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comparison src/share/vm/adlc/dict2.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 1998-2002 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 "adlc.hpp"
28
29 // #include "dict.hpp"
30
31
32 //------------------------------data-----------------------------------------
33 // String hash tables
34 #define MAXID 20
35 static char initflag = 0; // True after 1st initialization
36 static char shft[MAXID] = {1,2,3,4,5,6,7,1,2,3,4,5,6,7,1,2,3,4,5,6};
37 static short xsum[MAXID + 1];
38
39 //------------------------------bucket---------------------------------------
40 class bucket {
41 public:
42 int _cnt, _max; // Size of bucket
43 const void **_keyvals; // Array of keys and values
44 };
45
46 //------------------------------Dict-----------------------------------------
47 // The dictionary is kept has a hash table. The hash table is a even power
48 // of two, for nice modulo operations. Each bucket in the hash table points
49 // to a linear list of key-value pairs; each key & value is just a (void *).
50 // The list starts with a count. A hash lookup finds the list head, then a
51 // simple linear scan finds the key. If the table gets too full, it's
52 // doubled in size; the total amount of EXTRA times all hash functions are
53 // computed for the doubling is no more than the current size - thus the
54 // doubling in size costs no more than a constant factor in speed.
55 Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp), _arena(NULL) {
56 init();
57 }
58
59 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena) : _hash(inithash), _cmp(initcmp), _arena(arena) {
60 init();
61 }
62
63 void Dict::init() {
64 int i;
65
66 // Precompute table of null character hashes
67 if( !initflag ) { // Not initializated yet?
68 xsum[0] = (1<<shft[0])+1; // Initialize
69 for( i = 1; i < MAXID + 1; i++) {
70 xsum[i] = (1<<shft[i])+1+xsum[i-1];
71 }
72 initflag = 1; // Never again
73 }
74
75 _size = 16; // Size is a power of 2
76 _cnt = 0; // Dictionary is empty
77 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
78 memset(_bin,0,sizeof(bucket)*_size);
79 }
80
81 //------------------------------~Dict------------------------------------------
82 // Delete an existing dictionary.
83 Dict::~Dict() {
84 }
85
86 //------------------------------Clear----------------------------------------
87 // Zap to empty; ready for re-use
88 void Dict::Clear() {
89 _cnt = 0; // Empty contents
90 for( int i=0; i<_size; i++ )
91 _bin[i]._cnt = 0; // Empty buckets, but leave allocated
92 // Leave _size & _bin alone, under the assumption that dictionary will
93 // grow to this size again.
94 }
95
96 //------------------------------doubhash---------------------------------------
97 // Double hash table size. If can't do so, just suffer. If can, then run
98 // thru old hash table, moving things to new table. Note that since hash
99 // table doubled, exactly 1 new bit is exposed in the mask - so everything
100 // in the old table ends up on 1 of two lists in the new table; a hi and a
101 // lo list depending on the value of the bit.
102 void Dict::doubhash(void) {
103 int oldsize = _size;
104 _size <<= 1; // Double in size
105 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );
106 memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );
107 // Rehash things to spread into new table
108 for( int i=0; i < oldsize; i++) { // For complete OLD table do
109 bucket *b = &_bin[i]; // Handy shortcut for _bin[i]
110 if( !b->_keyvals ) continue; // Skip empties fast
111
112 bucket *nb = &_bin[i+oldsize]; // New bucket shortcut
113 int j = b->_max; // Trim new bucket to nearest power of 2
114 while( j > b->_cnt ) j >>= 1; // above old bucket _cnt
115 if( !j ) j = 1; // Handle zero-sized buckets
116 nb->_max = j<<1;
117 // Allocate worst case space for key-value pairs
118 nb->_keyvals = (const void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );
119 int nbcnt = 0;
120
121 for( j=0; j<b->_cnt; j++ ) { // Rehash all keys in this bucket
122 const void *key = b->_keyvals[j+j];
123 if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?
124 nb->_keyvals[nbcnt+nbcnt] = key;
125 nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];
126 nb->_cnt = nbcnt = nbcnt+1;
127 b->_cnt--; // Remove key/value from lo bucket
128 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
129 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
130 j--; // Hash compacted element also
131 }
132 } // End of for all key-value pairs in bucket
133 } // End of for all buckets
134
135
136 }
137
138 //------------------------------Dict-----------------------------------------
139 // Deep copy a dictionary.
