3 * ----------------------------------------------------------------------------
4 * "THE BEER-WARE LICENSE" (Revision 42):
5 * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
6 * can do whatever you want with this stuff. If we meet some day, and you think
7 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
8 * ----------------------------------------------------------------------------
9 *
10 * $Id: imgact_gzip.c,v 1.3 1994/10/04 03:09:13 phk Exp $
11 *
12 * This module handles execution of a.out files which have been run through
13 * "gzip -9".
14 *
15 * For now you need to use exactly this command to compress the binaries:
16 *
17 *		gzip -9 -v < /bin/sh > /tmp/sh
18 *
19 * TODO:
20 *	text-segments should be made R/O after being filled
21 *	is the vm-stuff safe ?
22 * 	should handle the entire header of gzip'ed stuff.
23 *	inflate isn't quite reentrant yet...
24 *	error-handling is a mess...
25 *	so is the rest...
26 */
27
28#include <sys/param.h>
29#include <sys/systm.h>
30#include <sys/resourcevar.h>
31#include <sys/exec.h>
32#include <sys/mman.h>
33#include <sys/malloc.h>
34#include <sys/imgact.h>
35#include <sys/imgact_aout.h>
36#include <sys/kernel.h>
37#include <sys/sysent.h>
38
39#include <vm/vm.h>
40#include <vm/vm_kern.h>
41
42#define WSIZE 0x8000
43
44struct gzip {
45	struct	image_params *ip;
46	struct  exec a_out;
47	int	error;
48	int	where;
49	u_char  *inbuf;
50	u_long	offset;
51	u_long	output;
52	u_long	len;
53	int	idx;
54	u_long	virtual_offset, file_offset, file_end, bss_size;
55        unsigned gz_wp;
56	u_char	*gz_slide;
57};
58
59int inflate __P((struct gzip *));
60
61extern struct sysentvec aout_sysvec;
62
63#define slide (gz->gz_slide)
64#define wp    (gz->gz_wp)
65
66int
67exec_gzip_imgact(iparams)
68	struct image_params *iparams;
69{
70	int error,error2=0;
71	u_char *p = (u_char *) iparams->image_header;
72	struct gzip *gz;
73
74	/* If these four are not OK, it isn't a gzip file */
75	if (p[0] != 0x1f)   return -1;      /* 0    Simply magic	*/
76	if (p[1] != 0x8b)   return -1;      /* 1    Simply magic	*/
77	if (p[2] != 0x08)   return -1;      /* 2    Compression method	*/
78	if (p[9] != 0x03)   return -1;      /* 9    OS compressed on	*/
79
80	/* If this one contains anything but a comment or a filename
81	 * marker, we don't want to chew on it
82	 */
83	if (p[3] & ~(0x18)) return ENOEXEC; /* 3    Flags		*/
84
85	/* These are of no use to us */
86					    /* 4-7  Timestamp		*/
87					    /* 8    Extra flags		*/
88
89	gz = malloc(sizeof *gz,M_GZIP,M_NOWAIT);
90	if (!gz)
91		return ENOMEM;
92	bzero(gz,sizeof *gz); /* waste of time ? */
93
94	gz->gz_slide = malloc(WSIZE,M_TEMP,M_NOWAIT);
95	if (!gz->gz_slide) {
96		free(gz,M_GZIP);
97		return ENOMEM;
98	}
99
100	gz->ip = iparams;
101	gz->error = ENOEXEC;
102	gz->idx = 10;
103
104	if (p[3] & 0x08) {  /* skip a filename */
105	    while (p[gz->idx++])
106		if (gz->idx >= PAGE_SIZE)
107		    goto done;
108	}
109
110	if (p[3] & 0x10) {  /* skip a comment */
111	    while (p[gz->idx++])
112		if (gz->idx >= PAGE_SIZE)
113		    goto done;
114	}
115
116	gz->len = gz->ip->attr->va_size;
117
118	gz->error = 0;
119
120	error = inflate(gz);
121
122	if (gz->inbuf) {
123	    error2 =
124		vm_deallocate(kernel_map, (vm_offset_t)gz->inbuf, PAGE_SIZE);
125	}
126
127	if (gz->error || error || error2) {
128	    printf("Output=%lu ",gz->output);
129	    printf("Inflate_error=%d gz->error=%d error2=%d where=%d\n",
130		error,gz->error,error2,gz->where);
131	    if (gz->error)
132		goto done;
133	    if (error) {
134		gz->error = ENOEXEC;
135		goto done;
136	    }
137	    if (error2) {
138		gz->error = error2;
139		goto done;
140	    }
141	}
142
143    done:
144	error = gz->error;
145	free(gz->gz_slide,M_TEMP);
146	free(gz,M_GZIP);
147	return error;
148}
149
150int
151do_aout_hdr(struct gzip *gz)
152{
153    int error;
154    struct vmspace *vmspace = gz->ip->proc->p_vmspace;
155    u_long vmaddr;
156
157    /*
158     * Set file/virtual offset based on a.out variant.
159     *	We do two cases: host byte order and network byte order
160     *	(for NetBSD compatibility)
161     */
162    switch ((int)(gz->a_out.a_magic & 0xffff)) {
163    case ZMAGIC:
164	gz->virtual_offset = 0;
165	if (gz->a_out.a_text) {
166	    gz->file_offset = NBPG;
167	} else {
168	    /* Bill's "screwball mode" */
169	    gz->file_offset = 0;
170	}
171	break;
172    case QMAGIC:
173	gz->virtual_offset = NBPG;
174	gz->file_offset = 0;
175	break;
176    default:
177	/* NetBSD compatibility */
178	switch ((int)(ntohl(gz->a_out.a_magic) & 0xffff)) {
179	case ZMAGIC:
180	case QMAGIC:
181	    gz->virtual_offset = NBPG;
182	    gz->file_offset = 0;
183	    break;
184	default:
185	    gz->where = __LINE__;
186	    return (-1);
187	}
188    }
189
190    gz->bss_size = roundup(gz->a_out.a_bss, NBPG);
191
192    /*
193     * Check various fields in header for validity/bounds.
