blob: 09ee4ba5c3b16885bdd3f89e473192d2ff956afd
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 | } lzo1x_999_t; |
75 | |
76 | #define getbyte(c) ((c).ip < (c).in_end ? *((c).ip)++ : (-1)) |
77 | |
78 | /* lzo_swd.c -- sliding window dictionary */ |
79 | |
80 | /*********************************************************************** |
81 | // |
82 | ************************************************************************/ |
83 | #define SWD_UINT_MAX USHRT_MAX |
84 | |
85 | #ifndef SWD_HSIZE |
86 | # define SWD_HSIZE 16384 |
87 | #endif |
88 | #ifndef SWD_MAX_CHAIN |
89 | # define SWD_MAX_CHAIN 2048 |
90 | #endif |
91 | |
92 | #define HEAD3(b, p) \ |
93 | ( ((0x9f5f * ((((b[p]<<5)^b[p+1])<<5) ^ b[p+2])) >> 5) & (SWD_HSIZE-1) ) |
94 | |
95 | #if defined(LZO_UNALIGNED_OK_2) |
96 | # define HEAD2(b,p) (* (bb__aliased_uint16_t *) &(b[p])) |
97 | #else |
98 | # define HEAD2(b,p) (b[p] ^ ((unsigned)b[p+1]<<8)) |
99 | #endif |
100 | #define NIL2 SWD_UINT_MAX |
101 | |
102 | typedef struct lzo_swd { |
103 | /* public - "built-in" */ |
104 | |
105 | /* public - configuration */ |
106 | unsigned max_chain; |
107 | int use_best_off; |
108 | |
109 | /* public - output */ |
110 | unsigned m_len; |
111 | unsigned m_off; |
112 | unsigned look; |
113 | int b_char; |
114 | #if defined(SWD_BEST_OFF) |
115 | unsigned best_off[SWD_BEST_OFF]; |
116 | #endif |
117 | |
118 | /* semi public */ |
119 | lzo1x_999_t *c; |
120 | unsigned m_pos; |
121 | #if defined(SWD_BEST_OFF) |
122 | unsigned best_pos[SWD_BEST_OFF]; |
123 | #endif |
124 | |
125 | /* private */ |
126 | unsigned ip; /* input pointer (lookahead) */ |
127 | unsigned bp; /* buffer pointer */ |
128 | unsigned rp; /* remove pointer */ |
129 | |
130 | unsigned node_count; |
131 | unsigned first_rp; |
132 | |
133 | uint8_t b[SWD_N + SWD_F]; |
134 | uint8_t b_wrap[SWD_F]; /* must follow b */ |
135 | uint16_t head3[SWD_HSIZE]; |
136 | uint16_t succ3[SWD_N + SWD_F]; |
137 | uint16_t best3[SWD_N + SWD_F]; |
138 | uint16_t llen3[SWD_HSIZE]; |
139 | #ifdef HEAD2 |
140 | uint16_t head2[65536L]; |
141 | #endif |
142 | } lzo_swd_t, *lzo_swd_p; |
143 | |
144 | #define SIZEOF_LZO_SWD_T (sizeof(lzo_swd_t)) |
145 | |
146 | |
147 | /* Access macro for head3. |
148 | * head3[key] may be uninitialized, but then its value will never be used. |
149 | */ |
150 | #define s_get_head3(s,key) s->head3[key] |
151 | |
152 | |
153 | /*********************************************************************** |
154 | // |
155 | ************************************************************************/ |
156 | #define B_SIZE (SWD_N + SWD_F) |
157 | |
158 | static int swd_init(lzo_swd_p s) |
159 | { |
160 | /* defaults */ |
161 | s->node_count = SWD_N; |
162 | |
163 | memset(s->llen3, 0, sizeof(s->llen3[0]) * (unsigned)SWD_HSIZE); |
164 | #ifdef HEAD2 |
165 | memset(s->head2, 0xff, sizeof(s->head2[0]) * 65536L); |
166 | assert(s->head2[0] == NIL2); |
167 | #endif |
168 | |
169 | s->ip = 0; |
170 | s->bp = s->ip; |
