#define DEBG(x)
#define DEBG1(x)
/*
 * inflate.c -- Not copyrighted 1992 by Mark Adler
 * version c10p1, 10 January 1993
 */

/*
 * Adapted for booting Linux by Hannu Savolainen 1993
 * based on gzip-1.0.3
 *
 * Nicolas Pitre <nico@cam.org>, 1999/04/14 :
 *   Little mods for all variable to reside either into rodata or bss segments
 *   by marking constant variables with 'const' and initializing all the others
 *   at run-time only.  This allows for the kernel uncompressor to run
 *   directly from Flash or ROM memory on embedded systems.
 */

/*
 * Inflate deflated (PKZIP's method 8 compressed) data.  The compression
 * method searches for as much of the current string of bytes (up to a
 * length of 258) in the previous 32 K bytes.  If it doesn't find any
 * matches (of at least length 3), it codes the next byte.  Otherwise, it
 * codes the length of the matched string and its distance backwards from
 * the current position.  There is a single Huffman code that codes both
 * single bytes (called "literals") and match lengths.  A second Huffman
 * code codes the distance information, which follows a length code.  Each
 * length or distance code actually represents a base value and a number
 * of "extra" (sometimes zero) bits to get to add to the base value.  At
 * the end of each deflated block is a special end-of-block (EOB) literal/
 * length code.  The decoding process is basically: get a literal/length
 * code; if EOB then done; if a literal, emit the decoded byte; if a
 * length then get the distance and emit the referred-to bytes from the
 * sliding window of previously emitted data.
 *
 * There are (currently) three kinds of inflate blocks: stored, fixed, and
 * dynamic.  The compressor deals with some chunk of data at a time, and
 * decides which method to use on a chunk-by-chunk basis.  A chunk might
 * typically be 32 K or 64 K.  If the chunk is incompressible, then the
 * "stored" method is used.  In this case, the bytes are simply stored as
 * is, eight bits per byte, with none of the above coding.  The bytes are
 * preceded by a count, since there is no longer an EOB code.
 *
 * If the data is compressible, then either the fixed or dynamic methods
 * are used.  In the dynamic method, the compressed data is preceded by
 * an encoding of the literal/length and distance Huffman codes that are
 * to be used to decode this block.  The representation is itself Huffman
 * coded, and so is preceded by a description of that code.  These code
 * descriptions take up a little space, and so for small blocks, there is
 * a predefined set of codes, called the fixed codes.  The fixed method is
 * used if the block codes up smaller that way (usually for quite small
 * chunks), otherwise the dynamic method is used.  In the latter case, the
 * codes are customized to the probabilities in the current block, and so
 * can code it much better than the pre-determined fixed codes.
 *
 * The Huffman codes themselves are decoded using a multi-level table
 * lookup, in order to maximize the speed of decoding plus the speed of
 * building the decoding tables.  See the comments below that precede the
 * lbits and dbits tuning parameters.
 */

/*
 * Notes beyond the 1.93a appnote.txt:
 *
 *  1. Distance pointers never point before the beginning of the output
 *     stream.
 *  2. Distance pointers can point back across blocks, up to 32k away.
 *  3. There is an implied maximum of 7 bits for the bit length table and
 *     15 bits for the actual data.
 *  4. If only one code exists, then it is encoded using one bit.  (Zero
 *     would be more efficient, but perhaps a little confusing.)  If two
 *     codes exist, they are coded using one bit each (0 and 1).
 *  5. There is no way of sending zero distance codes--a dummy must be
 *     sent if there are none.  (History: a pre 2.0 version of PKZIP would
 *     store blocks with no distance codes, but this was discovered to be
 *     too harsh a criterion.)  Valid only for 1.93a.  2.04c does allow
 *     zero distance codes, which is sent as one code of zero bits in
 *     length.
 *  6. There are up to 286 literal/length codes.  Code 256 represents the
 *     end-of-block.  Note however that the static length tree defines
 *     288 codes just to fill out the Huffman codes.  Codes 286 and 287
 *     cannot be used though, since there is no length base or extra bits
 *     defined for them.  Similarly, there are up to 30 distance codes.
 *     However, static trees define 32 codes (all 5 bits) to fill out the
 *     Huffman codes, but the last two had better not show up in the data.
 *  7. Unzip can check dynamic Huffman blocks for complete code sets.
 *     The exception is that a single code would not be complete (see #4).
 *  8. The five bits following the block type is really the number of
 *     literal codes sent minus 257.
 *  9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
 *     (1+6+6).  Therefore, to output three times the length, you output
 *     three codes (1+1+1), whereas to output four times the same length,
 *     you only need two codes (1+3).  Hmm.
 * 10. In the tree reconstruction algorithm, Code = Code + Increment
 *     only if BitLength(i) is not zero.  (Pretty obvious.)
 * 11. Correction: 4 Bits: # of Bit Length codes - 4     (4 - 19)
 * 12. Note: length code 284 can represent 227-258, but length code 285
 *     really is 258.  The last length deserves its own, short code
 *     since it gets used a lot in very redundant files.  The length
 *     258 is special since 258 - 3 (the min match length) is 255.
 * 13. The literal/length and distance code bit lengths are read as a
 *     single stream of lengths.  It is possible (and advantageous) for
 *     a repeat code (16, 17, or 18) to go across the boundary between
 *     the two sets of lengths.
 */

