1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)dict2.cpp 1.19 07/05/05 17:04:59 JVM"
3 #endif
4 /*
5 * Copyright 1998-2002 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 // Dictionaries - An Abstract Data Type
29
30 #include "adlc.hpp"
31
32 // #include "dict.hpp"
33
34
35 //------------------------------data-----------------------------------------
36 // String hash tables
37 #define MAXID 20
38 static char initflag = 0; // True after 1st initialization
39 static char shft[MAXID] = {1,2,3,4,5,6,7,1,2,3,4,5,6,7,1,2,3,4,5,6};
40 static short xsum[MAXID + 1];
41
42 //------------------------------bucket---------------------------------------
43 class bucket {
44 public:
45 int _cnt, _max; // Size of bucket
46 const void **_keyvals; // Array of keys and values
47 };
48
49 //------------------------------Dict-----------------------------------------
50 // The dictionary is kept has a hash table. The hash table is a even power
51 // of two, for nice modulo operations. Each bucket in the hash table points
52 // to a linear list of key-value pairs; each key & value is just a (void *).
53 // The list starts with a count. A hash lookup finds the list head, then a
54 // simple linear scan finds the key. If the table gets too full, it's
55 // doubled in size; the total amount of EXTRA times all hash functions are
56 // computed for the doubling is no more than the current size - thus the
57 // doubling in size costs no more than a constant factor in speed.
58 Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp), _arena(NULL) {
59 init();
60 }
61
62 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena) : _hash(inithash), _cmp(initcmp), _arena(arena) {
63 init();
64 }
65
66 void Dict::init() {
67 int i;
68
69 // Precompute table of null character hashes
70 if( !initflag ) { // Not initializated yet?
71 xsum[0] = (1<<shft[0])+1; // Initialize
72 for( i = 1; i < MAXID + 1; i++) {
73 xsum[i] = (1<<shft[i])+1+xsum[i-1];
74 }
75 initflag = 1; // Never again
76 }
77
78 _size = 16; // Size is a power of 2
79 _cnt = 0; // Dictionary is empty
80 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
81 memset(_bin,0,sizeof(bucket)*_size);
82 }
83
84 //------------------------------~Dict------------------------------------------
85 // Delete an existing dictionary.
86 Dict::~Dict() {
87 }
88
89 //------------------------------Clear----------------------------------------
90 // Zap to empty; ready for re-use
91 void Dict::Clear() {
92 _cnt = 0; // Empty contents
93 for( int i=0; i<_size; i++ )
94 _bin[i]._cnt = 0; // Empty buckets, but leave allocated
95 // Leave _size & _bin alone, under the assumption that dictionary will
96 // grow to this size again.
97 }
98
99 //------------------------------doubhash---------------------------------------
100 // Double hash table size. If can't do so, just suffer. If can, then run
101 // thru old hash table, moving things to new table. Note that since hash
102 // table doubled, exactly 1 new bit is exposed in the mask - so everything
103 // in the old table ends up on 1 of two lists in the new table; a hi and a
104 // lo list depending on the value of the bit.
105 void Dict::doubhash(void) {
106 int oldsize = _size;
107 _size <<= 1; // Double in size
108 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );
109 memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );
110 // Rehash things to spread into new table
111 for( int i=0; i < oldsize; i++) { // For complete OLD table do
112 bucket *b = &_bin[i]; // Handy shortcut for _bin[i]
113 if( !b->_keyvals ) continue; // Skip empties fast
114
115 bucket *nb = &_bin[i+oldsize]; // New bucket shortcut
116 int j = b->_max; // Trim new bucket to nearest power of 2
117 while( j > b->_cnt ) j >>= 1; // above old bucket _cnt
118 if( !j ) j = 1; // Handle zero-sized buckets
119 nb->_max = j<<1;
120 // Allocate worst case space for key-value pairs
121 nb->_keyvals = (const void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );
122 int nbcnt = 0;
123
124 for( j=0; j<b->_cnt; j++ ) { // Rehash all keys in this bucket
125 const void *key = b->_keyvals[j+j];
126 if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?
127 nb->_keyvals[nbcnt+nbcnt] = key;
128 nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];
129 nb->_cnt = nbcnt = nbcnt+1;
130 b->_cnt--; // Remove key/value from lo bucket
131 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
132 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
133 j--; // Hash compacted element also
134 }
135 } // End of for all key-value pairs in bucket
136 } // End of for all buckets
137
138
139 }
140
141 //------------------------------Dict-----------------------------------------
142 // Deep copy a dictionary.
