klibc/zlib/deflate.h

/* deflate.h -- internal compression state
 * Copyright (C) 1995-2004 Jean-loup Gailly
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/* WARNING: this file should *not* be used by applications. It is
   part of the implementation of the compression library and is
   subject to change. Applications should only use zlib.h.
 */

/* @(#) $Id: deflate.h,v 1.1 2005/02/27 23:15:39 hpa Exp $ */

#ifndef DEFLATE_H
#define DEFLATE_H

#include "zutil.h"

/* define NO_GZIP when compiling if you want to disable gzip header and
   trailer creation by deflate().  NO_GZIP would be used to avoid linking in
   the crc code when it is not needed.  For shared libraries, gzip encoding
   should be left enabled. */
#ifndef NO_GZIP
#  define GZIP
#endif

/* ===========================================================================
 * Internal compression state.
 */

#define LENGTH_CODES 29
/* number of length codes, not counting the special END_BLOCK code */

#define LITERALS  256
/* number of literal bytes 0..255 */

#define L_CODES (LITERALS+1+LENGTH_CODES)
/* number of Literal or Length codes, including the END_BLOCK code */

#define D_CODES   30
/* number of distance codes */

#define BL_CODES  19
/* number of codes used to transfer the bit lengths */

#define HEAP_SIZE (2*L_CODES+1)
/* maximum heap size */

#define MAX_BITS 15
/* All codes must not exceed MAX_BITS bits */

#define INIT_STATE    42
#define EXTRA_STATE   69
#define NAME_STATE    73
#define COMMENT_STATE 91
#define HCRC_STATE   103
#define BUSY_STATE   113
#define FINISH_STATE 666
/* Stream status */


/* Data structure describing a single value and its code string. */
typedef struct ct_data_s {
    union {
        ush  freq;       /* frequency count */
        ush  code;       /* bit string */
    } fc;
    union {
        ush  dad;        /* father node in Huffman tree */
        ush  len;        /* length of bit string */
    } dl;
} FAR ct_data;

#define Freq fc.freq
#define Code fc.code
#define Dad  dl.dad
#define Len  dl.len

typedef struct static_tree_desc_s  static_tree_desc;

typedef struct tree_desc_s {
    ct_data *dyn_tree;           /* the dynamic tree */
    int     max_code;            /* largest code with non zero frequency */
    static_tree_desc *stat_desc; /* the corresponding static tree */
} FAR tree_desc;

typedef ush Pos;
typedef Pos FAR Posf;
typedef unsigned IPos;

/* A Pos is an index in the character window. We use short instead of int to
 * save space in the various tables. IPos is used only for parameter passing.
 */

typedef struct internal_state {
    z_streamp strm;      /* pointer back to this zlib stream */
    int   status;        /* as the name implies */
    Bytef *pending_buf;  /* output still pending */
    ulg   pending_buf_size; /* size of pending_buf */
    Bytef *pending_out;  /* next pending byte to output to the stream */
    uInt   pending;      /* nb of bytes in the pending buffer */
    int   wrap;          /* bit 0 true for zlib, bit 1 true for gzip */
    gz_headerp  gzhead;  /* gzip header information to write */
    uInt   gzindex;      /* where in extra, name, or comment */
    Byte  method;        /* STORED (for zip only) or DEFLATED */
    int   last_flush;    /* value of flush param for previous deflate call */

                /* used by deflate.c: */

    uInt  w_size;        /* LZ77 window size (32K by default) */
    uInt  w_bits;        /* log2(w_size)  (8..16) */
    uInt  w_mask;        /* w_size - 1 */

    Bytef *window;
    /* Sliding window. Input bytes are read into the second half of the window,
     * and move to the first half later to keep a dictionary of at least wSize
     * bytes. With this organization, matches are limited to a distance of
     * wSize-MAX_MATCH bytes, but this ensures that IO is always
     * performed with a length multiple of the block size. Also, it limits
     * the window size to 64K, which is quite useful on MSDOS.
     * To do: use the user input buffer as sliding window.
     */

    ulg window_size;
    /* Actual size of window: 2*wSize, except when the user input buffer
     * is directly used as sliding window.
     */

