1e9a128d8SLei Wen /* trees.c -- output deflated data using Huffman coding
2e9a128d8SLei Wen * Copyright (C) 1995-2010 Jean-loup Gailly
3e9a128d8SLei Wen * detect_data_type() function provided freely by Cosmin Truta, 2006
4e9a128d8SLei Wen * For conditions of distribution and use, see copyright notice in zlib.h
5e9a128d8SLei Wen */
6e9a128d8SLei Wen
7e9a128d8SLei Wen /*
8e9a128d8SLei Wen * ALGORITHM
9e9a128d8SLei Wen *
10e9a128d8SLei Wen * The "deflation" process uses several Huffman trees. The more
11e9a128d8SLei Wen * common source values are represented by shorter bit sequences.
12e9a128d8SLei Wen *
13e9a128d8SLei Wen * Each code tree is stored in a compressed form which is itself
14e9a128d8SLei Wen * a Huffman encoding of the lengths of all the code strings (in
15e9a128d8SLei Wen * ascending order by source values). The actual code strings are
16e9a128d8SLei Wen * reconstructed from the lengths in the inflate process, as described
17e9a128d8SLei Wen * in the deflate specification.
18e9a128d8SLei Wen *
19e9a128d8SLei Wen * REFERENCES
20e9a128d8SLei Wen *
21e9a128d8SLei Wen * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
22e9a128d8SLei Wen * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
23e9a128d8SLei Wen *
24e9a128d8SLei Wen * Storer, James A.
25e9a128d8SLei Wen * Data Compression: Methods and Theory, pp. 49-50.
26e9a128d8SLei Wen * Computer Science Press, 1988. ISBN 0-7167-8156-5.
27e9a128d8SLei Wen *
28e9a128d8SLei Wen * Sedgewick, R.
29e9a128d8SLei Wen * Algorithms, p290.
30e9a128d8SLei Wen * Addison-Wesley, 1983. ISBN 0-201-06672-6.
31e9a128d8SLei Wen */
32e9a128d8SLei Wen
33e9a128d8SLei Wen /* @(#) $Id$ */
34e9a128d8SLei Wen
35e9a128d8SLei Wen /* #define GEN_TREES_H */
36e9a128d8SLei Wen
37e9a128d8SLei Wen #include "deflate.h"
38e9a128d8SLei Wen
39e9a128d8SLei Wen #ifdef DEBUG
40e9a128d8SLei Wen # include <ctype.h>
41e9a128d8SLei Wen #endif
42e9a128d8SLei Wen
43e9a128d8SLei Wen /* ===========================================================================
44e9a128d8SLei Wen * Constants
45e9a128d8SLei Wen */
46e9a128d8SLei Wen
47e9a128d8SLei Wen #define MAX_BL_BITS 7
48e9a128d8SLei Wen /* Bit length codes must not exceed MAX_BL_BITS bits */
49e9a128d8SLei Wen
50e9a128d8SLei Wen #define END_BLOCK 256
51e9a128d8SLei Wen /* end of block literal code */
52e9a128d8SLei Wen
53e9a128d8SLei Wen #define REP_3_6 16
54e9a128d8SLei Wen /* repeat previous bit length 3-6 times (2 bits of repeat count) */
55e9a128d8SLei Wen
56e9a128d8SLei Wen #define REPZ_3_10 17
57e9a128d8SLei Wen /* repeat a zero length 3-10 times (3 bits of repeat count) */
58e9a128d8SLei Wen
59e9a128d8SLei Wen #define REPZ_11_138 18
60e9a128d8SLei Wen /* repeat a zero length 11-138 times (7 bits of repeat count) */
61e9a128d8SLei Wen
62e9a128d8SLei Wen local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
63e9a128d8SLei Wen = {0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0};
64e9a128d8SLei Wen
65e9a128d8SLei Wen local const int extra_dbits[D_CODES] /* extra bits for each distance code */
66e9a128d8SLei Wen = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};
67e9a128d8SLei Wen
68e9a128d8SLei Wen local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
69e9a128d8SLei Wen = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
70e9a128d8SLei Wen
71e9a128d8SLei Wen local const uch bl_order[BL_CODES]
72e9a128d8SLei Wen = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
73e9a128d8SLei Wen /* The lengths of the bit length codes are sent in order of decreasing
74e9a128d8SLei Wen * probability, to avoid transmitting the lengths for unused bit length codes.
75e9a128d8SLei Wen */
76e9a128d8SLei Wen
77e9a128d8SLei Wen #define Buf_size (8 * 2*sizeof(char))
78e9a128d8SLei Wen /* Number of bits used within bi_buf. (bi_buf might be implemented on
79e9a128d8SLei Wen * more than 16 bits on some systems.)
80e9a128d8SLei Wen */
81e9a128d8SLei Wen
82e9a128d8SLei Wen /* ===========================================================================
83e9a128d8SLei Wen * Local data. These are initialized only once.
84e9a128d8SLei Wen */
85e9a128d8SLei Wen
86e9a128d8SLei Wen #define DIST_CODE_LEN 512 /* see definition of array dist_code below */
87e9a128d8SLei Wen
88e9a128d8SLei Wen #if defined(GEN_TREES_H) || !defined(STDC)
89e9a128d8SLei Wen /* non ANSI compilers may not accept trees.h */
90e9a128d8SLei Wen
91e9a128d8SLei Wen local ct_data static_ltree[L_CODES+2];
92e9a128d8SLei Wen /* The static literal tree. Since the bit lengths are imposed, there is no
93e9a128d8SLei Wen * need for the L_CODES extra codes used during heap construction. However
94e9a128d8SLei Wen * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
95e9a128d8SLei Wen * below).
96e9a128d8SLei Wen */
97e9a128d8SLei Wen
98e9a128d8SLei Wen local ct_data static_dtree[D_CODES];
99e9a128d8SLei Wen /* The static distance tree. (Actually a trivial tree since all codes use
100e9a128d8SLei Wen * 5 bits.)
101e9a128d8SLei Wen */
102e9a128d8SLei Wen
103e9a128d8SLei Wen uch _dist_code[DIST_CODE_LEN];
104e9a128d8SLei Wen /* Distance codes. The first 256 values correspond to the distances
105e9a128d8SLei Wen * 3 .. 258, the last 256 values correspond to the top 8 bits of
106e9a128d8SLei Wen * the 15 bit distances.
107e9a128d8SLei Wen */
108e9a128d8SLei Wen
109e9a128d8SLei Wen uch _length_code[MAX_MATCH-MIN_MATCH+1];
110e9a128d8SLei Wen /* length code for each normalized match length (0 == MIN_MATCH) */
111e9a128d8SLei Wen
112e9a128d8SLei Wen local int base_length[LENGTH_CODES];
113e9a128d8SLei Wen /* First normalized length for each code (0 = MIN_MATCH) */
114e9a128d8SLei Wen
115e9a128d8SLei Wen local int base_dist[D_CODES];
116e9a128d8SLei Wen /* First normalized distance for each code (0 = distance of 1) */
117e9a128d8SLei Wen
118e9a128d8SLei Wen #else
119e9a128d8SLei Wen # include "trees.h"
120e9a128d8SLei Wen #endif /* GEN_TREES_H */
121e9a128d8SLei Wen
122e9a128d8SLei Wen struct static_tree_desc_s {
123e9a128d8SLei Wen const ct_data *static_tree; /* static tree or NULL */
124e9a128d8SLei Wen const intf *extra_bits; /* extra bits for each code or NULL */
125e9a128d8SLei Wen int extra_base; /* base index for extra_bits */
126e9a128d8SLei Wen int elems; /* max number of elements in the tree */
127e9a128d8SLei Wen int max_length; /* max bit length for the codes */
128e9a128d8SLei Wen };
129e9a128d8SLei Wen
130e9a128d8SLei Wen local static_tree_desc static_l_desc =
131e9a128d8SLei Wen {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
132e9a128d8SLei Wen
133e9a128d8SLei Wen local static_tree_desc static_d_desc =
134e9a128d8SLei Wen {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
135e9a128d8SLei Wen
136e9a128d8SLei Wen local static_tree_desc static_bl_desc =
137e9a128d8SLei Wen {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
138e9a128d8SLei Wen
139e9a128d8SLei Wen /* ===========================================================================
140e9a128d8SLei Wen * Local (static) routines in this file.
141e9a128d8SLei Wen */
142e9a128d8SLei Wen
143e9a128d8SLei Wen local void tr_static_init OF((void));
144e9a128d8SLei Wen local void init_block OF((deflate_state *s));
145e9a128d8SLei Wen local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
146e9a128d8SLei Wen local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
147e9a128d8SLei Wen local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
148e9a128d8SLei Wen local void build_tree OF((deflate_state *s, tree_desc *desc));
149e9a128d8SLei Wen local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
150e9a128d8SLei Wen local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
151e9a128d8SLei Wen local int build_bl_tree OF((deflate_state *s));
152e9a128d8SLei Wen local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
153e9a128d8SLei Wen int blcodes));
154e9a128d8SLei Wen local void compress_block OF((deflate_state *s, ct_data *ltree,
155e9a128d8SLei Wen ct_data *dtree));
156e9a128d8SLei Wen local int detect_data_type OF((deflate_state *s));
157e9a128d8SLei Wen local unsigned bi_reverse OF((unsigned value, int length));
158e9a128d8SLei Wen local void bi_windup OF((deflate_state *s));
159e9a128d8SLei Wen local void bi_flush OF((deflate_state *s));
160e9a128d8SLei Wen local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
161e9a128d8SLei Wen int header));
162e9a128d8SLei Wen
163e9a128d8SLei Wen #ifdef GEN_TREES_H
164e9a128d8SLei Wen local void gen_trees_header OF((void));
165e9a128d8SLei Wen #endif
166e9a128d8SLei Wen
167e9a128d8SLei Wen #ifndef DEBUG
168e9a128d8SLei Wen # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
169e9a128d8SLei Wen /* Send a code of the given tree. c and tree must not have side effects */
170e9a128d8SLei Wen
171e9a128d8SLei Wen #else /* DEBUG */
172e9a128d8SLei Wen # define send_code(s, c, tree) \
173e9a128d8SLei Wen { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
174e9a128d8SLei Wen send_bits(s, tree[c].Code, tree[c].Len); }
175e9a128d8SLei Wen #endif
176e9a128d8SLei Wen
177e9a128d8SLei Wen /* ===========================================================================
178e9a128d8SLei Wen * Output a short LSB first on the stream.
