Copy hashtable implementation from another project
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bf9677f2ae
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2
Makefile
2
Makefile
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@ -2,7 +2,7 @@ include common.mk
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all: server
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server: $(BUILD_DIR)/server/main.o
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server: $(BUILD_DIR)/server/main.o $(BUILD_DIR)/common/util/hash_table.o
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$(COMPILE_EXE)
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run: server
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@ -0,0 +1,23 @@
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#ifndef COMMON_DEFS_H_
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#define COMMON_DEFS_H_
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <stdbool.h>
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#define lengthof(arr) (sizeof(arr) / sizeof(*arr))
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#define containerof(ptr, contype, membpath) ((contype*)(0 ? (void)(((contype*)NULL)->membpath = *(ptr)) : (void)0, ((char *)(ptr)) - offsetof(contype, membpath)))
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// Assuming child type has a field for the base type
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// So for structs it is usually actual downcast, but for unions it is an upcast
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#define DOWNCAST(contype, basename, ptr) containerof(ptr, contype, as_##basename)
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#define T_ALLOC(count, T) ((T*)calloc((count), sizeof(T)))
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#define HEADER_FN __attribute__((unused)) inline static
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#ifdef DEBUG
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# define DEBUG_PRINT_VALUE(x, fmt) (void) (fprintf(stderr, #x " = " fmt "\n", x), fflush(stderr))
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#else
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# define DEBUG_PRINT_VALUE(...) (void) (0)
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#endif
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#endif /* end of include guard: COMMON_DEFS_H_ */
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@ -0,0 +1,360 @@
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#include <stdlib.h>
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#include "hash_table.h"
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#define FNV_OFFSET_BASIS 0xCBF29CE484222325
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#define FNV_PRIME 0x00000100000001B3
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inline static uint64_t
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fnv_1a(uint8_t *bytes, size_t length)
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{
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uint64_t hash = FNV_OFFSET_BASIS;
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for (size_t i = 0; i < length; ++i) {
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uint8_t b = bytes[i];
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hash ^= b;
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hash *= FNV_PRIME;
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}
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return hash;
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}
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#define NULL_KEY ((HashTableKey){.length = 0, .bytes = NULL, .pre_hash = 0})
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HashTableKey
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hash_table_key_from_bytes(const char *bytes, size_t size)
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{
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if (!bytes) {
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return NULL_KEY;
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}
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HashTableKey key = {
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.length = size,
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.bytes = bytes,
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.pre_hash = fnv_1a((uint8_t*) bytes, size),
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};
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return key;
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}
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HashTableKey
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hash_table_key_copy(const HashTableKey old)
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{
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if (!old.bytes) {
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return NULL_KEY;
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}
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char *new_bytes = malloc(old.length + 1);
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if (!new_bytes) {
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return NULL_KEY;
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}
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memcpy(new_bytes, old.bytes, old.length);
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new_bytes[old.length] = 0;
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return (HashTableKey) {
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.length = old.length,
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.bytes = new_bytes,
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.pre_hash = old.pre_hash,
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};
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}
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void
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hash_table_key_deinit_copied(HashTableKey *key)
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{
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if (key->bytes) {
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free((char*) key->bytes);
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key->bytes = NULL;
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}
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key->length = 0;
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key->pre_hash = 0;
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}
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#define FAMILY_PRIME 0x1FFFFFFFFFFFFFFF
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inline static HashFamilyMember
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family_random_member()
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{
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uint64_t n[2];
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for (int i = 0; i < 2; ++i) {
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n[i] = (uint64_t)((rand() / (double) RAND_MAX) * (FAMILY_PRIME - RAND_MAX) + rand()) % FAMILY_PRIME;
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}
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if (!n[0]) {
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n[0] = 1;
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}
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return (HashFamilyMember) {
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.a = n[0],
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.b = n[1],
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};
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}
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inline static size_t
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family_map(HashFamilyMember member, uint64_t pre_hash)
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{
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if (!member.a)
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++member.a;
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uint64_t hash = (pre_hash * member.a + member.b) % FAMILY_PRIME; // Integer overflows may influence the properties of this family
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return hash;
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}
