00001 /* inflate.h -- internal inflate state definition 00002 * Copyright (C) 1995-2004 Mark Adler 00003 * For conditions of distribution and use, see copyright notice in zlib.h 00004 */ 00005 00006 /* WARNING: this file should *not* be used by applications. It is 00007 part of the implementation of the compression library and is 00008 subject to change. Applications should only use zlib.h. 00009 */ 00010 00011 /* define NO_GZIP when compiling if you want to disable gzip header and 00012 trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 00013 the crc code when it is not needed. For shared libraries, gzip decoding 00014 should be left enabled. */ 00015 #ifndef NO_GZIP 00016 # define GUNZIP 00017 #endif 00018 00019 /* Possible inflate modes between inflate() calls */ 00020 typedef enum { 00021 HEAD, /* i: waiting for magic header */ 00022 FLAGS, /* i: waiting for method and flags (gzip) */ 00023 TIME, /* i: waiting for modification time (gzip) */ 00024 OS, /* i: waiting for extra flags and operating system (gzip) */ 00025 EXLEN, /* i: waiting for extra length (gzip) */ 00026 EXTRA, /* i: waiting for extra bytes (gzip) */ 00027 NAME, /* i: waiting for end of file name (gzip) */ 00028 COMMENT, /* i: waiting for end of comment (gzip) */ 00029 HCRC, /* i: waiting for header crc (gzip) */ 00030 DICTID, /* i: waiting for dictionary check value */ 00031 DICT, /* waiting for inflateSetDictionary() call */ 00032 TYPE, /* i: waiting for type bits, including last-flag bit */ 00033 TYPEDO, /* i: same, but skip check to exit inflate on new block */ 00034 STORED, /* i: waiting for stored size (length and complement) */ 00035 COPY, /* i/o: waiting for input or output to copy stored block */ 00036 TABLE, /* i: waiting for dynamic block table lengths */ 00037 LENLENS, /* i: waiting for code length code lengths */ 00038 CODELENS, /* i: waiting for length/lit and distance code lengths */ 00039 LEN, /* i: waiting for length/lit code */ 00040 LENEXT, /* i: waiting for length extra bits */ 00041 DIST, /* i: waiting for distance code */ 00042 DISTEXT, /* i: waiting for distance extra bits */ 00043 MATCH, /* o: waiting for output space to copy string */ 00044 LIT, /* o: waiting for output space to write literal */ 00045 CHECK, /* i: waiting for 32-bit check value */ 00046 LENGTH, /* i: waiting for 32-bit length (gzip) */ 00047 DONE, /* finished check, done -- remain here until reset */ 00048 BAD, /* got a data error -- remain here until reset */ 00049 MEM, /* got an inflate() memory error -- remain here until reset */ 00050 SYNC /* looking for synchronization bytes to restart inflate() */ 00051 } inflate_mode; 00052 00053 /* 00054 State transitions between above modes - 00055 00056 (most modes can go to the BAD or MEM mode -- not shown for clarity) 00057 00058 Process header: 00059 HEAD -> (gzip) or (zlib) 00060 (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME 00061 NAME -> COMMENT -> HCRC -> TYPE 00062 (zlib) -> DICTID or TYPE 00063 DICTID -> DICT -> TYPE 00064 Read deflate blocks: 00065 TYPE -> STORED or TABLE or LEN or CHECK 00066 STORED -> COPY -> TYPE 00067 TABLE -> LENLENS -> CODELENS -> LEN 00068 Read deflate codes: 00069 LEN -> LENEXT or LIT or TYPE 00070 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 00071 LIT -> LEN 00072 Process trailer: 00073 CHECK -> LENGTH -> DONE 00074 */ 00075 00076 /* state maintained between inflate() calls. Approximately 7K bytes. */ 00077 struct inflate_state { 00078 inflate_mode mode; /* current inflate mode */ 00079 int last; /* true if processing last block */ 00080 int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ 00081 int havedict; /* true if dictionary provided */ 00082 int flags; /* gzip header method and flags (0 if zlib) */ 00083 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 00084 unsigned long check; /* protected copy of check value */ 00085 unsigned long total; /* protected copy of output count */ 00086 gz_headerp head; /* where to save gzip header information */ 00087 /* sliding window */ 00088 unsigned wbits; /* log base 2 of requested window size */ 00089 unsigned wsize; /* window size or zero if not using window */ 00090 unsigned whave; /* valid bytes in the window */ 00091 unsigned write; /* window write index */ 00092 unsigned char FAR *window; /* allocated sliding window, if needed */ 00093 /* bit accumulator */ 00094 unsigned long hold; /* input bit accumulator */ 00095 unsigned bits; /* number of bits in "in" */ 00096 /* for string and stored block copying */ 00097 unsigned length; /* literal or length of data to copy */ 00098 unsigned offset; /* distance back to copy string from */ 00099 /* for table and code decoding */ 00100 unsigned extra; /* extra bits needed */ 00101 /* fixed and dynamic code tables */ 00102 code const FAR *lencode; /* starting table for length/literal codes */ 00103 code const FAR *distcode; /* starting table for distance codes */ 00104 unsigned lenbits; /* index bits for lencode */ 00105 unsigned distbits; /* index bits for distcode */ 00106 /* dynamic table building */ 00107 unsigned ncode; /* number of code length code lengths */ 00108 unsigned nlen; /* number of length code lengths */ 00109 unsigned ndist; /* number of distance code lengths */ 00110 unsigned have; /* number of code lengths in lens[] */ 00111 code FAR *next; /* next available space in codes[] */ 00112 unsigned short lens[320]; /* temporary storage for code lengths */ 00113 unsigned short work[288]; /* work area for code table building */ 00114 code codes[ENOUGH]; /* space for code tables */ 00115 };