Annotation of parser3/src/include/pa_hash.h, revision 1.62
1.28 paf 1: /** @file
1.29 paf 2: Parser: hash class decl.
3:
1.62 ! paf 4: Copyright (c) 2001-2004 ArtLebedev Group (http://www.artlebedev.com)
1.29 paf 5:
1.54 paf 6: Author: Alexandr Petrosian <paf@design.ru> (http://paf.design.ru)
1.1 paf 7: */
8:
1.59 paf 9: /*
10: The prime numbers used from zend_hash.c,
11: the part of Zend scripting engine library,
12: Copyrighted (C) 1999-2000 Zend Technologies Ltd.
13: http://www.zend.com/license/0_92.txt
14: For more information about Zend please visit http://www.zend.com/
15: */
16:
1.1 paf 17: #ifndef PA_HASH_H
18: #define PA_HASH_H
1.56 paf 19:
1.62 ! paf 20: static const char * const IDENT_HASH_H="$Date: 2003/11/24 11:32:14 $";
1.1 paf 21:
1.59 paf 22: #include "pa_memory.h"
1.1 paf 23: #include "pa_types.h"
1.59 paf 24:
25: const int HASH_ALLOCATES_COUNT=29;
1.1 paf 26:
1.61 paf 27: /** Zend comment: Generated on an Octa-ALPHA 300MHz CPU & 2.5GB RAM monster
28:
29: paf: HPUX ld could not handle static member: unsatisfied symbols
30: */
31: static uint Hash_allocates[HASH_ALLOCATES_COUNT]={
32: 5, 11, 19, 53, 107, 223, 463, 983, 1979, 3907, 7963,
33: 16229, 32531, 65407, 130987, 262237, 524521, 1048793,
34: 2097397, 4194103, 8388857, 16777447, 33554201, 67108961,
35: 134217487, 268435697, 536870683, 1073741621, 2147483399};
36:
1.29 paf 37: /**
1.59 paf 38: Simple hash.
1.29 paf 39:
1.59 paf 40: Automatically rehashed when almost is_full.
1.51 paf 41: Contains no 0 values.
42: get returning 0 means there were no such.
43: "put value 0" means "remove"
1.29 paf 44: */
1.59 paf 45: template<typename K, typename V> class Hash: public PA_Object {
1.1 paf 46: public:
47:
1.59 paf 48: typedef K key_type;
49: typedef V value_type;
1.3 paf 50:
1.59 paf 51: Hash() {
1.61 paf 52: allocated=Hash_allocates[allocates_index=0];
1.59 paf 53: threshold=allocated*THRESHOLD_PERCENT/100;
54: fpairs_count=fused_refs=0;
55: refs=new(UseGC) Pair*[allocated];
56: }
1.25 paf 57:
1.59 paf 58: Hash(const Hash& source) {
59: allocates_index=source.allocates_index;
60: allocated=source.allocated;
61: threshold=source.threshold;
62: fused_refs=source.fused_refs;
63: fpairs_count=source.fpairs_count;
64: refs=new(UseGC) Pair*[allocated];
65:
66: // clone & rehash
67: Pair **old_ref=source.refs;
68: for(int index=0; index<allocated; index++)
69: for(Pair *pair=*old_ref++; pair; ) {
70: Pair *next=pair->link;
1.45 paf 71:
1.59 paf 72: Pair **new_ref=&refs[index];
73: *new_ref=new Pair(pair->code, pair->key, pair->value, *new_ref);
1.38 paf 74:
1.59 paf 75: pair=next;
76: }
1.43 parser 77: }
78:
1.59 paf 79: /// put a [value] under the [key] @returns existed or not
80: bool put(K key, V value) {
81: if(!value) {
82: remove(key);
83: return false;
84: }
85: if(is_full())
86: expand();
87:
88: uint code=hash_code(key);
89: uint index=code%allocated;
90: Pair **ref=&refs[index];
91: for(Pair *pair=*ref; pair; pair=pair->link)
92: if(pair->code==code && pair->key==key) {
93: // found a pair with the same key
94: pair->value=value;
95: return true;
96: }
97:
98: // proper pair not found -- create&link_in new pair
99: if(!*ref) // root cell were fused_refs?
