Contents of /trunk/mkinitrd-magellan/busybox/archival/lzo1x_9x.c
Parent Directory | Revision Log
Revision 1123 -
(show annotations)
(download)
Wed Aug 18 21:56:57 2010 UTC (14 years, 1 month ago) by niro
File MIME type: text/plain
File size: 21043 byte(s)
Wed Aug 18 21:56:57 2010 UTC (14 years, 1 month ago) by niro
File MIME type: text/plain
File size: 21043 byte(s)
-updated to busybox-1.17.1
1 | /* lzo1x_9x.c -- implementation of the LZO1X-999 compression algorithm |
2 | |
3 | This file is part of the LZO real-time data compression library. |
4 | |
5 | Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer |
6 | Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer |
7 | Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer |
8 | Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer |
9 | Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer |
10 | Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer |
11 | Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer |
12 | Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer |
13 | Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer |
14 | Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer |
15 | Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer |
16 | Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer |
17 | Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer |
18 | All Rights Reserved. |
19 | |
20 | The LZO library is free software; you can redistribute it and/or |
21 | modify it under the terms of the GNU General Public License as |
22 | published by the Free Software Foundation; either version 2 of |
23 | the License, or (at your option) any later version. |
24 | |
25 | The LZO library is distributed in the hope that it will be useful, |
26 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
27 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
28 | GNU General Public License for more details. |
29 | |
30 | You should have received a copy of the GNU General Public License |
31 | along with the LZO library; see the file COPYING. |
32 | If not, write to the Free Software Foundation, Inc., |
33 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
34 | |
35 | Markus F.X.J. Oberhumer |
36 | <markus@oberhumer.com> |
37 | http://www.oberhumer.com/opensource/lzo/ |
38 | */ |
39 | #include "libbb.h" |
40 | |
41 | /* The following is probably only safe on Intel-compatible processors ... */ |
42 | #define LZO_UNALIGNED_OK_2 |
43 | #define LZO_UNALIGNED_OK_4 |
44 | |
45 | #include "liblzo.h" |
46 | |
47 | #define LZO_MAX(a,b) ((a) >= (b) ? (a) : (b)) |
48 | #define LZO_MIN(a,b) ((a) <= (b) ? (a) : (b)) |
49 | #define LZO_MAX3(a,b,c) ((a) >= (b) ? LZO_MAX(a,c) : LZO_MAX(b,c)) |
50 | |
51 | /*********************************************************************** |
52 | // |
53 | ************************************************************************/ |
54 | #define SWD_N M4_MAX_OFFSET /* size of ring buffer */ |
55 | #define SWD_F 2048 /* upper limit for match length */ |
56 | |
57 | #define SWD_BEST_OFF (LZO_MAX3(M2_MAX_LEN, M3_MAX_LEN, M4_MAX_LEN) + 1) |
58 | |
59 | typedef struct { |
60 | int init; |
61 | |
62 | unsigned look; /* bytes in lookahead buffer */ |
63 | |
64 | unsigned m_len; |
65 | unsigned m_off; |
66 | |
67 | const uint8_t *bp; |
68 | const uint8_t *ip; |
69 | const uint8_t *in; |
70 | const uint8_t *in_end; |
71 | uint8_t *out; |
72 | |
