Annotation of /trunk/mkinitrd-magellan/busybox/archival/lzo1x_9x.c
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Wed Aug 18 21:56:57 2010 UTC (13 years, 9 months ago) by niro
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Wed Aug 18 21:56:57 2010 UTC (13 years, 9 months ago) by niro
File MIME type: text/plain
File size: 21043 byte(s)
-updated to busybox-1.17.1
1 | niro | 984 | /* 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 | niro | 1123 | memcpy(&s->b[s->ip], s->c->ip, s->look); |
180 | niro | 984 | 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 | niro | 1123 | key = HEAD3(s->b, s->bp); |
260 | s->succ3[s->bp] = s_get_head3(s, key); | ||
261 | niro | 984 | 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 | niro | 1123 | key = HEAD2(s->b, s->bp); |
269 | niro | 984 | 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 | niro | 1123 | 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 | niro | 984 | unsigned i; |
307 | niro | 1123 | assert(lzo_memcmp(bp, &b[node], 3) == 0); |
308 | niro | 984 | |
309 | p1 += 2; p2 += 2; | ||
310 | do {} while (++p1 < px && *p1 == *++p2); | ||
311 | i = p1-bp; | ||
312 | |||
313 | niro | 1123 | assert(lzo_memcmp(bp, &b[node], i) == 0); |
314 | niro | 984 | |
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 | niro | 1123 | key = s->head2[HEAD2(s->b, s->bp)]; |
350 | niro | 984 | if (key == NIL2) |
351 | return 0; | ||
352 | niro | 1123 | assert(lzo_memcmp(&s->b[s->bp], &s->b[key], 2) == 0); |
353 | niro | 984 | #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 | niro | 1123 | node = s->succ3[s->bp] = s_get_head3(s, key); |
382 | niro | 984 | 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 | niro | 1123 | swd_search(s, node, cnt); |
401 | niro | 984 | 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 | niro | 1123 | for (i = 2; i < SWD_BEST_OFF; i++) { |
409 | niro | 984 | if (s->best_pos[i] > 0) |
410 | niro | 1123 | s->best_off[i] = swd_pos2off(s, s->best_pos[i]-1); |
411 | niro | 984 | else |
412 | s->best_off[i] = 0; | ||
413 | niro | 1123 | } |
414 | niro | 984 | } |
415 | #endif | ||
416 | } | ||
417 | |||
418 | swd_remove_node(s,s->rp); | ||
419 | |||
420 | #ifdef HEAD2 | ||
421 | /* add bp into HEAD2 */ | ||
422 | niro | 1123 | key = HEAD2(s->b, s->bp); |
423 | niro | 984 | 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 | niro | 1123 | memset(s->best_pos, 0, sizeof(s->best_pos)); |
473 | niro | 984 | #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 | niro | 1123 | assert(c->r1_lit > 0); |
511 | assert(c->r1_lit < 4); | ||
512 | niro | 984 | 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 | niro | 1123 | while (m_len > 255) { |
536 | m_len -= 255; | ||
537 | *op++ = 0; | ||
538 | } | ||
539 | niro | 984 | 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 | niro | 1123 | assert(m_off > 0x4000); |
549 | assert(m_off <= 0xbfff); | ||
550 | niro | 984 | 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 | niro | 1123 | while (m_len > 255) { |
558 | m_len -= 255; | ||
559 | *op++ = 0; | ||
560 | } | ||
561 | niro | 984 | 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 | niro | 1123 | op = STORE_RUN(c, op, ii, lit); |
604 | niro | 984 | } 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 | niro | 1123 | 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 | niro | 984 | |
695 | /* M4 -> M2 */ | ||
696 | niro | 1123 | 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 | niro | 984 | /* M4 -> M3 */ |
705 | niro | 1123 | 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 | niro | 984 | } |
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 | niro | 1123 | lzo1x_999_t *const c = &cc; |
734 | const lzo_swd_p swd = (lzo_swd_p) wrkmem; | ||
735 | niro | 984 | 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 | niro | 1123 | 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 | niro | 984 | 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 | niro | 1123 | r = find_match(c, swd, 1, 0); |
794 | niro | 984 | assert(r == 0); |
795 | continue; | ||
796 | } | ||
797 | |||
798 | /* a match */ | ||
799 | #if defined(SWD_BEST_OFF) | ||
800 | if (swd->use_best_off) | ||
801 | niro | 1123 | better_match(swd, &m_len, &m_off); |
802 | niro | 984 | #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 | niro | 1123 | l1 = len_of_coded_match(m_len, m_off, lit); |
813 | niro | 984 | 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 | niro | 1123 | r = find_match(c, swd, 1, 0); |
826 | niro | 984 | 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 | niro | 1123 | better_match(swd, &c->m_len, &c->m_off); |
839 | niro | 984 | #endif |
840 | niro | 1123 | l2 = len_of_coded_match(c->m_len, c->m_off, lit+ahead); |
841 | niro | 984 | if (l2 < 0) |
842 | continue; | ||
843 | |||
844 | /* compressed-data compatibility [see above] */ | ||
845 | niro | 1123 | l3 = (op == out) ? -1 : len_of_coded_match(ahead, m_off, lit); |
846 | niro | 984 | |
847 | niro | 1123 | lazy_match_min_gain = min_gain(ahead, lit, lit+ahead, l1, l2, l3); |
848 | niro | 984 | if (c->m_len >= m_len + lazy_match_min_gain) { |
849 | if (l3 > 0) { | ||
850 | /* code previous run */ | ||
851 | niro | 1123 | op = code_run(c, op, ii, lit); |
852 | niro | 984 | lit = 0; |
853 | /* code shortened match */ | ||
854 | niro | 1123 | op = code_match(c, op, ahead, m_off); |
855 | niro | 984 | } 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 | niro | 1123 | op = code_run(c, op, ii, lit); |
867 | niro | 984 | lit = 0; |
868 | |||
869 | /* 2 - code match */ | ||
870 | niro | 1123 | op = code_match(c, op, m_len, m_off); |
871 | niro | 984 | swd->max_chain = max_chain; |
872 | niro | 1123 | r = find_match(c, swd, m_len, 1+ahead); |
873 | niro | 984 | assert(r == 0); |
874 | |||
875 | lazy_match_done: ; | ||
876 | } | ||
877 | |||
878 | /* store final run */ | ||
879 | if (lit > 0) | ||
880 | niro | 1123 | op = STORE_RUN(c, op, ii, lit); |
881 | niro | 984 | |
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 | } |