171 | s->first_rp = s->ip; |
172 | |
173 | assert(s->ip + SWD_F <= B_SIZE); |
174 | s->look = (unsigned) (s->c->in_end - s->c->ip); |
175 | if (s->look > 0) { |
176 | if (s->look > SWD_F) |
177 | s->look = SWD_F; |
178 | memcpy(&s->b[s->ip], s->c->ip, s->look); |
179 | s->c->ip += s->look; |
180 | s->ip += s->look; |
181 | } |
182 | if (s->ip == B_SIZE) |
183 | s->ip = 0; |
184 | |
185 | s->rp = s->first_rp; |
186 | if (s->rp >= s->node_count) |
187 | s->rp -= s->node_count; |
188 | else |
189 | s->rp += B_SIZE - s->node_count; |
190 | |
191 | return LZO_E_OK; |
192 | } |
193 | |
194 | #define swd_pos2off(s,pos) \ |
195 | (s->bp > (pos) ? s->bp - (pos) : B_SIZE - ((pos) - s->bp)) |
196 | |
197 | |
198 | /*********************************************************************** |
199 | // |
200 | ************************************************************************/ |
201 | static void swd_getbyte(lzo_swd_p s) |
202 | { |
203 | int c; |
204 | |
205 | if ((c = getbyte(*(s->c))) < 0) { |
206 | if (s->look > 0) |
207 | --s->look; |
208 | } else { |
209 | s->b[s->ip] = c; |
210 | if (s->ip < SWD_F) |
211 | s->b_wrap[s->ip] = c; |
212 | } |
213 | if (++s->ip == B_SIZE) |
214 | s->ip = 0; |
215 | if (++s->bp == B_SIZE) |
216 | s->bp = 0; |
217 | if (++s->rp == B_SIZE) |
218 | s->rp = 0; |
219 | } |
220 | |
221 | |
222 | /*********************************************************************** |
223 | // remove node from lists |
224 | ************************************************************************/ |
225 | static void swd_remove_node(lzo_swd_p s, unsigned node) |
226 | { |
227 | if (s->node_count == 0) { |
228 | unsigned key; |
229 | |
230 | key = HEAD3(s->b,node); |
231 | assert(s->llen3[key] > 0); |
232 | --s->llen3[key]; |
233 | |
234 | #ifdef HEAD2 |
235 | key = HEAD2(s->b,node); |
236 | assert(s->head2[key] != NIL2); |
237 | if ((unsigned) s->head2[key] == node) |
238 | s->head2[key] = NIL2; |
239 | #endif |
240 | } else |
241 | --s->node_count; |
242 | } |
243 | |
244 | |
245 | /*********************************************************************** |
246 | // |
247 | ************************************************************************/ |
248 | static void swd_accept(lzo_swd_p s, unsigned n) |
249 | { |
250 | assert(n <= s->look); |
251 | |
252 | while (n--) { |
253 | unsigned key; |
254 | |
255 | swd_remove_node(s,s->rp); |
256 | |
257 | /* add bp into HEAD3 */ |
258 | key = HEAD3(s->b, s->bp); |
259 | s->succ3[s->bp] = s_get_head3(s, key); |
260 | s->head3[key] = s->bp; |
261 | s->best3[s->bp] = SWD_F + 1; |
262 | s->llen3[key]++; |
263 | assert(s->llen3[key] <= SWD_N); |
264 | |
265 | #ifdef HEAD2 |
266 | /* add bp into HEAD2 */ |
267 | key = HEAD2(s->b, s->bp); |
268 | s->head2[key] = s->bp; |
269 | #endif |
270 | |
271 | swd_getbyte(s); |
272 | } |
273 | } |
274 | |
275 | |
276 | /*********************************************************************** |
277 | // |
278 | ************************************************************************/ |
