GCOV - Varnish Cache


/* inflate.c -- zlib decompression
 * Copyright (C) 1995-2022 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/*
 * Change history:
 *
 * 1.2.beta0    24 Nov 2002
 * - First version -- complete rewrite of inflate to simplify code, avoid
 *   creation of window when not needed, minimize use of window when it is
 *   needed, make inffast.c even faster, implement gzip decoding, and to
 *   improve code readability and style over the previous zlib inflate code
 *
 * 1.2.beta1    25 Nov 2002
 * - Use pointers for available input and output checking in inffast.c
 * - Remove input and output counters in inffast.c
 * - Change inffast.c entry and loop from avail_in >= 7 to >= 6
 * - Remove unnecessary second byte pull from length extra in inffast.c
 * - Unroll direct copy to three copies per loop in inffast.c
 *
 * 1.2.beta2    4 Dec 2002
 * - Change external routine names to reduce potential conflicts
 * - Correct filename to inffixed.h for fixed tables in inflate.c
 * - Make hbuf[] unsigned char to match parameter type in inflate.c
 * - Change strm->next_out[-state->offset] to *(strm->next_out - state->offset)
 *   to avoid negation problem on Alphas (64 bit) in inflate.c
 *
 * 1.2.beta3    22 Dec 2002
 * - Add comments on state->bits assertion in inffast.c
 * - Add comments on op field in inftrees.h
 * - Fix bug in reuse of allocated window after inflateReset()
 * - Remove bit fields--back to byte structure for speed
 * - Remove distance extra == 0 check in inflate_fast()--only helps for lengths
 * - Change post-increments to pre-increments in inflate_fast(), PPC biased?
 * - Add compile time option, POSTINC, to use post-increments instead (Intel?)
 * - Make MATCH copy in inflate() much faster for when inflate_fast() not used
 * - Use local copies of stream next and avail values, as well as local bit
 *   buffer and bit count in inflate()--for speed when inflate_fast() not used
 *
 * 1.2.beta4    1 Jan 2003
 * - Split ptr - 257 statements in inflate_table() to avoid compiler warnings
 * - Move a comment on output buffer sizes from inffast.c to inflate.c
 * - Add comments in inffast.c to introduce the inflate_fast() routine
 * - Rearrange window copies in inflate_fast() for speed and simplification
 * - Unroll last copy for window match in inflate_fast()
 * - Use local copies of window variables in inflate_fast() for speed
 * - Pull out common wnext == 0 case for speed in inflate_fast()
 * - Make op and len in inflate_fast() unsigned for consistency
 * - Add FAR to lcode and dcode declarations in inflate_fast()
 * - Simplified bad distance check in inflate_fast()
 * - Added inflateBackInit(), inflateBack(), and inflateBackEnd() in new
 *   source file infback.c to provide a call-back interface to inflate for
 *   programs like gzip and unzip -- uses window as output buffer to avoid
 *   window copying
 *
 * 1.2.beta5    1 Jan 2003
 * - Improved inflateBack() interface to allow the caller to provide initial
 *   input in strm.
 * - Fixed stored blocks bug in inflateBack()
 *
 * 1.2.beta6    4 Jan 2003
 * - Added comments in inffast.c on effectiveness of POSTINC
 * - Typecasting all around to reduce compiler warnings
 * - Changed loops from while (1) or do {} while (1) to for (;;), again to
 *   make compilers happy
 * - Changed type of window in inflateBackInit() to unsigned char *
 *
 * 1.2.beta7    27 Jan 2003
 * - Changed many types to unsigned or unsigned short to avoid warnings
 * - Added inflateCopy() function
 *
 * 1.2.0        9 Mar 2003
 * - Changed inflateBack() interface to provide separate opaque descriptors
 *   for the in() and out() functions
 * - Changed inflateBack() argument and in_func typedef to swap the length
 *   and buffer address return values for the input function
 * - Check next_in and next_out for Z_NULL on entry to inflate()
 *
 * The history for versions after 1.2.0 are in ChangeLog in zlib distribution.
 */

#include "zutil.h"
#include "inftrees.h"
#include "inflate.h"
#include "inffast.h"

#ifdef MAKEFIXED
#  ifndef BUILDFIXED
#    define BUILDFIXED
#  endif
#endif

local int inflateStateCheck(z_streamp strm) {
    struct inflate_state FAR *state;
    if (strm == Z_NULL ||
        strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
        return 1;
    state = (struct inflate_state FAR *)strm->state;
    if (state == Z_NULL || state->strm != strm ||
        state->mode < HEAD || state->mode > SYNC)
        return 1;
    return 0;
}

int ZEXPORT inflateResetKeep(z_streamp strm) {
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    strm->total_in = strm->total_out = state->total = 0;
    strm->start_bit = strm->stop_bit = strm->last_bit = 0;
    strm->msg = Z_NULL;
    if (state->wrap)        /* to support ill-conceived Java test suite */
        strm->adler = state->wrap & 1;
    state->mode = HEAD;
    state->last = 0;
    state->havedict = 0;
    state->flags = -1;
    state->dmax = 32768U;
    state->head = Z_NULL;
    state->hold = 0;
    state->bits = 0;
    state->lencode = state->distcode = state->next = state->codes;
    state->sane = 1;
    state->back = -1;
    Tracev((stderr, "inflate: reset\n"));
    return Z_OK;
}

int ZEXPORT inflateReset(z_streamp strm) {
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    state->wsize = 0;
    state->whave = 0;
    state->wnext = 0;
    return inflateResetKeep(strm);
}

int ZEXPORT inflateReset2(z_streamp strm, int windowBits) {
    int wrap;
    struct inflate_state FAR *state;

    /* get the state */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;

    /* extract wrap request from windowBits parameter */
    if (windowBits < 0) {
        if (windowBits < -15)
            return Z_STREAM_ERROR;
        wrap = 0;
        windowBits = -windowBits;
    }
    else {
        wrap = (windowBits >> 4) + 5;
#ifdef GUNZIP
        if (windowBits < 48)
            windowBits &= 15;
#endif
    }

    /* set number of window bits, free window if different */
    if (windowBits && (windowBits < 8 || windowBits > 15))
        return Z_STREAM_ERROR;
    if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
        ZFREE(strm, state->window);
        state->window = Z_NULL;
    }

    /* update state and reset the rest of it */
    state->wrap = wrap;
    state->wbits = (unsigned)windowBits;
    return inflateReset(strm);
}

int ZEXPORT inflateInit2_(z_streamp strm, int windowBits,
                          const char *version, int stream_size) {
    int ret;
    struct inflate_state FAR *state;

    if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
        stream_size != (int)(sizeof(z_stream)))
        return Z_VERSION_ERROR;
    if (strm == Z_NULL) return Z_STREAM_ERROR;
    strm->msg = Z_NULL;                 /* in case we return an error */
    if (strm->zalloc == (alloc_func)0) {
#ifdef Z_SOLO
        return Z_STREAM_ERROR;
#else
        strm->zalloc = zcalloc;
        strm->opaque = (voidpf)0;
#endif
    }
    if (strm->zfree == (free_func)0)
#ifdef Z_SOLO
        return Z_STREAM_ERROR;
#else
        strm->zfree = zcfree;
#endif
    state = (struct inflate_state FAR *)
            ZALLOC(strm, 1, sizeof(struct inflate_state));
    if (state == Z_NULL) return Z_MEM_ERROR;
    Tracev((stderr, "inflate: allocated\n"));
    strm->state = (struct internal_state FAR *)state;
    state->strm = strm;
    state->window = Z_NULL;
    state->mode = HEAD;     /* to pass state test in inflateReset2() */
    ret = inflateReset2(strm, windowBits);
    if (ret != Z_OK) {
        ZFREE(strm, state);
        strm->state = Z_NULL;
    }
    return ret;
}

#ifdef NOVGZ

int ZEXPORT inflateInit_(z_streamp strm, const char *version,
                         int stream_size) {
    return inflateInit2_(strm, DEF_WBITS, version, stream_size);
}

int ZEXPORT inflatePrime(z_streamp strm, int bits, int value) {
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    if (bits == 0)
        return Z_OK;
    state = (struct inflate_state FAR *)strm->state;
    if (bits < 0) {
        state->hold = 0;
        state->bits = 0;
        return Z_OK;
    }
    if (bits > 16 || state->bits + (uInt)bits > 32) return Z_STREAM_ERROR;
    value &= (1L << bits) - 1;
    state->hold += (unsigned)value << state->bits;
    state->bits += (uInt)bits;
    return Z_OK;
}