140 Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {
141 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
142 memcpy( _bin, d._bin, sizeof(bucket)*_size );
143 for( int i=0; i<_size; i++ ) {
144 if( !_bin[i]._keyvals ) continue;
145 _bin[i]._keyvals=(const void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2);
146 memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));
147 }
148 }
149
150 //------------------------------Dict-----------------------------------------
151 // Deep copy a dictionary.
152 Dict &Dict::operator =( const Dict &d ) {
153 if( _size < d._size ) { // If must have more buckets
154 _arena = d._arena;
155 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );
156 memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
157 _size = d._size;
158 }
159 for( int i=0; i<_size; i++ ) // All buckets are empty
160 _bin[i]._cnt = 0; // But leave bucket allocations alone
161 _cnt = d._cnt;
162 *(Hash*)(&_hash) = d._hash;
163 *(CmpKey*)(&_cmp) = d._cmp;
164 for(int k=0; k<_size; k++ ) {
165 bucket *b = &d._bin[k]; // Shortcut to source bucket
166 for( int j=0; j<b->_cnt; j++ )
167 Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );
168 }
169 return *this;
170 }
171
172 //------------------------------Insert---------------------------------------
173 // Insert or replace a key/value pair in the given dictionary. If the
174 // dictionary is too full, it's size is doubled. The prior value being
175 // replaced is returned (NULL if this is a 1st insertion of that key). If
176 // an old value is found, it's swapped with the prior key-value pair on the
177 // list. This moves a commonly searched-for value towards the list head.
178 const void *Dict::Insert(const void *key, const void *val) {
179 int hash = _hash( key ); // Get hash key
180 int i = hash & (_size-1); // Get hash key, corrected for size
181 bucket *b = &_bin[i]; // Handy shortcut
182 for( int j=0; j<b->_cnt; j++ )
183 if( !_cmp(key,b->_keyvals[j+j]) ) {
184 const void *prior = b->_keyvals[j+j+1];
185 b->_keyvals[j+j ] = key; // Insert current key-value
186 b->_keyvals[j+j+1] = val;
187 return prior; // Return prior
188 }
189
190 if( ++_cnt > _size ) { // Hash table is full
191 doubhash(); // Grow whole table if too full
192 i = hash & (_size-1); // Rehash
193 b = &_bin[i]; // Handy shortcut
194 }
195 if( b->_cnt == b->_max ) { // Must grow bucket?
196 if( !b->_keyvals ) {
197 b->_max = 2; // Initial bucket size
198 b->_keyvals = (const void**)_arena->Amalloc_4( sizeof(void *)*b->_max*2 );
199 } else {
200 b->_keyvals = (const void**)_arena->Arealloc( b->_keyvals, sizeof(void *)*b->_max*2, sizeof(void *)*b->_max*4 );
201 b->_max <<= 1; // Double bucket
202 }
203 }
204 b->_keyvals[b->_cnt+b->_cnt ] = key;
205 b->_keyvals[b->_cnt+b->_cnt+1] = val;
206 b->_cnt++;
207 return NULL; // Nothing found prior
208 }
209
210 //------------------------------Delete---------------------------------------
211 // Find & remove a value from dictionary. Return old value.
212 const void *Dict::Delete(void *key) {
213 int i = _hash( key ) & (_size-1); // Get hash key, corrected for size
214 bucket *b = &_bin[i]; // Handy shortcut
215 for( int j=0; j<b->_cnt; j++ )
216 if( !_cmp(key,b->_keyvals[j+j]) ) {
217 const void *prior = b->_keyvals[j+j+1];
218 b->_cnt--; // Remove key/value from lo bucket
219 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
220 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
221 _cnt--; // One less thing in table
222 return prior;
223 }
224 return NULL;
225 }
226
227 //------------------------------FindDict-------------------------------------
228 // Find a key-value pair in the given dictionary. If not found, return NULL.
229 // If found, move key-value pair towards head of list.
230 const void *Dict::operator [](const void *key) const {
231 int i = _hash( key ) & (_size-1); // Get hash key, corrected for size
232 bucket *b = &_bin[i]; // Handy shortcut
233 for( int j=0; j<b->_cnt; j++ )
234 if( !_cmp(key,b->_keyvals[j+j]) )
235 return b->_keyvals[j+j+1];
236 return NULL;
237 }
238
239 //------------------------------CmpDict--------------------------------------
240 // CmpDict compares two dictionaries; they must have the same keys (their
241 // keys must match using CmpKey) and they must have the same values (pointer
242 // comparison). If so 1 is returned, if not 0 is returned.