279 | static void swd_search(lzo_swd_p s, unsigned node, unsigned cnt) |
280 | { |
281 | const uint8_t *p1; |
282 | const uint8_t *p2; |
283 | const uint8_t *px; |
284 | unsigned m_len = s->m_len; |
285 | const uint8_t *b = s->b; |
286 | const uint8_t *bp = s->b + s->bp; |
287 | const uint8_t *bx = s->b + s->bp + s->look; |
288 | unsigned char scan_end1; |
289 | |
290 | assert(s->m_len > 0); |
291 | |
292 | scan_end1 = bp[m_len - 1]; |
293 | for ( ; cnt-- > 0; node = s->succ3[node]) { |
294 | p1 = bp; |
295 | p2 = b + node; |
296 | px = bx; |
297 | |
298 | assert(m_len < s->look); |
299 | |
300 | if (p2[m_len - 1] == scan_end1 |
301 | && p2[m_len] == p1[m_len] |
302 | && p2[0] == p1[0] |
303 | && p2[1] == p1[1] |
304 | ) { |
305 | unsigned i; |
306 | assert(lzo_memcmp(bp, &b[node], 3) == 0); |
307 | |
308 | p1 += 2; p2 += 2; |
309 | do {} while (++p1 < px && *p1 == *++p2); |
310 | i = p1-bp; |
311 | |
312 | assert(lzo_memcmp(bp, &b[node], i) == 0); |
313 | |
314 | #if defined(SWD_BEST_OFF) |
315 | if (i < SWD_BEST_OFF) { |
316 | if (s->best_pos[i] == 0) |
317 | s->best_pos[i] = node + 1; |
318 | } |
319 | #endif |
320 | if (i > m_len) { |
321 | s->m_len = m_len = i; |
322 | s->m_pos = node; |
323 | if (m_len == s->look) |
324 | return; |
325 | if (m_len >= SWD_F) |
326 | return; |
327 | if (m_len > (unsigned) s->best3[node]) |
328 | return; |
329 | scan_end1 = bp[m_len - 1]; |
330 | } |
331 | } |
332 | } |
333 | } |
334 | |
335 | |
336 | /*********************************************************************** |
337 | // |
338 | ************************************************************************/ |
339 | #ifdef HEAD2 |
340 | |
341 | static int swd_search2(lzo_swd_p s) |
342 | { |
343 | unsigned key; |
344 | |
345 | assert(s->look >= 2); |
346 | assert(s->m_len > 0); |
347 | |
348 | key = s->head2[HEAD2(s->b, s->bp)]; |
349 | if (key == NIL2) |
350 | return 0; |
351 | assert(lzo_memcmp(&s->b[s->bp], &s->b[key], 2) == 0); |
352 | #if defined(SWD_BEST_OFF) |
353 | if (s->best_pos[2] == 0) |
354 | s->best_pos[2] = key + 1; |
355 | #endif |
356 | |
357 | if (s->m_len < 2) { |
358 | s->m_len = 2; |
359 | s->m_pos = key; |
360 | } |
361 | return 1; |
362 | } |
363 | |
364 | #endif |
365 | |
366 | |
367 | /*********************************************************************** |
368 | // |
369 | ************************************************************************/ |
370 | static void swd_findbest(lzo_swd_p s) |
371 | { |
372 | unsigned key; |
373 | unsigned cnt, node; |
374 | unsigned len; |
375 | |
376 | assert(s->m_len > 0); |
377 | |
378 | /* get current head, add bp into HEAD3 */ |
379 | key = HEAD3(s->b,s->bp); |
380 | node = s->succ3[s->bp] = s_get_head3(s, key); |
381 | cnt = s->llen3[key]++; |
382 | assert(s->llen3[key] <= SWD_N + SWD_F); |
383 | if (cnt > s->max_chain) |
384 | cnt = s->max_chain; |
385 | s->head3[key] = s->bp; |
386 | |
387 | s->b_char = s->b[s->bp]; |