73 | unsigned r1_lit; |
74 | |
75 | } lzo1x_999_t; |
76 | |
77 | #define getbyte(c) ((c).ip < (c).in_end ? *((c).ip)++ : (-1)) |
78 | |
79 | /* lzo_swd.c -- sliding window dictionary */ |
80 | |
81 | /*********************************************************************** |
82 | // |
83 | ************************************************************************/ |
84 | #define SWD_UINT_MAX USHRT_MAX |
85 | |
86 | #ifndef SWD_HSIZE |
87 | # define SWD_HSIZE 16384 |
88 | #endif |
89 | #ifndef SWD_MAX_CHAIN |
90 | # define SWD_MAX_CHAIN 2048 |
91 | #endif |
92 | |
93 | #define HEAD3(b, p) \ |
94 | ( ((0x9f5f * ((((b[p]<<5)^b[p+1])<<5) ^ b[p+2])) >> 5) & (SWD_HSIZE-1) ) |
95 | |
96 | #if defined(LZO_UNALIGNED_OK_2) |
97 | # define HEAD2(b,p) (* (uint16_t *) &(b[p])) |
98 | #else |
99 | # define HEAD2(b,p) (b[p] ^ ((unsigned)b[p+1]<<8)) |
100 | #endif |
101 | #define NIL2 SWD_UINT_MAX |
102 | |
103 | typedef struct lzo_swd { |
104 | /* public - "built-in" */ |
105 | |
106 | /* public - configuration */ |
107 | unsigned max_chain; |
108 | int use_best_off; |
109 | |
110 | /* public - output */ |
111 | unsigned m_len; |
112 | unsigned m_off; |
113 | unsigned look; |
114 | int b_char; |
115 | #if defined(SWD_BEST_OFF) |
116 | unsigned best_off[SWD_BEST_OFF]; |
117 | #endif |
118 | |
119 | /* semi public */ |
120 | lzo1x_999_t *c; |
121 | unsigned m_pos; |
122 | #if defined(SWD_BEST_OFF) |
123 | unsigned best_pos[SWD_BEST_OFF]; |
124 | #endif |
125 | |
126 | /* private */ |
127 | unsigned ip; /* input pointer (lookahead) */ |
128 | unsigned bp; /* buffer pointer */ |
129 | unsigned rp; /* remove pointer */ |
130 | |
131 | unsigned node_count; |
132 | unsigned first_rp; |
133 | |
134 | uint8_t b[SWD_N + SWD_F]; |
135 | uint8_t b_wrap[SWD_F]; /* must follow b */ |
136 | uint16_t head3[SWD_HSIZE]; |
137 | uint16_t succ3[SWD_N + SWD_F]; |
138 | uint16_t best3[SWD_N + SWD_F]; |
139 | uint16_t llen3[SWD_HSIZE]; |
140 | #ifdef HEAD2 |
141 | uint16_t head2[65536L]; |
142 | #endif |
143 | } lzo_swd_t, *lzo_swd_p; |
144 | |
145 | #define SIZEOF_LZO_SWD_T (sizeof(lzo_swd_t)) |
146 | |
147 | |
148 | /* Access macro for head3. |
149 | * head3[key] may be uninitialized, but then its value will never be used. |
150 | */ |
151 | #define s_get_head3(s,key) s->head3[key] |
152 | |
153 | |
154 | /*********************************************************************** |
155 | // |
156 | ************************************************************************/ |
157 | #define B_SIZE (SWD_N + SWD_F) |
158 | |
159 | static int swd_init(lzo_swd_p s) |
160 | { |
161 | /* defaults */ |
162 | s->node_count = SWD_N; |
163 | |
164 | memset(s->llen3, 0, sizeof(s->llen3[0]) * (unsigned)SWD_HSIZE); |
165 | #ifdef HEAD2 |
166 | memset(s->head2, 0xff, sizeof(s->head2[0]) * 65536L); |
167 | assert(s->head2[0] == NIL2); |
168 | #endif |
169 | |
170 | s->ip = 0; |
171 | s->bp = s->ip; |
172 | s->first_rp = s->ip; |
173 | |
174 | assert(s->ip + SWD_F <= B_SIZE); |
175 | s->look = (unsigned) (s->c->in_end - s->c->ip); |
176 | if (s->look > 0) { |
177 | if (s->look > SWD_F) |
178 | s->look = SWD_F; |
179 | memcpy(&s->b[s->ip], s->c->ip, s->look); |
180 | s->c->ip += s->look; |
181 | s->ip += s->look; |
182 | } |
183 | if (s->ip == B_SIZE) |
184 | s->ip = 0; |
185 | |
186 | s->rp = s->first_rp; |
187 | if (s->rp >= s->node_count) |
188 | s->rp -= s->node_count; |
189 | else |
