1
2
3
4 #define Assert(err, str)
5 #define Trace(dummy)
6 #define Tracev(dummy)
7 #define Tracecv(err, dummy)
8 #define Tracevv(dummy)
9
10
11
12 #define LENGTH_CODES 29
13 /* number of length codes, not counting the special END_BLOCK code */
14
15 #define LITERALS 256
16 /* number of literal bytes 0..255 */
17
18 #define L_CODES (LITERALS+1+LENGTH_CODES)
19 /* number of Literal or Length codes, including the END_BLOCK code */
20
21 #define D_CODES 30
22 /* number of distance codes */
23
24 #define BL_CODES 19
25 /* number of codes used to transfer the bit lengths */
26
27 #define HEAP_SIZE (2*L_CODES+1)
28 /* maximum heap size */
29
30 #define MAX_BITS 15
31 /* All codes must not exceed MAX_BITS bits */
32
33 #define INIT_STATE 42
34 #define BUSY_STATE 113
35 #define FINISH_STATE 666
36 /* Stream status */
37
38
39 /* Data structure describing a single value and its code string. */
40 typedef struct ct_data_s {
41 union {
42 ush freq; /* frequency count */
43 ush code; /* bit string */
44 } fc;
45 union {
46 ush dad; /* father node in Huffman tree */
47 ush len; /* length of bit string */
48 } dl;
49 } FAR ct_data;
50
51 #define Freq fc.freq
52 #define Code fc.code
53 #define Dad dl.dad
54 #define Len dl.len
55
56 typedef struct static_tree_desc_s static_tree_desc;
57
58 typedef struct tree_desc_s {
59 ct_data *dyn_tree; /* the dynamic tree */
60 int max_code; /* largest code with non zero frequency */
61 static_tree_desc *stat_desc; /* the corresponding static tree */
62 } FAR tree_desc;
63
64 typedef ush Pos;
65 typedef Pos FAR Posf;
66 typedef unsigned IPos;
67
68 /* A Pos is an index in the character window. We use short instead of int to
69 * save space in the various tables. IPos is used only for parameter passing.
70 */
71
72 typedef struct deflate_state {
73 z_streamp strm; /* pointer back to this zlib stream */
74 int status; /* as the name implies */
75 Bytef *pending_buf; /* output still pending */
76 ulg pending_buf_size; /* size of pending_buf */
77 Bytef *pending_out; /* next pending byte to output to the stream */
78 int pending; /* nb of bytes in the pending buffer */
79 int noheader; /* suppress zlib header and adler32 */
80 Byte data_type; /* UNKNOWN, BINARY or ASCII */
81 Byte method; /* STORED (for zip only) or DEFLATED */
82 int last_flush; /* value of flush param for previous deflate call */
83
84 /* used by deflate.c: */
85
86 uInt w_size; /* LZ77 window size (32K by default) */
87 uInt w_bits; /* log2(w_size) (8..16) */
88 uInt w_mask; /* w_size - 1 */
89
90 Bytef *window;
91 /* Sliding window. Input bytes are read into the second half of the window,
92 * and move to the first half later to keep a dictionary of at least wSize
93 * bytes. With this organization, matches are limited to a distance of
94 * wSize-MAX_MATCH bytes, but this ensures that IO is always
95 * performed with a length multiple of the block size. Also, it limits
96 * the window size to 64K, which is quite useful on MSDOS.
97 * To do: use the user input buffer as sliding window.
98 */
99
100 ulg window_size;
101 /* Actual size of window: 2*wSize, except when the user input buffer
102 * is directly used as sliding window.
103 */
104
105 Posf *prev;
106 /* Link to older string with same hash index. To limit the size of this
107 * array to 64K, this link is maintained only for the last 32K strings.
108 * An index in this array is thus a window index modulo 32K.
109 */
110
111 Posf *head; /* Heads of the hash chains or NIL. */
112
113 uInt ins_h; /* hash index of string to be inserted */
114 uInt hash_size; /* number of elements in hash table */
115 uInt hash_bits; /* log2(hash_size) */
116 uInt hash_mask; /* hash_size-1 */
117
118 uInt hash_shift;
119 /* Number of bits by which ins_h must be shifted at each input
120 * step. It must be such that after MIN_MATCH steps, the oldest
121 * byte no longer takes part in the hash key, that is:
122 * hash_shift * MIN_MATCH >= hash_bits
123 */
124
125 long block_start;
126 /* Window position at the beginning of the current output block. Gets
127 * negative when the window is moved backwards.
