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- /* deflate.h -- internal compression state
- * Copyright (C) 1995-1998 Jean-loup Gailly
- * For conditions of distribution and use, see copyright notice in zlib.h
- */
-
-
- #ifndef _DEFLATE_H
- #define _DEFLATE_H
-
- #include "zutil.h"
-
- /* ===========================================================================
- * Internal compression state.
- */
-
- #define LENGTH_CODES 29
- /* number of length codes, not counting the special END_BLOCK code */
-
- #define LITERALS 256
- /* number of literal bytes 0..255 */
-
- #define L_CODES (LITERALS+1+LENGTH_CODES)
- /* number of Literal or Length codes, including the END_BLOCK code */
-
- #define D_CODES 30
- /* number of distance codes */
-
- #define BL_CODES 19
- /* number of codes used to transfer the bit lengths */
-
- #define HEAP_SIZE (2*L_CODES+1)
- /* maximum heap size */
-
- #define MAX_BITS 15
- /* All codes must not exceed MAX_BITS bits */
-
- #define INIT_STATE 42
- #define BUSY_STATE 113
- #define FINISH_STATE 666
- /* Stream status */
-
-
- /* Data structure describing a single value and its code string. */
- typedef struct ct_data_s {
- union {
- ush freq; /* frequency count */
- ush code; /* bit string */
- } fc;
- union {
- ush dad; /* father node in Huffman tree */
- ush len; /* length of bit string */
- } dl;
- } FAR ct_data;
-
- #define Freq fc.freq
- #define Code fc.code
- #define Dad dl.dad
- #define Len dl.len
-
- typedef struct static_tree_desc_s static_tree_desc;
-
- typedef struct tree_desc_s {
- ct_data *dyn_tree; /* the dynamic tree */
- int max_code; /* largest code with non zero frequency */
- static_tree_desc *stat_desc; /* the corresponding static tree */
- } FAR tree_desc;
-
- typedef ush Pos;
- typedef Pos FAR Posf;
- typedef unsigned IPos;
-
- /* A Pos is an index in the character window. We use short instead of int to
- * save space in the various tables. IPos is used only for parameter passing.
- */
-
- typedef struct internal_state {
- z_streamp strm; /* pointer back to this zlib stream */
- int status; /* as the name implies */
- Bytef *pending_buf; /* output still pending */
- ulg pending_buf_size; /* size of pending_buf */
- Bytef *pending_out; /* next pending byte to output to the stream */
- int pending; /* nb of bytes in the pending buffer */
- int noheader; /* suppress zlib header and adler32 */
- Byte method; /* STORED (for zip only) or DEFLATED */
- int last_flush; /* value of flush param for previous deflate call */
-
- /* used by deflate.c: */
-
- uInt w_size; /* LZ77 window size (32K by default) */
- uInt w_bits; /* log2(w_size) (8..16) */
- uInt w_mask; /* w_size - 1 */
-
- Bytef *window;
-
- ulg window_size;
-
- Posf *prev;
-
- Posf *head; /* Heads of the hash chains or NIL. */
-
- uInt ins_h; /* hash index of string to be inserted */
- uInt hash_size; /* number of elements in hash table */
- uInt hash_bits; /* log2(hash_size) */
- uInt hash_mask; /* hash_size-1 */
-
- uInt hash_shift;
- long block_start;
-
- uInt match_length; /* length of best match */
- IPos prev_match; /* previous match */
- int match_available; /* set if previous match exists */
- uInt strstart; /* start of string to insert */
- uInt match_start; /* start of matching string */
- uInt lookahead; /* number of valid bytes ahead in window */
-
- uInt prev_length;
-
- uInt max_chain_length;
-
- uInt max_lazy_match;
- # define max_insert_length max_lazy_match
-
- int level; /* compression level (1..9) */
- int strategy; /* favor or force Huffman coding*/
-
- uInt good_match;
-