190 | s->rp += B_SIZE - s->node_count; |
191 | |
192 | return LZO_E_OK; |
193 | } |
194 | |
195 | #define swd_pos2off(s,pos) \ |
196 | (s->bp > (pos) ? s->bp - (pos) : B_SIZE - ((pos) - s->bp)) |
197 | |
198 | |
199 | /*********************************************************************** |
200 | // |
201 | ************************************************************************/ |
202 | static void swd_getbyte(lzo_swd_p s) |
203 | { |
204 | int c; |
205 | |
206 | if ((c = getbyte(*(s->c))) < 0) { |
207 | if (s->look > 0) |
208 | --s->look; |
209 | } else { |
210 | s->b[s->ip] = c; |
211 | if (s->ip < SWD_F) |
212 | s->b_wrap[s->ip] = c; |
213 | } |
214 | if (++s->ip == B_SIZE) |
215 | s->ip = 0; |
216 | if (++s->bp == B_SIZE) |
217 | s->bp = 0; |
218 | if (++s->rp == B_SIZE) |
219 | s->rp = 0; |
220 | } |
221 | |
222 | |
223 | /*********************************************************************** |
224 | // remove node from lists |
225 | ************************************************************************/ |
226 | static void swd_remove_node(lzo_swd_p s, unsigned node) |
227 | { |
228 | if (s->node_count == 0) { |
229 | unsigned key; |
230 | |
231 | key = HEAD3(s->b,node); |
232 | assert(s->llen3[key] > 0); |
233 | --s->llen3[key]; |
234 | |
235 | #ifdef HEAD2 |
236 | key = HEAD2(s->b,node); |
237 | assert(s->head2[key] != NIL2); |
238 | if ((unsigned) s->head2[key] == node) |
239 | s->head2[key] = NIL2; |
240 | #endif |
241 | } else |
242 | --s->node_count; |
243 | } |
244 | |
245 | |
246 | /*********************************************************************** |
247 | // |
248 | ************************************************************************/ |
249 | static void swd_accept(lzo_swd_p s, unsigned n) |
250 | { |
251 | assert(n <= s->look); |
252 | |
253 | while (n--) { |
254 | unsigned key; |
255 | |
256 | swd_remove_node(s,s->rp); |
257 | |
258 | /* add bp into HEAD3 */ |
259 | key = HEAD3(s->b, s->bp); |
260 | s->succ3[s->bp] = s_get_head3(s, key); |
261 | s->head3[key] = s->bp; |
262 | s->best3[s->bp] = SWD_F + 1; |
263 | s->llen3[key]++; |
264 | assert(s->llen3[key] <= SWD_N); |
265 | |
266 | #ifdef HEAD2 |
267 | /* add bp into HEAD2 */ |
268 | key = HEAD2(s->b, s->bp); |
269 | s->head2[key] = s->bp; |
270 | #endif |
271 | |
272 | swd_getbyte(s); |
273 | } |
274 | } |
275 | |
276 | |
277 | /*********************************************************************** |
278 | // |
279 | ************************************************************************/ |
280 | static void swd_search(lzo_swd_p s, unsigned node, unsigned cnt) |
281 | { |
282 | const uint8_t *p1; |
283 | const uint8_t *p2; |
284 | const uint8_t *px; |
285 | unsigned m_len = s->m_len; |
286 | const uint8_t *b = s->b; |
287 | const uint8_t *bp = s->b + s->bp; |
288 | const uint8_t *bx = s->b + s->bp + s->look; |
289 | unsigned char scan_end1; |
290 | |
291 | assert(s->m_len > 0); |
292 | |
293 | scan_end1 = bp[m_len - 1]; |
294 | for ( ; cnt-- > 0; node = s->succ3[node]) { |
295 | p1 = bp; |
296 | p2 = b + node; |
297 | px = bx; |
298 | |
299 | assert(m_len < s->look); |
300 | |
301 | if (p2[m_len - 1] == scan_end1 |
302 | && p2[m_len] == p1[m_len] |
303 | && p2[0] == p1[0] |
304 | && p2[1] == p1[1] |
305 | ) { |
306 | unsigned i; |
307 | assert(lzo_memcmp(bp, &b[node], 3) == 0); |
308 | |
309 | p1 += 2; p2 += 2; |
310 | do {} while (++p1 < px && *p1 == *++p2); |