179e9a128d8SLei Wen * IN assertion: there is enough room in pendingBuf.
180e9a128d8SLei Wen */
181e9a128d8SLei Wen #define put_short(s, w) { \
182e9a128d8SLei Wen put_byte(s, (uch)((w) & 0xff)); \
183e9a128d8SLei Wen put_byte(s, (uch)((ush)(w) >> 8)); \
184e9a128d8SLei Wen }
185e9a128d8SLei Wen
186e9a128d8SLei Wen /* ===========================================================================
187e9a128d8SLei Wen * Send a value on a given number of bits.
188e9a128d8SLei Wen * IN assertion: length <= 16 and value fits in length bits.
189e9a128d8SLei Wen */
190e9a128d8SLei Wen #ifdef DEBUG
191e9a128d8SLei Wen local void send_bits OF((deflate_state *s, int value, int length));
192e9a128d8SLei Wen
send_bits(s,value,length)193e9a128d8SLei Wen local void send_bits(s, value, length)
194e9a128d8SLei Wen deflate_state *s;
195e9a128d8SLei Wen int value; /* value to send */
196e9a128d8SLei Wen int length; /* number of bits */
197e9a128d8SLei Wen {
198e9a128d8SLei Wen Tracevv((stderr," l %2d v %4x ", length, value));
199e9a128d8SLei Wen Assert(length > 0 && length <= 15, "invalid length");
200e9a128d8SLei Wen s->bits_sent += (ulg)length;
201e9a128d8SLei Wen
202e9a128d8SLei Wen /* If not enough room in bi_buf, use (valid) bits from bi_buf and
203e9a128d8SLei Wen * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
204e9a128d8SLei Wen * unused bits in value.
205e9a128d8SLei Wen */
206e9a128d8SLei Wen if (s->bi_valid > (int)Buf_size - length) {
207e9a128d8SLei Wen s->bi_buf |= (ush)value << s->bi_valid;
208e9a128d8SLei Wen put_short(s, s->bi_buf);
209e9a128d8SLei Wen s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
210e9a128d8SLei Wen s->bi_valid += length - Buf_size;
211e9a128d8SLei Wen } else {
212e9a128d8SLei Wen s->bi_buf |= (ush)value << s->bi_valid;
213e9a128d8SLei Wen s->bi_valid += length;
214e9a128d8SLei Wen }
215e9a128d8SLei Wen }
216e9a128d8SLei Wen #else /* !DEBUG */
217e9a128d8SLei Wen
218e9a128d8SLei Wen #define send_bits(s, value, length) \
219e9a128d8SLei Wen { int len = length;\
220e9a128d8SLei Wen if (s->bi_valid > (int)Buf_size - len) {\
221e9a128d8SLei Wen int val = value;\
222e9a128d8SLei Wen s->bi_buf |= (ush)val << s->bi_valid;\
223e9a128d8SLei Wen put_short(s, s->bi_buf);\
224e9a128d8SLei Wen s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
225e9a128d8SLei Wen s->bi_valid += len - Buf_size;\
226e9a128d8SLei Wen } else {\
227e9a128d8SLei Wen s->bi_buf |= (ush)(value) << s->bi_valid;\
228e9a128d8SLei Wen s->bi_valid += len;\
229e9a128d8SLei Wen }\
230e9a128d8SLei Wen }
231e9a128d8SLei Wen #endif /* DEBUG */
232e9a128d8SLei Wen
233e9a128d8SLei Wen
234e9a128d8SLei Wen /* the arguments must not have side effects */
235e9a128d8SLei Wen
236e9a128d8SLei Wen /* ===========================================================================
237e9a128d8SLei Wen * Initialize the various 'constant' tables.
238e9a128d8SLei Wen */
tr_static_init()239e9a128d8SLei Wen local void tr_static_init()
240e9a128d8SLei Wen {
241e9a128d8SLei Wen #if defined(GEN_TREES_H) || !defined(STDC)
242e9a128d8SLei Wen static int static_init_done = 0;
243e9a128d8SLei Wen int n; /* iterates over tree elements */
244e9a128d8SLei Wen int bits; /* bit counter */
245e9a128d8SLei Wen int length; /* length value */
246e9a128d8SLei Wen int code; /* code value */
247e9a128d8SLei Wen int dist; /* distance index */
248e9a128d8SLei Wen ush bl_count[MAX_BITS+1];
249e9a128d8SLei Wen /* number of codes at each bit length for an optimal tree */
250e9a128d8SLei Wen
251e9a128d8SLei Wen if (static_init_done) return;
252e9a128d8SLei Wen
253e9a128d8SLei Wen /* For some embedded targets, global variables are not initialized: */
254e9a128d8SLei Wen #ifdef NO_INIT_GLOBAL_POINTERS
255e9a128d8SLei Wen static_l_desc.static_tree = static_ltree;
256e9a128d8SLei Wen static_l_desc.extra_bits = extra_lbits;
257e9a128d8SLei Wen static_d_desc.static_tree = static_dtree;
258e9a128d8SLei Wen static_d_desc.extra_bits = extra_dbits;
259e9a128d8SLei Wen static_bl_desc.extra_bits = extra_blbits;
260e9a128d8SLei Wen #endif
261e9a128d8SLei Wen
262e9a128d8SLei Wen /* Initialize the mapping length (0..255) -> length code (0..28) */
263e9a128d8SLei Wen length = 0;
264e9a128d8SLei Wen for (code = 0; code < LENGTH_CODES-1; code++) {
265e9a128d8SLei Wen base_length[code] = length;
266e9a128d8SLei Wen for (n = 0; n < (1<<extra_lbits[code]); n++) {
267e9a128d8SLei Wen _length_code[length++] = (uch)code;
268e9a128d8SLei Wen }
269e9a128d8SLei Wen }
270e9a128d8SLei Wen Assert (length == 256, "tr_static_init: length != 256");
271e9a128d8SLei Wen /* Note that the length 255 (match length 258) can be represented
272e9a128d8SLei Wen * in two different ways: code 284 + 5 bits or code 285, so we
273e9a128d8SLei Wen * overwrite length_code[255] to use the best encoding:
274e9a128d8SLei Wen */
275e9a128d8SLei Wen _length_code[length-1] = (uch)code;
276e9a128d8SLei Wen
277e9a128d8SLei Wen /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
278e9a128d8SLei Wen dist = 0;
279e9a128d8SLei Wen for (code = 0 ; code < 16; code++) {
280e9a128d8SLei Wen base_dist[code] = dist;
281e9a128d8SLei Wen for (n = 0; n < (1<<extra_dbits[code]); n++) {
282e9a128d8SLei Wen _dist_code[dist++] = (uch)code;
283e9a128d8SLei Wen }
284e9a128d8SLei Wen }
285e9a128d8SLei Wen Assert (dist == 256, "tr_static_init: dist != 256");
286e9a128d8SLei Wen dist >>= 7; /* from now on, all distances are divided by 128 */
287e9a128d8SLei Wen for ( ; code < D_CODES; code++) {
288e9a128d8SLei Wen base_dist[code] = dist << 7;
289e9a128d8SLei Wen for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
290e9a128d8SLei Wen _dist_code[256 + dist++] = (uch)code;
291e9a128d8SLei Wen }
292e9a128d8SLei Wen }
293e9a128d8SLei Wen Assert (dist == 256, "tr_static_init: 256+dist != 512");
294e9a128d8SLei Wen
295e9a128d8SLei Wen /* Construct the codes of the static literal tree */
296e9a128d8SLei Wen for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
297e9a128d8SLei Wen n = 0;
298e9a128d8SLei Wen while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
299e9a128d8SLei Wen while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
300e9a128d8SLei Wen while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
301e9a128d8SLei Wen while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
302e9a128d8SLei Wen /* Codes 286 and 287 do not exist, but we must include them in the
303e9a128d8SLei Wen * tree construction to get a canonical Huffman tree (longest code
304e9a128d8SLei Wen * all ones)
305e9a128d8SLei Wen */
306e9a128d8SLei Wen gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
307e9a128d8SLei Wen
308e9a128d8SLei Wen /* The static distance tree is trivial: */
309e9a128d8SLei Wen for (n = 0; n < D_CODES; n++) {
310e9a128d8SLei Wen static_dtree[n].Len = 5;
311e9a128d8SLei Wen static_dtree[n].Code = bi_reverse((unsigned)n, 5);
312e9a128d8SLei Wen }
313e9a128d8SLei Wen static_init_done = 1;
314e9a128d8SLei Wen
315e9a128d8SLei Wen # ifdef GEN_TREES_H
316e9a128d8SLei Wen gen_trees_header();
317e9a128d8SLei Wen # endif
318e9a128d8SLei Wen #endif /* defined(GEN_TREES_H) || !defined(STDC) */
319e9a128d8SLei Wen }
320e9a128d8SLei Wen
321e9a128d8SLei Wen /* ===========================================================================
322e9a128d8SLei Wen * Genererate the file trees.h describing the static trees.