- int nice_match; /* Stop searching when current match exceeds this */
-
- struct ct_data_s dyn_ltree[HEAP_SIZE]; /* literal and length tree */
- struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
- struct ct_data_s bl_tree[2*BL_CODES+1]; /* Huffman tree for bit lengths */
-
- struct tree_desc_s l_desc; /* desc. for literal tree */
- struct tree_desc_s d_desc; /* desc. for distance tree */
- struct tree_desc_s bl_desc; /* desc. for bit length tree */
-
- ush bl_count[MAX_BITS+1];
- /* number of codes at each bit length for an optimal tree */
-
- int heap[2*L_CODES+1]; /* heap used to build the Huffman trees */
- int heap_len; /* number of elements in the heap */
- int heap_max; /* element of largest frequency */
-
- uch depth[2*L_CODES+1];
- /* Depth of each subtree used as tie breaker for trees of equal frequency
- */
-
- uchf *l_buf; /* buffer for literals or lengths */
-
- uInt lit_bufsize;
-
- uInt last_lit; /* running index in l_buf */
-
- ushf *d_buf;
-
- ulg opt_len; /* bit length of current block with optimal trees */
- ulg static_len; /* bit length of current block with static trees */
- uInt matches; /* number of string matches in current block */
- int last_eob_len; /* bit length of EOB code for last block */
-
- #ifdef DEBUG
- ulg compressed_len; /* total bit length of compressed file mod 2^32 */
- ulg bits_sent; /* bit length of compressed data sent mod 2^32 */
- #endif
-
- ush bi_buf;
- int bi_valid;
-
- } FAR deflate_state;
-
- /* Output a byte on the stream.
- * IN assertion: there is enough room in pending_buf.
- */
- #define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
-
-
- #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
- /* Minimum amount of lookahead, except at the end of the input file.
- * See deflate.c for comments about the MIN_MATCH+1.
- */
-
- #define MAX_DIST(s) ((s)->w_size-MIN_LOOKAHEAD)
- /* In order to simplify the code, particularly on 16 bit machines, match
- * distances are limited to MAX_DIST instead of WSIZE.
- */
-
- /* in trees.c */
- void _tr_init OF((deflate_state *s));
- int _tr_tally OF((deflate_state *s, unsigned dist, unsigned lc));
- void _tr_flush_block OF((deflate_state *s, charf *buf, ulg stored_len,
- int eof));
- void _tr_align OF((deflate_state *s));
- void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
- int eof));
-
- #define d_code(dist) \
- ((dist) < 256 ? _dist_code[dist] : _dist_code[256+((dist)>>7)])
- /* Mapping from a distance to a distance code. dist is the distance - 1 and
- * must not have side effects. _dist_code[256] and _dist_code[257] are never
- * used.
- */
-
- #ifndef DEBUG
- /* Inline versions of _tr_tally for speed: */
-
- #if defined(GEN_TREES_H) || !defined(STDC)
- extern uch _length_code[];
- extern uch _dist_code[];
- #else
- extern const uch _length_code[];
- extern const uch _dist_code[];
- #endif
-
- # define _tr_tally_lit(s, c, flush) \
- { uch cc = (c); \
- s->d_buf[s->last_lit] = 0; \
- s->l_buf[s->last_lit++] = cc; \
- s->dyn_ltree[cc].Freq++; \
- flush = (s->last_lit == s->lit_bufsize-1); \
- }
- # define _tr_tally_dist(s, distance, length, flush) \
- { uch len = (length); \
- ush dist = (distance); \
- s->d_buf[s->last_lit] = dist; \
- s->l_buf[s->last_lit++] = len; \
- dist--; \
- s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
- s->dyn_dtree[d_code(dist)].Freq++; \
- flush = (s->last_lit == s->lit_bufsize-1); \
- }
- #else
- # define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c)
- # define _tr_tally_dist(s, distance, length, flush) \
- flush = _tr_tally(s, distance, length)
- #endif
-
- #endif
-