1 /* 2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "libadt/dict.hpp" 27 28 // Dictionaries - An Abstract Data Type 29 30 // %%%%% includes not needed with AVM framework - Ungar 31 32 #include <assert.h> 33 34 //------------------------------data----------------------------------------- 35 // String hash tables 36 #define MAXID 20 37 static uint8_t initflag = 0; // True after 1st initialization 38 static const char shft[MAXID] = {1,2,3,4,5,6,7,1,2,3,4,5,6,7,1,2,3,4,5,6}; 39 static short xsum[MAXID]; 40 41 //------------------------------bucket--------------------------------------- 42 class bucket : public ResourceObj { 43 public: 44 uint _cnt, _max; // Size of bucket 45 void **_keyvals; // Array of keys and values 46 }; 47 48 //------------------------------Dict----------------------------------------- 49 // The dictionary is kept has a hash table. The hash table is a even power 50 // of two, for nice modulo operations. Each bucket in the hash table points 51 // to a linear list of key-value pairs; each key & value is just a (void *). 52 // The list starts with a count. A hash lookup finds the list head, then a 53 // simple linear scan finds the key. If the table gets too full, it's 54 // doubled in size; the total amount of EXTRA times all hash functions are 55 // computed for the doubling is no more than the current size - thus the 56 // doubling in size costs no more than a constant factor in speed. 57 Dict::Dict(CmpKey initcmp, Hash inithash) : _arena(Thread::current()->resource_area()), 58 _hash(inithash), _cmp(initcmp) { 59 int i; 60 61 // Precompute table of null character hashes 62 if( !initflag ) { // Not initializated yet? 63 xsum[0] = (1<<shft[0])+1; // Initialize 64 for(i=1; i<MAXID; i++) { 65 xsum[i] = (1<<shft[i])+1+xsum[i-1]; 66 } 67 initflag = 1; // Never again 68 } 69 70 _size = 16; // Size is a power of 2 71 _cnt = 0; // Dictionary is empty 72 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size); 73 memset((void*)_bin,0,sizeof(bucket)*_size); 74 } 75 76 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena, int size) 77 : _arena(arena), _hash(inithash), _cmp(initcmp) { 78 int i; 79 80 // Precompute table of null character hashes 81 if( !initflag ) { // Not initializated yet? 82 xsum[0] = (1<<shft[0])+1; // Initialize 83 for(i=1; i<MAXID; i++) { 84 xsum[i] = (1<<shft[i])+1+xsum[i-1]; 85 } 86 initflag = 1; // Never again 87 } 88 89 i=16; 90 while( i < size ) i <<= 1; 91 _size = i; // Size is a power of 2 92 _cnt = 0; // Dictionary is empty 93 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size); 94 memset((void*)_bin,0,sizeof(bucket)*_size); 95 } 96 97 //------------------------------~Dict------------------------------------------ 98 // Delete an existing dictionary. 99 Dict::~Dict() { 100 /* 101 tty->print("~Dict %d/%d: ",_cnt,_size); 102 for( uint i=0; i < _size; i++) // For complete new table do 103 tty->print("%d ",_bin[i]._cnt); 104 tty->print("\n");*/ 105 /*for( uint i=0; i<_size; i++ ) { 106 FREE_FAST( _bin[i]._keyvals ); 107 } */ 108 } 109 110 //------------------------------Clear---------------------------------------- 111 // Zap to empty; ready for re-use 112 void Dict::Clear() { 113 _cnt = 0; // Empty contents 114 for( uint i=0; i<_size; i++ ) 115 _bin[i]._cnt = 0; // Empty buckets, but leave allocated 116 // Leave _size & _bin alone, under the assumption that dictionary will 117 // grow to this size again. 