#ifdef RCSID
static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #";
#endif

#ifndef __XEN__

#if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H)
#  include <sys/types.h>
#  include <stdlib.h>
#endif

#include "gzip.h"

#endif /* !__XEN__ */

/*
 * Huffman code lookup table entry--this entry is four bytes for machines
 * that have 16-bit pointers (e.g. PC's in the small or medium model).
 * Valid extra bits are 0..13.  e == 15 is EOB (end of block), e == 16
 * means that v is a literal, 16 < e < 32 means that v is a pointer to
 * the next table, which codes e - 16 bits, and lastly e == 99 indicates
 * an unused code.  If a code with e == 99 is looked up, this implies an
 * error in the data.
 */
struct huft {
    uch e;                /* number of extra bits or operation */
    uch b;                /* number of bits in this code or subcode */
    union {
        ush n;              /* literal, length base, or distance base */
        struct huft *t;     /* pointer to next level of table */
    } v;
};

/* Function prototypes */
static int huft_build(unsigned *, unsigned, unsigned,
                      const ush *, const ush *, struct huft **, int *);
static int huft_free(struct huft *);
static int inflate_codes(
    struct gunzip_state *s, struct huft *tl, struct huft *td, int bl, int bd);
static int inflate_stored(struct gunzip_state *s);
static int inflate_fixed(struct gunzip_state *s);
static int inflate_dynamic(struct gunzip_state *s);
static int inflate_block(struct gunzip_state *s, int *e);
static int inflate(struct gunzip_state *s);

/*
 * The inflate algorithm uses a sliding 32 K byte window on the uncompressed
 * stream to find repeated byte strings.  This is implemented here as a
 * circular buffer.  The index is updated simply by incrementing and then
 * ANDing with 0x7fff (32K-1).
 *
 * It is left to other modules to supply the 32 K area.  It is assumed
 * to be usable as if it were declared "uch slide[32768];" or as just
 * "uch *slide;" and then malloc'ed in the latter case.  The definition
 * must be in unzip.h, included above.
 */

/* Tables for deflate from PKZIP's appnote.txt. */
static const unsigned border[] = {    /* Order of the bit length code lengths */
    16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
static const ush cplens[] = {         /* Copy lengths for literal codes 257..285 */
    3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
    35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
/* note: see note #13 above about the 258 in this list. */
static const ush cplext[] = {         /* Extra bits for literal codes 257..285 */
    0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
    3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */
static const ush cpdist[] = {         /* Copy offsets for distance codes 0..29 */
    1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
    257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
    8193, 12289, 16385, 24577};
static const ush cpdext[] = {         /* Extra bits for distance codes */
    0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
    7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
    12, 12, 13, 13};

/*
 * Macros for inflate() bit peeking and grabbing.
 * The usage is:
 *
 *      NEEDBITS(j)
 *      x = b & mask_bits[j];
 *      DUMPBITS(j)
 *
 * where NEEDBITS makes sure that b has at least j bits in it, and
 * DUMPBITS removes the bits from b.  The macros use the variable k
 * for the number of bits in b.  Normally, b and k are register
 * variables for speed, and are initialized at the beginning of a
 * routine that uses these macros from a global bit buffer and count.
 *
 * If we assume that EOB will be the longest code, then we will never
 * ask for bits with NEEDBITS that are beyond the end of the stream.
 * So, NEEDBITS should not read any more bytes than are needed to
 * meet the request.  Then no bytes need to be "returned" to the buffer
 * at the end of the last block.
 *
 * However, this assumption is not true for fixed blocks--the EOB code
 * is 7 bits, but the other literal/length codes can be 8 or 9 bits.
 * (The EOB code is shorter than other codes because fixed blocks are
 * generally short.  So, while a block always has an EOB, many other
 * literal/length codes have a significantly lower probability of
 * showing up at all.)  However, by making the first table have a
 * lookup of seven bits, the EOB code will be found in that first
 * lookup, and so will not require that too many bits be pulled from
 * the stream.
 */

static const ush mask_bits[] = {
    0x0000,
    0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
    0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};