    Posf *prev;
    /* Link to older string with same hash index. To limit the size of this
     * array to 64K, this link is maintained only for the last 32K strings.
     * An index in this array is thus a window index modulo 32K.
     */

    Posf *head; /* Heads of the hash chains or NIL. */

    uInt  ins_h;          /* hash index of string to be inserted */
    uInt  hash_size;      /* number of elements in hash table */
    uInt  hash_bits;      /* log2(hash_size) */
    uInt  hash_mask;      /* hash_size-1 */

    uInt  hash_shift;
    /* Number of bits by which ins_h must be shifted at each input
     * step. It must be such that after MIN_MATCH steps, the oldest
     * byte no longer takes part in the hash key, that is:
     *   hash_shift * MIN_MATCH >= hash_bits
     */

    long block_start;
    /* Window position at the beginning of the current output block. Gets
     * negative when the window is moved backwards.
     */

    uInt match_length;           /* length of best match */
    IPos prev_match;             /* previous match */
    int match_available;         /* set if previous match exists */
    uInt strstart;               /* start of string to insert */
    uInt match_start;            /* start of matching string */
    uInt lookahead;              /* number of valid bytes ahead in window */

    uInt prev_length;
    /* Length of the best match at previous step. Matches not greater than this
     * are discarded. This is used in the lazy match evaluation.
     */

    uInt max_chain_length;
    /* To speed up deflation, hash chains are never searched beyond this
     * length.  A higher limit improves compression ratio but degrades the
     * speed.
     */

    uInt max_lazy_match;
    /* Attempt to find a better match only when the current match is strictly
     * smaller than this value. This mechanism is used only for compression
     * levels >= 4.
     */
#   define max_insert_length  max_lazy_match
    /* Insert new strings in the hash table only if the match length is not
     * greater than this length. This saves time but degrades compression.
     * max_insert_length is used only for compression levels <= 3.
     */

    int level;    /* compression level (1..9) */
    int strategy; /* favor or force Huffman coding*/

    uInt good_match;
    /* Use a faster search when the previous match is longer than this */

    int nice_match; /* Stop searching when current match exceeds this */

                /* used by trees.c: */
    /* Didn't use ct_data typedef below to supress compiler warning */
    struct ct_data_s dyn_ltree[HEAP_SIZE];   /* literal and length tree */
    struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
    struct ct_data_s bl_tree[2*BL_CODES+1];  /* Huffman tree for bit lengths */

    struct tree_desc_s l_desc;               /* desc. for literal tree */
    struct tree_desc_s d_desc;               /* desc. for distance tree */
    struct tree_desc_s bl_desc;              /* desc. for bit length tree */

    ush bl_count[MAX_BITS+1];
    /* number of codes at each bit length for an optimal tree */

    int heap[2*L_CODES+1];      /* heap used to build the Huffman trees */
    int heap_len;               /* number of elements in the heap */
    int heap_max;               /* element of largest frequency */
    /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
     * The same heap array is used to build all trees.
     */

    uch depth[2*L_CODES+1];
    /* Depth of each subtree used as tie breaker for trees of equal frequency
     */

    uchf *l_buf;          /* buffer for literals or lengths */

    uInt  lit_bufsize;
    /* Size of match buffer for literals/lengths.  There are 4 reasons for
     * limiting lit_bufsize to 64K:
     *   - frequencies can be kept in 16 bit counters
     *   - if compression is not successful for the first block, all input
     *     data is still in the window so we can still emit a stored block even
     *     when input comes from standard input.  (This can also be done for
     *     all blocks if lit_bufsize is not greater than 32K.)
     *   - if compression is not successful for a file smaller than 64K, we can
     *     even emit a stored file instead of a stored block (saving 5 bytes).
     *     This is applicable only for zip (not gzip or zlib).
     *   - creating new Huffman trees less frequently may not provide fast
     *     adaptation to changes in the input data statistics. (Take for
     *     example a binary file with poorly compressible code followed by
     *     a highly compressible string table.) Smaller buffer sizes give
     *     fast adaptation but have of course the overhead of transmitting
     *     trees more frequently.
     *   - I can't count above 4
     */

