1 /* 2 * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de> 3 * 4 * Redistribution and use in source and binary forms, with or without modifica- 5 * tion, are permitted provided that the following conditions are met: 6 * 7 * 1. Redistributions of source code must retain the above copyright notice, 8 * this list of conditions and the following disclaimer. 9 * 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 15 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- 16 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 17 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- 18 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 20 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 21 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- 22 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 23 * OF THE POSSIBILITY OF SUCH DAMAGE. 24 * 25 * Alternatively, the contents of this file may be used under the terms of 26 * the GNU General Public License ("GPL") version 2 or any later version, 27 * in which case the provisions of the GPL are applicable instead of 28 * the above. If you wish to allow the use of your version of this file 29 * only under the terms of the GPL and not to allow others to use your 30 * version of this file under the BSD license, indicate your decision 31 * by deleting the provisions above and replace them with the notice 32 * and other provisions required by the GPL. If you do not delete the 33 * provisions above, a recipient may use your version of this file under 34 * either the BSD or the GPL. 35 */ 36 37 #include "lzf.h" 38 39 #define HSIZE (1 << (HLOG)) 40 41 /* 42 * don't play with this unless you benchmark! 43 * decompression is not dependent on the hash function 44 * the hashing function might seem strange, just believe me 45 * it works ;) 46 */ 47 #ifndef FRST 48 # define FRST(p) (((p[0]) << 8) | p[1]) 49 # define NEXT(v,p) (((v) << 8) | p[2]) 50 # if ULTRA_FAST 51 # define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1)) 52 # elif VERY_FAST 53 # define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) 54 # else 55 # define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) 56 # endif 57 #endif 58 /* 59 * IDX works because it is very similar to a multiplicative hash, e.g. 60 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) 61 * the latter is also quite fast on newer CPUs, and compresses similarly. 62 * 63 * the next one is also quite good, albeit slow ;) 64 * (int)(cos(h & 0xffffff) * 1e6) 65 */ 66 67 #if 0 68 /* original lzv-like hash function, much worse and thus slower */ 69 # define FRST(p) (p[0] << 5) ^ p[1] 70 # define NEXT(v,p) ((v) << 5) ^ p[2] 71 # define IDX(h) ((h) & (HSIZE - 1)) 72 #endif 73 74 #define MAX_LIT (1 << 5) 75 #define MAX_OFF (1 << 13) 76 #define MAX_REF ((1 << 8) + (1 << 3)) 77 78 #if __GNUC__ >= 3 79 # define expect(expr,value) __builtin_expect ((expr),(value)) 80 # define inline inline 81 #else 82 # define expect(expr,value) (expr) 83 # define inline static 84 #endif 85 86 #define expect_false(expr) expect ((expr) != 0, 0) 87 #define expect_true(expr) expect ((expr) != 0, 1) 88 89 /* 90 * compressed format 91 * 92 * 000LLLLL <L+1> ; literal 93 * LLLooooo oooooooo ; backref L 94 * 111ooooo LLLLLLLL oooooooo ; backref L+7 95 * 