jediacademy/code/zlib32/inflate.h

146 lines
4.7 KiB
C
Raw Normal View History

2013-04-04 22:35:38 +00:00
// Maximum size of dynamic tree. The maximum found in a long but non-
// exhaustive search was 1004 huft structures (850 for length/literals
// and 154 for distances, the latter actually the result of an
// exhaustive search). The actual maximum is not known, but the
// value below is more than safe.
#define MANY 1440
// maximum bit length of any code (if BMAX needs to be larger than 16, then h and x[] should be ulong.)
#define BMAX 15
typedef ulong (*check_func) (ulong check, const byte *buf, ulong len);
typedef enum
{
TYPE, // get type bits (3, including end bit)
LENS, // get lengths for stored
STORED, // processing stored block
TABLE, // get table lengths
BTREE, // get bit lengths tree for a dynamic block
DTREE, // get length, distance trees for a dynamic block
CODES, // processing fixed or dynamic block
DRY, // output remaining window bytes
DONE, // finished last block, done
BAD // got a data error--stuck here
} inflate_block_mode;
// waiting for "i:"=input, "o:"=output, "x:"=nothing
typedef enum
{
START, // x: set up for LEN
LEN, // i: get length/literal/eob next
LENEXT, // i: getting length extra (have base)
DIST, // i: get distance next
DISTEXT, // i: getting distance extra
COPY, // o: copying bytes in window, waiting for space
LIT, // o: got literal, waiting for output space
WASH, // o: got eob, possibly still output waiting
END, // x: got eob and all data flushed
BADCODE // x: got error
} inflate_codes_mode;
typedef enum
{
imMETHOD, // waiting for method byte
imFLAG, // waiting for flag byte
imBLOCKS, // decompressing blocks
imCHECK4, // four check bytes to go
imCHECK3, // three check bytes to go
imCHECK2, // two check bytes to go
imCHECK1, // one check byte to go
imDONE, // finished check, done
imBAD // got an error--stay here
} inflate_mode;
typedef struct inflate_huft_s
{
byte Exop; // number of extra bits or operation
byte Bits; // number of bits in this code or subcode
ulong base; // literal, length base, distance base, or table offset
} inflate_huft_t;
// inflate codes private state
typedef struct inflate_codes_state_s
{
inflate_codes_mode mode; // current inflate_codes mode
// mode dependent information
ulong len;
union
{
struct
{
inflate_huft_t *tree; // pointer into tree
ulong need; // bits needed
} code; // if LEN or DIST, where in tree
ulong lit; // if LIT, literal
struct
{
ulong get; // bits to get for extra
ulong dist; // distance back to copy from
} copy; // if EXT or COPY, where and how much
}; // submode
// mode independent information
byte lbits; // ltree bits decoded per branch
byte dbits; // dtree bits decoder per branch
inflate_huft_t *ltree; // literal/length/eob tree
inflate_huft_t *dtree; // distance tree
} inflate_codes_state_t;
// inflate blocks semi-private state
typedef struct inflate_blocks_state_s
{
// mode
inflate_block_mode mode; // current inflate_block mode
// mode dependent information
union
{
ulong left; // if STORED, bytes left to copy
struct
{
ulong table; // table lengths (14 bits)
ulong index; // index into blens (or border)
ulong *blens; // bit lengths of codes
ulong bb; // bit length tree depth
inflate_huft_t *tb; // bit length decoding tree
} trees; // if DTREE, decoding info for trees
struct
{
inflate_codes_state_t *codes;
} decode; // if CODES, current state
}; // submode
bool last; // true if this block is the last block
// mode independent information
ulong bitk; // bits in bit buffer
ulong bitb; // bit buffer
inflate_huft_t *hufts; // single malloc for tree space
byte window[WINDOW_SIZE]; // sliding window
byte *end; // one byte after sliding window
byte *read; // window read pointer
byte *write; // window write pointer
ulong check; // check on output
} inflate_blocks_state_t;
// inflate private state
typedef struct inflate_state_s
{
inflate_mode mode; // current inflate mode
ulong method; // if FLAGS, method byte
// mode independent information
int nowrap; // flag for no wrapper
ulong wbits; // log2(window size) (8..15, defaults to 15)
inflate_blocks_state_t *blocks; // current inflate_blocks state
ulong adler;
ulong calcadler;
} inflate_state;
// end