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-rwxr-xr-xnoncore/apps/opie-reader/hash.h201
1 files changed, 201 insertions, 0 deletions
diff --git a/noncore/apps/opie-reader/hash.h b/noncore/apps/opie-reader/hash.h
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1#ifndef __HASH_H
2#define __HASH_H
3
4#include <stdlib.h>
5/* Primes
61 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
7101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181
8191 193 197 199 211 223 227 229 233 239 241 251 257 263 269 271 277
9281 283 293 307 311 313 317 331 337 347 349 353 359 367 373 379 383
10389 397 401 409 419 421 431 433 439 443 449 457 461 463 467 479 487
11491 499 503 509 521 523 541 547 557 563 569 571 577 587 593 599 601
12607 613 617 619 631 641 643 647 653 659 661 673 677 683 691 701 709
13719 727 733 739 743 751 757 761 769 773 787 797 809 811 821 823 827
14829 839 853 857 859 863 877 881 883 887 907 911 919 929 937 941 947
15953 967 971 977 983 991 997
16*/
17
18inline size_t hashfn(unsigned long l)
19{
20 return l*0x33f3;
21}
22
23inline size_t hash2fn(unsigned long l)
24{
25 return l & 7;
26}
27/*/
28template<class K>size_t hashfn(const K& l)
29{
30 size_t s = 0;
31 unsigned char* p = (unsigned char*)&l;
32 for (int i = 0; i < sizeof(K)-1; i++)
33 {
34 s = 3*s+(255-p[i]);
35 }
36}
37
38template<class K>size_t hash2fn(const K& l)
39{
40 unsigned char* p = (unsigned char*)&l;
41 return 255-p[sizeof(K)-1];
42}
43*/
44template<class K, class D>
45class hashtable
46{
47 public:
48 class iterator;
49 friend class hashtable::iterator;
50#ifndef _WINDOWS
51 private:
52#endif
53 struct keydata
54 {
55 K key;
56 D data;
57 bool inuse;
58 keydata() : inuse(false) {}
59 keydata(K k, D d) : key(k), data(d), inuse(true) {}
60 };
61 keydata* table;
62 size_t hshsz;
63 bool notprime(size_t p)
64 {
65 size_t d;
66 if (p % 2 == 0) return true;
67 d = 3;
68 while (d*d <= p)
69 {
70 if (p % d == 0)
71 {
72 return true;
73 }
74 d += 2;
75 }
76 return false;
77 }
78 void resize()
79 {
80 size_t oldsz = hshsz;
81 hshsz = (3*hshsz)/2;
82 while (notprime(hshsz))
83 {
84 hshsz++;
85 }
86 //printf("Size:%u\n", hshsz);
87 keydata* oldtable = table;
88 table = new keydata[hshsz];
89 for (size_t i = 0; i < oldsz; i++)
90 {
91 if (oldtable[i].inuse)
92 {
93 //printf("Setting %u to %u\n", oldtable[i].key, oldtable[i].data);
94 (*this)[oldtable[i].key] = oldtable[i].data;
95 //printf("Now %u is %u\n", oldtable[i].key, (*this)[oldtable[i].key]);
96 }
97 }
98 delete [] oldtable;
99 }
100 size_t findkey(const K& key) // returns -1 if can't find it
101 {
102 size_t hash2 = hash2fn(key)%(hshsz-1)+1;
103 size_t hash = hashfn(key) % hshsz;
104 size_t i = hash;
105 //printf("Key:%u, hash:%u, hash2:%u\n", key, hash, hash2);
106 while (table[i].inuse) // !empty
107 {
108 if (table[i].key == key)
109 {
110 //printf("Key %u present at %u\n", key, i);
111 return i; // but its the correct one & present
112 }
113 i = (i+hash2) % hshsz;
114 if (i == hash) // Table full
115 {
116 resize();
117 hash2 = hash2fn(key)%(hshsz-1)+1;
118 hash = hashfn(key) % hshsz;
119 i = hash;
120 //printf("(R)Key:%u, hash:%u, hash2:%u\n", key, hash, hash2);
121 }
122 }
123 //printf("Key %u absent at %u\n", key, i);
124 return i; // found & absent
125 }
126 public:
127 hashtable(int sz) : hshsz(sz)
128 {
129 while (notprime(hshsz))
130 {
131 hshsz++;
132 }
133 //printf("Size:%u\n", hshsz);
134 table = new keydata[hshsz];
135 }
136 ~hashtable()
137 {
138 delete [] table;
139 }
140 D& operator[](K k)
141 {
142 int i = findkey(k);
143 table[i].key = k;
144 table[i].inuse = true;
145 return table[i].data;
146 }
147 class iterator
148 {
149 friend class hashtable;
150#ifdef _WINDOWS
151 public:
152#endif
153 unsigned int ptr;
154 hashtable* tab;
155 iterator(int t, hashtable* _tab) : ptr(t), tab(_tab)
156 {
157 while (!tab->table[ptr].inuse && ptr < tab->hshsz)
158 {
159 ptr++;
160 }
161 }
162 public:
163 iterator() : tab(NULL) {}
164 iterator operator++()
165 {
166 while (++ptr < tab->hshsz)
167 {
168 if (tab->table[ptr].inuse) return *this;
169 }
170 return *this;
171 }
172 iterator& operator=(const iterator& r)
173 {
174 ptr = r.ptr;
175 tab = r.tab;
176 return *this;
177 }
178 bool operator!=(const iterator& r)
179 {
180 return !((ptr == r.ptr) && (tab == r.tab));
181 }
182 bool operator==(const iterator& r)
183 {
184 return ((ptr == r.ptr) && (tab == r.tab));
185 }
186 K first() { return tab->table[ptr].key; }
187 D second() { return tab->table[ptr].data; }
188 };
189 iterator find(K k)
190 {
191 size_t i = findkey(k);
192 return (table[i].inuse) ? iterator(i,this) : end();
193 }
194 D& operator[](const iterator& i) // Never call with an invalid iterator!
195 {
196 return table[i.ptr].data;
197 }
198 iterator begin() { return iterator(0, this); }
199 iterator end() { return iterator(hshsz, this); }
200};
201#endif