src/zlib/inflate.h

/* inflate.h -- internal inflate state definition
 * Copyright (C) 1995-2003 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/* WARNING: this file should *not* be used by applications. It is
   part of the implementation of the compression library and is
   subject to change. Applications should only use zlib.h.
 */

/* define NO_GZIP when compiling if you want to disable gzip header and
   trailer decoding by inflate().  NO_GZIP would be used to avoid linking in
   the crc code when it is not needed.  For shared libraries, gzip decoding
   should be left enabled. */
#ifndef NO_GZIP
#  define GUNZIP
#endif

/* Possible inflate modes between inflate() calls */
typedef enum {
    HEAD,       /* i: waiting for magic header */
#ifdef GUNZIP
    FLAGS,      /* i: waiting for method and flags (gzip) */
    TIME,       /* i: waiting for modification time (gzip) */
    OS,         /* i: waiting for extra flags and operating system (gzip) */
    EXLEN,      /* i: waiting for extra length (gzip) */
    EXTRA,      /* i: waiting for extra bytes (gzip) */
    NAME,       /* i: waiting for end of file name (gzip) */
    COMMENT,    /* i: waiting for end of comment (gzip) */
    HCRC,       /* i: waiting for header crc (gzip) */
#endif
    DICTID,     /* i: waiting for dictionary check value */
    DICT,       /* waiting for inflateSetDictionary() call */
        TYPE,       /* i: waiting for type bits, including last-flag bit */
        TYPEDO,     /* i: same, but skip check to exit inflate on new block */
        STORED,     /* i: waiting for stored size (length and complement) */
        COPY,       /* i/o: waiting for input or output to copy stored block */
        TABLE,      /* i: waiting for dynamic block table lengths */
        LENLENS,    /* i: waiting for code length code lengths */
        CODELENS,   /* i: waiting for length/lit and distance code lengths */
            LEN,        /* i: waiting for length/lit code */
            LENEXT,     /* i: waiting for length extra bits */
            DIST,       /* i: waiting for distance code */
            DISTEXT,    /* i: waiting for distance extra bits */
            MATCH,      /* o: waiting for output space to copy string */
            LIT,        /* o: waiting for output space to write literal */
    CHECK,      /* i: waiting for 32-bit check value */
#ifdef GUNZIP
    LENGTH,     /* i: waiting for 32-bit length (gzip) */
#endif
    DONE,       /* finished check, done -- remain here until reset */
    BAD,        /* got a data error -- remain here until reset */
    MEM,        /* got an inflate() memory error -- remain here until reset */
    SYNC        /* looking for synchronization bytes to restart inflate() */
} inflate_mode;

/*
    State transitions between above modes -

    (most modes can go to the BAD or MEM mode -- not shown for clarity)

    Process header:
        HEAD -> (gzip) or (zlib)
        (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
        NAME -> COMMENT -> HCRC -> TYPE
        (zlib) -> DICTID or TYPE
        DICTID -> DICT -> TYPE
    Read deflate blocks:
            TYPE -> STORED or TABLE or LEN or CHECK
            STORED -> COPY -> TYPE
            TABLE -> LENLENS -> CODELENS -> LEN
    Read deflate codes:
                LEN -> LENEXT or LIT or TYPE
                LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
                LIT -> LEN
    Process trailer:
        CHECK -> LENGTH -> DONE
 */

