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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 | /* * LZ4 - Fast LZ compression algorithm * Copyright (C) 2011-2012, Yann Collet. * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * You can contact the author at : * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html * - LZ4 source repository : http://code.google.com/p/lz4/ * * Changed for kernel use by: * Chanho Min <chanho.min@lge.com> */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/lz4.h> #include <asm/unaligned.h> #include "lz4defs.h" /* * LZ4_compressCtx : * ----------------- * Compress 'isize' bytes from 'source' into an output buffer 'dest' of * maximum size 'maxOutputSize'. * If it cannot achieve it, compression * will stop, and result of the function will be zero. * return : the number of bytes written in buffer 'dest', or 0 if the * compression fails */ static inline int lz4_compressctx(void *ctx, const char *source, char *dest, int isize, int maxoutputsize) { HTYPE *hashtable = (HTYPE *)ctx; const u8 *ip = (u8 *)source; #if LZ4_ARCH64 const BYTE * const base = ip; #else const int base = 0; #endif const u8 *anchor = ip; const u8 *const iend = ip + isize; const u8 *const mflimit = iend - MFLIMIT; #define MATCHLIMIT (iend - LASTLITERALS) u8 *op = (u8 *) dest; u8 *const oend = op + maxoutputsize; int length; const int skipstrength = SKIPSTRENGTH; u32 forwardh; int lastrun; /* Init */ if (isize < MINLENGTH) goto _last_literals; memset((void *)hashtable, 0, LZ4_MEM_COMPRESS); /* First Byte */ hashtable[LZ4_HASH_VALUE(ip)] = ip - base; ip++; forwardh = LZ4_HASH_VALUE(ip); /* Main Loop */ for (;;) { int findmatchattempts = (1U << skipstrength) + 3; const u8 *forwardip = ip; const u8 *ref; u8 *token; /* Find a match */ do { u32 h = forwardh; int step = findmatchattempts++ >> skipstrength; ip = forwardip; forwardip = ip + step; if (unlikely(forwardip > mflimit)) goto _last_literals; forwardh = LZ4_HASH_VALUE(forwardip); ref = base + hashtable[h]; hashtable[h] = ip - base; } while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip))); /* Catch up */ while ((ip > anchor) && (ref > (u8 *)source) && unlikely(ip[-1] == ref[-1])) { ip--; ref--; } /* Encode Literal length */ length = (int)(ip - anchor); token = op++; /* check output limit */ if (unlikely(op + length + (2 + 1 + LASTLITERALS) + (length >> 8) > oend)) return 0; if (length >= (int)RUN_MASK) { int len; *token = (RUN_MASK << ML_BITS); len = length - RUN_MASK; for (; len > 254 ; len -= 255) *op++ = 255; *op++ = (u8)len; } else *token = (length << ML_BITS); /* Copy Literals */ LZ4_BLINDCOPY(anchor, op, length); _next_match: /* Encode Offset */ LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref)); /* Start Counting */ ip += MINMATCH; /* MinMatch verified */ ref += MINMATCH; anchor = ip; while (likely(ip < MATCHLIMIT - (STEPSIZE - 1))) { #if LZ4_ARCH64 u64 diff = A64(ref) ^ A64(ip); #else u32 diff = A32(ref) ^ A32(ip); #endif if (!diff) { ip += STEPSIZE; ref += STEPSIZE; continue; } ip += LZ4_NBCOMMONBYTES(diff); goto _endcount; } #if LZ4_ARCH64 if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) { ip += 4; ref += 4; } #endif if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) { ip += 2; ref += 2; } if ((ip < MATCHLIMIT) && (*ref == *ip)) ip++; _endcount: /* Encode MatchLength */ length = (int)(ip - anchor); /* Check output limit */ if (unlikely(op + (1 + LASTLITERALS) + (length >> 8) > oend)) return 0; if (length >= (int)ML_MASK) { *token += ML_MASK; length -= ML_MASK; for (; length > 509 ; length -= 510) { *op++ = 255; *op++ = 255; } if (length > 254) { length -= 255; *op++ = 255; } *op++ = (u8)length; } else *token += length; /* Test end of chunk */ if (ip > mflimit) { anchor = ip; break; } /* Fill table */ hashtable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base; /* Test next position */ ref = base + hashtable[LZ4_HASH_VALUE(ip)]; hashtable[LZ4_HASH_VALUE(ip)] = ip - base; if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) { token = op++; *token = 0; goto _next_match; } /* Prepare next loop */ anchor = ip++; forwardh = LZ4_HASH_VALUE(ip); } _last_literals: /* Encode Last Literals */ lastrun = (int)(iend - anchor); if (((char *)op - dest) + lastrun + 1 + ((lastrun + 255 - RUN_MASK) / 255) > (u32)maxoutputsize) return 