#define NEXTBYTE(s)  ({ int v = get_byte(s); if (v < 0) goto underrun; (uch)v; })
#define NEEDBITS(s, n) {while(k<(n)){b|=((ulg)NEXTBYTE(s))<<k;k+=8;}}
#define DUMPBITS(n) {b>>=(n);k-=(n);}

/*
 * Huffman code decoding is performed using a multi-level table lookup.
 * The fastest way to decode is to simply build a lookup table whose
 * size is determined by the longest code.  However, the time it takes
 * to build this table can also be a factor if the data being decoded
 * is not very long.  The most common codes are necessarily the
 * shortest codes, so those codes dominate the decoding time, and hence
 * the speed.  The idea is you can have a shorter table that decodes the
 * shorter, more probable codes, and then point to subsidiary tables for
 * the longer codes.  The time it costs to decode the longer codes is
 * then traded against the time it takes to make longer tables.
 *
 * This results of this trade are in the variables lbits and dbits
 * below.  lbits is the number of bits the first level table for literal/
 * length codes can decode in one step, and dbits is the same thing for
 * the distance codes.  Subsequent tables are also less than or equal to
 * those sizes.  These values may be adjusted either when all of the
 * codes are shorter than that, in which case the longest code length in
 * bits is used, or when the shortest code is *longer* than the requested
 * table size, in which case the length of the shortest code in bits is
 * used.
 *
 * There are two different values for the two tables, since they code a
 * different number of possibilities each.  The literal/length table
 * codes 286 possible values, or in a flat code, a little over eight
 * bits.  The distance table codes 30 possible values, or a little less
 * than five bits, flat.  The optimum values for speed end up being
 * about one bit more than those, so lbits is 8+1 and dbits is 5+1.
 * The optimum values may differ though from machine to machine, and
 * possibly even between compilers.  Your mileage may vary.
 */

static const int lbits = 9;          /* bits in base literal/length lookup table */
static const int dbits = 6;          /* bits in base distance lookup table */

/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
#define BMAX 16         /* maximum bit length of any code (16 for explode) */
#define N_MAX 288       /* maximum number of codes in any set */

/*
 * Given a list of code lengths and a maximum table size, make a set of
 * tables to decode that set of codes.  Return zero on success, one if
 * the given code set is incomplete (the tables are still built in this
 * case), two if the input is invalid (all zero length codes or an
 * oversubscribed set of lengths), and three if not enough memory.
 *
 * @param b Code lengths in bits (all assumed <= BMAX)
 * @param n Number of codes (assumed <= N_MAX)
 * @param s Number of simple-valued codes (0..s-1)
 * @param d List of base values for non-simple codes
 * @param e List of extra bits for non-simple codes
 * @param t Result: starting table
 * @param m Maximum lookup bits, returns actual
 */
static int __init huft_build(
    unsigned *b, unsigned n, unsigned s, const ush *d, const ush *e,
    struct huft **t, int *m)
{
    unsigned a;                   /* counter for codes of length k */
    unsigned f;                   /* i repeats in table every f entries */
    int g;                        /* maximum code length */
    int h;                        /* table level */
    register unsigned i;          /* counter, current code */
    register unsigned j;          /* counter */
    register int k;               /* number of bits in current code */
    int l;                        /* bits per table (returned in m) */
    register unsigned *p;         /* pointer into c[], b[], or v[] */
    register struct huft *q;      /* points to current table */
    struct huft r;                /* table entry for structure assignment */
    register int w;               /* bits before this table == (l * h) */
    unsigned *xp;                 /* pointer into x */
    int y;                        /* number of dummy codes added */
    unsigned z;                   /* number of entries in current table */
    struct {
        unsigned c[BMAX+1];           /* bit length count table */
        struct huft *u[BMAX];         /* table stack */
        unsigned v[N_MAX];            /* values in order of bit length */
        unsigned x[BMAX+1];           /* bit offsets, then code stack */
    } *stk;
    unsigned *c, *v, *x;
    struct huft **u;
    int ret;

    DEBG("huft1 ");

    stk = malloc(sizeof(*stk));
    if (stk == NULL)
        return 3;   /* out of memory */

    c = stk->c;
    v = stk->v;
    x = stk->x;
    u = stk->u;

    /* Generate counts for each bit length */
    memzero(stk->c, sizeof(stk->c));
    p = b;  i = n;
    do {
        Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"),
                     n-i, *p));
        c[*p]++;                    /* assume all entries <= BMAX */
        p++;                      /* Can't combine with above line (Solaris bug) */
    } while (--i);
    if (c[0] == n)                /* null input--all zero length codes */
    {
        *t = (struct huft *)NULL;
        *m = 0;
        ret = 2;
        goto out;
    }

    DEBG("huft2 ");