100: fused_refs++; // not, we'll use it and record the fact
101: *ref=new Pair(code, key, value, *ref);
102: fpairs_count++;
103: return false;
1.24 paf 104: }
1.10 paf 105:
1.59 paf 106: /// remove the [key] @returns existed or not
107: bool remove(K key) {
108: uint code=hash_code(key);
109: uint index=code%allocated;
110: for(Pair **ref=&refs[index]; *ref; ref=&(*ref)->link)
111: if((*ref)->code==code && (*ref)->key==key) {
112: // found a pair with the same key
113: Pair *next=(*ref)->link;
114: delete *ref;
115: *ref=next;
116: --fpairs_count;
117: return true;
118: }
1.8 paf 119:
1.59 paf 120: return false;
121: }
1.48 paf 122:
1.59 paf 123: /// get associated [value] by the [key]
124: V get(K key) const {
125: uint code=hash_code(key);
126: uint index=code%allocated;
127: for(Pair *pair=refs[index]; pair; pair=pair->link)
128: if(pair->code==code && pair->key==key)
129: return pair->value;
130:
131: return V(0);
1.33 paf 132: }
1.17 paf 133:
1.51 paf 134: /// put a [value] under the [key] if that [key] existed @returns existed or not
1.59 paf 135: bool put_replace(K key, V value) {
136: if(!value) {
137: remove(key);
138: return false;
139: }
140: uint code=hash_code(key);
141: uint index=code%allocated;
142: for(Pair *pair=refs[index]; pair; pair=pair->link)
143: if(pair->code==code && pair->key==key) {
144: // found a pair with the same key, replacing
145: pair->value=value;
146: return true;
147: }
148:
149: // proper pair not found
150: return false;
151: }
1.18 paf 152:
1.51 paf 153: /// put a [value] under the [key] if that [key] NOT existed @returns existed or not
1.59 paf 154: bool put_dont_replace(K key, V value) {
155: if(!value) {
156: remove(key);
157: return false;
158: }
159: if(is_full())
160: expand();
161:
162: uint code=hash_code(key);
163: uint index=code%allocated;
164: Pair **ref=&refs[index];
165: for(Pair *pair=*ref; pair; pair=pair->link)
166: if(pair->code==code && pair->key==key) {
167: // found a pair with the same key, NOT replacing
168: return true;
169: }
170:
171: // proper pair not found -- create&link_in new pair
172: if(!*ref) // root cell were fused_refs?
173: fused_refs++; // not, we'll use it and record the fact
174: *ref=new Pair(code, key, value, *ref);
175: fpairs_count++;
176: return false;
177: }
1.18 paf 178:
1.59 paf 179: /** put all 'src' values if NO with same key existed
180: @todo optimize this.allocated==src.allocated case
181: */
182: void merge_dont_replace(const Hash& src) {
183: for(int i=0; i<src.allocated; i++)
184: for(Pair *pair=src.refs[i]; pair; pair=pair->link)
185: put_dont_replace(pair->key, pair->value);
1.36 paf 186: }
1.11 paf 187:
1.29 paf 188: /// number of elements in hash
1.59 paf 189: int count() const { return fpairs_count; }
1.25 paf 190:
1.59 paf 191: /// iterate over all pairs
192: template<typename I> void for_each(void callback(K, V, I), I info) const {
193: Pair **ref=refs;
194: for(int index=0; index<allocated; index++)
195: for(Pair *pair=*ref++; pair; pair=pair->link)
196: callback(pair->key, pair->value, info);
197: }
1.45 paf 198:
1.59 paf 199: /// iterate over all pairs
200: template<typename I> void for_each_ref(void callback(K, V&, I), I info) const {
201: Pair **ref=refs;
202: for(int index=0; index<allocated; index++)
203: for(Pair *pair=*ref++; pair; pair=pair->link)
204: callback(pair->key, pair->value, info);
205: }
1.38 paf 206:
1.59 paf 207: /// iterate over all pairs until condition becomes true, return that element
208: template<typename I> V first_that(bool callback(K, V, I), I info) const {
209: Pair **ref=refs;
210: for(int index=0; index<allocated; index++)
211: for(Pair *pair=*ref++; pair; pair=pair->link)
212: if(callback(pair->key, pair->value, info))
213: return pair->value;
214:
215: return V(0);
216: }
1.27 paf 217:
1.29 paf 218: /// remove all elements