#endif /* NOVGZ */

/*
   Return state with length and distance decoding tables and index sizes set to
   fixed code decoding.  Normally this returns fixed tables from inffixed.h.
   If BUILDFIXED is defined, then instead this routine builds the tables the
   first time it's called, and returns those tables the first time and
   thereafter.  This reduces the size of the code by about 2K bytes, in
   exchange for a little execution time.  However, BUILDFIXED should not be
   used for threaded applications, since the rewriting of the tables and virgin
   may not be thread-safe.
 */
local void fixedtables(struct inflate_state FAR *state) {
#ifdef BUILDFIXED
    static int virgin = 1;
    static code *lenfix, *distfix;
    static code fixed[544];

    /* build fixed huffman tables if first call (may not be thread safe) */
    if (virgin) {
        unsigned sym, bits;
        static code *next;

        /* literal/length table */
        sym = 0;
        while (sym < 144) state->lens[sym++] = 8;
        while (sym < 256) state->lens[sym++] = 9;
        while (sym < 280) state->lens[sym++] = 7;
        while (sym < 288) state->lens[sym++] = 8;
        next = fixed;
        lenfix = next;
        bits = 9;
        inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);

        /* distance table */
        sym = 0;
        while (sym < 32) state->lens[sym++] = 5;
        distfix = next;
        bits = 5;
        inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);

        /* do this just once */
        virgin = 0;
    }
#else /* !BUILDFIXED */
#   include "inffixed.h"
#endif /* BUILDFIXED */
    state->lencode = lenfix;
    state->lenbits = 9;
    state->distcode = distfix;
    state->distbits = 5;
}

#ifdef MAKEFIXED
#include <stdio.h>

/*
   Write out the inffixed.h that is #include'd above.  Defining MAKEFIXED also
   defines BUILDFIXED, so the tables are built on the fly.  makefixed() writes
   those tables to stdout, which would be piped to inffixed.h.  A small program
   can simply call makefixed to do this:

    void makefixed(void);

    int main(void)
    {
        makefixed();
        return 0;
    }

   Then that can be linked with zlib built with MAKEFIXED defined and run:

    a.out > inffixed.h
 */
void makefixed(void)
{
    unsigned low, size;
    struct inflate_state state;

    fixedtables(&state);
    puts("    /* inffixed.h -- table for decoding fixed codes");
    puts("     * Generated automatically by makefixed().");
    puts("     */");
    puts("");
    puts("    /* WARNING: this file should *not* be used by applications.");
    puts("       It is part of the implementation of this library and is");
    puts("       subject to change. Applications should only use zlib.h.");
    puts("     */");
    puts("");
    size = 1U << 9;
    printf("    static const code lenfix[%u] = {", size);
    low = 0;
    for (;;) {
        if ((low % 7) == 0) printf("\n        ");
        printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
               state.lencode[low].bits, state.lencode[low].val);
        if (++low == size) break;
        putchar(',');
    }
    puts("\n    };");
    size = 1U << 5;
    printf("\n    static const code distfix[%u] = {", size);
    low = 0;
    for (;;) {
        if ((low % 6) == 0) printf("\n        ");
        printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits,
               state.distcode[low].val);
        if (++low == size) break;
        putchar(',');
    }
    puts("\n    };");
}
#endif /* MAKEFIXED */

/*
   Update the window with the last wsize (normally 32K) bytes written before
   returning.  If window does not exist yet, create it.  This is only called
   when a window is already in use, or when output has been written during this
   inflate call, but the end of the deflate stream has not been reached yet.
   It is also called to create a window for dictionary data when a dictionary
   is loaded.

   Providing output buffers larger than 32K to inflate() should provide a speed
   advantage, since only the last 32K of output is copied to the sliding window
   upon return from inflate(), and since all distances after the first 32K of
   output will fall in the output data, making match copies simpler and faster.
   The advantage may be dependent on the size of the processor's data caches.
 */
local int updatewindow(z_streamp strm, const Bytef *end, unsigned copy) {
    struct inflate_state FAR *state;
    unsigned dist;

    state = (struct inflate_state FAR *)strm->state;

    /* if it hasn't been done already, allocate space for the window */
    if (state->window == Z_NULL) {
        state->window = (unsigned char FAR *)
                        ZALLOC(strm, 1U << state->wbits,
                               sizeof(unsigned char));
        if (state->window == Z_NULL) return 1;
    }

    /* if window not in use yet, initialize */
    if (state->wsize == 0) {
        state->wsize = 1U << state->wbits;
        state->wnext = 0;
        state->whave = 0;
    }

    /* copy state->wsize or less output bytes into the circular window */
    if (copy >= state->wsize) {
        zmemcpy(state->window, end - state->wsize, state->wsize);
        state->wnext = 0;
        state->whave = state->wsize;
    }
    else {
        dist = state->wsize - state->wnext;
        if (dist > copy) dist = copy;
        zmemcpy(state->window + state->wnext, end - copy, dist);
        copy -= dist;
        if (copy) {
            zmemcpy(state->window, end - copy, copy);
            state->wnext = copy;
            state->whave = state->wsize;
        }
        else {
            state->wnext += dist;
            if (state->wnext == state->wsize) state->wnext = 0;
            if (state->whave < state->wsize) state->whave += dist;
        }
    }
    return 0;
}

/* Macros for inflate(): */

/* check function to use adler32() for zlib or crc32() for gzip */
#ifdef GUNZIP
#  define UPDATE_CHECK(check, buf, len) \
    (state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
#else
#  define UPDATE_CHECK(check, buf, len) adler32(check, buf, len)
#endif

/* check macros for header crc */
#ifdef GUNZIP
#  define CRC2(check, word) \
    do { \
        hbuf[0] = (unsigned char)(word); \
        hbuf[1] = (unsigned char)((word) >> 8); \
        check = crc32(check, hbuf, 2); \
    } while (0)

#  define CRC4(check, word) \
    do { \
        hbuf[0] = (unsigned char)(word); \
        hbuf[1] = (unsigned char)((word) >> 8); \
        hbuf[2] = (unsigned char)((word) >> 16); \
        hbuf[3] = (unsigned char)((word) >> 24); \
        check = crc32(check, hbuf, 4); \
    } while (0)
#endif

/* Load registers with state in inflate() for speed */
#define LOAD() \
    do { \
        put = strm->next_out; \
        left = strm->avail_out; \
        next = strm->next_in; \
        have = strm->avail_in; \
        hold = state->hold; \
        bits = state->bits; \
    } while (0)

/* Restore state from registers in inflate() */
#define RESTORE() \
    do { \
        strm->next_out = put; \
        strm->avail_out = left; \
        strm->next_in = next; \
        strm->avail_in = have; \
        state->hold = hold; \
        state->bits = bits; \
    } while (0)

/* Clear the input bit accumulator */
#define INITBITS() \
    do { \
        hold = 0; \
        bits = 0; \
    } while (0)

/* Get a byte of input into the bit accumulator, or return from inflate()
   if there is no input available. */
#define PULLBYTE() \
    do { \
        if (have == 0) goto inf_leave; \
        have--; \
        hold += (unsigned long)(*next++) << bits; \
        bits += 8; \
    } while (0)

/* Assure that there are at least n bits in the bit accumulator.  If there is
   not enough available input to do that, then return from inflate(). */
#define NEEDBITS(n) \
    do { \
        while (bits < (unsigned)(n)) \
            PULLBYTE(); \
    } while (0)

/* Return the low n bits of the bit accumulator (n < 16) */
#define BITS(n) \
    ((unsigned)hold & ((1U << (n)) - 1))

/* Remove n bits from the bit accumulator */
#define DROPBITS(n) \
    do { \
        hold >>= (n); \
        bits -= (unsigned)(n); \
    } while (0)

/* Remove zero to seven bits as needed to go to a byte boundary */
#define BYTEBITS() \
    do { \
        hold >>= bits & 7; \
        bits -= bits & 7; \
    } while (0)

/*
   inflate() uses a state machine to process as much input data and generate as
   much output data as possible before returning.  The state machine is
   structured roughly as follows:

    for (;;) switch (state) {
    ...
    case STATEn:
        if (not enough input data or output space to make progress)
            return;
        ... make progress ...
        state = STATEm;
        break;
    ...
    }

   so when inflate() is called again, the same case is attempted again, and
   if the appropriate resources are provided, the machine proceeds to the
   next state.  The NEEDBITS() macro is usually the way the state evaluates
   whether it can proceed or should return.  NEEDBITS() does the return if
   the requested bits are not available.  The typical use of the BITS macros
   is:

        NEEDBITS(n);
        ... do something with BITS(n) ...
        DROPBITS(n);

   where NEEDBITS(n) either returns from inflate() if there isn't enough
   input left to load n bits into the accumulator, or it continues.  BITS(n)
   gives the low n bits in the accumulator.  When done, DROPBITS(n) drops
   the low n bits off the accumulator.  INITBITS() clears the accumulator
   and sets the number of available bits to zero.  BYTEBITS() discards just
   enough bits to put the accumulator on a byte boundary.  After BYTEBITS()
   and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.

   NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
   if there is no input available.  The decoding of variable length codes uses
   PULLBYTE() directly in order to pull just enough bytes to decode the next
   code, and no more.

   Some states loop until they get enough input, making sure that enough
   state information is maintained to continue the loop where it left off
   if NEEDBITS() returns in the loop.  For example, want, need, and keep
   would all have to actually be part of the saved state in case NEEDBITS()
   returns:

    case STATEw:
        while (want < need) {
            NEEDBITS(n);
            keep[want++] = BITS(n);
            DROPBITS(n);
        }
        state = STATEx;
    case STATEx:

   As shown above, if the next state is also the next case, then the break
   is omitted.

   A state may also return if there is not enough output space available to
   complete that state.  Those states are copying stored data, writing a
   literal byte, and copying a matching string.

   When returning, a "goto inf_leave" is used to update the total counters,
   update the check value, and determine whether any progress has been made
   during that inflate() call in order to return the proper return code.
   Progress is defined as a change in either strm->avail_in or strm->avail_out.
   When there is a window, goto inf_leave will update the window with the last
   output written.  If a goto inf_leave occurs in the middle of decompression
   and there is no window currently, goto inf_leave will create one and copy
   output to the window for the next call of inflate().

   In this implementation, the flush parameter of inflate() only affects the
   return code (per zlib.h).  inflate() always writes as much as possible to
   strm->next_out, given the space available and the provided input--the effect
   documented in zlib.h of Z_SYNC_FLUSH.  Furthermore, inflate() always defers
   the allocation of and copying into a sliding window until necessary, which
   provides the effect documented in zlib.h for Z_FINISH when the entire input
   stream available.  So the only thing the flush parameter actually does is:
   when flush is set to Z_FINISH, inflate() cannot return Z_OK.  Instead it
   will return Z_BUF_ERROR if it has not reached the end of the stream.
 */

int ZEXPORT inflate(z_streamp strm, int flush) {
    struct inflate_state FAR *state;
    z_const unsigned char FAR *next;    /* next input */
    unsigned char FAR *put;     /* next output */
    unsigned have, left;        /* available input and output */
    unsigned long hold;         /* bit buffer */
    unsigned bits;              /* bits in bit buffer */
    unsigned in, out;           /* save starting available input and output */
    unsigned copy;              /* number of stored or match bytes to copy */
    unsigned char FAR *from;    /* where to copy match bytes from */
    code here;                  /* current decoding table entry */
    code last;                  /* parent table entry */
    unsigned len;               /* length to copy for repeats, bits to drop */
    int ret;                    /* return code */
#ifdef GUNZIP
    unsigned char hbuf[4];      /* buffer for gzip header crc calculation */
#endif
    static const unsigned short order[19] = /* permutation of code lengths */
        {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};

    if (inflateStateCheck(strm) || strm->next_out == Z_NULL ||
        (strm->next_in == Z_NULL && strm->avail_in != 0))
        return Z_STREAM_ERROR;