    uInt last_lit;      /* running index in l_buf */

    ushf *d_buf;
    /* Buffer for distances. To simplify the code, d_buf and l_buf have
     * the same number of elements. To use different lengths, an extra flag
     * array would be necessary.
     */

    ulg opt_len;        /* bit length of current block with optimal trees */
    ulg static_len;     /* bit length of current block with static trees */
    uInt matches;       /* number of string matches in current block */
    int last_eob_len;   /* bit length of EOB code for last block */

#ifdef DEBUG
    ulg compressed_len; /* total bit length of compressed file mod 2^32 */
    ulg bits_sent;      /* bit length of compressed data sent mod 2^32 */
#endif

    ush bi_buf;
    /* Output buffer. bits are inserted starting at the bottom (least
     * significant bits).
     */
    int bi_valid;
    /* Number of valid bits in bi_buf.  All bits above the last valid bit
     * are always zero.
     */

} FAR deflate_state;

/* Output a byte on the stream.
 * IN assertion: there is enough room in pending_buf.
 */
#define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}


#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
/* Minimum amount of lookahead, except at the end of the input file.
 * See deflate.c for comments about the MIN_MATCH+1.
 */

#define MAX_DIST(s)  ((s)->w_size-MIN_LOOKAHEAD)
/* In order to simplify the code, particularly on 16 bit machines, match
 * distances are limited to MAX_DIST instead of WSIZE.
 */

        /* in trees.c */
void _tr_init         OF((deflate_state *s));
int  _tr_tally        OF((deflate_state *s, unsigned dist, unsigned lc));
void _tr_flush_block  OF((deflate_state *s, charf *buf, ulg stored_len,
                          int eof));
void _tr_align        OF((deflate_state *s));
void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
                          int eof));

#define d_code(dist) \
   ((dist) < 256 ? _dist_code[dist] : _dist_code[256+((dist)>>7)])
/* Mapping from a distance to a distance code. dist is the distance - 1 and
 * must not have side effects. _dist_code[256] and _dist_code[257] are never
 * used.
 */

#ifndef DEBUG
/* Inline versions of _tr_tally for speed: */

#if defined(GEN_TREES_H) || !defined(STDC)
  extern uch _length_code[];
  extern uch _dist_code[];
#else
  extern const uch _length_code[];
  extern const uch _dist_code[];
#endif

# define _tr_tally_lit(s, c, flush) \
  { uch cc = (c); \
    s->d_buf[s->last_lit] = 0; \
    s->l_buf[s->last_lit++] = cc; \
    s->dyn_ltree[cc].Freq++; \
    flush = (s->last_lit == s->lit_bufsize-1); \
   }
# define _tr_tally_dist(s, distance, length, flush) \
  { uch len = (length); \
    ush dist = (distance); \
    s->d_buf[s->last_lit] = dist; \
    s->l_buf[s->last_lit++] = len; \
    dist--; \
    s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
    s->dyn_dtree[d_code(dist)].Freq++; \
    flush = (s->last_lit == s->lit_bufsize-1); \
  }
#else
# define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c)
# define _tr_tally_dist(s, distance, length, flush) \
              flush = _tr_tally(s, distance, length)
#endif

