1 /*
2 * Copyright (c) 1997, 2014, 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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
42
43 // The iostream is not needed and it gets confused for gcc by the
44 // define of bool.
45 //
46 // #include <iostream.h>
47
48 //------------------------------data-----------------------------------------
49 // String hash tables
50 #define MAXID 20
51 static byte initflag = 0; // True after 1st initialization
52 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};
53 static short xsum[MAXID];
54
55 //------------------------------bucket---------------------------------------
56 class bucket : public ResourceObj {
57 public:
58 uint _cnt, _max; // Size of bucket
59 void **_keyvals; // Array of keys and values
60 };
61
62 //------------------------------Dict-----------------------------------------
63 // The dictionary is kept has a hash table. The hash table is a even power
64 // of two, for nice modulo operations. Each bucket in the hash table points
65 // to a linear list of key-value pairs; each key & value is just a (void *).
66 // The list starts with a count. A hash lookup finds the list head, then a
67 // simple linear scan finds the key. If the table gets too full, it's
68 // doubled in size; the total amount of EXTRA times all hash functions are
69 // computed for the doubling is no more than the current size - thus the
70 // doubling in size costs no more than a constant factor in speed.
71 Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp),
72 _arena(Thread::current()->resource_area()) {
73 int i;
74
75 // Precompute table of null character hashes
76 if( !initflag ) { // Not initializated yet?
77 xsum[0] = (1<<shft[0])+1; // Initialize
78 for(i=1; i<MAXID; i++) {
79 xsum[i] = (1<<shft[i])+1+xsum[i-1];
80 }
81 initflag = 1; // Never again
82 }
83
84 _size = 16; // Size is a power of 2
85 _cnt = 0; // Dictionary is empty
86 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
87 memset(_bin,0,sizeof(bucket)*_size);
88 }
89
90 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena, int size)
91 : _hash(inithash), _cmp(initcmp), _arena(arena) {
92 int i;
93
94 // Precompute table of null character hashes
95 if( !initflag ) { // Not initializated yet?
96 xsum[0] = (1<<shft[0])+1; // Initialize
97 for(i=1; i<MAXID; i++) {
98 xsum[i] = (1<<shft[i])+1+xsum[i-1];
99 }
100 initflag = 1; // Never again
101 }
102
103 i=16;
104 while( i < size ) i <<= 1;
105 _size = i; // Size is a power of 2
106 _cnt = 0; // Dictionary is empty
107 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
108 memset(_bin,0,sizeof(bucket)*_size);
109 }
110
111 //------------------------------~Dict------------------------------------------
112 // Delete an existing dictionary.
113 Dict::~Dict() {
114 /*
115 tty->print("~Dict %d/%d: ",_cnt,_size);
116 for( uint i=0; i < _size; i++) // For complete new table do
117 tty->print("%d ",_bin[i]._cnt);
118 tty->print("\n");*/
119 /*for( uint i=0; i<_size; i++ ) {
120 FREE_FAST( _bin[i]._keyvals );
121 } */
122 }
123
124 //------------------------------Clear----------------------------------------
125 // Zap to empty; ready for re-use
126 void Dict::Clear() {
127 _cnt = 0; // Empty contents
128 for( uint i=0; i<_size; i++ )
129 _bin[i]._cnt = 0; // Empty buckets, but leave allocated
130 // Leave _size & _bin alone, under the assumption that dictionary will
131 // grow to this size again.
132 }
133
134 //------------------------------doubhash---------------------------------------
135 // Double hash table size. If can't do so, just suffer. If can, then run
136 // thru old hash table, moving things to new table. Note that since hash
137 // table doubled, exactly 1 new bit is exposed in the mask - so everything
138 // in the old table ends up on 1 of two lists in the new table; a hi and a
139 // lo list depending on the value of the bit.
140 void Dict::doubhash(void) {
141 uint oldsize = _size;
142 _size <<= 1; // Double in size
143 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );
144 memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );
145 // Rehash things to spread into new table
146 for( uint i=0; i < oldsize; i++) { // For complete OLD table do
147 bucket *b = &_bin[i]; // Handy shortcut for _bin[i]
148 if( !b->_keyvals ) continue; // Skip empties fast
149
150 bucket *nb = &_bin[i+oldsize]; // New bucket shortcut
151 uint j = b->_max; // Trim new bucket to nearest power of 2
152 while( j > b->_cnt ) j >>= 1; // above old bucket _cnt
153 if( !j ) j = 1; // Handle zero-sized buckets
154 nb->_max = j<<1;
155 // Allocate worst case space for key-value pairs
156 nb->_keyvals = (void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );
157 uint nbcnt = 0;
158
159 for( j=0; j<b->_cnt; j++ ) { // Rehash all keys in this bucket
160 void *key = b->_keyvals[j+j];
161 if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?