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bool
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hash_table_key_equals(const HashTableKey lhs, const HashTableKey rhs)
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{
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if (lhs.pre_hash != rhs.pre_hash) {
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return false;
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}
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if (lhs.length != rhs.length) {
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return false;
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}
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if (lhs.bytes == rhs.bytes) {
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return true;
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}
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if (!lhs.bytes || !rhs.bytes) {
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return false;
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}
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size_t length = lhs.length;
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return memcmp(lhs.bytes, rhs.bytes, length) == 0;
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}
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inline static size_t
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initial_position(const HashTableKey key, const HashTableDynamicData * ht)
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{
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uint64_t hash = family_map(ht->family_member, key.pre_hash);
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return hash % ht->capacity;
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}
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inline static size_t
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probe_next(size_t current_index, size_t base_index, size_t iteration, size_t modulo)
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{
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(void) base_index;
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(void) iteration;
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++current_index;
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current_index %= modulo;
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return current_index;
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}
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static HashTableDynamicData
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create_table(size_t capacity, size_t value_size, HashFamilyMember family_member)
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{
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HashTableDynamicData data = {
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.value_array = NULL,
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.capacity = 0,
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.length = 0,
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.key_array = NULL,
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.family_member = family_member,
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.value_size = value_size,
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};
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void *value_array = calloc(capacity, value_size);
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if (!value_array) {
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return data;
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}
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HashTableKeyEntry *key_array = T_ALLOC(capacity, HashTableKeyEntry);
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if (!key_array) {
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free(value_array);
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return data;
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}
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data.value_array = value_array;
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data.capacity = capacity;
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data.key_array = key_array;
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return data;
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}
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void
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hash_table_init_impl(HashTableDynamicData * data, size_t value_size, void (*value_deinit)(void*))
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{
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*data = create_table(5, value_size, family_random_member());
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data->value_deinit = value_deinit;
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}
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void
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hash_table_deinit_impl(HashTableDynamicData * data)
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{
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if (data->key_array && data->value_array && data->length) {
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void (*value_deinit)(void*) = data->value_deinit;
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for (HashTableIndex i = 0; i < (ssize_t) data->capacity; ++i) {
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if (data->key_array[i].key.bytes) {
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if (value_deinit) {
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value_deinit(data->value_array + (data->value_size * (size_t) i));
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}
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hash_table_key_deinit_copied(&data->key_array[i].key);
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}
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}
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}
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if (data->key_array) {
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free(data->key_array);
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data->key_array = NULL;
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}
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if (data->value_array) {
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free(data->value_array);
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data->value_array = NULL;
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}
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data->capacity = 0;
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data->length = 0;
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}
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static void
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hash_table_grow(HashTableDynamicData * old_ht)
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{
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size_t capacity = old_ht->capacity;
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capacity += (capacity >> 1) + 1;
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const size_t value_size = old_ht->value_size;
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HashTableDynamicData new_ht = create_table(capacity, value_size, old_ht->family_member);
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if (!new_ht.key_array) {
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return;
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}
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for (size_t i = 0; i < old_ht->capacity; ++i) {
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if (!old_ht->key_array[i].key.bytes) {
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continue;
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}
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if (hash_table_insert_impl(&new_ht, old_ht->key_array[i].key, old_ht->value_array + (i * value_size)) < 0) {
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hash_table_deinit_impl(&new_ht);
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return;
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}
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}
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new_ht.value_deinit = old_ht->value_deinit;