388 | len = s->m_len; |
389 | if (s->m_len >= s->look) { |
390 | if (s->look == 0) |
391 | s->b_char = -1; |
392 | s->m_off = 0; |
393 | s->best3[s->bp] = SWD_F + 1; |
394 | } else { |
395 | #ifdef HEAD2 |
396 | if (swd_search2(s)) |
397 | #endif |
398 | if (s->look >= 3) |
399 | swd_search(s, node, cnt); |
400 | if (s->m_len > len) |
401 | s->m_off = swd_pos2off(s,s->m_pos); |
402 | s->best3[s->bp] = s->m_len; |
403 | |
404 | #if defined(SWD_BEST_OFF) |
405 | if (s->use_best_off) { |
406 | int i; |
407 | for (i = 2; i < SWD_BEST_OFF; i++) { |
408 | if (s->best_pos[i] > 0) |
409 | s->best_off[i] = swd_pos2off(s, s->best_pos[i]-1); |
410 | else |
411 | s->best_off[i] = 0; |
412 | } |
413 | } |
414 | #endif |
415 | } |
416 | |
417 | swd_remove_node(s,s->rp); |
418 | |
419 | #ifdef HEAD2 |
420 | /* add bp into HEAD2 */ |
421 | key = HEAD2(s->b, s->bp); |
422 | s->head2[key] = s->bp; |
423 | #endif |
424 | } |
425 | |
426 | #undef HEAD3 |
427 | #undef HEAD2 |
428 | #undef s_get_head3 |
429 | |
430 | |
431 | /*********************************************************************** |
432 | // |
433 | ************************************************************************/ |
434 | static int init_match(lzo1x_999_t *c, lzo_swd_p s, uint32_t use_best_off) |
435 | { |
436 | int r; |
437 | |
438 | assert(!c->init); |
439 | c->init = 1; |
440 | |
441 | s->c = c; |
442 | |
443 | r = swd_init(s); |
444 | if (r != 0) |
445 | return r; |
446 | |
447 | s->use_best_off = use_best_off; |
448 | return r; |
449 | } |
450 | |
451 | |
452 | /*********************************************************************** |
453 | // |
454 | ************************************************************************/ |
455 | static int find_match(lzo1x_999_t *c, lzo_swd_p s, |
456 | unsigned this_len, unsigned skip) |
457 | { |
458 | assert(c->init); |
459 | |
460 | if (skip > 0) { |
461 | assert(this_len >= skip); |
462 | swd_accept(s, this_len - skip); |
463 | } else { |
464 | assert(this_len <= 1); |
465 | } |
466 | |
467 | s->m_len = 1; |
468 | #ifdef SWD_BEST_OFF |
469 | if (s->use_best_off) |
470 | memset(s->best_pos, 0, sizeof(s->best_pos)); |
471 | #endif |
472 | swd_findbest(s); |
473 | c->m_len = s->m_len; |
474 | c->m_off = s->m_off; |
475 | |
476 | swd_getbyte(s); |
477 | |
478 | if (s->b_char < 0) { |
479 | c->look = 0; |
480 | c->m_len = 0; |
481 | } else { |
482 | c->look = s->look + 1; |
483 | } |
484 | c->bp = c->ip - c->look; |
485 | |
486 | return LZO_E_OK; |
487 | } |
488 | |
489 | /* this is a public functions, but there is no prototype in a header file */ |
490 | static int lzo1x_999_compress_internal(const uint8_t *in , unsigned in_len, |
491 | uint8_t *out, unsigned *out_len, |
492 | void *wrkmem, |
493 | unsigned good_length, |
494 | unsigned max_lazy, |
495 | unsigned max_chain, |
496 | uint32_t use_best_off); |
497 | |
498 | |
499 | /*********************************************************************** |
500 | // |