0; if (lastrun >= (int)RUN_MASK) { *op++ = (RUN_MASK << ML_BITS); lastrun -= RUN_MASK; for (; lastrun > 254 ; lastrun -= 255) *op++ = 255; *op++ = (u8)lastrun; } else *op++ = (lastrun << ML_BITS); memcpy(op, anchor, iend - anchor); op += iend - anchor; /* End */ return (int)(((char *)op) - dest); } static inline int lz4_compress64kctx(void *ctx, const char *source, char *dest, int isize, int maxoutputsize) { u16 *hashtable = (u16 *)ctx; const u8 *ip = (u8 *) source; const u8 *anchor = ip; const u8 *const base = ip; const u8 *const iend = ip + isize; const u8 *const mflimit = iend - MFLIMIT; #define MATCHLIMIT (iend - LASTLITERALS) u8 *op = (u8 *) dest; u8 *const oend = op + maxoutputsize; int len, length; const int skipstrength = SKIPSTRENGTH; u32 forwardh; int lastrun; /* Init */ if (isize < MINLENGTH) goto _last_literals; memset((void *)hashtable, 0, LZ4_MEM_COMPRESS); /* First Byte */ ip++; forwardh = LZ4_HASH64K_VALUE(ip); /* Main Loop */ for (;;) { int findmatchattempts = (1U << skipstrength) + 3; const u8 *forwardip = ip; const u8 *ref; u8 *token; /* Find a match */ do { u32 h = forwardh; int step = findmatchattempts++ >> skipstrength; ip = forwardip; forwardip = ip + step; if (forwardip > mflimit) goto _last_literals; forwardh = LZ4_HASH64K_VALUE(forwardip); ref = base + hashtable[h]; hashtable[h] = (u16)(ip - base); } while (A32(ref) != A32(ip)); /* Catch up */ while ((ip > anchor) && (ref > (u8 *)source) && (ip[-1] == ref[-1])) { ip--; ref--; } /* Encode Literal length */ length = (int)(ip - anchor); token = op++; /* Check output limit */ if (unlikely(op + length + (2 + 1 + LASTLITERALS) + (length >> 8) > oend)) return 0; if (length >= (int)RUN_MASK) { *token = (RUN_MASK << ML_BITS); len = length - RUN_MASK; for (; len > 254 ; len -= 255) *op++ = 255; *op++ = (u8)len; } else *token = (length << ML_BITS); /* Copy Literals */ LZ4_BLINDCOPY(anchor, op, length); _next_match: /* Encode Offset */ LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref)); /* Start Counting */ ip += MINMATCH; /* MinMatch verified */ ref += MINMATCH; anchor = ip; while (ip < MATCHLIMIT - (STEPSIZE - 1)) { #if LZ4_ARCH64 u64 diff = A64(ref) ^ A64(ip); #else u32 diff = A32(ref) ^ A32(ip); #endif if (!diff) { ip += STEPSIZE; ref += STEPSIZE; continue; } ip += LZ4_NBCOMMONBYTES(diff); goto _endcount; } #if LZ4_ARCH64 if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) { ip += 4; ref += 4; } #endif if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) { ip += 2; ref += 2; } if ((ip < MATCHLIMIT) && (*ref == *ip)) ip++; _endcount: /* Encode MatchLength */ len = (int)(ip - anchor); /* Check output limit */ if (unlikely(op + (1 + LASTLITERALS) + (len >> 8) > oend)) return 0; if (len >= (int)ML_MASK) { *token += ML_MASK; len -= ML_MASK; for (; len > 509 ; len -= 510) { *op++ = 255; *op++ = 255; } if (len > 254) { len -= 255; *op++ = 255; } *op++ = (u8)len; } else *token += len; /* Test end of chunk */ if (ip > mflimit) { anchor = ip; break; } /* Fill table */ hashtable[LZ4_HASH64K_VALUE(ip-2)] = (u16)(ip - 2 - base); /* Test next position */ ref = base + hashtable[LZ4_HASH64K_VALUE(ip)]; hashtable[LZ4_HASH64K_VALUE(ip)] = (u16)(ip - base); if (A32(ref) == A32(ip)) { token = op++; *token = 0; goto _next_match; } /* Prepare next loop */ anchor = ip++; forwardh = LZ4_HASH64K_VALUE(ip); } _last_literals: /* Encode Last Literals */ lastrun = (int)(iend - anchor); if (op + lastrun + 1 + (lastrun - RUN_MASK + 255) / 255 > oend) return 0; if (lastrun >= (int)RUN_MASK) { *op++ = (RUN_MASK << ML_BITS); lastrun -= RUN_MASK; for (; lastrun > 254 ; lastrun -= 255) *op++ = 255; *op++ = (u8)lastrun; } else *op++ = (lastrun << ML_BITS); memcpy(op, anchor, iend - anchor); op += iend - anchor; /* End */ return (int)(((char *)op) - dest); } int lz4_compress(const unsigned char *src, size_t src_len, unsigned char *dst, size_t *dst_len, void *wrkmem) { int ret = -1; int out_len = 0; if (src_len < LZ4_64KLIMIT) out_len = lz4_compress64kctx(wrkmem, src, dst, src_len, lz4_compressbound(src_len)); else out_len = lz4_compressctx(wrkmem, src, dst, src_len, lz4_compressbound(src_len)); if (out_len < 0) goto exit; *dst_len = out_len; return 0; exit: return ret; } EXPORT_SYMBOL_GPL(lz4_compress); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("LZ4 compressor"); |