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0001 #define DEBG(x)
0002 #define DEBG1(x)
0003 /* inflate.c -- Not copyrighted 1992 by Mark Adler
0004    version c10p1, 10 January 1993 */
0005 
0006 /* 
0007  * Adapted for booting Linux by Hannu Savolainen 1993
0008  * based on gzip-1.0.3 
0009  *
0010  * Nicolas Pitre <nico@fluxnic.net>, 1999/04/14 :
0011  *   Little mods for all variable to reside either into rodata or bss segments
0012  *   by marking constant variables with 'const' and initializing all the others
0013  *   at run-time only.  This allows for the kernel uncompressor to run
0014  *   directly from Flash or ROM memory on embedded systems.
0015  */
0016 
0017 /*
0018    Inflate deflated (PKZIP's method 8 compressed) data.  The compression
0019    method searches for as much of the current string of bytes (up to a
0020    length of 258) in the previous 32 K bytes.  If it doesn't find any
0021    matches (of at least length 3), it codes the next byte.  Otherwise, it
0022    codes the length of the matched string and its distance backwards from
0023    the current position.  There is a single Huffman code that codes both
0024    single bytes (called "literals") and match lengths.  A second Huffman
0025    code codes the distance information, which follows a length code.  Each
0026    length or distance code actually represents a base value and a number
0027    of "extra" (sometimes zero) bits to get to add to the base value.  At
0028    the end of each deflated block is a special end-of-block (EOB) literal/
0029    length code.  The decoding process is basically: get a literal/length
0030    code; if EOB then done; if a literal, emit the decoded byte; if a
0031    length then get the distance and emit the referred-to bytes from the
0032    sliding window of previously emitted data.
0033 
0034    There are (currently) three kinds of inflate blocks: stored, fixed, and
0035    dynamic.  The compressor deals with some chunk of data at a time, and
0036    decides which method to use on a chunk-by-chunk basis.  A chunk might
0037    typically be 32 K or 64 K.  If the chunk is incompressible, then the
0038    "stored" method is used.  In this case, the bytes are simply stored as
0039    is, eight bits per byte, with none of the above coding.  The bytes are
0040    preceded by a count, since there is no longer an EOB code.
0041 
0042    If the data is compressible, then either the fixed or dynamic methods
0043    are used.  In the dynamic method, the compressed data is preceded by
0044    an encoding of the literal/length and distance Huffman codes that are
0045    to be used to decode this block.  The representation is itself Huffman
0046    coded, and so is preceded by a description of that code.  These code
0047    descriptions take up a little space, and so for small blocks, there is
0048    a predefined set of codes, called the fixed codes.  The fixed method is
0049    used if the block codes up smaller that way (usually for quite small
0050    chunks), otherwise the dynamic method is used.  In the latter case, the
0051    codes are customized to the probabilities in the current block, and so
0052    can code it much better than the pre-determined fixed codes.
0053  
0054    The Huffman codes themselves are decoded using a multi-level table
0055    lookup, in order to maximize the speed of decoding plus the speed of
0056    building the decoding tables.  See the comments below that precede the
0057    lbits and dbits tuning parameters.
0058  */
0059 
0060 
0061 /*
0062    Notes beyond the 1.93a appnote.txt:
0063 
0064    1. Distance pointers never point before the beginning of the output
0065       stream.
0066    2. Distance pointers can point back across blocks, up to 32k away.
0067    3. There is an implied maximum of 7 bits for the bit length table and
0068       15 bits for the actual data.
0069    4. If only one code exists, then it is encoded using one bit.  (Zero
0070       would be more efficient, but perhaps a little confusing.)  If two
0071       codes exist, they are coded using one bit each (0 and 1).
0072    5. There is no way of sending zero distance codes--a dummy must be
0073       sent if there are none.  (History: a pre 2.0 version of PKZIP would
0074       store blocks with no distance codes, but this was discovered to be
0075       too harsh a criterion.)  Valid only for 1.93a.  2.04c does allow
0076       zero distance codes, which is sent as one code of zero bits in
0077       length.
0078    6. There are up to 286 literal/length codes.  Code 256 represents the
0079       end-of-block.  Note however that the static length tree defines
0080       288 codes just to fill out the Huffman codes.  Codes 286 and 287
0081       cannot be used though, since there is no length base or extra bits
0082       defined for them.  Similarly, there are up to 30 distance codes.
0083       However, static trees define 32 codes (all 5 bits) to fill out the
0084       Huffman codes, but the last two had better not show up in the data.
0085    7. Unzip can check dynamic Huffman blocks for complete code sets.
0086       The exception is that a single code would not be complete (see #4).
0087    8. The five bits following the block type is really the number of
0088       literal codes sent minus 257.
0089    9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
0090       (1+6+6).  Therefore, to output three times the length, you output
0091       three codes (1+1+1), whereas to output four times the same length,
0092       you only need two codes (1+3).  Hmm.
0093   10. In the tree reconstruction algorithm, Code = Code + Increment
0094       only if BitLength(i) is not zero.  (Pretty obvious.)
0095   11. Correction: 4 Bits: # of Bit Length codes - 4     (4 - 19)
0096   12. Note: length code 284 can represent 227-258, but length code 285
0097       really is 258.  The last length deserves its own, short code
0098       since it gets used a lot in very redundant files.  The length
0099       258 is special since 258 - 3 (the min match length) is 255.
0100   13. The literal/length and distance code bit lengths are read as a
0101       single stream of lengths.  It is possible (and advantageous) for
0102       a repeat code (16, 17, or 18) to go across the boundary between
0103       the two sets of lengths.
