Util: Dynamically grow hash tables as needed (fixes #1859)

This commit is contained in:
Vicki Pfau 2020-08-17 01:24:37 -07:00
parent a9e0935af8
commit 15fcc90db3
1 changed files with 61 additions and 2 deletions

View File

@ -1,4 +1,4 @@
/* Copyright (c) 2013-2014 Jeffrey Pfau
/* Copyright (c) 2013-2020 Jeffrey Pfau
*
* 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
@ -9,8 +9,9 @@
#include <mgba-util/math.h>
#include <mgba-util/string.h>
#define LIST_INITIAL_SIZE 8
#define LIST_INITIAL_SIZE 4
#define TABLE_INITIAL_SIZE 8
#define REBALANCE_THRESHOLD 4
#define TABLE_COMPARATOR(LIST, INDEX) LIST->list[(INDEX)].key == key
#define HASH_TABLE_STRNCMP_COMPARATOR(LIST, INDEX) LIST->list[(INDEX)].key == hash && strncmp(LIST->list[(INDEX)].stringKey, key, LIST->list[(INDEX)].keylen) == 0
@ -41,6 +42,8 @@ struct TableList {
size_t listSize;
};
void HashTableInsertBinaryMoveKey(struct Table* table, void* key, size_t keylen, void* value);
static inline const struct TableList* _getConstList(const struct Table* table, uint32_t key) {
uint32_t entry = key & (table->tableSize - 1);
return &table->table[entry];
@ -74,6 +77,25 @@ static void _removeItemFromList(struct Table* table, struct TableList* list, siz
}
}
static void _rebalance(struct Table* table) {
struct Table newTable;
TableInit(&newTable, table->tableSize * REBALANCE_THRESHOLD, NULL);
newTable.seed = table->seed * 134775813 + 1;
size_t i;
for (i = 0; i < table->tableSize; ++i) {
const struct TableList* list = &table->table[i];
size_t j;
for (j = 0; j < list->nEntries; ++j) {
HashTableInsertBinaryMoveKey(&newTable, list->list[j].stringKey, list->list[j].keylen, list->list[j].value);
}
free(list->list);
}
free(table->table);
table->tableSize = newTable.tableSize;
table->table = newTable.table;
table->seed = newTable.seed;
}
void TableInit(struct Table* table, size_t initialSize, void (*deinitializer)(void*)) {
if (initialSize < 2) {
initialSize = TABLE_INITIAL_SIZE;
@ -180,6 +202,7 @@ size_t TableSize(const struct Table* table) {
void HashTableInit(struct Table* table, size_t initialSize, void (*deinitializer)(void*)) {
TableInit(table, initialSize, deinitializer);
table->seed = 1;
}
void HashTableDeinit(struct Table* table) {
@ -207,6 +230,11 @@ void* HashTableLookupBinary(const struct Table* table, const void* key, size_t k
void HashTableInsert(struct Table* table, const char* key, void* value) {
uint32_t hash = hash32(key, strlen(key), table->seed);
struct TableList* list = _getList(table, hash);
if (table->size >= table->tableSize * REBALANCE_THRESHOLD) {
_rebalance(table);
hash = hash32(key, strlen(key), table->seed);
list = _getList(table, hash);
}
TABLE_LOOKUP_START(HASH_TABLE_STRNCMP_COMPARATOR, list) {
if (value != lookupResult->value) {
if (table->deinitializer) {
@ -228,6 +256,11 @@ void HashTableInsert(struct Table* table, const char* key, void* value) {
void HashTableInsertBinary(struct Table* table, const void* key, size_t keylen, void* value) {
uint32_t hash = hash32(key, keylen, table->seed);
struct TableList* list = _getList(table, hash);
if (table->size >= table->tableSize * REBALANCE_THRESHOLD) {
_rebalance(table);
hash = hash32(key, keylen, table->seed);
list = _getList(table, hash);
}
TABLE_LOOKUP_START(HASH_TABLE_MEMCMP_COMPARATOR, list) {
if (value != lookupResult->value) {
if (table->deinitializer) {
@ -247,6 +280,32 @@ void HashTableInsertBinary(struct Table* table, const void* key, size_t keylen,
++table->size;
}
void HashTableInsertBinaryMoveKey(struct Table* table, void* key, size_t keylen, void* value) {
uint32_t hash = hash32(key, keylen, table->seed);
struct TableList* list = _getList(table, hash);
if (table->size >= table->tableSize * REBALANCE_THRESHOLD) {
_rebalance(table);
hash = hash32(key, keylen, table->seed);
list = _getList(table, hash);
}
TABLE_LOOKUP_START(HASH_TABLE_MEMCMP_COMPARATOR, list) {
if (value != lookupResult->value) {
if (table->deinitializer) {
table->deinitializer(lookupResult->value);
}
lookupResult->value = value;
}
return;
} TABLE_LOOKUP_END;
list = _resizeAsNeeded(table, list, hash);
list->list[list->nEntries].key = hash;
list->list[list->nEntries].stringKey = key;
list->list[list->nEntries].keylen = keylen;
list->list[list->nEntries].value = value;
++list->nEntries;
++table->size;
}
void HashTableRemove(struct Table* table, const char* key) {
uint32_t hash = hash32(key, strlen(key), table->seed);
struct TableList* list = _getList(table, hash);