Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 1 | /* Copyright 1996,1997,2001,2002,2009 Alain Knaff. |
| 2 | * This file is part of mtools. |
| 3 | * |
| 4 | * Mtools is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation, either version 3 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * Mtools is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with Mtools. If not, see <http://www.gnu.org/licenses/>. |
| 16 | * |
| 17 | * hash.c - hash table. |
| 18 | */ |
| 19 | |
| 20 | #include "sysincludes.h" |
| 21 | #include "htable.h" |
| 22 | #include "mtools.h" |
| 23 | |
| 24 | struct hashtable { |
| 25 | T_HashFunc f1,f2; |
| 26 | T_ComparFunc compar; |
| 27 | size_t size; /* actual size of the array */ |
| 28 | size_t fill; /* number of deleted or in use slots */ |
| 29 | size_t inuse; /* number of slots in use */ |
| 30 | size_t max; /* maximal number of elements to keep efficient */ |
| 31 | T_HashTableEl *entries; |
| 32 | }; |
| 33 | |
| 34 | static size_t sizes[]= |
| 35 | { 5, 11, 23, 47, 97, 197, 397, 797, 1597, 3203, 6421, 12853, |
| 36 | 25717, 51437, 102877, 205759, 411527, 823117, 1646237, |
| 37 | 3292489, 6584983, 13169977, 26339969, 52679969, 105359939, |
| 38 | 210719881, 421439783, 842879579, 1685759167, 0 }; |
| 39 | static int deleted=0; |
| 40 | static int unallocated=0; |
| 41 | |
| 42 | static int alloc_ht(T_HashTable *H, size_t size) |
| 43 | { |
| 44 | int i; |
| 45 | size_t ii; |
| 46 | |
| 47 | for(i=0; sizes[i]; i++) |
| 48 | if (sizes[i] > size*4 ) |
| 49 | break; |
| 50 | if (!sizes[i]) |
| 51 | for(i=0; sizes[i]; i++) |
| 52 | if (sizes[i] > size*2 ) |
| 53 | break; |
| 54 | if (!sizes[i]) |
| 55 | for(i=0; sizes[i]; i++) |
| 56 | if (sizes[i] > size) |
| 57 | break; |
| 58 | if(!sizes[i]) |
| 59 | return -1; |
| 60 | size = sizes[i]; |
| 61 | if(size < H->size) |
| 62 | size = H->size; /* never shrink the table */ |
| 63 | H->max = size * 4 / 5 - 2; |
| 64 | H->size = size; |
| 65 | H->fill = 0; |
| 66 | H->inuse = 0; |
| 67 | H->entries = NewArray(size, T_HashTableEl); |
| 68 | if (H->entries == NULL) |
| 69 | return -1; /* out of memory error */ |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 70 | |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 71 | for(ii=0; ii < size; ii++) |
| 72 | H->entries[ii] = &unallocated; |
| 73 | return 0; |
| 74 | } |
| 75 | |
| 76 | int make_ht(T_HashFunc f1, T_HashFunc f2, T_ComparFunc c, size_t size, |
| 77 | T_HashTable **H) |
| 78 | { |
| 79 | *H = New(T_HashTable); |
| 80 | if (*H == NULL){ |
| 81 | return -1; /* out of memory error */ |
| 82 | } |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 83 | |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 84 | (*H)->f1 = f1; |
| 85 | (*H)->f2 = f2; |
| 86 | (*H)->compar = c; |
| 87 | (*H)->size = 0; |
| 88 | if(alloc_ht(*H,size)) |
| 89 | return -1; |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | int free_ht(T_HashTable *H, T_HashFunc entry_free) |
| 94 | { |
| 95 | size_t i; |
| 96 | if(entry_free) |
| 97 | for(i=0; i< H->size; i++) |
| 98 | if (H->entries[i] != &unallocated && |
| 99 | H->entries[i] != &deleted) |
| 100 | entry_free(H->entries[i]); |
| 101 | Free(H->entries); |
| 102 | Free(H); |
| 103 | return 0; |
| 104 | } |
| 105 | |
| 106 | /* add into hash table without checking for repeats */ |
| 107 | static int _hash_add(T_HashTable *H,T_HashTableEl *E, size_t *hint) |
| 108 | { |
| 109 | size_t f2, pos; |
| 110 | int ctr; |
| 111 | |
| 112 | pos = H->f1(E) % H->size; |
| 113 | f2 = (size_t) -1; |