    /* Find minimum and maximum length, bound *m by those */
    l = *m;
    for (j = 1; j <= BMAX; j++)
        if (c[j])
            break;
    k = j;                        /* minimum code length */
    if ((unsigned)l < j)
        l = j;
    for (i = BMAX; i; i--)
        if (c[i])
            break;
    g = i;                        /* maximum code length */
    if ((unsigned)l > i)
        l = i;
    *m = l;

    DEBG("huft3 ");

    /* Adjust last length count to fill out codes, if needed */
    for (y = 1 << j; j < i; j++, y <<= 1)
        if ((y -= c[j]) < 0) {
            ret = 2;                 /* bad input: more codes than bits */
            goto out;
        }
    if ((y -= c[i]) < 0) {
        ret = 2;
        goto out;
    }
    c[i] += y;

    DEBG("huft4 ");

    /* Generate starting offsets into the value table for each length */
    x[1] = j = 0;
    p = c + 1;  xp = x + 2;
    while (--i) {                 /* note that i == g from above */
        *xp++ = (j += *p++);
    }

    DEBG("huft5 ");

    /* Make a table of values in order of bit lengths */
    p = b;  i = 0;
    do {
        if ((j = *p++) != 0)
            v[x[j]++] = i;
    } while (++i < n);
    n = x[g];                   /* set n to length of v */

    DEBG("h6 ");

    /* Generate the Huffman codes and for each, make the table entries */
    x[0] = i = 0;                 /* first Huffman code is zero */
    p = v;                        /* grab values in bit order */
    h = -1;                       /* no tables yet--level -1 */
    w = -l;                       /* bits decoded == (l * h) */
    u[0] = (struct huft *)NULL;   /* just to keep compilers happy */
    q = (struct huft *)NULL;      /* ditto */
    z = 0;                        /* ditto */
    DEBG("h6a ");

    /* go through the bit lengths (k already is bits in shortest code) */
    for (; k <= g; k++)
    {
        DEBG("h6b ");
        a = c[k];
        while (a--)
        {
            DEBG("h6b1 ");
            /* here i is the Huffman code of length k bits for value *p */
            /* make tables up to required level */
            while (k > w + l)
            {
                DEBG1("1 ");
                h++;
                w += l;                 /* previous table always l bits */

                /* compute minimum size table less than or equal to l bits */
                z = (z = g - w) > (unsigned)l ? l : z;  /* upper limit on table size */
                if ((f = 1 << (j = k - w)) > a + 1)     /* try a k-w bit table */
                {                       /* too few codes for k-w bit table */
                    DEBG1("2 ");
                    f -= a + 1;           /* deduct codes from patterns left */
                    xp = c + k;
                    if (j < z)
                        while (++j < z)       /* try smaller tables up to z bits */
                        {
                            if ((f <<= 1) <= *++xp)
                                break;            /* enough codes to use up j bits */
                            f -= *xp;           /* else deduct codes from patterns */
                        }
                }
                DEBG1("3 ");
                z = 1 << j;             /* table entries for j-bit table */

                /* allocate and link in new table */
                if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) ==
                    (struct huft *)NULL)
                {
                    if (h)
                        huft_free(u[0]);
                    ret = 3;             /* not enough memory */
                    goto out;
                }
                DEBG1("4 ");
                *t = q + 1;             /* link to list for huft_free() */
                *(t = &(q->v.t)) = (struct huft *)NULL;
                u[h] = ++q;             /* table starts after link */

                DEBG1("5 ");
                /* connect to last table, if there is one */
                if (h)
                {
                    x[h] = i;             /* save pattern for backing up */
                    r.b = (uch)l;         /* bits to dump before this table */
                    r.e = (uch)(16 + j);  /* bits in this table */
                    r.v.t = q;            /* pointer to this table */
                    j = i >> (w - l);     /* (get around Turbo C bug) */
                    u[h-1][j] = r;        /* connect to last table */
                }
                DEBG1("6 ");
            }
            DEBG("h6c ");

            /* set up table entry in r */
            r.b = (uch)(k - w);
            if (p >= v + n)
                r.e = 99;               /* out of values--invalid code */
            else if (*p < s)
            {
                r.e = (uch)(*p < 256 ? 16 : 15);    /* 256 is end-of-block code */
                r.v.n = (ush)(*p);             /* simple code is just the value */
                p++;                           /* one compiler does not like *p++ */
            }
            else
            {
                r.e = (uch)e[*p - s];   /* non-simple--look up in lists */
                r.v.n = d[*p++ - s];
            }
            DEBG("h6d ");

            /* fill code-like entries with r */
            f = 1 << (k - w);
            for (j = i >> w; j < z; j += f)
                q[j] = r;

            /* backwards increment the k-bit code i */
            for (j = 1 << (k - 1); i & j; j >>= 1)
                i ^= j;
            i ^= j;

            /* backup over finished tables */
            while ((i & ((1 << w) - 1)) != x[h])
            {
                h--;                    /* don't need to update q */
                w -= l;
            }
            DEBG("h6e ");
        }
        DEBG("h6f ");
    }