1.59 paf 219: void clear() {
220: memset(refs, 0, sizeof(*refs)*allocated);
221: fpairs_count=fused_refs=0;
222: }
1.15 paf 223:
1.1 paf 224: private:
225:
1.39 paf 226: /// expand when these %% of allocated exausted
1.1 paf 227: enum {
228: THRESHOLD_PERCENT=75
229: };
1.9 paf 230:
1.61 paf 231: /// the index of [allocated] in [Hash_allocates]
1.19 paf 232: int allocates_index;
1.1 paf 233:
1.39 paf 234: /// number of allocated pairs
1.19 paf 235: int allocated;
1.1 paf 236:
1.59 paf 237: /// helper: expanding when fused_refs == threshold
1.1 paf 238: int threshold;
239:
1.39 paf 240: /// used pairs
1.59 paf 241: int fused_refs;
1.44 parser 242:
243: /// stored pairs total (including those by links)
1.59 paf 244: int fpairs_count;
1.1 paf 245:
1.39 paf 246: /// pair storage
1.59 paf 247: class Pair: public PA_Allocated {
248: public:
1.1 paf 249: uint code;
1.59 paf 250: K key;
251: V value;
1.1 paf 252: Pair *link;
1.2 paf 253:
1.59 paf 254: Pair(uint acode, K akey, V avalue, Pair *alink) :
1.1 paf 255: code(acode),
256: key(akey),
257: value(avalue),
1.2 paf 258: link(alink) {}
259: } **refs;
1.1 paf 260:
1.39 paf 261: /// filled to threshold: needs expanding
1.59 paf 262: bool is_full() { return fused_refs==threshold; }
1.5 paf 263:
1.39 paf 264: /// allocate larger buffer & rehash
1.59 paf 265: void expand() {
266: int old_allocated=allocated;
267: Pair **old_refs=refs;
268:
269: allocates_index=allocates_index+1<HASH_ALLOCATES_COUNT?allocates_index+1:HASH_ALLOCATES_COUNT-1;
270: // allocated bigger refs array
1.61 paf 271: allocated=Hash_allocates[allocates_index];
1.59 paf 272: threshold=allocated*THRESHOLD_PERCENT/100;
273: refs=new(UseGC) Pair*[allocated];
274:
275: // rehash
276: Pair **old_ref=old_refs;
277: for(int old_index=0; old_index<old_allocated; old_index++)
278: for(Pair *pair=*old_ref++; pair; ) {
279: Pair *next=pair->link;
280:
281: uint new_index=pair->code%allocated;
282: Pair **new_ref=&refs[new_index];
283: pair->link=*new_ref;
284: *new_ref=pair;
285:
286: pair=next;
287: }
288:
289: delete[] old_refs;
290: }
1.4 paf 291:
292: private: //disabled
293:
1.12 paf 294: Hash& operator = (const Hash&) { return *this; }
1.1 paf 295: };
1.59 paf 296:
297: /// useful generic hash function
298: inline void generic_hash_code(uint& result, char c) {
299: result=(result<<4)+c;
300: if(uint g=(result&0xF0000000)) {
301: result=result^(g>>24);
302: result=result^g;
303: }
304: }
305: /// useful generic hash function
306: inline void generic_hash_code(uint& result, const char* s) {
307: while(char c=*s++) {
308: result=(result<<4)+c;
309: if(uint g=(result&0xF0000000)) {
310: result=result^(g>>24);
311: result=result^g;
312: }
313: }
314: }
315:
316: /// useful generic hash function
317: inline void generic_hash_code(uint& result, const char* buf, size_t size) {
318: const char* end=buf+size;
319: while(buf<end) {
320: result=(result<<4)+*buf++;
321: if(uint g=(result&0xF0000000)) {
322: result=result^(g>>24);
323: result=result^g;
324: }
325: }
326: }
327:
328: /// simple hash code of int. used by EXIF mapping
329: inline uint hash_code(int self) {
330: uint result=0;
331: generic_hash_code(result, (const char*)&self, sizeof(self));
332: return result;
333: }
334:
335: /// Auto-object used to temporarily substituting/removing hash values
336: template <typename K, typename V>
1.55 paf 337: class Temp_hash_value {
1.59 paf 338: Hash<K, V>& fhash;
339: K fname;
340: V saved_value;
1.55 paf 341: public:
1.59 paf 342: Temp_hash_value(Hash<K, V>& ahash, K aname, V avalue) :
1.55 paf 343: fhash(ahash),
344: fname(aname),
345: saved_value(ahash.get(aname)) {
346: fhash.put(aname, avalue);
347: }
348: ~Temp_hash_value() {
349: fhash.put(fname, saved_value);
350: }
351: };
1.1 paf 352:
353: #endif
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