311 | i = p1-bp; |
312 | |
313 | assert(lzo_memcmp(bp, &b[node], i) == 0); |
314 | |
315 | #if defined(SWD_BEST_OFF) |
316 | if (i < SWD_BEST_OFF) { |
317 | if (s->best_pos[i] == 0) |
318 | s->best_pos[i] = node + 1; |
319 | } |
320 | #endif |
321 | if (i > m_len) { |
322 | s->m_len = m_len = i; |
323 | s->m_pos = node; |
324 | if (m_len == s->look) |
325 | return; |
326 | if (m_len >= SWD_F) |
327 | return; |
328 | if (m_len > (unsigned) s->best3[node]) |
329 | return; |
330 | scan_end1 = bp[m_len - 1]; |
331 | } |
332 | } |
333 | } |
334 | } |
335 | |
336 | |
337 | /*********************************************************************** |
338 | // |
339 | ************************************************************************/ |
340 | #ifdef HEAD2 |
341 | |
342 | static int swd_search2(lzo_swd_p s) |
343 | { |
344 | unsigned key; |
345 | |
346 | assert(s->look >= 2); |
347 | assert(s->m_len > 0); |
348 | |
349 | key = s->head2[HEAD2(s->b, s->bp)]; |
350 | if (key == NIL2) |
351 | return 0; |
352 | assert(lzo_memcmp(&s->b[s->bp], &s->b[key], 2) == 0); |
353 | #if defined(SWD_BEST_OFF) |
354 | if (s->best_pos[2] == 0) |
355 | s->best_pos[2] = key + 1; |
356 | #endif |
357 | |
358 | if (s->m_len < 2) { |
359 | s->m_len = 2; |
360 | s->m_pos = key; |
361 | } |
362 | return 1; |
363 | } |
364 | |
365 | #endif |
366 | |
367 | |
368 | /*********************************************************************** |
369 | // |
370 | ************************************************************************/ |
371 | static void swd_findbest(lzo_swd_p s) |
372 | { |
373 | unsigned key; |
374 | unsigned cnt, node; |
375 | unsigned len; |
376 | |
377 | assert(s->m_len > 0); |
378 | |
379 | /* get current head, add bp into HEAD3 */ |
380 | key = HEAD3(s->b,s->bp); |
381 | node = s->succ3[s->bp] = s_get_head3(s, key); |
382 | cnt = s->llen3[key]++; |
383 | assert(s->llen3[key] <= SWD_N + SWD_F); |
384 | if (cnt > s->max_chain) |
385 | cnt = s->max_chain; |
386 | s->head3[key] = s->bp; |
387 | |
388 | s->b_char = s->b[s->bp]; |
389 | len = s->m_len; |
390 | if (s->m_len >= s->look) { |
391 | if (s->look == 0) |
392 | s->b_char = -1; |
393 | s->m_off = 0; |
394 | s->best3[s->bp] = SWD_F + 1; |
395 | } else { |
396 | #ifdef HEAD2 |
397 | if (swd_search2(s)) |
398 | #endif |
399 | if (s->look >= 3) |
400 | swd_search(s, node, cnt); |
401 | if (s->m_len > len) |
402 | s->m_off = swd_pos2off(s,s->m_pos); |
403 | s->best3[s->bp] = s->m_len; |
404 | |
405 | #if defined(SWD_BEST_OFF) |
406 | if (s->use_best_off) { |
407 | int i; |
408 | for (i = 2; i < SWD_BEST_OFF; i++) { |
409 | if (s->best_pos[i] > 0) |
410 | s->best_off[i] = swd_pos2off(s, s->best_pos[i]-1); |
411 | else |
412 | s->best_off[i] = 0; |
413 | } |
414 | } |
415 | #endif |
416 | } |
417 | |
418 | swd_remove_node(s,s->rp); |
419 | |
420 | #ifdef HEAD2 |
421 | /* add bp into HEAD2 */ |
422 | key = HEAD2(s->b, s->bp); |
423 | s->head2[key] = s->bp; |
424 | #endif |
425 | } |
426 | |
427 | #undef HEAD3 |
428 | #undef HEAD2 |
429 | #undef s_get_head3 |
430 | |
431 | |
432 | /*********************************************************************** |
433 | // |
434 | ************************************************************************/ |
435 | static int init_match(lzo1x_999_t *c, lzo_swd_p s, uint32_t use_best_off) |
436 | { |
437 | int r; |
438 | |
439 | assert(!c->init); |