    DEBG("huft7 ");

    /* Return true (1) if we were given an incomplete table */
    ret = y != 0 && g != 1;

 out:
    free(stk);
    return ret;
}

/*
 * Free the malloc'ed tables built by huft_build(), which makes a linked
 * list of the tables it made, with the links in a dummy first entry of
 * each table.
 *
 * @param t Table to free
 */
static int __init huft_free(struct huft *t)
{
    register struct huft *p, *q;

    /* Go through linked list, freeing from the malloced (t[-1]) address. */
    p = t;
    while (p != (struct huft *)NULL)
    {
        q = (--p)->v.t;
        free((char*)p);
        p = q;
    }
    return 0;
}

/*
 * inflate (decompress) the codes in a deflated (compressed) block.
 * Return an error code or zero if it all goes ok.
 *
 * @param huft tl Literal/length decoder tables
 * @param huft td Distance decoder tables
 * @param bl  Number of bits decoded by tl[]
 * @param bd  Number of bits decoded by td[]
 */
static int __init inflate_codes(
    struct gunzip_state *s, struct huft *tl, struct huft *td, int bl, int bd)
{
    register unsigned e;  /* table entry flag/number of extra bits */
    unsigned n, d;        /* length and index for copy */
    unsigned w;           /* current window position */
    struct huft *t;       /* pointer to table entry */
    unsigned ml, md;      /* masks for bl and bd bits */
    register ulg b;       /* bit buffer */
    register unsigned k;  /* number of bits in bit buffer */


    /* make local copies of globals */
    b = s->bb;                    /* initialize bit buffer */
    k = s->bk;
    w = s->wp;                    /* initialize window position */

    /* inflate the coded data */
    ml = mask_bits[bl];           /* precompute masks for speed */
    md = mask_bits[bd];
    for (;;)                      /* do until end of block */
    {
        NEEDBITS(s, (unsigned)bl);
        if ((e = (t = tl + ((unsigned)b & ml))->e) > 16)
            do {
                if (e == 99)
                    return 1;
                DUMPBITS(t->b);
                e -= 16;
                NEEDBITS(s, e);
            } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16);
        DUMPBITS(t->b);
        if (e == 16)                /* then it's a literal */
        {
            s->window[w++] = (uch)t->v.n;
            Tracevv((stderr, "%c", s->window[w-1]));
            if (w == WSIZE)
            {
                s->wp = w;
                flush_window(s);
                w = 0;
            }
        }
        else                        /* it's an EOB or a length */
        {
            /* exit if end of block */
            if (e == 15)
                break;

            /* get length of block to copy */
            NEEDBITS(s, e);
            n = t->v.n + ((unsigned)b & mask_bits[e]);
            DUMPBITS(e);

            /* decode distance of block to copy */
            NEEDBITS(s, (unsigned)bd);
            if ((e = (t = td + ((unsigned)b & md))->e) > 16)
                do {
                    if (e == 99)
                        return 1;
                    DUMPBITS(t->b);
                    e -= 16;
                    NEEDBITS(s, e);
                } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16);
            DUMPBITS(t->b);
            NEEDBITS(s, e);
            d = w - t->v.n - ((unsigned)b & mask_bits[e]);
            DUMPBITS(e);
            Tracevv((stderr,"\\[%d,%d]", w-d, n));

            /* do the copy */
            do {
                n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e);
                if (w - d >= e)         /* (this test assumes unsigned comparison) */
                {
                    memcpy(s->window + w, s->window + d, e);
                    w += e;
                    d += e;
                }
                else                      /* do it slow to avoid memcpy() overlap */
                    do {
                        s->window[w++] = s->window[d++];
                        Tracevv((stderr, "%c", s->window[w-1]));
                    } while (--e);
                if (w == WSIZE)
                {
                    s->wp = w;
                    flush_window(s);
                    w = 0;
                }
            } while (n);
        }
    }

    /* restore the globals from the locals */
    s->wp = w;                    /* restore global window position */
    s->bb = b;                    /* restore global bit buffer */
    s->bk = k;

    /* done */
    return 0;

 underrun:
    return 4;   /* Input underrun */
}

/* "decompress" an inflated type 0 (stored) block. */
static int __init inflate_stored(struct gunzip_state *s)
{
    unsigned n;           /* number of bytes in block */
    unsigned w;           /* current window position */
    register ulg b;       /* bit buffer */
    register unsigned k;  /* number of bits in bit buffer */

    DEBG("<stor");

    /* make local copies of globals */
    b = s->bb;                    /* initialize bit buffer */
    k = s->bk;
    w = s->wp;                    /* initialize window position */


    /* go to byte boundary */
    n = k & 7;
    DUMPBITS(n);