501 | ************************************************************************/ |
502 | static uint8_t *code_match(lzo1x_999_t *c, |
503 | uint8_t *op, unsigned m_len, unsigned m_off) |
504 | { |
505 | assert(op > c->out); |
506 | if (m_len == 2) { |
507 | assert(m_off <= M1_MAX_OFFSET); |
508 | assert(c->r1_lit > 0); |
509 | assert(c->r1_lit < 4); |
510 | m_off -= 1; |
511 | *op++ = M1_MARKER | ((m_off & 3) << 2); |
512 | *op++ = m_off >> 2; |
513 | } else if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) { |
514 | assert(m_len >= 3); |
515 | m_off -= 1; |
516 | *op++ = ((m_len - 1) << 5) | ((m_off & 7) << 2); |
517 | *op++ = m_off >> 3; |
518 | assert(op[-2] >= M2_MARKER); |
519 | } else if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && c->r1_lit >= 4) { |
520 | assert(m_len == 3); |
521 | assert(m_off > M2_MAX_OFFSET); |
522 | m_off -= 1 + M2_MAX_OFFSET; |
523 | *op++ = M1_MARKER | ((m_off & 3) << 2); |
524 | *op++ = m_off >> 2; |
525 | } else if (m_off <= M3_MAX_OFFSET) { |
526 | assert(m_len >= 3); |
527 | m_off -= 1; |
528 | if (m_len <= M3_MAX_LEN) |
529 | *op++ = M3_MARKER | (m_len - 2); |
530 | else { |
531 | m_len -= M3_MAX_LEN; |
532 | *op++ = M3_MARKER | 0; |
533 | while (m_len > 255) { |
534 | m_len -= 255; |
535 | *op++ = 0; |
536 | } |
537 | assert(m_len > 0); |
538 | *op++ = m_len; |
539 | } |
540 | *op++ = m_off << 2; |
541 | *op++ = m_off >> 6; |
542 | } else { |
543 | unsigned k; |
544 | |
545 | assert(m_len >= 3); |
546 | assert(m_off > 0x4000); |
547 | assert(m_off <= 0xbfff); |
548 | m_off -= 0x4000; |
549 | k = (m_off & 0x4000) >> 11; |
550 | if (m_len <= M4_MAX_LEN) |
551 | *op++ = M4_MARKER | k | (m_len - 2); |
552 | else { |
553 | m_len -= M4_MAX_LEN; |
554 | *op++ = M4_MARKER | k | 0; |
555 | while (m_len > 255) { |
556 | m_len -= 255; |
557 | *op++ = 0; |
558 | } |
559 | assert(m_len > 0); |
560 | *op++ = m_len; |
561 | } |
562 | *op++ = m_off << 2; |
563 | *op++ = m_off >> 6; |
564 | } |
565 | |
566 | return op; |
567 | } |
568 | |
569 | |
570 | static uint8_t *STORE_RUN(lzo1x_999_t *c, uint8_t *op, |
571 | const uint8_t *ii, unsigned t) |
572 | { |
573 | if (op == c->out && t <= 238) { |
574 | *op++ = 17 + t; |
575 | } else if (t <= 3) { |
576 | op[-2] |= t; |
577 | } else if (t <= 18) { |
578 | *op++ = t - 3; |
579 | } else { |
580 | unsigned tt = t - 18; |
581 | |
582 | *op++ = 0; |
583 | while (tt > 255) { |
584 | tt -= 255; |
585 | *op++ = 0; |
586 | } |
587 | assert(tt > 0); |
588 | *op++ = tt; |
589 | } |
590 | do *op++ = *ii++; while (--t > 0); |
591 | |
592 | return op; |
593 | } |
594 | |
595 | |
596 | static uint8_t *code_run(lzo1x_999_t *c, uint8_t *op, const uint8_t *ii, |
597 | unsigned lit) |
598 | { |
599 | if (lit > 0) { |
600 | assert(m_len >= 2); |
601 | op = STORE_RUN(c, op, ii, lit); |
602 | } else { |
603 | assert(m_len >= 3); |
604 | } |
605 | c->r1_lit = lit; |
606 | |
607 | return op; |
608 | } |
609 | |
610 | |
611 | /*********************************************************************** |
