1 /* 2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 #include "zstd_compress_internal.h" 12 #include "zstd_double_fast.h" 13 14 15 void ZSTD_fillDoubleHashTable(ZSTD_matchState_t* ms, 16 ZSTD_compressionParameters const* cParams, 17 void const* end) 18 { 19 U32* const hashLarge = ms->hashTable; 20 U32 const hBitsL = cParams->hashLog; 21 U32 const mls = cParams->searchLength; 22 U32* const hashSmall = ms->chainTable; 23 U32 const hBitsS = cParams->chainLog; 24 const BYTE* const base = ms->window.base; 25 const BYTE* ip = base + ms->nextToUpdate; 26 const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE; 27 const U32 fastHashFillStep = 3; 28 29 /* Always insert every fastHashFillStep position into the hash tables. 30 * Insert the other positions into the large hash table if their entry 31 * is empty. 32 */ 33 for (; ip + fastHashFillStep - 1 <= iend; ip += fastHashFillStep) { 34 U32 const current = (U32)(ip - base); 35 U32 i; 36 for (i = 0; i < fastHashFillStep; ++i) { 37 size_t const smHash = ZSTD_hashPtr(ip + i, hBitsS, mls); 38 size_t const lgHash = ZSTD_hashPtr(ip + i, hBitsL, 8); 39 if (i == 0) 40 hashSmall[smHash] = current + i; 41 if (i == 0 || hashLarge[lgHash] == 0) 42 hashLarge[lgHash] = current + i; 43 } 44 } 45 } 46 47 48 FORCE_INLINE_TEMPLATE 49 size_t ZSTD_compressBlock_doubleFast_generic( 50 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 51 ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize, 52 U32 const mls /* template */) 53 { 54 U32* const hashLong = ms->hashTable; 55 const U32 hBitsL = cParams->hashLog; 56 U32* const hashSmall = ms->chainTable; 57 const U32 hBitsS = cParams->chainLog; 58 const BYTE* const base = ms->window.base; 59 const BYTE* const istart = (const BYTE*)src; 60 const BYTE* ip = istart; 61 const BYTE* anchor = istart; 62 const U32 lowestIndex = ms->window.dictLimit; 63 const BYTE* const lowest = base + lowestIndex; 64 const BYTE* const iend = istart + srcSize; 65 const BYTE* const ilimit = iend - HASH_READ_SIZE; 66 U32 offset_1=rep[0], offset_2=rep[1]; 67 U32 offsetSaved = 0; 68 69 /* init */ 70 ip += (ip==lowest); 71 { U32 const maxRep = (U32)(ip-lowest); 72 if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0; 73 if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0; 74 } 75 76 /* Main Search Loop */ 77 while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */ 78 size_t mLength; 79 size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8); 80 size_t const h = ZSTD_hashPtr(ip, hBitsS, mls); 81 U32 const current = (U32)(ip-base); 82 U32 const matchIndexL = hashLong[h2]; 83 U32 const matchIndexS = hashSmall[h]; 84 const BYTE* matchLong = base + matchIndexL; 85 const BYTE* match = base + matchIndexS; 86 hashLong[h2] = hashSmall[h] = current; /* update hash tables */ 87 88 assert(offset_1 <= current); /* supposed guaranteed by construction */ 89 if ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) { 90 /* favor repcode */ 91 mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4; 92 ip++; 93 ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH); 94 } else { 95 U32 offset; 96 if ( (matchIndexL > lowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip)) ) { 97 mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8; 98 offset = (U32)(ip-matchLong); 99 while (((ip>anchor) & (matchLong>lowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */ 100 } else if ( (matchIndexS > lowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) { 101 size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8); 102 U32 const matchIndexL3 = hashLong[hl3]; 103 const BYTE* matchL3 = base + matchIndexL3; 104 hashLong[hl3] = current + 1; 105 if ( (matchIndexL3 > lowestIndex) && (MEM_read64(matchL3) == MEM_read64(ip+1)) ) { 106 mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8; 107 ip++; 108 offset = (U32)(ip-matchL3); 109 while (((ip>anchor) & (matchL3>lowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */ 110 } else { 111 mLength = ZSTD_count(ip+4, match+4, iend) + 4; 112 offset = (U32)(ip-match); 113 while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ 114 } 115 } else { 116 ip += ((ip-anchor) >> kSearchStrength) + 1; 