0104  */
0105 #include <linux/compiler.h>
0106 #ifdef NO_INFLATE_MALLOC
0107 #include <linux/slab.h>
0108 #endif
0109 
0110 #ifdef RCSID
0111 static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #";
0112 #endif
0113 
0114 #ifndef STATIC
0115 
0116 #if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H)
0117 #  include <sys/types.h>
0118 #  include <stdlib.h>
0119 #endif
0120 
0121 #include "gzip.h"
0122 #define STATIC
0123 #endif /* !STATIC */
0124 
0125 #ifndef INIT
0126 #define INIT
0127 #endif
0128     
0129 #define slide window
0130 
0131 /* Huffman code lookup table entry--this entry is four bytes for machines
0132    that have 16-bit pointers (e.g. PC's in the small or medium model).
0133    Valid extra bits are 0..13.  e == 15 is EOB (end of block), e == 16
0134    means that v is a literal, 16 < e < 32 means that v is a pointer to
0135    the next table, which codes e - 16 bits, and lastly e == 99 indicates
0136    an unused code.  If a code with e == 99 is looked up, this implies an
0137    error in the data. */
0138 struct huft {
0139   uch e;                /* number of extra bits or operation */
0140   uch b;                /* number of bits in this code or subcode */
0141   union {
0142     ush n;              /* literal, length base, or distance base */
0143     struct huft *t;     /* pointer to next level of table */
0144   } v;
0145 };
0146 
0147 
0148 /* Function prototypes */
0149 STATIC int INIT huft_build OF((unsigned *, unsigned, unsigned, 
0150         const ush *, const ush *, struct huft **, int *));
0151 STATIC int INIT huft_free OF((struct huft *));
0152 STATIC int INIT inflate_codes OF((struct huft *, struct huft *, int, int));
0153 STATIC int INIT inflate_stored OF((void));
0154 STATIC int INIT inflate_fixed OF((void));
0155 STATIC int INIT inflate_dynamic OF((void));
0156 STATIC int INIT inflate_block OF((int *));
0157 STATIC int INIT inflate OF((void));
0158 
0159 
0160 /* The inflate algorithm uses a sliding 32 K byte window on the uncompressed
0161    stream to find repeated byte strings.  This is implemented here as a
0162    circular buffer.  The index is updated simply by incrementing and then
0163    ANDing with 0x7fff (32K-1). */
0164 /* It is left to other modules to supply the 32 K area.  It is assumed
0165    to be usable as if it were declared "uch slide[32768];" or as just
0166    "uch *slide;" and then malloc'ed in the latter case.  The definition
0167    must be in unzip.h, included above. */
0168 /* unsigned wp;             current position in slide */
0169 #define wp outcnt
0170 #define flush_output(w) (wp=(w),flush_window())
0171 
0172 /* Tables for deflate from PKZIP's appnote.txt. */
0173 static const unsigned border[] = {    /* Order of the bit length code lengths */
0174         16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
0175 static const ush cplens[] = {         /* Copy lengths for literal codes 257..285 */
0176         3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
0177         35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
0178         /* note: see note #13 above about the 258 in this list. */
0179 static const ush cplext[] = {         /* Extra bits for literal codes 257..285 */
0180         0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
0181         3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */
0182 static const ush cpdist[] = {         /* Copy offsets for distance codes 0..29 */
0183         1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
0184         257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
0185         8193, 12289, 16385, 24577};
0186 static const ush cpdext[] = {         /* Extra bits for distance codes */
0187         0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
0188         7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
0189         12, 12, 13, 13};
0190 
0191 
0192 
0193 /* Macros for inflate() bit peeking and grabbing.
0194    The usage is:
0195    
0196         NEEDBITS(j)
0197         x = b & mask_bits[j];
0198         DUMPBITS(j)
0199 
0200    where NEEDBITS makes sure that b has at least j bits in it, and
0201    DUMPBITS removes the bits from b.  The macros use the variable k
0202    for the number of bits in b.  Normally, b and k are register
0203    variables for speed, and are initialized at the beginning of a
0204    routine that uses these macros from a global bit buffer and count.
0205 
0206    If we assume that EOB will be the longest code, then we will never
0207    ask for bits with NEEDBITS that are beyond the end of the stream.
0208    So, NEEDBITS should not read any more bytes than are needed to
0209    meet the request.  Then no bytes need to be "returned" to the buffer
0210    at the end of the last block.
0211 
0212    However, this assumption is not true for fixed blocks--the EOB code
0213    is 7 bits, but the other literal/length codes can be 8 or 9 bits.
0214    (The EOB code is shorter than other codes because fixed blocks are
0215    generally short.  So, while a block always has an EOB, many other
0216    literal/length codes have a significantly lower probability of
0217    showing up at all.)  However, by making the first table have a
0218    lookup of seven bits, the EOB code will be found in that first
0219    lookup, and so will not require that too many bits be pulled from
0220    the stream.
0221  */
0222 
0223 STATIC ulg bb;                         /* bit buffer */
0224 STATIC unsigned bk;                    /* bits in bit buffer */
0225 
0226 STATIC const ush mask_bits[] = {
0227     0x0000,
0228     0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
0229     0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
0230 };
0231 
0232 #define NEXTBYTE()  ({ int v = get_byte(); if (v < 0) goto underrun; (uch)v; })
0233 #define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}}
0234 #define DUMPBITS(n) {b>>=(n);k-=(n);}
0235 
0236 #ifndef NO_INFLATE_MALLOC
0237 /* A trivial malloc implementation, adapted from
0238  *  malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
0239  */
0240 
0241 static unsigned long malloc_ptr;
0242 static int malloc_count;
0243 
0244 static void *malloc(int size)
0245 {
0246        void *p;
0247 
0248        if (size < 0)
0249         error("Malloc error");
0250        if (!malloc_ptr)
0251         malloc_ptr = free_mem_ptr;
0252 
0253        malloc_ptr = (malloc_ptr + 3) & ~3;     /* Align */
0254 
0255        p = (void *)malloc_ptr;
0256        malloc_ptr += size;
0257 
0258        if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr)
0259         error("Out of memory");
0260 
0261        malloc_count++;
0262        return p;
0263 }
0264 
0265 static void free(void *where)
0266 {
0267        malloc_count--;
0268        if (!malloc_count)
0269         malloc_ptr = free_mem_ptr;
0270 }
0271 #else
0272 #define malloc(a) kmalloc(a, GFP_KERNEL)
0273 #define free(a) kfree(a)