323e9a128d8SLei Wen */
324e9a128d8SLei Wen #ifdef GEN_TREES_H
325e9a128d8SLei Wen # ifndef DEBUG
326e9a128d8SLei Wen # include <stdio.h>
327e9a128d8SLei Wen # endif
328e9a128d8SLei Wen
329e9a128d8SLei Wen # define SEPARATOR(i, last, width) \
330e9a128d8SLei Wen ((i) == (last)? "\n};\n\n" : \
331e9a128d8SLei Wen ((i) % (width) == (width)-1 ? ",\n" : ", "))
332e9a128d8SLei Wen
gen_trees_header()333e9a128d8SLei Wen void gen_trees_header()
334e9a128d8SLei Wen {
335e9a128d8SLei Wen FILE *header = fopen("trees.h", "w");
336e9a128d8SLei Wen int i;
337e9a128d8SLei Wen
338e9a128d8SLei Wen Assert (header != NULL, "Can't open trees.h");
339e9a128d8SLei Wen fprintf(header,
340e9a128d8SLei Wen "/* header created automatically with -DGEN_TREES_H */\n\n");
341e9a128d8SLei Wen
342e9a128d8SLei Wen fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
343e9a128d8SLei Wen for (i = 0; i < L_CODES+2; i++) {
344e9a128d8SLei Wen fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
345e9a128d8SLei Wen static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
346e9a128d8SLei Wen }
347e9a128d8SLei Wen
348e9a128d8SLei Wen fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
349e9a128d8SLei Wen for (i = 0; i < D_CODES; i++) {
350e9a128d8SLei Wen fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
351e9a128d8SLei Wen static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
352e9a128d8SLei Wen }
353e9a128d8SLei Wen
354e9a128d8SLei Wen fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n");
355e9a128d8SLei Wen for (i = 0; i < DIST_CODE_LEN; i++) {
356e9a128d8SLei Wen fprintf(header, "%2u%s", _dist_code[i],
357e9a128d8SLei Wen SEPARATOR(i, DIST_CODE_LEN-1, 20));
358e9a128d8SLei Wen }
359e9a128d8SLei Wen
360e9a128d8SLei Wen fprintf(header,
361e9a128d8SLei Wen "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
362e9a128d8SLei Wen for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
363e9a128d8SLei Wen fprintf(header, "%2u%s", _length_code[i],
364e9a128d8SLei Wen SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
365e9a128d8SLei Wen }
366e9a128d8SLei Wen
367e9a128d8SLei Wen fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
368e9a128d8SLei Wen for (i = 0; i < LENGTH_CODES; i++) {
369e9a128d8SLei Wen fprintf(header, "%1u%s", base_length[i],
370e9a128d8SLei Wen SEPARATOR(i, LENGTH_CODES-1, 20));
371e9a128d8SLei Wen }
372e9a128d8SLei Wen
373e9a128d8SLei Wen fprintf(header, "local const int base_dist[D_CODES] = {\n");
374e9a128d8SLei Wen for (i = 0; i < D_CODES; i++) {
375e9a128d8SLei Wen fprintf(header, "%5u%s", base_dist[i],
376e9a128d8SLei Wen SEPARATOR(i, D_CODES-1, 10));
377e9a128d8SLei Wen }
378e9a128d8SLei Wen
379e9a128d8SLei Wen fclose(header);
380e9a128d8SLei Wen }
381e9a128d8SLei Wen #endif /* GEN_TREES_H */
382e9a128d8SLei Wen
383e9a128d8SLei Wen /* ===========================================================================
384e9a128d8SLei Wen * Initialize the tree data structures for a new zlib stream.
385e9a128d8SLei Wen */
_tr_init(s)386e9a128d8SLei Wen void ZLIB_INTERNAL _tr_init(s)
387e9a128d8SLei Wen deflate_state *s;
388e9a128d8SLei Wen {
389e9a128d8SLei Wen tr_static_init();
390e9a128d8SLei Wen
391e9a128d8SLei Wen s->l_desc.dyn_tree = s->dyn_ltree;
392e9a128d8SLei Wen s->l_desc.stat_desc = &static_l_desc;
393e9a128d8SLei Wen
394e9a128d8SLei Wen s->d_desc.dyn_tree = s->dyn_dtree;
395e9a128d8SLei Wen s->d_desc.stat_desc = &static_d_desc;
396e9a128d8SLei Wen
397e9a128d8SLei Wen s->bl_desc.dyn_tree = s->bl_tree;
398e9a128d8SLei Wen s->bl_desc.stat_desc = &static_bl_desc;
399e9a128d8SLei Wen
400e9a128d8SLei Wen s->bi_buf = 0;
401e9a128d8SLei Wen s->bi_valid = 0;
402e9a128d8SLei Wen s->last_eob_len = 8; /* enough lookahead for inflate */
403e9a128d8SLei Wen #ifdef DEBUG
404e9a128d8SLei Wen s->compressed_len = 0L;
405e9a128d8SLei Wen s->bits_sent = 0L;
406e9a128d8SLei Wen #endif
407e9a128d8SLei Wen
408e9a128d8SLei Wen /* Initialize the first block of the first file: */
409e9a128d8SLei Wen init_block(s);
410e9a128d8SLei Wen }
411e9a128d8SLei Wen
412e9a128d8SLei Wen /* ===========================================================================
413e9a128d8SLei Wen * Initialize a new block.
414e9a128d8SLei Wen */
init_block(s)415e9a128d8SLei Wen local void init_block(s)
416e9a128d8SLei Wen deflate_state *s;
417e9a128d8SLei Wen {
418e9a128d8SLei Wen int n; /* iterates over tree elements */
419e9a128d8SLei Wen
420e9a128d8SLei Wen /* Initialize the trees. */
421e9a128d8SLei Wen for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
422e9a128d8SLei Wen for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
423e9a128d8SLei Wen for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
424e9a128d8SLei Wen
425e9a128d8SLei Wen s->dyn_ltree[END_BLOCK].Freq = 1;
426e9a128d8SLei Wen s->opt_len = s->static_len = 0L;
427e9a128d8SLei Wen s->last_lit = s->matches = 0;
428e9a128d8SLei Wen }
429e9a128d8SLei Wen
430e9a128d8SLei Wen #define SMALLEST 1
431e9a128d8SLei Wen /* Index within the heap array of least frequent node in the Huffman tree */
432e9a128d8SLei Wen
433e9a128d8SLei Wen
434e9a128d8SLei Wen /* ===========================================================================
435e9a128d8SLei Wen * Remove the smallest element from the heap and recreate the heap with
436e9a128d8SLei Wen * one less element. Updates heap and heap_len.
437e9a128d8SLei Wen */
438e9a128d8SLei Wen #define pqremove(s, tree, top) \
439e9a128d8SLei Wen {\
440e9a128d8SLei Wen top = s->heap[SMALLEST]; \
441e9a128d8SLei Wen s->heap[SMALLEST] = s->heap[s->heap_len--]; \
442e9a128d8SLei Wen pqdownheap(s, tree, SMALLEST); \
443e9a128d8SLei Wen }
444e9a128d8SLei Wen
445e9a128d8SLei Wen /* ===========================================================================
446e9a128d8SLei Wen * Compares to subtrees, using the tree depth as tie breaker when
447e9a128d8SLei Wen * the subtrees have equal frequency. This minimizes the worst case length.
448e9a128d8SLei Wen */
449e9a128d8SLei Wen #define smaller(tree, n, m, depth) \
450e9a128d8SLei Wen (tree[n].Freq < tree[m].Freq || \
451e9a128d8SLei Wen (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
452e9a128d8SLei Wen
453e9a128d8SLei Wen /* ===========================================================================
454e9a128d8SLei Wen * Restore the heap property by moving down the tree starting at node k,
455e9a128d8SLei Wen * exchanging a node with the smallest of its two sons if necessary, stopping
456e9a128d8SLei Wen * when the heap property is re-established (each father smaller than its
457e9a128d8SLei Wen * two sons).
458e9a128d8SLei Wen */
pqdownheap(s,tree,k)459e9a128d8SLei Wen local void pqdownheap(s, tree, k)
460e9a128d8SLei Wen deflate_state *s;
461e9a128d8SLei Wen ct_data *tree; /* the tree to restore */
462e9a128d8SLei Wen int k; /* node to move down */
463e9a128d8SLei Wen {
464e9a128d8SLei Wen int v = s->heap[k];
465e9a128d8SLei Wen int j = k << 1; /* left son of k */
466e9a128d8SLei Wen while (j <= s->heap_len) {
467e9a128d8SLei Wen /* Set j to the smallest of the two sons: */
468e9a128d8SLei Wen if (j < s->heap_len &&
469e9a128d8SLei Wen smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
470e9a128d8SLei Wen j++;
471e9a128d8SLei Wen }
472e9a128d8SLei Wen /* Exit if v is smaller than both sons */
473e9a128d8SLei Wen if (smaller(tree, v, s->heap[j], s->depth)) break;
474e9a128d8SLei Wen
475e9a128d8SLei Wen /* Exchange v with the smallest son */
476e9a128d8SLei Wen s->heap[k] = s->heap[j]; k = j;
477e9a128d8SLei Wen
478e9a128d8SLei Wen /* And continue down the tree, setting j to the left son of k */
479e9a128d8SLei Wen j <<= 1;
480e9a128d8SLei Wen }
481e9a128d8SLei Wen s->heap[k] = v;
482e9a128d8SLei Wen }
483e9a128d8SLei Wen
484e9a128d8SLei Wen /* ===========================================================================
485e9a128d8SLei Wen * Compute the optimal bit lengths for a tree and update the total bit length
486e9a128d8SLei Wen * for the current block.