117 continue; 118 } 119 120 offset_2 = offset_1; 121 offset_1 = offset; 122 123 ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); 124 } 125 126 /* match found */ 127 ip += mLength; 128 anchor = ip; 129 130 if (ip <= ilimit) { 131 /* Fill Table */ 132 hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] = 133 hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2; /* here because current+2 could be > iend-8 */ 134 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = 135 hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base); 136 137 /* check immediate repcode */ 138 while ( (ip <= ilimit) 139 && ( (offset_2>0) 140 & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) { 141 /* store sequence */ 142 size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4; 143 { U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */ 144 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base); 145 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base); 146 ZSTD_storeSeq(seqStore, 0, anchor, 0, rLength-MINMATCH); 147 ip += rLength; 148 anchor = ip; 149 continue; /* faster when present ... (?) */ 150 } } } 151 152 /* save reps for next block */ 153 rep[0] = offset_1 ? offset_1 : offsetSaved; 154 rep[1] = offset_2 ? offset_2 : offsetSaved; 155 156 /* Return the last literals size */ 157 return iend - anchor; 158 } 159 160 161 size_t ZSTD_compressBlock_doubleFast( 162 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 163 ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize) 164 { 165 const U32 mls = cParams->searchLength; 166 switch(mls) 167 { 168 default: /* includes case 3 */ 169 case 4 : 170 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, cParams, src, srcSize, 4); 171 case 5 : 172 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, cParams, src, srcSize, 5); 173 case 6 : 174 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, cParams, src, srcSize, 6); 175 case 7 : 176 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, cParams, src, srcSize, 7); 177 } 178 } 179 180 181 static size_t ZSTD_compressBlock_doubleFast_extDict_generic( 182 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 183 ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize, 184 U32 const mls /* template */) 185 { 186 U32* const hashLong = ms->hashTable; 187 U32 const hBitsL = cParams->hashLog; 188 U32* const hashSmall = ms->chainTable; 189 U32 const hBitsS = cParams->chainLog; 190 const BYTE* const base = ms->window.base; 191 const BYTE* const dictBase = ms->window.dictBase; 192 const BYTE* const istart = (const BYTE*)src; 193 const BYTE* ip = istart; 194 const BYTE* anchor = istart; 195 const U32 lowestIndex = ms->window.lowLimit; 196 const BYTE* const dictStart = dictBase + lowestIndex; 197 const U32 dictLimit = ms->window.dictLimit; 198 const BYTE* const lowPrefixPtr = base + dictLimit; 199 const BYTE* const dictEnd = dictBase + dictLimit; 200 const BYTE* const iend = istart + srcSize; 201 const BYTE* const ilimit = iend - 8; 202 U32 offset_1=rep[0], offset_2=rep[1]; 203 204 /* Search Loop */ 205 while (ip < ilimit) { /* < instead of <=, because (ip+1) */ 206 const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls); 207 const U32 matchIndex = hashSmall[hSmall]; 208 const BYTE* matchBase = matchIndex < dictLimit ? dictBase : base; 209 const BYTE* match = matchBase + matchIndex; 210 211 const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8); 212 const U32 matchLongIndex = hashLong[hLong]; 213 const BYTE* matchLongBase = matchLongIndex < dictLimit ? dictBase : base; 214 const BYTE* matchLong = matchLongBase + matchLongIndex; 215 216 const U32 current = (U32)(ip-base); 217 const U32 repIndex = current + 1 - offset_1; /* offset_1 expected <= current +1 */ 218 const BYTE* repBase = repIndex < dictLimit ? dictBase : base; 219 const BYTE* repMatch = repBase + repIndex; 220 size_t mLength; 221 hashSmall[hSmall] = hashLong[hLong] = current; /* update hash table */ 222 223 if ( (((U32)((dictLimit-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex)) 224 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) { 225 const BYTE* repMatchEnd = repIndex < dictLimit ? dictEnd : iend; 