openshot-audio  0.1.2
deflate.h
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1 /* deflate.h -- internal compression state
2  * Copyright (C) 1995-2004 Jean-loup Gailly
3  * For conditions of distribution and use, see copyright notice in zlib.h
4  */
5 
6 /* WARNING: this file should *not* be used by applications. It is
7  part of the implementation of the compression library and is
8  subject to change. Applications should only use zlib.h.
9  */
10 
11 /* @(#) $Id: deflate.h,v 1.1 2007/06/07 17:54:37 jules_rms Exp $ */
12 
13 #ifndef DEFLATE_H
14 #define DEFLATE_H
15 
16 #include "zutil.h"
17 
18 /* define NO_GZIP when compiling if you want to disable gzip header and
19  trailer creation by deflate(). NO_GZIP would be used to avoid linking in
20  the crc code when it is not needed. For shared libraries, gzip encoding
21  should be left enabled. */
22 #ifndef NO_GZIP
23 # define GZIP
24 #endif
25 
26 #define NO_DUMMY_DECL
27 
28 /* ===========================================================================
29  * Internal compression state.
30  */
31 
32 #define LENGTH_CODES 29
33 /* number of length codes, not counting the special END_BLOCK code */
34 
35 #define LITERALS 256
36 /* number of literal bytes 0..255 */
37 
38 #define L_CODES (LITERALS+1+LENGTH_CODES)
39 /* number of Literal or Length codes, including the END_BLOCK code */
40 
41 #define D_CODES 30
42 /* number of distance codes */
43 
44 #define BL_CODES 19
45 /* number of codes used to transfer the bit lengths */
46 
47 #define HEAP_SIZE (2*L_CODES+1)
48 /* maximum heap size */
49 
50 #define MAX_BITS 15
51 /* All codes must not exceed MAX_BITS bits */
52 
53 #define INIT_STATE 42
54 #define EXTRA_STATE 69
55 #define NAME_STATE 73
56 #define COMMENT_STATE 91
57 #define HCRC_STATE 103
58 #define BUSY_STATE 113
59 #define FINISH_STATE 666
60 /* Stream status */
61 
62 
63 /* Data structure describing a single value and its code string. */
64 typedef struct ct_data_s {
65  union {
66  ush freq; /* frequency count */
67  ush code; /* bit string */
68  } fc;
69  union {
70  ush dad; /* father node in Huffman tree */
71  ush len; /* length of bit string */
72  } dl;
73 } FAR ct_data;
74 
75 #define Freq fc.freq
76 #define Code fc.code
77 #define Dad dl.dad
78 #define Len dl.len
79 
81 
82 typedef struct tree_desc_s {
83  ct_data *dyn_tree; /* the dynamic tree */
84  int max_code; /* largest code with non zero frequency */
85  static_tree_desc *stat_desc; /* the corresponding static tree */
86 } FAR tree_desc;
87 
88 typedef ush Pos;
89 typedef Pos FAR Posf;
90 typedef unsigned IPos;
91 
92 /* A Pos is an index in the character window. We use short instead of int to
93  * save space in the various tables. IPos is used only for parameter passing.
94  */
95 
96 typedef struct internal_state {
97  z_streamp strm; /* pointer back to this zlib stream */
98  int status; /* as the name implies */
99  Bytef *pending_buf; /* output still pending */
100  ulg pending_buf_size; /* size of pending_buf */
101  Bytef *pending_out; /* next pending byte to output to the stream */
102  uInt pending; /* nb of bytes in the pending buffer */
103  int wrap; /* bit 0 true for zlib, bit 1 true for gzip */
104  gz_headerp gzhead; /* gzip header information to write */
105  uInt gzindex; /* where in extra, name, or comment */
106  Byte method; /* STORED (for zip only) or DEFLATED */
107  int last_flush; /* value of flush param for previous deflate call */
108 
109  /* used by deflate.c: */
110 
111  uInt w_size; /* LZ77 window size (32K by default) */
112  uInt w_bits; /* log2(w_size) (8..16) */
113  uInt w_mask; /* w_size - 1 */
114 
116  /* Sliding window. Input bytes are read into the second half of the window,
117  * and move to the first half later to keep a dictionary of at least wSize
118  * bytes. With this organization, matches are limited to a distance of
119  * wSize-MAX_MATCH bytes, but this ensures that IO is always
120  * performed with a length multiple of the block size. Also, it limits
121  * the window size to 64K, which is quite useful on MSDOS.
