Branch data Line data Source code
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 : : } 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 : : } tree_desc;
63 : :
64 : : typedef ush Pos;
65 : : typedef unsigned IPos;
66 : :
67 : : /* A Pos is an index in the character window. We use short instead of int to
68 : : * save space in the various tables. IPos is used only for parameter passing.
69 : : */
70 : :
71 : : typedef struct deflate_state {
72 : : z_streamp strm; /* pointer back to this zlib stream */
73 : : int status; /* as the name implies */
74 : : Byte *pending_buf; /* output still pending */
75 : : ulg pending_buf_size; /* size of pending_buf */
76 : : Byte *pending_out; /* next pending byte to output to the stream */
77 : : int pending; /* nb of bytes in the pending buffer */
78 : : int noheader; /* suppress zlib header and adler32 */
79 : : Byte data_type; /* UNKNOWN, BINARY or ASCII */
80 : : Byte method; /* STORED (for zip only) or DEFLATED */
81 : : int last_flush; /* value of flush param for previous deflate call */
82 : :
83 : : /* used by deflate.c: */
84 : :
85 : : uInt w_size; /* LZ77 window size (32K by default) */
86 : : uInt w_bits; /* log2(w_size) (8..16) */
87 : : uInt w_mask; /* w_size - 1 */
88 : :
89 : : Byte *window;
90 : : /* Sliding window. Input bytes are read into the second half of the window,
91 : : * and move to the first half later to keep a dictionary of at least wSize
92 : : * bytes. With this organization, matches are limited to a distance of
93 : : * wSize-MAX_MATCH bytes, but this ensures that IO is always
94 : : * performed with a length multiple of the block size. Also, it limits
95 : : * the window size to 64K, which is quite useful on MSDOS.
96 : : * To do: use the user input buffer as sliding window.
97 : : */
98 : :
99 : : ulg window_size;
100 : : /* Actual size of window: 2*wSize, except when the user input buffer
101 : : * is directly used as sliding window.
102 : : */
103 : :
104 : : Pos *prev;
105 : : /* Link to older string with same hash index. To limit the size of this
106 : : * array to 64K, this link is maintained only for the last 32K strings.
107 : : * An index in this array is thus a window index modulo 32K.
108 : : */
109 : :
110 : : Pos *head; /* Heads of the hash chains or NIL. */
111 : :
112 : : uInt ins_h; /* hash index of string to be inserted */
113 : : uInt hash_size; /* number of elements in hash table */
114 : : uInt hash_bits; /* log2(hash_size) */
115 : : uInt hash_mask; /* hash_size-1 */
116 : :
117 : : uInt hash_shift;
118 : : /* Number of bits by which ins_h must be shifted at each input
119 : : * step. It must be such that after MIN_MATCH steps, the oldest
120 : : * byte no longer takes part in the hash key, that is:
121 : : * hash_shift * MIN_MATCH >= hash_bits
122 : : */
123 : :
124 : : long block_start;
125 : : /* Window position at the beginning of the current output block. Gets
126 : : * negative when the window is moved backwards.
127 : : */
128 : :
129 : : uInt match_length; /* length of best match */
130 : : IPos prev_match; /* previous match */
131 : : int match_available; /* set if previous match exists */
132 : : uInt strstart; /* start of string to insert */
133 : : uInt match_start; /* start of matching string */
134 : : uInt lookahead; /* number of valid bytes ahead in window */
135 : :
136 : : uInt prev_length;
137 : : /* Length of the best match at previous step. Matches not greater than this
138 : : * are discarded. This is used in the lazy match evaluation.
139 : : */
140 : :
141 : : uInt max_chain_length;
142 : : /* To speed up deflation, hash chains are never searched beyond this
143 : : * length. A higher limit improves compression ratio but degrades the
144 : : * speed.
145 : : */
146 : :
147 : : uInt max_lazy_match;
148 : : /* Attempt to find a better match only when the current match is strictly
149 : : * smaller than this value. This mechanism is used only for compression
150 : : * levels >= 4.
151 : : */
152 : : # define max_insert_length max_lazy_match
153 : : /* Insert new strings in the hash table only if the match length is not
154 : : * greater than this length. This saves time but degrades compression.
155 : : * max_insert_length is used only for compression levels <= 3.