612 | // |
613 | ************************************************************************/ |
614 | static int len_of_coded_match(unsigned m_len, unsigned m_off, unsigned lit) |
615 | { |
616 | int n = 4; |
617 | |
618 | if (m_len < 2) |
619 | return -1; |
620 | if (m_len == 2) |
621 | return (m_off <= M1_MAX_OFFSET && lit > 0 && lit < 4) ? 2 : -1; |
622 | if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) |
623 | return 2; |
624 | if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && lit >= 4) |
625 | return 2; |
626 | if (m_off <= M3_MAX_OFFSET) { |
627 | if (m_len <= M3_MAX_LEN) |
628 | return 3; |
629 | m_len -= M3_MAX_LEN; |
630 | } else if (m_off <= M4_MAX_OFFSET) { |
631 | if (m_len <= M4_MAX_LEN) |
632 | return 3; |
633 | m_len -= M4_MAX_LEN; |
634 | } else |
635 | return -1; |
636 | while (m_len > 255) { |
637 | m_len -= 255; |
638 | n++; |
639 | } |
640 | return n; |
641 | } |
642 | |
643 | |
644 | static int min_gain(unsigned ahead, unsigned lit1, |
645 | unsigned lit2, int l1, int l2, int l3) |
646 | { |
647 | int lazy_match_min_gain = 0; |
648 | |
649 | assert (ahead >= 1); |
650 | lazy_match_min_gain += ahead; |
651 | |
652 | if (lit1 <= 3) |
653 | lazy_match_min_gain += (lit2 <= 3) ? 0 : 2; |
654 | else if (lit1 <= 18) |
655 | lazy_match_min_gain += (lit2 <= 18) ? 0 : 1; |
656 | |
657 | lazy_match_min_gain += (l2 - l1) * 2; |
658 | if (l3 > 0) |
659 | lazy_match_min_gain -= (ahead - l3) * 2; |
660 | |
661 | if (lazy_match_min_gain < 0) |
662 | lazy_match_min_gain = 0; |
663 | |
664 | return lazy_match_min_gain; |
665 | } |
666 | |
667 | |
668 | /*********************************************************************** |
669 | // |
670 | ************************************************************************/ |
671 | #if defined(SWD_BEST_OFF) |
672 | |
673 | static void better_match(const lzo_swd_p swd, |
674 | unsigned *m_len, unsigned *m_off) |
675 | { |
676 | if (*m_len <= M2_MIN_LEN) |
677 | return; |
678 | |
679 | if (*m_off <= M2_MAX_OFFSET) |
680 | return; |
681 | |
682 | /* M3/M4 -> M2 */ |
683 | if (*m_off > M2_MAX_OFFSET |
684 | && *m_len >= M2_MIN_LEN + 1 && *m_len <= M2_MAX_LEN + 1 |
685 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M2_MAX_OFFSET |
686 | ) { |
687 | *m_len = *m_len - 1; |
688 | *m_off = swd->best_off[*m_len]; |
689 | return; |
690 | } |
691 | |
692 | /* M4 -> M2 */ |
693 | if (*m_off > M3_MAX_OFFSET |
694 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M2_MAX_LEN + 2 |
695 | && swd->best_off[*m_len-2] && swd->best_off[*m_len-2] <= M2_MAX_OFFSET |
696 | ) { |
697 | *m_len = *m_len - 2; |
698 | *m_off = swd->best_off[*m_len]; |
699 | return; |
700 | } |
701 | /* M4 -> M3 */ |
702 | if (*m_off > M3_MAX_OFFSET |
703 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M3_MAX_LEN + 1 |
704 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M3_MAX_OFFSET |
705 | ) { |
706 | *m_len = *m_len - 1; |
707 | *m_off = swd->best_off[*m_len]; |
