ref: d9c1b669314842eab152392263db8ab77c1b257f
dir: /src/hashmap.c/
/* * This file is part of RGBDS. * * Copyright (c) 2019, Eldred Habert and RGBDS contributors. * * SPDX-License-Identifier: MIT */ #include <stdint.h> #include <stdbool.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include "hashmap.h" #include "extern/err.h" /* * The lower half of the hash is used to index the "master" table, * the upper half is used to help resolve collisions more quickly */ #define UINT_BITS_(NB_BITS) uint##NB_BITS##_t #define UINT_BITS(NB_BITS) UINT_BITS_(NB_BITS) typedef UINT_BITS(HASH_NB_BITS) HashType; typedef UINT_BITS(HALF_HASH_NB_BITS) HalfHashType; struct HashMapEntry { HalfHashType hash; char const *key; void *content; struct HashMapEntry *next; }; #define FNV_OFFSET_BASIS 0x811c9dc5 #define FNV_PRIME 16777619 /* FNV-1a hash */ static HashType hash(char const *str) { HashType hash = FNV_OFFSET_BASIS; while (*str) { hash ^= (uint8_t)*str++; hash *= FNV_PRIME; } return hash; } bool hash_AddElement(HashMap map, char const *key, void *element) { HashType hashedKey = hash(key); HalfHashType index = hashedKey; struct HashMapEntry *newEntry = malloc(sizeof(*newEntry)); if (!newEntry) err(1, "%s: Failed to allocate new entry", __func__); newEntry->hash = hashedKey >> HALF_HASH_NB_BITS; newEntry->key = key; newEntry->content = element; newEntry->next = map[index]; map[index] = newEntry; return newEntry->next != NULL; } bool hash_DeleteElement(HashMap map, char const *key) { HashType hashedKey = hash(key); struct HashMapEntry **ptr = &map[(HalfHashType)hashedKey]; while (*ptr) { if (hashedKey >> HALF_HASH_NB_BITS == (*ptr)->hash && !strcmp((*ptr)->key, key)) { struct HashMapEntry *next = (*ptr)->next; free(*ptr); *ptr = next; return true; } } return false; } void *hash_GetElement(HashMap const map, char const *key) { HashType hashedKey = hash(key); struct HashMapEntry *ptr = map[(HalfHashType)hashedKey]; while (ptr) { if (hashedKey >> HALF_HASH_NB_BITS == ptr->hash && !strcmp(ptr->key, key)) { return ptr->content; } ptr = ptr->next; } return NULL; } void hash_ForEach(HashMap const map, void (*func)(void *, void *), void *arg) { for (size_t i = 0; i < HASHMAP_NB_BUCKETS; i++) { struct HashMapEntry *ptr = map[i]; while (ptr) { func(ptr->content, arg); ptr = ptr->next; } } } void hash_EmptyMap(HashMap map) { for (size_t i = 0; i < HASHMAP_NB_BUCKETS; i++) { struct HashMapEntry *ptr = map[i]; while (ptr) { struct HashMapEntry *next = ptr->next; free(ptr); ptr = next; } map[i] = NULL; } }