Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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) |
Denys Vlasenko | 5117eff | 2013-10-16 14:21:20 +0200 | [diff] [blame] | 97 | # define HEAD2(b,p) (* (bb__aliased_uint16_t *) &(b[p])) |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 179 | memcpy(&s->b[s->ip], s->c->ip, s->look); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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 */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 259 | key = HEAD3(s->b, s->bp); |
| 260 | s->succ3[s->bp] = s_get_head3(s, key); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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 */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 268 | key = HEAD2(s->b, s->bp); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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 | |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 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 | ) { |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 306 | unsigned i; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 307 | assert(lzo_memcmp(bp, &b[node], 3) == 0); |
Denys Vlasenko | 9038d6f | 2009-07-15 20:02:19 +0200 | [diff] [blame] | 308 | |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 309 | p1 += 2; p2 += 2; |
| 310 | do {} while (++p1 < px && *p1 == *++p2); |
| 311 | i = p1-bp; |
| 312 | |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 313 | assert(lzo_memcmp(bp, &b[node], i) == 0); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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 | |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 349 | key = s->head2[HEAD2(s->b, s->bp)]; |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 350 | if (key == NIL2) |
| 351 | return 0; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 352 | assert(lzo_memcmp(&s->b[s->bp], &s->b[key], 2) == 0); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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); |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 381 | node = s->succ3[s->bp] = s_get_head3(s, key); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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) |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 400 | swd_search(s, node, cnt); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 408 | for (i = 2; i < SWD_BEST_OFF; i++) { |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 409 | if (s->best_pos[i] > 0) |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 410 | s->best_off[i] = swd_pos2off(s, s->best_pos[i]-1); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 411 | else |
| 412 | s->best_off[i] = 0; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 413 | } |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 414 | } |
| 415 | #endif |
| 416 | } |
| 417 | |
| 418 | swd_remove_node(s,s->rp); |
| 419 | |
| 420 | #ifdef HEAD2 |
| 421 | /* add bp into HEAD2 */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 422 | key = HEAD2(s->b, s->bp); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 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; |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 469 | #ifdef SWD_BEST_OFF |
| 470 | if (s->use_best_off) |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 471 | memset(s->best_pos, 0, sizeof(s->best_pos)); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 472 | #endif |
| 473 | swd_findbest(s); |
| 474 | c->m_len = s->m_len; |
| 475 | c->m_off = s->m_off; |
| 476 | |
| 477 | swd_getbyte(s); |
| 478 | |
| 479 | if (s->b_char < 0) { |
| 480 | c->look = 0; |
| 481 | c->m_len = 0; |
| 482 | } else { |
| 483 | c->look = s->look + 1; |
| 484 | } |
| 485 | c->bp = c->ip - c->look; |
| 486 | |
| 487 | return LZO_E_OK; |
| 488 | } |
| 489 | |
| 490 | /* this is a public functions, but there is no prototype in a header file */ |
| 491 | static int lzo1x_999_compress_internal(const uint8_t *in , unsigned in_len, |