440 | c->init = 1; |
441 | |
442 | s->c = c; |
443 | |
444 | r = swd_init(s); |
445 | if (r != 0) |
446 | return r; |
447 | |
448 | s->use_best_off = use_best_off; |
449 | return r; |
450 | } |
451 | |
452 | |
453 | /*********************************************************************** |
454 | // |
455 | ************************************************************************/ |
456 | static int find_match(lzo1x_999_t *c, lzo_swd_p s, |
457 | unsigned this_len, unsigned skip) |
458 | { |
459 | assert(c->init); |
460 | |
461 | if (skip > 0) { |
462 | assert(this_len >= skip); |
463 | swd_accept(s, this_len - skip); |
464 | } else { |
465 | assert(this_len <= 1); |
466 | } |
467 | |
468 | s->m_len = 1; |
469 | s->m_len = 1; |
470 | #ifdef SWD_BEST_OFF |
471 | if (s->use_best_off) |
472 | memset(s->best_pos, 0, sizeof(s->best_pos)); |
473 | #endif |
474 | swd_findbest(s); |
475 | c->m_len = s->m_len; |
476 | c->m_off = s->m_off; |
477 | |
478 | swd_getbyte(s); |
479 | |
480 | if (s->b_char < 0) { |
481 | c->look = 0; |
482 | c->m_len = 0; |
483 | } else { |
484 | c->look = s->look + 1; |
485 | } |
486 | c->bp = c->ip - c->look; |
487 | |
488 | return LZO_E_OK; |
489 | } |
490 | |
491 | /* this is a public functions, but there is no prototype in a header file */ |
492 | static int lzo1x_999_compress_internal(const uint8_t *in , unsigned in_len, |
493 | uint8_t *out, unsigned *out_len, |
494 | void *wrkmem, |
495 | unsigned good_length, |
496 | unsigned max_lazy, |
497 | unsigned max_chain, |
498 | uint32_t use_best_off); |
499 | |
500 | |
501 | /*********************************************************************** |
502 | // |
503 | ************************************************************************/ |
504 | static uint8_t *code_match(lzo1x_999_t *c, |
505 | uint8_t *op, unsigned m_len, unsigned m_off) |
506 | { |
507 | assert(op > c->out); |
508 | if (m_len == 2) { |
509 | assert(m_off <= M1_MAX_OFFSET); |
510 | assert(c->r1_lit > 0); |
511 | assert(c->r1_lit < 4); |
512 | m_off -= 1; |
513 | *op++ = M1_MARKER | ((m_off & 3) << 2); |
514 | *op++ = m_off >> 2; |
515 | } else if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) { |
516 | assert(m_len >= 3); |
517 | m_off -= 1; |
518 | *op++ = ((m_len - 1) << 5) | ((m_off & 7) << 2); |
519 | *op++ = m_off >> 3; |
520 | assert(op[-2] >= M2_MARKER); |
521 | } else if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && c->r1_lit >= 4) { |
522 | assert(m_len == 3); |
523 | assert(m_off > M2_MAX_OFFSET); |
524 | m_off -= 1 + M2_MAX_OFFSET; |
525 | *op++ = M1_MARKER | ((m_off & 3) << 2); |
526 | *op++ = m_off >> 2; |
527 | } else if (m_off <= M3_MAX_OFFSET) { |
528 | assert(m_len >= 3); |
529 | m_off -= 1; |
530 | if (m_len <= M3_MAX_LEN) |
531 | *op++ = M3_MARKER | (m_len - 2); |
532 | else { |
533 | m_len -= M3_MAX_LEN; |
534 | *op++ = M3_MARKER | 0; |
535 | while (m_len > 255) { |
536 | m_len -= 255; |
537 | *op++ = 0; |
538 | } |
539 | assert(m_len > 0); |
540 | *op++ = m_len; |
541 | } |
542 | *op++ = m_off << 2; |
543 | *op++ = m_off >> 6; |
544 | } else { |
545 | unsigned k; |
546 | |
547 | assert(m_len >= 3); |
548 | assert(m_off > 0x4000); |
549 | assert(m_off <= 0xbfff); |
550 | m_off -= 0x4000; |
551 | k = (m_off & 0x4000) >> 11; |
552 | if (m_len <= M4_MAX_LEN) |
553 | *op++ = M4_MARKER | k | (m_len - 2); |
554 | else { |
555 | m_len -= M4_MAX_LEN; |
