apps/plugins/png/inflate.h

   1 /* inflate.h -- internal inflate state definition
   2  * Copyright (C) 1995-2004 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
  16 #ifndef NO_GZIP
  17 #  define GUNZIP
  18 #endif
  19
  20 /* Possible inflate modes between inflate() calls */
  21 typedef enum {
  22     HEAD,       /* i: waiting for magic header */
  23     FLAGS,      /* i: waiting for method and flags (gzip) */
  24     TIME,       /* i: waiting for modification time (gzip) */
  25     OS,         /* i: waiting for extra flags and operating system (gzip) */
  26     EXLEN,      /* i: waiting for extra length (gzip) */
  27     EXTRA,      /* i: waiting for extra bytes (gzip) */
  28     NAME,       /* i: waiting for end of file name (gzip) */
  29     COMMENT,    /* i: waiting for end of comment (gzip) */
  30     HCRC,       /* i: waiting for header crc (gzip) */
  31     DICTID,     /* i: waiting for dictionary check value */
  32     DICT,       /* waiting for inflateSetDictionary() call */
  33         TYPE,       /* i: waiting for type bits, including last-flag bit */
  34         TYPEDO,     /* i: same, but skip check to exit inflate on new block */
  35         STORED,     /* i: waiting for stored size (length and complement) */
  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: waiting for length/lit code */
  41             LENEXT,     /* i: waiting for length extra bits */
  42             DIST,       /* i: waiting for distance code */
  43             DISTEXT,    /* i: waiting for distance extra bits */
  44             MATCH,      /* o: waiting for output space to copy string */
  45             LIT,        /* o: waiting for output space to write literal */
  46     CHECK,      /* i: waiting for 32-bit check value */
  47     LENGTH,     /* i: waiting for 32-bit length (gzip) */
  48     DONE,       /* finished check, done -- remain here until reset */
  49     BAD,        /* got a data error -- remain here until reset */
  50     ZMEM,        /* got an inflate() memory error -- remain here until reset */
  51     SYNC        /* looking for synchronization bytes to restart inflate() */
  52 } inflate_mode;
  53
  54 /*
  55     State transitions between above modes -
  56
  57     (most modes can go to the BAD or MEM mode -- not shown for clarity)
  58
  59     Process header:
  60         HEAD -> (gzip) or (zlib)
  61         (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
  62         NAME -> COMMENT -> HCRC -> TYPE
  63         (zlib) -> DICTID or TYPE
  64         DICTID -> DICT -> TYPE
  65     Read deflate blocks:
  66             TYPE -> STORED or TABLE or LEN or CHECK
  67             STORED -> COPY -> TYPE
  68             TABLE -> LENLENS -> CODELENS -> LEN
  69     Read deflate codes:
  70                 LEN -> LENEXT or LIT or TYPE
  71                 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
  72                 LIT -> LEN
  73     Process trailer:
  74         CHECK -> LENGTH -> DONE
  75  */
  76
  77 /* state maintained between inflate() calls.  Approximately 7K bytes. */
  78 struct inflate_state {
  79     inflate_mode mode;          /* current inflate mode */
  80     int last;                   /* true if processing last block */
  81     int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip */
  82     int havedict;               /* true if dictionary provided */
  83     int flags;                  /* gzip header method and flags (0 if zlib) */
  84     unsigned dmax;              /* zlib header max distance (INFLATE_STRICT) */
  85     unsigned long check;        /* protected copy of check value */
  86     unsigned long total;        /* protected copy of output count */
  87     gz_headerp head;            /* where to save gzip header information */
  88         /* sliding window */
  89     unsigned wbits;             /* log base 2 of requested window size */
  90     unsigned wsize;             /* window size or zero if not using window */
  91     unsigned whave;             /* valid bytes in the window */
  92     unsigned write;             /* window write index */
  93     unsigned char FAR *window;  /* allocated sliding window, if needed */
  94         /* bit accumulator */
  95     unsigned long hold;         /* input bit accumulator */
  96     unsigned bits;              /* number of bits in "in" */
  97         /* for string and stored block copying */
  98     unsigned length;            /* literal or length of data to copy */
  99     unsigned offset;            /* distance back to copy string from */
 100         /* for table and code decoding */
 101     unsigned extra;             /* extra bits needed */
 102         /* fixed and dynamic code tables */
 103     code const FAR *lencode;    /* starting table for length/literal codes */
 104     code const FAR *distcode;   /* starting table for distance codes */
 105     unsigned lenbits;           /* index bits for lencode */
 106     unsigned distbits;          /* index bits for distcode */
 107         /* dynamic table building */
 108     unsigned ncode;             /* number of code length code lengths */
 109     unsigned nlen;              /* number of length code lengths */
 110     unsigned ndist;             /* number of distance code lengths */
 111     unsigned have;              /* number of code lengths in lens[] */
 112     code FAR *next;             /* next available space in codes[] */
 113     unsigned short lens[320];   /* temporary storage for code lengths */
 114     unsigned short work[288];   /* work area for code table building */
 115     code codes[ENOUGH];         /* space for code tables */
 116 };