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comparison src/share/vm/libadt/dict.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1997-2003 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // Dictionaries - An Abstract Data Type
26
27 #include "incls/_precompiled.incl"
28 #include "incls/_dict.cpp.incl"
29
30 // %%%%% includes not needed with AVM framework - Ungar
31
32 // #include "port.hpp"
33 //IMPLEMENTATION
34 // #include "dict.hpp"
35
36 #include <assert.h>
37
38 // The iostream is not needed and it gets confused for gcc by the
39 // define of bool.
40 //
41 // #include <iostream.h>
42
43 //------------------------------data-----------------------------------------
44 // String hash tables
45 #define MAXID 20
46 static byte initflag = 0; // True after 1st initialization
47 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};
48 static short xsum[MAXID];
49
50 //------------------------------bucket---------------------------------------
51 class bucket : public ResourceObj {
52 public:
53 uint _cnt, _max; // Size of bucket
54 void **_keyvals; // Array of keys and values
55 };
56
57 //------------------------------Dict-----------------------------------------
58 // The dictionary is kept has a hash table. The hash table is a even power
59 // of two, for nice modulo operations. Each bucket in the hash table points
60 // to a linear list of key-value pairs; each key & value is just a (void *).
61 // The list starts with a count. A hash lookup finds the list head, then a
62 // simple linear scan finds the key. If the table gets too full, it's
63 // doubled in size; the total amount of EXTRA times all hash functions are
64 // computed for the doubling is no more than the current size - thus the
65 // doubling in size costs no more than a constant factor in speed.
66 Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp),
67 _arena(Thread::current()->resource_area()) {
68 int i;
69
70 // Precompute table of null character hashes
71 if( !initflag ) { // Not initializated yet?
72 xsum[0] = (1<<shft[0])+1; // Initialize
73 for(i=1; i<MAXID; i++) {
74 xsum[i] = (1<<shft[i])+1+xsum[i-1];
75 }
76 initflag = 1; // Never again
77 }
78
79 _size = 16; // Size is a power of 2
80 _cnt = 0; // Dictionary is empty
81 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
82 memset(_bin,0,sizeof(bucket)*_size);
83 }
84
85 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena, int size)
86 : _hash(inithash), _cmp(initcmp), _arena(arena) {
87 int i;
88
89 // Precompute table of null character hashes
90 if( !initflag ) { // Not initializated yet?
91 xsum[0] = (1<<shft[0])+1; // Initialize
92 for(i=1; i<MAXID; i++) {
93 xsum[i] = (1<<shft[i])+1+xsum[i-1];
94 }
95 initflag = 1; // Never again
96 }
97
98 i=16;
99 while( i < size ) i <<= 1;
100 _size = i; // Size is a power of 2
101 _cnt = 0; // Dictionary is empty
102 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
103 memset(_bin,0,sizeof(bucket)*_size);
104 }
105
106 //------------------------------~Dict------------------------------------------
107 // Delete an existing dictionary.
108 Dict::~Dict() {
109 /*
110 tty->print("~Dict %d/%d: ",_cnt,_size);
111 for( uint i=0; i < _size; i++) // For complete new table do
112 tty->print("%d ",_bin[i]._cnt);
113 tty->print("\n");*/
114 /*for( uint i=0; i<_size; i++ ) {
115 FREE_FAST( _bin[i]._keyvals );
116 } */
117 }
118
119 //------------------------------Clear----------------------------------------
120 // Zap to empty; ready for re-use
121 void Dict::Clear() {
122 _cnt = 0; // Empty contents
123 for( uint i=0; i<_size; i++ )
124 _bin[i]._cnt = 0; // Empty buckets, but leave allocated
125 // Leave _size & _bin alone, under the assumption that dictionary will
126 // grow to this size again.
127 }
128
129 //------------------------------doubhash---------------------------------------
130 // Double hash table size. If can't do so, just suffer. If can, then run
131 // thru old hash table, moving things to new table. Note that since hash
132 // table doubled, exactly 1 new bit is exposed in the mask - so everything
133 // in the old table ends up on 1 of two lists in the new table; a hi and a
134 // lo list depending on the value of the bit.
135 void Dict::doubhash(void) {
136 uint oldsize = _size;
137 _size <<= 1; // Double in size
138 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );
139 memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );
140 // Rehash things to spread into new table
141 for( uint i=0; i < oldsize; i++) { // For complete OLD table do
142 bucket *b = &_bin[i]; // Handy shortcut for _bin[i]
143 if( !b->_keyvals ) continue; // Skip empties fast
144
145 bucket *nb = &_bin[i+oldsize]; // New bucket shortcut
146 uint j = b->_max; // Trim new bucket to nearest power of 2
147 while( j > b->_cnt ) j >>= 1; // above old bucket _cnt
148 if( !j ) j = 1; // Handle zero-sized buckets
149 nb->_max = j<<1;
150 // Allocate worst case space for key-value pairs
151 nb->_keyvals = (void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );
152 uint nbcnt = 0;
153
154 for( j=0; j<b->_cnt; j++ ) { // Rehash all keys in this bucket
155 void *key = b->_keyvals[j+j];
156 if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?