0274 #endif
0275 
0276 /*
0277    Huffman code decoding is performed using a multi-level table lookup.
0278    The fastest way to decode is to simply build a lookup table whose
0279    size is determined by the longest code.  However, the time it takes
0280    to build this table can also be a factor if the data being decoded
0281    is not very long.  The most common codes are necessarily the
0282    shortest codes, so those codes dominate the decoding time, and hence
0283    the speed.  The idea is you can have a shorter table that decodes the
0284    shorter, more probable codes, and then point to subsidiary tables for
0285    the longer codes.  The time it costs to decode the longer codes is
0286    then traded against the time it takes to make longer tables.
0287 
0288    This results of this trade are in the variables lbits and dbits
0289    below.  lbits is the number of bits the first level table for literal/
0290    length codes can decode in one step, and dbits is the same thing for
0291    the distance codes.  Subsequent tables are also less than or equal to
0292    those sizes.  These values may be adjusted either when all of the
0293    codes are shorter than that, in which case the longest code length in
0294    bits is used, or when the shortest code is *longer* than the requested
0295    table size, in which case the length of the shortest code in bits is
0296    used.
0297 
0298    There are two different values for the two tables, since they code a
0299    different number of possibilities each.  The literal/length table
0300    codes 286 possible values, or in a flat code, a little over eight
0301    bits.  The distance table codes 30 possible values, or a little less
0302    than five bits, flat.  The optimum values for speed end up being
0303    about one bit more than those, so lbits is 8+1 and dbits is 5+1.
0304    The optimum values may differ though from machine to machine, and
0305    possibly even between compilers.  Your mileage may vary.
0306  */
0307 
0308 
0309 STATIC const int lbits = 9;          /* bits in base literal/length lookup table */
0310 STATIC const int dbits = 6;          /* bits in base distance lookup table */
0311 
0312 
0313 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
0314 #define BMAX 16         /* maximum bit length of any code (16 for explode) */
0315 #define N_MAX 288       /* maximum number of codes in any set */
0316 
0317 
0318 STATIC unsigned hufts;         /* track memory usage */
0319 
0320 
0321 STATIC int INIT huft_build(
0322     unsigned *b,            /* code lengths in bits (all assumed <= BMAX) */
0323     unsigned n,             /* number of codes (assumed <= N_MAX) */
0324     unsigned s,             /* number of simple-valued codes (0..s-1) */
0325     const ush *d,           /* list of base values for non-simple codes */
0326     const ush *e,           /* list of extra bits for non-simple codes */
0327     struct huft **t,        /* result: starting table */
0328     int *m                  /* maximum lookup bits, returns actual */
0329     )
0330 /* Given a list of code lengths and a maximum table size, make a set of
0331    tables to decode that set of codes.  Return zero on success, one if
0332    the given code set is incomplete (the tables are still built in this
0333    case), two if the input is invalid (all zero length codes or an
0334    oversubscribed set of lengths), and three if not enough memory. */
0335 {
0336   unsigned a;                   /* counter for codes of length k */
0337   unsigned f;                   /* i repeats in table every f entries */
0338   int g;                        /* maximum code length */
0339   int h;                        /* table level */
0340   register unsigned i;          /* counter, current code */
0341   register unsigned j;          /* counter */
0342   register int k;               /* number of bits in current code */
0343   int l;                        /* bits per table (returned in m) */
0344   register unsigned *p;         /* pointer into c[], b[], or v[] */
0345   register struct huft *q;      /* points to current table */
0346   struct huft r;                /* table entry for structure assignment */
0347   register int w;               /* bits before this table == (l * h) */
0348   unsigned *xp;                 /* pointer into x */
0349   int y;                        /* number of dummy codes added */
0350   unsigned z;                   /* number of entries in current table */
0351   struct {
0352     unsigned c[BMAX+1];           /* bit length count table */
0353     struct huft *u[BMAX];         /* table stack */
0354     unsigned v[N_MAX];            /* values in order of bit length */
0355     unsigned x[BMAX+1];           /* bit offsets, then code stack */
0356   } *stk;
0357   unsigned *c, *v, *x;
0358   struct huft **u;
0359   int ret;
0360 
0361 DEBG("huft1 ");
0362 
0363   stk = malloc(sizeof(*stk));
0364   if (stk == NULL)
0365     return 3;           /* out of memory */
0366 
0367   c = stk->c;
0368   v = stk->v;
0369   x = stk->x;
0370   u = stk->u;
0371 
0372   /* Generate counts for each bit length */
0373   memzero(stk->c, sizeof(stk->c));
0374   p = b;  i = n;
0375   do {
0376     Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"), 
0377         n-i, *p));
0378     c[*p]++;                    /* assume all entries <= BMAX */
0379     p++;                      /* Can't combine with above line (Solaris bug) */
0380   } while (--i);
0381   if (c[0] == n)                /* null input--all zero length codes */
0382   {
0383     *t = (struct huft *)NULL;
0384     *m = 0;
0385     ret = 2;
0386     goto out;
0387   }
0388 
0389 DEBG("huft2 ");
0390 
0391   /* Find minimum and maximum length, bound *m by those */
0392   l = *m;
0393   for (j = 1; j <= BMAX; j++)
0394     if (c[j])
0395       break;
0396   k = j;                        /* minimum code length */
0397   if ((unsigned)l < j)
0398     l = j;
0399   for (i = BMAX; i; i--)
0400     if (c[i])
0401       break;
0402   g = i;                        /* maximum code length */
0403   if ((unsigned)l > i)
0404     l = i;
0405   *m = l;
0406 
0407 DEBG("huft3 ");
0408 
0409   /* Adjust last length count to fill out codes, if needed */
0410   for (y = 1 << j; j < i; j++, y <<= 1)
