1131377Stjr/* inflate.h -- internal inflate state definition 2313796Sdelphij * Copyright (C) 1995-2016 Mark Adler 3131377Stjr * For conditions of distribution and use, see copyright notice in zlib.h 4131377Stjr */ 5131377Stjr 6131377Stjr/* WARNING: this file should *not* be used by applications. It is 7131377Stjr part of the implementation of the compression library and is 8131377Stjr subject to change. Applications should only use zlib.h. 9131377Stjr */ 10131377Stjr 11131377Stjr/* define NO_GZIP when compiling if you want to disable gzip header and 12131377Stjr trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 13131377Stjr the crc code when it is not needed. For shared libraries, gzip decoding 14131377Stjr should be left enabled. */ 15131377Stjr#ifndef NO_GZIP 16131377Stjr# define GUNZIP 17131377Stjr#endif 18131377Stjr 19131377Stjr/* Possible inflate modes between inflate() calls */ 20131377Stjrtypedef enum { 21313796Sdelphij HEAD = 16180, /* i: waiting for magic header */ 22131377Stjr FLAGS, /* i: waiting for method and flags (gzip) */ 23131377Stjr TIME, /* i: waiting for modification time (gzip) */ 24131377Stjr OS, /* i: waiting for extra flags and operating system (gzip) */ 25131377Stjr EXLEN, /* i: waiting for extra length (gzip) */ 26131377Stjr EXTRA, /* i: waiting for extra bytes (gzip) */ 27131377Stjr NAME, /* i: waiting for end of file name (gzip) */ 28131377Stjr COMMENT, /* i: waiting for end of comment (gzip) */ 29131377Stjr HCRC, /* i: waiting for header crc (gzip) */ 30131377Stjr DICTID, /* i: waiting for dictionary check value */ 31131377Stjr DICT, /* waiting for inflateSetDictionary() call */ 32131377Stjr TYPE, /* i: waiting for type bits, including last-flag bit */ 33131377Stjr TYPEDO, /* i: same, but skip check to exit inflate on new block */ 34131377Stjr STORED, /* i: waiting for stored size (length and complement) */ 35205194Sdelphij COPY_, /* i/o: same as COPY below, but only first time in */ 36131377Stjr COPY, /* i/o: waiting for input or output to copy stored block */ 37131377Stjr TABLE, /* i: waiting for dynamic block table lengths */ 38131377Stjr LENLENS, /* i: waiting for code length code lengths */ 39131377Stjr CODELENS, /* i: waiting for length/lit and distance code lengths */ 40205194Sdelphij LEN_, /* i: same as LEN below, but only first time in */ 41205194Sdelphij LEN, /* i: waiting for length/lit/eob code */ 42131377Stjr LENEXT, /* i: waiting for length extra bits */ 43131377Stjr DIST, /* i: waiting for distance code */ 44131377Stjr DISTEXT, /* i: waiting for distance extra bits */ 45131377Stjr MATCH, /* o: waiting for output space to copy string */ 46131377Stjr LIT, /* o: waiting for output space to write literal */ 47131377Stjr CHECK, /* i: waiting for 32-bit check value */ 48131377Stjr LENGTH, /* i: waiting for 32-bit length (gzip) */ 49131377Stjr DONE, /* finished check, done -- remain here until reset */ 50131377Stjr BAD, /* got a data error -- remain here until reset */ 51131377Stjr MEM, /* got an inflate() memory error -- remain here until reset */ 52131377Stjr SYNC /* looking for synchronization bytes to restart inflate() */ 53131377Stjr} inflate_mode; 54131377Stjr 55131377Stjr/* 56131377Stjr State transitions between above modes - 57131377Stjr 58205194Sdelphij (most modes can go to BAD or MEM on error -- not shown for clarity) 59131377Stjr 60131377Stjr Process header: 61205194Sdelphij HEAD -> (gzip) or (zlib) or (raw) 62205194Sdelphij (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> 63205194Sdelphij HCRC -> TYPE 64131377Stjr (zlib) -> DICTID or