122  * To do: use the user input buffer as sliding window.
123  */
124 
126  /* Actual size of window: 2*wSize, except when the user input buffer
127  * is directly used as sliding window.
128  */
129 
131  /* Link to older string with same hash index. To limit the size of this
132  * array to 64K, this link is maintained only for the last 32K strings.
133  * An index in this array is thus a window index modulo 32K.
134  */
135 
136  Posf *head; /* Heads of the hash chains or NIL. */
137 
138  uInt ins_h; /* hash index of string to be inserted */
139  uInt hash_size; /* number of elements in hash table */
140  uInt hash_bits; /* log2(hash_size) */
141  uInt hash_mask; /* hash_size-1 */
142 
144  /* Number of bits by which ins_h must be shifted at each input
145  * step. It must be such that after MIN_MATCH steps, the oldest
146  * byte no longer takes part in the hash key, that is:
147  * hash_shift * MIN_MATCH >= hash_bits
148  */
149 
151  /* Window position at the beginning of the current output block. Gets
152  * negative when the window is moved backwards.
153  */
154 
155  uInt match_length; /* length of best match */
156  IPos prev_match; /* previous match */
157  int match_available; /* set if previous match exists */
158  uInt strstart; /* start of string to insert */
159  uInt match_start; /* start of matching string */
160  uInt lookahead; /* number of valid bytes ahead in window */
161 
163  /* Length of the best match at previous step. Matches not greater than this
164  * are discarded. This is used in the lazy match evaluation.
165  */
166 
168  /* To speed up deflation, hash chains are never searched beyond this
169  * length. A higher limit improves compression ratio but degrades the
170  * speed.
171  */
172 
174  /* Attempt to find a better match only when the current match is strictly
175  * smaller than this value. This mechanism is used only for compression
176  * levels >= 4.
177  */
178 # define max_insert_length max_lazy_match
179  /* Insert new strings in the hash table only if the match length is not
180  * greater than this length. This saves time but degrades compression.
181  * max_insert_length is used only for compression levels <= 3.
182  */
183 
184  int level; /* compression level (1..9) */
185  int strategy; /* favor or force Huffman coding*/
186 
188  /* Use a faster search when the previous match is longer than this */
189 
190  int nice_match; /* Stop searching when current match exceeds this */
191 
192  /* used by trees.c: */
193  /* Didn't use ct_data typedef below to supress compiler warning */
194  struct ct_data_s dyn_ltree[HEAP_SIZE]; /* literal and length tree */
195  struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
196  struct ct_data_s bl_tree[2*BL_CODES+1]; /* Huffman tree for bit lengths */
197 
198  struct tree_desc_s l_desc; /* desc. for literal tree */
199  struct tree_desc_s d_desc; /* desc. for distance tree */
200  struct tree_desc_s bl_desc; /* desc. for bit length tree */
201 
202  ush bl_count[MAX_BITS+1];
203  /* number of codes at each bit length for an optimal tree */
204 
205  int heap[2*L_CODES+1]; /* heap used to build the Huffman trees */
206  int heap_len; /* number of elements in the heap */
207  int heap_max; /* element of largest frequency */
208  /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
209  * The same heap array is used to build all trees.
210  */
211 
212  uch depth[2*L_CODES+1];
213  /* Depth of each subtree used as tie breaker for trees of equal frequency
214  */
215 
216  uchf *l_buf; /* buffer for literals or lengths */
217 
219  /* Size of match buffer for literals/lengths. There are 4 reasons for
220  * limiting lit_bufsize to 64K:
221  * - frequencies can be kept in 16 bit counters
222  * - if compression is not successful for the first block, all input
223  * data is still in the window so we can still emit a stored block even
224  * when input comes from standard input. (This can also be done for
225  * all blocks if lit_bufsize is not greater than 32K.)
226  * - if compression is not successful for a file smaller than 64K, we can
227  * even emit a stored file instead of a stored block (saving 5 bytes).
228  * This is applicable only for zip (not gzip or zlib).