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old_ht->value_deinit = NULL;
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// TODO avoid duplication-deletion of the keys
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hash_table_deinit_impl(old_ht);
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*old_ht = new_ht;
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}
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static void
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hash_table_change_hash(HashTableDynamicData * old_ht)
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{
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const size_t capacity = old_ht->capacity;
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const size_t value_size = old_ht->value_size;
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HashTableDynamicData new_ht = create_table(capacity, value_size, family_random_member());
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if (!new_ht.key_array) {
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return;
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}
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for (size_t i = 0; i < old_ht->capacity; ++i) {
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if (!old_ht->key_array[i].key.bytes) {
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continue;
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}
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if (hash_table_insert_impl(&new_ht, old_ht->key_array[i].key, old_ht->value_array + (i * value_size)) < 0) {
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hash_table_deinit_impl(&new_ht);
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return;
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}
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}
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new_ht.value_deinit = old_ht->value_deinit;
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old_ht->value_deinit = NULL;
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// TODO avoid duplication-deletion of the keys
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hash_table_deinit_impl(old_ht);
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*old_ht = new_ht;
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}
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HashTableIndex
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hash_table_insert_impl(HashTableDynamicData * ht, const HashTableKey key, const void * value_ptr)
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{
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if (!key.bytes) {
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return -1;
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}
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size_t length = ht->length;
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size_t capacity = ht->capacity;
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if (length + (length >> 1) >= ht->capacity) {
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hash_table_grow(ht);
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capacity = ht->capacity;
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}
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if (length >= capacity) {
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return -1;
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}
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const size_t base_index = initial_position(key, ht);
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size_t current_index = base_index;
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size_t collision_offset = 0;
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bool found = false;
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bool overwrite = false;
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bool pre_hash_collision = false;
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for (; collision_offset < capacity; current_index = probe_next(current_index, base_index, ++collision_offset, capacity)) {
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if (!ht->key_array[current_index].key.bytes) {
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found = true;
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break;
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}
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if (hash_table_key_equals(key, ht->key_array[current_index].key)) {
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overwrite = true;
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found = true;
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break;
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}
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if (!pre_hash_collision) {
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pre_hash_collision = key.pre_hash == ht->key_array[current_index].key.pre_hash;
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}
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}
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if (!found) {
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return -1;
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}
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void *value_target_ptr = ht->value_array + (ht->value_size * current_index);
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if (ht->key_array[base_index].max_collision_offset < collision_offset) {
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ht->key_array[base_index].max_collision_offset = collision_offset;
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}
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if (overwrite) {
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// Deinitialize the old value
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void (*value_deinit)(void*) = ht->value_deinit;
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if (value_deinit) {
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value_deinit(value_target_ptr);
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}
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} else {
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// Make a local copy of the key
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ht->key_array[current_index].key = hash_table_key_copy(key);
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}
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memcpy(value_target_ptr, value_ptr, ht->value_size); // Assign the value
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ht->length = ++length;
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if (!pre_hash_collision && (collision_offset << 1) > capacity + 6) {
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hash_table_change_hash(ht);
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}
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return current_index;
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}
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HashTableIndex
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hash_table_find_impl(const HashTableDynamicData * ht, const HashTableKey key)
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{
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if (!key.bytes) {
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return -1;
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}
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const size_t capacity = ht->capacity;
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const size_t base_index = initial_position(key, ht);
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const size_t max_collision_offset = ht->key_array[base_index].max_collision_offset;
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size_t collision_offset = 0;
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size_t current_index = base_index;
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for (; collision_offset <= max_collision_offset; current_index = probe_next(current_index, base_index, ++collision_offset, capacity)) {
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if (hash_table_key_equals(key, ht->key_array[current_index].key)) {
