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defutil.h
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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 
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 
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 
100  /* Actual size of window: 2*wSize, except when the user input buffer
101  * is directly used as sliding window.
102  */
103 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 */
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 */
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);
281 void zlib_tr_stored_block (deflate_state *s, char *buf, ulg stored_len,
282  int eof);
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  res |= code & 1;
306  code >>= 1, res <<= 1;
307  } while (--len > 0);
308  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  if (s->bi_valid == 16) {
317  put_short(s, s->bi_buf);
318  s->bi_buf = 0;
319  s->bi_valid = 0;
320  } else if (s->bi_valid >= 8) {
321  put_byte(s, (Byte)s->bi_buf);
322  s->bi_buf >>= 8;
323  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  if (s->bi_valid > 8) {
333  put_short(s, s->bi_buf);
334  } else if (s->bi_valid > 0) {
335  put_byte(s, (Byte)s->bi_buf);
336  }
337  s->bi_buf = 0;
338  s->bi_valid = 0;
339 #ifdef DEBUG_ZLIB
340  s->bits_sent = (s->bits_sent+7) & ~7;
341 #endif
342 }
343