128 */
129
130 uInt match_length; /* length of best match */
131 IPos prev_match; /* previous match */
132 int match_available; /* set if previous match exists */
133 uInt strstart; /* start of string to insert */
134 uInt match_start; /* start of matching string */
135 uInt lookahead; /* number of valid bytes ahead in window */
136
137 uInt prev_length;
138 /* Length of the best match at previous step. Matches not greater than this
139 * are discarded. This is used in the lazy match evaluation.
140 */
141
142 uInt max_chain_length;
143 /* To speed up deflation, hash chains are never searched beyond this
144 * length. A higher limit improves compression ratio but degrades the
145 * speed.
146 */
147
148 uInt max_lazy_match;
149 /* Attempt to find a better match only when the current match is strictly
150 * smaller than this value. This mechanism is used only for compression
151 * levels >= 4.
152 */
153 # define max_insert_length max_lazy_match
154 /* Insert new strings in the hash table only if the match length is not
155 * greater than this length. This saves time but degrades compression.
156 * max_insert_length is used only for compression levels <= 3.
157 */
158
159 int level; /* compression level (1..9) */
160 int strategy; /* favor or force Huffman coding*/
161
162 uInt good_match;
163 /* Use a faster search when the previous match is longer than this */
164
165 int nice_match; /* Stop searching when current match exceeds this */
166
167 /* used by trees.c: */
168 /* Didn't use ct_data typedef below to supress compiler warning */
169 struct ct_data_s dyn_ltree[HEAP_SIZE]; /* literal and length tree */
170 struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
171 struct ct_data_s bl_tree[2*BL_CODES+1]; /* Huffman tree for bit lengths */
172
173 struct tree_desc_s l_desc; /* desc. for literal tree */
174 struct tree_desc_s d_desc; /* desc. for distance tree */
175 struct tree_desc_s bl_desc; /* desc. for bit length tree */
176
177 ush bl_count[MAX_BITS+1];
178 /* number of codes at each bit length for an optimal tree */
179
180 int heap[2*L_CODES+1]; /* heap used to build the Huffman trees */
181 int heap_len; /* number of elements in the heap */
182 int heap_max; /* element of largest frequency */
183 /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
184 * The same heap array is used to build all trees.
185 */
186
187 uch depth[2*L_CODES+1];
188 /* Depth of each subtree used as tie breaker for trees of equal frequency
189 */
190
191 uchf *l_buf; /* buffer for literals or lengths */
192
193 uInt lit_bufsize;
194 /* Size of match buffer for literals/lengths. There are 4 reasons for
195 * limiting lit_bufsize to 64K:
196 * - frequencies can be kept in 16 bit counters
197 * - if compression is not successful for the first block, all input
198 * data is still in the window so we can still emit a stored block even
199 * when input comes from standard input. (This can also be done for
200 * all blocks if lit_bufsize is not greater than 32K.)
201 * - if compression is not successful for a file smaller than 64K, we can
202 * even emit a stored file instead of a stored block (saving 5 bytes).
203 * This is applicable only for zip (not gzip or zlib).
204 * - creating new Huffman trees less frequently may not provide fast
205 * adaptation to changes in the input data statistics. (Take for
206 * example a binary file with poorly compressible code followed by
207 * a highly compressible string table.) Smaller buffer sizes give
208 * fast adaptation but have of course the overhead of transmitting
209 * trees more frequently.
210 * - I can't count above 4
211 */
212
213 uInt last_lit; /* running index in l_buf */
214
215 ushf *d_buf;
216 /* Buffer for distances. To simplify the code, d_buf and l_buf have
217 * the same number of elements. To use different lengths, an extra flag
218 * array would be necessary.