    /* get the length and its complement */
    NEEDBITS(s, 16);
    n = ((unsigned)b & 0xffff);
    DUMPBITS(16);
    NEEDBITS(s, 16);
    if (n != (unsigned)((~b) & 0xffff))
        return 1;                   /* error in compressed data */
    DUMPBITS(16);

    /* read and output the compressed data */
    while (n--)
    {
        NEEDBITS(s, 8);
        s->window[w++] = (uch)b;
        if (w == WSIZE)
        {
            s->wp = w;
            flush_window(s);
            w = 0;
        }
        DUMPBITS(8);
    }

    /* restore the globals from the locals */
    s->wp = w;                    /* restore global window position */
    s->bb = b;                    /* restore global bit buffer */
    s->bk = k;

    DEBG(">");
    return 0;

 underrun:
    return 4;   /* Input underrun */
}


/*
 * We use `noinline' here to prevent gcc-3.5 from using too much stack space
 */

/*
 * decompress an inflated type 1 (fixed Huffman codes) block.  We should
 * either replace this with a custom decoder, or at least precompute the
 * Huffman tables.
 */
static int noinline __init inflate_fixed(struct gunzip_state *s)
{
    int i;                /* temporary variable */
    struct huft *tl;      /* literal/length code table */
    struct huft *td;      /* distance code table */
    int bl;               /* lookup bits for tl */
    int bd;               /* lookup bits for td */
    unsigned *l;          /* length list for huft_build */

    DEBG("<fix");

    l = malloc(sizeof(*l) * 288);
    if (l == NULL)
        return 3;   /* out of memory */

    /* set up literal table */
    for (i = 0; i < 144; i++)
        l[i] = 8;
    for (; i < 256; i++)
        l[i] = 9;
    for (; i < 280; i++)
        l[i] = 7;
    for (; i < 288; i++)          /* make a complete, but wrong code set */
        l[i] = 8;
    bl = 7;
    if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
        free(l);
        return i;
    }

    /* set up distance table */
    for (i = 0; i < 30; i++)      /* make an incomplete code set */
        l[i] = 5;
    bd = 5;
    if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1)
    {
        huft_free(tl);
        free(l);

        DEBG(">");
        return i;
    }

    /* decompress until an end-of-block code */
    i = inflate_codes(s, tl, td, bl, bd);

    /* free the decoding tables, return */
    free(l);
    huft_free(tl);
    huft_free(td);

    return !!i;
}

/*
 * We use `noinline' here to prevent gcc-3.5 from using too much stack space
 */

/* decompress an inflated type 2 (dynamic Huffman codes) block. */
static int noinline __init inflate_dynamic(struct gunzip_state *s)
{
    int i;                /* temporary variables */
    unsigned j;
    unsigned l;           /* last length */
    unsigned m;           /* mask for bit lengths table */
    unsigned n;           /* number of lengths to get */
    struct huft *tl;      /* literal/length code table */
    struct huft *td;      /* distance code table */
    int bl;               /* lookup bits for tl */
    int bd;               /* lookup bits for td */
    unsigned nb;          /* number of bit length codes */
    unsigned nl;          /* number of literal/length codes */
    unsigned nd;          /* number of distance codes */
    unsigned *ll;         /* literal/length and distance code lengths */
    register ulg b;       /* bit buffer */
    register unsigned k;  /* number of bits in bit buffer */
    int ret;

    DEBG("<dyn");

    ll = malloc(sizeof(*ll) * (286+30));  /* literal/length and distance code lengths */

    if (ll == NULL)
        return 1;

    /* make local bit buffer */
    b = s->bb;
    k = s->bk;

    /* read in table lengths */
    NEEDBITS(s, 5);
    nl = 257 + ((unsigned)b & 0x1f);      /* number of literal/length codes */
    DUMPBITS(5);
    NEEDBITS(s, 5);
    nd = 1 + ((unsigned)b & 0x1f);        /* number of distance codes */
    DUMPBITS(5);
    NEEDBITS(s, 4);
    nb = 4 + ((unsigned)b & 0xf);         /* number of bit length codes */
    DUMPBITS(4);
    if (nl > 286 || nd > 30)
    {
        ret = 1;             /* bad lengths */
        goto out;
    }

    DEBG("dyn1 ");

    /* read in bit-length-code lengths */
    for (j = 0; j < nb; j++)
    {
        NEEDBITS(s, 3);
        ll[border[j]] = (unsigned)b & 7;
        DUMPBITS(3);
    }
    for (; j < 19; j++)
        ll[border[j]] = 0;

    DEBG("dyn2 ");

    /* build decoding table for trees--single level, 7 bit lookup */
    bl = 7;
    if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0)
    {
        if (i == 1)
            huft_free(tl);
        ret = i;                   /* incomplete code set */
        goto out;
    }