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return current_index;
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break;
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}
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}
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return -1;
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}
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bool
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hash_table_delete_at_index_impl(HashTableDynamicData * ht, const HashTableIndex index)
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{
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if (!ht) {
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return false;
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}
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if (index < 0 || (size_t) index > ht->capacity) {
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return false;
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}
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HashTableKeyEntry *key_entry_ptr = ht->key_array + index;
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void *value_ptr = ht->value_array + (ht->value_size * index);
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if (!key_entry_ptr->key.bytes) {
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// No entry at index
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return false;
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}
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// TODO find base_index and reduce its max_collision_offset when provably justified
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hash_table_key_deinit_copied(&key_entry_ptr->key);
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ht->length -= 1;
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void (*value_deinit)(void*) = ht->value_deinit;
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if (value_deinit) {
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value_deinit(value_ptr);
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}
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memset(value_ptr, 0, ht->value_size);
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return true;
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}
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@ -0,0 +1,71 @@
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#ifndef COMMON_UTIL_HASH_TABLE_H_
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#define COMMON_UTIL_HASH_TABLE_H_
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#include <string.h>
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#include "common/defs.h"
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#define HASH_TABLE_INTERFACE_FIELDS \
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size_t capacity; \
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size_t length; \
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HashTableKeyEntry *key_array; \
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HashFamilyMember family_member; \
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;
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#define TYPED_HASH_TABLE(T) union { HashTableDynamicData as_HashTableDynamicData; struct { typeof(T) *value_array; HASH_TABLE_INTERFACE_FIELDS; void (*value_deinit)(typeof(T)*); }; }
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typedef ptrdiff_t HashTableIndex; // Invalidated after hashtable modification
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typedef struct {
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size_t length;
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const char *bytes;
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uint64_t pre_hash;
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} HashTableKey;
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typedef struct {
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HashTableKey key;
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size_t max_collision_offset;
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} HashTableKeyEntry;
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typedef struct {
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uint64_t a, b;
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} HashFamilyMember;
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typedef struct {
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void *value_array;
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HASH_TABLE_INTERFACE_FIELDS;
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void (*value_deinit)(void*);
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size_t value_size;
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} HashTableDynamicData;
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HashTableKey hash_table_key_from_bytes(const char *bytes, size_t size);
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HashTableKey hash_table_key_copy(const HashTableKey old);
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void hash_table_key_deinit_copied(HashTableKey *key);
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bool hash_table_key_equals(const HashTableKey lhs, const HashTableKey rhs);
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__attribute__((unused)) inline static HashTableKey
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hash_table_key_from_cstr(const char *s)
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{
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size_t length = strlen(s);
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return hash_table_key_from_bytes(s, length);
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}
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void hash_table_init_impl(HashTableDynamicData * dyndata, size_t value_size, void (*value_deinit)(void*));
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void hash_table_deinit_impl(HashTableDynamicData * dyndata);
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HashTableIndex hash_table_insert_impl(HashTableDynamicData * dyndata, const HashTableKey key, const void * value_ptr);
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HashTableIndex hash_table_find_impl(const HashTableDynamicData * dyndata, const HashTableKey key);
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bool hash_table_delete_at_index_impl(HashTableDynamicData * dyndata, const HashTableIndex index);
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__attribute__((unused)) inline static bool
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hash_table_delete_by_key_impl(HashTableDynamicData * dyndata, const HashTableKey key)
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{
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return hash_table_delete_at_index_impl(dyndata, hash_table_find_impl(dyndata, key));
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}
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#define hash_table_init(ht, value_deinit) hash_table_init_impl(&(ht)->as_HashTableDynamicData, sizeof(*(ht)->value_array), IMPLICIT_CAST(void(void*), void(typeof((ht)->value_array)), value_deinit))
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#define hash_table_deinit(ht) hash_table_deinit_impl(&(ht)->as_HashTableDynamicData)
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#define hash_table_insert(ht, key, value_ptr) hash_table_insert_impl(&(ht)->as_HashTableDynamicData, key, IMPLICIT_CAST(const void, const typeof(*(ht)->value_array), value_ptr))
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#define hash_table_find(ht, key) hash_table_find_impl(&(ht)->as_HashTableDynamicData, key)
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#define hash_table_delete_at_index(ht, index) hash_table_delete_at_index_impl(&(ht)->as_HashTableDynamicData, index)
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#define hash_table_delete_by_key(ht, key) hash_table_delete_by_key_impl(&(ht)->as_HashTableDynamicData, key)
|
||||
|
||||
#endif /* end of include guard: COMMON_UTIL_HASH_TABLE_H_ */
|
||||
|
|
@ -1,6 +1,7 @@
|
|||
#include "main.h"
|
||||
|
||||
#include <stdio.h>
|
||||
#include "common/util/hash_table.h"
|
||||
|
||||
int
|
||||
main(int argc, char **argv)
|
||||
|
|
|
|||
Loading…
Reference in New Issue