219 */
220
221 ulg opt_len; /* bit length of current block with optimal trees */
222 ulg static_len; /* bit length of current block with static trees */
223 ulg compressed_len; /* total bit length of compressed file */
224 uInt matches; /* number of string matches in current block */
225 int last_eob_len; /* bit length of EOB code for last block */
226
227 #ifdef DEBUG_ZLIB
228 ulg bits_sent; /* bit length of the compressed data */
229 #endif
230
231 ush bi_buf;
232 /* Output buffer. bits are inserted starting at the bottom (least
233 * significant bits).
234 */
235 int bi_valid;
236 /* Number of valid bits in bi_buf. All bits above the last valid bit
237 * are always zero.
238 */
239
240 } FAR deflate_state;
241
242 typedef struct deflate_workspace {
243 /* State memory for the deflator */
244 deflate_state deflate_memory;
245 Byte window_memory[2 * (1 << MAX_WBITS)];
246 Pos prev_memory[1 << MAX_WBITS];
247 Pos head_memory[1 << (MAX_MEM_LEVEL + 7)];
248 char overlay_memory[(1 << (MAX_MEM_LEVEL + 6)) * (sizeof(ush)+2)];
249 } deflate_workspace;
250
251 /* Output a byte on the stream.
252 * IN assertion: there is enough room in pending_buf.
253 */
254 #define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
255
256
257 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
258 /* Minimum amount of lookahead, except at the end of the input file.
259 * See deflate.c for comments about the MIN_MATCH+1.
260 */
261
262 #define MAX_DIST(s) ((s)->w_size-MIN_LOOKAHEAD)
263 /* In order to simplify the code, particularly on 16 bit machines, match
264 * distances are limited to MAX_DIST instead of WSIZE.
265 */
266
267 /* in trees.c */
268 void zlib_tr_init OF((deflate_state *s));
269 int zlib_tr_tally OF((deflate_state *s, unsigned dist, unsigned lc));
270 ulg zlib_tr_flush_block OF((deflate_state *s, charf *buf, ulg stored_len,
271 int eof));
272 void zlib_tr_align OF((deflate_state *s));
273 void zlib_tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
274 int eof));
275 void zlib_tr_stored_type_only OF((deflate_state *));
276
277
278 /* ===========================================================================
279 * Output a short LSB first on the stream.
280 * IN assertion: there is enough room in pendingBuf.
281 */
282 #define put_short(s, w) { \
283 put_byte(s, (uch)((w) & 0xff)); \
284 put_byte(s, (uch)((ush)(w) >> 8)); \
285 }
286
287 /* ===========================================================================
288 * Reverse the first len bits of a code, using straightforward code (a faster
289 * method would use a table)
290 * IN assertion: 1 <= len <= 15
291 */
bi_reverse(unsigned code,int len)292 static inline unsigned bi_reverse(unsigned code, /* the value to invert */
293 int len) /* its bit length */
294 {
295 register unsigned res = 0;
296 do {
297 res |= code & 1;
298 code >>= 1, res <<= 1;
299 } while (--len > 0);
300 return res >> 1;
301 }
302
303 /* ===========================================================================
304 * Flush the bit buffer, keeping at most 7 bits in it.
305 */
bi_flush(deflate_state * s)306 static inline void bi_flush(deflate_state *s)
307 {
308 if (s->bi_valid == 16) {
309 put_short(s, s->bi_buf);
310 s->bi_buf = 0;
311 s->bi_valid = 0;
312 } else if (s->bi_valid >= 8) {
313 put_byte(s, (Byte)s->bi_buf);
314 s->bi_buf >>= 8;
315 s->bi_valid -= 8;
316 }
317 }
318
319 /* ===========================================================================
320 * Flush the bit buffer and align the output on a byte boundary
321 */
bi_windup(deflate_state * s)322 static inline void bi_windup(deflate_state *s)
323 {
324 if (s->bi_valid > 8) {
325 put_short(s, s->bi_buf);
326 } else if (s->bi_valid > 0) {
327 put_byte(s, (Byte)s->bi_buf);
328 }
329 s->bi_buf = 0;
330 s->bi_valid = 0;
331 #ifdef DEBUG_ZLIB
332 s->bits_sent = (s->bits_sent+7) & ~7;
333 #endif
334 }
335
336