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v 3.1.0

    1: /* inflate.h -- internal inflate state definition
    2:  * Copyright (C) 1995-2009 Mark Adler
    3:  * For conditions of distribution and use, see copyright notice in zlib.h
    4:  */
    5: 
    6: /* WARNING: this file should *not* be used by applications. It is
    7:    part of the implementation of the compression library and is
    8:    subject to change. Applications should only use zlib.h.
    9:  */
   10: 
   11: /* define NO_GZIP when compiling if you want to disable gzip header and
   12:    trailer decoding by inflate().  NO_GZIP would be used to avoid linking in
   13:    the crc code when it is not needed.  For shared libraries, gzip decoding
   14:    should be left enabled. */
   15: #ifndef NO_GZIP
   16: #  define GUNZIP
   17: #endif
   18: 
   19: #ifdef BAD /* For AIX */
   20: #undef BAD
   21: #endif
   22: 
   23: /* Possible inflate modes between inflate() calls */
   24: typedef enum {
   25:     HEAD,       /* i: waiting for magic header */
   26:     FLAGS,      /* i: waiting for method and flags (gzip) */
   27:     TIME,       /* i: waiting for modification time (gzip) */
   28:     OS,         /* i: waiting for extra flags and operating system (gzip) */
   29:     EXLEN,      /* i: waiting for extra length (gzip) */
   30:     EXTRA,      /* i: waiting for extra bytes (gzip) */
   31:     NAME,       /* i: waiting for end of file name (gzip) */
   32:     COMMENT,    /* i: waiting for end of comment (gzip) */
   33:     HCRC,       /* i: waiting for header crc (gzip) */
   34:     DICTID,     /* i: waiting for dictionary check value */
   35:     DICT,       /* waiting for inflateSetDictionary() call */
   36:         TYPE,       /* i: waiting for type bits, including last-flag bit */
   37:         TYPEDO,     /* i: same, but skip check to exit inflate on new block */
   38:         STORED,     /* i: waiting for stored size (length and complement) */
   39:         COPY_,      /* i/o: same as COPY below, but only first time in */
   40:         COPY,       /* i/o: waiting for input or output to copy stored block */
   41:         TABLE,      /* i: waiting for dynamic block table lengths */
   42:         LENLENS,    /* i: waiting for code length code lengths */
   43:         CODELENS,   /* i: waiting for length/lit and distance code lengths */
   44:             LEN_,       /* i: same as LEN below, but only first time in */
   45:             LEN,        /* i: waiting for length/lit/eob code */
   46:             LENEXT,     /* i: waiting for length extra bits */
   47:             DIST,       /* i: waiting for distance code */
   48:             DISTEXT,    /* i: waiting for distance extra bits */
   49:             MATCH,      /* o: waiting for output space to copy string */
   50:             LIT,        /* o: waiting for output space to write literal */
   51:     CHECK,      /* i: waiting for 32-bit check value */
   52:     LENGTH,     /* i: waiting for 32-bit length (gzip) */
   53:     DONE,       /* finished check, done -- remain here until reset */
   54:     BAD,        /* got a data error -- remain here until reset */
   55:     MEM,        /* got an inflate() memory error -- remain here until reset */
   56:     SYNC        /* looking for synchronization bytes to restart inflate() */
   57: } inflate_mode;
   58: 
   59: /*
   60:     State transitions between above modes -
   61: 
   62:     (most modes can go to BAD or MEM on error -- not shown for clarity)
   63: 
   64:     Process header:
   65:         HEAD -> (gzip) or (zlib) or (raw)
   66:         (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT ->
   67:                   HCRC -> TYPE
   68:         (zlib) -> DICTID or TYPE
   69:         DICTID -> DICT -> TYPE
   70:         (raw) -> TYPEDO
   71:     Read deflate blocks:
   72:             TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK
   73:             STORED -> COPY_ -> COPY -> TYPE
   74:             TABLE -> LENLENS -> CODELENS -> LEN_
   75:             LEN_ -> LEN
   76:     Read deflate codes in fixed or dynamic block:
   77:                 LEN -> LENEXT or LIT or TYPE
   78:                 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
   79:                 LIT -> LEN
   80:     Process trailer:
   81:         CHECK -> LENGTH -> DONE
   82:  */
   83: 
   84: /* state maintained between inflate() calls.  Approximately 10K bytes. */
   85: struct inflate_state {
   86:     inflate_mode mode;          /* current inflate mode */
   87:     int last;                   /* true if processing last block */
   88:     int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip */
   89:     int havedict;               /* true if dictionary provided */
   90:     int flags;                  /* gzip header method and flags (0 if zlib) */
   91:     unsigned dmax;              /* zlib header max distance (INFLATE_STRICT) */
   92:     unsigned long check;        /* protected copy of check value */
   93:     unsigned long total;        /* protected copy of output count */
   94:     gz_headerp head;            /* where to save gzip header information */
   95:         /* sliding window */
   96:     unsigned wbits;             /* log base 2 of requested window size */
   97:     unsigned wsize;             /* window size or zero if not using window */
   98:     unsigned whave;             /* valid bytes in the window */
   99:     unsigned wnext;             /* window write index */
  100:     unsigned char FAR *window;  /* allocated sliding window, if needed */
  101:         /* bit accumulator */
  102:     unsigned long hold;         /* input bit accumulator */
  103:     unsigned bits;              /* number of bits in "in" */
  104:         /* for string and stored block copying */
  105:     unsigned length;            /* literal or length of data to copy */
  106:     unsigned offset;            /* distance back to copy string from */
  107:         /* for table and code decoding */
  108:     unsigned extra;             /* extra bits needed */
  109:         /* fixed and dynamic code tables */
  110:     code const FAR *lencode;    /* starting table for length/literal codes */
  111:     code const FAR *distcode;   /* starting table for distance codes */
  112:     unsigned lenbits;           /* index bits for lencode */
  113:     unsigned distbits;          /* index bits for distcode */
  114:         /* dynamic table building */
  115:     unsigned ncode;             /* number of code length code lengths */
  116:     unsigned nlen;              /* number of length code lengths */
  117:     unsigned ndist;             /* number of distance code lengths */
  118:     unsigned have;              /* number of code lengths in lens[] */
  119:     code FAR *next;             /* next available space in codes[] */
  120:     unsigned short lens[320];   /* temporary storage for code lengths */
  121:     unsigned short work[288];   /* work area for code table building */
  122:     code codes[ENOUGH];         /* space for code tables */
  123:     int sane;                   /* if false, allow invalid distance too far */
  124:     int back;                   /* bits back of last unprocessed length/lit */
  125:     unsigned was;               /* initial length of match */
  126: };