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 }