229  * - creating new Huffman trees less frequently may not provide fast
230  * adaptation to changes in the input data statistics. (Take for
231  * example a binary file with poorly compressible code followed by
232  * a highly compressible string table.) Smaller buffer sizes give
233  * fast adaptation but have of course the overhead of transmitting
234  * trees more frequently.
235  * - I can't count above 4
236  */
237 
238  uInt last_lit; /* running index in l_buf */
239 
241  /* Buffer for distances. To simplify the code, d_buf and l_buf have
242  * the same number of elements. To use different lengths, an extra flag
243  * array would be necessary.
244  */
245 
246  ulg opt_len; /* bit length of current block with optimal trees */
247  ulg static_len; /* bit length of current block with static trees */
248  uInt matches; /* number of string matches in current block */
249  int last_eob_len; /* bit length of EOB code for last block */
250 
251 #ifdef DEBUG
252  ulg compressed_len; /* total bit length of compressed file mod 2^32 */
253  ulg bits_sent; /* bit length of compressed data sent mod 2^32 */
254 #endif
255 
257  /* Output buffer. bits are inserted starting at the bottom (least
258  * significant bits).
259  */
260  int bi_valid;
261  /* Number of valid bits in bi_buf. All bits above the last valid bit
262  * are always zero.
263  */
264 
266 
267 /* Output a byte on the stream.
268  * IN assertion: there is enough room in pending_buf.
269  */
270 #define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
271 
272 
273 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
274 /* Minimum amount of lookahead, except at the end of the input file.
275  * See deflate.c for comments about the MIN_MATCH+1.
276  */
277 
278 #define MAX_DIST(s) ((s)->w_size-MIN_LOOKAHEAD)
279 /* In order to simplify the code, particularly on 16 bit machines, match
280  * distances are limited to MAX_DIST instead of WSIZE.
281  */
282 
283  /* in trees.c */
284 void _tr_init OF((deflate_state *s));
285 int _tr_tally OF((deflate_state *s, unsigned dist, unsigned lc));
286 void _tr_flush_block OF((deflate_state *s, charf *buf, ulg stored_len,
287  int eof));
288 void _tr_align OF((deflate_state *s));
289 void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
290  int eof));
291 
292 #define d_code(dist) \
293  ((dist) < 256 ? _dist_code[dist] : _dist_code[256+((dist)>>7)])
294 /* Mapping from a distance to a distance code. dist is the distance - 1 and
295  * must not have side effects. _dist_code[256] and _dist_code[257] are never
296  * used.
297  */
298 
299 #ifndef DEBUG
300 /* Inline versions of _tr_tally for speed: */
301 
302 #if defined(GEN_TREES_H) || !defined(STDC)
303  extern uch _length_code[];
304  extern uch _dist_code[];
305 #else
306  extern const uch _length_code[];
307  extern const uch _dist_code[];
308 #endif
309 
310 # define _tr_tally_lit(s, c, flush) \
311  { uch cc = (c); \
312  s->d_buf[s->last_lit] = 0; \
313  s->l_buf[s->last_lit++] = cc; \
314  s->dyn_ltree[cc].Freq++; \
315  flush = (s->last_lit == s->lit_bufsize-1); \
316  }
317 # define _tr_tally_dist(s, distance, length, flush) \
318  { uch len = (length); \
319  ush dist = (distance); \
320  s->d_buf[s->last_lit] = dist; \
321  s->l_buf[s->last_lit++] = len; \
322  dist--; \
323  s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
324  s->dyn_dtree[d_code(dist)].Freq++; \
325  flush = (s->last_lit == s->lit_bufsize-1); \
326  }
327 #else
328 # define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c)
329 # define _tr_tally_dist(s, distance, length, flush) \
330  flush = _tr_tally(s, distance, length)
331 #endif
332 
333 #endif /* DEFLATE_H */
uInt good_match
Definition: deflate.h:187
uInt hash_bits
