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1#ifndef INFLATE_H2#define INFLATE_H3 4/* inflate.h -- internal inflate state definition5 * Copyright (C) 1995-2004 Mark Adler6 * For conditions of distribution and use, see copyright notice in zlib.h7 */8 9/* WARNING: this file should *not* be used by applications. It is10 part of the implementation of the compression library and is11 subject to change. Applications should only use zlib.h.12 */13 14#include "inftrees.h"15 16/* Possible inflate modes between inflate() calls */17typedef enum {18 HEAD, /* i: waiting for magic header */19 FLAGS, /* i: waiting for method and flags (gzip) */20 TIME, /* i: waiting for modification time (gzip) */21 OS, /* i: waiting for extra flags and operating system (gzip) */22 EXLEN, /* i: waiting for extra length (gzip) */23 EXTRA, /* i: waiting for extra bytes (gzip) */24 NAME, /* i: waiting for end of file name (gzip) */25 COMMENT, /* i: waiting for end of comment (gzip) */26 HCRC, /* i: waiting for header crc (gzip) */27 DICTID, /* i: waiting for dictionary check value */28 DICT, /* waiting for inflateSetDictionary() call */29 TYPE, /* i: waiting for type bits, including last-flag bit */30 TYPEDO, /* i: same, but skip check to exit inflate on new block */31 STORED, /* i: waiting for stored size (length and complement) */32 COPY, /* i/o: waiting for input or output to copy stored block */33 TABLE, /* i: waiting for dynamic block table lengths */34 LENLENS, /* i: waiting for code length code lengths */35 CODELENS, /* i: waiting for length/lit and distance code lengths */36 LEN, /* i: waiting for length/lit code */37 LENEXT, /* i: waiting for length extra bits */38 DIST, /* i: waiting for distance code */39 DISTEXT, /* i: waiting for distance extra bits */40 MATCH, /* o: waiting for output space to copy string */41 LIT, /* o: waiting for output space to write literal */42 CHECK, /* i: waiting for 32-bit check value */43 LENGTH, /* i: waiting for 32-bit length (gzip) */44 DONE, /* finished check, done -- remain here until reset */45 BAD, /* got a data error -- remain here until reset */46 MEM, /* got an inflate() memory error -- remain here until reset */47 SYNC /* looking for synchronization bytes to restart inflate() */48} inflate_mode;49 50/*51 State transitions between above modes -52 53 (most modes can go to the BAD or MEM mode -- not shown for clarity)54 55 Process header:56 HEAD -> (gzip) or (zlib)57 (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME58 NAME -> COMMENT -> HCRC -> TYPE59 (zlib) -> DICTID or TYPE60 DICTID -> DICT -> TYPE61 Read deflate blocks:62 TYPE -> STORED or TABLE or LEN or CHECK63 STORED -> COPY -> TYPE64 TABLE -> LENLENS -> CODELENS -> LEN65 Read deflate codes:66 LEN -> LENEXT or LIT or TYPE67 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN68 LIT -> LEN69 Process trailer:70 CHECK -> LENGTH -> DONE71 */72 73/* state maintained between inflate() calls. Approximately 7K bytes. */74struct inflate_state {75 inflate_mode mode; /* current inflate mode */76 int last; /* true if processing last block */77 int wrap; /* bit 0 true for zlib, bit 1 true for gzip */78 int havedict; /* true if dictionary provided */79 int flags; /* gzip header method and flags (0 if zlib) */80 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */81 unsigned long check; /* protected copy of check value */82 unsigned long total; /* protected copy of output count */83 /* gz_headerp head; */ /* where to save gzip header information */84 /* sliding window */85 unsigned wbits; /* log base 2 of requested window size */86 unsigned wsize; /* window size or zero if not using window */87 unsigned whave; /* valid bytes in the window */88 unsigned write; /* window write index */89 unsigned char *window; /* allocated sliding window, if needed */90 /* bit accumulator */91 unsigned long hold; /* input bit accumulator */92 unsigned bits; /* number of bits in "in" */93 /* for string and stored block copying */94 unsigned length; /* literal or length of data to copy */95 unsigned offset; /* distance back to copy string from */96 /* for table and code decoding */97 unsigned extra; /* extra bits needed */98 /* fixed and dynamic code tables */99 code const *lencode; /* starting table for length/literal codes */100 code const *distcode; /* starting table for distance codes */101 unsigned lenbits; /* index bits for lencode */102 unsigned distbits; /* index bits for distcode */103 /* dynamic table building */104 unsigned ncode; /* number of code length code lengths */105 unsigned nlen; /* number of length code lengths */106 unsigned ndist; /* number of distance code lengths */107 unsigned have; /* number of code lengths in lens[] */108 code *next; /* next available space in codes[] */109 unsigned short lens[320]; /* temporary storage for code lengths */110 unsigned short work[288]; /* work area for code table building */111 code codes[ENOUGH]; /* space for code tables */112};113 114/* Reverse the bytes in a 32-bit value */115#define REVERSE(q) \116 ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \117 (((q) & 0xff00) << 8) + (((q) & 0xff) << 24))118 119#endif120