162 nb->_keyvals[nbcnt+nbcnt] = key;
163 nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];
164 nb->_cnt = nbcnt = nbcnt+1;
165 b->_cnt--; // Remove key/value from lo bucket
166 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
167 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
168 j--; // Hash compacted element also
169 }
170 } // End of for all key-value pairs in bucket
171 } // End of for all buckets
172
173
174 }
175
176 //------------------------------Dict-----------------------------------------
177 // Deep copy a dictionary.
178 Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {
179 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
180 memcpy( _bin, d._bin, sizeof(bucket)*_size );
181 for( uint i=0; i<_size; i++ ) {
182 if( !_bin[i]._keyvals ) continue;
183 _bin[i]._keyvals=(void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2);
184 memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));
185 }
186 }
187
188 //------------------------------Dict-----------------------------------------
189 // Deep copy a dictionary.
190 Dict &Dict::operator =( const Dict &d ) {
191 if( _size < d._size ) { // If must have more buckets
192 _arena = d._arena;
193 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );
194 memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
195 _size = d._size;
196 }
197 uint i;
198 for( i=0; i<_size; i++ ) // All buckets are empty
199 _bin[i]._cnt = 0; // But leave bucket allocations alone
200 _cnt = d._cnt;
201 *(Hash*)(&_hash) = d._hash;
202 *(CmpKey*)(&_cmp) = d._cmp;
203 for( i=0; i<_size; i++ ) {
204 bucket *b = &d._bin[i]; // Shortcut to source bucket
205 for( uint j=0; j<b->_cnt; j++ )
206 Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );
207 }
208 return *this;
209 }
210
211 //------------------------------Insert----------------------------------------
212 // Insert or replace a key/value pair in the given dictionary. If the
213 // dictionary is too full, it's size is doubled. The prior value being
214 // replaced is returned (NULL if this is a 1st insertion of that key). If
215 // an old value is found, it's swapped with the prior key-value pair on the
216 // list. This moves a commonly searched-for value towards the list head.
217 void *Dict::Insert(void *key, void *val, bool replace) {
218 uint hash = _hash( key ); // Get hash key
219 uint i = hash & (_size-1); // Get hash key, corrected for size
220 bucket *b = &_bin[i]; // Handy shortcut
221 for( uint j=0; j<b->_cnt; j++ ) {
222 if( !_cmp(key,b->_keyvals[j+j]) ) {
223 if (!replace) {
224 return b->_keyvals[j+j+1];
225 } else {
226 void *prior = b->_keyvals[j+j+1];
227 b->_keyvals[j+j ] = key; // Insert current key-value
228 b->_keyvals[j+j+1] = val;
229 return prior; // Return prior
230 }
231 }
232 }
233 if( ++_cnt > _size ) { // Hash table is full
234 doubhash(); // Grow whole table if too full
235 i = hash & (_size-1); // Rehash
236 b = &_bin[i]; // Handy shortcut
237 }
238 if( b->_cnt == b->_max ) { // Must grow bucket?
239 if( !b->_keyvals ) {
240 b->_max = 2; // Initial bucket size
241 b->_keyvals = (void**)_arena->Amalloc_4(sizeof(void*) * b->_max * 2);
242 } else {
243 b->_keyvals = (void**)_arena->Arealloc(b->_keyvals, sizeof(void*) * b->_max * 2, sizeof(void*) * b->_max * 4);
244 b->_max <<= 1; // Double bucket
245 }
246 }
247 b->_keyvals[b->_cnt+b->_cnt ] = key;
248 b->_keyvals[b->_cnt+b->_cnt+1] = val;
249 b->_cnt++;
250 return NULL; // Nothing found prior
251 }
252
253 //------------------------------Delete---------------------------------------
254 // Find & remove a value from dictionary. Return old value.
255 void *Dict::Delete(void *key) {
256 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size
257 bucket *b = &_bin[i]; // Handy shortcut
258 for( uint j=0; j<b->_cnt; j++ )
259 if( !_cmp(key,b->_keyvals[j+j]) ) {
260 void *prior = b->_keyvals[j+j+1];
261 b->_cnt--; // Remove key/value from lo bucket
262 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
263 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
264 _cnt--; // One less thing in table
265 return prior;
266 }
267 return NULL;
268 }
269
270 //------------------------------FindDict-------------------------------------
271 // Find a key-value pair in the given dictionary. If not found, return NULL.
272 // If found, move key-value pair towards head of list.