    state = (struct inflate_state FAR *)strm->state;
    if (state->mode == TYPE) state->mode = TYPEDO;      /* skip check */
    LOAD();
    in = have;
    out = left;
    ret = Z_OK;
    for (;;)
        switch (state->mode) {
        case HEAD:
            if (state->wrap == 0) {
                state->mode = TYPEDO;
                break;
            }
            NEEDBITS(16);
#ifdef GUNZIP
            if ((state->wrap & 2) && hold == 0x8b1f) {  /* gzip header */
                if (state->wbits == 0)
                    state->wbits = 15;
                state->check = crc32(0L, Z_NULL, 0);
                CRC2(state->check, hold);
                INITBITS();
                state->mode = FLAGS;
                break;
            }
            if (state->head != Z_NULL)
                state->head->done = -1;
            if (!(state->wrap & 1) ||   /* check if zlib header allowed */
#else
            if (
#endif
                ((BITS(8) << 8) + (hold >> 8)) % 31) {
                strm->msg = (z_const char *)"incorrect header check";
                state->mode = BAD;
                break;
            }
            if (BITS(4) != Z_DEFLATED) {
                strm->msg = (z_const char *)"unknown compression method";
                state->mode = BAD;
                break;
            }
            DROPBITS(4);
            len = BITS(4) + 8;
            if (state->wbits == 0)
                state->wbits = len;
            if (len > 15 || len > state->wbits) {
                strm->msg = (z_const char *)"invalid window size";
                state->mode = BAD;
                break;
            }
            state->dmax = 1U << len;
            state->flags = 0;               /* indicate zlib header */
            Tracev((stderr, "inflate:   zlib header ok\n"));
            strm->adler = state->check = adler32(0L, Z_NULL, 0);
            state->mode = hold & 0x200 ? DICTID : TYPE;
            INITBITS();
            break;
#ifdef GUNZIP
        case FLAGS:
            NEEDBITS(16);
            state->flags = (int)(hold);
            if ((state->flags & 0xff) != Z_DEFLATED) {
                strm->msg = (z_const char *)"unknown compression method";
                state->mode = BAD;
                break;
            }
            if (state->flags & 0xe000) {
                strm->msg = (z_const char *)"unknown header flags set";
                state->mode = BAD;
                break;
            }
            if (state->head != Z_NULL)
                state->head->text = (int)((hold >> 8) & 1);
            if ((state->flags & 0x0200) && (state->wrap & 4))
                CRC2(state->check, hold);
            INITBITS();
            state->mode = TIME;
                /* fallthrough */
        case TIME:
            NEEDBITS(32);
            if (state->head != Z_NULL)
                state->head->time = hold;
            if ((state->flags & 0x0200) && (state->wrap & 4))
                CRC4(state->check, hold);
            INITBITS();
            state->mode = OS;
                /* fallthrough */
        case OS:
            NEEDBITS(16);
            if (state->head != Z_NULL) {
                state->head->xflags = (int)(hold & 0xff);
                state->head->os = (int)(hold >> 8);
            }
            if ((state->flags & 0x0200) && (state->wrap & 4))
                CRC2(state->check, hold);
            INITBITS();
            state->mode = EXLEN;
                /* fallthrough */
        case EXLEN:
            if (state->flags & 0x0400) {
                NEEDBITS(16);
                state->length = (unsigned)(hold);
                if (state->head != Z_NULL)
                    state->head->extra_len = (unsigned)hold;
                if ((state->flags & 0x0200) && (state->wrap & 4))
                    CRC2(state->check, hold);
                INITBITS();
            }
            else if (state->head != Z_NULL)
                state->head->extra = Z_NULL;
            state->mode = EXTRA;
                /* fallthrough */
        case EXTRA:
            if (state->flags & 0x0400) {
                copy = state->length;
                if (copy > have) copy = have;
                if (copy) {
                    if (state->head != Z_NULL &&
                        state->head->extra != Z_NULL &&
                        (len = state->head->extra_len - state->length) <
                            state->head->extra_max) {
                        zmemcpy(state->head->extra + len, next,
                                len + copy > state->head->extra_max ?
                                state->head->extra_max - len : copy);
                    }
                    if ((state->flags & 0x0200) && (state->wrap & 4))
                        state->check = crc32(state->check, next, copy);
                    have -= copy;
                    next += copy;
                    state->length -= copy;
                }
                if (state->length) goto inf_leave;
            }
            state->length = 0;
            state->mode = NAME;
                /* fallthrough */
        case NAME:
            if (state->flags & 0x0800) {
                if (have == 0) goto inf_leave;
                copy = 0;
                do {
                    len = (unsigned)(next[copy++]);
                    if (state->head != Z_NULL &&
                            state->head->name != Z_NULL &&
                            state->length < state->head->name_max)
                        state->head->name[state->length++] = (Bytef)len;
                } while (len && copy < have);
                if ((state->flags & 0x0200) && (state->wrap & 4))
                    state->check = crc32(state->check, next, copy);
                have -= copy;
                next += copy;
                if (len) goto inf_leave;
            }
            else if (state->head != Z_NULL)
                state->head->name = Z_NULL;
            state->length = 0;
            state->mode = COMMENT;
                /* fallthrough */
        case COMMENT:
            if (state->flags & 0x1000) {
                if (have == 0) goto inf_leave;
                copy = 0;
                do {
                    len = (unsigned)(next[copy++]);
                    if (state->head != Z_NULL &&
                            state->head->comment != Z_NULL &&
                            state->length < state->head->comm_max)
                        state->head->comment[state->length++] = (Bytef)len;
                } while (len && copy < have);
                if ((state->flags & 0x0200) && (state->wrap & 4))
                    state->check = crc32(state->check, next, copy);
                have -= copy;
                next += copy;
                if (len) goto inf_leave;
            }
            else if (state->head != Z_NULL)
                state->head->comment = Z_NULL;
            state->mode = HCRC;
                /* fallthrough */
        case HCRC:
            if (state->flags & 0x0200) {
                NEEDBITS(16);
                if ((state->wrap & 4) && hold != (state->check & 0xffff)) {
                    strm->msg = (z_const char *)"header crc mismatch";
                    state->mode = BAD;
                    break;
                }
                INITBITS();
            }
            if (state->head != Z_NULL) {
                state->head->hcrc = (int)((state->flags >> 9) & 1);
                state->head->done = 1;
            }
            strm->adler = state->check = crc32(0L, Z_NULL, 0);
            state->mode = TYPE;
            break;
#endif
        case DICTID:
            NEEDBITS(32);
            strm->adler = state->check = ZSWAP32(hold);
            INITBITS();
            state->mode = DICT;
                /* fallthrough */
        case DICT:
            if (state->havedict == 0) {
                RESTORE();
                return Z_NEED_DICT;
            }
            strm->adler = state->check = adler32(0L, Z_NULL, 0);
            state->mode = TYPE;
                /* fallthrough */
        case TYPE:
            if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
                /* fallthrough */
        case TYPEDO:
            if (strm->start_bit == 0)
                strm->start_bit = 8 * (strm->total_in + in - have) - bits;
            if (state->last) {
                strm->stop_bit = 8 * (strm->total_in + in - have) - bits;
                BYTEBITS();
                state->mode = CHECK;
                break;
            }
            NEEDBITS(3);
            state->last = BITS(1);
            if (state->last)
                strm->last_bit = 8 * (strm->total_in + in - have) - bits;
            DROPBITS(1);
            switch (BITS(2)) {
            case 0:                             /* stored block */
                Tracev((stderr, "inflate:     stored block%s\n",
                        state->last ? " (last)" : ""));
                state->mode = STORED;
                break;
            case 1:                             /* fixed block */
                fixedtables(state);
                Tracev((stderr, "inflate:     fixed codes block%s\n",
                        state->last ? " (last)" : ""));
                state->mode = LEN_;             /* decode codes */
                if (flush == Z_TREES) {
                    DROPBITS(2);
                    goto inf_leave;
                }
                break;
            case 2:                             /* dynamic block */
                Tracev((stderr, "inflate:     dynamic codes block%s\n",
                        state->last ? " (last)" : ""));
                state->mode = TABLE;
                break;
            case 3:
                strm->msg = (z_const char *)"invalid block type";
                state->mode = BAD;
            }
            DROPBITS(2);
            break;
        case STORED:
            BYTEBITS();                         /* go to byte boundary */
            NEEDBITS(32);
            if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
                strm->msg = (z_const char *)"invalid stored block lengths";
                state->mode = BAD;
                break;
            }
            state->length = (unsigned)hold & 0xffff;
            Tracev((stderr, "inflate:       stored length %u\n",
                    state->length));
            INITBITS();
            state->mode = COPY_;
            if (flush == Z_TREES) goto inf_leave;
                /* fallthrough */
        case COPY_:
            state->mode = COPY;
                /* fallthrough */
        case COPY:
            copy = state->length;
            if (copy) {
                if (copy > have) copy = have;
                if (copy > left) copy = left;
                if (copy == 0) goto inf_leave;
                zmemcpy(put, next, copy);
                have -= copy;
                next += copy;
                left -= copy;
                put += copy;
                state->length -= copy;
                break;
            }
            Tracev((stderr, "inflate:       stored end\n"));
            state->mode = TYPE;
            break;
        case TABLE:
            NEEDBITS(14);
            state->nlen = BITS(5) + 257;
            DROPBITS(5);
            state->ndist = BITS(5) + 1;
            DROPBITS(5);
            state->ncode = BITS(4) + 4;
            DROPBITS(4);
#ifndef PKZIP_BUG_WORKAROUND
            if (state->nlen > 286 || state->ndist > 30) {
                strm->msg = (z_const char *)"too many length or distance symbols";
                state->mode = BAD;
                break;
            }
#endif
            Tracev((stderr, "inflate:       table sizes ok\n"));
            state->have = 0;
            state->mode = LENLENS;
                /* fallthrough */
        case LENLENS:
            while (state->have < state->ncode) {
                NEEDBITS(3);
                state->lens[order[state->have++]] = (unsigned short)BITS(3);
                DROPBITS(3);
            }
            while (state->have < 19)
                state->lens[order[state->have++]] = 0;
            state->next = state->codes;
            state->lencode = state->distcode = (const code FAR *)(state->next);
            state->lenbits = 7;
            ret = inflate_table(CODES, state->lens, 19, &(state->next),
                                &(state->lenbits), state->work);
            if (ret) {
                strm->msg = (z_const char *)"invalid code lengths set";
                state->mode = BAD;
                break;
            }
            Tracev((stderr, "inflate:       code lengths ok\n"));
            state->have = 0;
            state->mode = CODELENS;
                /* fallthrough */
        case CODELENS:
            while (state->have < state->nlen + state->ndist) {
                for (;;) {
                    here = state->lencode[BITS(state->lenbits)];
                    if ((unsigned)(here.bits) <= bits) break;
                    PULLBYTE();
                }
                if (here.val < 16) {
                    DROPBITS(here.bits);
                    state->lens[state->have++] = here.val;
                }
                else {
                    if (here.val == 16) {
                        NEEDBITS(here.bits + 2);
                        DROPBITS(here.bits);
                        if (state->have == 0) {
                            strm->msg = (z_const char *)"invalid bit length repeat";
                            state->mode = BAD;
                            break;
                        }
                        len = state->lens[state->have - 1];
                        copy = 3 + BITS(2);
                        DROPBITS(2);
                    }
                    else if (here.val == 17) {
                        NEEDBITS(here.bits + 3);
                        DROPBITS(here.bits);
                        len = 0;
                        copy = 3 + BITS(3);
                        DROPBITS(3);
                    }
                    else {
                        NEEDBITS(here.bits + 7);
                        DROPBITS(here.bits);
                        len = 0;
                        copy = 11 + BITS(7);
                        DROPBITS(7);
                    }
                    if (state->have + copy > state->nlen + state->ndist) {
                        strm->msg = (z_const char *)"invalid bit length repeat";
                        state->mode = BAD;
                        break;
                    }
                    while (copy--)
                        state->lens[state->have++] = (unsigned short)len;
                }
            }

            /* handle error breaks in while */
            if (state->mode == BAD) break;

            /* check for end-of-block code (better have one) */
            if (state->lens[256] == 0) {
                strm->msg = (z_const char *)"invalid code -- missing end-of-block";
                state->mode = BAD;
                break;
            }