| 114 | ctr = 0; |
| 115 | while(H->entries[pos] != &unallocated && |
| 116 | H->entries[pos] != &deleted){ |
| 117 | if (f2 == (size_t) -1) |
| 118 | f2 = H->f2(E) % (H->size - 1); |
| 119 | pos = (pos+f2+1) % H->size; |
| 120 | ctr++; |
| 121 | } |
| 122 | if(H->entries[pos] == &unallocated) |
| 123 | H->fill++; /* only increase fill if the previous element was not yet |
| 124 | * counted, i.e. unallocated */ |
| 125 | H->inuse++; |
| 126 | H->entries[pos] = E; |
| 127 | if(hint) |
| 128 | *hint = pos; |
| 129 | return 0; |
| 130 | } |
| 131 | |
| 132 | static int rehash(T_HashTable *H) |
| 133 | { |
| 134 | size_t size,i; |
| 135 | T_HashTableEl *oldentries; |
| 136 | /* resize the table */ |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 137 | |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 138 | size = H->size; |
| 139 | oldentries = H->entries; |
| 140 | if(alloc_ht(H,((H->inuse+1)*4+H->fill)/5)) |
| 141 | return -1; |
| 142 | |
| 143 | for(i=0; i < size; i++){ |
| 144 | if(oldentries[i] != &unallocated && oldentries[i] != &deleted) |
| 145 | _hash_add(H, oldentries[i], 0); |
| 146 | } |
| 147 | Free(oldentries); |
| 148 | return 0; |
| 149 | } |
| 150 | |
| 151 | int hash_add(T_HashTable *H, T_HashTableEl *E, size_t *hint) |
| 152 | { |
| 153 | if (H->fill >= H->max) |
| 154 | rehash(H); |
| 155 | if (H->fill == H->size) |
| 156 | return -1; /*out of memory error */ |
| 157 | return _hash_add(H,E, hint); |
| 158 | } |
| 159 | |
| 160 | |
| 161 | /* add into hash table without checking for repeats */ |
| 162 | static int _hash_lookup(T_HashTable *H,T_HashTableEl *E, T_HashTableEl **E2, |
| 163 | size_t *hint, int isIdentity) |
| 164 | { |
| 165 | size_t f2, pos, upos, ttl; |
| 166 | |
| 167 | pos = H->f1(E) % H->size; |
| 168 | ttl = H->size; |
| 169 | f2 = (size_t) -1; |
| 170 | upos = (size_t) -1; |
| 171 | while(ttl && |
| 172 | H->entries[pos] != &unallocated && |
| 173 | (H->entries[pos] == &deleted || |
| 174 | ((isIdentity || H->compar(H->entries[pos], E) != 0) && |
| 175 | (!isIdentity || H->entries[pos] != E)))){ |
| 176 | if (f2 == (size_t) -1) |
| 177 | f2 = H->f2(E) % (H->size - 1); |
| 178 | if (upos == (size_t) -1 && H->entries[pos] == &deleted) |
| 179 | upos = pos; |
| 180 | pos = (pos+f2+1) % H->size; |
| 181 | ttl--; |
| 182 | } |
| 183 | if(H->entries[pos] == &unallocated || !ttl) |
| 184 | return -1; |
| 185 | if (upos != (size_t) -1){ |
| 186 | H->entries[upos] = H->entries[pos]; |
| 187 | H->entries[pos] = &deleted; |
| 188 | pos = upos; |
| 189 | } |
| 190 | if(hint) |
| 191 | *hint = pos; |
| 192 | *E2= H->entries[pos]; |
| 193 | return 0; |
| 194 | } |
| 195 | |
| 196 | |
| 197 | int hash_lookup(T_HashTable *H,T_HashTableEl *E, T_HashTableEl **E2, |
| 198 | size_t *hint) |
| 199 | { |
| 200 | return _hash_lookup(H, E, E2, hint, 0); |
| 201 | } |
| 202 | |
| 203 | /* add into hash table without checking for repeats */ |
| 204 | int hash_remove(T_HashTable *H,T_HashTableEl *E, size_t hint) |
| 205 | { |
| 206 | T_HashTableEl *E2; |
| 207 | |
Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 208 | if (hint < H->size && H->entries[hint] == E){ |
Alistair Delva | beaee83 | 2021-02-24 11:27:23 -0800 | [diff] [blame] | 209 | H->inuse--; |
| 210 | H->entries[hint] = &deleted; |
| 211 | return 0; |
| 212 | } |
| 213 | |
| 214 | if(_hash_lookup(H, E, &E2, &hint, 1)) { |
| 215 | fprintf(stderr, "Removing non-existent entry\n"); |
| 216 | exit(1); |
| 217 | } |
| 218 | H->inuse--; |
| 219 | H->entries[hint] = &deleted; |
| 220 | return 0; |
| 221 | } |