487e9a128d8SLei Wen * IN assertion: the fields freq and dad are set, heap[heap_max] and
488e9a128d8SLei Wen * above are the tree nodes sorted by increasing frequency.
489e9a128d8SLei Wen * OUT assertions: the field len is set to the optimal bit length, the
490e9a128d8SLei Wen * array bl_count contains the frequencies for each bit length.
491e9a128d8SLei Wen * The length opt_len is updated; static_len is also updated if stree is
492e9a128d8SLei Wen * not null.
493e9a128d8SLei Wen */
gen_bitlen(s,desc)494e9a128d8SLei Wen local void gen_bitlen(s, desc)
495e9a128d8SLei Wen deflate_state *s;
496e9a128d8SLei Wen tree_desc *desc; /* the tree descriptor */
497e9a128d8SLei Wen {
498e9a128d8SLei Wen ct_data *tree = desc->dyn_tree;
499e9a128d8SLei Wen int max_code = desc->max_code;
500e9a128d8SLei Wen const ct_data *stree = desc->stat_desc->static_tree;
501e9a128d8SLei Wen const intf *extra = desc->stat_desc->extra_bits;
502e9a128d8SLei Wen int base = desc->stat_desc->extra_base;
503e9a128d8SLei Wen int max_length = desc->stat_desc->max_length;
504e9a128d8SLei Wen int h; /* heap index */
505e9a128d8SLei Wen int n, m; /* iterate over the tree elements */
506e9a128d8SLei Wen int bits; /* bit length */
507e9a128d8SLei Wen int xbits; /* extra bits */
508e9a128d8SLei Wen ush f; /* frequency */
509e9a128d8SLei Wen int overflow = 0; /* number of elements with bit length too large */
510e9a128d8SLei Wen
511e9a128d8SLei Wen for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
512e9a128d8SLei Wen
513e9a128d8SLei Wen /* In a first pass, compute the optimal bit lengths (which may
514e9a128d8SLei Wen * overflow in the case of the bit length tree).
515e9a128d8SLei Wen */
516e9a128d8SLei Wen tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
517e9a128d8SLei Wen
518e9a128d8SLei Wen for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
519e9a128d8SLei Wen n = s->heap[h];
520e9a128d8SLei Wen bits = tree[tree[n].Dad].Len + 1;
521e9a128d8SLei Wen if (bits > max_length) bits = max_length, overflow++;
522e9a128d8SLei Wen tree[n].Len = (ush)bits;
523e9a128d8SLei Wen /* We overwrite tree[n].Dad which is no longer needed */
524e9a128d8SLei Wen
525e9a128d8SLei Wen if (n > max_code) continue; /* not a leaf node */
526e9a128d8SLei Wen
527e9a128d8SLei Wen s->bl_count[bits]++;
528e9a128d8SLei Wen xbits = 0;
529e9a128d8SLei Wen if (n >= base) xbits = extra[n-base];
530e9a128d8SLei Wen f = tree[n].Freq;
531e9a128d8SLei Wen s->opt_len += (ulg)f * (bits + xbits);
532e9a128d8SLei Wen if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
533e9a128d8SLei Wen }
534e9a128d8SLei Wen if (overflow == 0) return;
535e9a128d8SLei Wen
536e9a128d8SLei Wen Trace((stderr,"\nbit length overflow\n"));
537e9a128d8SLei Wen /* This happens for example on obj2 and pic of the Calgary corpus */
538e9a128d8SLei Wen
539e9a128d8SLei Wen /* Find the first bit length which could increase: */
540e9a128d8SLei Wen do {
541e9a128d8SLei Wen bits = max_length-1;
542e9a128d8SLei Wen while (s->bl_count[bits] == 0) bits--;
543e9a128d8SLei Wen s->bl_count[bits]--; /* move one leaf down the tree */
544e9a128d8SLei Wen s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
545e9a128d8SLei Wen s->bl_count[max_length]--;
546e9a128d8SLei Wen /* The brother of the overflow item also moves one step up,
547e9a128d8SLei Wen * but this does not affect bl_count[max_length]
548e9a128d8SLei Wen */
549e9a128d8SLei Wen overflow -= 2;
550e9a128d8SLei Wen } while (overflow > 0);
551e9a128d8SLei Wen
552e9a128d8SLei Wen /* Now recompute all bit lengths, scanning in increasing frequency.
553e9a128d8SLei Wen * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
554e9a128d8SLei Wen * lengths instead of fixing only the wrong ones. This idea is taken
555e9a128d8SLei Wen * from 'ar' written by Haruhiko Okumura.)
556e9a128d8SLei Wen */
557e9a128d8SLei Wen for (bits = max_length; bits != 0; bits--) {
558e9a128d8SLei Wen n = s->bl_count[bits];
559e9a128d8SLei Wen while (n != 0) {
560e9a128d8SLei Wen m = s->heap[--h];
561e9a128d8SLei Wen if (m > max_code) continue;
562e9a128d8SLei Wen if ((unsigned) tree[m].Len != (unsigned) bits) {
563e9a128d8SLei Wen Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
564e9a128d8SLei Wen s->opt_len += ((long)bits - (long)tree[m].Len)
565e9a128d8SLei Wen *(long)tree[m].Freq;
566e9a128d8SLei Wen tree[m].Len = (ush)bits;
567e9a128d8SLei Wen }
568e9a128d8SLei Wen n--;
569e9a128d8SLei Wen }
570e9a128d8SLei Wen }
571e9a128d8SLei Wen }
572e9a128d8SLei Wen
573e9a128d8SLei Wen /* ===========================================================================
574e9a128d8SLei Wen * Generate the codes for a given tree and bit counts (which need not be
575e9a128d8SLei Wen * optimal).
576e9a128d8SLei Wen * IN assertion: the array bl_count contains the bit length statistics for
577e9a128d8SLei Wen * the given tree and the field len is set for all tree elements.
578e9a128d8SLei Wen * OUT assertion: the field code is set for all tree elements of non
579e9a128d8SLei Wen * zero code length.
580e9a128d8SLei Wen */
gen_codes(tree,max_code,bl_count)581e9a128d8SLei Wen local void gen_codes (tree, max_code, bl_count)
582e9a128d8SLei Wen ct_data *tree; /* the tree to decorate */
583e9a128d8SLei Wen int max_code; /* largest code with non zero frequency */
584e9a128d8SLei Wen ushf *bl_count; /* number of codes at each bit length */
585e9a128d8SLei Wen {
586e9a128d8SLei Wen ush next_code[MAX_BITS+1]; /* next code value for each bit length */
587e9a128d8SLei Wen ush code = 0; /* running code value */
588e9a128d8SLei Wen int bits; /* bit index */
589e9a128d8SLei Wen int n; /* code index */
590e9a128d8SLei Wen
591e9a128d8SLei Wen /* The distribution counts are first used to generate the code values
592e9a128d8SLei Wen * without bit reversal.
593e9a128d8SLei Wen */
594e9a128d8SLei Wen for (bits = 1; bits <= MAX_BITS; bits++) {
595e9a128d8SLei Wen next_code[bits] = code = (code + bl_count[bits-1]) << 1;
596e9a128d8SLei Wen }
597e9a128d8SLei Wen /* Check that the bit counts in bl_count are consistent. The last code
598e9a128d8SLei Wen * must be all ones.
599e9a128d8SLei Wen */
600e9a128d8SLei Wen Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
601e9a128d8SLei Wen "inconsistent bit counts");
602e9a128d8SLei Wen Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
603e9a128d8SLei Wen
604e9a128d8SLei Wen for (n = 0; n <= max_code; n++) {
605e9a128d8SLei Wen int len = tree[n].Len;
606e9a128d8SLei Wen if (len == 0) continue;
607e9a128d8SLei Wen /* Now reverse the bits */
608e9a128d8SLei Wen tree[n].Code = bi_reverse(next_code[len]++, len);
609e9a128d8SLei Wen
610e9a128d8SLei Wen Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
611e9a128d8SLei Wen n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
612e9a128d8SLei Wen }
613e9a128d8SLei Wen }
614e9a128d8SLei Wen
615e9a128d8SLei Wen /* ===========================================================================
616e9a128d8SLei Wen * Construct one Huffman tree and assigns the code bit strings and lengths.
617e9a128d8SLei Wen * Update the total bit length for the current block.
618e9a128d8SLei Wen * IN assertion: the field freq is set for all tree elements.
619e9a128d8SLei Wen * OUT assertions: the fields len and code are set to the optimal bit length
620e9a128d8SLei Wen * and corresponding code. The length opt_len is updated; static_len is
621e9a128d8SLei Wen * also updated if stree is not null. The field max_code is set.