            /* build code tables -- note: do not change the lenbits or distbits
               values here (9 and 6) without reading the comments in inftrees.h
               concerning the ENOUGH constants, which depend on those values */
            state->next = state->codes;
            state->lencode = (const code FAR *)(state->next);
            state->lenbits = 9;
            ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
                                &(state->lenbits), state->work);
            if (ret) {
                strm->msg = (z_const char *)"invalid literal/lengths set";
                state->mode = BAD;
                break;
            }
            state->distcode = (const code FAR *)(state->next);
            state->distbits = 6;
            ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
                            &(state->next), &(state->distbits), state->work);
            if (ret) {
                strm->msg = (z_const char *)"invalid distances set";
                state->mode = BAD;
                break;
            }
            Tracev((stderr, "inflate:       codes ok\n"));
            state->mode = LEN_;
            if (flush == Z_TREES) goto inf_leave;
                /* fallthrough */
        case LEN_:
            state->mode = LEN;
                /* fallthrough */
        case LEN:
            if (have >= 6 && left >= 258) {
                RESTORE();
                inflate_fast(strm, out);
                LOAD();
                if (state->mode == TYPE)
                    state->back = -1;
                break;
            }
            state->back = 0;
            for (;;) {
                here = state->lencode[BITS(state->lenbits)];
                if ((unsigned)(here.bits) <= bits) break;
                PULLBYTE();
            }
            if (here.op && (here.op & 0xf0) == 0) {
                last = here;
                for (;;) {
                    here = state->lencode[last.val +
                            (BITS(last.bits + last.op) >> last.bits)];
                    if ((unsigned)(last.bits + here.bits) <= bits) break;
                    PULLBYTE();
                }
                DROPBITS(last.bits);
                state->back += last.bits;
            }
            DROPBITS(here.bits);
            state->back += here.bits;
            state->length = (unsigned)here.val;
            if ((int)(here.op) == 0) {
                Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
                        "inflate:         literal '%c'\n" :
                        "inflate:         literal 0x%02x\n", here.val));
                state->mode = LIT;
                break;
            }
            if (here.op & 32) {
                Tracevv((stderr, "inflate:         end of block\n"));
                state->back = -1;
                state->mode = TYPE;
                break;
            }
            if (here.op & 64) {
                strm->msg = (z_const char *)"invalid literal/length code";
                state->mode = BAD;
                break;
            }
            state->extra = (unsigned)(here.op) & 15;
            state->mode = LENEXT;
                /* fallthrough */
        case LENEXT:
            if (state->extra) {
                NEEDBITS(state->extra);
                state->length += BITS(state->extra);
                DROPBITS(state->extra);
                state->back += state->extra;
            }
            Tracevv((stderr, "inflate:         length %u\n", state->length));
            state->was = state->length;
            state->mode = DIST;
                /* fallthrough */
        case DIST:
            for (;;) {
                here = state->distcode[BITS(state->distbits)];
                if ((unsigned)(here.bits) <= bits) break;
                PULLBYTE();
            }
            if ((here.op & 0xf0) == 0) {
                last = here;
                for (;;) {
                    here = state->distcode[last.val +
                            (BITS(last.bits + last.op) >> last.bits)];
                    if ((unsigned)(last.bits + here.bits) <= bits) break;
                    PULLBYTE();
                }
                DROPBITS(last.bits);
                state->back += last.bits;
            }
            DROPBITS(here.bits);
            state->back += here.bits;
            if (here.op & 64) {
                strm->msg = (z_const char *)"invalid distance code";
                state->mode = BAD;
                break;
            }
            state->offset = (unsigned)here.val;
            state->extra = (unsigned)(here.op) & 15;
            state->mode = DISTEXT;
                /* fallthrough */
        case DISTEXT:
            if (state->extra) {
                NEEDBITS(state->extra);
                state->offset += BITS(state->extra);
                DROPBITS(state->extra);
                state->back += state->extra;
            }
#ifdef INFLATE_STRICT
            if (state->offset > state->dmax) {
                strm->msg = (z_const char *)"invalid distance too far back";
                state->mode = BAD;
                break;
            }
#endif
            Tracevv((stderr, "inflate:         distance %u\n", state->offset));
            state->mode = MATCH;
                /* fallthrough */
        case MATCH:
            if (left == 0) goto inf_leave;
            copy = out - left;
            if (state->offset > copy) {         /* copy from window */
                copy = state->offset - copy;
                if (copy > state->whave) {
                    if (state->sane) {
                        strm->msg = (z_const char *)"invalid distance too far back";
                        state->mode = BAD;
                        break;
                    }
#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
                    Trace((stderr, "inflate.c too far\n"));
                    copy -= state->whave;
                    if (copy > state->length) copy = state->length;
                    if (copy > left) copy = left;
                    left -= copy;
                    state->length -= copy;
                    do {
                        *put++ = 0;
                    } while (--copy);
                    if (state->length == 0) state->mode = LEN;
                    break;
#endif
                }
                if (copy > state->wnext) {
                    copy -= state->wnext;
                    from = state->window + (state->wsize - copy);
                }
                else
                    from = state->window + (state->wnext - copy);
                if (copy > state->length) copy = state->length;
            }
            else {                              /* copy from output */
                from = put - state->offset;
                copy = state->length;
            }
            if (copy > left) copy = left;
            left -= copy;
            state->length -= copy;
            do {
                *put++ = *from++;
            } while (--copy);
            if (state->length == 0) state->mode = LEN;
            break;
        case LIT:
            if (left == 0) goto inf_leave;
            *put++ = (unsigned char)(state->length);
            left--;
            state->mode = LEN;
            break;
        case CHECK:
            if (state->wrap) {
                NEEDBITS(32);
                out -= left;
                strm->total_out += out;
                state->total += out;
                if ((state->wrap & 4) && out)
                    strm->adler = state->check =
                        UPDATE_CHECK(state->check, put - out, out);
                out = left;
                if ((state->wrap & 4) && (
#ifdef GUNZIP
                     state->flags ? hold :
#endif
                     ZSWAP32(hold)) != state->check) {
                    strm->msg = (z_const char *)"incorrect data check";
                    state->mode = BAD;
                    break;
                }
                INITBITS();
                Tracev((stderr, "inflate:   check matches trailer\n"));
            }
#ifdef GUNZIP
            state->mode = LENGTH;
                /* fallthrough */
        case LENGTH:
            if (state->wrap && state->flags) {
                NEEDBITS(32);
                if ((state->wrap & 4) && hold != (state->total & 0xffffffff)) {
                    strm->msg = (z_const char *)"incorrect length check";
                    state->mode = BAD;
                    break;
                }
                INITBITS();
                Tracev((stderr, "inflate:   length matches trailer\n"));
            }
#endif
            state->mode = DONE;
                /* fallthrough */
        case DONE:
            ret = Z_STREAM_END;
            goto inf_leave;
        case BAD:
            ret = Z_DATA_ERROR;
            goto inf_leave;
        case MEM:
            return Z_MEM_ERROR;
        case SYNC:
                /* fallthrough */
        default:
            return Z_STREAM_ERROR;
        }

    /*
       Return from inflate(), updating the total counts and the check value.
       If there was no progress during the inflate() call, return a buffer
       error.  Call updatewindow() to create and/or update the window state.
       Note: a memory error from inflate() is non-recoverable.
     */
  inf_leave:
    RESTORE();
    if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
            (state->mode < CHECK || flush != Z_FINISH)))
        if (updatewindow(strm, strm->next_out, out - strm->avail_out)) {
            state->mode = MEM;
            return Z_MEM_ERROR;
        }
    in -= strm->avail_in;
    out -= strm->avail_out;
    strm->total_in += in;
    strm->total_out += out;
    state->total += out;
    if ((state->wrap & 4) && out)
        strm->adler = state->check =
            UPDATE_CHECK(state->check, strm->next_out - out, out);
    strm->data_type = (int)state->bits + (state->last ? 64 : 0) +
                      (state->mode == TYPE ? 128 : 0) +
                      (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
    if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
        ret = Z_BUF_ERROR;
    return ret;
}

int ZEXPORT inflateEnd(z_streamp strm) {
    struct inflate_state FAR *state;
    if (inflateStateCheck(strm))
        return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (state->window != Z_NULL) ZFREE(strm, state->window);
    ZFREE(strm, strm->state);
    strm->state = Z_NULL;
    Tracev((stderr, "inflate: end\n"));
    return Z_OK;
}

#ifdef NOVGZ

int ZEXPORT inflateGetDictionary(z_streamp strm, Bytef *dictionary,
                                 uInt *dictLength) {
    struct inflate_state FAR *state;

    /* check state */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;

    /* copy dictionary */
    if (state->whave && dictionary != Z_NULL) {
        zmemcpy(dictionary, state->window + state->wnext,
                state->whave - state->wnext);
        zmemcpy(dictionary + state->whave - state->wnext,
                state->window, state->wnext);
    }
    if (dictLength != Z_NULL)
        *dictLength = state->whave;
    return Z_OK;
}

int ZEXPORT inflateSetDictionary(z_streamp strm, const Bytef *dictionary,
                                 uInt dictLength) {
    struct inflate_state FAR *state;
    unsigned long dictid;
    int ret;

