lib/zlib/deflate.h

1 /* deflate.h -- internal compression state
2  * Copyright (C) 1995-2010 Jean-loup Gailly
31 /* number of length codes, not counting the special END_BLOCK code */
37 /* number of Literal or Length codes, including the END_BLOCK code */
69         ush  len;        /* length of bit string */
111     uInt  w_mask;        /* w_size - 1 */
114     /* Sliding window. Input bytes are read into the second half of the window,
115      * and move to the first half later to keep a dictionary of at least wSize
117      * wSize-MAX_MATCH bytes, but this ensures that IO is always
118      * performed with a length multiple of the block size. Also, it limits
139     uInt  hash_mask;      /* hash_size-1 */
153     uInt match_length;           /* length of best match */
161     /* Length of the best match at previous step. Matches not greater than this
167      * length.  A higher limit improves compression ratio but degrades the
177     /* Insert new strings in the hash table only if the match length is not
178      * greater than this length. This saves time but degrades compression.
192     struct ct_data_s dyn_ltree[HEAP_SIZE];   /* literal and length tree */
198     struct tree_desc_s bl_desc;              /* desc. for bit length tree */
201     /* number of codes at each bit length for an optimal tree */
219      *   - frequencies can be kept in 16 bit counters
220      *   - if compression is not successful for the first block, all input
224      *   - if compression is not successful for a file smaller than 64K, we can
227      *   - creating new Huffman trees less frequently may not provide fast
233      *   - I can't count above 4
244     ulg opt_len;        /* bit length of current block with optimal trees */
245     ulg static_len;     /* bit length of current block with static trees */
247     int last_eob_len;   /* bit length of EOB code for last block */
250     ulg compressed_len; /* total bit length of compressed file mod 2^32 */
251     ulg bits_sent;      /* bit length of compressed data sent mod 2^32 */
264     /* High water mark offset in window for initialized bytes -- bytes above
275 #define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
283 #define MAX_DIST(s)  ((s)->w_size-MIN_LOOKAHEAD)
303 /* Mapping from a distance to a distance code. dist is the distance - 1 and
321     s->d_buf[s->last_lit] = 0; \
322     s->l_buf[s->last_lit++] = cc; \
323     s->dyn_ltree[cc].Freq++; \
324     flush = (s->last_lit == s->lit_bufsize-1); \
326 # define _tr_tally_dist(s, distance, length, flush) \  argument
327   { uch len = (length); \
329     s->d_buf[s->last_lit] = dist; \
330     s->l_buf[s->last_lit++] = len; \
331     dist--; \
332     s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
333     s->dyn_dtree[d_code(dist)].Freq++; \
334     flush = (s->last_lit == s->lit_bufsize-1); \
338 # define _tr_tally_dist(s, distance, length, flush) \  argument
339               flush = _tr_tally(s, distance, length)