156 : : */
157 : :
158 : : int level; /* compression level (1..9) */
159 : : int strategy; /* favor or force Huffman coding*/
160 : :
161 : : uInt good_match;
162 : : /* Use a faster search when the previous match is longer than this */
163 : :
164 : : int nice_match; /* Stop searching when current match exceeds this */
165 : :
166 : : /* used by trees.c: */
167 : : /* Didn't use ct_data typedef below to suppress compiler warning */
168 : : struct ct_data_s dyn_ltree[HEAP_SIZE]; /* literal and length tree */
169 : : struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
170 : : struct ct_data_s bl_tree[2*BL_CODES+1]; /* Huffman tree for bit lengths */
171 : :
172 : : struct tree_desc_s l_desc; /* desc. for literal tree */
173 : : struct tree_desc_s d_desc; /* desc. for distance tree */
174 : : struct tree_desc_s bl_desc; /* desc. for bit length tree */
175 : :
176 : : ush bl_count[MAX_BITS+1];
177 : : /* number of codes at each bit length for an optimal tree */
178 : :
179 : : int heap[2*L_CODES+1]; /* heap used to build the Huffman trees */
180 : : int heap_len; /* number of elements in the heap */
181 : : int heap_max; /* element of largest frequency */
182 : : /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
183 : : * The same heap array is used to build all trees.
184 : : */
185 : :
186 : : uch depth[2*L_CODES+1];
187 : : /* Depth of each subtree used as tie breaker for trees of equal frequency
188 : : */
189 : :
190 : : uch *l_buf; /* buffer for literals or lengths */
191 : :
192 : : uInt lit_bufsize;
193 : : /* Size of match buffer for literals/lengths. There are 4 reasons for
194 : : * limiting lit_bufsize to 64K:
195 : : * - frequencies can be kept in 16 bit counters
196 : : * - if compression is not successful for the first block, all input
197 : : * data is still in the window so we can still emit a stored block even
198 : : * when input comes from standard input. (This can also be done for
199 : : * all blocks if lit_bufsize is not greater than 32K.)
200 : : * - if compression is not successful for a file smaller than 64K, we can
201 : : * even emit a stored file instead of a stored block (saving 5 bytes).
202 : : * This is applicable only for zip (not gzip or zlib).
203 : : * - creating new Huffman trees less frequently may not provide fast
204 : : * adaptation to changes in the input data statistics. (Take for
205 : : * example a binary file with poorly compressible code followed by
206 : : * a highly compressible string table.) Smaller buffer sizes give
207 : : * fast adaptation but have of course the overhead of transmitting
208 : : * trees more frequently.
209 : : * - I can't count above 4
210 : : */
211 : :
212 : : uInt last_lit; /* running index in l_buf */
213 : :
214 : : ush *d_buf;
215 : : /* Buffer for distances. To simplify the code, d_buf and l_buf have
216 : : * the same number of elements. To use different lengths, an extra flag
217 : : * array would be necessary.
218 : : */
219 : :
220 : : ulg opt_len; /* bit length of current block with optimal trees */
221 : : ulg static_len; /* bit length of current block with static trees */
222 : : ulg compressed_len; /* total bit length of compressed file */
223 : : uInt matches; /* number of string matches in current block */
224 : : int last_eob_len; /* bit length of EOB code for last block */
225 : :
226 : : #ifdef DEBUG_ZLIB
227 : : ulg bits_sent; /* bit length of the compressed data */
228 : : #endif
229 : :
230 : : ush bi_buf;
231 : : /* Output buffer. bits are inserted starting at the bottom (least
232 : : * significant bits).
233 : : */
234 : : int bi_valid;
235 : : /* Number of valid bits in bi_buf. All bits above the last valid bit
236 : : * are always zero.