    /* check state */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (state->wrap != 0 && state->mode != DICT)
        return Z_STREAM_ERROR;

    /* check for correct dictionary identifier */
    if (state->mode == DICT) {
        dictid = adler32(0L, Z_NULL, 0);
        dictid = adler32(dictid, dictionary, dictLength);
        if (dictid != state->check)
            return Z_DATA_ERROR;
    }

    /* copy dictionary to window using updatewindow(), which will amend the
       existing dictionary if appropriate */
    ret = updatewindow(strm, dictionary + dictLength, dictLength);
    if (ret) {
        state->mode = MEM;
        return Z_MEM_ERROR;
    }
    state->havedict = 1;
    Tracev((stderr, "inflate:   dictionary set\n"));
    return Z_OK;
}

int ZEXPORT inflateGetHeader(z_streamp strm, gz_headerp head) {
    struct inflate_state FAR *state;

    /* check state */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;

    /* save header structure */
    state->head = head;
    head->done = 0;
    return Z_OK;
}

/*
   Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff.  Return when found
   or when out of input.  When called, *have is the number of pattern bytes
   found in order so far, in 0..3.  On return *have is updated to the new
   state.  If on return *have equals four, then the pattern was found and the
   return value is how many bytes were read including the last byte of the
   pattern.  If *have is less than four, then the pattern has not been found
   yet and the return value is len.  In the latter case, syncsearch() can be
   called again with more data and the *have state.  *have is initialized to
   zero for the first call.
 */
local unsigned syncsearch(unsigned FAR *have, const unsigned char FAR *buf,
                          unsigned len) {
    unsigned got;
    unsigned next;

    got = *have;
    next = 0;
    while (next < len && got < 4) {
        if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
            got++;
        else if (buf[next])
            got = 0;
        else
            got = 4 - got;
        next++;
    }
    *have = got;
    return next;
}

int ZEXPORT inflateSync(z_streamp strm) {
    unsigned len;               /* number of bytes to look at or looked at */
    int flags;                  /* temporary to save header status */
    unsigned long in, out;      /* temporary to save total_in and total_out */
    unsigned char buf[4];       /* to restore bit buffer to byte string */
    struct inflate_state FAR *state;

    /* check parameters */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;

    /* if first time, start search in bit buffer */
    if (state->mode != SYNC) {
        state->mode = SYNC;
        state->hold >>= state->bits & 7;
        state->bits -= state->bits & 7;
        len = 0;
        while (state->bits >= 8) {
            buf[len++] = (unsigned char)(state->hold);
            state->hold >>= 8;
            state->bits -= 8;
        }
        state->have = 0;
        syncsearch(&(state->have), buf, len);
    }

    /* search available input */
    len = syncsearch(&(state->have), strm->next_in, strm->avail_in);
    strm->avail_in -= len;
    strm->next_in += len;
    strm->total_in += len;

    /* return no joy or set up to restart inflate() on a new block */
    if (state->have != 4) return Z_DATA_ERROR;
    if (state->flags == -1)
        state->wrap = 0;    /* if no header yet, treat as raw */
    else
        state->wrap &= ~4;  /* no point in computing a check value now */
    flags = state->flags;
    in = strm->total_in;  out = strm->total_out;
    inflateReset(strm);
    strm->total_in = in;  strm->total_out = out;
    state->flags = flags;
    state->mode = TYPE;
    return Z_OK;
}

/*
   Returns true if inflate is currently at the end of a block generated by
   Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
   implementation to provide an additional safety check. PPP uses
   Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
   block. When decompressing, PPP checks that at the end of input packet,
   inflate is waiting for these length bytes.
 */
int ZEXPORT inflateSyncPoint(z_streamp strm) {
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    return state->mode == STORED && state->bits == 0;
}

int ZEXPORT inflateCopy(z_streamp dest, z_streamp source) {
    struct inflate_state FAR *state;
    struct inflate_state FAR *copy;
    unsigned char FAR *window;
    unsigned wsize;

    /* check input */
    if (inflateStateCheck(source) || dest == Z_NULL)
        return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)source->state;

    /* allocate space */
    copy = (struct inflate_state FAR *)
           ZALLOC(source, 1, sizeof(struct inflate_state));
    if (copy == Z_NULL) return Z_MEM_ERROR;
    window = Z_NULL;
    if (state->window != Z_NULL) {
        window = (unsigned char FAR *)
                 ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
        if (window == Z_NULL) {
            ZFREE(source, copy);
            return Z_MEM_ERROR;
        }
    }

    /* copy state */
    zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
    zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
    copy->strm = dest;
    if (state->lencode >= state->codes &&
        state->lencode <= state->codes + ENOUGH - 1) {
        copy->lencode = copy->codes + (state->lencode - state->codes);
        copy->distcode = copy->codes + (state->distcode - state->codes);
    }
    copy->next = copy->codes + (state->next - state->codes);
    if (window != Z_NULL) {
        wsize = 1U << state->wbits;
        zmemcpy(window, state->window, wsize);
    }
    copy->window = window;
    dest->state = (struct internal_state FAR *)copy;
    return Z_OK;
}

int ZEXPORT inflateUndermine(z_streamp strm, int subvert) {
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
    state->sane = !subvert;
    return Z_OK;
#else
    (void)subvert;
    state->sane = 1;
    return Z_DATA_ERROR;
#endif
}

int ZEXPORT inflateValidate(z_streamp strm, int check) {
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (check && state->wrap)
        state->wrap |= 4;
    else
        state->wrap &= ~4;
    return Z_OK;
}

long ZEXPORT inflateMark(z_streamp strm) {
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm))
        return -(1L << 16);
    state = (struct inflate_state FAR *)strm->state;
    return (long)(((unsigned long)((long)state->back)) << 16) +
        (state->mode == COPY ? state->length :
            (state->mode == MATCH ? state->was - state->length : 0));
}

unsigned long ZEXPORT inflateCodesUsed(z_streamp strm) {
    struct inflate_state FAR *state;
    if (inflateStateCheck(strm)) return (unsigned long)-1;
    state = (struct inflate_state FAR *)strm->state;
    return (unsigned long)(state->next - state->codes);
}

