1 /*
2 * Copyright (c) 1997, 2010, 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 #include "memory/allocation.inline.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "runtime/thread.hpp"
30
31 // Dictionaries - An Abstract Data Type
32
33 // %%%%% includes not needed with AVM framework - Ungar
34
35 // #include "port.hpp"
36 //IMPLEMENTATION
37 // #include "dict.hpp"
38
39 #include <assert.h>
40
41 // The iostream is not needed and it gets confused for gcc by the
42 // define of bool.
43 //
44 // #include <iostream.h>
45
46 //------------------------------data-----------------------------------------
47 // String hash tables
48 #define MAXID 20
49 static byte initflag = 0; // True after 1st initialization
50 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};
51 static short xsum[MAXID];
52
53 //------------------------------bucket---------------------------------------
54 class bucket : public ResourceObj {
55 public:
56 uint _cnt, _max; // Size of bucket
57 void **_keyvals; // Array of keys and values
58 };
59
60 //------------------------------Dict-----------------------------------------
61 // The dictionary is kept has a hash table. The hash table is a even power
62 // of two, for nice modulo operations. Each bucket in the hash table points
63 // to a linear list of key-value pairs; each key & value is just a (void *).
64 // The list starts with a count. A hash lookup finds the list head, then a
65 // simple linear scan finds the key. If the table gets too full, it's
66 // doubled in size; the total amount of EXTRA times all hash functions are
67 // computed for the doubling is no more than the current size - thus the
68 // doubling in size costs no more than a constant factor in speed.
69 Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp),
70 _arena(Thread::current()->resource_area()) {
71 int i;
72
73 // Precompute table of null character hashes
74 if( !initflag ) { // Not initializated yet?
75 xsum[0] = (1<<shft[0])+1; // Initialize
76 for(i=1; i<MAXID; i++) {
77 xsum[i] = (1<<shft[i])+1+xsum[i-1];
78 }
79 initflag = 1; // Never again
80 }
81
82 _size = 16; // Size is a power of 2
83 _cnt = 0; // Dictionary is empty
84 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
85 memset(_bin,0,sizeof(bucket)*_size);
86 }
87
88 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena, int size)
89 : _hash(inithash), _cmp(initcmp), _arena(arena) {
90 int i;
91
92 // Precompute table of null character hashes
93 if( !initflag ) { // Not initializated yet?
94 xsum[0] = (1<<shft[0])+1; // Initialize
95 for(i=1; i<MAXID; i++) {
96 xsum[i] = (1<<shft[i])+1+xsum[i-1];
97 }
98 initflag = 1; // Never again
99 }
100
101 i=16;
102 while( i < size ) i <<= 1;
103 _size = i; // Size is a power of 2
104 _cnt = 0; // Dictionary is empty
105 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
106 memset(_bin,0,sizeof(bucket)*_size);
107 }
108
109 //------------------------------~Dict------------------------------------------
110 // Delete an existing dictionary.
111 Dict::~Dict() {
112 /*
113 tty->print("~Dict %d/%d: ",_cnt,_size);
114 for( uint i=0; i < _size; i++) // For complete new table do
115 tty->print("%d ",_bin[i]._cnt);
116 tty->print("\n");*/
117 /*for( uint i=0; i<_size; i++ ) {
118 FREE_FAST( _bin[i]._keyvals );
119 } */
120 }
121
122 //------------------------------Clear----------------------------------------
123 // Zap to empty; ready for re-use
124 void Dict::Clear() {
125 _cnt = 0; // Empty contents
126 for( uint i=0; i<_size; i++ )
127 _bin[i]._cnt = 0; // Empty buckets, but leave allocated
128 // Leave _size & _bin alone, under the assumption that dictionary will
129 // grow to this size again.
130 }
131
132 //------------------------------doubhash---------------------------------------
133 // Double hash table size. If can't do so, just suffer. If can, then run
134 // thru old hash table, moving things to new table. Note that since hash
135 // table doubled, exactly 1 new bit is exposed in the mask - so everything
136 // in the old table ends up on 1 of two lists in the new table; a hi and a
137 // lo list depending on the value of the bit.
138 void Dict::doubhash(void) {
139 uint oldsize = _size;
140 _size <<= 1; // Double in size
141 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );
142 memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );
143 // Rehash things to spread into new table
144 for( uint i=0; i < oldsize; i++) { // For complete OLD table do
145 bucket *b = &_bin[i]; // Handy shortcut for _bin[i]
146 if( !b->_keyvals ) continue; // Skip empties fast
147
148 bucket *nb = &_bin[i+oldsize]; // New bucket shortcut
149 uint j = b->_max; // Trim new bucket to nearest power of 2
150 while( j > b->_cnt ) j >>= 1; // above old bucket _cnt
151 if( !j ) j = 1; // Handle zero-sized buckets
152 nb->_max = j<<1;
153 // Allocate worst case space for key-value pairs
154 nb->_keyvals = (void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );
155 uint nbcnt = 0;
156
157 for( j=0; j<b->_cnt; j++ ) { // Rehash all keys in this bucket
158 void *key = b->_keyvals[j+j];
159 if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?