/* state maintained between inflate() calls.  Approximately 7K bytes. */
struct inflate_state {
    inflate_mode mode;          /* current inflate mode */
    int last;                   /* true if processing last block */
    int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip */
    int havedict;               /* true if dictionary provided */
    int flags;                  /* gzip header method and flags (0 if zlib) */
    unsigned long check;        /* protected copy of check value */
    unsigned long total;        /* protected copy of output count */
        /* sliding window */
    unsigned wbits;             /* log base 2 of requested window size */
    unsigned wsize;             /* window size or zero if not using window */
    unsigned whave;             /* valid bytes in the window */
    unsigned write;             /* window write index */
    unsigned char FAR *window;  /* allocated sliding window, if needed */
        /* bit accumulator */
    unsigned long hold;         /* input bit accumulator */
    unsigned bits;              /* number of bits in "in" */
        /* for string and stored block copying */
    unsigned length;            /* literal or length of data to copy */
    unsigned offset;            /* distance back to copy string from */
        /* for table and code decoding */
    unsigned extra;             /* extra bits needed */
        /* fixed and dynamic code tables */
    code const FAR *lencode;    /* starting table for length/literal codes */
    code const FAR *distcode;   /* starting table for distance codes */
    unsigned lenbits;           /* index bits for lencode */
    unsigned distbits;          /* index bits for distcode */
        /* dynamic table building */
    unsigned ncode;             /* number of code length code lengths */
    unsigned nlen;              /* number of length code lengths */
    unsigned ndist;             /* number of distance code lengths */
    unsigned have;              /* number of code lengths in lens[] */
    code FAR *next;             /* next available space in codes[] */
    unsigned short lens[320];   /* temporary storage for code lengths */
    unsigned short work[288];   /* work area for code table building */
    code codes[ENOUGH];         /* space for code tables */
};
Commit	Line	Data
	1	/* inflate.h -- internal inflate state definition
	2	* Copyright (C) 1995-2003 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, /* i: waiting for magic header */
	22	#ifdef GUNZIP
	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	#endif
	32	DICTID, /* i: waiting for dictionary check value */
	33	DICT, /* waiting for inflateSetDictionary() call */
	34	TYPE, /* i: waiting for type bits, including last-flag bit */
	35	TYPEDO, /* i: same, but skip check to exit inflate on new block */
	36	STORED, /* i: waiting for stored size (length and complement) */
	37	COPY, /* i/o: waiting for input or output to copy stored block */
	38	TABLE, /* i: waiting for dynamic block table lengths */
	39	LENLENS, /* i: waiting for code length code lengths */
	40	CODELENS, /* i: waiting for length/lit and distance code lengths */
	41	LEN, /* i: waiting for length/lit 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	#ifdef GUNZIP
	49	LENGTH, /* i: waiting for 32-bit length (gzip) */
	50	#endif
	51	DONE, /* finished check, done -- remain here until reset */
	52	BAD, /* got a data error -- remain here until reset */
	53	MEM, /* got an inflate() memory error -- remain here until reset */
	54	SYNC /* looking for synchronization bytes to restart inflate() */
	55	} inflate_mode;
	56
	57	/*
	58	State transitions between above modes -
	59
	60	(most modes can go to the BAD or MEM mode -- not shown for clarity)
	61
	62	Process header:
	63	HEAD -> (gzip) or (zlib)
	64	(gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
	65	NAME -> COMMENT -> HCRC -> TYPE
	66	(zlib) -> DICTID or TYPE
	67	DICTID -> DICT -> TYPE
	68	Read deflate blocks:
	69	TYPE -> STORED or TABLE or LEN or CHECK
	70	STORED -> COPY -> TYPE
	71	TABLE -> LENLENS -> CODELENS -> LEN
	72	Read deflate codes:
	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. */
	81	struct inflate_state {
	82	inflate_mode mode; /* current inflate mode */
	83	int last; /* true if processing last block */
	84	int wrap; /* bit 0 true for zlib, bit 1 true for gzip */
	85	int havedict; /* true if dictionary provided */
	86	int flags; /* gzip header method and flags (0 if zlib) */
	87	unsigned long check; /* protected copy of check value */
	88	unsigned long total; /* protected copy of output count */
	89	/* sliding window */
	90	unsigned wbits; /* log base 2 of requested window size */
	91	unsigned wsize; /* window size or zero if not using window */
	92	unsigned whave; /* valid bytes in the window */
	93	unsigned write; /* window write index */
	94	unsigned char FAR window; / allocated sliding window, if needed */
	95	/* bit accumulator */
	96	unsigned long hold; /* input bit accumulator */
	97	unsigned bits; /* number of bits in "in" */
	98	/* for string and stored block copying */
	99	unsigned length; /* literal or length of data to copy */
	100	unsigned offset; /* distance back to copy string from */
	101	/* for table and code decoding */
	102	unsigned extra; /* extra bits needed */
	103	/* fixed and dynamic code tables */
	104	code const FAR lencode; / starting table for length/literal codes */
	105	code const FAR distcode; / starting table for distance codes */
	106	unsigned lenbits; /* index bits for lencode */
	107	unsigned distbits; /* index bits for distcode */
	108	/* dynamic table building */
	109	unsigned ncode; /* number of code length code lengths */
	110	unsigned nlen; /* number of length code lengths */
	111	unsigned ndist; /* number of distance code lengths */
	112	unsigned have; /* number of code lengths in lens[] */
	113	code FAR next; / next available space in codes[] */
	114	unsigned short lens[320]; /* temporary storage for code lengths */
	115	unsigned short work[288]; /* work area for code table building */
	116	code codes[ENOUGH]; /* space for code tables */
	117	};