556 | *op++ = M4_MARKER | k | 0; |
557 | while (m_len > 255) { |
558 | m_len -= 255; |
559 | *op++ = 0; |
560 | } |
561 | assert(m_len > 0); |
562 | *op++ = m_len; |
563 | } |
564 | *op++ = m_off << 2; |
565 | *op++ = m_off >> 6; |
566 | } |
567 | |
568 | return op; |
569 | } |
570 | |
571 | |
572 | static uint8_t *STORE_RUN(lzo1x_999_t *c, uint8_t *op, |
573 | const uint8_t *ii, unsigned t) |
574 | { |
575 | if (op == c->out && t <= 238) { |
576 | *op++ = 17 + t; |
577 | } else if (t <= 3) { |
578 | op[-2] |= t; |
579 | } else if (t <= 18) { |
580 | *op++ = t - 3; |
581 | } else { |
582 | unsigned tt = t - 18; |
583 | |
584 | *op++ = 0; |
585 | while (tt > 255) { |
586 | tt -= 255; |
587 | *op++ = 0; |
588 | } |
589 | assert(tt > 0); |
590 | *op++ = tt; |
591 | } |
592 | do *op++ = *ii++; while (--t > 0); |
593 | |
594 | return op; |
595 | } |
596 | |
597 | |
598 | static uint8_t *code_run(lzo1x_999_t *c, uint8_t *op, const uint8_t *ii, |
599 | unsigned lit) |
600 | { |
601 | if (lit > 0) { |
602 | assert(m_len >= 2); |
603 | op = STORE_RUN(c, op, ii, lit); |
604 | } else { |
605 | assert(m_len >= 3); |
606 | } |
607 | c->r1_lit = lit; |
608 | |
609 | return op; |
610 | } |
611 | |
612 | |
613 | /*********************************************************************** |
614 | // |
615 | ************************************************************************/ |
616 | static int len_of_coded_match(unsigned m_len, unsigned m_off, unsigned lit) |
617 | { |
618 | int n = 4; |
619 | |
620 | if (m_len < 2) |
621 | return -1; |
622 | if (m_len == 2) |
623 | return (m_off <= M1_MAX_OFFSET && lit > 0 && lit < 4) ? 2 : -1; |
624 | if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) |
625 | return 2; |
626 | if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && lit >= 4) |
627 | return 2; |
628 | if (m_off <= M3_MAX_OFFSET) { |
629 | if (m_len <= M3_MAX_LEN) |
630 | return 3; |
631 | m_len -= M3_MAX_LEN; |
632 | } else if (m_off <= M4_MAX_OFFSET) { |
633 | if (m_len <= M4_MAX_LEN) |
634 | return 3; |
635 | m_len -= M4_MAX_LEN; |
636 | } else |
637 | return -1; |
638 | while (m_len > 255) { |
639 | m_len -= 255; |
640 | n++; |
641 | } |
642 | return n; |
643 | } |
644 | |
645 | |
646 | static int min_gain(unsigned ahead, unsigned lit1, |
647 | unsigned lit2, int l1, int l2, int l3) |
648 | { |
649 | int lazy_match_min_gain = 0; |
650 | |
651 | assert (ahead >= 1); |
652 | lazy_match_min_gain += ahead; |
653 | |
654 | if (lit1 <= 3) |
655 | lazy_match_min_gain += (lit2 <= 3) ? 0 : 2; |
656 | else if (lit1 <= 18) |
657 | lazy_match_min_gain += (lit2 <= 18) ? 0 : 1; |
658 | |
659 | lazy_match_min_gain += (l2 - l1) * 2; |
660 | if (l3 > 0) |
661 | lazy_match_min_gain -= (ahead - l3) * 2; |
662 | |
663 | if (lazy_match_min_gain < 0) |
664 | lazy_match_min_gain = 0; |
665 | |
666 | return lazy_match_min_gain; |
667 | } |
668 | |
669 | |
670 | /*********************************************************************** |
671 | // |
672 | ************************************************************************/ |
673 | #if defined(SWD_BEST_OFF) |
674 | |
675 | static void better_match(const lzo_swd_p swd, |
676 | unsigned *m_len, unsigned *m_off) |
677 | { |
678 | |
679 | if (*m_len <= M2_MIN_LEN) |
680 | return; |
681 | |
682 | if (*m_off <= M2_MAX_OFFSET) |
683 | return; |
684 | |
685 | /* M3/M4 -> M2 */ |
686 | if (*m_off > M2_MAX_OFFSET |