0411     if ((y -= c[j]) < 0) {
0412       ret = 2;                 /* bad input: more codes than bits */
0413       goto out;
0414     }
0415   if ((y -= c[i]) < 0) {
0416     ret = 2;
0417     goto out;
0418   }
0419   c[i] += y;
0420 
0421 DEBG("huft4 ");
0422 
0423   /* Generate starting offsets into the value table for each length */
0424   x[1] = j = 0;
0425   p = c + 1;  xp = x + 2;
0426   while (--i) {                 /* note that i == g from above */
0427     *xp++ = (j += *p++);
0428   }
0429 
0430 DEBG("huft5 ");
0431 
0432   /* Make a table of values in order of bit lengths */
0433   p = b;  i = 0;
0434   do {
0435     if ((j = *p++) != 0)
0436       v[x[j]++] = i;
0437   } while (++i < n);
0438   n = x[g];                   /* set n to length of v */
0439 
0440 DEBG("h6 ");
0441 
0442   /* Generate the Huffman codes and for each, make the table entries */
0443   x[0] = i = 0;                 /* first Huffman code is zero */
0444   p = v;                        /* grab values in bit order */
0445   h = -1;                       /* no tables yet--level -1 */
0446   w = -l;                       /* bits decoded == (l * h) */
0447   u[0] = (struct huft *)NULL;   /* just to keep compilers happy */
0448   q = (struct huft *)NULL;      /* ditto */
0449   z = 0;                        /* ditto */
0450 DEBG("h6a ");
0451 
0452   /* go through the bit lengths (k already is bits in shortest code) */
0453   for (; k <= g; k++)
0454   {
0455 DEBG("h6b ");
0456     a = c[k];
0457     while (a--)
0458     {
0459 DEBG("h6b1 ");
0460       /* here i is the Huffman code of length k bits for value *p */
0461       /* make tables up to required level */
0462       while (k > w + l)
0463       {
0464 DEBG1("1 ");
0465         h++;
0466         w += l;                 /* previous table always l bits */
0467 
0468         /* compute minimum size table less than or equal to l bits */
0469         z = (z = g - w) > (unsigned)l ? l : z;  /* upper limit on table size */
0470         if ((f = 1 << (j = k - w)) > a + 1)     /* try a k-w bit table */
0471         {                       /* too few codes for k-w bit table */
0472 DEBG1("2 ");
0473           f -= a + 1;           /* deduct codes from patterns left */
0474           xp = c + k;
0475           if (j < z)
0476             while (++j < z)       /* try smaller tables up to z bits */
0477             {
0478               if ((f <<= 1) <= *++xp)
0479                 break;            /* enough codes to use up j bits */
0480               f -= *xp;           /* else deduct codes from patterns */
0481             }
0482         }
0483 DEBG1("3 ");
0484         z = 1 << j;             /* table entries for j-bit table */
0485 
0486         /* allocate and link in new table */
0487         if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) ==
0488             (struct huft *)NULL)
0489         {
0490           if (h)
0491             huft_free(u[0]);
0492           ret = 3;             /* not enough memory */
0493       goto out;
0494         }
0495 DEBG1("4 ");
0496         hufts += z + 1;         /* track memory usage */
0497         *t = q + 1;             /* link to list for huft_free() */
0498         *(t = &(q->v.t)) = (struct huft *)NULL;
0499         u[h] = ++q;             /* table starts after link */
0500 
0501 DEBG1("5 ");
0502         /* connect to last table, if there is one */
0503         if (h)
0504         {
0505           x[h] = i;             /* save pattern for backing up */
0506           r.b = (uch)l;         /* bits to dump before this table */
0507           r.e = (uch)(16 + j);  /* bits in this table */
0508           r.v.t = q;            /* pointer to this table */
0509           j = i >> (w - l);     /* (get around Turbo C bug) */
0510           u[h-1][j] = r;        /* connect to last table */
0511         }
0512 DEBG1("6 ");
0513       }
0514 DEBG("h6c ");
0515 
0516       /* set up table entry in r */
0517       r.b = (uch)(k - w);
0518       if (p >= v + n)
0519         r.e = 99;               /* out of values--invalid code */
0520       else if (*p < s)
0521       {
0522         r.e = (uch)(*p < 256 ? 16 : 15);    /* 256 is end-of-block code */
0523         r.v.n = (ush)(*p);             /* simple code is just the value */
0524     p++;                           /* one compiler does not like *p++ */
0525       }
0526       else
0527       {
0528         r.e = (uch)e[*p - s];   /* non-simple--look up in lists */
0529         r.v.n = d[*p++ - s];
0530       }
0531 DEBG("h6d ");
0532 
0533       /* fill code-like entries with r */
0534       f = 1 << (k - w);
0535       for (j = i >> w; j < z; j += f)
0536         q[j] = r;
0537 
0538       /* backwards increment the k-bit code i */
0539       for (j = 1 << (k - 1); i & j; j >>= 1)
0540         i ^= j;
0541       i ^= j;
0542 
0543       /* backup over finished tables */
0544       while ((i & ((1 << w) - 1)) != x[h])
0545       {
0546         h--;                    /* don't need to update q */
0547         w -= l;
0548       }
0549 DEBG("h6e ");
0550     }
0551 DEBG("h6f ");
0552   }
0553 
0554 DEBG("huft7 ");
0555 
0556   /* Return true (1) if we were given an incomplete table */
0557   ret = y != 0 && g != 1;
0558 
0559   out:
0560   free(stk);
0561   return ret;
0562 }
0563 
0564 
0565 
0566 STATIC int INIT huft_free(
0567     struct huft *t         /* table to free */
0568     )
0569 /* Free the malloc'ed tables built by huft_build(), which makes a linked
0570    list of the tables it made, with the links in a dummy first entry of
0571    each table. */
0572 {
0573   register struct huft *p, *q;
0574 
0575 
0576   /* Go through linked list, freeing from the malloced (t[-1]) address. */
0577   p = t;
0578   while (p != (struct huft *)NULL)
0579   {
0580     q = (--p)->v.t;
0581     free((char*)p);
0582     p = q;
0583   } 
0584   return 0;
0585 }
0586 
0587 
0588 STATIC int INIT inflate_codes(
0589     struct huft *tl,    /* literal/length decoder tables */
0590     struct huft *td,    /* distance decoder tables */
0591     int bl,             /* number of bits decoded by tl[] */
0592     int bd              /* number of bits decoded by td[] */
0593     )
0594 /* inflate (decompress) the codes in a deflated (compressed) block.