243 int Dict::operator ==(const Dict &d2) const {
244 if( _cnt != d2._cnt ) return 0;
245 if( _hash != d2._hash ) return 0;
246 if( _cmp != d2._cmp ) return 0;
247 for( int i=0; i < _size; i++) { // For complete hash table do
248 bucket *b = &_bin[i]; // Handy shortcut
249 if( b->_cnt != d2._bin[i]._cnt ) return 0;
250 if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )
251 return 0; // Key-value pairs must match
252 }
253 return 1; // All match, is OK
254 }
255
256
257 //------------------------------print----------------------------------------
258 static void printvoid(const void* x) { printf("%p", x); }
259 void Dict::print() {
260 print(printvoid, printvoid);
261 }
262 void Dict::print(PrintKeyOrValue print_key, PrintKeyOrValue print_value) {
263 for( int i=0; i < _size; i++) { // For complete hash table do
264 bucket *b = &_bin[i]; // Handy shortcut
265 for( int j=0; j<b->_cnt; j++ ) {
266 print_key( b->_keyvals[j+j ]);
267 printf(" -> ");
268 print_value(b->_keyvals[j+j+1]);
269 printf("\n");
270 }
271 }
272 }
273
274 //------------------------------Hashing Functions----------------------------
275 // Convert string to hash key. This algorithm implements a universal hash
276 // function with the multipliers frozen (ok, so it's not universal). The
277 // multipliers (and allowable characters) are all odd, so the resultant sum
278 // is odd - guarenteed not divisible by any power of two, so the hash tables
279 // can be any power of two with good results. Also, I choose multipliers
280 // that have only 2 bits set (the low is always set to be odd) so
281 // multiplication requires only shifts and adds. Characters are required to
282 // be in the range 0-127 (I double & add 1 to force oddness). Keys are
283 // limited to MAXID characters in length. Experimental evidence on 150K of
284 // C text shows excellent spreading of values for any size hash table.
285 int hashstr(const void *t) {
286 register char c, k = 0;
287 register int sum = 0;
288 register const char *s = (const char *)t;
289
290 while( ((c = s[k]) != '\0') && (k < MAXID-1) ) { // Get characters till nul
291 c = (c<<1)+1; // Characters are always odd!
292 sum += c + (c<<shft[k++]); // Universal hash function
293 }
294 assert( k < (MAXID + 1), "Exceeded maximum name length");
295 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size
296 }
297
298 //------------------------------hashptr--------------------------------------
299 // Slimey cheap hash function; no guarenteed performance. Better than the
300 // default for pointers, especially on MS-DOS machines.
301 int hashptr(const void *key) {
302 #ifdef __TURBOC__
303 return (int)((intptr_t)key >> 16);
304 #else // __TURBOC__
305 return (int)((intptr_t)key >> 2);
306 #endif
307 }
308
309 // Slimey cheap hash function; no guarenteed performance.
310 int hashkey(const void *key) {
311 return (int)((intptr_t)key);
312 }
313
314 //------------------------------Key Comparator Functions---------------------
315 int cmpstr(const void *k1, const void *k2) {
316 return strcmp((const char *)k1,(const char *)k2);
317 }
318
319 // Slimey cheap key comparator.
320 int cmpkey(const void *key1, const void *key2) {
321 return (int)((intptr_t)key1 - (intptr_t)key2);
322 }
323
324 //=============================================================================
325 //------------------------------reset------------------------------------------
326 // Create an iterator and initialize the first variables.
327 void DictI::reset( const Dict *dict ) {
328 _d = dict; // The dictionary
329 _i = (int)-1; // Before the first bin
330 _j = 0; // Nothing left in the current bin
331 ++(*this); // Step to first real value
332 }
333
334 //------------------------------next-------------------------------------------
335 // Find the next key-value pair in the dictionary, or return a NULL key and
336 // value.
337 void DictI::operator ++(void) {
338 if( _j-- ) { // Still working in current bin?
339 _key = _d->_bin[_i]._keyvals[_j+_j];
340 _value = _d->_bin[_i]._keyvals[_j+_j+1];
341 return;
342 }
343
344 while( ++_i < _d->_size ) { // Else scan for non-zero bucket
345 _j = _d->_bin[_i]._cnt;
346 if( !_j ) continue;
347 _j--;
348 _key = _d->_bin[_i]._keyvals[_j+_j];
349 _value = _d->_bin[_i]._keyvals[_j+_j+1];
350 return;
351 }
352 _key = _value = NULL;
353 }