708 | } |
709 | } |
710 | |
711 | #endif |
712 | |
713 | |
714 | /*********************************************************************** |
715 | // |
716 | ************************************************************************/ |
717 | static int lzo1x_999_compress_internal(const uint8_t *in, unsigned in_len, |
718 | uint8_t *out, unsigned *out_len, |
719 | void *wrkmem, |
720 | unsigned good_length, |
721 | unsigned max_lazy, |
722 | unsigned max_chain, |
723 | uint32_t use_best_off) |
724 | { |
725 | uint8_t *op; |
726 | const uint8_t *ii; |
727 | unsigned lit; |
728 | unsigned m_len, m_off; |
729 | lzo1x_999_t cc; |
730 | lzo1x_999_t *const c = &cc; |
731 | const lzo_swd_p swd = (lzo_swd_p) wrkmem; |
732 | int r; |
733 | |
734 | c->init = 0; |
735 | c->ip = c->in = in; |
736 | c->in_end = in + in_len; |
737 | c->out = out; |
738 | |
739 | op = out; |
740 | ii = c->ip; /* point to start of literal run */ |
741 | lit = 0; |
742 | c->r1_lit = 0; |
743 | |
744 | r = init_match(c, swd, use_best_off); |
745 | if (r != 0) |
746 | return r; |
747 | swd->max_chain = max_chain; |
748 | |
749 | r = find_match(c, swd, 0, 0); |
750 | if (r != 0) |
751 | return r; |
752 | |
753 | while (c->look > 0) { |
754 | unsigned ahead; |
755 | unsigned max_ahead; |
756 | int l1, l2, l3; |
757 | |
758 | m_len = c->m_len; |
759 | m_off = c->m_off; |
760 | |
761 | assert(c->bp == c->ip - c->look); |
762 | assert(c->bp >= in); |
763 | if (lit == 0) |
764 | ii = c->bp; |
765 | assert(ii + lit == c->bp); |
766 | assert(swd->b_char == *(c->bp)); |
767 | |
768 | if (m_len < 2 |
769 | || (m_len == 2 && (m_off > M1_MAX_OFFSET || lit == 0 || lit >= 4)) |
770 | /* Do not accept this match for compressed-data compatibility |
771 | * with LZO v1.01 and before |
772 | * [ might be a problem for decompress() and optimize() ] |
773 | */ |
774 | || (m_len == 2 && op == out) |
775 | || (op == out && lit == 0) |
776 | ) { |
777 | /* a literal */ |
778 | m_len = 0; |
779 | } |
780 | else if (m_len == M2_MIN_LEN) { |
781 | /* compression ratio improves if we code a literal in some cases */ |
782 | if (m_off > MX_MAX_OFFSET && lit >= 4) |
783 | m_len = 0; |
784 | } |
785 | |
786 | if (m_len == 0) { |
787 | /* a literal */ |
788 | lit++; |
789 | swd->max_chain = max_chain; |
790 | r = find_match(c, swd, 1, 0); |
791 | assert(r == 0); |
792 | continue; |
793 | } |
794 | |
795 | /* a match */ |
796 | #if defined(SWD_BEST_OFF) |
797 | if (swd->use_best_off) |
798 | better_match(swd, &m_len, &m_off); |
799 | #endif |
800 | |
801 | /* shall we try a lazy match ? */ |
802 | ahead = 0; |
803 | if (m_len >= max_lazy) { |
804 | /* no */ |
805 | l1 = 0; |
806 | max_ahead = 0; |
807 | } else { |
808 | /* yes, try a lazy match */ |
809 | l1 = len_of_coded_match(m_len, m_off, lit); |
810 | assert(l1 > 0); |
811 | max_ahead = LZO_MIN(2, (unsigned)l1 - 1); |
812 | } |
813 | |
814 | |
815 | while (ahead < max_ahead && c->look > m_len) { |
816 | int lazy_match_min_gain; |
817 | |