273 void *Dict::operator [](const void *key) const {
274 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size
275 bucket *b = &_bin[i]; // Handy shortcut
276 for( uint j=0; j<b->_cnt; j++ )
277 if( !_cmp(key,b->_keyvals[j+j]) )
278 return b->_keyvals[j+j+1];
279 return NULL;
280 }
281
282 //------------------------------CmpDict--------------------------------------
283 // CmpDict compares two dictionaries; they must have the same keys (their
284 // keys must match using CmpKey) and they must have the same values (pointer
285 // comparison). If so 1 is returned, if not 0 is returned.
286 int32 Dict::operator ==(const Dict &d2) const {
287 if( _cnt != d2._cnt ) return 0;
288 if( _hash != d2._hash ) return 0;
289 if( _cmp != d2._cmp ) return 0;
290 for( uint i=0; i < _size; i++) { // For complete hash table do
291 bucket *b = &_bin[i]; // Handy shortcut
292 if( b->_cnt != d2._bin[i]._cnt ) return 0;
293 if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )
294 return 0; // Key-value pairs must match
295 }
296 return 1; // All match, is OK
297 }
298
299 //------------------------------print------------------------------------------
300 // Handier print routine
301 void Dict::print() {
302 DictI i(this); // Moved definition in iterator here because of g++.
303 tty->print("Dict@0x%lx[%d] = {", this, _cnt);
304 for( ; i.test(); ++i ) {
305 tty->print("(0x%lx,0x%lx),", i._key, i._value);
306 }
307 tty->print_cr("}");
308 }
309
310 //------------------------------Hashing Functions----------------------------
311 // Convert string to hash key. This algorithm implements a universal hash
312 // function with the multipliers frozen (ok, so it's not universal). The
313 // multipliers (and allowable characters) are all odd, so the resultant sum
314 // is odd - guaranteed not divisible by any power of two, so the hash tables
315 // can be any power of two with good results. Also, I choose multipliers
316 // that have only 2 bits set (the low is always set to be odd) so
317 // multiplication requires only shifts and adds. Characters are required to
318 // be in the range 0-127 (I double & add 1 to force oddness). Keys are
319 // limited to MAXID characters in length. Experimental evidence on 150K of
320 // C text shows excellent spreading of values for any size hash table.
321 int hashstr(const void *t) {
322 register char c, k = 0;
323 register int32 sum = 0;
324 register const char *s = (const char *)t;
325
326 while( ((c = *s++) != '\0') && (k < MAXID-1) ) { // Get characters till null or MAXID-1
327 c = (c<<1)+1; // Characters are always odd!
328 sum += c + (c<<shft[k++]); // Universal hash function
329 }
330 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size
331 }
332
333 //------------------------------hashptr--------------------------------------
334 // Slimey cheap hash function; no guaranteed performance. Better than the
335 // default for pointers, especially on MS-DOS machines.
336 int hashptr(const void *key) {
337 #ifdef __TURBOC__
338 return ((intptr_t)key >> 16);
339 #else // __TURBOC__
340 return ((intptr_t)key >> 2);
341 #endif
342 }
343
344 // Slimey cheap hash function; no guaranteed performance.
345 int hashkey(const void *key) {
346 return (intptr_t)key;
347 }
348
349 //------------------------------Key Comparator Functions---------------------
350 int32 cmpstr(const void *k1, const void *k2) {
351 return strcmp((const char *)k1,(const char *)k2);
352 }
353
354 // Cheap key comparator.
355 int32 cmpkey(const void *key1, const void *key2) {
356 if (key1 == key2) return 0;
357 intptr_t delta = (intptr_t)key1 - (intptr_t)key2;
358 if (delta > 0) return 1;
359 return -1;
360 }
361
362 //=============================================================================
363 //------------------------------reset------------------------------------------
364 // Create an iterator and initialize the first variables.
365 void DictI::reset( const Dict *dict ) {
366 _d = dict; // The dictionary
367 _i = (uint)-1; // Before the first bin
368 _j = 0; // Nothing left in the current bin
369 ++(*this); // Step to first real value
370 }
371
372 //------------------------------next-------------------------------------------
373 // Find the next key-value pair in the dictionary, or return a NULL key and
374 // value.
375 void DictI::operator ++(void) {
376 if( _j-- ) { // Still working in current bin?
377 _key = _d->_bin[_i]._keyvals[_j+_j];
378 _value = _d->_bin[_i]._keyvals[_j+_j+1];
379 return;
380 }
381
382 while( ++_i < _d->_size ) { // Else scan for non-zero bucket
383 _j = _d->_bin[_i]._cnt;
384 if( !_j ) continue;
385 _j--;
386 _key = _d->_bin[_i]._keyvals[_j+_j];
387 _value = _d->_bin[_i]._keyvals[_j+_j+1];
388 return;
389 }
390 _key = _value = NULL;
391 }