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Member "dmd2/src/phobos/etc/c/zlib/inflate.h" (20 Nov 2020, 6618 Bytes) of package /linux/misc/dmd.2.094.2.linux.tar.xz:


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    1 /* inflate.h -- internal inflate state definition
    2  * Copyright (C) 1995-2016 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 /* Possible inflate modes between inflate() calls */
   20 typedef enum {
   21     HEAD = 16180,   /* i: waiting for magic header */
   22     FLAGS,      /* i: waiting for method and flags (gzip) */
   23     TIME,       /* i: waiting for modification time (gzip) */
   24     OS,         /* i: waiting for extra flags and operating system (gzip) */
   25     EXLEN,      /* i: waiting for extra length (gzip) */
   26     EXTRA,      /* i: waiting for extra bytes (gzip) */
   27     NAME,       /* i: waiting for end of file name (gzip) */
   28     COMMENT,    /* i: waiting for end of comment (gzip) */
   29     HCRC,       /* i: waiting for header crc (gzip) */
   30     DICTID,     /* i: waiting for dictionary check value */
   31     DICT,       /* waiting for inflateSetDictionary() call */
   32         TYPE,       /* i: waiting for type bits, including last-flag bit */
   33         TYPEDO,     /* i: same, but skip check to exit inflate on new block */
   34         STORED,     /* i: waiting for stored size (length and complement) */
   35         COPY_,      /* i/o: same as COPY below, but only first time in */
   36         COPY,       /* i/o: waiting for input or output to copy stored block */
   37         TABLE,      /* i: waiting for dynamic block table lengths */
   38         LENLENS,    /* i: waiting for code length code lengths */
   39         CODELENS,   /* i: waiting for length/lit and distance code lengths */
   40             LEN_,       /* i: same as LEN below, but only first time in */
   41             LEN,        /* i: waiting for length/lit/eob code */
   42             LENEXT,     /* i: waiting for length extra bits */
   43             DIST,       /* i: waiting for distance code */
   44             DISTEXT,    /* i: waiting for distance extra bits */
   45             MATCH,      /* o: waiting for output space to copy string */
   46             LIT,        /* o: waiting for output space to write literal */
   47     CHECK,      /* i: waiting for 32-bit check value */
   48     LENGTH,     /* i: waiting for 32-bit length (gzip) */
   49     DONE,       /* finished check, done -- remain here until reset */
   50     BAD,        /* got a data error -- remain here until reset */
   51     MEM,        /* got an inflate() memory error -- remain here until reset */
   52     SYNC        /* looking for synchronization bytes to restart inflate() */
   53 } inflate_mode;
   54 
   55 /*
   56     State transitions between above modes -
   57 
   58     (most modes can go to BAD or MEM on error -- not shown for clarity)
   59 
   60     Process header:
   61         HEAD -> (gzip) or (zlib) or (raw)
   62         (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT ->
   63                   HCRC -> TYPE
   64         (zlib) -> DICTID or TYPE
   65         DICTID -> DICT -> TYPE
   66         (raw) -> TYPEDO
   67     Read deflate blocks:
   68             TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK
   69             STORED -> COPY_ -> COPY -> TYPE
   70             TABLE -> LENLENS -> CODELENS -> LEN_
   71             LEN_ -> LEN
   72     Read deflate codes in fixed or dynamic block:
   73                 LEN -> LENEXT or LIT or TYPE
   74                 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
   75                 LIT -> LEN
   76     Process trailer:
   77         CHECK -> LENGTH -> DONE
   78  */
   79 
   80 /* State maintained between inflate() calls -- approximately 7K bytes, not
   81    including the allocated sliding window, which is up to 32K bytes. */
   82 struct inflate_state {
   83     z_streamp strm;             /* pointer back to this zlib stream */
   84     inflate_mode mode;          /* current inflate mode */
   85     int last;                   /* true if processing last block */
   86     int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip,
   87                                    bit 2 true to validate check value */
   88     int havedict;               /* true if dictionary provided */
   89     int flags;                  /* gzip header method and flags (0 if zlib) */
   90     unsigned dmax;              /* zlib header max distance (INFLATE_STRICT) */
   91     unsigned long check;        /* protected copy of check value */
   92     unsigned long total;        /* protected copy of output count */
   93     gz_headerp head;            /* where to save gzip header information */
   94         /* sliding window */
   95     unsigned wbits;             /* log base 2 of requested window size */
   96     unsigned wsize;             /* window size or zero if not using window */
   97     unsigned whave;             /* valid bytes in the window */
   98     unsigned wnext;             /* window write index */
   99     unsigned char FAR *window;  /* allocated sliding window, if needed */
  100         /* bit accumulator */
  101     unsigned long hold;         /* input bit accumulator */
  102     unsigned bits;              /* number of bits in "in" */
  103         /* for string and stored block copying */
  104     unsigned length;            /* literal or length of data to copy */
  105     unsigned offset;            /* distance back to copy string from */
  106         /* for table and code decoding */
  107     unsigned extra;             /* extra bits needed */
  108         /* fixed and dynamic code tables */
  109     code const FAR *lencode;    /* starting table for length/literal codes */
  110     code const FAR *distcode;   /* starting table for distance codes */
  111     unsigned lenbits;           /* index bits for lencode */
  112     unsigned distbits;          /* index bits for distcode */
  113         /* dynamic table building */
  114     unsigned ncode;             /* number of code length code lengths */
  115     unsigned nlen;              /* number of length code lengths */
  116     unsigned ndist;             /* number of distance code lengths */
  117     unsigned have;              /* number of code lengths in lens[] */
  118     code FAR *next;             /* next available space in codes[] */
  119     unsigned short lens[320];   /* temporary storage for code lengths */
  120     unsigned short work[288];   /* work area for code table building */
  121     code codes[ENOUGH];         /* space for code tables */
  122     int sane;                   /* if false, allow invalid distance too far */
  123     int back;                   /* bits back of last unprocessed length/lit */
  124     unsigned was;               /* initial length of match */
  125 };