687 | && *m_len >= M2_MIN_LEN + 1 && *m_len <= M2_MAX_LEN + 1 |
688 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M2_MAX_OFFSET |
689 | ) { |
690 | *m_len = *m_len - 1; |
691 | *m_off = swd->best_off[*m_len]; |
692 | return; |
693 | } |
694 | |
695 | /* M4 -> M2 */ |
696 | if (*m_off > M3_MAX_OFFSET |
697 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M2_MAX_LEN + 2 |
698 | && swd->best_off[*m_len-2] && swd->best_off[*m_len-2] <= M2_MAX_OFFSET |
699 | ) { |
700 | *m_len = *m_len - 2; |
701 | *m_off = swd->best_off[*m_len]; |
702 | return; |
703 | } |
704 | /* M4 -> M3 */ |
705 | if (*m_off > M3_MAX_OFFSET |
706 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M3_MAX_LEN + 1 |
707 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M3_MAX_OFFSET |
708 | ) { |
709 | *m_len = *m_len - 1; |
710 | *m_off = swd->best_off[*m_len]; |
711 | } |
712 | } |
713 | |
714 | #endif |
715 | |
716 | |
717 | /*********************************************************************** |
718 | // |
719 | ************************************************************************/ |
720 | static int lzo1x_999_compress_internal(const uint8_t *in, unsigned in_len, |
721 | uint8_t *out, unsigned *out_len, |
722 | void *wrkmem, |
723 | unsigned good_length, |
724 | unsigned max_lazy, |
725 | unsigned max_chain, |
726 | uint32_t use_best_off) |
727 | { |
728 | uint8_t *op; |
729 | const uint8_t *ii; |
730 | unsigned lit; |
731 | unsigned m_len, m_off; |
732 | lzo1x_999_t cc; |
733 | lzo1x_999_t *const c = &cc; |
734 | const lzo_swd_p swd = (lzo_swd_p) wrkmem; |
735 | int r; |
736 | |
737 | c->init = 0; |
738 | c->ip = c->in = in; |
739 | c->in_end = in + in_len; |
740 | c->out = out; |
741 | |
742 | op = out; |
743 | ii = c->ip; /* point to start of literal run */ |
744 | lit = 0; |
745 | c->r1_lit = 0; |
746 | |
747 | r = init_match(c, swd, use_best_off); |
748 | if (r != 0) |
749 | return r; |
750 | swd->max_chain = max_chain; |
751 | |
752 | r = find_match(c, swd, 0, 0); |
753 | if (r != 0) |
754 | return r; |
755 | |
756 | while (c->look > 0) { |
757 | unsigned ahead; |
758 | unsigned max_ahead; |
759 | int l1, l2, l3; |
760 | |
761 | m_len = c->m_len; |
762 | m_off = c->m_off; |
763 | |
764 | assert(c->bp == c->ip - c->look); |
765 | assert(c->bp >= in); |
766 | if (lit == 0) |
767 | ii = c->bp; |
768 | assert(ii + lit == c->bp); |
769 | assert(swd->b_char == *(c->bp)); |
770 | |
771 | if (m_len < 2 |
772 | || (m_len == 2 && (m_off > M1_MAX_OFFSET || lit == 0 || lit >= 4)) |
773 | /* Do not accept this match for compressed-data compatibility |
774 | * with LZO v1.01 and before |
775 | * [ might be a problem for decompress() and optimize() ] |
776 | */ |
777 | || (m_len == 2 && op == out) |
778 | || (op == out && lit == 0) |
779 | ) { |
780 | /* a literal */ |
781 | m_len = 0; |
782 | } |
783 | else if (m_len == M2_MIN_LEN) { |
784 | /* compression ratio improves if we code a literal in some cases */ |
785 | if (m_off > MX_MAX_OFFSET && lit >= 4) |
786 | m_len = 0; |
787 | } |
788 | |
789 | if (m_len == 0) { |
790 | /* a literal */ |
791 | lit++; |
792 | swd->max_chain = max_chain; |
793 | r = find_match(c, swd, 1, 0); |
794 | assert(r == 0); |
795 | continue; |
796 | } |
797 | |
798 | /* a match */ |
799 | #if defined(SWD_BEST_OFF) |
800 | if (swd->use_best_off) |
801 | better_match(swd, &m_len, &m_off); |
802 | #endif |
803 | |
804 | /* shall we try a lazy match ? */ |