157 nb->_keyvals[nbcnt+nbcnt] = key;
158 nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];
159 nb->_cnt = nbcnt = nbcnt+1;
160 b->_cnt--; // Remove key/value from lo bucket
161 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
162 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
163 j--; // Hash compacted element also
164 }
165 } // End of for all key-value pairs in bucket
166 } // End of for all buckets
167
168
169 }
170
171 //------------------------------Dict-----------------------------------------
172 // Deep copy a dictionary.
173 Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {
174 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
175 memcpy( _bin, d._bin, sizeof(bucket)*_size );
176 for( uint i=0; i<_size; i++ ) {
177 if( !_bin[i]._keyvals ) continue;
178 _bin[i]._keyvals=(void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2);
179 memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));
180 }
181 }
182
183 //------------------------------Dict-----------------------------------------
184 // Deep copy a dictionary.
185 Dict &Dict::operator =( const Dict &d ) {
186 if( _size < d._size ) { // If must have more buckets
187 _arena = d._arena;
188 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );
189 memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
190 _size = d._size;
191 }
192 uint i;
193 for( i=0; i<_size; i++ ) // All buckets are empty
194 _bin[i]._cnt = 0; // But leave bucket allocations alone
195 _cnt = d._cnt;
196 *(Hash*)(&_hash) = d._hash;
197 *(CmpKey*)(&_cmp) = d._cmp;
198 for( i=0; i<_size; i++ ) {
199 bucket *b = &d._bin[i]; // Shortcut to source bucket
200 for( uint j=0; j<b->_cnt; j++ )
201 Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );
202 }
203 return *this;
204 }
205
206 //------------------------------Insert----------------------------------------
207 // Insert or replace a key/value pair in the given dictionary. If the
208 // dictionary is too full, it's size is doubled. The prior value being
209 // replaced is returned (NULL if this is a 1st insertion of that key). If
210 // an old value is found, it's swapped with the prior key-value pair on the
211 // list. This moves a commonly searched-for value towards the list head.
212 void *Dict::Insert(void *key, void *val, bool replace) {
213 uint hash = _hash( key ); // Get hash key
214 uint i = hash & (_size-1); // Get hash key, corrected for size
215 bucket *b = &_bin[i]; // Handy shortcut
216 for( uint j=0; j<b->_cnt; j++ ) {
217 if( !_cmp(key,b->_keyvals[j+j]) ) {
218 if (!replace) {
219 return b->_keyvals[j+j+1];
220 } else {
221 void *prior = b->_keyvals[j+j+1];
222 b->_keyvals[j+j ] = key; // Insert current key-value
223 b->_keyvals[j+j+1] = val;
224 return prior; // Return prior
225 }
226 }
227 }
228 if( ++_cnt > _size ) { // Hash table is full
229 doubhash(); // Grow whole table if too full
230 i = hash & (_size-1); // Rehash
231 b = &_bin[i]; // Handy shortcut
232 }
233 if( b->_cnt == b->_max ) { // Must grow bucket?
234 if( !b->_keyvals ) {
235 b->_max = 2; // Initial bucket size
236 b->_keyvals = (void**)_arena->Amalloc_4(sizeof(void*) * b->_max * 2);
237 } else {
238 b->_keyvals = (void**)_arena->Arealloc(b->_keyvals, sizeof(void*) * b->_max * 2, sizeof(void*) * b->_max * 4);
239 b->_max <<= 1; // Double bucket
240 }
241 }
242 b->_keyvals[b->_cnt+b->_cnt ] = key;
243 b->_keyvals[b->_cnt+b->_cnt+1] = val;
244 b->_cnt++;
245 return NULL; // Nothing found prior
246 }
247
248 //------------------------------Delete---------------------------------------
249 // Find & remove a value from dictionary. Return old value.
250 void *Dict::Delete(void *key) {
251 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size
252 bucket *b = &_bin[i]; // Handy shortcut
253 for( uint j=0; j<b->_cnt; j++ )
254 if( !_cmp(key,b->_keyvals[j+j]) ) {
255 void *prior = b->_keyvals[j+j+1];
256 b->_cnt--; // Remove key/value from lo bucket
257 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
258 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
259 _cnt--; // One less thing in table
260 return prior;
261 }
262 return NULL;
263 }
264
265 //------------------------------FindDict-------------------------------------
266 // Find a key-value pair in the given dictionary. If not found, return NULL.
267 // If found, move key-value pair towards head of list.