0595    Return an error code or zero if it all goes ok. */
0596 {
0597   register unsigned e;  /* table entry flag/number of extra bits */
0598   unsigned n, d;        /* length and index for copy */
0599   unsigned w;           /* current window position */
0600   struct huft *t;       /* pointer to table entry */
0601   unsigned ml, md;      /* masks for bl and bd bits */
0602   register ulg b;       /* bit buffer */
0603   register unsigned k;  /* number of bits in bit buffer */
0604 
0605 
0606   /* make local copies of globals */
0607   b = bb;                       /* initialize bit buffer */
0608   k = bk;
0609   w = wp;                       /* initialize window position */
0610 
0611   /* inflate the coded data */
0612   ml = mask_bits[bl];           /* precompute masks for speed */
0613   md = mask_bits[bd];
0614   for (;;)                      /* do until end of block */
0615   {
0616     NEEDBITS((unsigned)bl)
0617     if ((e = (t = tl + ((unsigned)b & ml))->e) > 16)
0618       do {
0619         if (e == 99)
0620           return 1;
0621         DUMPBITS(t->b)
0622         e -= 16;
0623         NEEDBITS(e)
0624       } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16);
0625     DUMPBITS(t->b)
0626     if (e == 16)                /* then it's a literal */
0627     {
0628       slide[w++] = (uch)t->v.n;
0629       Tracevv((stderr, "%c", slide[w-1]));
0630       if (w == WSIZE)
0631       {
0632         flush_output(w);
0633         w = 0;
0634       }
0635     }
0636     else                        /* it's an EOB or a length */
0637     {
0638       /* exit if end of block */
0639       if (e == 15)
0640         break;
0641 
0642       /* get length of block to copy */
0643       NEEDBITS(e)
0644       n = t->v.n + ((unsigned)b & mask_bits[e]);
0645       DUMPBITS(e);
0646 
0647       /* decode distance of block to copy */
0648       NEEDBITS((unsigned)bd)
0649       if ((e = (t = td + ((unsigned)b & md))->e) > 16)
0650         do {
0651           if (e == 99)
0652             return 1;
0653           DUMPBITS(t->b)
0654           e -= 16;
0655           NEEDBITS(e)
0656         } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16);
0657       DUMPBITS(t->b)
0658       NEEDBITS(e)
0659       d = w - t->v.n - ((unsigned)b & mask_bits[e]);
0660       DUMPBITS(e)
0661       Tracevv((stderr,"\\[%d,%d]", w-d, n));
0662 
0663       /* do the copy */
0664       do {
0665         n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e);
0666 #if !defined(NOMEMCPY) && !defined(DEBUG)
0667         if (w - d >= e)         /* (this test assumes unsigned comparison) */
0668         {
0669           memcpy(slide + w, slide + d, e);
0670           w += e;
0671           d += e;
0672         }
0673         else                      /* do it slow to avoid memcpy() overlap */
0674 #endif /* !NOMEMCPY */
0675           do {
0676             slide[w++] = slide[d++];
0677         Tracevv((stderr, "%c", slide[w-1]));
0678           } while (--e);
0679         if (w == WSIZE)
0680         {
0681           flush_output(w);
0682           w = 0;
0683         }
0684       } while (n);
0685     }
0686   }
0687 
0688 
0689   /* restore the globals from the locals */
0690   wp = w;                       /* restore global window pointer */
0691   bb = b;                       /* restore global bit buffer */
0692   bk = k;
0693 
0694   /* done */
0695   return 0;
0696 
0697  underrun:
0698   return 4;         /* Input underrun */
0699 }
0700 
0701 
0702 
0703 STATIC int INIT inflate_stored(void)
0704 /* "decompress" an inflated type 0 (stored) block. */
0705 {
0706   unsigned n;           /* number of bytes in block */
0707   unsigned w;           /* current window position */
0708   register ulg b;       /* bit buffer */
0709   register unsigned k;  /* number of bits in bit buffer */
0710 
0711 DEBG("<stor");
0712 
0713   /* make local copies of globals */
0714   b = bb;                       /* initialize bit buffer */
0715   k = bk;
0716   w = wp;                       /* initialize window position */
0717 
0718 
0719   /* go to byte boundary */
0720   n = k & 7;
0721   DUMPBITS(n);
0722 
0723 
0724   /* get the length and its complement */
0725   NEEDBITS(16)
0726   n = ((unsigned)b & 0xffff);
0727   DUMPBITS(16)
0728   NEEDBITS(16)
0729   if (n != (unsigned)((~b) & 0xffff))
0730     return 1;                   /* error in compressed data */
0731   DUMPBITS(16)
0732 
0733 
0734   /* read and output the compressed data */
0735   while (n--)
0736   {
0737     NEEDBITS(8)
0738     slide[w++] = (uch)b;
0739     if (w == WSIZE)
0740     {
0741       flush_output(w);
0742       w = 0;
0743     }
0744     DUMPBITS(8)
0745   }
0746 
0747 
0748   /* restore the globals from the locals */
0749   wp = w;                       /* restore global window pointer */
0750   bb = b;                       /* restore global bit buffer */
0751   bk = k;
0752 
0753   DEBG(">");
0754   return 0;
0755 
0756  underrun:
0757   return 4;         /* Input underrun */
0758 }
0759 
0760 
0761 /*