| 492 | uint8_t *out, unsigned *out_len, |
| 493 | void *wrkmem, |
| 494 | unsigned good_length, |
| 495 | unsigned max_lazy, |
| 496 | unsigned max_chain, |
| 497 | uint32_t use_best_off); |
| 498 | |
| 499 | |
| 500 | /*********************************************************************** |
| 501 | // |
| 502 | ************************************************************************/ |
| 503 | static uint8_t *code_match(lzo1x_999_t *c, |
| 504 | uint8_t *op, unsigned m_len, unsigned m_off) |
| 505 | { |
| 506 | assert(op > c->out); |
| 507 | if (m_len == 2) { |
| 508 | assert(m_off <= M1_MAX_OFFSET); |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 509 | assert(c->r1_lit > 0); |
| 510 | assert(c->r1_lit < 4); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 511 | m_off -= 1; |
| 512 | *op++ = M1_MARKER | ((m_off & 3) << 2); |
| 513 | *op++ = m_off >> 2; |
| 514 | } else if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) { |
| 515 | assert(m_len >= 3); |
| 516 | m_off -= 1; |
| 517 | *op++ = ((m_len - 1) << 5) | ((m_off & 7) << 2); |
| 518 | *op++ = m_off >> 3; |
| 519 | assert(op[-2] >= M2_MARKER); |
| 520 | } else if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && c->r1_lit >= 4) { |
| 521 | assert(m_len == 3); |
| 522 | assert(m_off > M2_MAX_OFFSET); |
| 523 | m_off -= 1 + M2_MAX_OFFSET; |
| 524 | *op++ = M1_MARKER | ((m_off & 3) << 2); |
| 525 | *op++ = m_off >> 2; |
| 526 | } else if (m_off <= M3_MAX_OFFSET) { |
| 527 | assert(m_len >= 3); |
| 528 | m_off -= 1; |
| 529 | if (m_len <= M3_MAX_LEN) |
| 530 | *op++ = M3_MARKER | (m_len - 2); |
| 531 | else { |
| 532 | m_len -= M3_MAX_LEN; |
| 533 | *op++ = M3_MARKER | 0; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 534 | while (m_len > 255) { |
| 535 | m_len -= 255; |
| 536 | *op++ = 0; |
| 537 | } |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 538 | assert(m_len > 0); |
| 539 | *op++ = m_len; |
| 540 | } |
| 541 | *op++ = m_off << 2; |
| 542 | *op++ = m_off >> 6; |
| 543 | } else { |
| 544 | unsigned k; |
| 545 | |
| 546 | assert(m_len >= 3); |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 547 | assert(m_off > 0x4000); |
| 548 | assert(m_off <= 0xbfff); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 549 | m_off -= 0x4000; |
| 550 | k = (m_off & 0x4000) >> 11; |
| 551 | if (m_len <= M4_MAX_LEN) |
| 552 | *op++ = M4_MARKER | k | (m_len - 2); |
| 553 | else { |
| 554 | m_len -= M4_MAX_LEN; |
| 555 | *op++ = M4_MARKER | k | 0; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 556 | while (m_len > 255) { |
| 557 | m_len -= 255; |
| 558 | *op++ = 0; |
| 559 | } |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 560 | assert(m_len > 0); |
| 561 | *op++ = m_len; |
| 562 | } |
| 563 | *op++ = m_off << 2; |
| 564 | *op++ = m_off >> 6; |
| 565 | } |
| 566 | |
| 567 | return op; |
| 568 | } |
| 569 | |
| 570 | |
| 571 | static uint8_t *STORE_RUN(lzo1x_999_t *c, uint8_t *op, |
| 572 | const uint8_t *ii, unsigned t) |
| 573 | { |
| 574 | if (op == c->out && t <= 238) { |
| 575 | *op++ = 17 + t; |
| 576 | } else if (t <= 3) { |
| 577 | op[-2] |= t; |
| 578 | } else if (t <= 18) { |
| 579 | *op++ = t - 3; |
| 580 | } else { |
| 581 | unsigned tt = t - 18; |
| 582 | |
| 583 | *op++ = 0; |
| 584 | while (tt > 255) { |
| 585 | tt -= 255; |
| 586 | *op++ = 0; |
| 587 | } |
| 588 | assert(tt > 0); |
| 589 | *op++ = tt; |
| 590 | } |
| 591 | do *op++ = *ii++; while (--t > 0); |
| 592 | |
| 593 | return op; |
| 594 | } |
| 595 | |
| 596 | |
| 597 | static uint8_t *code_run(lzo1x_999_t *c, uint8_t *op, const uint8_t *ii, |
| 598 | unsigned lit) |
| 599 | { |
| 600 | if (lit > 0) { |
| 601 | assert(m_len >= 2); |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 602 | op = STORE_RUN(c, op, ii, lit); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 603 | } else { |
| 604 | assert(m_len >= 3); |
| 605 | } |
| 606 | c->r1_lit = lit; |
| 607 | |
| 608 | return op; |
| 609 | } |
