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TOMOYO Linux Cross Reference
Linux/lib/zlib_deflate/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 
 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  * Flush the bit buffer, keeping at most 7 bits in it.
297  */
298 static inline void bi_flush(deflate_state *s)
299 {
300     if (s->bi_valid == 16) {
301         put_short(s, s->bi_buf);
302         s->bi_buf = 0;
303         s->bi_valid = 0;
304     } else if (s->bi_valid >= 8) {
305         put_byte(s, (Byte)s->bi_buf);
306         s->bi_buf >>= 8;
307         s->bi_valid -= 8;
308     }
309 }
310 
311 /* ===========================================================================
312  * Flush the bit buffer and align the output on a byte boundary
313  */
314 static inline void bi_windup(deflate_state *s)
315 {
316     if (s->bi_valid > 8) {
317         put_short(s, s->bi_buf);
318     } else if (s->bi_valid > 0) {
319         put_byte(s, (Byte)s->bi_buf);
320     }
321     s->bi_buf = 0;
322     s->bi_valid = 0;
323 #ifdef DEBUG_ZLIB
324     s->bits_sent = (s->bits_sent+7) & ~7;
325 #endif
326 }
327 
328 

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