0762  * We use `noinline' here to prevent gcc-3.5 from using too much stack space
0763  */
0764 STATIC int noinline INIT inflate_fixed(void)
0765 /* decompress an inflated type 1 (fixed Huffman codes) block.  We should
0766    either replace this with a custom decoder, or at least precompute the
0767    Huffman tables. */
0768 {
0769   int i;                /* temporary variable */
0770   struct huft *tl;      /* literal/length code table */
0771   struct huft *td;      /* distance code table */
0772   int bl;               /* lookup bits for tl */
0773   int bd;               /* lookup bits for td */
0774   unsigned *l;          /* length list for huft_build */
0775 
0776 DEBG("<fix");
0777 
0778   l = malloc(sizeof(*l) * 288);
0779   if (l == NULL)
0780     return 3;           /* out of memory */
0781 
0782   /* set up literal table */
0783   for (i = 0; i < 144; i++)
0784     l[i] = 8;
0785   for (; i < 256; i++)
0786     l[i] = 9;
0787   for (; i < 280; i++)
0788     l[i] = 7;
0789   for (; i < 288; i++)          /* make a complete, but wrong code set */
0790     l[i] = 8;
0791   bl = 7;
0792   if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
0793     free(l);
0794     return i;
0795   }
0796 
0797   /* set up distance table */
0798   for (i = 0; i < 30; i++)      /* make an incomplete code set */
0799     l[i] = 5;
0800   bd = 5;
0801   if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1)
0802   {
0803     huft_free(tl);
0804     free(l);
0805 
0806     DEBG(">");
0807     return i;
0808   }
0809 
0810 
0811   /* decompress until an end-of-block code */
0812   if (inflate_codes(tl, td, bl, bd)) {
0813     free(l);
0814     return 1;
0815   }
0816 
0817   /* free the decoding tables, return */
0818   free(l);
0819   huft_free(tl);
0820   huft_free(td);
0821   return 0;
0822 }
0823 
0824 
0825 /*
0826  * We use `noinline' here to prevent gcc-3.5 from using too much stack space
0827  */
0828 STATIC int noinline INIT inflate_dynamic(void)
0829 /* decompress an inflated type 2 (dynamic Huffman codes) block. */
0830 {
0831   int i;                /* temporary variables */
0832   unsigned j;
0833   unsigned l;           /* last length */
0834   unsigned m;           /* mask for bit lengths table */
0835   unsigned n;           /* number of lengths to get */
0836   struct huft *tl;      /* literal/length code table */
0837   struct huft *td;      /* distance code table */
0838   int bl;               /* lookup bits for tl */
0839   int bd;               /* lookup bits for td */
0840   unsigned nb;          /* number of bit length codes */
0841   unsigned nl;          /* number of literal/length codes */
0842   unsigned nd;          /* number of distance codes */
0843   unsigned *ll;         /* literal/length and distance code lengths */
0844   register ulg b;       /* bit buffer */
0845   register unsigned k;  /* number of bits in bit buffer */
0846   int ret;
0847 
0848 DEBG("<dyn");
0849 
0850 #ifdef PKZIP_BUG_WORKAROUND
0851   ll = malloc(sizeof(*ll) * (288+32));  /* literal/length and distance code lengths */
0852 #else
0853   ll = malloc(sizeof(*ll) * (286+30));  /* literal/length and distance code lengths */
0854 #endif
0855 
0856   if (ll == NULL)
0857     return 1;
0858 
0859   /* make local bit buffer */
0860   b = bb;
0861   k = bk;
0862 
0863 
0864   /* read in table lengths */
0865   NEEDBITS(5)
0866   nl = 257 + ((unsigned)b & 0x1f);      /* number of literal/length codes */
0867   DUMPBITS(5)
0868   NEEDBITS(5)
0869   nd = 1 + ((unsigned)b & 0x1f);        /* number of distance codes */
0870   DUMPBITS(5)
0871   NEEDBITS(4)
0872   nb = 4 + ((unsigned)b & 0xf);         /* number of bit length codes */
0873   DUMPBITS(4)
0874 #ifdef PKZIP_BUG_WORKAROUND
0875   if (nl > 288 || nd > 32)
0876 #else
0877   if (nl > 286 || nd > 30)
0878 #endif
0879   {
0880     ret = 1;             /* bad lengths */
0881     goto out;
0882   }
0883 
0884 DEBG("dyn1 ");
0885 
0886   /* read in bit-length-code lengths */
0887   for (j = 0; j < nb; j++)
0888   {
0889     NEEDBITS(3)
0890     ll[border[j]] = (unsigned)b & 7;
0891     DUMPBITS(3)
0892   }
0893   for (; j < 19; j++)
0894     ll[border[j]] = 0;
0895 
0896 DEBG("dyn2 ");
0897 
0898   /* build decoding table for trees--single level, 7 bit lookup */
0899   bl = 7;
0900   if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0)
0901   {
0902     if (i == 1)
0903       huft_free(tl);
0904     ret = i;                   /* incomplete code set */
0905     goto out;
0906   }
0907 
0908 DEBG("dyn3 ");
0909 
0910   /* read in literal and distance code lengths */
0911   n = nl + nd;
0912   m = mask_bits[bl];
0913   i = l = 0;
0914   while ((unsigned)i < n)
0915   {
0916     NEEDBITS((unsigned)bl)
0917     j = (td = tl + ((unsigned)b & m))->b;
0918     DUMPBITS(j)
0919     j = td->v.n;
0920     if (j < 16)                 /* length of code in bits (0..15) */
0921       ll[i++] = l = j;          /* save last length in l */
0922     else if (j == 16)           /* repeat last length 3 to 6 times */
0923     {
0924       NEEDBITS(2)
0925       j = 3 + ((unsigned)b & 3);