118 } 119 120 //------------------------------doubhash--------------------------------------- 121 // Double hash table size. If can't do so, just suffer. If can, then run 122 // thru old hash table, moving things to new table. Note that since hash 123 // table doubled, exactly 1 new bit is exposed in the mask - so everything 124 // in the old table ends up on 1 of two lists in the new table; a hi and a 125 // lo list depending on the value of the bit. 126 void Dict::doubhash(void) { 127 uint oldsize = _size; 128 _size <<= 1; // Double in size 129 _bin = (bucket*)_arena->Arealloc(_bin, sizeof(bucket) * oldsize, sizeof(bucket) * _size); 130 memset((void*)(&_bin[oldsize]), 0, oldsize * sizeof(bucket)); 131 // Rehash things to spread into new table 132 for (uint i = 0; i < oldsize; i++) { // For complete OLD table do 133 bucket *b = &_bin[i]; // Handy shortcut for _bin[i] 134 if (!b->_keyvals) continue; // Skip empties fast 135 136 bucket *nb = &_bin[i+oldsize]; // New bucket shortcut 137 uint j = b->_max; // Trim new bucket to nearest power of 2 138 while (j > b->_cnt) { j >>= 1; } // above old bucket _cnt 139 if (!j) { j = 1; } // Handle zero-sized buckets 140 nb->_max = j << 1; 141 // Allocate worst case space for key-value pairs 142 nb->_keyvals = (void**)_arena->Amalloc_4(sizeof(void *) * nb->_max * 2); 143 uint nbcnt = 0; 144 145 for (j = 0; j < b->_cnt; ) { // Rehash all keys in this bucket 146 void *key = b->_keyvals[j + j]; 147 if ((_hash(key) & (_size-1)) != i) { // Moving to hi bucket? 148 nb->_keyvals[nbcnt + nbcnt] = key; 149 nb->_keyvals[nbcnt + nbcnt + 1] = b->_keyvals[j + j + 1]; 150 nb->_cnt = nbcnt = nbcnt + 1; 151 b->_cnt--; // Remove key/value from lo bucket 152 b->_keyvals[j + j] = b->_keyvals[b->_cnt + b->_cnt]; 153 b->_keyvals[j + j + 1] = b->_keyvals[b->_cnt + b->_cnt + 1]; 154 // Don't increment j, hash compacted element also. 155 } else { 156 j++; // Iterate. 157 } 158 } // End of for all key-value pairs in bucket 159 } // End of for all buckets 160 } 161 162 //------------------------------Dict----------------------------------------- 163 // Deep copy a dictionary. 164 Dict::Dict( const Dict &d ) : _arena(d._arena), _size(d._size), _cnt(d._cnt), _hash(d._hash), _cmp(d._cmp) { 165 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size); 166 memcpy( (void*)_bin, (void*)d._bin, sizeof(bucket)*_size ); 167 for( uint i=0; i<_size; i++ ) { 168 if( !_bin[i]._keyvals ) continue; 169 _bin[i]._keyvals=(void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2); 170 memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*)); 171 } 172 } 173 174 //------------------------------Dict----------------------------------------- 175 // Deep copy a dictionary. 176 Dict &Dict::operator =( const Dict &d ) { 177 if( _size < d._size ) { // If must have more buckets 178 _arena = d._arena; 179 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size ); 180 memset( (void*)(&_bin[_size]), 0, (d._size-_size)*sizeof(bucket) ); 181 _size = d._size; 182 } 183 uint i; 184 for( i=0; i<_size; i++ ) // All buckets are empty 185 _bin[i]._cnt = 0; // But leave bucket allocations alone 186 _cnt = d._cnt; 187 *(Hash*)(&_hash) = d._hash; 188 *(CmpKey*)(&_cmp) = d._cmp; 189 for( i=0; i<_size; i++ ) { 190 bucket *b = &d._bin[i]; // Shortcut to source bucket 191 for( uint j=0; j<b->_cnt; j++ ) 192 Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] ); 193 } 194 return *this; 195 } 196 197 //------------------------------Insert---------------------------------------- 198 // Insert or replace a key/value pair in the given dictionary. If the 199 // dictionary is too full, it's size is doubled. The prior value being 200 // replaced is returned (NULL if this is a 1st insertion of that key). If 201 // an old value is found, it's swapped with the prior key-value pair on the 202 // list. This moves a commonly searched-for value towards the list head. 203 void *Dict::Insert(void *key, void *val, bool replace) { 204 uint hash = _hash( key ); // Get hash key 205 uint i = hash & (_size-1); // Get hash key, corrected for size 206 bucket *b = &_bin[i]; // Handy shortcut 207 for( uint j=0; j<b->_cnt; j++ ) { 208 if( !