| 610 | |
| 611 | |
| 612 | /*********************************************************************** |
| 613 | // |
| 614 | ************************************************************************/ |
| 615 | static int len_of_coded_match(unsigned m_len, unsigned m_off, unsigned lit) |
| 616 | { |
| 617 | int n = 4; |
| 618 | |
| 619 | if (m_len < 2) |
| 620 | return -1; |
| 621 | if (m_len == 2) |
| 622 | return (m_off <= M1_MAX_OFFSET && lit > 0 && lit < 4) ? 2 : -1; |
| 623 | if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) |
| 624 | return 2; |
| 625 | if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && lit >= 4) |
| 626 | return 2; |
| 627 | if (m_off <= M3_MAX_OFFSET) { |
| 628 | if (m_len <= M3_MAX_LEN) |
| 629 | return 3; |
| 630 | m_len -= M3_MAX_LEN; |
| 631 | } else if (m_off <= M4_MAX_OFFSET) { |
| 632 | if (m_len <= M4_MAX_LEN) |
| 633 | return 3; |
| 634 | m_len -= M4_MAX_LEN; |
| 635 | } else |
| 636 | return -1; |
| 637 | while (m_len > 255) { |
| 638 | m_len -= 255; |
| 639 | n++; |
| 640 | } |
| 641 | return n; |
| 642 | } |
| 643 | |
| 644 | |
| 645 | static int min_gain(unsigned ahead, unsigned lit1, |
Denys Vlasenko | 60cb48c | 2013-01-14 15:57:44 +0100 | [diff] [blame] | 646 | unsigned lit2, int l1, int l2, int l3) |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 647 | { |
| 648 | int lazy_match_min_gain = 0; |
| 649 | |
| 650 | assert (ahead >= 1); |
| 651 | lazy_match_min_gain += ahead; |
| 652 | |
| 653 | if (lit1 <= 3) |
| 654 | lazy_match_min_gain += (lit2 <= 3) ? 0 : 2; |
| 655 | else if (lit1 <= 18) |
| 656 | lazy_match_min_gain += (lit2 <= 18) ? 0 : 1; |
| 657 | |
| 658 | lazy_match_min_gain += (l2 - l1) * 2; |
| 659 | if (l3 > 0) |
| 660 | lazy_match_min_gain -= (ahead - l3) * 2; |
| 661 | |
| 662 | if (lazy_match_min_gain < 0) |
| 663 | lazy_match_min_gain = 0; |
| 664 | |
| 665 | return lazy_match_min_gain; |
| 666 | } |
| 667 | |
| 668 | |
| 669 | /*********************************************************************** |
| 670 | // |
| 671 | ************************************************************************/ |
| 672 | #if defined(SWD_BEST_OFF) |
| 673 | |
| 674 | static void better_match(const lzo_swd_p swd, |
Denys Vlasenko | 60cb48c | 2013-01-14 15:57:44 +0100 | [diff] [blame] | 675 | unsigned *m_len, unsigned *m_off) |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 676 | { |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 677 | if (*m_len <= M2_MIN_LEN) |
| 678 | return; |
| 679 | |
| 680 | if (*m_off <= M2_MAX_OFFSET) |
| 681 | return; |
| 682 | |
| 683 | /* M3/M4 -> M2 */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 684 | if (*m_off > M2_MAX_OFFSET |
| 685 | && *m_len >= M2_MIN_LEN + 1 && *m_len <= M2_MAX_LEN + 1 |
| 686 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M2_MAX_OFFSET |
| 687 | ) { |
| 688 | *m_len = *m_len - 1; |
| 689 | *m_off = swd->best_off[*m_len]; |
| 690 | return; |
| 691 | } |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 692 | |
| 693 | /* M4 -> M2 */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 694 | if (*m_off > M3_MAX_OFFSET |
| 695 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M2_MAX_LEN + 2 |
| 696 | && swd->best_off[*m_len-2] && swd->best_off[*m_len-2] <= M2_MAX_OFFSET |
| 697 | ) { |
| 698 | *m_len = *m_len - 2; |
| 699 | *m_off = swd->best_off[*m_len]; |
| 700 | return; |
| 701 | } |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 702 | /* M4 -> M3 */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 703 | if (*m_off > M3_MAX_OFFSET |
| 704 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M3_MAX_LEN + 1 |
| 705 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M3_MAX_OFFSET |
| 706 | ) { |
| 707 | *m_len = *m_len - 1; |
| 708 | *m_off = swd->best_off[*m_len]; |
| 709 | } |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 710 | } |
| 711 | |
| 712 | #endif |
| 713 | |
| 714 | |
| 715 | /*********************************************************************** |