96 */ 97 98 unsigned int 99 lzf_compress (const void *const in_data, unsigned int in_len, 100 void *out_data, unsigned int out_len 101 #if LZF_STATE_ARG 102 , LZF_STATE htab 103 #endif 104 ) 105 { 106 #if !LZF_STATE_ARG 107 LZF_STATE htab; 108 #endif 109 const u8 **hslot; 110 const u8 *ip = (const u8 *)in_data; 111 u8 *op = (u8 *)out_data; 112 const u8 *in_end = ip + in_len; 113 u8 *out_end = op + out_len; 114 const u8 *ref; 115 116 /* off requires a type wide enough to hold a general pointer difference. 117 * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only 118 * works for differences within a single object). We also assume that no 119 * no bit pattern traps. Since the only platform that is both non-POSIX 120 * and fails to support both assumptions is windows 64 bit, we make a 121 * special workaround for it. 122 */ 123 #if defined (WIN32) && defined (_M_X64) 124 unsigned _int64 off; /* workaround for missing POSIX compliance */ 125 #else 126 unsigned long off; 127 #endif 128 unsigned int hval; 129 int lit; 130 131 if (!in_len || !out_len) 132 return 0; 133 134 #if INIT_HTAB 135 memset (htab, 0, sizeof (htab)); 136 # if 0 137 for (hslot = htab; hslot < htab + HSIZE; hslot++) 138 *hslot++ = ip; 139 # endif 140 #endif 141 142 lit = 0; op++; /* start run */ 143 144 hval = FRST (ip); 145 while (ip < in_end - 2) 146 { 147 hval = NEXT (hval, ip); 148 hslot = htab + IDX (hval); 149 ref = *hslot; *hslot = ip; 150 151 if (1 152 #if INIT_HTAB 153 && ref < ip /* the next test will actually take care of this, but this is faster */ 154 #endif 155 && (off = ip - ref - 1) < MAX_OFF 156 && ip + 4 < in_end 157 && ref > (const u8 *)in_data 158 #if STRICT_ALIGN 159 && ref[0] == ip[0] 160 && ref[1] == ip[1] 161 && ref[2] == ip[2] 162 #else 163 && *(const u16 *)ref == *(const u16 *)ip 164 && ref[2] == ip[2] 165 #endif 166 ) 167 { 168 /* match found at *ref++ */ 169 unsigned int len = 2; 170 unsigned int maxlen = in_end - ip - len; 171 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 172 173 if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */ 174 if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */ 175 return 0; 176 177 op [- lit - 1] = lit - 1; /* stop run */ 178 op -= !lit; /* undo run if length is zero */ 179 180 for (;;) 181 { 182 if (expect_true (maxlen > 16)) 183 { 184 len++; if (ref [len] != ip [len]) break; 185 len++; if (ref [len] != ip [len]) break; 186 len++; if (ref [len] != ip [len]) break; 187 len++; if (ref [len] != ip [len]) break; 188 189 len++; if (ref [len] != ip [len]) break; 190 len++; if (ref [len] != ip [len]) break; 191 len++; if (ref [len] != ip [len]) break; 192 len++; if (ref [len] != ip [len]) break; 193 194 len++; if (ref [len] != ip [len]) break; 195 len++; if (ref [len] != ip [len]) break; 196 len++; if (ref [len] != ip [len]) break; 197 len++; if (ref [len] != ip [len]) break; 198 199 len++; if (ref [len] != ip [len]) break; 200 len++; if (ref [len] != ip [len]) break; 201 len++; if (ref [len] != ip [len]) break; 202 len++; if (ref [len] != ip [len]) break; 203 } 204 205 do 206 len++; 207 while (len < maxlen && ref[len] == ip[len]); 208 209 break; 210 } 211 212 len -= 2; /* len is now #octets - 1 */ 213 ip++; 214 215 if (len < 7) 216 { 217 *op++ = (off >> 8) + (len << 5); 218 } 219 