143 Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {
144 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
145 memcpy( _bin, d._bin, sizeof(bucket)*_size );
146 for( int i=0; i<_size; i++ ) {
147 if( !_bin[i]._keyvals ) continue;
148 _bin[i]._keyvals=(const void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2);
149 memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));
150 }
151 }
152
153 //------------------------------Dict-----------------------------------------
154 // Deep copy a dictionary.
155 Dict &Dict::operator =( const Dict &d ) {
156 if( _size < d._size ) { // If must have more buckets
157 _arena = d._arena;
158 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );
159 memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
160 _size = d._size;
161 }
162 for( int i=0; i<_size; i++ ) // All buckets are empty
163 _bin[i]._cnt = 0; // But leave bucket allocations alone
164 _cnt = d._cnt;
165 *(Hash*)(&_hash) = d._hash;
166 *(CmpKey*)(&_cmp) = d._cmp;
167 for(int k=0; k<_size; k++ ) {
168 bucket *b = &d._bin[k]; // Shortcut to source bucket
169 for( int j=0; j<b->_cnt; j++ )
170 Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );
171 }
172 return *this;
173 }
174
175 //------------------------------Insert---------------------------------------
176 // Insert or replace a key/value pair in the given dictionary. If the
177 // dictionary is too full, it's size is doubled. The prior value being
178 // replaced is returned (NULL if this is a 1st insertion of that key). If
179 // an old value is found, it's swapped with the prior key-value pair on the
180 // list. This moves a commonly searched-for value towards the list head.
181 const void *Dict::Insert(const void *key, const void *val) {
182 int hash = _hash( key ); // Get hash key
183 int i = hash & (_size-1); // Get hash key, corrected for size
184 bucket *b = &_bin[i]; // Handy shortcut
185 for( int j=0; j<b->_cnt; j++ )
186 if( !_cmp(key,b->_keyvals[j+j]) ) {
187 const void *prior = b->_keyvals[j+j+1];
188 b->_keyvals[j+j ] = key; // Insert current key-value
189 b->_keyvals[j+j+1] = val;
190 return prior; // Return prior
191 }
192
193 if( ++_cnt > _size ) { // Hash table is full
194 doubhash(); // Grow whole table if too full
195 i = hash & (_size-1); // Rehash
196 b = &_bin[i]; // Handy shortcut
197 }
198 if( b->_cnt == b->_max ) { // Must grow bucket?
199 if( !b->_keyvals ) {
200 b->_max = 2; // Initial bucket size
201 b->_keyvals = (const void**)_arena->Amalloc_4( sizeof(void *)*b->_max*2 );
202 } else {
203 b->_keyvals = (const void**)_arena->Arealloc( b->_keyvals, sizeof(void *)*b->_max*2, sizeof(void *)*b->_max*4 );
204 b->_max <<= 1; // Double bucket
205 }
206 }
207 b->_keyvals[b->_cnt+b->_cnt ] = key;
208 b->_keyvals[b->_cnt+b->_cnt+1] = val;
209 b->_cnt++;
210 return NULL; // Nothing found prior
211 }
212
213 //------------------------------Delete---------------------------------------
214 // Find & remove a value from dictionary. Return old value.
215 const void *Dict::Delete(void *key) {
216 int i = _hash( key ) & (_size-1); // Get hash key, corrected for size
217 bucket *b = &_bin[i]; // Handy shortcut
218 for( int j=0; j<b->_cnt; j++ )
219 if( !_cmp(key,b->_keyvals[j+j]) ) {
220 const void *prior = b->_keyvals[j+j+1];
221 b->_cnt--; // Remove key/value from lo bucket
222 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
223 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
224 _cnt--; // One less thing in table
225 return prior;
226 }
227 return NULL;
228 }
229
230 //------------------------------FindDict-------------------------------------
231 // Find a key-value pair in the given dictionary. If not found, return NULL.
232 // If found, move key-value pair towards head of list.
233 const void *Dict::operator [](const void *key) const {
234 int i = _hash( key ) & (_size-1); // Get hash key, corrected for size
235 bucket *b = &_bin[i]; // Handy shortcut
236 for( int j=0; j<b->_cnt; j++ )
237 if( !_cmp(key,b->_keyvals[j+j]) )
238 return b->_keyvals[j+j+1];
239 return NULL;
240 }
241
242 //------------------------------CmpDict--------------------------------------
243 // CmpDict compares two dictionaries; they must have the same keys (their
244 // keys must match using CmpKey) and they must have the same values (pointer
245 // comparison). If so 1 is returned, if not 0 is returned.