160 nb->_keyvals[nbcnt+nbcnt] = key;
161 nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];
162 nb->_cnt = nbcnt = nbcnt+1;
163 b->_cnt--; // Remove key/value from lo bucket
164 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
165 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
166 j--; // Hash compacted element also
167 }
168 } // End of for all key-value pairs in bucket
169 } // End of for all buckets
170
171
172 }
173
174 //------------------------------Dict-----------------------------------------
175 // Deep copy a dictionary.
176 Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {
177 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
178 memcpy( _bin, d._bin, sizeof(bucket)*_size );
179 for( uint i=0; i<_size; i++ ) {
180 if( !_bin[i]._keyvals ) continue;
181 _bin[i]._keyvals=(void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2);
182 memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));
183 }
184 }
185
186 //------------------------------Dict-----------------------------------------
187 // Deep copy a dictionary.
188 Dict &Dict::operator =( const Dict &d ) {
189 if( _size < d._size ) { // If must have more buckets
190 _arena = d._arena;
191 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );
192 memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
193 _size = d._size;
194 }
195 uint i;
196 for( i=0; i<_size; i++ ) // All buckets are empty
197 _bin[i]._cnt = 0; // But leave bucket allocations alone
198 _cnt = d._cnt;
199 *(Hash*)(&_hash) = d._hash;
200 *(CmpKey*)(&_cmp) = d._cmp;
201 for( i=0; i<_size; i++ ) {
202 bucket *b = &d._bin[i]; // Shortcut to source bucket
203 for( uint j=0; j<b->_cnt; j++ )
204 Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );
205 }
206 return *this;
207 }
208
209 //------------------------------Insert----------------------------------------
210 // Insert or replace a key/value pair in the given dictionary. If the
211 // dictionary is too full, it's size is doubled. The prior value being
212 // replaced is returned (NULL if this is a 1st insertion of that key). If
213 // an old value is found, it's swapped with the prior key-value pair on the
214 // list. This moves a commonly searched-for value towards the list head.
215 void *Dict::Insert(void *key, void *val, bool replace) {
216 uint hash = _hash( key ); // Get hash key
217 uint i = hash & (_size-1); // Get hash key, corrected for size
218 bucket *b = &_bin[i]; // Handy shortcut
219 for( uint j=0; j<b->_cnt; j++ ) {
220 if( !_cmp(key,b->_keyvals[j+j]) ) {
221 if (!replace) {
222 return b->_keyvals[j+j+1];
223 } else {
224 void *prior = b->_keyvals[j+j+1];
225 b->_keyvals[j+j ] = key; // Insert current key-value
226 b->_keyvals[j+j+1] = val;
227 return prior; // Return prior
228 }
229 }
230 }
231 if( ++_cnt > _size ) { // Hash table is full
232 doubhash(); // Grow whole table if too full
233 i = hash & (_size-1); // Rehash
234 b = &_bin[i]; // Handy shortcut
235 }
236 if( b->_cnt == b->_max ) { // Must grow bucket?
237 if( !b->_keyvals ) {
238 b->_max = 2; // Initial bucket size
239 b->_keyvals = (void**)_arena->Amalloc_4(sizeof(void*) * b->_max * 2);
240 } else {
241 b->_keyvals = (void**)_arena->Arealloc(b->_keyvals, sizeof(void*) * b->_max * 2, sizeof(void*) * b->_max * 4);
242 b->_max <<= 1; // Double bucket
243 }
244 }
245 b->_keyvals[b->_cnt+b->_cnt ] = key;
246 b->_keyvals[b->_cnt+b->_cnt+1] = val;
247 b->_cnt++;
248 return NULL; // Nothing found prior
249 }
250
251 //------------------------------Delete---------------------------------------
252 // Find & remove a value from dictionary. Return old value.
253 void *Dict::Delete(void *key) {
254 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size
255 bucket *b = &_bin[i]; // Handy shortcut
256 for( uint j=0; j<b->_cnt; j++ )
257 if( !_cmp(key,b->_keyvals[j+j]) ) {
258 void *prior = b->_keyvals[j+j+1];
259 b->_cnt--; // Remove key/value from lo bucket
260 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
261 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
262 _cnt--; // One less thing in table
263 return prior;
264 }
265 return NULL;
266 }
267
268 //------------------------------FindDict-------------------------------------
269 // Find a key-value pair in the given dictionary. If not found, return NULL.
270 // If found, move key-value pair towards head of list.