194     */
195    if (/* entry point must lay with text region */
196	gz->a_out.a_entry < gz->virtual_offset ||
197	gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
198
199	/* text and data size must each be page rounded */
200	gz->a_out.a_text % NBPG ||
201	gz->a_out.a_data % NBPG) {
202	    gz->where = __LINE__;
203	    return (-1);
204    }
205
206    /*
207     * text/data/bss must not exceed limits
208     */
209    if (/* text can't exceed maximum text size */
210	gz->a_out.a_text > MAXTSIZ ||
211
212	/* data + bss can't exceed maximum data size */
213	gz->a_out.a_data + gz->bss_size > MAXDSIZ ||
214
215	/* data + bss can't exceed rlimit */
216	gz->a_out.a_data + gz->bss_size >
217	    gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
218		    gz->where = __LINE__;
219		    return (ENOMEM);
220    }
221
222    /* Find out how far we should go */
223    gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
224
225    /* copy in arguments and/or environment from old process */
226    error = exec_extract_strings(gz->ip);
227    if (error) {
228	gz->where = __LINE__;
229	return (error);
230    }
231
232    /*
233     * Destroy old process VM and create a new one (with a new stack)
234     */
235    exec_new_vmspace(gz->ip);
236
237    vmaddr = gz->virtual_offset;
238
239    error = vm_mmap(&vmspace->vm_map,           /* map */
240	&vmaddr,                                /* address */
241	gz->a_out.a_text,                      /* size */
242	VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_WRITE,  /* protection */
243	VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_WRITE,
244	MAP_ANON | MAP_FIXED,                /* flags */
245	0,				        /* vnode */
246	0);                                     /* offset */
247
248    if (error) {
249	gz->where = __LINE__;
250	return (error);
251    }
252
253    vmaddr = gz->virtual_offset + gz->a_out.a_text;
254
255    /*
256     * Map data read/write (if text is 0, assume text is in data area
257     *      [Bill's screwball mode])
258     */
259
260    error = vm_mmap(&vmspace->vm_map,
261	&vmaddr,
262	gz->a_out.a_data,
263	VM_PROT_READ | VM_PROT_WRITE | (gz->a_out.a_text ? 0 : VM_PROT_EXECUTE),
264	VM_PROT_ALL, MAP_ANON | MAP_FIXED,
265	0,
266	0);
267
268    if (error) {
269	gz->where = __LINE__;
270	return (error);
271    }
272
273    /*
274     * Allocate demand-zeroed area for uninitialized data
275     * "bss" = 'block started by symbol' - named after the IBM 7090
276     *      instruction of the same name.
277     */
278    vmaddr = gz->virtual_offset + gz->a_out.a_text + gz->a_out.a_data;
279    error = vm_allocate(&vmspace->vm_map, &vmaddr, gz->bss_size, FALSE);
280    if (error) {
281	gz->where = __LINE__;
282	return (error);
283    }
284
285    /* Fill in process VM information */
286    vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
287    vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
288    vmspace->vm_taddr = (caddr_t) gz->virtual_offset;
289    vmspace->vm_daddr = (caddr_t) gz->virtual_offset + gz->a_out.a_text;
290
291    /* Fill in image_params */
292    gz->ip->interpreted = 0;
293    gz->ip->entry_addr = gz->a_out.a_entry;
294
295    gz->ip->proc->p_sysent = &aout_sysvec;
296
297    return 0;
298}
299
300/*
301 * Tell kern_execve.c about it, with a little help from the linker.
302 * Since `const' objects end up in the text segment, TEXT_SET is the
303 * correct directive to use.
304 */
305static const struct execsw gzip_execsw = { exec_gzip_imgact, "gzip" };
306TEXT_SET(execsw_set, gzip_execsw);
307
308/* Stuff to make inflate() work */
309#  define uch u_char
310#  define ush u_short
311#  define ulg u_long
312#  define memzero(dest,len)      bzero(dest,len)
313#  define NOMEMCPY
314#define FPRINTF printf
315
316#define EOF -1
317#define CHECK_EOF
318static int
319NextByte(struct gzip *gz)
320{
321	int error;
322
323	if(gz->idx >= gz->len) {
324	    gz->where = __LINE__;
325	    return EOF;
326	}
327
328	if((!gz->inbuf) || gz->idx >= (gz->offset+PAGE_SIZE)) {
329		if(gz->inbuf) {
330		    error = vm_deallocate(kernel_map,
331		      (vm_offset_t)gz->inbuf, PAGE_SIZE);
332		    if(error) {
333			gz->where = __LINE__;
334			gz->error = error;
335			return EOF;
336		    }
337		}
338
339		gz->offset += PAGE_SIZE;
340
341		error = vm_mmap(kernel_map,             /* map */
342                        (vm_offset_t *)&gz->inbuf,       /* address */
343                        PAGE_SIZE,                      /* size */
344                        VM_PROT_READ,                   /* protection */
345                        VM_PROT_READ,                   /* max protection */
346                        0,                              /* flags */
347                        (caddr_t)gz->ip->vnodep,        /* vnode */
348                        gz->offset);                    /* offset */
349		if(error) {
350		    gz->where = __LINE__;
351		    gz->error = error;
352		    return EOF;
353		}
354
355	}
356	return gz->inbuf[(gz->idx++) - gz->offset];
357}
358
359#define NEXTBYTE NextByte(gz)
360
361static int
362Flush(struct gzip *gz,u_long siz)
363{
364    u_char *p = slide,*q;
365    int i;
366
367    /* First, find a a.out-header */
368    if(gz->output < sizeof gz->a_out) {
369	q = (u_char*) &gz->a_out;
370	i = min(siz,sizeof gz->a_out - gz->output);
371	bcopy(p,q+gz->output,i);
372	gz->output += i;
373	p += i;
374	siz -= i;
375	if(gz->output == sizeof gz->a_out) {
376	    i = do_aout_hdr(gz);
377	    if (i == -1) {
378		gz->where = __LINE__;
379		gz->error = ENOEXEC;
380		return ENOEXEC;
381	    } else if (i) {
382		gz->where = __LINE__;
383		gz->error = i;
384		return ENOEXEC;
385	    }
386	    if(gz->file_offset < sizeof gz->a_out) {
387		q = (u_char*) gz->virtual_offset + gz->output - gz->file_offset;
388		bcopy(&gz->a_out,q,sizeof gz->a_out - gz->file_offset);
389	    }
390	}
391    }
392    if(gz->output >= gz->file_offset && gz->output < gz->file_end) {
393	i = min(siz, gz->file_end - gz->output);
394	q = (u_char*) gz->virtual_offset + gz->output - gz->file_offset;
395	bcopy(p,q,i);
396	gz->output += i;
397	p += i;
398	siz -= i;
399    }
400    gz->output += siz;
401    return 0;
402}
403
404#define FLUSH(x,y) {int foo = Flush(x,y); if (foo) return foo;}
405static
406void *
407myalloc(u_long size)
408{
409	return malloc(size, M_GZIP, M_NOWAIT);
410}
411#define malloc myalloc
412
413static
414void
415myfree(void * ptr)
416{
417	free(ptr,M_GZIP);
418}
419#define free myfree
420
421static int qflag;
422#define Trace(x) /* */
423
424
425/* This came from unzip-5.12.  I have changed it to pass a "gz" pointer
426 * around, thus hopefully making it re-entrant.  Poul-Henningi
427 */
428
429/* inflate.c -- put in the public domain by Mark Adler
430   version c14o, 23 August 1994 */
431
432/* You can do whatever you like with this source file, though I would
433   prefer that if you modify it and redistribute it that you include
434   comments to that effect with your name and the date.  Thank you.