246 int Dict::operator ==(const Dict &d2) const {
247 if( _cnt != d2._cnt ) return 0;
248 if( _hash != d2._hash ) return 0;
249 if( _cmp != d2._cmp ) return 0;
250 for( int i=0; i < _size; i++) { // For complete hash table do
251 bucket *b = &_bin[i]; // Handy shortcut
252 if( b->_cnt != d2._bin[i]._cnt ) return 0;
253 if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )
254 return 0; // Key-value pairs must match
255 }
256 return 1; // All match, is OK
257 }
258
259
260 //------------------------------print----------------------------------------
261 static void printvoid(const void* x) { printf("%p", x); }
262 void Dict::print() {
263 print(printvoid, printvoid);
264 }
265 void Dict::print(PrintKeyOrValue print_key, PrintKeyOrValue print_value) {
266 for( int i=0; i < _size; i++) { // For complete hash table do
267 bucket *b = &_bin[i]; // Handy shortcut
268 for( int j=0; j<b->_cnt; j++ ) {
269 print_key( b->_keyvals[j+j ]);
270 printf(" -> ");
271 print_value(b->_keyvals[j+j+1]);
272 printf("\n");
273 }
274 }
275 }
276
277 //------------------------------Hashing Functions----------------------------
278 // Convert string to hash key. This algorithm implements a universal hash
279 // function with the multipliers frozen (ok, so it's not universal). The
280 // multipliers (and allowable characters) are all odd, so the resultant sum
281 // is odd - guarenteed not divisible by any power of two, so the hash tables
282 // can be any power of two with good results. Also, I choose multipliers
283 // that have only 2 bits set (the low is always set to be odd) so
284 // multiplication requires only shifts and adds. Characters are required to
285 // be in the range 0-127 (I double & add 1 to force oddness). Keys are
286 // limited to MAXID characters in length. Experimental evidence on 150K of
287 // C text shows excellent spreading of values for any size hash table.
288 int hashstr(const void *t) {
289 register char c, k = 0;
290 register int sum = 0;
291 register const char *s = (const char *)t;
292
293 while( ((c = s[k]) != '\0') && (k < MAXID-1) ) { // Get characters till nul
294 c = (c<<1)+1; // Characters are always odd!
295 sum += c + (c<<shft[k++]); // Universal hash function
296 }
297 assert( k < (MAXID + 1), "Exceeded maximum name length");
298 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size
299 }
300
301 //------------------------------hashptr--------------------------------------
302 // Slimey cheap hash function; no guarenteed performance. Better than the
303 // default for pointers, especially on MS-DOS machines.
304 int hashptr(const void *key) {
305 #ifdef __TURBOC__
306 return (int)((intptr_t)key >> 16);
307 #else // __TURBOC__
308 return (int)((intptr_t)key >> 2);
309 #endif
310 }
311
312 // Slimey cheap hash function; no guarenteed performance.
313 int hashkey(const void *key) {
314 return (int)((intptr_t)key);
315 }
316
317 //------------------------------Key Comparator Functions---------------------
318 int cmpstr(const void *k1, const void *k2) {
319 return strcmp((const char *)k1,(const char *)k2);
320 }
321
322 // Slimey cheap key comparator.
323 int cmpkey(const void *key1, const void *key2) {
324 return (int)((intptr_t)key1 - (intptr_t)key2);
325 }
326
327 //=============================================================================
328 //------------------------------reset------------------------------------------
329 // Create an iterator and initialize the first variables.
330 void DictI::reset( const Dict *dict ) {
331 _d = dict; // The dictionary
332 _i = (int)-1; // Before the first bin
333 _j = 0; // Nothing left in the current bin
334 ++(*this); // Step to first real value
335 }
336
337 //------------------------------next-------------------------------------------
338 // Find the next key-value pair in the dictionary, or return a NULL key and
339 // value.
340 void DictI::operator ++(void) {
341 if( _j-- ) { // Still working in current bin?
342 _key = _d->_bin[_i]._keyvals[_j+_j];
343 _value = _d->_bin[_i]._keyvals[_j+_j+1];
344 return;
345 }
346
347 while( ++_i < _d->_size ) { // Else scan for non-zero bucket
348 _j = _d->_bin[_i]._cnt;
349 if( !_j ) continue;
350 _j--;
351 _key = _d->_bin[_i]._keyvals[_j+_j];
352 _value = _d->_bin[_i]._keyvals[_j+_j+1];
353 return;
354 }
355 _key = _value = NULL;
356 }
357
358