622e9a128d8SLei Wen */
build_tree(s,desc)623e9a128d8SLei Wen local void build_tree(s, desc)
624e9a128d8SLei Wen deflate_state *s;
625e9a128d8SLei Wen tree_desc *desc; /* the tree descriptor */
626e9a128d8SLei Wen {
627e9a128d8SLei Wen ct_data *tree = desc->dyn_tree;
628e9a128d8SLei Wen const ct_data *stree = desc->stat_desc->static_tree;
629e9a128d8SLei Wen int elems = desc->stat_desc->elems;
630e9a128d8SLei Wen int n, m; /* iterate over heap elements */
631e9a128d8SLei Wen int max_code = -1; /* largest code with non zero frequency */
632e9a128d8SLei Wen int node; /* new node being created */
633e9a128d8SLei Wen
634e9a128d8SLei Wen /* Construct the initial heap, with least frequent element in
635e9a128d8SLei Wen * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
636e9a128d8SLei Wen * heap[0] is not used.
637e9a128d8SLei Wen */
638e9a128d8SLei Wen s->heap_len = 0, s->heap_max = HEAP_SIZE;
639e9a128d8SLei Wen
640e9a128d8SLei Wen for (n = 0; n < elems; n++) {
641e9a128d8SLei Wen if (tree[n].Freq != 0) {
642e9a128d8SLei Wen s->heap[++(s->heap_len)] = max_code = n;
643e9a128d8SLei Wen s->depth[n] = 0;
644e9a128d8SLei Wen } else {
645e9a128d8SLei Wen tree[n].Len = 0;
646e9a128d8SLei Wen }
647e9a128d8SLei Wen }
648e9a128d8SLei Wen
649e9a128d8SLei Wen /* The pkzip format requires that at least one distance code exists,
650e9a128d8SLei Wen * and that at least one bit should be sent even if there is only one
651e9a128d8SLei Wen * possible code. So to avoid special checks later on we force at least
652e9a128d8SLei Wen * two codes of non zero frequency.
653e9a128d8SLei Wen */
654e9a128d8SLei Wen while (s->heap_len < 2) {
655e9a128d8SLei Wen node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
656e9a128d8SLei Wen tree[node].Freq = 1;
657e9a128d8SLei Wen s->depth[node] = 0;
658e9a128d8SLei Wen s->opt_len--; if (stree) s->static_len -= stree[node].Len;
659e9a128d8SLei Wen /* node is 0 or 1 so it does not have extra bits */
660e9a128d8SLei Wen }
661e9a128d8SLei Wen desc->max_code = max_code;
662e9a128d8SLei Wen
663e9a128d8SLei Wen /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
664e9a128d8SLei Wen * establish sub-heaps of increasing lengths:
665e9a128d8SLei Wen */
666e9a128d8SLei Wen for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
667e9a128d8SLei Wen
668e9a128d8SLei Wen /* Construct the Huffman tree by repeatedly combining the least two
669e9a128d8SLei Wen * frequent nodes.
670e9a128d8SLei Wen */
671e9a128d8SLei Wen node = elems; /* next internal node of the tree */
672e9a128d8SLei Wen do {
673e9a128d8SLei Wen pqremove(s, tree, n); /* n = node of least frequency */
674e9a128d8SLei Wen m = s->heap[SMALLEST]; /* m = node of next least frequency */
675e9a128d8SLei Wen
676e9a128d8SLei Wen s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
677e9a128d8SLei Wen s->heap[--(s->heap_max)] = m;
678e9a128d8SLei Wen
679e9a128d8SLei Wen /* Create a new node father of n and m */
680e9a128d8SLei Wen tree[node].Freq = tree[n].Freq + tree[m].Freq;
681e9a128d8SLei Wen s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
682e9a128d8SLei Wen s->depth[n] : s->depth[m]) + 1);
683e9a128d8SLei Wen tree[n].Dad = tree[m].Dad = (ush)node;
684e9a128d8SLei Wen #ifdef DUMP_BL_TREE
685e9a128d8SLei Wen if (tree == s->bl_tree) {
686e9a128d8SLei Wen fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
687e9a128d8SLei Wen node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
688e9a128d8SLei Wen }
689e9a128d8SLei Wen #endif
690e9a128d8SLei Wen /* and insert the new node in the heap */
691e9a128d8SLei Wen s->heap[SMALLEST] = node++;
692e9a128d8SLei Wen pqdownheap(s, tree, SMALLEST);
693e9a128d8SLei Wen
694e9a128d8SLei Wen } while (s->heap_len >= 2);
695e9a128d8SLei Wen
696e9a128d8SLei Wen s->heap[--(s->heap_max)] = s->heap[SMALLEST];
697e9a128d8SLei Wen
698e9a128d8SLei Wen /* At this point, the fields freq and dad are set. We can now
699e9a128d8SLei Wen * generate the bit lengths.
700e9a128d8SLei Wen */
701e9a128d8SLei Wen gen_bitlen(s, (tree_desc *)desc);
702e9a128d8SLei Wen
703e9a128d8SLei Wen /* The field len is now set, we can generate the bit codes */
704e9a128d8SLei Wen gen_codes ((ct_data *)tree, max_code, s->bl_count);
705e9a128d8SLei Wen }
706e9a128d8SLei Wen
707e9a128d8SLei Wen /* ===========================================================================
708e9a128d8SLei Wen * Scan a literal or distance tree to determine the frequencies of the codes
709e9a128d8SLei Wen * in the bit length tree.
710e9a128d8SLei Wen */
scan_tree(s,tree,max_code)711e9a128d8SLei Wen local void scan_tree (s, tree, max_code)
712e9a128d8SLei Wen deflate_state *s;
713e9a128d8SLei Wen ct_data *tree; /* the tree to be scanned */
714e9a128d8SLei Wen int max_code; /* and its largest code of non zero frequency */
715e9a128d8SLei Wen {
716e9a128d8SLei Wen int n; /* iterates over all tree elements */
717e9a128d8SLei Wen int prevlen = -1; /* last emitted length */
718e9a128d8SLei Wen int curlen; /* length of current code */
719e9a128d8SLei Wen int nextlen = tree[0].Len; /* length of next code */
720e9a128d8SLei Wen int count = 0; /* repeat count of the current code */
721e9a128d8SLei Wen int max_count = 7; /* max repeat count */
722e9a128d8SLei Wen int min_count = 4; /* min repeat count */
723e9a128d8SLei Wen
724e9a128d8SLei Wen if (nextlen == 0) max_count = 138, min_count = 3;
725e9a128d8SLei Wen tree[max_code+1].Len = (ush)0xffff; /* guard */
726e9a128d8SLei Wen
727e9a128d8SLei Wen for (n = 0; n <= max_code; n++) {
728e9a128d8SLei Wen curlen = nextlen; nextlen = tree[n+1].Len;
729e9a128d8SLei Wen if (++count < max_count && curlen == nextlen) {
730e9a128d8SLei Wen continue;
731e9a128d8SLei Wen } else if (count < min_count) {
732e9a128d8SLei Wen s->bl_tree[curlen].Freq += count;
733e9a128d8SLei Wen } else if (curlen != 0) {
734e9a128d8SLei Wen if (curlen != prevlen) s->bl_tree[curlen].Freq++;
735e9a128d8SLei Wen s->bl_tree[REP_3_6].Freq++;
736e9a128d8SLei Wen } else if (count <= 10) {
737e9a128d8SLei Wen s->bl_tree[REPZ_3_10].Freq++;
738e9a128d8SLei Wen } else {
739e9a128d8SLei Wen s->bl_tree[REPZ_11_138].Freq++;
740e9a128d8SLei Wen }
741e9a128d8SLei Wen count = 0; prevlen = curlen;
742e9a128d8SLei Wen if (nextlen == 0) {
743e9a128d8SLei Wen max_count = 138, min_count = 3;
744e9a128d8SLei Wen } else if (curlen == nextlen) {
745e9a128d8SLei Wen max_count = 6, min_count = 3;
746e9a128d8SLei Wen } else {
747e9a128d8SLei Wen max_count = 7, min_count = 4;
748e9a128d8SLei Wen }
749e9a128d8SLei Wen }
750e9a128d8SLei Wen }
751e9a128d8SLei Wen
752e9a128d8SLei Wen /* ===========================================================================
753e9a128d8SLei Wen * Send a literal or distance tree in compressed form, using the codes in
754e9a128d8SLei Wen * bl_tree.