435
436   History:
437   vers    date          who           what
438   ----  ---------  --------------  ------------------------------------
439    a    ~~ Feb 92  M. Adler        used full (large, one-step) lookup table
440    b1   21 Mar 92  M. Adler        first version with partial lookup tables
441    b2   21 Mar 92  M. Adler        fixed bug in fixed-code blocks
442    b3   22 Mar 92  M. Adler        sped up match copies, cleaned up some
443    b4   25 Mar 92  M. Adler        added prototypes; removed window[] (now
444                                    is the responsibility of unzip.h--also
445                                    changed name to slide[]), so needs diffs
446                                    for unzip.c and unzip.h (this allows
447                                    compiling in the small model on MSDOS);
448                                    fixed cast of q in huft_build();
449    b5   26 Mar 92  M. Adler        got rid of unintended macro recursion.
450    b6   27 Mar 92  M. Adler        got rid of nextbyte() routine.  fixed
451                                    bug in inflate_fixed().
452    c1   30 Mar 92  M. Adler        removed lbits, dbits environment variables.
453                                    changed BMAX to 16 for explode.  Removed
454                                    OUTB usage, and replaced it with flush()--
455                                    this was a 20% speed improvement!  Added
456                                    an explode.c (to replace unimplod.c) that
457                                    uses the huft routines here.  Removed
458                                    register union.
459    c2    4 Apr 92  M. Adler        fixed bug for file sizes a multiple of 32k.
460    c3   10 Apr 92  M. Adler        reduced memory of code tables made by
461                                    huft_build significantly (factor of two to
462                                    three).
463    c4   15 Apr 92  M. Adler        added NOMEMCPY do kill use of memcpy().
464                                    worked around a Turbo C optimization bug.
465    c5   21 Apr 92  M. Adler        added the WSIZE #define to allow reducing
466                                    the 32K window size for specialized
467                                    applications.
468    c6   31 May 92  M. Adler        added some typecasts to eliminate warnings
469    c7   27 Jun 92  G. Roelofs      added some more typecasts (444:  MSC bug).
470    c8    5 Oct 92  J-l. Gailly     added ifdef'd code to deal with PKZIP bug.
471    c9    9 Oct 92  M. Adler        removed a memory error message (~line 416).
472    c10  17 Oct 92  G. Roelofs      changed ULONG/UWORD/byte to ulg/ush/uch,
473                                    removed old inflate, renamed inflate_entry
474                                    to inflate, added Mark's fix to a comment.
475   c10.5 14 Dec 92  M. Adler        fix up error messages for incomplete trees.
476    c11   2 Jan 93  M. Adler        fixed bug in detection of incomplete
477                                    tables, and removed assumption that EOB is
478                                    the longest code (bad assumption).
479    c12   3 Jan 93  M. Adler        make tables for fixed blocks only once.
480    c13   5 Jan 93  M. Adler        allow all zero length codes (pkzip 2.04c
481                                    outputs one zero length code for an empty
482                                    distance tree).
483    c14  12 Mar 93  M. Adler        made inflate.c standalone with the
484                                    introduction of inflate.h.
485   c14b  16 Jul 93  G. Roelofs      added (unsigned) typecast to w at 470.
486   c14c  19 Jul 93  J. Bush         changed v[N_MAX], l[288], ll[28x+3x] arrays
487                                    to static for Amiga.
488   c14d  13 Aug 93  J-l. Gailly     de-complicatified Mark's c[*p++]++ thing.
489   c14e   8 Oct 93  G. Roelofs      changed memset() to memzero().
490   c14f  22 Oct 93  G. Roelofs      renamed quietflg to qflag; made Trace()
491                                    conditional; added inflate_free().
492   c14g  28 Oct 93  G. Roelofs      changed l/(lx+1) macro to pointer (Cray bug)
493   c14h   7 Dec 93  C. Ghisler      huft_build() optimizations.
494   c14i   9 Jan 94  A. Verheijen    set fixed_t{d,l} to NULL after freeing;
495                    G. Roelofs      check NEXTBYTE macro for EOF.
496   c14j  23 Jan 94  G. Roelofs      removed Ghisler "optimizations"; ifdef'd
497                                    EOF check.
498   c14k  27 Feb 94  G. Roelofs      added some typecasts to avoid warnings.
499   c14l   9 Apr 94  G. Roelofs      fixed split comments on preprocessor lines
500                                    to avoid bug in Encore compiler.
501   c14m   7 Jul 94  P. Kienitz      modified to allow assembler version of
502                                    inflate_codes() (define ASM_INFLATECODES)
503   c14n  22 Jul 94  G. Roelofs      changed fprintf to FPRINTF for DLL versions
504   c14o  23 Aug 94  C. Spieler      added a newline to a debug statement;
505                    G. Roelofs      added another typecast to avoid MSC warning
506 */
507
508
509/*
510   Inflate deflated (PKZIP's method 8 compressed) data.  The compression
511   method searches for as much of the current string of bytes (up to a
512   length of 258) in the previous 32K bytes.  If it doesn't find any
513   matches (of at least length 3), it codes the next byte.  Otherwise, it
514   codes the length of the matched string and its distance backwards from
515   the current position.  There is a single Huffman code that codes both
516   single bytes (called "literals") and match lengths.  A second Huffman
517   code codes the distance information, which follows a length code.  Each
518   length or distance code actually represents a base value and a number
519   of "extra" (sometimes zero) bits to get to add to the base value.  At
520   the end of each deflated block is a special end-of-block (EOB) literal/
521   length code.  The decoding process is basically: get a literal/length
522   code; if EOB then done; if a literal, emit the decoded byte; if a
523   length then get the distance and emit the referred-to bytes from the
524   sliding window of previously emitted data.
525
526   There are (currently) three kinds of inflate blocks: stored, fixed, and
527   dynamic.  The compressor outputs a chunk of data at a time and decides
528   which method to use on a chunk-by-chunk basis.  A chunk might typically
529   be 32K to 64K, uncompressed.  If the chunk is uncompressible, then the
530   "stored" method is used.  In this case, the bytes are simply stored as
531   is, eight bits per byte, with none of the above coding.  The bytes are
532   preceded by a count, since there is no longer an EOB code.
533
534   If the data is compressible, then either the fixed or dynamic methods
535   are used.  In the dynamic method, the compressed data is preceded by
536   an encoding of the literal/length and distance Huffman codes that are
537   to be used to decode this block.  The representation is itself Huffman
538   coded, and so is preceded by a description of that code.  These code
539   descriptions take up a little space, and so for small blocks, there is
540   a predefined set of codes, called the fixed codes.  The fixed method is
541   used if the block ends up smaller that way (usually for quite small
542   chunks); otherwise the dynamic method is used.  In the latter case, the
543   codes are customized to the probabilities in the current block and so
544   can code it much better than the pre-determined fixed codes can.