else 220 { 221 *op++ = (off >> 8) + ( 7 << 5); 222 *op++ = len - 7; 223 } 224 225 *op++ = off; 226 lit = 0; op++; /* start run */ 227 228 ip += len + 1; 229 230 if (expect_false (ip >= in_end - 2)) 231 break; 232 233 #if ULTRA_FAST || VERY_FAST 234 --ip; 235 # if VERY_FAST && !ULTRA_FAST 236 --ip; 237 # endif 238 hval = FRST (ip); 239 240 hval = NEXT (hval, ip); 241 htab[IDX (hval)] = ip; 242 ip++; 243 244 # if VERY_FAST && !ULTRA_FAST 245 hval = NEXT (hval, ip); 246 htab[IDX (hval)] = ip; 247 ip++; 248 # endif 249 #else 250 ip -= len + 1; 251 252 do 253 { 254 hval = NEXT (hval, ip); 255 htab[IDX (hval)] = ip; 256 ip++; 257 } 258 while (len--); 259 #endif 260 } 261 else 262 { 263 /* one more literal byte we must copy */ 264 if (expect_false (op >= out_end)) 265 return 0; 266 267 lit++; *op++ = *ip++; 268 269 if (expect_false (lit == MAX_LIT)) 270 { 271 op [- lit - 1] = lit - 1; /* stop run */ 272 lit = 0; op++; /* start run */ 273 } 274 } 275 } 276 277 if (op + 3 > out_end) /* at most 3 bytes can be missing here */ 278 return 0; 279 280 while (ip < in_end) 281 { 282 lit++; *op++ = *ip++; 283 284 if (expect_false (lit == MAX_LIT)) 285 { 286 op [- lit - 1] = lit - 1; /* stop run */ 287 lit = 0; op++; /* start run */ 288 } 289 } 290 291 op [- lit - 1] = lit - 1; /* end run */ 292 op -= !lit; /* undo run if length is zero */ 293 294 return op - (u8 *)out_data; 295 } 296 297 #if AVOID_ERRNO 298 # define SET_ERRNO(n) 299 #else 300 # include <errno.h> 301 # define SET_ERRNO(n) errno = (n) 302 #endif 303 304 #if (__i386 || __amd64) && __GNUC__ >= 3 305 # define lzf_movsb(dst, src, len) \ 306 asm ("rep movsb" \ 307 : "=D" (dst), "=S" (src), "=c" (len) \ 308 : "0" (dst), "1" (src), "2" (len)); 309 #endif 310 311 unsigned int 312 lzf_decompress (const void *const in_data, unsigned int in_len, 313 void *out_data, unsigned int out_len) 314 { 315 u8 const *ip = (const u8 *)in_data; 316 u8 *op = (u8 *)out_data; 317 u8 const *const in_end = ip + in_len; 318 u8 *const out_end = op + out_len; 319 320 do 321 { 322 unsigned int ctrl = *ip++; 323 324 if (ctrl < (1 << 5)) /* literal run */ 325 { 326 ctrl++; 327 328 if (op + ctrl > out_end) 329 { 330 SET_ERRNO (E2BIG); 331 return 0; 332 } 333 334 #if CHECK_INPUT 335 if (ip + ctrl > in_end) 336 { 337 SET_ERRNO (EINVAL); 338 return 0; 339 } 340 #endif 341 342 #ifdef lzf_movsb 343 lzf_movsb (op, ip, ctrl); 344 #else 345 do 346 *op++ = *ip++; 347 while (--ctrl); 348 #endif 349 } 350 else /* back reference */ 351 { 352 unsigned int len = ctrl >> 5; 353 354 u8 *ref = op - ((ctrl & 0x1f) << 8) - 1; 355 356 #if CHECK_INPUT 357 if (ip >= in_end) 358 { 359 SET_ERRNO (EINVAL); 360 return 0; 361 } 362 #endif 363 if (len == 7) 364 { 365 len += *ip++; 366 #if CHECK_INPUT 367 if (ip >= in_end) 368 { 369 SET_ERRNO (EINVAL); 370 return 0; 371 } 372 #endif 373 } 374 375 ref -= *ip++; 376 377 if (op + len + 2 > out_end) 378 { 379 SET_ERRNO (E2BIG); 380 return 0; 381 } 382 383 if (ref < (u8 *)out_data) 384 { 385 SET_ERRNO (EINVAL); 386 return 0; 387 } 388 389 #ifdef lzf_movsb 390 len += 2; 391 lzf_movsb (op, ref, len); 392 #else 393 *op++ = *ref++; 394 *op++ = *ref++; 395 396 do 397 *op++ = *ref++; 398 while (--len); 399 #endif 400 } 401 } 402 while (ip < in_end); 403 404 return op - (u8 *)out_data; 405 } 406 407