| 716 | // |
| 717 | ************************************************************************/ |
| 718 | static int lzo1x_999_compress_internal(const uint8_t *in, unsigned in_len, |
| 719 | uint8_t *out, unsigned *out_len, |
| 720 | void *wrkmem, |
| 721 | unsigned good_length, |
| 722 | unsigned max_lazy, |
| 723 | unsigned max_chain, |
| 724 | uint32_t use_best_off) |
| 725 | { |
| 726 | uint8_t *op; |
| 727 | const uint8_t *ii; |
| 728 | unsigned lit; |
| 729 | unsigned m_len, m_off; |
| 730 | lzo1x_999_t cc; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 731 | lzo1x_999_t *const c = &cc; |
| 732 | const lzo_swd_p swd = (lzo_swd_p) wrkmem; |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 733 | int r; |
| 734 | |
| 735 | c->init = 0; |
| 736 | c->ip = c->in = in; |
| 737 | c->in_end = in + in_len; |
| 738 | c->out = out; |
| 739 | |
| 740 | op = out; |
| 741 | ii = c->ip; /* point to start of literal run */ |
| 742 | lit = 0; |
| 743 | c->r1_lit = 0; |
| 744 | |
| 745 | r = init_match(c, swd, use_best_off); |
| 746 | if (r != 0) |
| 747 | return r; |
| 748 | swd->max_chain = max_chain; |
| 749 | |
| 750 | r = find_match(c, swd, 0, 0); |
| 751 | if (r != 0) |
| 752 | return r; |
| 753 | |
| 754 | while (c->look > 0) { |
| 755 | unsigned ahead; |
| 756 | unsigned max_ahead; |
| 757 | int l1, l2, l3; |
| 758 | |
| 759 | m_len = c->m_len; |
| 760 | m_off = c->m_off; |
| 761 | |
| 762 | assert(c->bp == c->ip - c->look); |
| 763 | assert(c->bp >= in); |
| 764 | if (lit == 0) |
| 765 | ii = c->bp; |
| 766 | assert(ii + lit == c->bp); |
| 767 | assert(swd->b_char == *(c->bp)); |
| 768 | |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 769 | if (m_len < 2 |
| 770 | || (m_len == 2 && (m_off > M1_MAX_OFFSET || lit == 0 || lit >= 4)) |
| 771 | /* Do not accept this match for compressed-data compatibility |
| 772 | * with LZO v1.01 and before |
| 773 | * [ might be a problem for decompress() and optimize() ] |
| 774 | */ |
| 775 | || (m_len == 2 && op == out) |
| 776 | || (op == out && lit == 0) |
| 777 | ) { |
| 778 | /* a literal */ |
| 779 | m_len = 0; |
| 780 | } |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 781 | else if (m_len == M2_MIN_LEN) { |
| 782 | /* compression ratio improves if we code a literal in some cases */ |
| 783 | if (m_off > MX_MAX_OFFSET && lit >= 4) |
| 784 | m_len = 0; |
| 785 | } |
| 786 | |
| 787 | if (m_len == 0) { |
| 788 | /* a literal */ |
| 789 | lit++; |
| 790 | swd->max_chain = max_chain; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 791 | r = find_match(c, swd, 1, 0); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 792 | assert(r == 0); |
| 793 | continue; |
| 794 | } |
| 795 | |
| 796 | /* a match */ |
| 797 | #if defined(SWD_BEST_OFF) |
| 798 | if (swd->use_best_off) |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 799 | better_match(swd, &m_len, &m_off); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 800 | #endif |
| 801 | |
| 802 | /* shall we try a lazy match ? */ |
| 803 | ahead = 0; |
| 804 | if (m_len >= max_lazy) { |
| 805 | /* no */ |
| 806 | l1 = 0; |
| 807 | max_ahead = 0; |
| 808 | } else { |
| 809 | /* yes, try a lazy match */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 810 | l1 = len_of_coded_match(m_len, m_off, lit); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 811 | assert(l1 > 0); |
| 812 | max_ahead = LZO_MIN(2, (unsigned)l1 - 1); |
| 813 | } |
| 814 | |
| 815 | |
| 816 | while (ahead < max_ahead && c->look > m_len) { |
| 817 | int lazy_match_min_gain; |
| 818 | |
| 819 | if (m_len >= good_length) |
| 820 | swd->max_chain = max_chain >> 2; |
| 821 | else |
| 822 | swd->max_chain = max_chain; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 823 | r = find_match(c, swd, 1, 0); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 824 | ahead++; |
| 825 | |
| 826 | assert(r == 0); |
| 827 | assert(c->look > 0); |
| 828 | assert(ii + lit + ahead == c->bp); |
| 829 | |
| 830 | if (c->m_len < m_len) |