#endif /* DEFLATE_H */
1	niro	532	/* 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	niro	815	/* @(#) $Id: deflate.h,v 1.1 2005/02/27 23:15:39 hpa Exp $ */
12	niro	532
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			/* ===========================================================================
27			* Internal compression state.
28			*/
29
30			#define LENGTH_CODES 29
31			/* number of length codes, not counting the special END_BLOCK code */
32
33			#define LITERALS 256
34			/* number of literal bytes 0..255 */
35
36			#define L_CODES (LITERALS+1+LENGTH_CODES)
37			/* number of Literal or Length codes, including the END_BLOCK code */
38
39			#define D_CODES 30
40			/* number of distance codes */
41
42			#define BL_CODES 19
43			/* number of codes used to transfer the bit lengths */
44
45			#define HEAP_SIZE (2*L_CODES+1)
46			/* maximum heap size */
47
48			#define MAX_BITS 15
49			/* All codes must not exceed MAX_BITS bits */
50
51			#define INIT_STATE 42
52			#define EXTRA_STATE 69
53			#define NAME_STATE 73
54			#define COMMENT_STATE 91
55			#define HCRC_STATE 103
56			#define BUSY_STATE 113
57			#define FINISH_STATE 666
58			/* Stream status */
59
60
61			/* Data structure describing a single value and its code string. */
62			typedef struct ct_data_s {
63			union {
64			ush freq; /* frequency count */
65			ush code; /* bit string */
66			} fc;
67			union {
68			ush dad; /* father node in Huffman tree */
69			ush len; /* length of bit string */
70			} dl;
71			} FAR ct_data;
72
73			#define Freq fc.freq
74			#define Code fc.code
75			#define Dad dl.dad
76			#define Len dl.len
77
78			typedef struct static_tree_desc_s static_tree_desc;
79
80			typedef struct tree_desc_s {
81			ct_data dyn_tree; / the dynamic tree */
82			int max_code; /* largest code with non zero frequency */
83			static_tree_desc stat_desc; / the corresponding static tree */
84			} FAR tree_desc;
85
86			typedef ush Pos;
87			typedef Pos FAR Posf;
88			typedef unsigned IPos;
89
90			/* A Pos is an index in the character window. We use short instead of int to
91			* save space in the various tables. IPos is used only for parameter passing.
92			*/
93
94			typedef struct internal_state {
95			z_streamp strm; /* pointer back to this zlib stream */
96			int status; /* as the name implies */
97			Bytef pending_buf; / output still pending */
98			ulg pending_buf_size; /* size of pending_buf */
99			Bytef pending_out; / next pending byte to output to the stream */
100			uInt pending; /* nb of bytes in the pending buffer */
101			int wrap; /* bit 0 true for zlib, bit 1 true for gzip */
102			gz_headerp gzhead; /* gzip header information to write */
103			uInt gzindex; /* where in extra, name, or comment */
104			Byte method; /* STORED (for zip only) or DEFLATED */
105			int last_flush; /* value of flush param for previous deflate call */
106
107			/* used by deflate.c: */
108
109			uInt w_size; /* LZ77 window size (32K by default) */
110			uInt w_bits; /* log2(w_size) (8..16) */
111			uInt w_mask; /* w_size - 1 */
112
113			Bytef *window;
114			/* Sliding window. Input bytes are read into the second half of the window,
115			* and move to the first half later to keep a dictionary of at least wSize
116			* bytes. With this organization, matches are limited to a distance of
117			* wSize-MAX_MATCH bytes, but this ensures that IO is always
118			* performed with a length multiple of the block size. Also, it limits
119			* the window size to 64K, which is quite useful on MSDOS.
120			* To do: use the user input buffer as sliding window.
121			*/
122
123			ulg window_size;
124			/* Actual size of window: 2*wSize, except when the user input buffer
125			* is directly used as sliding window.
126			*/
127
128			Posf *prev;
129			/* Link to older string with same hash index. To limit the size of this
130			* array to 64K, this link is maintained only for the last 32K strings.
131			* An index in this array is thus a window index modulo 32K.