805 | ahead = 0; |
806 | if (m_len >= max_lazy) { |
807 | /* no */ |
808 | l1 = 0; |
809 | max_ahead = 0; |
810 | } else { |
811 | /* yes, try a lazy match */ |
812 | l1 = len_of_coded_match(m_len, m_off, lit); |
813 | assert(l1 > 0); |
814 | max_ahead = LZO_MIN(2, (unsigned)l1 - 1); |
815 | } |
816 | |
817 | |
818 | while (ahead < max_ahead && c->look > m_len) { |
819 | int lazy_match_min_gain; |
820 | |
821 | if (m_len >= good_length) |
822 | swd->max_chain = max_chain >> 2; |
823 | else |
824 | swd->max_chain = max_chain; |
825 | r = find_match(c, swd, 1, 0); |
826 | ahead++; |
827 | |
828 | assert(r == 0); |
829 | assert(c->look > 0); |
830 | assert(ii + lit + ahead == c->bp); |
831 | |
832 | if (c->m_len < m_len) |
833 | continue; |
834 | if (c->m_len == m_len && c->m_off >= m_off) |
835 | continue; |
836 | #if defined(SWD_BEST_OFF) |
837 | if (swd->use_best_off) |
838 | better_match(swd, &c->m_len, &c->m_off); |
839 | #endif |
840 | l2 = len_of_coded_match(c->m_len, c->m_off, lit+ahead); |
841 | if (l2 < 0) |
842 | continue; |
843 | |
844 | /* compressed-data compatibility [see above] */ |
845 | l3 = (op == out) ? -1 : len_of_coded_match(ahead, m_off, lit); |
846 | |
847 | lazy_match_min_gain = min_gain(ahead, lit, lit+ahead, l1, l2, l3); |
848 | if (c->m_len >= m_len + lazy_match_min_gain) { |
849 | if (l3 > 0) { |
850 | /* code previous run */ |
851 | op = code_run(c, op, ii, lit); |
852 | lit = 0; |
853 | /* code shortened match */ |
854 | op = code_match(c, op, ahead, m_off); |
855 | } else { |
856 | lit += ahead; |
857 | assert(ii + lit == c->bp); |
858 | } |
859 | goto lazy_match_done; |
860 | } |
861 | } |
862 | |
863 | assert(ii + lit + ahead == c->bp); |
864 | |
865 | /* 1 - code run */ |
866 | op = code_run(c, op, ii, lit); |
867 | lit = 0; |
868 | |
869 | /* 2 - code match */ |
870 | op = code_match(c, op, m_len, m_off); |
871 | swd->max_chain = max_chain; |
872 | r = find_match(c, swd, m_len, 1+ahead); |
873 | assert(r == 0); |
874 | |
875 | lazy_match_done: ; |
876 | } |
877 | |
878 | /* store final run */ |
879 | if (lit > 0) |
880 | op = STORE_RUN(c, op, ii, lit); |
881 | |
882 | #if defined(LZO_EOF_CODE) |
883 | *op++ = M4_MARKER | 1; |
884 | *op++ = 0; |
885 | *op++ = 0; |
886 | #endif |
887 | |
888 | *out_len = op - out; |
889 | |
890 | return LZO_E_OK; |
891 | } |
892 | |
893 | |
894 | /*********************************************************************** |
895 | // |
896 | ************************************************************************/ |
897 | int lzo1x_999_compress_level(const uint8_t *in, unsigned in_len, |
898 | uint8_t *out, unsigned *out_len, |
899 | void *wrkmem, |
900 | int compression_level) |
901 | { |
902 | static const struct { |
903 | uint16_t good_length; |
904 | uint16_t max_lazy; |
905 | uint16_t max_chain; |
906 | uint16_t use_best_off; |
907 | } c[3] = { |
908 | { 8, 32, 256, 0 }, |
909 | { 32, 128, 2048, 1 }, |
910 | { SWD_F, SWD_F, 4096, 1 } /* max. compression */ |
911 | }; |
912 | |
913 | if (compression_level < 7 || compression_level > 9) |
914 | return LZO_E_ERROR; |
915 | |
916 | compression_level -= 7; |
917 | return lzo1x_999_compress_internal(in, in_len, out, out_len, wrkmem, |
918 | c[compression_level].good_length, |
919 | c[compression_level].max_lazy, |
920 | c[compression_level].max_chain, |
921 | c[compression_level].use_best_off); |
922 | } |