226 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, lowPrefixPtr) + 4; 227 ip++; 228 ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH); 229 } else { 230 if ((matchLongIndex > lowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) { 231 const BYTE* matchEnd = matchLongIndex < dictLimit ? dictEnd : iend; 232 const BYTE* lowMatchPtr = matchLongIndex < dictLimit ? dictStart : lowPrefixPtr; 233 U32 offset; 234 mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, lowPrefixPtr) + 8; 235 offset = current - matchLongIndex; 236 while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */ 237 offset_2 = offset_1; 238 offset_1 = offset; 239 ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); 240 241 } else if ((matchIndex > lowestIndex) && (MEM_read32(match) == MEM_read32(ip))) { 242 size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8); 243 U32 const matchIndex3 = hashLong[h3]; 244 const BYTE* const match3Base = matchIndex3 < dictLimit ? dictBase : base; 245 const BYTE* match3 = match3Base + matchIndex3; 246 U32 offset; 247 hashLong[h3] = current + 1; 248 if ( (matchIndex3 > lowestIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) { 249 const BYTE* matchEnd = matchIndex3 < dictLimit ? dictEnd : iend; 250 const BYTE* lowMatchPtr = matchIndex3 < dictLimit ? dictStart : lowPrefixPtr; 251 mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, lowPrefixPtr) + 8; 252 ip++; 253 offset = current+1 - matchIndex3; 254 while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */ 255 } else { 256 const BYTE* matchEnd = matchIndex < dictLimit ? dictEnd : iend; 257 const BYTE* lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr; 258 mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, lowPrefixPtr) + 4; 259 offset = current - matchIndex; 260 while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ 261 } 262 offset_2 = offset_1; 263 offset_1 = offset; 264 ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); 265 266 } else { 267 ip += ((ip-anchor) >> kSearchStrength) + 1; 268 continue; 269 } } 270 271 /* found a match : store it */ 272 ip += mLength; 273 anchor = ip; 274 275 if (ip <= ilimit) { 276 /* Fill Table */ 277 hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2; 278 hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] = current+2; 279 hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base); 280 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base); 281 /* check immediate repcode */ 282 while (ip <= ilimit) { 283 U32 const current2 = (U32)(ip-base); 284 U32 const repIndex2 = current2 - offset_2; 285 const BYTE* repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2; 286 if ( (((U32)((dictLimit-1) - repIndex2) >= 3) & (repIndex2 > lowestIndex)) /* intentional overflow */ 287 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) { 288 const BYTE* const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend; 289 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, lowPrefixPtr) + 4; 290 U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */ 291 ZSTD_storeSeq(seqStore, 0, anchor, 0, repLength2-MINMATCH); 292 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2; 293 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2; 294 ip += repLength2; 295 anchor = ip; 296 continue; 297 } 298 break; 299 } } } 300 301 /* save reps for next block */ 302 rep[0] = offset_1; 303 rep[1] = offset_2; 304 305 /* Return the last literals size */ 306 return iend - anchor; 307 } 308 309 310 size_t ZSTD_compressBlock_doubleFast_extDict( 311 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 312 ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize) 313 { 314 U32 const mls = cParams->searchLength; 315 switch(mls) 316 { 317 default: /* includes case 3 */ 318 case 4 : 319 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, cParams, src, srcSize, 4); 320 case 5 : 321 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, cParams, src, srcSize, 5); 322 case 6 : 323 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, cParams, src, srcSize, 6); 324 case 7 : 325 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, cParams, src, srcSize, 7); 326 } 327 } 328