545
546   The Huffman codes themselves are decoded using a mutli-level table
547   lookup, in order to maximize the speed of decoding plus the speed of
548   building the decoding tables.  See the comments below that precede the
549   lbits and dbits tuning parameters.
550 */
551
552
553/*
554   Notes beyond the 1.93a appnote.txt:
555
556   1. Distance pointers never point before the beginning of the output
557      stream.
558   2. Distance pointers can point back across blocks, up to 32k away.
559   3. There is an implied maximum of 7 bits for the bit length table and
560      15 bits for the actual data.
561   4. If only one code exists, then it is encoded using one bit.  (Zero
562      would be more efficient, but perhaps a little confusing.)  If two
563      codes exist, they are coded using one bit each (0 and 1).
564   5. There is no way of sending zero distance codes--a dummy must be
565      sent if there are none.  (History: a pre 2.0 version of PKZIP would
566      store blocks with no distance codes, but this was discovered to be
567      too harsh a criterion.)  Valid only for 1.93a.  2.04c does allow
568      zero distance codes, which is sent as one code of zero bits in
569      length.
570   6. There are up to 286 literal/length codes.  Code 256 represents the
571      end-of-block.  Note however that the static length tree defines
572      288 codes just to fill out the Huffman codes.  Codes 286 and 287
573      cannot be used though, since there is no length base or extra bits
574      defined for them.  Similarily, there are up to 30 distance codes.
575      However, static trees define 32 codes (all 5 bits) to fill out the
576      Huffman codes, but the last two had better not show up in the data.
577   7. Unzip can check dynamic Huffman blocks for complete code sets.
578      The exception is that a single code would not be complete (see #4).
579   8. The five bits following the block type is really the number of
580      literal codes sent minus 257.
581   9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
582      (1+6+6).  Therefore, to output three times the length, you output
583      three codes (1+1+1), whereas to output four times the same length,
584      you only need two codes (1+3).  Hmm.
585  10. In the tree reconstruction algorithm, Code = Code + Increment
586      only if BitLength(i) is not zero.  (Pretty obvious.)
587  11. Correction: 4 Bits: # of Bit Length codes - 4     (4 - 19)
588  12. Note: length code 284 can represent 227-258, but length code 285
589      really is 258.  The last length deserves its own, short code
590      since it gets used a lot in very redundant files.  The length
591      258 is special since 258 - 3 (the min match length) is 255.
592  13. The literal/length and distance code bit lengths are read as a
593      single stream of lengths.  It is possible (and advantageous) for
594      a repeat code (16, 17, or 18) to go across the boundary between
595      the two sets of lengths.
596 */
597
598
599#define PKZIP_BUG_WORKAROUND    /* PKZIP 1.93a problem--live with it */
600
601/*
602    inflate.h must supply the uch slide[WSIZE] array and the NEXTBYTE,
603    FLUSH() and memzero macros.  If the window size is not 32K, it
604    should also define WSIZE.  If INFMOD is defined, it can include
605    compiled functions to support the NEXTBYTE and/or FLUSH() macros.
606    There are defaults for NEXTBYTE and FLUSH() below for use as
607    examples of what those functions need to do.  Normally, you would
608    also want FLUSH() to compute a crc on the data.  inflate.h also
609    needs to provide these typedefs:
610
611        typedef unsigned char uch;
612        typedef unsigned short ush;
613        typedef unsigned long ulg;
614
615    This module uses the external functions malloc() and free() (and
616    probably memset() or bzero() in the memzero() macro).  Their
617    prototypes are normally found in <string.h> and <stdlib.h>.
618 */
619#define INFMOD          /* tell inflate.h to include code to be compiled */
620
621/* Huffman code lookup table entry--this entry is four bytes for machines
622   that have 16-bit pointers (e.g. PC's in the small or medium model).
623   Valid extra bits are 0..13.  e == 15 is EOB (end of block), e == 16
624   means that v is a literal, 16 < e < 32 means that v is a pointer to
625   the next table, which codes e - 16 bits, and lastly e == 99 indicates
626   an unused code.  If a code with e == 99 is looked up, this implies an
627   error in the data. */
628struct huft {
629  uch e;                /* number of extra bits or operation */
630  uch b;                /* number of bits in this code or subcode */
631  union {
632    ush n;              /* literal, length base, or distance base */
633    struct huft *t;     /* pointer to next level of table */
634  } v;
635};
636
637
638/* Function prototypes */
639#ifndef OF
640#  ifdef __STDC__
641#    define OF(a) a
642#  else /* !__STDC__ */
643#    define OF(a) ()
644#  endif /* ?__STDC__ */
645#endif
646int huft_build OF((struct gzip *,unsigned *, unsigned, unsigned, ush *, ush *,
647                   struct huft **, int *));
648int huft_free OF((struct gzip *,struct huft *));
649int inflate_codes OF((struct gzip *,struct huft *, struct huft *, int, int));
650int inflate_stored OF((struct gzip *));
651int inflate_fixed OF((struct gzip *));
652int inflate_dynamic OF((struct gzip *));
653int inflate_block OF((struct gzip *,int *));
654int inflate_free OF((struct gzip *));
655
656
657/* The inflate algorithm uses a sliding 32K byte window on the uncompressed
658   stream to find repeated byte strings.  This is implemented here as a
659   circular buffer.  The index is updated simply by incrementing and then
660   and'ing with 0x7fff (32K-1). */
661/* It is left to other modules to supply the 32K area.  It is assumed
662   to be usable as if it were declared "uch slide[32768];" or as just
663   "uch *slide;" and then malloc'ed in the latter case.  The definition
664   must be in unzip.h, included above. */
665
666
667/* Tables for deflate from PKZIP's appnote.txt. */
668static unsigned border[] = {    /* Order of the bit length code lengths */
669        16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
670static ush cplens[] = {         /* Copy lengths for literal codes 257..285 */
671        3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
672        35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
673        /* note: see note #13 above about the 258 in this list. */
674static ush cplext[] = {         /* Extra bits for literal codes 257..285 */
675        0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
676        3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */
677static ush cpdist[] = {         /* Copy offsets for distance codes 0..29 */
678        1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
679        257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
680        8193, 12289, 16385, 24577};
681static ush cpdext[] = {         /* Extra bits for distance codes */
682        0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
683        7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
684        12, 12, 13, 13};
685
686/* And'ing with mask[n] masks the lower n bits */
687ush mask[] = {
688    0x0000,
689    0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
690    0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
691};
692
693
694/* Macros for inflate() bit peeking and grabbing.