271 void *Dict::operator [](const void *key) const {
272 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size
273 bucket *b = &_bin[i]; // Handy shortcut
274 for( uint j=0; j<b->_cnt; j++ )
275 if( !_cmp(key,b->_keyvals[j+j]) )
276 return b->_keyvals[j+j+1];
277 return NULL;
278 }
279
280 //------------------------------CmpDict--------------------------------------
281 // CmpDict compares two dictionaries; they must have the same keys (their
282 // keys must match using CmpKey) and they must have the same values (pointer
283 // comparison). If so 1 is returned, if not 0 is returned.
284 int32 Dict::operator ==(const Dict &d2) const {
285 if( _cnt != d2._cnt ) return 0;
286 if( _hash != d2._hash ) return 0;
287 if( _cmp != d2._cmp ) return 0;
288 for( uint i=0; i < _size; i++) { // For complete hash table do
289 bucket *b = &_bin[i]; // Handy shortcut
290 if( b->_cnt != d2._bin[i]._cnt ) return 0;
291 if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )
292 return 0; // Key-value pairs must match
293 }
294 return 1; // All match, is OK
295 }
296
297 //------------------------------print------------------------------------------
298 // Handier print routine
299 void Dict::print() {
300 DictI i(this); // Moved definition in iterator here because of g++.
301 tty->print("Dict@0x%lx[%d] = {", this, _cnt);
302 for( ; i.test(); ++i ) {
303 tty->print("(0x%lx,0x%lx),", i._key, i._value);
304 }
305 tty->print_cr("}");
306 }
307
308 //------------------------------Hashing Functions----------------------------
309 // Convert string to hash key. This algorithm implements a universal hash
310 // function with the multipliers frozen (ok, so it's not universal). The
311 // multipliers (and allowable characters) are all odd, so the resultant sum
312 // is odd - guaranteed not divisible by any power of two, so the hash tables
313 // can be any power of two with good results. Also, I choose multipliers
314 // that have only 2 bits set (the low is always set to be odd) so
315 // multiplication requires only shifts and adds. Characters are required to
316 // be in the range 0-127 (I double & add 1 to force oddness). Keys are
317 // limited to MAXID characters in length. Experimental evidence on 150K of
318 // C text shows excellent spreading of values for any size hash table.
319 int hashstr(const void *t) {
320 register char c, k = 0;
321 register int32 sum = 0;
322 register const char *s = (const char *)t;
323
324 while( ((c = *s++) != '\0') && (k < MAXID-1) ) { // Get characters till null or MAXID-1
325 c = (c<<1)+1; // Characters are always odd!
326 sum += c + (c<<shft[k++]); // Universal hash function
327 }
328 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size
329 }
330
331 //------------------------------hashptr--------------------------------------
332 // Slimey cheap hash function; no guaranteed performance. Better than the
333 // default for pointers, especially on MS-DOS machines.
334 int hashptr(const void *key) {
335 #ifdef __TURBOC__
336 return ((intptr_t)key >> 16);
337 #else // __TURBOC__
338 return ((intptr_t)key >> 2);
339 #endif
340 }
341
342 // Slimey cheap hash function; no guaranteed performance.
343 int hashkey(const void *key) {
344 return (intptr_t)key;
345 }
346
347 //------------------------------Key Comparator Functions---------------------
348 int32 cmpstr(const void *k1, const void *k2) {
349 return strcmp((const char *)k1,(const char *)k2);
350 }
351
352 // Cheap key comparator.
353 int32 cmpkey(const void *key1, const void *key2) {
354 if (key1 == key2) return 0;
355 intptr_t delta = (intptr_t)key1 - (intptr_t)key2;
356 if (delta > 0) return 1;
357 return -1;
358 }
359
360 //=============================================================================
361 //------------------------------reset------------------------------------------
362 // Create an iterator and initialize the first variables.
363 void DictI::reset( const Dict *dict ) {
364 _d = dict; // The dictionary
365 _i = (uint)-1; // Before the first bin
366 _j = 0; // Nothing left in the current bin
367 ++(*this); // Step to first real value
368 }
369
370 //------------------------------next-------------------------------------------
371 // Find the next key-value pair in the dictionary, or return a NULL key and
372 // value.
373 void DictI::operator ++(void) {
374 if( _j-- ) { // Still working in current bin?
375 _key = _d->_bin[_i]._keyvals[_j+_j];
376 _value = _d->_bin[_i]._keyvals[_j+_j+1];
377 return;
378 }
379
380 while( ++_i < _d->_size ) { // Else scan for non-zero bucket
381 _j = _d->_bin[_i]._cnt;
382 if( !_j ) continue;
383 _j--;
384 _key = _d->_bin[_i]._keyvals[_j+_j];
385 _value = _d->_bin[_i]._keyvals[_j+_j+1];
386 return;
387 }
388 _key = _value = NULL;
389 }