    DEBG("dyn3 ");

    /* read in literal and distance code lengths */
    n = nl + nd;
    m = mask_bits[bl];
    i = l = 0;
    while ((unsigned)i < n)
    {
        NEEDBITS(s, (unsigned)bl);
        j = (td = tl + ((unsigned)b & m))->b;
        DUMPBITS(j);
        j = td->v.n;
        if (j < 16)                 /* length of code in bits (0..15) */
            ll[i++] = l = j;          /* save last length in l */
        else if (j == 16)           /* repeat last length 3 to 6 times */
        {
            NEEDBITS(s, 2);
            j = 3 + ((unsigned)b & 3);
            DUMPBITS(2);
            if ((unsigned)i + j > n) {
                ret = 1;
                goto out;
            }
            while (j--)
                ll[i++] = l;
        }
        else if (j == 17)           /* 3 to 10 zero length codes */
        {
            NEEDBITS(s, 3);
            j = 3 + ((unsigned)b & 7);
            DUMPBITS(3);
            if ((unsigned)i + j > n) {
                ret = 1;
                goto out;
            }
            while (j--)
                ll[i++] = 0;
            l = 0;
        }
        else                        /* j == 18: 11 to 138 zero length codes */
        {
            NEEDBITS(s, 7);
            j = 11 + ((unsigned)b & 0x7f);
            DUMPBITS(7);
            if ((unsigned)i + j > n) {
                ret = 1;
                goto out;
            }
            while (j--)
                ll[i++] = 0;
            l = 0;
        }
    }

    DEBG("dyn4 ");

    /* free decoding table for trees */
    huft_free(tl);

    DEBG("dyn5 ");

    /* restore the global bit buffer */
    s->bb = b;
    s->bk = k;

    DEBG("dyn5a ");

    /* build the decoding tables for literal/length and distance codes */
    bl = lbits;
    if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0)
    {
        DEBG("dyn5b ");
        if (i == 1) {
            error("incomplete literal tree");
            huft_free(tl);
        }
        ret = i;                   /* incomplete code set */
        goto out;
    }
    DEBG("dyn5c ");
    bd = dbits;
    if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0)
    {
        DEBG("dyn5d ");
        if (i == 1) {
            error("incomplete distance tree");
            huft_free(td);
        }
        huft_free(tl);
        ret = i;                   /* incomplete code set */
        goto out;
    }

    DEBG("dyn6 ");

    /* decompress until an end-of-block code */
    ret = !!inflate_codes(s, tl, td, bl, bd);

    if ( !ret )
       DEBG("dyn7 ");

    /* free the decoding tables, return */
    huft_free(tl);
    huft_free(td);

    if ( !ret )
       DEBG(">");
 out:
    free(ll);
    return ret;

 underrun:
    ret = 4;   /* Input underrun */
    goto out;
}

/*
 * decompress an inflated block
 *
 * @param e Last block flag
 */
static int __init inflate_block(struct gunzip_state *s, int *e)
{
    unsigned t;           /* block type */
    register ulg b;       /* bit buffer */
    register unsigned k;  /* number of bits in bit buffer */

    DEBG("<blk");

    /* make local bit buffer */
    b = s->bb;
    k = s->bk;

    /* read in last block bit */
    NEEDBITS(s, 1);
    *e = (int)b & 1;
    DUMPBITS(1);

    /* read in block type */
    NEEDBITS(s, 2);
    t = (unsigned)b & 3;
    DUMPBITS(2);

    /* restore the global bit buffer */
    s->bb = b;
    s->bk = k;

    /* inflate that block type */
    if (t == 2)
        return inflate_dynamic(s);
    if (t == 0)
        return inflate_stored(s);
    if (t == 1)
        return inflate_fixed(s);

    DEBG(">");

    /* bad block type */
    return 2;

 underrun:
    return 4;   /* Input underrun */
}

/* decompress an inflated entry */
static int __init inflate(struct gunzip_state *s)
{
    int e;                /* last block flag */
    int r;                /* result code */

    /* initialize window, bit buffer */
    s->wp = 0;
    s->bk = 0;
    s->bb = 0;

    /* decompress until the last block */
    do {
        r = inflate_block(s, &e);
        if (r)
            return r;
    } while (!e);

    /* Undo too much lookahead. The next read will be byte aligned so we
     * can discard unused bits in the last meaningful byte.
     */
    while ( s->bk >= 8 )
    {
        s->bk -= 8;
        s->inptr--;
    }

    flush_window(s);

    /* return success */
    return 0;
}

/**********************************************************************
 *
 * The following are support routines for inflate.c
 *
 **********************************************************************/

