[178] | 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 | }; |
---|