/* inflate.h -- internal inflate state definition

 * Copyright (C) 1995-2016 Mark Adler

 * For conditions of distribution and use, see copyright notice in zlib.h

 */

/* WARNING: this file should *not* be used by applications. It is

   part of the implementation of the compression library and is

   subject to change. Applications should only use zlib.h.

 */

/* define NO_GZIP when compiling if you want to disable gzip header and

   trailer decoding by inflate().  NO_GZIP would be used to avoid linking in

   the crc code when it is not needed.  For shared libraries, gzip decoding

   should be left enabled. */

#ifndef NO_GZIP

#  define GUNZIP

#endif

/* Possible inflate modes between inflate() calls */

typedef enum {

    HEAD = 16180,   /* i: waiting for magic header */

    FLAGS,      /* i: waiting for method and flags (gzip) */

    TIME,       /* i: waiting for modification time (gzip) */

    OS,         /* i: waiting for extra flags and operating system (gzip) */

    EXLEN,      /* i: waiting for extra length (gzip) */

    EXTRA,      /* i: waiting for extra bytes (gzip) */

    NAME,       /* i: waiting for end of file name (gzip) */

    COMMENT,    /* i: waiting for end of comment (gzip) */

    HCRC,       /* i: waiting for header crc (gzip) */

    DICTID,     /* i: waiting for dictionary check value */

    DICT,       /* waiting for inflateSetDictionary() call */

        TYPE,       /* i: waiting for type bits, including last-flag bit */

        TYPEDO,     /* i: same, but skip check to exit inflate on new block */

        STORED,     /* i: waiting for stored size (length and complement) */

        COPY_,      /* i/o: same as COPY below, but only first time in */

        COPY,       /* i/o: waiting for input or output to copy stored block */

        TABLE,      /* i: waiting for dynamic block table lengths */

        LENLENS,    /* i: waiting for code length code lengths */

        CODELENS,   /* i: waiting for length/lit and distance code lengths */

            LEN_,       /* i: same as LEN below, but only first time in */

            LEN,        /* i: waiting for length/lit/eob code */

            LENEXT,     /* i: waiting for length extra bits */

            DIST,       /* i: waiting for distance code */

            DISTEXT,    /* i: waiting for distance extra bits */

            MATCH,      /* o: waiting for output space to copy string */

            LIT,        /* o: waiting for output space to write literal */

    CHECK,      /* i: waiting for 32-bit check value */

    LENGTH,     /* i: waiting for 32-bit length (gzip) */

    DONE,       /* finished check, done -- remain here until reset */

    BAD,        /* got a data error -- remain here until reset */

    MEM,        /* got an inflate() memory error -- remain here until reset */

    SYNC        /* looking for synchronization bytes to restart inflate() */

} inflate_mode;

/*

    State transitions between above modes -

    (most modes can go to BAD or MEM on error -- not shown for clarity)

    Process header:

        HEAD -> (gzip) or (zlib) or (raw)

        (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT ->

                  HCRC -> TYPE

        (zlib) -> DICTID or TYPE

        DICTID -> DICT -> TYPE

        (raw) -> TYPEDO

    Read deflate blocks:

            TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK

            STORED -> COPY_ -> COPY -> TYPE

            TABLE -> LENLENS -> CODELENS -> LEN_

            LEN_ -> LEN

    Read deflate codes in fixed or dynamic block:

                LEN -> LENEXT or LIT or TYPE

                LENEXT -> DIST -> DISTEXT -> MATCH -> LEN

                LIT -> LEN

    Process trailer:

        CHECK -> LENGTH -> DONE

 */

/* State maintained between inflate() calls -- approximately 7K bytes, not

   including the allocated sliding window, which is up to 32K bytes. */

struct inflate_state {

    z_streamp strm;             /* pointer back to this zlib stream */

    inflate_mode mode;          /* current inflate mode */

    int last;                   /* true if processing last block */

    int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip,

                                   bit 2 true to validate check value */

    int havedict;               /* true if dictionary provided */

    int flags;                  /* gzip header method and flags (0 if zlib) */

    unsigned dmax;              /* zlib header max distance (INFLATE_STRICT) */

    unsigned long check;        /* protected copy of check value */

    unsigned long total;        /* protected copy of output count */

    gz_headerp head;            /* where to save gzip header information */

        /* sliding window */

    unsigned wbits;             /* log base 2 of requested window size */

    unsigned wsize;             /* window size or zero if not using window */

    unsigned whave;             /* valid bytes in the window */

    unsigned wnext;             /* window write index */

    unsigned char FAR *window;  /* allocated sliding window, if needed */

        /* bit accumulator */

    unsigned long hold;         /* input bit accumulator */

    unsigned bits;              /* number of bits in "in" */

        /* for string and stored block copying */

    unsigned length;            /* literal or length of data to copy */

    unsigned offset;            /* distance back to copy string from */

        /* for table and code decoding */

    unsigned extra;             /* extra bits needed */

        /* fixed and dynamic code tables */

    code const FAR *lencode;    /* starting table for length/literal codes */

    code const FAR *distcode;   /* starting table for distance codes */

    unsigned lenbits;           /* index bits for lencode */

    unsigned distbits;          /* index bits for distcode */

        /* dynamic table building */

    unsigned ncode;             /* number of code length code lengths */

    unsigned nlen;              /* number of length code lengths */

    unsigned ndist;             /* number of distance code lengths */

    unsigned have;              /* number of code lengths in lens[] */

    code FAR *next;             /* next available space in codes[] */

    unsigned short lens[320];   /* temporary storage for code lengths */

    unsigned short work[288];   /* work area for code table building */

    code codes[ENOUGH];         /* space for code tables */

    int sane;                   /* if false, allow invalid distance too far */

    int back;                   /* bits back of last unprocessed length/lit */

    unsigned was;               /* initial length of match */

};