695   The usage is:
696
697        NEEDBITS(j)
698        x = b & mask[j];
699        DUMPBITS(j)
700
701   where NEEDBITS makes sure that b has at least j bits in it, and
702   DUMPBITS removes the bits from b.  The macros use the variable k
703   for the number of bits in b.  Normally, b and k are register
704   variables for speed, and are initialized at the begining of a
705   routine that uses these macros from a global bit buffer and count.
706
707   In order to not ask for more bits than there are in the compressed
708   stream, the Huffman tables are constructed to only ask for just
709   enough bits to make up the end-of-block code (value 256).  Then no
710   bytes need to be "returned" to the buffer at the end of the last
711   block.  See the huft_build() routine.
712 */
713
714ulg bb;                         /* bit buffer */
715unsigned bk;                    /* bits in bit buffer */
716
717#ifndef CHECK_EOF
718#  define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE)<<k;k+=8;}}
719#else
720#  define NEEDBITS(n) {while(k<(n)){int c=NEXTBYTE;if(c==EOF)return 1;\
721    b|=((ulg)c)<<k;k+=8;}}
722#endif                      /* Piet Plomp:  change "return 1" to "break" */
723
724#define DUMPBITS(n) {b>>=(n);k-=(n);}
725
726
727/*
728   Huffman code decoding is performed using a multi-level table lookup.
729   The fastest way to decode is to simply build a lookup table whose
730   size is determined by the longest code.  However, the time it takes
731   to build this table can also be a factor if the data being decoded
732   is not very long.  The most common codes are necessarily the
733   shortest codes, so those codes dominate the decoding time, and hence
734   the speed.  The idea is you can have a shorter table that decodes the
735   shorter, more probable codes, and then point to subsidiary tables for
736   the longer codes.  The time it costs to decode the longer codes is
737   then traded against the time it takes to make longer tables.
738
739   This results of this trade are in the variables lbits and dbits
740   below.  lbits is the number of bits the first level table for literal/
741   length codes can decode in one step, and dbits is the same thing for
742   the distance codes.  Subsequent tables are also less than or equal to
743   those sizes.  These values may be adjusted either when all of the
744   codes are shorter than that, in which case the longest code length in
745   bits is used, or when the shortest code is *longer* than the requested
746   table size, in which case the length of the shortest code in bits is
747   used.
748
749   There are two different values for the two tables, since they code a
750   different number of possibilities each.  The literal/length table
751   codes 286 possible values, or in a flat code, a little over eight
752   bits.  The distance table codes 30 possible values, or a little less
753   than five bits, flat.  The optimum values for speed end up being
754   about one bit more than those, so lbits is 8+1 and dbits is 5+1.
755   The optimum values may differ though from machine to machine, and
756   possibly even between compilers.  Your mileage may vary.
757 */
758
759
760int lbits = 9;          /* bits in base literal/length lookup table */
761int dbits = 6;          /* bits in base distance lookup table */
762
763
764/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
765#define BMAX 16         /* maximum bit length of any code (16 for explode) */
766#define N_MAX 288       /* maximum number of codes in any set */
767
768
769unsigned hufts;         /* track memory usage */
770
771
772int huft_build(gz,b, n, s, d, e, t, m)
773struct gzip *gz;
774unsigned *b;            /* code lengths in bits (all assumed <= BMAX) */
775unsigned n;             /* number of codes (assumed <= N_MAX) */
776unsigned s;             /* number of simple-valued codes (0..s-1) */
777ush *d;                 /* list of base values for non-simple codes */
778ush *e;                 /* list of extra bits for non-simple codes */
779struct huft **t;        /* result: starting table */
780int *m;                 /* maximum lookup bits, returns actual */
781/* Given a list of code lengths and a maximum table size, make a set of
782   tables to decode that set of codes.  Return zero on success, one if
783   the given code set is incomplete (the tables are still built in this
784   case), two if the input is invalid (all zero length codes or an
785   oversubscribed set of lengths), and three if not enough memory.
786   The code with value 256 is special, and the tables are constructed
787   so that no bits beyond that code are fetched when that code is
788   decoded. */
789{
790  unsigned a;                   /* counter for codes of length k */
791  unsigned c[BMAX+1];           /* bit length count table */
792  unsigned el;                  /* length of EOB code (value 256) */
793  unsigned f;                   /* i repeats in table every f entries */
794  int g;                        /* maximum code length */
795  int h;                        /* table level */
796  register unsigned i;          /* counter, current code */
797  register unsigned j;          /* counter */
798  register int k;               /* number of bits in current code */
799  int lx[BMAX+1];               /* memory for l[-1..BMAX-1] */
800  int *l = lx+1;                /* stack of bits per table */
801  register unsigned *p;         /* pointer into c[], b[], or v[] */
802  register struct huft *q;      /* points to current table */
803  struct huft r;                /* table entry for structure assignment */
804  struct huft *u[BMAX];         /* table stack */
805  static unsigned v[N_MAX];     /* values in order of bit length */
806  register int w;               /* bits before this table == (l * h) */
807  unsigned x[BMAX+1];           /* bit offsets, then code stack */
808  unsigned *xp;                 /* pointer into x */
809  int y;                        /* number of dummy codes added */
810  unsigned z;                   /* number of entries in current table */
811
812
813  /* Generate counts for each bit length */
814  el = n > 256 ? b[256] : BMAX; /* set length of EOB code, if any */
815  memzero((char *)c, sizeof(c));
816  p = b;  i = n;
817  do {
818    c[*p]++; p++;               /* assume all entries <= BMAX */