755e9a128d8SLei Wen */
send_tree(s,tree,max_code)756e9a128d8SLei Wen local void send_tree (s, tree, max_code)
757e9a128d8SLei Wen deflate_state *s;
758e9a128d8SLei Wen ct_data *tree; /* the tree to be scanned */
759e9a128d8SLei Wen int max_code; /* and its largest code of non zero frequency */
760e9a128d8SLei Wen {
761e9a128d8SLei Wen int n; /* iterates over all tree elements */
762e9a128d8SLei Wen int prevlen = -1; /* last emitted length */
763e9a128d8SLei Wen int curlen; /* length of current code */
764e9a128d8SLei Wen int nextlen = tree[0].Len; /* length of next code */
765e9a128d8SLei Wen int count = 0; /* repeat count of the current code */
766e9a128d8SLei Wen int max_count = 7; /* max repeat count */
767e9a128d8SLei Wen int min_count = 4; /* min repeat count */
768e9a128d8SLei Wen
769e9a128d8SLei Wen /* tree[max_code+1].Len = -1; */ /* guard already set */
770e9a128d8SLei Wen if (nextlen == 0) max_count = 138, min_count = 3;
771e9a128d8SLei Wen
772e9a128d8SLei Wen for (n = 0; n <= max_code; n++) {
773e9a128d8SLei Wen curlen = nextlen; nextlen = tree[n+1].Len;
774e9a128d8SLei Wen if (++count < max_count && curlen == nextlen) {
775e9a128d8SLei Wen continue;
776e9a128d8SLei Wen } else if (count < min_count) {
777e9a128d8SLei Wen do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
778e9a128d8SLei Wen
779e9a128d8SLei Wen } else if (curlen != 0) {
780e9a128d8SLei Wen if (curlen != prevlen) {
781e9a128d8SLei Wen send_code(s, curlen, s->bl_tree); count--;
782e9a128d8SLei Wen }
783e9a128d8SLei Wen Assert(count >= 3 && count <= 6, " 3_6?");
784e9a128d8SLei Wen send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
785e9a128d8SLei Wen
786e9a128d8SLei Wen } else if (count <= 10) {
787e9a128d8SLei Wen send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
788e9a128d8SLei Wen
789e9a128d8SLei Wen } else {
790e9a128d8SLei Wen send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
791e9a128d8SLei Wen }
792e9a128d8SLei Wen count = 0; prevlen = curlen;
793e9a128d8SLei Wen if (nextlen == 0) {
794e9a128d8SLei Wen max_count = 138, min_count = 3;
795e9a128d8SLei Wen } else if (curlen == nextlen) {
796e9a128d8SLei Wen max_count = 6, min_count = 3;
797e9a128d8SLei Wen } else {
798e9a128d8SLei Wen max_count = 7, min_count = 4;
799e9a128d8SLei Wen }
800e9a128d8SLei Wen }
801e9a128d8SLei Wen }
802e9a128d8SLei Wen
803e9a128d8SLei Wen /* ===========================================================================
804e9a128d8SLei Wen * Construct the Huffman tree for the bit lengths and return the index in
805e9a128d8SLei Wen * bl_order of the last bit length code to send.
806e9a128d8SLei Wen */
build_bl_tree(s)807e9a128d8SLei Wen local int build_bl_tree(s)
808e9a128d8SLei Wen deflate_state *s;
809e9a128d8SLei Wen {
810e9a128d8SLei Wen int max_blindex; /* index of last bit length code of non zero freq */
811e9a128d8SLei Wen
812e9a128d8SLei Wen /* Determine the bit length frequencies for literal and distance trees */
813e9a128d8SLei Wen scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
814e9a128d8SLei Wen scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
815e9a128d8SLei Wen
816e9a128d8SLei Wen /* Build the bit length tree: */
817e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->bl_desc)));
818e9a128d8SLei Wen /* opt_len now includes the length of the tree representations, except
819e9a128d8SLei Wen * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
820e9a128d8SLei Wen */
821e9a128d8SLei Wen
822e9a128d8SLei Wen /* Determine the number of bit length codes to send. The pkzip format
823e9a128d8SLei Wen * requires that at least 4 bit length codes be sent. (appnote.txt says
824e9a128d8SLei Wen * 3 but the actual value used is 4.)
825e9a128d8SLei Wen */
826e9a128d8SLei Wen for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
827e9a128d8SLei Wen if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
828e9a128d8SLei Wen }
829e9a128d8SLei Wen /* Update opt_len to include the bit length tree and counts */
830e9a128d8SLei Wen s->opt_len += 3*(max_blindex+1) + 5+5+4;
831e9a128d8SLei Wen Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
832e9a128d8SLei Wen s->opt_len, s->static_len));
833e9a128d8SLei Wen
834e9a128d8SLei Wen return max_blindex;
835e9a128d8SLei Wen }
836e9a128d8SLei Wen
837e9a128d8SLei Wen /* ===========================================================================
838e9a128d8SLei Wen * Send the header for a block using dynamic Huffman trees: the counts, the
839e9a128d8SLei Wen * lengths of the bit length codes, the literal tree and the distance tree.
840e9a128d8SLei Wen * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
841e9a128d8SLei Wen */
send_all_trees(s,lcodes,dcodes,blcodes)842e9a128d8SLei Wen local void send_all_trees(s, lcodes, dcodes, blcodes)
843e9a128d8SLei Wen deflate_state *s;
844e9a128d8SLei Wen int lcodes, dcodes, blcodes; /* number of codes for each tree */
845e9a128d8SLei Wen {
846e9a128d8SLei Wen int rank; /* index in bl_order */
847e9a128d8SLei Wen
848e9a128d8SLei Wen Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
849e9a128d8SLei Wen Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
850e9a128d8SLei Wen "too many codes");
851e9a128d8SLei Wen Tracev((stderr, "\nbl counts: "));
852e9a128d8SLei Wen send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
853e9a128d8SLei Wen send_bits(s, dcodes-1, 5);
854e9a128d8SLei Wen send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
855e9a128d8SLei Wen for (rank = 0; rank < blcodes; rank++) {
856e9a128d8SLei Wen Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
857e9a128d8SLei Wen send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
858e9a128d8SLei Wen }
859e9a128d8SLei Wen Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
860e9a128d8SLei Wen
861e9a128d8SLei Wen send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
862e9a128d8SLei Wen Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
863e9a128d8SLei Wen
864e9a128d8SLei Wen send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
865e9a128d8SLei Wen Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
866e9a128d8SLei Wen }
867e9a128d8SLei Wen
868e9a128d8SLei Wen /* ===========================================================================
869e9a128d8SLei Wen * Send a stored block
870e9a128d8SLei Wen */
_tr_stored_block(s,buf,stored_len,last)871e9a128d8SLei Wen void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)
872e9a128d8SLei Wen deflate_state *s;
873e9a128d8SLei Wen charf *buf; /* input block */
874e9a128d8SLei Wen ulg stored_len; /* length of input block */
875e9a128d8SLei Wen int last; /* one if this is the last block for a file */
876e9a128d8SLei Wen {
877e9a128d8SLei Wen send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */
878e9a128d8SLei Wen #ifdef DEBUG
879e9a128d8SLei Wen s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
880e9a128d8SLei Wen s->compressed_len += (stored_len + 4) << 3;
881e9a128d8SLei Wen #endif
882e9a128d8SLei Wen copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
883e9a128d8SLei Wen }
884e9a128d8SLei Wen
885e9a128d8SLei Wen /* ===========================================================================
886e9a128d8SLei Wen * Send one empty static block to give enough lookahead for inflate.
887e9a128d8SLei Wen * This takes 10 bits, of which 7 may remain in the bit buffer.
888e9a128d8SLei Wen * The current inflate code requires 9 bits of lookahead. If the
889e9a128d8SLei Wen * last two codes for the previous block (real code plus EOB) were coded
890e9a128d8SLei Wen * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
891e9a128d8SLei Wen * the last real code. In this case we send two empty static blocks instead
892e9a128d8SLei Wen * of one. (There are no problems if the previous block is stored or fixed.)
893e9a128d8SLei Wen * To simplify the code, we assume the worst case of last real code encoded
894e9a128d8SLei Wen * on one bit only.
895e9a128d8SLei Wen */
_tr_align(s)896e9a128d8SLei Wen void ZLIB_INTERNAL _tr_align(s)
897e9a128d8SLei Wen deflate_state *s;
898e9a128d8SLei Wen {
899e9a128d8SLei Wen send_bits(s, STATIC_TREES<<1, 3);
900e9a128d8SLei Wen send_code(s, END_BLOCK, static_ltree);
901e9a128d8SLei Wen #ifdef DEBUG
902e9a128d8SLei Wen s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
903e9a128d8SLei Wen #endif
904e9a128d8SLei Wen bi_flush(s);
905e9a128d8SLei Wen /* Of the 10 bits for the empty block, we have already sent
906e9a128d8SLei Wen * (10 - bi_valid) bits. The lookahead for the last real code (before
907e9a128d8SLei Wen * the EOB of the previous block) was thus at least one plus the length
908e9a128d8SLei Wen * of the EOB plus what we have just sent of the empty static block.
909e9a128d8SLei Wen */
910e9a128d8SLei Wen if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
911e9a128d8SLei Wen send_bits(s, STATIC_TREES<<1, 3);
912e9a128d8SLei Wen send_code(s, END_BLOCK, static_ltree);
913e9a128d8SLei Wen #ifdef DEBUG
914e9a128d8SLei Wen s->compressed_len += 10L;
915e9a128d8SLei Wen #endif
916e9a128d8SLei Wen bi_flush(s);
917e9a128d8SLei Wen }
918e9a128d8SLei Wen s->last_eob_len = 7;
919e9a128d8SLei Wen }
920e9a128d8SLei Wen
921e9a128d8SLei Wen /* ===========================================================================
922e9a128d8SLei Wen * Determine the best encoding for the current block: dynamic trees, static
923e9a128d8SLei Wen * trees or store, and output the encoded block to the zip file.
924e9a128d8SLei Wen */
_tr_flush_block(s,buf,stored_len,last)925e9a128d8SLei Wen void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
926e9a128d8SLei Wen deflate_state *s;
927e9a128d8SLei Wen charf *buf; /* input block, or NULL if too old */
928e9a128d8SLei Wen ulg stored_len; /* length of input block */
929e9a128d8SLei Wen int last; /* one if this is the last block for a file */
930e9a128d8SLei Wen {
931e9a128d8SLei Wen ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
932e9a128d8SLei Wen int max_blindex = 0; /* index of last bit length code of non zero freq */
933e9a128d8SLei Wen
934e9a128d8SLei Wen /* Build the Huffman trees unless a stored block is forced */
935e9a128d8SLei Wen if (s->level > 0) {
936e9a128d8SLei Wen
937e9a128d8SLei Wen /* Check if the file is binary or text */
938e9a128d8SLei Wen if (s->strm->data_type == Z_UNKNOWN)
939e9a128d8SLei Wen s->strm->data_type = detect_data_type(s);
940e9a128d8SLei Wen
941e9a128d8SLei Wen /* Construct the literal and distance trees */
942e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->l_desc)));
943e9a128d8SLei Wen Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
944e9a128d8SLei Wen s->static_len));
945e9a128d8SLei Wen
946e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->d_desc)));
947e9a128d8SLei Wen Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
948e9a128d8SLei Wen s->static_len));
949e9a128d8SLei Wen /* At this point, opt_len and static_len are the total bit lengths of
950e9a128d8SLei Wen * the compressed block data, excluding the tree representations.
