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Annotation of embedaddon/rsync/zlib/inflate.h, revision 1.1.1.2

1.1       misho       1: /* inflate.h -- internal inflate state definition
1.1.1.2 ! misho       2:  * Copyright (C) 1995-2009 Mark Adler
1.1       misho       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) */
1.1.1.2 ! misho      39:         COPY_,      /* i/o: same as COPY below, but only first time in */
1.1       misho      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 */
1.1.1.2 ! misho      44:             LEN_,       /* i: same as LEN below, but only first time in */
        !            45:             LEN,        /* i: waiting for length/lit/eob code */
1.1       misho      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: 
1.1.1.2 ! misho      62:     (most modes can go to BAD or MEM on error -- not shown for clarity)
1.1       misho      63: 
                     64:     Process header:
1.1.1.2 ! misho      65:         HEAD -> (gzip) or (zlib) or (raw)
        !            66:         (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT ->
        !            67:                   HCRC -> TYPE
1.1       misho      68:         (zlib) -> DICTID or TYPE
                     69:         DICTID -> DICT -> TYPE
1.1.1.2 ! misho      70:         (raw) -> TYPEDO
1.1       misho      71:     Read deflate blocks:
1.1.1.2 ! misho      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:
1.1       misho      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: 
1.1.1.2 ! misho      84: /* state maintained between inflate() calls.  Approximately 10K bytes. */
1.1       misho      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 */
1.1.1.2 ! misho      99:     unsigned wnext;             /* window write index */
1.1       misho     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 */
1.1.1.2 ! misho     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 */
1.1       misho     126: };