132			*/
133
134			Posf head; / Heads of the hash chains or NIL. */
135
136			uInt ins_h; /* hash index of string to be inserted */
137			uInt hash_size; /* number of elements in hash table */
138			uInt hash_bits; /* log2(hash_size) */
139			uInt hash_mask; /* hash_size-1 */
140
141			uInt hash_shift;
142			/* Number of bits by which ins_h must be shifted at each input
143			* step. It must be such that after MIN_MATCH steps, the oldest
144			* byte no longer takes part in the hash key, that is:
145			* hash_shift * MIN_MATCH >= hash_bits
146			*/
147
148			long block_start;
149			/* Window position at the beginning of the current output block. Gets
150			* negative when the window is moved backwards.
151			*/
152
153			uInt match_length; /* length of best match */
154			IPos prev_match; /* previous match */
155			int match_available; /* set if previous match exists */
156			uInt strstart; /* start of string to insert */
157			uInt match_start; /* start of matching string */
158			uInt lookahead; /* number of valid bytes ahead in window */
159
160			uInt prev_length;
161			/* Length of the best match at previous step. Matches not greater than this
162			* are discarded. This is used in the lazy match evaluation.
163			*/
164
165			uInt max_chain_length;
166			/* To speed up deflation, hash chains are never searched beyond this
167			* length. A higher limit improves compression ratio but degrades the
168			* speed.
169			*/
170
171			uInt max_lazy_match;
172			/* Attempt to find a better match only when the current match is strictly
173			* smaller than this value. This mechanism is used only for compression
174			* levels >= 4.
175			*/
176			# define max_insert_length max_lazy_match
177			/* Insert new strings in the hash table only if the match length is not
178			* greater than this length. This saves time but degrades compression.
179			* max_insert_length is used only for compression levels <= 3.
180			*/
181
182			int level; /* compression level (1..9) */
183			int strategy; /* favor or force Huffman coding*/
184
185			uInt good_match;
186			/* Use a faster search when the previous match is longer than this */
187
188			int nice_match; /* Stop searching when current match exceeds this */
189
190			/* used by trees.c: */
191			/* Didn't use ct_data typedef below to supress compiler warning */
192			struct ct_data_s dyn_ltree[HEAP_SIZE]; /* literal and length tree */
193			struct ct_data_s dyn_dtree[2D_CODES+1]; / distance tree */
194			struct ct_data_s bl_tree[2BL_CODES+1]; / Huffman tree for bit lengths */
195
196			struct tree_desc_s l_desc; /* desc. for literal tree */
197			struct tree_desc_s d_desc; /* desc. for distance tree */
198			struct tree_desc_s bl_desc; /* desc. for bit length tree */
199
200			ush bl_count[MAX_BITS+1];
201			/* number of codes at each bit length for an optimal tree */
202
203			int heap[2L_CODES+1]; / heap used to build the Huffman trees */
204			int heap_len; /* number of elements in the heap */
205			int heap_max; /* element of largest frequency */
206			/* The sons of heap[n] are heap[2n] and heap[2n+1]. heap[0] is not used.
207			* The same heap array is used to build all trees.
208			*/
209
210			uch depth[2*L_CODES+1];
211			/* Depth of each subtree used as tie breaker for trees of equal frequency
212			*/
213
214			uchf l_buf; / buffer for literals or lengths */
215
216			uInt lit_bufsize;
217			/* Size of match buffer for literals/lengths. There are 4 reasons for
218			* limiting lit_bufsize to 64K:
219			* - frequencies can be kept in 16 bit counters
220			* - if compression is not successful for the first block, all input
221			* data is still in the window so we can still emit a stored block even
222			* when input comes from standard input. (This can also be done for
223			* all blocks if lit_bufsize is not greater than 32K.)
224			* - if compression is not successful for a file smaller than 64K, we can
