/* $NetBSD: ht.c,v 1.1.2.2 2024/02/24 13:07:20 martin Exp $ */ /* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * SPDX-License-Identifier: MPL-2.0 * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #include #include #include #include #include #include #include #include #include typedef struct isc_ht_node isc_ht_node_t; #define ISC_HT_MAGIC ISC_MAGIC('H', 'T', 'a', 'b') #define ISC_HT_VALID(ht) ISC_MAGIC_VALID(ht, ISC_HT_MAGIC) #define HT_NO_BITS 0 #define HT_MIN_BITS 1 #define HT_MAX_BITS 32 #define HT_OVERCOMMIT 3 #define HT_NEXTTABLE(idx) ((idx == 0) ? 1 : 0) #define TRY_NEXTTABLE(idx, ht) (idx == ht->hindex && rehashing_in_progress(ht)) #define GOLDEN_RATIO_32 0x61C88647 #define HASHSIZE(bits) (UINT64_C(1) << (bits)) struct isc_ht_node { void *value; isc_ht_node_t *next; uint32_t hashval; size_t keysize; unsigned char key[]; }; struct isc_ht { unsigned int magic; isc_mem_t *mctx; size_t count; bool case_sensitive; size_t size[2]; uint8_t hashbits[2]; isc_ht_node_t **table[2]; uint8_t hindex; uint32_t hiter; /* rehashing iterator */ }; struct isc_ht_iter { isc_ht_t *ht; size_t i; uint8_t hindex; isc_ht_node_t *cur; }; static isc_ht_node_t * isc__ht_find(const isc_ht_t *ht, const unsigned char *key, const uint32_t keysize, const uint32_t hashval, const uint8_t idx); static void isc__ht_add(isc_ht_t *ht, const unsigned char *key, const uint32_t keysize, const uint32_t hashval, const uint8_t idx, void *value); static isc_result_t isc__ht_delete(isc_ht_t *ht, const unsigned char *key, const uint32_t keysize, const uint32_t hashval, const uint8_t idx); static uint32_t rehash_bits(isc_ht_t *ht, size_t newcount); static void hashtable_new(isc_ht_t *ht, const uint8_t idx, const uint8_t bits); static void hashtable_free(isc_ht_t *ht, const uint8_t idx); static void hashtable_rehash(isc_ht_t *ht, uint32_t newbits); static void hashtable_rehash_one(isc_ht_t *ht); static void maybe_rehash(isc_ht_t *ht, size_t newcount); static isc_result_t isc__ht_iter_next(isc_ht_iter_t *it); static uint8_t maptolower[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff }; static int memcasecmp(const void *vs1, const void *vs2, size_t len) { uint8_t const *s1 = vs1; uint8_t const *s2 = vs2; for (size_t i = 0; i < len; i++) { uint8_t u1 = s1[i]; uint8_t u2 = s2[i]; int U1 = maptolower[u1]; int U2 = maptolower[u2]; int diff = U1 - U2; if (diff) { return diff; } } return 0; } static bool isc__ht_node_match(isc_ht_node_t *node, const uint32_t hashval, const uint8_t *key, uint32_t keysize, bool case_sensitive) { return (node->hashval == hashval && node->keysize == keysize && (case_sensitive ? (memcmp(node->key, key, keysize) == 0) : (memcasecmp(node->key, key, keysize) == 0))); } static uint32_t hash_32(uint32_t val, unsigned int bits) { REQUIRE(bits <= HT_MAX_BITS); /* High bits are more random. */ return (val * GOLDEN_RATIO_32 >> (32 - bits)); } static bool rehashing_in_progress(const isc_ht_t *ht) { return (ht->table[HT_NEXTTABLE(ht->hindex)] != NULL); } static bool hashtable_is_overcommited(isc_ht_t *ht) { return (ht->count >= (ht->size[ht->hindex] * HT_OVERCOMMIT)); } static uint32_t rehash_bits(isc_ht_t *ht, size_t newcount) { uint32_t newbits = ht->hashbits[ht->hindex]; while (newcount >= HASHSIZE(newbits) && newbits <= HT_MAX_BITS) { newbits += 1; } return (newbits); } /* * Rebuild the hashtable to reduce the load factor */ static void hashtable_rehash(isc_ht_t *ht, uint32_t newbits) { uint8_t oldindex = ht->hindex; uint32_t oldbits = ht->hashbits[oldindex]; uint8_t newindex = HT_NEXTTABLE(oldindex); REQUIRE(ht->hashbits[oldindex] >= HT_MIN_BITS); REQUIRE(ht->hashbits[oldindex] <= HT_MAX_BITS); REQUIRE(ht->table[oldindex] != NULL); REQUIRE(newbits <= HT_MAX_BITS); REQUIRE(ht->hashbits[newindex] == HT_NO_BITS); REQUIRE(ht->table[newindex] == NULL); REQUIRE(newbits > oldbits); hashtable_new(ht, newindex, newbits); ht->hindex = newindex; hashtable_rehash_one(ht); } static void hashtable_rehash_one(isc_ht_t *ht) { isc_ht_node_t **newtable = ht->table[ht->hindex]; uint32_t oldsize = ht->size[HT_NEXTTABLE(ht->hindex)]; isc_ht_node_t **oldtable = ht->table[HT_NEXTTABLE(ht->hindex)]; isc_ht_node_t *node = NULL; isc_ht_node_t *nextnode; /* Find first non-empty node */ while (ht->hiter < oldsize && oldtable[ht->hiter] == NULL) { ht->hiter++; } /* Rehashing complete */ if (ht->hiter == oldsize) { hashtable_free(ht, HT_NEXTTABLE(ht->hindex)); ht->hiter = 0; return; } /* Move the first non-empty node from old hashtable to new hashtable */ for (node = oldtable[ht->hiter]; node != NULL; node = nextnode) { uint32_t hash = hash_32(node->hashval, ht->hashbits[ht->hindex]); nextnode = node->next; node->next = newtable[hash]; newtable[hash] = node; } oldtable[ht->hiter] = NULL; ht->hiter++; } static void maybe_rehash(isc_ht_t *ht, size_t newcount) { uint32_t newbits = rehash_bits(ht, newcount); if (ht->hashbits[ht->hindex] < newbits && newbits <= HT_MAX_BITS) { hashtable_rehash(ht, newbits); } } static void hashtable_new(isc_ht_t *ht, const uint8_t idx, const uint8_t bits) { size_t size; REQUIRE(ht->hashbits[idx] == HT_NO_BITS); REQUIRE(ht->table[idx] == NULL); REQUIRE(bits >= HT_MIN_BITS); REQUIRE(bits <= HT_MAX_BITS); ht->hashbits[idx] = bits; ht->size[idx] = HASHSIZE(ht->hashbits[idx]); size = ht->size[idx] * sizeof(isc_ht_node_t *); ht->table[idx] = isc_mem_get(ht->mctx, size); memset(ht->table[idx], 0, size); } static void hashtable_free(isc_ht_t *ht, const uint8_t idx) { size_t size = ht->size[idx] * sizeof(isc_ht_node_t *); for (size_t i = 0; i < ht->size[idx]; i++) { isc_ht_node_t *node = ht->table[idx][i]; while (node != NULL) { isc_ht_node_t *next = node->next; ht->count--; isc_mem_put(ht->mctx, node, sizeof(*node) + node->keysize); node = next; } } isc_mem_put(ht->mctx, ht->table[idx], size); ht->hashbits[idx] = HT_NO_BITS; ht->table[idx] = NULL; } void isc_ht_init(isc_ht_t **htp, isc_mem_t *mctx, uint8_t bits, unsigned int options) { isc_ht_t *ht = NULL; bool case_sensitive = ((options & ISC_HT_CASE_INSENSITIVE) == 0); REQUIRE(htp != NULL && *htp == NULL); REQUIRE(mctx != NULL); REQUIRE(bits >= 1 && bits <= HT_MAX_BITS); ht = isc_mem_get(mctx, sizeof(*ht)); *ht = (isc_ht_t){ .case_sensitive = case_sensitive, }; isc_mem_attach(mctx, &ht->mctx); hashtable_new(ht, 0, bits); ht->magic = ISC_HT_MAGIC; *htp = ht; } void isc_ht_destroy(isc_ht_t **htp) { isc_ht_t *ht; REQUIRE(htp != NULL); REQUIRE(ISC_HT_VALID(*htp)); ht = *htp; *htp = NULL; ht->magic = 0; for (size_t i = 0; i <= 1; i++) { if (ht->table[i] != NULL) { hashtable_free(ht, i); } } INSIST(ht->count == 0); isc_mem_putanddetach(&ht->mctx, ht, sizeof(*ht)); } static void isc__ht_add(isc_ht_t *ht, const unsigned char *key, const uint32_t keysize, const uint32_t hashval, const uint8_t idx, void *value) { isc_ht_node_t *node; uint32_t hash; hash = hash_32(hashval, ht->hashbits[idx]); node = isc_mem_get(ht->mctx, sizeof(*node) + keysize); *node = (isc_ht_node_t){ .keysize = keysize, .hashval = hashval, .next = ht->table[idx][hash], .value = value, }; memmove(node->key, key, keysize); ht->count++; ht->table[idx][hash] = node; } isc_result_t isc_ht_add(isc_ht_t *ht, const unsigned char *key, const uint32_t keysize, void *value) { uint32_t hashval; REQUIRE(ISC_HT_VALID(ht)); REQUIRE(key != NULL && keysize > 0); if (rehashing_in_progress(ht)) { /* Rehash in progress */ hashtable_rehash_one(ht); } else if (hashtable_is_overcommited(ht)) { /* Rehash requested */ maybe_rehash(ht, ht->count); } hashval = isc_hash32(key, keysize, ht->case_sensitive); if (isc__ht_find(ht, key, keysize, hashval, ht->hindex) != NULL) { return (ISC_R_EXISTS); } isc__ht_add(ht, key, keysize, hashval, ht->hindex, value); return (ISC_R_SUCCESS); } static isc_ht_node_t * isc__ht_find(const isc_ht_t *ht, const unsigned char *key, const uint32_t keysize, const uint32_t hashval, const uint8_t idx) { uint32_t hash; uint8_t findex = idx; nexttable: hash = hash_32(hashval, ht->hashbits[findex]); for (isc_ht_node_t *node = ht->table[findex][hash]; node != NULL; node = node->next) { if (isc__ht_node_match(node, hashval, key, keysize, ht->case_sensitive)) { return (node); } } if (TRY_NEXTTABLE(findex, ht)) { /* * Rehashing in progress, check the other table */ findex = HT_NEXTTABLE(findex); goto nexttable; } return (NULL); } isc_result_t isc_ht_find(const isc_ht_t *ht, const unsigned char *key, const uint32_t keysize, void **valuep) { uint32_t hashval; isc_ht_node_t *node; REQUIRE(ISC_HT_VALID(ht)); REQUIRE(key != NULL && keysize > 0); REQUIRE(valuep == NULL || *valuep == NULL); hashval = isc_hash32(key, keysize, ht->case_sensitive); node = isc__ht_find(ht, key, keysize, hashval, ht->hindex); if (node == NULL) { return (ISC_R_NOTFOUND); } if (valuep != NULL) { *valuep = node->value; } return (ISC_R_SUCCESS); } static isc_result_t isc__ht_delete(isc_ht_t *ht, const unsigned char *key, const uint32_t keysize, const uint32_t hashval, const uint8_t idx) { isc_ht_node_t *prev = NULL; uint32_t hash; hash = hash_32(hashval, ht->hashbits[idx]); for (isc_ht_node_t *node = ht->table[idx][hash]; node != NULL; prev = node, node = node->next) { if (isc__ht_node_match(node, hashval, key, keysize, ht->case_sensitive)) { if (prev == NULL) { ht->table[idx][hash] = node->next; } else { prev->next = node->next; } isc_mem_put(ht->mctx, node, sizeof(*node) + node->keysize); ht->count--; return (ISC_R_SUCCESS); } } return (ISC_R_NOTFOUND); } isc_result_t isc_ht_delete(isc_ht_t *ht, const unsigned char *key, const uint32_t keysize) { uint32_t hashval; uint8_t hindex; isc_result_t result; REQUIRE(ISC_HT_VALID(ht)); REQUIRE(key != NULL && keysize > 0); if (rehashing_in_progress(ht)) { /* Rehash in progress */ hashtable_rehash_one(ht); } hindex = ht->hindex; hashval = isc_hash32(key, keysize, ht->case_sensitive); nexttable: result = isc__ht_delete(ht, key, keysize, hashval, hindex); if (result == ISC_R_NOTFOUND && TRY_NEXTTABLE(hindex, ht)) { /* * Rehashing in progress, check the other table */ hindex = HT_NEXTTABLE(hindex); goto nexttable; } return (result); } void isc_ht_iter_create(isc_ht_t *ht, isc_ht_iter_t **itp) { isc_ht_iter_t *it; REQUIRE(ISC_HT_VALID(ht)); REQUIRE(itp != NULL && *itp == NULL); it = isc_mem_get(ht->mctx, sizeof(isc_ht_iter_t)); *it = (isc_ht_iter_t){ .ht = ht, .hindex = ht->hindex, }; *itp = it; } void isc_ht_iter_destroy(isc_ht_iter_t **itp) { isc_ht_iter_t *it; isc_ht_t *ht; REQUIRE(itp != NULL && *itp != NULL); it = *itp; *itp = NULL; ht = it->ht; isc_mem_put(ht->mctx, it, sizeof(*it)); } isc_result_t isc_ht_iter_first(isc_ht_iter_t *it) { isc_ht_t *ht; REQUIRE(it != NULL); ht = it->ht; it->hindex = ht->hindex; it->i = 0; return (isc__ht_iter_next(it)); } static isc_result_t isc__ht_iter_next(isc_ht_iter_t *it) { isc_ht_t *ht = it->ht; while (it->i < ht->size[it->hindex] && ht->table[it->hindex][it->i] == NULL) { it->i++; } if (it->i < ht->size[it->hindex]) { it->cur = ht->table[it->hindex][it->i]; return (ISC_R_SUCCESS); } if (TRY_NEXTTABLE(it->hindex, ht)) { it->hindex = HT_NEXTTABLE(it->hindex); it->i = 0; return (isc__ht_iter_next(it)); } return (ISC_R_NOMORE); } isc_result_t isc_ht_iter_next(isc_ht_iter_t *it) { REQUIRE(it != NULL); REQUIRE(it->cur != NULL); it->cur = it->cur->next; if (it->cur != NULL) { return (ISC_R_SUCCESS); } it->i++; return (isc__ht_iter_next(it)); } isc_result_t isc_ht_iter_delcurrent_next(isc_ht_iter_t *it) { isc_result_t result = ISC_R_SUCCESS; isc_ht_node_t *dnode = NULL; uint8_t dindex; isc_ht_t *ht; isc_result_t dresult; REQUIRE(it != NULL); REQUIRE(it->cur != NULL); ht = it->ht; dnode = it->cur; dindex = it->hindex; result = isc_ht_iter_next(it); dresult = isc__ht_delete(ht, dnode->key, dnode->keysize, dnode->hashval, dindex); INSIST(dresult == ISC_R_SUCCESS); return (result); } void isc_ht_iter_current(isc_ht_iter_t *it, void **valuep) { REQUIRE(it != NULL); REQUIRE(it->cur != NULL); REQUIRE(valuep != NULL && *valuep == NULL); *valuep = it->cur->value; } void isc_ht_iter_currentkey(isc_ht_iter_t *it, unsigned char **key, size_t *keysize) { REQUIRE(it != NULL); REQUIRE(it->cur != NULL); REQUIRE(key != NULL && *key == NULL); *key = it->cur->key; *keysize = it->cur->keysize; } size_t isc_ht_count(const isc_ht_t *ht) { REQUIRE(ISC_HT_VALID(ht)); return (ht->count); }