deflate.h File Reference

Internal compression state. More...

#include "zutil.h"

Go to the source code of this file.

Data Structures
struct	ct_data
	Data structure describing a single value and its code string. More...
struct	tree_desc
struct	deflate_state
	Deflate internal state. More...

Macros
#define	GZIP
#define	LENGTH_CODES   29
#define	LITERALS   256
#define	L_CODES   (LITERALS+1+LENGTH_CODES)
#define	D_CODES   30
#define	BL_CODES   19
#define	HEAP_SIZE   (2*L_CODES+1)
#define	MAX_BITS   15
#define	Buf_size   16
#define	INIT_STATE   42 /* zlib header -> BUSY_STATE */
#define	GZIP_STATE   57 /* gzip header -> BUSY_STATE | EXTRA_STATE */
#define	EXTRA_STATE   69 /* gzip extra block -> NAME_STATE */
#define	NAME_STATE   73 /* gzip file name -> COMMENT_STATE */
#define	COMMENT_STATE   91 /* gzip comment -> HCRC_STATE */
#define	HCRC_STATE   103 /* gzip header CRC -> BUSY_STATE */
#define	BUSY_STATE   113 /* deflate -> FINISH_STATE */
#define	FINISH_STATE   666 /* stream complete */
#define	Freq   fc.freq
#define	Code   fc.code
#define	Dad   dl.dad
#define	Len   dl.len
#define	put_byte(s, c)   {s->pending_buf[s->pending++] = (Bytef)(c);}
#define	MIN_LOOKAHEAD   (MAX_MATCH+MIN_MATCH+1)
#define	MAX_DIST(s)   ((s)->w_size-MIN_LOOKAHEAD)
#define	WIN_INIT   MAX_MATCH
#define	d_code(dist)    ((dist) < 256 ? _dist_code[dist] : _dist_code[256+((dist)>>7)])
#define	_tr_tally_lit(s, c, flush)
#define	_tr_tally_dist(s, distance, length, flush)
used by deflate.c:
#define	max_insert_length   max_lazy_match
	Insert new strings in the hash table only if the match length is not greater than this length.

Typedefs
typedef ush	Pos
typedef Pos FAR	Posf
typedef unsigned	IPos

Functions
void ZLIB_INTERNAL	_tr_init (deflate_state *s)
int ZLIB_INTERNAL	_tr_tally (deflate_state *s, unsigned dist, unsigned lc)
void ZLIB_INTERNAL	_tr_flush_block (deflate_state *s, charf *buf, ulg stored_len, int last)
void ZLIB_INTERNAL	_tr_flush_bits (deflate_state *s)
void ZLIB_INTERNAL	_tr_align (deflate_state *s)
void ZLIB_INTERNAL	_tr_stored_block (deflate_state *s, charf *buf, ulg stored_len, int last)

Variables
uch ZLIB_INTERNAL	_length_code []
uch ZLIB_INTERNAL	_dist_code []

Detailed Description

Internal compression state.

Copyright (C) 1995-2018 Jean-loup Gailly For conditions of distribution and use, see copyright notice in zlib.h

Warning

This file should not be used by applications. It is part of the implementation of the compression library and is subject to change. Applications should only use zlib.h.

Macro Definition Documentation

_tr_tally_dist

#define _tr_tally_dist	(		s,
			distance,
			length,
			flush
	)

Value:

  { uch len = (uch)(length); \
    ush dist = (ush)(distance); \
    s->sym_buf[s->sym_next++] = (uch)dist; \
    s->sym_buf[s->sym_next++] = (uch)(dist >> 8); \
    s->sym_buf[s->sym_next++] = len; \
    dist--; \
    s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
    s->dyn_dtree[d_code(dist)].Freq++; \
    flush = (s->sym_next == s->sym_end); \
  }

_tr_tally_lit

#define _tr_tally_lit	(		s,
			c,
			flush
	)

Value:

  { uch cc = (c); \
    s->sym_buf[s->sym_next++] = 0; \
    s->sym_buf[s->sym_next++] = 0; \
    s->sym_buf[s->sym_next++] = cc; \
    s->dyn_ltree[cc].Freq++; \
    flush = (s->sym_next == s->sym_end); \
   }

max_insert_length

#define max_insert_length   max_lazy_match

Insert new strings in the hash table only if the match length is not greater than this length.

This saves time but degrades compression. max_insert_length is used only for compression levels <= 3.