0926       DUMPBITS(2)
0927       if ((unsigned)i + j > n) {
0928         ret = 1;
0929     goto out;
0930       }
0931       while (j--)
0932         ll[i++] = l;
0933     }
0934     else if (j == 17)           /* 3 to 10 zero length codes */
0935     {
0936       NEEDBITS(3)
0937       j = 3 + ((unsigned)b & 7);
0938       DUMPBITS(3)
0939       if ((unsigned)i + j > n) {
0940         ret = 1;
0941     goto out;
0942       }
0943       while (j--)
0944         ll[i++] = 0;
0945       l = 0;
0946     }
0947     else                        /* j == 18: 11 to 138 zero length codes */
0948     {
0949       NEEDBITS(7)
0950       j = 11 + ((unsigned)b & 0x7f);
0951       DUMPBITS(7)
0952       if ((unsigned)i + j > n) {
0953         ret = 1;
0954     goto out;
0955       }
0956       while (j--)
0957         ll[i++] = 0;
0958       l = 0;
0959     }
0960   }
0961 
0962 DEBG("dyn4 ");
0963 
0964   /* free decoding table for trees */
0965   huft_free(tl);
0966 
0967 DEBG("dyn5 ");
0968 
0969   /* restore the global bit buffer */
0970   bb = b;
0971   bk = k;
0972 
0973 DEBG("dyn5a ");
0974 
0975   /* build the decoding tables for literal/length and distance codes */
0976   bl = lbits;
0977   if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0)
0978   {
0979 DEBG("dyn5b ");
0980     if (i == 1) {
0981       error("incomplete literal tree");
0982       huft_free(tl);
0983     }
0984     ret = i;                   /* incomplete code set */
0985     goto out;
0986   }
0987 DEBG("dyn5c ");
0988   bd = dbits;
0989   if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0)
0990   {
0991 DEBG("dyn5d ");
0992     if (i == 1) {
0993       error("incomplete distance tree");
0994 #ifdef PKZIP_BUG_WORKAROUND
0995       i = 0;
0996     }
0997 #else
0998       huft_free(td);
0999     }
1000     huft_free(tl);
1001     ret = i;                   /* incomplete code set */
1002     goto out;
1003 #endif
1004   }
1005 
1006 DEBG("dyn6 ");
1007 
1008   /* decompress until an end-of-block code */
1009   if (inflate_codes(tl, td, bl, bd)) {
1010     ret = 1;
1011     goto out;
1012   }
1013 
1014 DEBG("dyn7 ");
1015 
1016   /* free the decoding tables, return */
1017   huft_free(tl);
1018   huft_free(td);
1019 
1020   DEBG(">");
1021   ret = 0;
1022 out:
1023   free(ll);
1024   return ret;
1025 
1026 underrun:
1027   ret = 4;          /* Input underrun */
1028   goto out;
1029 }
1030 
1031 
1032 
1033 STATIC int INIT inflate_block(
1034     int *e                  /* last block flag */
1035     )
1036 /* decompress an inflated block */
1037 {
1038   unsigned t;           /* block type */
1039   register ulg b;       /* bit buffer */
1040   register unsigned k;  /* number of bits in bit buffer */
1041 
1042   DEBG("<blk");
1043 
1044   /* make local bit buffer */
1045   b = bb;
1046   k = bk;
1047 
1048 
1049   /* read in last block bit */
1050   NEEDBITS(1)
1051   *e = (int)b & 1;
1052   DUMPBITS(1)
1053 
1054 
1055   /* read in block type */
1056   NEEDBITS(2)
1057   t = (unsigned)b & 3;
1058   DUMPBITS(2)
1059 
1060 
1061   /* restore the global bit buffer */
1062   bb = b;
1063   bk = k;
1064 
1065   /* inflate that block type */
1066   if (t == 2)
1067     return inflate_dynamic();
1068   if (t == 0)
1069     return inflate_stored();
1070   if (t == 1)
1071     return inflate_fixed();
1072 
1073   DEBG(">");
1074 
1075   /* bad block type */
1076   return 2;
1077 
1078  underrun:
1079   return 4;         /* Input underrun */
1080 }
1081 
1082 
1083 
1084 STATIC int INIT inflate(void)
1085 /* decompress an inflated entry */
1086 {
1087   int e;                /* last block flag */
1088   int r;                /* result code */
1089   unsigned h;           /* maximum struct huft's malloc'ed */
1090 
1091   /* initialize window, bit buffer */
1092   wp = 0;
1093   bk = 0;
1094   bb = 0;
1095 
1096 
1097   /* decompress until the last block */
1098   h = 0;
1099   do {
1100     hufts = 0;
1101 #ifdef ARCH_HAS_DECOMP_WDOG
1102     arch_decomp_wdog();
1103 #endif
1104     r = inflate_block(&e);
1105     if (r)
1106         return r;
1107     if (hufts > h)
1108       h = hufts;
1109   } while (!e);
1110 
1111   /* Undo too much lookahead. The next read will be byte aligned so we
1112    * can discard unused bits in the last meaningful byte.
1113    */
1114   while (bk >= 8) {
1115     bk -= 8;
1116     inptr--;
1117   }
1118 
1119   /* flush out slide */
1120   flush_output(wp);
1121 
1122 
1123   /* return success */
1124 #ifdef DEBUG
1125   fprintf(stderr, "<%u> ", h);
1126 #endif /* DEBUG */
1127   return 0;
1128 }
1129 
1130 /**********************************************************************
1131  *
1132  * The following are support routines for inflate.c
1133  *
1134  **********************************************************************/
1135 
1136 static ulg crc_32_tab[256];
1137 static ulg crc;     /* initialized in makecrc() so it'll reside in bss */
1138 #define CRC_VALUE (crc ^ 0xffffffffUL)
1139 
1140 /*
1141  * Code to compute the CRC-32 table. Borrowed from 
1142  * gzip-1.0.3/makecrc.c.