TYPE 65131377Stjr DICTID -> DICT -> TYPE 66205194Sdelphij (raw) -> TYPEDO 67131377Stjr Read deflate blocks: 68205194Sdelphij TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK 69205194Sdelphij STORED -> COPY_ -> COPY -> TYPE 70205194Sdelphij TABLE -> LENLENS -> CODELENS -> LEN_ 71205194Sdelphij LEN_ -> LEN 72205194Sdelphij Read deflate codes in fixed or dynamic block: 73131377Stjr LEN -> LENEXT or LIT or TYPE 74131377Stjr LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 75131377Stjr LIT -> LEN 76131377Stjr Process trailer: 77131377Stjr CHECK -> LENGTH -> DONE 78131377Stjr */ 79131377Stjr 80313796Sdelphij/* State maintained between inflate() calls -- approximately 7K bytes, not 81313796Sdelphij including the allocated sliding window, which is up to 32K bytes. */ 82131377Stjrstruct inflate_state { 83313796Sdelphij z_streamp strm; /* pointer back to this zlib stream */ 84131377Stjr inflate_mode mode; /* current inflate mode */ 85131377Stjr int last; /* true if processing last block */ 86313796Sdelphij int wrap; /* bit 0 true for zlib, bit 1 true for gzip, 87313796Sdelphij bit 2 true to validate check value */ 88131377Stjr int havedict; /* true if dictionary provided */ 89131377Stjr int flags; /* gzip header method and flags (0 if zlib) */ 90157043Sdes unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 91131377Stjr unsigned long check; /* protected copy of check value */ 92131377Stjr unsigned long total; /* protected copy of output count */ 93157043Sdes gz_headerp head; /* where to save gzip header information */ 94131377Stjr /* sliding window */ 95131377Stjr unsigned wbits; /* log base 2 of requested window size */ 96131377Stjr unsigned wsize; /* window size or zero if not using window */ 97131377Stjr unsigned whave; /* valid bytes in the window */ 98205194Sdelphij unsigned wnext; /* window write index */ 99131377Stjr unsigned char FAR *window; /* allocated sliding window, if needed */ 100131377Stjr /* bit accumulator */ 101131377Stjr unsigned long hold; /* input bit accumulator */ 102131377Stjr unsigned bits; /* number of bits in "in" */ 103131377Stjr /* for string and stored block copying */ 104131377Stjr unsigned length; /* literal or length of data to copy */ 105131377Stjr unsigned offset; /* distance back to copy string from */ 106131377Stjr /* for table and code decoding */ 107131377Stjr unsigned extra; /* extra bits needed */ 108131377Stjr /* fixed and dynamic code tables */ 109131377Stjr code const FAR *lencode; /* starting table for length/literal codes */ 110131377Stjr code const FAR *distcode; /* starting table for distance codes */ 111131377Stjr unsigned lenbits; /* index bits for lencode */ 112131377Stjr unsigned distbits; /* index bits for distcode */ 113131377Stjr /* dynamic table building */ 114131377Stjr unsigned ncode; /* number of code length code lengths */ 115131377Stjr unsigned nlen; /* number of length code lengths */ 116131377Stjr unsigned ndist; /* number of distance code lengths */ 117131377Stjr unsigned have; /* number of code lengths in lens[] */ 118131377Stjr code FAR *next; /* next available space in codes[] */ 119131377Stjr unsigned short lens[320]; /* temporary storage for code lengths */ 120131377Stjr unsigned short work[288]; /* work area for code table building */ 121131377Stjr code codes[ENOUGH]; /* space for code tables */ 122205194Sdelphij int sane; /* if false, allow invalid distance too far */ 123205194Sdelphij int back; /* bits back of last unprocessed length/lit */ 124205194Sdelphij unsigned was; /* initial length of match */ 125131377Stjr}; 126