#endif /* NOVGZ */

		varnish-cache/lib/libvgz/inflate.c
0		/* inflate.c -- zlib decompression
1		* Copyright (C) 1995-2022 Mark Adler
2		* For conditions of distribution and use, see copyright notice in zlib.h
3		*/
4
5		/*
6		* Change history:
7		*
8		* 1.2.beta0 24 Nov 2002
9		* - First version -- complete rewrite of inflate to simplify code, avoid
10		* creation of window when not needed, minimize use of window when it is
11		* needed, make inffast.c even faster, implement gzip decoding, and to
12		* improve code readability and style over the previous zlib inflate code
13		*
14		* 1.2.beta1 25 Nov 2002
15		* - Use pointers for available input and output checking in inffast.c
16		* - Remove input and output counters in inffast.c
17		* - Change inffast.c entry and loop from avail_in >= 7 to >= 6
18		* - Remove unnecessary second byte pull from length extra in inffast.c
19		* - Unroll direct copy to three copies per loop in inffast.c
20		*
21		* 1.2.beta2 4 Dec 2002
22		* - Change external routine names to reduce potential conflicts
23		* - Correct filename to inffixed.h for fixed tables in inflate.c
24		* - Make hbuf[] unsigned char to match parameter type in inflate.c
25		* - Change strm->next_out[-state->offset] to *(strm->next_out - state->offset)
26		* to avoid negation problem on Alphas (64 bit) in inflate.c
27		*
28		* 1.2.beta3 22 Dec 2002
29		* - Add comments on state->bits assertion in inffast.c
30		* - Add comments on op field in inftrees.h
31		* - Fix bug in reuse of allocated window after inflateReset()
32		* - Remove bit fields--back to byte structure for speed
33		* - Remove distance extra == 0 check in inflate_fast()--only helps for lengths
34		* - Change post-increments to pre-increments in inflate_fast(), PPC biased?
35		* - Add compile time option, POSTINC, to use post-increments instead (Intel?)
36		* - Make MATCH copy in inflate() much faster for when inflate_fast() not used
37		* - Use local copies of stream next and avail values, as well as local bit
38		* buffer and bit count in inflate()--for speed when inflate_fast() not used
39		*
40		* 1.2.beta4 1 Jan 2003
41		* - Split ptr - 257 statements in inflate_table() to avoid compiler warnings
42		* - Move a comment on output buffer sizes from inffast.c to inflate.c
43		* - Add comments in inffast.c to introduce the inflate_fast() routine
44		* - Rearrange window copies in inflate_fast() for speed and simplification
45		* - Unroll last copy for window match in inflate_fast()
46		* - Use local copies of window variables in inflate_fast() for speed
47		* - Pull out common wnext == 0 case for speed in inflate_fast()
48		* - Make op and len in inflate_fast() unsigned for consistency
49		* - Add FAR to lcode and dcode declarations in inflate_fast()
50		* - Simplified bad distance check in inflate_fast()
51		* - Added inflateBackInit(), inflateBack(), and inflateBackEnd() in new
52		* source file infback.c to provide a call-back interface to inflate for
53		* programs like gzip and unzip -- uses window as output buffer to avoid
54		* window copying
55		*
56		* 1.2.beta5 1 Jan 2003
57		* - Improved inflateBack() interface to allow the caller to provide initial
58		* input in strm.
59		* - Fixed stored blocks bug in inflateBack()
60		*
61		* 1.2.beta6 4 Jan 2003
62		* - Added comments in inffast.c on effectiveness of POSTINC
63		* - Typecasting all around to reduce compiler warnings
64		* - Changed loops from while (1) or do {} while (1) to for (;;), again to
65		* make compilers happy
66		* - Changed type of window in inflateBackInit() to unsigned char *
67		*
68		* 1.2.beta7 27 Jan 2003
69		* - Changed many types to unsigned or unsigned short to avoid warnings
70		* - Added inflateCopy() function
71		*
72		* 1.2.0 9 Mar 2003
73		* - Changed inflateBack() interface to provide separate opaque descriptors
74		* for the in() and out() functions
75		* - Changed inflateBack() argument and in_func typedef to swap the length
76		* and buffer address return values for the input function
77		* - Check next_in and next_out for Z_NULL on entry to inflate()
78		*
79		* The history for versions after 1.2.0 are in ChangeLog in zlib distribution.
80		*/
81
82		#include "zutil.h"
83		#include "inftrees.h"
84		#include "inflate.h"
85		#include "inffast.h"
86
87		#ifdef MAKEFIXED
88		# ifndef BUILDFIXED
89		# define BUILDFIXED
90		# endif
91		#endif
92
93	77900	local int inflateStateCheck(z_streamp strm) {
94		struct inflate_state FAR *state;
95	155800	if (strm == Z_NULL \|\|
96	77900	strm->zalloc == (alloc_func)0 \|\| strm->zfree == (free_func)0)
97	0	return 1;
98	77900	state = (struct inflate_state FAR *)strm->state;
99	155800	if (state == Z_NULL \|\| state->strm != strm \|\|
100	77900	state->mode < HEAD \|\| state->mode > SYNC)
101	0	return 1;
102	77900	return 0;
103	77900	}
104
105	10800	int ZEXPORT inflateResetKeep(z_streamp strm) {
106		struct inflate_state FAR *state;
107
108	10800	if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
109	10800	state = (struct inflate_state FAR *)strm->state;
110	10800	strm->total_in = strm->total_out = state->total = 0;
111	10800	strm->start_bit = strm->stop_bit = strm->last_bit = 0;
112	10800	strm->msg = Z_NULL;
113	10800	if (state->wrap) /* to support ill-conceived Java test suite */
114	10800	strm->adler = state->wrap & 1;
115	10800	state->mode = HEAD;
116	10800	state->last = 0;
117	10800	state->havedict = 0;
118	10800	state->flags = -1;
119	10800	state->dmax = 32768U;
120	10800	state->head = Z_NULL;
121	10800	state->hold = 0;
122	10800	state->bits = 0;
123	10800	state->lencode = state->distcode = state->next = state->codes;
124	10800	state->sane = 1;
125	10800	state->back = -1;
126		Tracev((stderr, "inflate: reset\n"));
127	10800	return Z_OK;
128	10800	}
129
130	10800	int ZEXPORT inflateReset(z_streamp strm) {
131		struct inflate_state FAR *state;
132
133	10800	if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
134	10800	state = (struct inflate_state FAR *)strm->state;
135	10800	state->wsize = 0;
136	10800	state->whave = 0;
137	10800	state->wnext = 0;
138	10800	return inflateResetKeep(strm);
139	10800	}
140
141	10800	int ZEXPORT inflateReset2(z_streamp strm, int windowBits) {
142		int wrap;
143		struct inflate_state FAR *state;
144
145		/* get the state */
146	10800	if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
147	10800	state = (struct inflate_state FAR *)strm->state;
148
149		/* extract wrap request from windowBits parameter */
150	10800	if (windowBits < 0) {
151	0	if (windowBits < -15)
152	0	return Z_STREAM_ERROR;
153	0	wrap = 0;
154	0	windowBits = -windowBits;
155	0	}
156		else {
157	10800	wrap = (windowBits >> 4) + 5;
158		#ifdef GUNZIP
159	10800	if (windowBits < 48)
160	10800	windowBits &= 15;
161		#endif
162		}
163
164		/* set number of window bits, free window if different */
165	10800	if (windowBits && (windowBits < 8 \|\| windowBits > 15))
166	0	return Z_STREAM_ERROR;
167	10800	if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
168	0	ZFREE(strm, state->window);
169	0	state->window = Z_NULL;
170	0	}
171
172		/* update state and reset the rest of it */
173	10800	state->wrap = wrap;
174	10800	state->wbits = (unsigned)windowBits;
175	10800	return inflateReset(strm);
176	10800	}
177
178	10800	int ZEXPORT inflateInit2_(z_streamp strm, int windowBits,
179		const char *version, int stream_size) {
180		int ret;
181		struct inflate_state FAR *state;
182
183	10800	if (version == Z_NULL \|\| version[0] != ZLIB_VERSION[0] \|\|
184	10800	stream_size != (int)(sizeof(z_stream)))
185	0	return Z_VERSION_ERROR;
186	10800	if (strm == Z_NULL) return Z_STREAM_ERROR;
187	10800	strm->msg = Z_NULL; /* in case we return an error */
188	10800	if (strm->zalloc == (alloc_func)0) {
189		#ifdef Z_SOLO
190		return Z_STREAM_ERROR;
191		#else
192	10800	strm->zalloc = zcalloc;
193	10800	strm->opaque = (voidpf)0;
194		#endif
195	10800	}
196	10800	if (strm->zfree == (free_func)0)
197		#ifdef Z_SOLO
198		return Z_STREAM_ERROR;
199		#else
200	10800	strm->zfree = zcfree;
201		#endif
202	10800	state = (struct inflate_state FAR *)
203	10800	ZALLOC(strm, 1, sizeof(struct inflate_state));
204	10800	if (state == Z_NULL) return Z_MEM_ERROR;
205		Tracev((stderr, "inflate: allocated\n"));
206	10800	strm->state = (struct internal_state FAR *)state;
207	10800	state->strm = strm;
208	10800	state->window = Z_NULL;
209	10800	state->mode = HEAD; /* to pass state test in inflateReset2() */
210	10800	ret = inflateReset2(strm, windowBits);
211	10800	if (ret != Z_OK) {
212	0	ZFREE(strm, state);
213	0	strm->state = Z_NULL;
214	0	}
215	10800	return ret;
216	10800	}
217
218		#ifdef NOVGZ
219
220		int ZEXPORT inflateInit_(z_streamp strm, const char *version,
221		int stream_size) {
222		return inflateInit2_(strm, DEF_WBITS, version, stream_size);
223		}
224