237 : : */
238 : :
239 : : } deflate_state;
240 : :
241 : : typedef struct deflate_workspace {
242 : : /* State memory for the deflator */
243 : : deflate_state deflate_memory;
244 : : Byte *window_memory;
245 : : Pos *prev_memory;
246 : : Pos *head_memory;
247 : : char *overlay_memory;
248 : : } deflate_workspace;
249 : :
250 : : #define zlib_deflate_window_memsize(windowBits) \
251 : : (2 * (1 << (windowBits)) * sizeof(Byte))
252 : : #define zlib_deflate_prev_memsize(windowBits) \
253 : : ((1 << (windowBits)) * sizeof(Pos))
254 : : #define zlib_deflate_head_memsize(memLevel) \
255 : : ((1 << ((memLevel)+7)) * sizeof(Pos))
256 : : #define zlib_deflate_overlay_memsize(memLevel) \
257 : : ((1 << ((memLevel)+6)) * (sizeof(ush)+2))
258 : :
259 : : /* Output a byte on the stream.
260 : : * IN assertion: there is enough room in pending_buf.
261 : : */
262 : : #define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
263 : :
264 : :
265 : : #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
266 : : /* Minimum amount of lookahead, except at the end of the input file.
267 : : * See deflate.c for comments about the MIN_MATCH+1.
268 : : */
269 : :
270 : : #define MAX_DIST(s) ((s)->w_size-MIN_LOOKAHEAD)
271 : : /* In order to simplify the code, particularly on 16 bit machines, match
272 : : * distances are limited to MAX_DIST instead of WSIZE.
273 : : */
274 : :
275 : : /* in trees.c */
276 : : void zlib_tr_init (deflate_state *s);
277 : : int zlib_tr_tally (deflate_state *s, unsigned dist, unsigned lc);
278 : : ulg zlib_tr_flush_block (deflate_state *s, char *buf, ulg stored_len,
279 : : int eof);
280 : : void zlib_tr_align (deflate_state *s);
281 : : void zlib_tr_stored_block (deflate_state *s, char *buf, ulg stored_len,
282 : : int eof);
283 : : void zlib_tr_stored_type_only (deflate_state *);
284 : :
285 : :
286 : : /* ===========================================================================
287 : : * Output a short LSB first on the stream.
288 : : * IN assertion: there is enough room in pendingBuf.
289 : : */
290 : : #define put_short(s, w) { \
291 : : put_byte(s, (uch)((w) & 0xff)); \
292 : : put_byte(s, (uch)((ush)(w) >> 8)); \
293 : : }
294 : :
295 : : /* ===========================================================================
296 : : * Reverse the first len bits of a code, using straightforward code (a faster
297 : : * method would use a table)
298 : : * IN assertion: 1 <= len <= 15
299 : : */
300 : : static inline unsigned bi_reverse(unsigned code, /* the value to invert */
301 : : int len) /* its bit length */
302 : : {
303 : : register unsigned res = 0;
304 : : do {
305 : 0 : res |= code & 1;
306 : 0 : code >>= 1, res <<= 1;
307 [ # # ][ # # ]: 0 : } while (--len > 0);
308 : 0 : return res >> 1;
309 : : }
310 : :
311 : : /* ===========================================================================
312 : : * Flush the bit buffer, keeping at most 7 bits in it.
313 : : */
314 : : static inline void bi_flush(deflate_state *s)
315 : : {
316 [ # # ][ # # ]: 0 : if (s->bi_valid == 16) {
317 : 0 : put_short(s, s->bi_buf);
318 : 0 : s->bi_buf = 0;
319 : 0 : s->bi_valid = 0;
320 [ # # ][ # # ]: 0 : } else if (s->bi_valid >= 8) {
321 : 0 : put_byte(s, (Byte)s->bi_buf);
322 : 0 : s->bi_buf >>= 8;
323 : 0 : s->bi_valid -= 8;
324 : : }
325 : : }
326 : :
327 : : /* ===========================================================================
328 : : * Flush the bit buffer and align the output on a byte boundary
329 : : */
330 : : static inline void bi_windup(deflate_state *s)
331 : : {
332 [ # # ][ # # ]: 0 : if (s->bi_valid > 8) {
[ # # ]
333 : 0 : put_short(s, s->bi_buf);
334 [ # # ][ # # ]: 0 : } else if (s->bi_valid > 0) {
[ # # ]
335 : 0 : put_byte(s, (Byte)s->bi_buf);
336 : : }
337 : 0 : s->bi_buf = 0;
338 : 0 : s->bi_valid = 0;
339 : : #ifdef DEBUG_ZLIB
340 : : s->bits_sent = (s->bits_sent+7) & ~7;
341 : : #endif
342 : : }
343 : :
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