linux/lib/zlib_inflate/inflate.h
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   1#ifndef INFLATE_H
   2#define INFLATE_H
   3
   4/* inflate.h -- internal inflate state definition
   5 * Copyright (C) 1995-2004 Mark Adler
   6 * For conditions of distribution and use, see copyright notice in zlib.h
   7 */
   8
   9/* WARNING: this file should *not* be used by applications. It is
  10   part of the implementation of the compression library and is
  11   subject to change. Applications should only use zlib.h.
  12 */
  13
  14/* Possible inflate modes between inflate() calls */
  15typedef enum {
  16    HEAD,       /* i: waiting for magic header */
  17    FLAGS,      /* i: waiting for method and flags (gzip) */
  18    TIME,       /* i: waiting for modification time (gzip) */
  19    OS,         /* i: waiting for extra flags and operating system (gzip) */
  20    EXLEN,      /* i: waiting for extra length (gzip) */
  21    EXTRA,      /* i: waiting for extra bytes (gzip) */
  22    NAME,       /* i: waiting for end of file name (gzip) */
  23    COMMENT,    /* i: waiting for end of comment (gzip) */
  24    HCRC,       /* i: waiting for header crc (gzip) */
  25    DICTID,     /* i: waiting for dictionary check value */
  26    DICT,       /* waiting for inflateSetDictionary() call */
  27        TYPE,       /* i: waiting for type bits, including last-flag bit */
  28        TYPEDO,     /* i: same, but skip check to exit inflate on new block */
  29        STORED,     /* i: waiting for stored size (length and complement) */
  30        COPY,       /* i/o: waiting for input or output to copy stored block */
  31        TABLE,      /* i: waiting for dynamic block table lengths */
  32        LENLENS,    /* i: waiting for code length code lengths */
  33        CODELENS,   /* i: waiting for length/lit and distance code lengths */
  34            LEN,        /* i: waiting for length/lit code */
  35            LENEXT,     /* i: waiting for length extra bits */
  36            DIST,       /* i: waiting for distance code */
  37            DISTEXT,    /* i: waiting for distance extra bits */
  38            MATCH,      /* o: waiting for output space to copy string */
  39            LIT,        /* o: waiting for output space to write literal */
  40    CHECK,      /* i: waiting for 32-bit check value */
  41    LENGTH,     /* i: waiting for 32-bit length (gzip) */
  42    DONE,       /* finished check, done -- remain here until reset */
  43    BAD,        /* got a data error -- remain here until reset */
  44    MEM,        /* got an inflate() memory error -- remain here until reset */
  45    SYNC        /* looking for synchronization bytes to restart inflate() */
  46} inflate_mode;
  47
  48/*
  49    State transitions between above modes -
  50
  51    (most modes can go to the BAD or MEM mode -- not shown for clarity)
  52
  53    Process header:
  54        HEAD -> (gzip) or (zlib)
  55        (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
  56        NAME -> COMMENT -> HCRC -> TYPE
  57        (zlib) -> DICTID or TYPE
  58        DICTID -> DICT -> TYPE
  59    Read deflate blocks:
  60            TYPE -> STORED or TABLE or LEN or CHECK
  61            STORED -> COPY -> TYPE
  62            TABLE -> LENLENS -> CODELENS -> LEN
  63    Read deflate codes:
  64                LEN -> LENEXT or LIT or TYPE
  65                LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
  66                LIT -> LEN
  67    Process trailer:
  68        CHECK -> LENGTH -> DONE
  69 */
  70
  71/* state maintained between inflate() calls.  Approximately 7K bytes. */
  72struct inflate_state {
  73    inflate_mode mode;          /* current inflate mode */
  74    int last;                   /* true if processing last block */
  75    int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip */
  76    int havedict;               /* true if dictionary provided */
  77    int flags;                  /* gzip header method and flags (0 if zlib) */
  78    unsigned dmax;              /* zlib header max distance (INFLATE_STRICT) */
  79    unsigned long check;        /* protected copy of check value */
  80    unsigned long total;        /* protected copy of output count */
  81 /*   gz_headerp head; */           /* where to save gzip header information */
  82        /* sliding window */
  83    unsigned wbits;             /* log base 2 of requested window size */
  84    unsigned wsize;             /* window size or zero if not using window */
  85    unsigned whave;             /* valid bytes in the window */
  86    unsigned write;             /* window write index */
  87    unsigned char *window;  /* allocated sliding window, if needed */
  88        /* bit accumulator */
  89    unsigned long hold;         /* input bit accumulator */
  90    unsigned bits;              /* number of bits in "in" */
  91        /* for string and stored block copying */
  92    unsigned length;            /* literal or length of data to copy */
  93    unsigned offset;            /* distance back to copy string from */
  94        /* for table and code decoding */
  95    unsigned extra;             /* extra bits needed */
  96        /* fixed and dynamic code tables */
  97    code const *lencode;    /* starting table for length/literal codes */
  98    code const *distcode;   /* starting table for distance codes */
  99    unsigned lenbits;           /* index bits for lencode */
 100    unsigned distbits;          /* index bits for distcode */
 101        /* dynamic table building */
 102    unsigned ncode;             /* number of code length code lengths */
 103    unsigned nlen;              /* number of length code lengths */
 104    unsigned ndist;             /* number of distance code lengths */
 105    unsigned have;              /* number of code lengths in lens[] */
 106    code *next;             /* next available space in codes[] */
 107    unsigned short lens[320];   /* temporary storage for code lengths */
 108    unsigned short work[288];   /* work area for code table building */
 109    code codes[ENOUGH];         /* space for code tables */
 110};
 111#endif
 112
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