225		int ZEXPORT inflatePrime(z_streamp strm, int bits, int value) {
226		struct inflate_state FAR *state;
227
228		if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
229		if (bits == 0)
230		return Z_OK;
231		state = (struct inflate_state FAR *)strm->state;
232		if (bits < 0) {
233		state->hold = 0;
234		state->bits = 0;
235		return Z_OK;
236		}
237		if (bits > 16 \|\| state->bits + (uInt)bits > 32) return Z_STREAM_ERROR;
238		value &= (1L << bits) - 1;
239		state->hold += (unsigned)value << state->bits;
240		state->bits += (uInt)bits;
241		return Z_OK;
242		}
243
244		#endif /* NOVGZ */
245
246		/*
247		Return state with length and distance decoding tables and index sizes set to
248		fixed code decoding. Normally this returns fixed tables from inffixed.h.
249		If BUILDFIXED is defined, then instead this routine builds the tables the
250		first time it's called, and returns those tables the first time and
251		thereafter. This reduces the size of the code by about 2K bytes, in
252		exchange for a little execution time. However, BUILDFIXED should not be
253		used for threaded applications, since the rewriting of the tables and virgin
254		may not be thread-safe.
255		*/
256	16800	local void fixedtables(struct inflate_state FAR *state) {
257		#ifdef BUILDFIXED
258		static int virgin = 1;
259		static code lenfix, distfix;
260		static code fixed[544];
261
262		/* build fixed huffman tables if first call (may not be thread safe) */
263		if (virgin) {
264		unsigned sym, bits;
265		static code *next;
266
267		/* literal/length table */
268		sym = 0;
269		while (sym < 144) state->lens[sym++] = 8;
270		while (sym < 256) state->lens[sym++] = 9;
271		while (sym < 280) state->lens[sym++] = 7;
272		while (sym < 288) state->lens[sym++] = 8;
273		next = fixed;
274		lenfix = next;
275		bits = 9;
276		inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
277
278		/* distance table */
279		sym = 0;
280		while (sym < 32) state->lens[sym++] = 5;
281		distfix = next;
282		bits = 5;
283		inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
284
285		/* do this just once */
286		virgin = 0;
287		}
288		#else /* !BUILDFIXED */
289		# include "inffixed.h"
290		#endif /* BUILDFIXED */
291		state->lencode = lenfix;
292		state->lenbits = 9;
293		state->distcode = distfix;
294		state->distbits = 5;
295		}
296
297		#ifdef MAKEFIXED
298		#include <stdio.h>
299
300		/*
301		Write out the inffixed.h that is #include'd above. Defining MAKEFIXED also
302		defines BUILDFIXED, so the tables are built on the fly. makefixed() writes
303		those tables to stdout, which would be piped to inffixed.h. A small program
304		can simply call makefixed to do this:
305
306		void makefixed(void);
307
308		int main(void)
309		{
310		makefixed();
311		return 0;
312		}
313
314		Then that can be linked with zlib built with MAKEFIXED defined and run:
315
316		a.out > inffixed.h
317		*/
318		void makefixed(void)
319		{
320		unsigned low, size;
321		struct inflate_state state;
322
323		fixedtables(&state);
324		puts(" /* inffixed.h -- table for decoding fixed codes");
325		puts(" * Generated automatically by makefixed().");
326		puts(" */");
327		puts("");
328		puts(" /* WARNING: this file should not be used by applications.");
329		puts(" It is part of the implementation of this library and is");
330		puts(" subject to change. Applications should only use zlib.h.");
331		puts(" */");
332		puts("");
333		size = 1U << 9;
334		printf(" static const code lenfix[%u] = {", size);
335		low = 0;
336		for (;;) {
337		if ((low % 7) == 0) printf("\n ");
338		printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
339		state.lencode[low].bits, state.lencode[low].val);
340		if (++low == size) break;
341		putchar(',');
342		}
343		puts("\n };");
344		size = 1U << 5;
345		printf("\n static const code distfix[%u] = {", size);
346		low = 0;
347		for (;;) {
348		if ((low % 6) == 0) printf("\n ");
349		printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits,
350		state.distcode[low].val);
351		if (++low == size) break;
352		putchar(',');
353		}
354		puts("\n };");
355		}
356		#endif /* MAKEFIXED */
357
358		/*
359		Update the window with the last wsize (normally 32K) bytes written before
360		returning. If window does not exist yet, create it. This is only called
361		when a window is already in use, or when output has been written during this
362		inflate call, but the end of the deflate stream has not been reached yet.
363		It is also called to create a window for dictionary data when a dictionary
364		is loaded.
365
366		Providing output buffers larger than 32K to inflate() should provide a speed
367		advantage, since only the last 32K of output is copied to the sliding window
368		upon return from inflate(), and since all distances after the first 32K of
369		output will fall in the output data, making match copies simpler and faster.
370		The advantage may be dependent on the size of the processor's data caches.
371		*/
372	25025	local int updatewindow(z_streamp strm, const Bytef *end, unsigned copy) {
373		struct inflate_state FAR *state;
374		unsigned dist;
375
376	25025	state = (struct inflate_state FAR *)strm->state;
377
378		/* if it hasn't been done already, allocate space for the window */
379	25025	if (state->window == Z_NULL) {
380	2687	state->window = (unsigned char FAR *)
381	2687	ZALLOC(strm, 1U << state->wbits,
382		sizeof(unsigned char));
383	2687	if (state->window == Z_NULL) return 1;
384	2687	}
385
386		/* if window not in use yet, initialize */
387	25025	if (state->wsize == 0) {
388	2687	state->wsize = 1U << state->wbits;
389	2687	state->wnext = 0;
390	2687	state->whave = 0;
391	2687	}
392
393		/* copy state->wsize or less output bytes into the circular window */
394	25025	if (copy >= state->wsize) {
395	0	zmemcpy(state->window, end - state->wsize, state->wsize);
396	0	state->wnext = 0;
397	0	state->whave = state->wsize;
398	0	}
399		else {
400	25025	dist = state->wsize - state->wnext;
401	25025	if (dist > copy) dist = copy;
402	25025	zmemcpy(state->window + state->wnext, end - copy, dist);
403	25025	copy -= dist;
404	25025	if (copy) {
405	0	zmemcpy(state->window, end - copy, copy);
406	0	state->wnext = copy;
407	0	state->whave = state->wsize;
408	0	}
409		else {
410	25025	state->wnext += dist;
411	25025	if (state->wnext == state->wsize) state->wnext = 0;
412	25025	if (state->whave < state->wsize) state->whave += dist;
413		}
414		}
415	25025	return 0;
416	25025	}
417
418		/* Macros for inflate(): */
419
420		/* check function to use adler32() for zlib or crc32() for gzip */
421		#ifdef GUNZIP
422		# define UPDATE_CHECK(check, buf, len) \
423		(state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
424		#else
425		# define UPDATE_CHECK(check, buf, len) adler32(check, buf, len)
426		#endif
427
428		/* check macros for header crc */
429		#ifdef GUNZIP
430		# define CRC2(check, word) \
431		do { \
432		hbuf[0] = (unsigned char)(word); \
433		hbuf[1] = (unsigned char)((word) >> 8); \
434		check = crc32(check, hbuf, 2); \
435		} while (0)
436
437		# define CRC4(check, word) \
438		do { \
439		hbuf[0] = (unsigned char)(word); \
440		hbuf[1] = (unsigned char)((word) >> 8); \
441		hbuf[2] = (unsigned char)((word) >> 16); \
442		hbuf[3] = (unsigned char)((word) >> 24); \
443		check = crc32(check, hbuf, 4); \
444		} while (0)
445		#endif
446
447		/* Load registers with state in inflate() for speed */
448		#define LOAD() \
449		do { \
450		put = strm->next_out; \
451		left = strm->avail_out; \
452		next = strm->next_in; \
453		have = strm->avail_in; \
454		hold = state->hold; \
455		bits = state->bits; \
456		} while (0)
457
458		/* Restore state from registers in inflate() */
459		#define RESTORE() \
460		do { \
461		strm->next_out = put; \
462		strm->avail_out = left; \
463		strm->next_in = next; \
464		strm->avail_in = have; \
465		state->hold = hold; \
466		state->bits = bits; \
467		} while (0)
468
469		/* Clear the input bit accumulator */
470		#define INITBITS() \
471		do { \
472		hold = 0; \
473		bits = 0; \
474		} while (0)
475
476		/* Get a byte of input into the bit accumulator, or return from inflate()
477		if there is no input available. */
478		#define PULLBYTE() \
479		do { \
480		if (have == 0) goto inf_leave; \
481		have--; \
482		hold += (unsigned long)(*next++) << bits; \
483		bits += 8; \
484		} while (0)
485
486		/* Assure that there are at least n bits in the bit accumulator. If there is
487		not enough available input to do that, then return from inflate(). */
488		#define NEEDBITS(n) \
489		do { \
490		while (bits < (unsigned)(n)) \
491		PULLBYTE(); \
492		} while (0)
493
494		/* Return the low n bits of the bit accumulator (n < 16) */
495		#define BITS(n) \
496		((unsigned)hold & ((1U << (n)) - 1))
497
498		/* Remove n bits from the bit accumulator */
499		#define DROPBITS(n) \