951e9a128d8SLei Wen */
952e9a128d8SLei Wen
953e9a128d8SLei Wen /* Build the bit length tree for the above two trees, and get the index
954e9a128d8SLei Wen * in bl_order of the last bit length code to send.
955e9a128d8SLei Wen */
956e9a128d8SLei Wen max_blindex = build_bl_tree(s);
957e9a128d8SLei Wen
958e9a128d8SLei Wen /* Determine the best encoding. Compute the block lengths in bytes. */
959e9a128d8SLei Wen opt_lenb = (s->opt_len+3+7)>>3;
960e9a128d8SLei Wen static_lenb = (s->static_len+3+7)>>3;
961e9a128d8SLei Wen
962e9a128d8SLei Wen Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
963e9a128d8SLei Wen opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
964e9a128d8SLei Wen s->last_lit));
965e9a128d8SLei Wen
966e9a128d8SLei Wen if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
967e9a128d8SLei Wen
968e9a128d8SLei Wen } else {
969e9a128d8SLei Wen Assert(buf != (char*)0, "lost buf");
970e9a128d8SLei Wen opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
971e9a128d8SLei Wen }
972e9a128d8SLei Wen
973e9a128d8SLei Wen #ifdef FORCE_STORED
974e9a128d8SLei Wen if (buf != (char*)0) { /* force stored block */
975e9a128d8SLei Wen #else
976e9a128d8SLei Wen if (stored_len+4 <= opt_lenb && buf != (char*)0) {
977e9a128d8SLei Wen /* 4: two words for the lengths */
978e9a128d8SLei Wen #endif
979e9a128d8SLei Wen /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
980e9a128d8SLei Wen * Otherwise we can't have processed more than WSIZE input bytes since
981e9a128d8SLei Wen * the last block flush, because compression would have been
982e9a128d8SLei Wen * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
983e9a128d8SLei Wen * transform a block into a stored block.
984e9a128d8SLei Wen */
985e9a128d8SLei Wen _tr_stored_block(s, buf, stored_len, last);
986e9a128d8SLei Wen
987e9a128d8SLei Wen #ifdef FORCE_STATIC
988e9a128d8SLei Wen } else if (static_lenb >= 0) { /* force static trees */
989e9a128d8SLei Wen #else
990e9a128d8SLei Wen } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
991e9a128d8SLei Wen #endif
992e9a128d8SLei Wen send_bits(s, (STATIC_TREES<<1)+last, 3);
993e9a128d8SLei Wen compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
994e9a128d8SLei Wen #ifdef DEBUG
995e9a128d8SLei Wen s->compressed_len += 3 + s->static_len;
996e9a128d8SLei Wen #endif
997e9a128d8SLei Wen } else {
998e9a128d8SLei Wen send_bits(s, (DYN_TREES<<1)+last, 3);
999e9a128d8SLei Wen send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
1000e9a128d8SLei Wen max_blindex+1);
1001e9a128d8SLei Wen compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
1002e9a128d8SLei Wen #ifdef DEBUG
1003e9a128d8SLei Wen s->compressed_len += 3 + s->opt_len;
1004e9a128d8SLei Wen #endif
1005e9a128d8SLei Wen }
1006e9a128d8SLei Wen Assert (s->compressed_len == s->bits_sent, "bad compressed size");
1007e9a128d8SLei Wen /* The above check is made mod 2^32, for files larger than 512 MB
1008e9a128d8SLei Wen * and uLong implemented on 32 bits.
1009e9a128d8SLei Wen */
1010e9a128d8SLei Wen init_block(s);
1011e9a128d8SLei Wen
1012e9a128d8SLei Wen if (last) {
1013e9a128d8SLei Wen bi_windup(s);
1014e9a128d8SLei Wen #ifdef DEBUG
1015e9a128d8SLei Wen s->compressed_len += 7; /* align on byte boundary */
1016e9a128d8SLei Wen #endif
1017e9a128d8SLei Wen }
1018e9a128d8SLei Wen Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
1019e9a128d8SLei Wen s->compressed_len-7*last));
1020e9a128d8SLei Wen }
1021e9a128d8SLei Wen
1022e9a128d8SLei Wen /* ===========================================================================
1023e9a128d8SLei Wen * Save the match info and tally the frequency counts. Return true if
1024e9a128d8SLei Wen * the current block must be flushed.
1025e9a128d8SLei Wen */
_tr_tally(s,dist,lc)1026e9a128d8SLei Wen int ZLIB_INTERNAL _tr_tally (s, dist, lc)
1027e9a128d8SLei Wen deflate_state *s;
1028e9a128d8SLei Wen unsigned dist; /* distance of matched string */
1029e9a128d8SLei Wen unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
1030e9a128d8SLei Wen {
1031e9a128d8SLei Wen s->d_buf[s->last_lit] = (ush)dist;
1032e9a128d8SLei Wen s->l_buf[s->last_lit++] = (uch)lc;
1033e9a128d8SLei Wen if (dist == 0) {
1034e9a128d8SLei Wen /* lc is the unmatched char */
1035e9a128d8SLei Wen s->dyn_ltree[lc].Freq++;
1036e9a128d8SLei Wen } else {
1037e9a128d8SLei Wen s->matches++;
1038e9a128d8SLei Wen /* Here, lc is the match length - MIN_MATCH */
1039e9a128d8SLei Wen dist--; /* dist = match distance - 1 */
1040e9a128d8SLei Wen Assert((ush)dist < (ush)MAX_DIST(s) &&
1041e9a128d8SLei Wen (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
1042e9a128d8SLei Wen (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
1043e9a128d8SLei Wen
1044e9a128d8SLei Wen s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
1045e9a128d8SLei Wen s->dyn_dtree[d_code(dist)].Freq++;
1046e9a128d8SLei Wen }
1047e9a128d8SLei Wen
1048e9a128d8SLei Wen #ifdef TRUNCATE_BLOCK
1049e9a128d8SLei Wen /* Try to guess if it is profitable to stop the current block here */
1050e9a128d8SLei Wen if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
1051e9a128d8SLei Wen /* Compute an upper bound for the compressed length */
1052e9a128d8SLei Wen ulg out_length = (ulg)s->last_lit*8L;
1053e9a128d8SLei Wen ulg in_length = (ulg)((long)s->strstart - s->block_start);
1054e9a128d8SLei Wen int dcode;
1055e9a128d8SLei Wen for (dcode = 0; dcode < D_CODES; dcode++) {
1056e9a128d8SLei Wen out_length += (ulg)s->dyn_dtree[dcode].Freq *
1057e9a128d8SLei Wen (5L+extra_dbits[dcode]);
1058e9a128d8SLei Wen }
1059e9a128d8SLei Wen out_length >>= 3;
1060e9a128d8SLei Wen Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
1061e9a128d8SLei Wen s->last_lit, in_length, out_length,
1062e9a128d8SLei Wen 100L - out_length*100L/in_length));
1063e9a128d8SLei Wen if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
1064e9a128d8SLei Wen }
1065e9a128d8SLei Wen #endif
1066e9a128d8SLei Wen return (s->last_lit == s->lit_bufsize-1);
1067e9a128d8SLei Wen /* We avoid equality with lit_bufsize because of wraparound at 64K
1068e9a128d8SLei Wen * on 16 bit machines and because stored blocks are restricted to
1069e9a128d8SLei Wen * 64K-1 bytes.