225			* even emit a stored file instead of a stored block (saving 5 bytes).
226			* This is applicable only for zip (not gzip or zlib).
227			* - creating new Huffman trees less frequently may not provide fast
228			* adaptation to changes in the input data statistics. (Take for
229			* example a binary file with poorly compressible code followed by
230			* a highly compressible string table.) Smaller buffer sizes give
231			* fast adaptation but have of course the overhead of transmitting
232			* trees more frequently.
233			* - I can't count above 4
234			*/
235
236			uInt last_lit; /* running index in l_buf */
237
238			ushf *d_buf;
239			/* Buffer for distances. To simplify the code, d_buf and l_buf have
240			* the same number of elements. To use different lengths, an extra flag
241			* array would be necessary.
242			*/
243
244			ulg opt_len; /* bit length of current block with optimal trees */
245			ulg static_len; /* bit length of current block with static trees */
246			uInt matches; /* number of string matches in current block */
247			int last_eob_len; /* bit length of EOB code for last block */
248
249			#ifdef DEBUG
250			ulg compressed_len; /* total bit length of compressed file mod 2^32 */
251			ulg bits_sent; /* bit length of compressed data sent mod 2^32 */
252			#endif
253
254			ush bi_buf;
255			/* Output buffer. bits are inserted starting at the bottom (least
256			* significant bits).
257			*/
258			int bi_valid;
259			/* Number of valid bits in bi_buf. All bits above the last valid bit
260			* are always zero.
261			*/
262
263			} FAR deflate_state;
264
265			/* Output a byte on the stream.
266			* IN assertion: there is enough room in pending_buf.
267			*/
268			#define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
269
270
271			#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
272			/* Minimum amount of lookahead, except at the end of the input file.
273			* See deflate.c for comments about the MIN_MATCH+1.
274			*/
275
276			#define MAX_DIST(s) ((s)->w_size-MIN_LOOKAHEAD)
277			/* In order to simplify the code, particularly on 16 bit machines, match
278			* distances are limited to MAX_DIST instead of WSIZE.
279			*/
280
281			/* in trees.c */
282			void _tr_init OF((deflate_state *s));
283			int _tr_tally OF((deflate_state *s, unsigned dist, unsigned lc));
284			void _tr_flush_block OF((deflate_state s, charf buf, ulg stored_len,
285			int eof));
286			void _tr_align OF((deflate_state *s));
287			void _tr_stored_block OF((deflate_state s, charf buf, ulg stored_len,
288			int eof));
289
290			#define d_code(dist) \
291			((dist) < 256 ? _dist_code[dist] : _dist_code[256+((dist)>>7)])
292			/* Mapping from a distance to a distance code. dist is the distance - 1 and
293			* must not have side effects. _dist_code[256] and _dist_code[257] are never
294			* used.
295			*/
296
297			#ifndef DEBUG
298			/* Inline versions of _tr_tally for speed: */
299
300			#if defined(GEN_TREES_H) \|\| !defined(STDC)
301			extern uch _length_code[];
302			extern uch _dist_code[];
303			#else
304			extern const uch _length_code[];
305			extern const uch _dist_code[];
306			#endif
307
308			# define _tr_tally_lit(s, c, flush) \
309			{ uch cc = (c); \
310			s->d_buf[s->last_lit] = 0; \
311			s->l_buf[s->last_lit++] = cc; \
312			s->dyn_ltree[cc].Freq++; \
313			flush = (s->last_lit == s->lit_bufsize-1); \
314			}
315			# define _tr_tally_dist(s, distance, length, flush) \
316			{ uch len = (length); \
317			ush dist = (distance); \
318			s->d_buf[s->last_lit] = dist; \
319			s->l_buf[s->last_lit++] = len; \
320			dist--; \
321			s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
322			s->dyn_dtree[d_code(dist)].Freq++; \
323			flush = (s->last_lit == s->lit_bufsize-1); \
324			}
325			#else
326			# define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c)
327			# define _tr_tally_dist(s, distance, length, flush) \
328			flush = _tr_tally(s, distance, length)
329			#endif
330
331			#endif /* DEFLATE_H */