819  } while (--i);
820  if (c[0] == n)                /* null input--all zero length codes */
821  {
822    *t = (struct huft *)NULL;
823    *m = 0;
824    return 0;
825  }
826
827
828  /* Find minimum and maximum length, bound *m by those */
829  for (j = 1; j <= BMAX; j++)
830    if (c[j])
831      break;
832  k = j;                        /* minimum code length */
833  if ((unsigned)*m < j)
834    *m = j;
835  for (i = BMAX; i; i--)
836    if (c[i])
837      break;
838  g = i;                        /* maximum code length */
839  if ((unsigned)*m > i)
840    *m = i;
841
842
843  /* Adjust last length count to fill out codes, if needed */
844  for (y = 1 << j; j < i; j++, y <<= 1)
845    if ((y -= c[j]) < 0)
846      return 2;                 /* bad input: more codes than bits */
847  if ((y -= c[i]) < 0)
848    return 2;
849  c[i] += y;
850
851
852  /* Generate starting offsets into the value table for each length */
853  x[1] = j = 0;
854  p = c + 1;  xp = x + 2;
855  while (--i) {                 /* note that i == g from above */
856    *xp++ = (j += *p++);
857  }
858
859
860  /* Make a table of values in order of bit lengths */
861  p = b;  i = 0;
862  do {
863    if ((j = *p++) != 0)
864      v[x[j]++] = i;
865  } while (++i < n);
866
867
868  /* Generate the Huffman codes and for each, make the table entries */
869  x[0] = i = 0;                 /* first Huffman code is zero */
870  p = v;                        /* grab values in bit order */
871  h = -1;                       /* no tables yet--level -1 */
872  w = l[-1] = 0;                /* no bits decoded yet */
873  u[0] = (struct huft *)NULL;   /* just to keep compilers happy */
874  q = (struct huft *)NULL;      /* ditto */
875  z = 0;                        /* ditto */
876
877  /* go through the bit lengths (k already is bits in shortest code) */
878  for (; k <= g; k++)
879  {
880    a = c[k];
881    while (a--)
882    {
883      /* here i is the Huffman code of length k bits for value *p */
884      /* make tables up to required level */
885      while (k > w + l[h])
886      {
887        w += l[h++];            /* add bits already decoded */
888
889        /* compute minimum size table less than or equal to *m bits */
890        z = (z = g - w) > (unsigned)*m ? *m : z;        /* upper limit */
891        if ((f = 1 << (j = k - w)) > a + 1)     /* try a k-w bit table */
892        {                       /* too few codes for k-w bit table */
893          f -= a + 1;           /* deduct codes from patterns left */
894          xp = c + k;
895          while (++j < z)       /* try smaller tables up to z bits */
896          {
897            if ((f <<= 1) <= *++xp)
898              break;            /* enough codes to use up j bits */
899            f -= *xp;           /* else deduct codes from patterns */
900          }
901        }
902        if ((unsigned)w + j > el && (unsigned)w < el)
903          j = el - w;           /* make EOB code end at table */
904        z = 1 << j;             /* table entries for j-bit table */
905        l[h] = j;               /* set table size in stack */
906
907        /* allocate and link in new table */
908        if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) ==
909            (struct huft *)NULL)
910        {
911          if (h)
912            huft_free(gz,u[0]);
913          return 3;             /* not enough memory */
914        }
915        hufts += z + 1;         /* track memory usage */
916        *t = q + 1;             /* link to list for huft_free() */
917        *(t = &(q->v.t)) = (struct huft *)NULL;
918        u[h] = ++q;             /* table starts after link */
919
920        /* connect to last table, if there is one */
921        if (h)
922        {
923          x[h] = i;             /* save pattern for backing up */
924          r.b = (uch)l[h-1];    /* bits to dump before this table */
925          r.e = (uch)(16 + j);  /* bits in this table */
926          r.v.t = q;            /* pointer to this table */
927          j = (i & ((1 << w) - 1)) >> (w - l[h-1]);
928          u[h-1][j] = r;        /* connect to last table */
929        }
930      }
931
932      /* set up table entry in r */
933      r.b = (uch)(k - w);
934      if (p >= v + n)
935        r.e = 99;               /* out of values--invalid code */
936      else if (*p < s)
937      {
938        r.e = (uch)(*p < 256 ? 16 : 15);    /* 256 is end-of-block code */
939        r.v.n = *p++;           /* simple code is just the value */
940      }
941      else
942      {
943        r.e = (uch)e[*p - s];   /* non-simple--look up in lists */
944        r.v.n = d[*p++ - s];
945      }
946
947      /* fill code-like entries with r */
948      f = 1 << (k - w);
949      for (j = i >> w; j < z; j += f)
950        q[j] = r;
951
952      /* backwards increment the k-bit code i */
953      for (j = 1 << (k - 1); i & j; j >>= 1)
954        i ^= j;
955      i ^= j;
956
957      /* backup over finished tables */
958      while ((i & ((1 << w) - 1)) != x[h])
959        w -= l[--h];            /* don't need to update q */
960    }
961  }
962
963
964  /* return actual size of base table */
965  *m = l[0];
966
967
968  /* Return true (1) if we were given an incomplete table */
969  return y != 0 && g != 1;
970}
971
972
973
974int huft_free(gz,t)
975struct gzip *gz;
976struct huft *t;         /* table to free */
977/* Free the malloc'ed tables built by huft_build(), which makes a linked
978   list of the tables it made, with the links in a dummy first entry of
979   each table. */
980{
981  register struct huft *p, *q;
982
983
984  /* Go through linked list, freeing from the malloced (t[-1]) address. */
985  p = t;
986  while (p != (struct huft *)NULL)
987  {
988    q = (--p)->v.t;
989    free(p);
990    p = q;
991  }
992  return 0;
993}
994
995
996
997#ifdef ASM_INFLATECODES
998#  define inflate_codes(tl,td,bl,bd)  flate_codes(tl,td,bl,bd,(uch *)slide)
999   int flate_codes OF((struct huft *, struct huft *, int, int, uch *));
1000
1001#else
1002
1003int inflate_codes(gz,tl, td, bl, bd)
1004struct gzip *gz;
1005struct huft *tl, *td;   /* literal/length and distance decoder tables */
1006int bl, bd;             /* number of bits decoded by tl[] and td[] */
1007/* inflate (decompress) the codes in a deflated (compressed) block.