_cmp(key,b->_keyvals[j+j]) ) { 209 if (!replace) { 210 return b->_keyvals[j+j+1]; 211 } else { 212 void *prior = b->_keyvals[j+j+1]; 213 b->_keyvals[j+j ] = key; // Insert current key-value 214 b->_keyvals[j+j+1] = val; 215 return prior; // Return prior 216 } 217 } 218 } 219 if( ++_cnt > _size ) { // Hash table is full 220 doubhash(); // Grow whole table if too full 221 i = hash & (_size-1); // Rehash 222 b = &_bin[i]; // Handy shortcut 223 } 224 if( b->_cnt == b->_max ) { // Must grow bucket? 225 if( !b->_keyvals ) { 226 b->_max = 2; // Initial bucket size 227 b->_keyvals = (void**)_arena->Amalloc_4(sizeof(void*) * b->_max * 2); 228 } else { 229 b->_keyvals = (void**)_arena->Arealloc(b->_keyvals, sizeof(void*) * b->_max * 2, sizeof(void*) * b->_max * 4); 230 b->_max <<= 1; // Double bucket 231 } 232 } 233 b->_keyvals[b->_cnt+b->_cnt ] = key; 234 b->_keyvals[b->_cnt+b->_cnt+1] = val; 235 b->_cnt++; 236 return NULL; // Nothing found prior 237 } 238 239 //------------------------------Delete--------------------------------------- 240 // Find & remove a value from dictionary. Return old value. 241 void *Dict::Delete(void *key) { 242 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size 243 bucket *b = &_bin[i]; // Handy shortcut 244 for( uint j=0; j<b->_cnt; j++ ) 245 if( !_cmp(key,b->_keyvals[j+j]) ) { 246 void *prior = b->_keyvals[j+j+1]; 247 b->_cnt--; // Remove key/value from lo bucket 248 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ]; 249 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1]; 250 _cnt--; // One less thing in table 251 return prior; 252 } 253 return NULL; 254 } 255 256 //------------------------------FindDict------------------------------------- 257 // Find a key-value pair in the given dictionary. If not found, return NULL. 258 // If found, move key-value pair towards head of list. 259 void *Dict::operator [](const void *key) const { 260 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size 261 bucket *b = &_bin[i]; // Handy shortcut 262 for( uint j=0; j<b->_cnt; j++ ) 263 if( !_cmp(key,b->_keyvals[j+j]) ) 264 return b->_keyvals[j+j+1]; 265 return NULL; 266 } 267 268 //------------------------------CmpDict-------------------------------------- 269 // CmpDict compares two dictionaries; they must have the same keys (their 270 // keys must match using CmpKey) and they must have the same values (pointer 271 // comparison). If so 1 is returned, if not 0 is returned. 272 int32_t Dict::operator ==(const Dict &d2) const { 273 if( _cnt != d2._cnt ) return 0; 274 if( _hash != d2._hash ) return 0; 275 if( _cmp != d2._cmp ) return 0; 276 for( uint i=0; i < _size; i++) { // For complete hash table do 277 bucket *b = &_bin[i]; // Handy shortcut 278 if( b->_cnt != d2._bin[i]._cnt ) return 0; 279 if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) ) 280 return 0; // Key-value pairs must match 281 } 282 return 1; // All match, is OK 283 } 284 285 //------------------------------print------------------------------------------ 286 // Handier print routine 287 void Dict::print() { 288 DictI i(this); // Moved definition in iterator here because of g++. 