Annotation of parser3/src/include/pa_hash.h, revision 1.63
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:
1.63 ! paf 20: static const char * const IDENT_HASH_H="$Date: 2004/02/11 15:33:14 $";
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:
1.63 ! paf 106: /// put a [value] under the [key] @returns existed or not
! 107: template<typename R, typename F> R maybe_put(K key, V value, F prevent) {
! 108: if(!value) {
! 109: remove(key);
! 110: return 0;
! 111: }
! 112: if(is_full())
! 113: expand();
! 114:
! 115: uint code=hash_code(key);
! 116: uint index=code%allocated;
! 117: Pair **ref=&refs[index];
! 118: for(Pair *pair=*ref; pair; pair=pair->link)
! 119: if(pair->code==code && pair->key==key) {
! 120: // found a pair with the same key
! 121:
! 122: // prevent-function intercepted put?
! 123: if(R result=prevent(pair->value))
! 124: return result;
! 125:
! 126: pair->value=value;
! 127: return reinterpret_cast<R>(1);
! 128: }
! 129:
! 130: // proper pair not found -- create&link_in new pair
! 131: if(!*ref) // root cell were fused_refs?
! 132: fused_refs++; // not, we'll use it and record the fact
! 133: *ref=new Pair(code, key, value, *ref);
! 134: fpairs_count++;
! 135: return 0;
! 136: }
! 137:
1.59 paf 138: /// remove the [key] @returns existed or not
139: bool remove(K key) {
140: uint code=hash_code(key);
141: uint index=code%allocated;
142: for(Pair **ref=&refs[index]; *ref; ref=&(*ref)->link)
143: if((*ref)->code==code && (*ref)->key==key) {
144: // found a pair with the same key
145: Pair *next=(*ref)->link;
146: delete *ref;
147: *ref=next;
148: --fpairs_count;
149: return true;
150: }
1.8 paf 151:
1.59 paf 152: return false;
153: }
1.48 paf 154:
1.59 paf 155: /// get associated [value] by the [key]
156: V get(K key) const {
157: uint code=hash_code(key);
158: uint index=code%allocated;
159: for(Pair *pair=refs[index]; pair; pair=pair->link)
160: if(pair->code==code && pair->key==key)
161: return pair->value;
162:
163: return V(0);
1.33 paf 164: }
1.17 paf 165:
1.51 paf 166: /// put a [value] under the [key] if that [key] existed @returns existed or not
1.63 ! paf 167: bool put_replaced(K key, V value) {
1.59 paf 168: if(!value) {
169: remove(key);
170: return false;
171: }
172: uint code=hash_code(key);
173: uint index=code%allocated;
174: for(Pair *pair=refs[index]; pair; pair=pair->link)
175: if(pair->code==code && pair->key==key) {
176: // found a pair with the same key, replacing
177: pair->value=value;
178: return true;
179: }
180:
181: // proper pair not found
182: return false;
183: }
1.18 paf 184:
1.51 paf 185: /// put a [value] under the [key] if that [key] NOT existed @returns existed or not
1.59 paf 186: bool put_dont_replace(K key, V value) {
187: if(!value) {
188: remove(key);
189: return false;
190: }
191: if(is_full())
192: expand();
193:
194: uint code=hash_code(key);
195: uint index=code%allocated;
196: Pair **ref=&refs[index];
197: for(Pair *pair=*ref; pair; pair=pair->link)
198: if(pair->code==code && pair->key==key) {
199: // found a pair with the same key, NOT replacing
200: return true;
201: }
202:
203: // proper pair not found -- create&link_in new pair
204: if(!*ref) // root cell were fused_refs?