1008   Return an error code or zero if it all goes ok. */
1009{
1010  register unsigned e;  /* table entry flag/number of extra bits */
1011  unsigned n, d;        /* length and index for copy */
1012  unsigned w;           /* current window position */
1013  struct huft *t;       /* pointer to table entry */
1014  unsigned ml, md;      /* masks for bl and bd bits */
1015  register ulg b;       /* bit buffer */
1016  register unsigned k;  /* number of bits in bit buffer */
1017
1018
1019  /* make local copies of globals */
1020  b = bb;                       /* initialize bit buffer */
1021  k = bk;
1022  w = wp;                       /* initialize window position */
1023
1024
1025  /* inflate the coded data */
1026  ml = mask[bl];           /* precompute masks for speed */
1027  md = mask[bd];
1028  while (1)                     /* do until end of block */
1029  {
1030    NEEDBITS((unsigned)bl)
1031    if ((e = (t = tl + ((unsigned)b & ml))->e) > 16)
1032      do {
1033        if (e == 99)
1034          return 1;
1035        DUMPBITS(t->b)
1036        e -= 16;
1037        NEEDBITS(e)
1038      } while ((e = (t = t->v.t + ((unsigned)b & mask[e]))->e) > 16);
1039    DUMPBITS(t->b)
1040    if (e == 16)                /* then it's a literal */
1041    {
1042      slide[w++] = (uch)t->v.n;
1043      if (w == WSIZE)
1044      {
1045        FLUSH(gz,w);
1046        w = 0;
1047      }
1048    }
1049    else                        /* it's an EOB or a length */
1050    {
1051      /* exit if end of block */
1052      if (e == 15)
1053        break;
1054
1055      /* get length of block to copy */
1056      NEEDBITS(e)
1057      n = t->v.n + ((unsigned)b & mask[e]);
1058      DUMPBITS(e);
1059
1060      /* decode distance of block to copy */
1061      NEEDBITS((unsigned)bd)
1062      if ((e = (t = td + ((unsigned)b & md))->e) > 16)
1063        do {
1064          if (e == 99)
1065            return 1;
1066          DUMPBITS(t->b)
1067          e -= 16;
1068          NEEDBITS(e)
1069        } while ((e = (t = t->v.t + ((unsigned)b & mask[e]))->e) > 16);
1070      DUMPBITS(t->b)
1071      NEEDBITS(e)
1072      d = w - t->v.n - ((unsigned)b & mask[e]);
1073      DUMPBITS(e)
1074
1075      /* do the copy */
1076      do {
1077        n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e);
1078#ifndef NOMEMCPY
1079        if (w - d >= e)         /* (this test assumes unsigned comparison) */
1080        {
1081          memcpy(slide + w, slide + d, e);
1082          w += e;
1083          d += e;
1084        }
1085        else                      /* do it slow to avoid memcpy() overlap */
1086#endif /* !NOMEMCPY */
1087          do {
1088            slide[w++] = slide[d++];
1089          } while (--e);
1090        if (w == WSIZE)
1091        {
1092          FLUSH(gz,w);
1093          w = 0;
1094        }
1095      } while (n);
1096    }
1097  }
1098
1099
1100  /* restore the globals from the locals */
1101  wp = w;                       /* restore global window pointer */
1102  bb = b;                       /* restore global bit buffer */
1103  bk = k;
1104
1105
1106  /* done */
1107  return 0;
1108}
1109
1110#endif /* ASM_INFLATECODES */
1111
1112
1113
1114int inflate_stored(gz)
1115struct gzip *gz;
1116/* "decompress" an inflated type 0 (stored) block. */
1117{
1118  unsigned n;           /* number of bytes in block */
1119  unsigned w;           /* current window position */
1120  register ulg b;       /* bit buffer */
1121  register unsigned k;  /* number of bits in bit buffer */
1122
1123
1124  /* make local copies of globals */
1125  Trace((stderr, "\nstored block"));
1126  b = bb;                       /* initialize bit buffer */
1127  k = bk;
1128  w = wp;                       /* initialize window position */
1129
1130
1131  /* go to byte boundary */
1132  n = k & 7;
1133  DUMPBITS(n);
1134
1135
1136  /* get the length and its complement */
1137  NEEDBITS(16)
1138  n = ((unsigned)b & 0xffff);
1139  DUMPBITS(16)
1140  NEEDBITS(16)
1141  if (n != (unsigned)((~b) & 0xffff))
1142    return 1;                   /* error in compressed data */
1143  DUMPBITS(16)
1144
1145
1146  /* read and output the compressed data */
1147  while (n--)
1148  {
1149    NEEDBITS(8)
1150    slide[w++] = (uch)b;
1151    if (w == WSIZE)
1152    {
1153      FLUSH(gz,w);
1154      w = 0;
1155    }
1156    DUMPBITS(8)
1157  }
1158
1159
1160  /* restore the globals from the locals */
1161  wp = w;                       /* restore global window pointer */
1162  bb = b;                       /* restore global bit buffer */
1163  bk = k;
1164  return 0;
1165}
1166
1167
1168/* Globals for literal tables (built once) */
1169struct huft *fixed_tl = (struct huft *)NULL;
1170struct huft *fixed_td;
1171int fixed_bl, fixed_bd;
1172
1173int inflate_fixed(gz)
1174struct gzip *gz;
1175/* decompress an inflated type 1 (fixed Huffman codes) block.  We should
1176   either replace this with a custom decoder, or at least precompute the
1177   Huffman tables. */
1178{
1179  /* if first time, set up tables for fixed blocks */
1180  Trace((stderr, "\nliteral block"));
1181  if (fixed_tl == (struct huft *)NULL)
1182  {
1183    int i;                /* temporary variable */
1184    static unsigned l[288]; /* length list for huft_build */
1185
1186    /* literal table */
1187    for (i = 0; i < 144; i++)
1188      l[i] = 8;
1189    for (; i < 256; i++)
1190      l[i] = 9;
1191    for (; i < 280; i++)
1192      l[i] = 7;
1193    for (; i < 288; i++)          /* make a complete, but wrong code set */
1194      l[i] = 8;
1195    fixed_bl = 7;
1196    if ((i = huft_build(gz,l, 288, 257, cplens, cplext,
1197                        &fixed_tl, &fixed_bl)) != 0)
1198    {
1199      fixed_tl = (struct huft *)NULL;
1200      return i;
1201    }
1202
1203    /* distance table */
1204    for (i = 0; i < 30; i++)      /* make an incomplete code set */
1205      l[i] = 5;
1206    fixed_bd = 5;
1207    if ((i = huft_build(gz,l, 30, 0, cpdist, cpdext, &fixed_td, &fixed_bd)) > 1)
1208    {
1209      huft_free(gz,fixed_tl);
1210      fixed_tl = (struct huft *)NULL;
1211      return i;
1212    }
1213  }
1214
1215
1216  /* decompress until an end-of-block code */
1217  return inflate_codes(gz,fixed_tl, fixed_td, fixed_bl, fixed_bd) != 0;
1218}
1219
1220
1221
1222int inflate_dynamic(gz)
1223struct gzip *gz;
1224/* decompress an inflated type 2 (dynamic Huffman codes) block. */
1225{
1226  int i;                /* temporary variables */
1227  unsigned j;
1228  unsigned l;           /* last length */