1070e9a128d8SLei Wen */
1071e9a128d8SLei Wen }
1072e9a128d8SLei Wen
1073e9a128d8SLei Wen /* ===========================================================================
1074e9a128d8SLei Wen * Send the block data compressed using the given Huffman trees
1075e9a128d8SLei Wen */
compress_block(s,ltree,dtree)1076e9a128d8SLei Wen local void compress_block(s, ltree, dtree)
1077e9a128d8SLei Wen deflate_state *s;
1078e9a128d8SLei Wen ct_data *ltree; /* literal tree */
1079e9a128d8SLei Wen ct_data *dtree; /* distance tree */
1080e9a128d8SLei Wen {
1081e9a128d8SLei Wen unsigned dist; /* distance of matched string */
1082e9a128d8SLei Wen int lc; /* match length or unmatched char (if dist == 0) */
1083e9a128d8SLei Wen unsigned lx = 0; /* running index in l_buf */
1084e9a128d8SLei Wen unsigned code; /* the code to send */
1085e9a128d8SLei Wen int extra; /* number of extra bits to send */
1086e9a128d8SLei Wen
1087e9a128d8SLei Wen if (s->last_lit != 0) do {
1088e9a128d8SLei Wen dist = s->d_buf[lx];
1089e9a128d8SLei Wen lc = s->l_buf[lx++];
1090e9a128d8SLei Wen if (dist == 0) {
1091e9a128d8SLei Wen send_code(s, lc, ltree); /* send a literal byte */
1092e9a128d8SLei Wen Tracecv(isgraph(lc), (stderr," '%c' ", lc));
1093e9a128d8SLei Wen } else {
1094e9a128d8SLei Wen /* Here, lc is the match length - MIN_MATCH */
1095e9a128d8SLei Wen code = _length_code[lc];
1096e9a128d8SLei Wen send_code(s, code+LITERALS+1, ltree); /* send the length code */
1097e9a128d8SLei Wen extra = extra_lbits[code];
1098e9a128d8SLei Wen if (extra != 0) {
1099e9a128d8SLei Wen lc -= base_length[code];
1100e9a128d8SLei Wen send_bits(s, lc, extra); /* send the extra length bits */
1101e9a128d8SLei Wen }
1102e9a128d8SLei Wen dist--; /* dist is now the match distance - 1 */
1103e9a128d8SLei Wen code = d_code(dist);
1104e9a128d8SLei Wen Assert (code < D_CODES, "bad d_code");
1105e9a128d8SLei Wen
1106e9a128d8SLei Wen send_code(s, code, dtree); /* send the distance code */
1107e9a128d8SLei Wen extra = extra_dbits[code];
1108e9a128d8SLei Wen if (extra != 0) {
1109e9a128d8SLei Wen dist -= base_dist[code];
1110e9a128d8SLei Wen send_bits(s, dist, extra); /* send the extra distance bits */
1111e9a128d8SLei Wen }
1112e9a128d8SLei Wen } /* literal or match pair ? */
1113e9a128d8SLei Wen
1114e9a128d8SLei Wen /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
1115e9a128d8SLei Wen Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
1116e9a128d8SLei Wen "pendingBuf overflow");
1117e9a128d8SLei Wen
1118e9a128d8SLei Wen } while (lx < s->last_lit);
1119e9a128d8SLei Wen
1120e9a128d8SLei Wen send_code(s, END_BLOCK, ltree);
1121e9a128d8SLei Wen s->last_eob_len = ltree[END_BLOCK].Len;
1122e9a128d8SLei Wen }
1123e9a128d8SLei Wen
1124e9a128d8SLei Wen /* ===========================================================================
1125e9a128d8SLei Wen * Check if the data type is TEXT or BINARY, using the following algorithm:
1126e9a128d8SLei Wen * - TEXT if the two conditions below are satisfied:
1127e9a128d8SLei Wen * a) There are no non-portable control characters belonging to the
1128e9a128d8SLei Wen * "black list" (0..6, 14..25, 28..31).
1129e9a128d8SLei Wen * b) There is at least one printable character belonging to the
1130e9a128d8SLei Wen * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
1131e9a128d8SLei Wen * - BINARY otherwise.
1132e9a128d8SLei Wen * - The following partially-portable control characters form a
1133e9a128d8SLei Wen * "gray list" that is ignored in this detection algorithm:
1134e9a128d8SLei Wen * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
1135e9a128d8SLei Wen * IN assertion: the fields Freq of dyn_ltree are set.
1136e9a128d8SLei Wen */
detect_data_type(s)1137e9a128d8SLei Wen local int detect_data_type(s)
1138e9a128d8SLei Wen deflate_state *s;
1139e9a128d8SLei Wen {
1140e9a128d8SLei Wen /* black_mask is the bit mask of black-listed bytes
1141e9a128d8SLei Wen * set bits 0..6, 14..25, and 28..31
1142e9a128d8SLei Wen * 0xf3ffc07f = binary 11110011111111111100000001111111
1143e9a128d8SLei Wen */
1144e9a128d8SLei Wen unsigned long black_mask = 0xf3ffc07fUL;
1145e9a128d8SLei Wen int n;
1146e9a128d8SLei Wen
1147e9a128d8SLei Wen /* Check for non-textual ("black-listed") bytes. */
1148e9a128d8SLei Wen for (n = 0; n <= 31; n++, black_mask >>= 1)
1149e9a128d8SLei Wen if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
1150e9a128d8SLei Wen return Z_BINARY;
1151e9a128d8SLei Wen
1152e9a128d8SLei Wen /* Check for textual ("white-listed") bytes. */
1153e9a128d8SLei Wen if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
1154e9a128d8SLei Wen || s->dyn_ltree[13].Freq != 0)
1155e9a128d8SLei Wen return Z_TEXT;
1156e9a128d8SLei Wen for (n = 32; n < LITERALS; n++)
1157e9a128d8SLei Wen if (s->dyn_ltree[n].Freq != 0)
1158e9a128d8SLei Wen return Z_TEXT;
1159e9a128d8SLei Wen
1160e9a128d8SLei Wen /* There are no "black-listed" or "white-listed" bytes:
1161e9a128d8SLei Wen * this stream either is empty or has tolerated ("gray-listed") bytes only.
1162e9a128d8SLei Wen */
1163e9a128d8SLei Wen return Z_BINARY;
1164e9a128d8SLei Wen }
1165e9a128d8SLei Wen
1166e9a128d8SLei Wen /* ===========================================================================
1167e9a128d8SLei Wen * Reverse the first len bits of a code, using straightforward code (a faster
1168e9a128d8SLei Wen * method would use a table)
1169e9a128d8SLei Wen * IN assertion: 1 <= len <= 15
1170e9a128d8SLei Wen */
bi_reverse(value,len)1171*7a32b98dSLei Wen local unsigned bi_reverse(value, len)
1172*7a32b98dSLei Wen unsigned value; /* the value to invert */
1173e9a128d8SLei Wen int len; /* its bit length */
1174e9a128d8SLei Wen {
1175e9a128d8SLei Wen register unsigned res = 0;
1176e9a128d8SLei Wen do {
1177*7a32b98dSLei Wen res |= value & 1;
1178*7a32b98dSLei Wen value >>= 1, res <<= 1;
1179e9a128d8SLei Wen } while (--len > 0);
1180e9a128d8SLei Wen return res >> 1;
1181e9a128d8SLei Wen }
1182e9a128d8SLei Wen
1183e9a128d8SLei Wen /* ===========================================================================
1184e9a128d8SLei Wen * Flush the bit buffer, keeping at most 7 bits in it.
1185e9a128d8SLei Wen */
bi_flush(s)1186e9a128d8SLei Wen local void bi_flush(s)
1187e9a128d8SLei Wen deflate_state *s;
1188e9a128d8SLei Wen {
1189e9a128d8SLei Wen if (s->bi_valid == 16) {
1190e9a128d8SLei Wen put_short(s, s->bi_buf);
1191e9a128d8SLei Wen s->bi_buf = 0;
1192e9a128d8SLei Wen s->bi_valid = 0;
1193e9a128d8SLei Wen } else if (s->bi_valid >= 8) {
1194e9a128d8SLei Wen put_byte(s, (Byte)s->bi_buf);
1195e9a128d8SLei Wen s->bi_buf >>= 8;
1196e9a128d8SLei Wen s->bi_valid -= 8;
1197e9a128d8SLei Wen }
1198e9a128d8SLei Wen }
1199e9a128d8SLei Wen
1200e9a128d8SLei Wen /* ===========================================================================
1201e9a128d8SLei Wen * Flush the bit buffer and align the output on a byte boundary
1202e9a128d8SLei Wen */
bi_windup(s)1203e9a128d8SLei Wen local void bi_windup(s)
1204e9a128d8SLei Wen deflate_state *s;
1205e9a128d8SLei Wen {
1206e9a128d8SLei Wen if (s->bi_valid > 8) {
1207e9a128d8SLei Wen put_short(s, s->bi_buf);
1208e9a128d8SLei Wen } else if (s->bi_valid > 0) {
1209e9a128d8SLei Wen put_byte(s, (Byte)s->bi_buf);
1210e9a128d8SLei Wen }
1211e9a128d8SLei Wen s->bi_buf = 0;
1212e9a128d8SLei Wen s->bi_valid = 0;
1213e9a128d8SLei Wen #ifdef DEBUG
1214e9a128d8SLei Wen s->bits_sent = (s->bits_sent+7) & ~7;
1215e9a128d8SLei Wen #endif
1216e9a128d8SLei Wen }
1217e9a128d8SLei Wen
1218e9a128d8SLei Wen /* ===========================================================================
1219e9a128d8SLei Wen * Copy a stored block, storing first the length and its
1220e9a128d8SLei Wen * one's complement if requested.
1221e9a128d8SLei Wen */
copy_block(s,buf,len,header)1222e9a128d8SLei Wen local void copy_block(s, buf, len, header)
1223e9a128d8SLei Wen deflate_state *s;
1224e9a128d8SLei Wen charf *buf; /* the input data */
1225e9a128d8SLei Wen unsigned len; /* its length */
1226e9a128d8SLei Wen int header; /* true if block header must be written */
1227e9a128d8SLei Wen {
1228e9a128d8SLei Wen bi_windup(s); /* align on byte boundary */
1229e9a128d8SLei Wen s->last_eob_len = 8; /* enough lookahead for inflate */
1230e9a128d8SLei Wen
1231e9a128d8SLei Wen if (header) {
1232e9a128d8SLei Wen put_short(s, (ush)len);
1233e9a128d8SLei Wen put_short(s, (ush)~len);
1234e9a128d8SLei Wen #ifdef DEBUG
1235e9a128d8SLei Wen s->bits_sent += 2*16;
1236e9a128d8SLei Wen #endif
1237e9a128d8SLei Wen }
1238e9a128d8SLei Wen #ifdef DEBUG
1239e9a128d8SLei Wen s->bits_sent += (ulg)len<<3;
1240e9a128d8SLei Wen #endif
1241e9a128d8SLei Wen while (len--) {
1242e9a128d8SLei Wen put_byte(s, *buf++);
1243e9a128d8SLei Wen }
1244e9a128d8SLei Wen }
1245