1143  */
1144 
1145 static void INIT
1146 makecrc(void)
1147 {
1148 /* Not copyrighted 1990 Mark Adler  */
1149 
1150   unsigned long c;      /* crc shift register */
1151   unsigned long e;      /* polynomial exclusive-or pattern */
1152   int i;                /* counter for all possible eight bit values */
1153   int k;                /* byte being shifted into crc apparatus */
1154 
1155   /* terms of polynomial defining this crc (except x^32): */
1156   static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
1157 
1158   /* Make exclusive-or pattern from polynomial */
1159   e = 0;
1160   for (i = 0; i < sizeof(p)/sizeof(int); i++)
1161     e |= 1L << (31 - p[i]);
1162 
1163   crc_32_tab[0] = 0;
1164 
1165   for (i = 1; i < 256; i++)
1166   {
1167     c = 0;
1168     for (k = i | 256; k != 1; k >>= 1)
1169     {
1170       c = c & 1 ? (c >> 1) ^ e : c >> 1;
1171       if (k & 1)
1172         c ^= e;
1173     }
1174     crc_32_tab[i] = c;
1175   }
1176 
1177   /* this is initialized here so this code could reside in ROM */
1178   crc = (ulg)0xffffffffUL; /* shift register contents */
1179 }
1180 
1181 /* gzip flag byte */
1182 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
1183 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
1184 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
1185 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
1186 #define COMMENT      0x10 /* bit 4 set: file comment present */
1187 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
1188 #define RESERVED     0xC0 /* bit 6,7:   reserved */
1189 
1190 /*
1191  * Do the uncompression!
1192  */
1193 static int INIT gunzip(void)
1194 {
1195     uch flags;
1196     unsigned char magic[2]; /* magic header */
1197     char method;
1198     ulg orig_crc = 0;       /* original crc */
1199     ulg orig_len = 0;       /* original uncompressed length */
1200     int res;
1201 
1202     magic[0] = NEXTBYTE();
1203     magic[1] = NEXTBYTE();
1204     method   = NEXTBYTE();
1205 
1206     if (magic[0] != 037 ||
1207     ((magic[1] != 0213) && (magic[1] != 0236))) {
1208         error("bad gzip magic numbers");
1209         return -1;
1210     }
1211 
1212     /* We only support method #8, DEFLATED */
1213     if (method != 8)  {
1214         error("internal error, invalid method");
1215         return -1;
1216     }
1217 
1218     flags  = (uch)get_byte();
1219     if ((flags & ENCRYPTED) != 0) {
1220         error("Input is encrypted");
1221         return -1;
1222     }
1223     if ((flags & CONTINUATION) != 0) {
1224         error("Multi part input");
1225         return -1;
1226     }
1227     if ((flags & RESERVED) != 0) {
1228         error("Input has invalid flags");
1229         return -1;
1230     }
1231     NEXTBYTE(); /* Get timestamp */
1232     NEXTBYTE();
1233     NEXTBYTE();
1234     NEXTBYTE();
1235 
1236     (void)NEXTBYTE();  /* Ignore extra flags for the moment */
1237     (void)NEXTBYTE();  /* Ignore OS type for the moment */
1238 
1239     if ((flags & EXTRA_FIELD) != 0) {
1240         unsigned len = (unsigned)NEXTBYTE();
1241         len |= ((unsigned)NEXTBYTE())<<8;
1242         while (len--) (void)NEXTBYTE();
1243     }
1244 
1245     /* Get original file name if it was truncated */
1246     if ((flags & ORIG_NAME) != 0) {
1247         /* Discard the old name */
1248         while (NEXTBYTE() != 0) /* null */ ;
1249     } 
1250 
1251     /* Discard file comment if any */
1252     if ((flags & COMMENT) != 0) {
1253         while (NEXTBYTE() != 0) /* null */ ;
1254     }
1255 
1256     /* Decompress */
1257     if ((res = inflate())) {
1258         switch (res) {
1259         case 0:
1260             break;
1261         case 1:
1262             error("invalid compressed format (err=1)");
1263             break;
1264         case 2:
1265             error("invalid compressed format (err=2)");
1266             break;
1267         case 3:
1268             error("out of memory");
1269             break;
1270         case 4:
1271             error("out of input data");
1272             break;
1273         default:
1274             error("invalid compressed format (other)");
1275         }
1276         return -1;
1277     }
1278         
1279     /* Get the crc and original length */
1280     /* crc32  (see algorithm.doc)
1281      * uncompressed input size modulo 2^32
1282      */
1283     orig_crc = (ulg) NEXTBYTE();
1284     orig_crc |= (ulg) NEXTBYTE() << 8;
1285     orig_crc |= (ulg) NEXTBYTE() << 16;
1286     orig_crc |= (ulg) NEXTBYTE() << 24;
1287     
1288     orig_len = (ulg) NEXTBYTE();
1289     orig_len |= (ulg) NEXTBYTE() << 8;
1290     orig_len |= (ulg) NEXTBYTE() << 16;
1291     orig_len |= (ulg) NEXTBYTE() << 24;
1292     
1293     /* Validate decompression */
1294     if (orig_crc != CRC_VALUE) {
1295         error("crc error");
1296         return -1;
1297     }
1298     if (orig_len != bytes_out) {
1299         error("length error");
1300         return -1;
1301     }
1302     return 0;
1303 
1304  underrun:          /* NEXTBYTE() goto's here if needed */
1305     error("out of input data");
1306     return -1;
1307 }
1308 
1309