205: fused_refs++; // not, we'll use it and record the fact
206: *ref=new Pair(code, key, value, *ref);
207: fpairs_count++;
208: return false;
209: }
1.18 paf 210:
1.59 paf 211: /** put all 'src' values if NO with same key existed
212: @todo optimize this.allocated==src.allocated case
213: */
214: void merge_dont_replace(const Hash& src) {
215: for(int i=0; i<src.allocated; i++)
216: for(Pair *pair=src.refs[i]; pair; pair=pair->link)
217: put_dont_replace(pair->key, pair->value);
1.36 paf 218: }
1.11 paf 219:
1.29 paf 220: /// number of elements in hash
1.59 paf 221: int count() const { return fpairs_count; }
1.25 paf 222:
1.59 paf 223: /// iterate over all pairs
224: template<typename I> void for_each(void callback(K, V, I), I info) const {
225: Pair **ref=refs;
226: for(int index=0; index<allocated; index++)
227: for(Pair *pair=*ref++; pair; pair=pair->link)
228: callback(pair->key, pair->value, info);
229: }
1.45 paf 230:
1.59 paf 231: /// iterate over all pairs
232: template<typename I> void for_each_ref(void callback(K, V&, I), I info) const {
233: Pair **ref=refs;
234: for(int index=0; index<allocated; index++)
235: for(Pair *pair=*ref++; pair; pair=pair->link)
236: callback(pair->key, pair->value, info);
237: }
1.38 paf 238:
1.59 paf 239: /// iterate over all pairs until condition becomes true, return that element
240: template<typename I> V first_that(bool callback(K, V, I), I info) const {
241: Pair **ref=refs;
242: for(int index=0; index<allocated; index++)
243: for(Pair *pair=*ref++; pair; pair=pair->link)
244: if(callback(pair->key, pair->value, info))
245: return pair->value;
246:
247: return V(0);
248: }
1.27 paf 249:
1.29 paf 250: /// remove all elements
1.59 paf 251: void clear() {
252: memset(refs, 0, sizeof(*refs)*allocated);
253: fpairs_count=fused_refs=0;
254: }
1.15 paf 255:
1.1 paf 256: private:
257:
1.39 paf 258: /// expand when these %% of allocated exausted
1.1 paf 259: enum {
260: THRESHOLD_PERCENT=75
261: };
1.9 paf 262:
1.61 paf 263: /// the index of [allocated] in [Hash_allocates]
1.19 paf 264: int allocates_index;
1.1 paf 265:
1.39 paf 266: /// number of allocated pairs
1.19 paf 267: int allocated;
1.1 paf 268:
1.59 paf 269: /// helper: expanding when fused_refs == threshold
1.1 paf 270: int threshold;
271:
1.39 paf 272: /// used pairs
1.59 paf 273: int fused_refs;
1.44 parser 274:
275: /// stored pairs total (including those by links)
1.59 paf 276: int fpairs_count;
1.1 paf 277:
1.39 paf 278: /// pair storage
1.59 paf 279: class Pair: public PA_Allocated {
280: public:
1.1 paf 281: uint code;
1.59 paf 282: K key;
283: V value;
1.1 paf 284: Pair *link;
1.2 paf 285:
1.59 paf 286: Pair(uint acode, K akey, V avalue, Pair *alink) :
1.1 paf 287: code(acode),
288: key(akey),
289: value(avalue),
1.2 paf 290: link(alink) {}
291: } **refs;
1.1 paf 292:
1.39 paf 293: /// filled to threshold: needs expanding
1.59 paf 294: bool is_full() { return fused_refs==threshold; }
1.5 paf 295:
1.39 paf 296: /// allocate larger buffer & rehash
1.59 paf 297: void expand() {
298: int old_allocated=allocated;
299: Pair **old_refs=refs;
300:
301: allocates_index=allocates_index+1<HASH_ALLOCATES_COUNT?allocates_index+1:HASH_ALLOCATES_COUNT-1;
302: // allocated bigger refs array
1.61 paf 303: allocated=Hash_allocates[allocates_index];
1.59 paf 304: threshold=allocated*THRESHOLD_PERCENT/100;
305: refs=new(UseGC) Pair*[allocated];
306:
307: // rehash
308: Pair **old_ref=old_refs;
309: for(int old_index=0; old_index<old_allocated; old_index++)
310: for(Pair *pair=*old_ref++; pair; ) {
311: Pair *next=pair->link;
312:
313: uint new_index=pair->code%allocated;
314: Pair **new_ref=&refs[new_index];
315: pair->link=*new_ref;
316: *new_ref=pair;
317:
318: pair=next;
319: }
320:
321: delete[] old_refs;
322: }
1.4 paf 323:
324: private: //disabled
325:
1.12 paf 326: Hash& operator = (const Hash&) { return *this; }
1.1 paf 327: };
1.59 paf 328:
329: /// useful generic hash function
330: inline void generic_hash_code(uint& result, char c) {
331: result=(result<<4)+c;
332: if(uint g=(result&0xF0000000)) {
333: result=result^(g>>24);
334: result=result^g;
335: }
336: }
337: /// useful generic hash function
338: inline void generic_hash_code(uint& result, const char* s) {
339: while(char c=*s++) {
340: result=(result<<4)+c;
341: if(uint g=(result&0xF0000000)) {
342: result=result^(g>>24);
343: result=result^g;
344: }
345: }
346: }
347:
348: /// useful generic hash function
349: inline void generic_hash_code(uint& result, const char* buf, size_t size) {
350: const char* end=buf+size;
351: while(buf<end) {
352: result=(result<<4)+*buf++;
353: if(uint g=(result&0xF0000000)) {
354: result=result^(g>>24);
355: result=result^g;
356: }
357: }
358: }
359:
360: /// simple hash code of int. used by EXIF mapping
361: inline uint hash_code(int self) {
362: uint result=0;
363: generic_hash_code(result, (const char*)&self, sizeof(self));
364: return result;
365: }
366:
367: /// Auto-object used to temporarily substituting/removing hash values
368: template <typename K, typename V>
1.55 paf 369: class Temp_hash_value {
1.59 paf 370: Hash<K, V>& fhash;
371: K fname;
372: V saved_value;
1.55 paf 373: public:
1.59 paf 374: Temp_hash_value(Hash<K, V>& ahash, K aname, V avalue) :
1.55 paf 375: fhash(ahash),
376: fname(aname),
377: saved_value(ahash.get(aname)) {
378: fhash.put(aname, avalue);
379: }
380: ~Temp_hash_value() {
381: fhash.put(fname, saved_value);
382: }
383: };
1.1 paf 384:
385: #endif
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