289 tty->print("Dict@" INTPTR_FORMAT "[%d] = {", p2i(this), _cnt); 290 for( ; i.test(); ++i ) { 291 tty->print("(" INTPTR_FORMAT "," INTPTR_FORMAT "),", p2i(i._key), p2i(i._value)); 292 } 293 tty->print_cr("}"); 294 } 295 296 //------------------------------Hashing Functions---------------------------- 297 // Convert string to hash key. This algorithm implements a universal hash 298 // function with the multipliers frozen (ok, so it's not universal). The 299 // multipliers (and allowable characters) are all odd, so the resultant sum 300 // is odd - guaranteed not divisible by any power of two, so the hash tables 301 // can be any power of two with good results. Also, I choose multipliers 302 // that have only 2 bits set (the low is always set to be odd) so 303 // multiplication requires only shifts and adds. Characters are required to 304 // be in the range 0-127 (I double & add 1 to force oddness). Keys are 305 // limited to MAXID characters in length. Experimental evidence on 150K of 306 // C text shows excellent spreading of values for any size hash table. 307 int hashstr(const void *t) { 308 char c, k = 0; 309 int32_t sum = 0; 310 const char *s = (const char *)t; 311 312 while( ((c = *s++) != '\0') && (k < MAXID-1) ) { // Get characters till null or MAXID-1 313 c = (c<<1)+1; // Characters are always odd! 314 sum += c + (c<<shft[k++]); // Universal hash function 315 } 316 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size 317 } 318 319 //------------------------------hashptr-------------------------------------- 320 // Slimey cheap hash function; no guaranteed performance. Better than the 321 // default for pointers, especially on MS-DOS machines. 322 int hashptr(const void *key) { 323 return ((intptr_t)key >> 2); 324 } 325 326 // Slimey cheap hash function; no guaranteed performance. 327 int hashkey(const void *key) { 328 return (intptr_t)key; 329 } 330 331 //------------------------------Key Comparator Functions--------------------- 332 int32_t cmpstr(const void *k1, const void *k2) { 333 return strcmp((const char *)k1,(const char *)k2); 334 } 335 336 // Cheap key comparator. 337 int32_t cmpkey(const void *key1, const void *key2) { 338 if (key1 == key2) return 0; 339 intptr_t delta = (intptr_t)key1 - (intptr_t)key2; 340 if (delta > 0) return 1; 341 return -1; 342 } 343 344 //============================================================================= 345 //------------------------------reset------------------------------------------ 346 // Create an iterator and initialize the first variables. 347 void DictI::reset( const Dict *dict ) { 348 _d = dict; // The dictionary 349 _i = (uint)-1; // Before the first bin 350 _j = 0; // Nothing left in the current bin 351 ++(*this); // Step to first real value 352 } 353 354 //------------------------------next------------------------------------------- 355 // Find the next key-value pair in the dictionary, or return a NULL key and 356 // value. 357 void DictI::operator ++(void) { 358 if( _j-- ) { // Still working in current bin? 359 _key = _d->_bin[_i]._keyvals[_j+_j]; 360 _value = _d->_bin[_i]._keyvals[_j+_j+1]; 361 return; 362 } 363 364 while( ++_i < _d->_size ) { // Else scan for non-zero bucket 365 _j = _d->_bin[_i]._cnt; 366 if( !_j ) continue; 367 _j--; 368 _key = _d->_bin[_i]._keyvals[_j+_j]; 369 _value = _d->_bin[_i]._keyvals[_j+_j+1]; 370 return; 371 } 372 _key = _value = NULL; 373 }