1229  unsigned m;           /* mask for bit lengths table */
1230  unsigned n;           /* number of lengths to get */
1231  struct huft *tl;      /* literal/length code table */
1232  struct huft *td;      /* distance code table */
1233  int bl;               /* lookup bits for tl */
1234  int bd;               /* lookup bits for td */
1235  unsigned nb;          /* number of bit length codes */
1236  unsigned nl;          /* number of literal/length codes */
1237  unsigned nd;          /* number of distance codes */
1238#ifdef PKZIP_BUG_WORKAROUND
1239  static unsigned ll[288+32]; /* literal/length and distance code lengths */
1240#else
1241  static unsigned ll[286+30]; /* literal/length and distance code lengths */
1242#endif
1243  register ulg b;       /* bit buffer */
1244  register unsigned k;  /* number of bits in bit buffer */
1245
1246
1247  /* make local bit buffer */
1248  Trace((stderr, "\ndynamic block"));
1249  b = bb;
1250  k = bk;
1251
1252
1253  /* read in table lengths */
1254  NEEDBITS(5)
1255  nl = 257 + ((unsigned)b & 0x1f);      /* number of literal/length codes */
1256  DUMPBITS(5)
1257  NEEDBITS(5)
1258  nd = 1 + ((unsigned)b & 0x1f);        /* number of distance codes */
1259  DUMPBITS(5)
1260  NEEDBITS(4)
1261  nb = 4 + ((unsigned)b & 0xf);         /* number of bit length codes */
1262  DUMPBITS(4)
1263#ifdef PKZIP_BUG_WORKAROUND
1264  if (nl > 288 || nd > 32)
1265#else
1266  if (nl > 286 || nd > 30)
1267#endif
1268    return 1;                   /* bad lengths */
1269
1270
1271  /* read in bit-length-code lengths */
1272  for (j = 0; j < nb; j++)
1273  {
1274    NEEDBITS(3)
1275    ll[border[j]] = (unsigned)b & 7;
1276    DUMPBITS(3)
1277  }
1278  for (; j < 19; j++)
1279    ll[border[j]] = 0;
1280
1281
1282  /* build decoding table for trees--single level, 7 bit lookup */
1283  bl = 7;
1284  if ((i = huft_build(gz,ll, 19, 19, NULL, NULL, &tl, &bl)) != 0)
1285  {
1286    if (i == 1)
1287      huft_free(gz,tl);
1288    return i;                   /* incomplete code set */
1289  }
1290
1291
1292  /* read in literal and distance code lengths */
1293  n = nl + nd;
1294  m = mask[bl];
1295  i = l = 0;
1296  while ((unsigned)i < n)
1297  {
1298    NEEDBITS((unsigned)bl)
1299    j = (td = tl + ((unsigned)b & m))->b;
1300    DUMPBITS(j)
1301    j = td->v.n;
1302    if (j < 16)                 /* length of code in bits (0..15) */
1303      ll[i++] = l = j;          /* save last length in l */
1304    else if (j == 16)           /* repeat last length 3 to 6 times */
1305    {
1306      NEEDBITS(2)
1307      j = 3 + ((unsigned)b & 3);
1308      DUMPBITS(2)
1309      if ((unsigned)i + j > n)
1310        return 1;
1311      while (j--)
1312        ll[i++] = l;
1313    }
1314    else if (j == 17)           /* 3 to 10 zero length codes */
1315    {
1316      NEEDBITS(3)
1317      j = 3 + ((unsigned)b & 7);
1318      DUMPBITS(3)
1319      if ((unsigned)i + j > n)
1320        return 1;
1321      while (j--)
1322        ll[i++] = 0;
1323      l = 0;
1324    }
1325    else                        /* j == 18: 11 to 138 zero length codes */
1326    {
1327      NEEDBITS(7)
1328      j = 11 + ((unsigned)b & 0x7f);
1329      DUMPBITS(7)
1330      if ((unsigned)i + j > n)
1331        return 1;
1332      while (j--)
1333        ll[i++] = 0;
1334      l = 0;
1335    }
1336  }
1337
1338
1339  /* free decoding table for trees */
1340  huft_free(gz,tl);
1341
1342
1343  /* restore the global bit buffer */
1344  bb = b;
1345  bk = k;
1346
1347
1348  /* build the decoding tables for literal/length and distance codes */
1349  bl = lbits;
1350  if ((i = huft_build(gz,ll, nl, 257, cplens, cplext, &tl, &bl)) != 0)
1351  {
1352    if (i == 1 && !qflag) {
1353      FPRINTF( "(incomplete l-tree)  ");
1354      huft_free(gz,tl);
1355    }
1356    return i;                   /* incomplete code set */
1357  }
1358  bd = dbits;
1359  if ((i = huft_build(gz,ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0)
1360  {
1361    if (i == 1 && !qflag) {
1362      FPRINTF( "(incomplete d-tree)  ");
1363#ifdef PKZIP_BUG_WORKAROUND
1364      i = 0;
1365    }
1366#else
1367      huft_free(gz,td);
1368    }
1369    huft_free(gz,tl);
1370    return i;                   /* incomplete code set */
1371#endif
1372  }
1373
1374
1375  /* decompress until an end-of-block code */
1376  if (inflate_codes(gz,tl, td, bl, bd))
1377    return 1;
1378
1379
1380  /* free the decoding tables, return */
1381  huft_free(gz,tl);
1382  huft_free(gz,td);
1383  return 0;
1384}
1385
1386
1387
1388int inflate_block(gz,e)
1389struct gzip *gz;
1390int *e;                 /* last block flag */
1391/* decompress an inflated block */
1392{
1393  unsigned t;           /* block type */
1394  register ulg b;       /* bit buffer */
1395  register unsigned k;  /* number of bits in bit buffer */
1396
1397
1398  /* make local bit buffer */
1399  b = bb;
1400  k = bk;
1401
1402
1403  /* read in last block bit */
1404  NEEDBITS(1)
1405  *e = (int)b & 1;
1406  DUMPBITS(1)
1407
1408
1409  /* read in block type */
1410  NEEDBITS(2)
1411  t = (unsigned)b & 3;
1412  DUMPBITS(2)
1413
1414
1415  /* restore the global bit buffer */
1416  bb = b;
1417  bk = k;
1418
1419
1420  /* inflate that block type */
1421  if (t == 2)
1422    return inflate_dynamic(gz);
1423  if (t == 0)
1424    return inflate_stored(gz);
1425  if (t == 1)
1426    return inflate_fixed(gz);
1427
1428
1429  /* bad block type */
1430  return 2;
1431}
1432
1433
1434
1435int inflate(gz)
1436struct gzip *gz;
1437/* decompress an inflated entry */
1438{
1439  int e;                /* last block flag */
1440  int r;                /* result code */
1441  unsigned h;           /* maximum struct huft's malloc'ed */
1442
1443
1444  /* initialize window, bit buffer */
1445  wp = 0;
1446  bk = 0;
1447  bb = 0;
1448
1449
1450  /* decompress until the last block */
1451  h = 0;
1452  do {
1453    hufts = 0;
1454    if ((r = inflate_block(gz,&e)) != 0)
1455      return r;
1456    if (hufts > h)
1457      h = hufts;
1458  } while (!e);
1459
1460
1461  /* flush out slide */
1462  FLUSH(gz,wp);
1463
1464
1465  /* return success */
1466  Trace((stderr, "\n%u bytes in Huffman tables (%d/entry)\n",
1467         h * sizeof(struct huft), sizeof(struct huft)));
1468  return 0;
1469}
1470
1471
1472
1473int inflate_free(gz)
1474struct gzip *gz;
1475{
1476  if (fixed_tl != (struct huft *)NULL)
1477  {
1478    huft_free(gz,fixed_td);
1479    huft_free(gz,fixed_tl);
1480    fixed_td = fixed_tl = (struct huft *)NULL;
1481  }
1482  return 0;
1483}
1484