| 831 | continue; |
| 832 | if (c->m_len == m_len && c->m_off >= m_off) |
| 833 | continue; |
| 834 | #if defined(SWD_BEST_OFF) |
| 835 | if (swd->use_best_off) |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 836 | better_match(swd, &c->m_len, &c->m_off); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 837 | #endif |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 838 | l2 = len_of_coded_match(c->m_len, c->m_off, lit+ahead); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 839 | if (l2 < 0) |
| 840 | continue; |
| 841 | |
| 842 | /* compressed-data compatibility [see above] */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 843 | l3 = (op == out) ? -1 : len_of_coded_match(ahead, m_off, lit); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 844 | |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 845 | lazy_match_min_gain = min_gain(ahead, lit, lit+ahead, l1, l2, l3); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 846 | if (c->m_len >= m_len + lazy_match_min_gain) { |
| 847 | if (l3 > 0) { |
| 848 | /* code previous run */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 849 | op = code_run(c, op, ii, lit); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 850 | lit = 0; |
| 851 | /* code shortened match */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 852 | op = code_match(c, op, ahead, m_off); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 853 | } else { |
| 854 | lit += ahead; |
| 855 | assert(ii + lit == c->bp); |
| 856 | } |
| 857 | goto lazy_match_done; |
| 858 | } |
| 859 | } |
| 860 | |
| 861 | assert(ii + lit + ahead == c->bp); |
| 862 | |
| 863 | /* 1 - code run */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 864 | op = code_run(c, op, ii, lit); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 865 | lit = 0; |
| 866 | |
| 867 | /* 2 - code match */ |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 868 | op = code_match(c, op, m_len, m_off); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 869 | swd->max_chain = max_chain; |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 870 | r = find_match(c, swd, m_len, 1+ahead); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 871 | assert(r == 0); |
| 872 | |
| 873 | lazy_match_done: ; |
| 874 | } |
| 875 | |
| 876 | /* store final run */ |
| 877 | if (lit > 0) |
Denys Vlasenko | 6b9f163 | 2010-01-28 02:24:24 +0100 | [diff] [blame] | 878 | op = STORE_RUN(c, op, ii, lit); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 879 | |
| 880 | #if defined(LZO_EOF_CODE) |
| 881 | *op++ = M4_MARKER | 1; |
| 882 | *op++ = 0; |
| 883 | *op++ = 0; |
| 884 | #endif |
| 885 | |
| 886 | *out_len = op - out; |
| 887 | |
| 888 | return LZO_E_OK; |
| 889 | } |
| 890 | |
| 891 | |
| 892 | /*********************************************************************** |
| 893 | // |
| 894 | ************************************************************************/ |
| 895 | int lzo1x_999_compress_level(const uint8_t *in, unsigned in_len, |
| 896 | uint8_t *out, unsigned *out_len, |
| 897 | void *wrkmem, |
| 898 | int compression_level) |
| 899 | { |
| 900 | static const struct { |
| 901 | uint16_t good_length; |
| 902 | uint16_t max_lazy; |
| 903 | uint16_t max_chain; |
| 904 | uint16_t use_best_off; |
| 905 | } c[3] = { |
| 906 | { 8, 32, 256, 0 }, |
| 907 | { 32, 128, 2048, 1 }, |
| 908 | { SWD_F, SWD_F, 4096, 1 } /* max. compression */ |
| 909 | }; |
| 910 | |
| 911 | if (compression_level < 7 || compression_level > 9) |
| 912 | return LZO_E_ERROR; |
| 913 | |
| 914 | compression_level -= 7; |
| 915 | return lzo1x_999_compress_internal(in, in_len, out, out_len, wrkmem, |
Denys Vlasenko | 60cb48c | 2013-01-14 15:57:44 +0100 | [diff] [blame] | 916 | c[compression_level].good_length, |
| 917 | c[compression_level].max_lazy, |
| 918 | c[compression_level].max_chain, |
| 919 | c[compression_level].use_best_off); |
Denis Vlasenko | 052ad9a | 2009-04-29 12:01:51 +0000 | [diff] [blame] | 920 | } |