268 void *Dict::operator [](const void *key) const {
269 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size
270 bucket *b = &_bin[i]; // Handy shortcut
271 for( uint j=0; j<b->_cnt; j++ )
272 if( !_cmp(key,b->_keyvals[j+j]) )
273 return b->_keyvals[j+j+1];
274 return NULL;
275 }
276
277 //------------------------------CmpDict--------------------------------------
278 // CmpDict compares two dictionaries; they must have the same keys (their
279 // keys must match using CmpKey) and they must have the same values (pointer
280 // comparison). If so 1 is returned, if not 0 is returned.
281 int32 Dict::operator ==(const Dict &d2) const {
282 if( _cnt != d2._cnt ) return 0;
283 if( _hash != d2._hash ) return 0;
284 if( _cmp != d2._cmp ) return 0;
285 for( uint i=0; i < _size; i++) { // For complete hash table do
286 bucket *b = &_bin[i]; // Handy shortcut
287 if( b->_cnt != d2._bin[i]._cnt ) return 0;
288 if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )
289 return 0; // Key-value pairs must match
290 }
291 return 1; // All match, is OK
292 }
293
294 //------------------------------print------------------------------------------
295 // Handier print routine
296 void Dict::print() {
297 DictI i(this); // Moved definition in iterator here because of g++.
298 tty->print("Dict@0x%lx[%d] = {", this, _cnt);
299 for( ; i.test(); ++i ) {
300 tty->print("(0x%lx,0x%lx),", i._key, i._value);
301 }
302 tty->print_cr("}");
303 }
304
305 //------------------------------Hashing Functions----------------------------
306 // Convert string to hash key. This algorithm implements a universal hash
307 // function with the multipliers frozen (ok, so it's not universal). The
308 // multipliers (and allowable characters) are all odd, so the resultant sum
309 // is odd - guarenteed not divisible by any power of two, so the hash tables
310 // can be any power of two with good results. Also, I choose multipliers
311 // that have only 2 bits set (the low is always set to be odd) so
312 // multiplication requires only shifts and adds. Characters are required to
313 // be in the range 0-127 (I double & add 1 to force oddness). Keys are
314 // limited to MAXID characters in length. Experimental evidence on 150K of
315 // C text shows excellent spreading of values for any size hash table.
316 int hashstr(const void *t) {
317 register char c, k = 0;
318 register int32 sum = 0;
319 register const char *s = (const char *)t;
320
321 while( ((c = *s++) != '\0') && (k < MAXID-1) ) { // Get characters till null or MAXID-1
322 c = (c<<1)+1; // Characters are always odd!
323 sum += c + (c<<shft[k++]); // Universal hash function
324 }
325 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size
326 }
327
328 //------------------------------hashptr--------------------------------------
329 // Slimey cheap hash function; no guarenteed performance. Better than the
330 // default for pointers, especially on MS-DOS machines.
331 int hashptr(const void *key) {
332 #ifdef __TURBOC__
333 return ((intptr_t)key >> 16);
334 #else // __TURBOC__
335 return ((intptr_t)key >> 2);
336 #endif
337 }
338
339 // Slimey cheap hash function; no guarenteed performance.
340 int hashkey(const void *key) {
341 return (intptr_t)key;
342 }
343
344 //------------------------------Key Comparator Functions---------------------
345 int32 cmpstr(const void *k1, const void *k2) {
346 return strcmp((const char *)k1,(const char *)k2);
347 }
348
349 // Slimey cheap key comparator.
350 int32 cmpkey(const void *key1, const void *key2) {
351 return (int32)((intptr_t)key1 - (intptr_t)key2);
352 }
353
354 //=============================================================================
355 //------------------------------reset------------------------------------------
356 // Create an iterator and initialize the first variables.
357 void DictI::reset( const Dict *dict ) {
358 _d = dict; // The dictionary
359 _i = (uint)-1; // Before the first bin
360 _j = 0; // Nothing left in the current bin
361 ++(*this); // Step to first real value
362 }
363
364 //------------------------------next-------------------------------------------
365 // Find the next key-value pair in the dictionary, or return a NULL key and
366 // value.
367 void DictI::operator ++(void) {
368 if( _j-- ) { // Still working in current bin?
369 _key = _d->_bin[_i]._keyvals[_j+_j];
370 _value = _d->_bin[_i]._keyvals[_j+_j+1];
371 return;
372 }
373
374 while( ++_i < _d->_size ) { // Else scan for non-zero bucket
375 _j = _d->_bin[_i]._cnt;
376 if( !_j ) continue;
377 _j--;
378 _key = _d->_bin[_i]._keyvals[_j+_j];
379 _value = _d->_bin[_i]._keyvals[_j+_j+1];
380 return;
381 }
382 _key = _value = NULL;
383 }