/*
 * Code to compute the CRC-32 table. Borrowed from
 * gzip-1.0.3/makecrc.c.
 */

static void __init makecrc(struct gunzip_state *s)
{
/* Not copyrighted 1990 Mark Adler */

    unsigned long c;      /* crc shift register */
    unsigned long e;      /* polynomial exclusive-or pattern */
    int i;                /* counter for all possible eight bit values */
    int k;                /* byte being shifted into crc apparatus */

    /* terms of polynomial defining this crc (except x^32): */
    static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};

    /* Make exclusive-or pattern from polynomial */
    e = 0;
    for (i = 0; i < sizeof(p)/sizeof(int); i++)
        e |= 1L << (31 - p[i]);

    s->crc_32_tab[0] = 0;

    for (i = 1; i < 256; i++)
    {
        c = 0;
        for (k = i | 256; k != 1; k >>= 1)
        {
            c = c & 1 ? (c >> 1) ^ e : c >> 1;
            if (k & 1)
                c ^= e;
        }
        s->crc_32_tab[i] = c;
    }

    s->crc = 0;
}

/* gzip flag byte */
#define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
#define COMMENT      0x10 /* bit 4 set: file comment present */
#define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
#define RESERVED     0xC0 /* bit 6,7:   reserved */

/*
 * Do the uncompression!
 */
static int __init gunzip(struct gunzip_state *s)
{
    uch flags;
    unsigned char magic[2]; /* magic header */
    char method;
    ulg orig_crc = 0;       /* original crc */
    ulg orig_len = 0;       /* original uncompressed length */
    int res;

    magic[0] = NEXTBYTE(s);
    magic[1] = NEXTBYTE(s);
    method   = NEXTBYTE(s);

    if (magic[0] != 037 ||                            /* octal-ok */
        ((magic[1] != 0213) && (magic[1] != 0236))) { /* octal-ok */
        error("bad gzip magic numbers");
        return -1;
    }

    /* We only support method #8, DEFLATED */
    if (method != 8)  {
        error("internal error, invalid method");
        return -1;
    }

    flags  = (uch)get_byte(s);
    if ((flags & ENCRYPTED) != 0) {
        error("Input is encrypted");
        return -1;
    }
    if ((flags & CONTINUATION) != 0) {
        error("Multi part input");
        return -1;
    }
    if ((flags & RESERVED) != 0) {
        error("Input has invalid flags");
        return -1;
    }
    NEXTBYTE(s); /* Get timestamp */
    NEXTBYTE(s);
    NEXTBYTE(s);
    NEXTBYTE(s);

    NEXTBYTE(s); /* Ignore extra flags for the moment */
    NEXTBYTE(s); /* Ignore OS type for the moment */

    if ((flags & EXTRA_FIELD) != 0) {
        unsigned int len = NEXTBYTE(s);

        len |= (unsigned int)NEXTBYTE(s) << 8;

        while ( len-- )
            NEXTBYTE(s);
    }

    /* Get original file name if it was truncated */
    if ((flags & ORIG_NAME) != 0) {
        /* Discard the old name */
        while ( NEXTBYTE(s) != 0) /* null */
            ;
    }

    /* Discard file comment if any */
    if ((flags & COMMENT) != 0) {
        while ( NEXTBYTE(s) != 0 ) /* null */
            ;
    }

    /* Decompress */
    if ( (res = inflate(s)) )
    {
        switch (res) {
        case 0:
            break;
        case 1:
            error("invalid compressed format (err=1)");
            break;
        case 2:
            error("invalid compressed format (err=2)");
            break;
        case 3:
            error("out of memory");
            break;
        case 4:
            error("out of input data");
            break;
        default:
            error("invalid compressed format (other)");
        }
        return -1;
    }

    /* Get the crc and original length */
    /* crc32  (see algorithm.doc)
     * uncompressed input size modulo 2^32
     */
    orig_crc  = (ulg) NEXTBYTE(s);
    orig_crc |= (ulg) NEXTBYTE(s) << 8;
    orig_crc |= (ulg) NEXTBYTE(s) << 16;
    orig_crc |= (ulg) NEXTBYTE(s) << 24;

    orig_len  = (ulg) NEXTBYTE(s);
    orig_len |= (ulg) NEXTBYTE(s) << 8;
    orig_len |= (ulg) NEXTBYTE(s) << 16;
    orig_len |= (ulg) NEXTBYTE(s) << 24;

    /* Validate decompression */
    if ( orig_crc != s->crc )
    {
        error("crc error");
        return -1;
    }

    if ( orig_len != s->bytes_out )
    {
        error("length error");
        return -1;
    }
    return 0;

 underrun:   /* NEXTBYTE() goto's here if needed */
    error("out of input data");
    return -1;
}

/*
 * Local variables:
 * mode: C
 * c-file-style: "BSD"
 * c-basic-offset: 4
 * indent-tabs-mode: nil
 * End:
 */