818 | if (m_len >= good_length) |
819 | swd->max_chain = max_chain >> 2; |
820 | else |
821 | swd->max_chain = max_chain; |
822 | r = find_match(c, swd, 1, 0); |
823 | ahead++; |
824 | |
825 | assert(r == 0); |
826 | assert(c->look > 0); |
827 | assert(ii + lit + ahead == c->bp); |
828 | |
829 | if (c->m_len < m_len) |
830 | continue; |
831 | if (c->m_len == m_len && c->m_off >= m_off) |
832 | continue; |
833 | #if defined(SWD_BEST_OFF) |
834 | if (swd->use_best_off) |
835 | better_match(swd, &c->m_len, &c->m_off); |
836 | #endif |
837 | l2 = len_of_coded_match(c->m_len, c->m_off, lit+ahead); |
838 | if (l2 < 0) |
839 | continue; |
840 | |
841 | /* compressed-data compatibility [see above] */ |
842 | l3 = (op == out) ? -1 : len_of_coded_match(ahead, m_off, lit); |
843 | |
844 | lazy_match_min_gain = min_gain(ahead, lit, lit+ahead, l1, l2, l3); |
845 | if (c->m_len >= m_len + lazy_match_min_gain) { |
846 | if (l3 > 0) { |
847 | /* code previous run */ |
848 | op = code_run(c, op, ii, lit); |
849 | lit = 0; |
850 | /* code shortened match */ |
851 | op = code_match(c, op, ahead, m_off); |
852 | } else { |
853 | lit += ahead; |
854 | assert(ii + lit == c->bp); |
855 | } |
856 | goto lazy_match_done; |
857 | } |
858 | } |
859 | |
860 | assert(ii + lit + ahead == c->bp); |
861 | |
862 | /* 1 - code run */ |
863 | op = code_run(c, op, ii, lit); |
864 | lit = 0; |
865 | |
866 | /* 2 - code match */ |
867 | op = code_match(c, op, m_len, m_off); |
868 | swd->max_chain = max_chain; |
869 | r = find_match(c, swd, m_len, 1+ahead); |
870 | assert(r == 0); |
871 | |
872 | lazy_match_done: ; |
873 | } |
874 | |
875 | /* store final run */ |
876 | if (lit > 0) |
877 | op = STORE_RUN(c, op, ii, lit); |
878 | |
879 | #if defined(LZO_EOF_CODE) |
880 | *op++ = M4_MARKER | 1; |
881 | *op++ = 0; |
882 | *op++ = 0; |
883 | #endif |
884 | |
885 | *out_len = op - out; |
886 | |
887 | return LZO_E_OK; |
888 | } |
889 | |
890 | |
891 | /*********************************************************************** |
892 | // |
893 | ************************************************************************/ |
894 | int lzo1x_999_compress_level(const uint8_t *in, unsigned in_len, |
895 | uint8_t *out, unsigned *out_len, |
896 | void *wrkmem, |
897 | int compression_level) |
898 | { |
899 | static const struct { |
900 | uint16_t good_length; |
901 | uint16_t max_lazy; |
902 | uint16_t max_chain; |
903 | uint16_t use_best_off; |
904 | } c[3] = { |
905 | { 8, 32, 256, 0 }, |
906 | { 32, 128, 2048, 1 }, |
907 | { SWD_F, SWD_F, 4096, 1 } /* max. compression */ |
908 | }; |
909 | |
910 | if (compression_level < 7 || compression_level > 9) |
911 | return LZO_E_ERROR; |
912 | |
913 | compression_level -= 7; |
914 | return lzo1x_999_compress_internal(in, in_len, out, out_len, wrkmem, |
915 | c[compression_level].good_length, |
916 | c[compression_level].max_lazy, |
917 | c[compression_level].max_chain, |
918 | c[compression_level].use_best_off); |
919 | } |
920 |