Definition: deflate.h:140
ulg static_len
Definition: deflate.h:247
Definition: deflate.c:161
int heap_len
Definition: deflate.h:206
int heap_max
Definition: deflate.h:207
uInt w_mask
Definition: deflate.h:113
ush FAR ushf
Definition: zutil.h:50
Bytef * window
Definition: deflate.h:115
#define BL_CODES
Definition: deflate.h:44
unsigned char Byte
Definition: zconf.h:274
uInt max_lazy_match
Definition: deflate.h:173
uInt hash_mask
Definition: deflate.h:141
union ct_data_s::@78 dl
uInt match_length
Definition: deflate.h:155
#define MAX_BITS
Definition: deflate.h:50
ush Pos
Definition: deflate.h:88
uInt hash_shift
Definition: deflate.h:143
int status
Definition: deflate.h:98
int strategy
Definition: deflate.h:185
uInt prev_length
Definition: deflate.h:162
void _tr_init(deflate_state *s)
Definition: trees.c:379
Posf * prev
Definition: deflate.h:130
ct_data * dyn_tree
Definition: deflate.h:83
static_tree_desc * stat_desc
Definition: deflate.h:85
Bytef * pending_out
Definition: deflate.h:101
uInt match_start
Definition: deflate.h:159
gz_header FAR * gz_headerp
Definition: zlib.h:127
#define FAR
ush code
Definition: deflate.h:67
gz_headerp gzhead
Definition: deflate.h:104
Byte FAR Bytef
Definition: zconf.h:283
uInt lookahead
Definition: deflate.h:160
int max_code
Definition: deflate.h:84
ulg window_size
Definition: deflate.h:125
void _tr_stored_block(deflate_state *s, charf *buf, ulg stored_len, int eof)
Definition: trees.c:853
uch _dist_code[]
Definition: trees.c:102
int level
Definition: deflate.h:184
void _tr_init OF((deflate_state *s))
int last_eob_len
Definition: deflate.h:249
z_streamp strm
Definition: deflate.h:97
ulg opt_len
Definition: deflate.h:246
Posf * head
Definition: deflate.h:136
void _tr_align(deflate_state *s)
Definition: trees.c:874
ush dad
Definition: deflate.h:70
unsigned short ush
Definition: zutil.h:49
ush freq
Definition: deflate.h:66
uInt w_size
Definition: deflate.h:111
uchf * l_buf
Definition: deflate.h:216
Definition: deflate.h:82
Pos FAR Posf
Definition: deflate.h:89
#define HEAP_SIZE
Definition: deflate.h:47
int wrap
Definition: deflate.h:103
uch _length_code[]
Definition: trees.c:108
Bytef * pending_buf
Definition: deflate.h:99
ush bi_buf
Definition: deflate.h:256
uInt lit_bufsize
Definition: deflate.h:218
ushf * d_buf
Definition: deflate.h:240
long block_start
Definition: deflate.h:150
int match_available
Definition: deflate.h:157
uInt gzindex
Definition: deflate.h:105
struct ct_data_s ct_data
uInt max_chain_length
Definition: deflate.h:167
int nice_match
Definition: deflate.h:190
struct internal_state deflate_state
int _tr_tally(deflate_state *s, unsigned dist, unsigned lc)
Definition: trees.c:1002
Definition: deflate.h:96
uInt last_lit
Definition: deflate.h:238
unsigned char uch
Definition: zutil.h:47
uInt w_bits
Definition: deflate.h:112
uInt pending
Definition: deflate.h:102
unsigned long ulg
Definition: zutil.h:51
uInt strstart
Definition: deflate.h:158
ulg pending_buf_size
Definition: deflate.h:100
ush len
Definition: deflate.h:71
Definition: deflate.h:64
void _tr_flush_block(deflate_state *s, charf *buf, ulg stored_len, int eof)
Definition: trees.c:902
uInt matches
Definition: deflate.h:248
z_stream FAR * z_streamp
Definition: zlib.h:104
IPos prev_match
Definition: deflate.h:156
union ct_data_s::@77 fc
int last_flush
Definition: deflate.h:107
#define D_CODES
Definition: deflate.h:41
int bi_valid
Definition: deflate.h:260
uch FAR uchf
Definition: zutil.h:48
uInt hash_size
Definition: deflate.h:139
uInt ins_h
Definition: deflate.h:138
Byte method
Definition: deflate.h:106
unsigned int uInt
Definition: zconf.h:276
char FAR charf
Definition: zconf.h:285
struct tree_desc_s tree_desc
unsigned IPos
Definition: deflate.h:90
#define L_CODES
Definition: deflate.h:38