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made hashmaps extensibe by packing them in a horrible macro

banana-cakes
FelixBrendel 6 years ago
parent
854593273f
commit
2f6954b520
1 changed files with 159 additions and 169 deletions
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  1. +159
    -169
      hashmap.hpp

+ 159
- 169
hashmap.hpp View File

@@ -4,173 +4,163 @@
#include <stdlib.h> #include <stdlib.h>
#include "types.hpp" #include "types.hpp"


#define for_str_hash_map(hm) \
if (char* key = nullptr); else \
if (void* value = nullptr); else \
for(int i = 0; i < hm->current_capacity; ++i) \
if (!((key = hm->data[i].original_string) && \
(value = hm->data[i].object))); else




struct StringHashMapCell {
char* original_string;
void* object;
u64 hash;
bool deleted;
};

struct StringHashMap {
int current_capacity;
int cell_count;
StringHashMapCell* data;
};

inline void print_hm(StringHashMap* hm) {
for_str_hash_map(hm) {
printf("index: %d key: %s value: %llu\n", i, key, (unsigned long long)value);
}
}

inline bool strings_match(char* a, char* b) {
return strcmp(a, b) == 0;
}

u32 hash(char* str) {
u32 value = str[0] << 7;
int i = 0;
while (str[i]) {
value = (10000003 * value) ^ str[i++];
}
return value ^ i;
}

StringHashMap* create_hashmap(int initial_capacity = 8) {
StringHashMap* hm = new StringHashMap;
hm->current_capacity = initial_capacity;
hm->cell_count = 0;
// set all data to nullptr
hm->data = (StringHashMapCell *)calloc(initial_capacity, sizeof(StringHashMapCell));
// printf("check: %s\n", hm->data[6].original_string);
return hm;
}

int hm_get_index_of_living_cell_if_it_exists(StringHashMap* hm, char* key, u64 hash_val) {
int index = hash_val % hm->current_capacity;
StringHashMapCell cell = hm->data[index];
// test if cell exists at that index
if (cell.original_string) {
// check if strings match
if (strings_match(key, cell.original_string)) {
// we found it, now check it it is deleted:
if (cell.deleted) {
// we found it but it was deleted, we dont have to
// check for collisions then
return -1;
} else {
// we found it and it is not deleted
return index;
}
} else {
// strings dont match, this means we have a collision.
// We just search front to back, lol
for (int i = 0; i < hm->current_capacity; ++i) {
cell = hm->data[i];
if (!cell.original_string)
continue;
if (!strings_match(key, cell.original_string))
continue;
if (cell.deleted)
continue;
return i;
}
// not or only deleted cells found
return -1;
}
} else {
// no cell exists at this index so the item was never in the
// hashmap. Either it would be there or be ther and 'deleted'
// or another item would be there and therefore a collistion
// would exist
return -1;
}
}

inline bool hm_key_exists(StringHashMap* hm, char* key) {
return hm_get_index_of_living_cell_if_it_exists(hm, key, hash(key)) != -1;
}

inline void* hm_get_object(StringHashMap* hm, char* key) {
int index = hm_get_index_of_living_cell_if_it_exists(hm, key, hash(key));
if (index != -1) {
return hm->data[index].object;
}
return nullptr;
}

inline void hm_delete_object(StringHashMap* hm, char* key) {
int index = hm_get_index_of_living_cell_if_it_exists(hm, key, hash(key));
if (index != -1) {
hm->data[index].deleted = true;
}
}

void hm_set(StringHashMap* hm, char* key, void* obj) {
u64 hash_val = hash(key);
int index = hash_val % hm->current_capacity;

// if we the desired cell is just empty, write to it and done :)
if (!hm->data[index].original_string) {
// insert new cell into desired slot
++hm->cell_count;
} else {
if (strings_match(key, hm->data[index].original_string)) {
// overwrite object with same key, dont increment cell
// count
} else {
// collision, check resize
++hm->cell_count;
if ((hm->cell_count*1.0f / hm->current_capacity) > 0.666f) {
StringHashMapCell* old_data = hm->data;
hm->data = (StringHashMapCell*)calloc(hm->current_capacity*4, sizeof(StringHashMapCell));
hm->cell_count = 0;
hm->current_capacity *= 4;

// insert all old items again
for (int i = 0; i < hm->current_capacity/4; ++i) {
StringHashMapCell cell = old_data[i];
if (cell.original_string) {
hm_set(hm, cell.original_string, cell.object);
}
}
free(old_data);
index = hash_val % hm->current_capacity;
}
// search for empty slot for new cell starting at desired index;
// preventing gotos using lambdas!
[&](){
for (int i = index; i < hm->current_capacity; ++i) {
if (!hm->data[i].original_string ||
strings_match(hm->data[i].original_string, key))
{
index = i;
return;
}
}
for (int i = 0; i < index; ++i) {
if (!hm->data[i].original_string ||
strings_match(hm->data[i].original_string, key))
{
index = i;
return;
}
}
}();
}
}

hm->data[index].deleted = false;
hm->data[index].original_string = key;
hm->data[index].hash = hash_val;
hm->data[index].object = obj;
}
// inline void print_hm(StringHashMap* hm) {
// for_str_hash_map(hm) {
// printf("index: %d desired-index: %llu key: %s hash: %llu value: %llu\n", i, (hm->data[i].hash % hm->current_capacity), (char*)key, hm->data[i].hash, (unsigned long long)value);
// }
// }

#define __for_hm_generator(key_type, hm) \
if (key_type key = nullptr); else \
if (void* value = nullptr); else \
for(int index = 0; index < hm->current_capacity; ++index) \
if (!((key = hm->data[index].original) && \
(value = hm->data[index].object))); else


#define define_hash_map(type, name) \
\
struct name##_Hash_Map_Cell { \
type original; \
u64 hash; \
bool deleted; \
void* object; \
}; \
\
struct name##_Hash_Map { \
int current_capacity; \
int cell_count; \
name##_Hash_Map_Cell* data; \
}; \
\
name##_Hash_Map* create_##name##_hashmap(int initial_capacity=8) { \
name##_Hash_Map* hm = new name##_Hash_Map; \
hm->current_capacity = initial_capacity; \
hm->cell_count = 0; \
/* set all data to nullptr */ \
hm->data = (name##_Hash_Map_Cell*)calloc(initial_capacity, sizeof(name##_Hash_Map_Cell)); \
/* printf("check: %s\n", hm->data[6].original_string); */ \
return hm; \
} \
\
int hm_get_index_of_living_cell_if_it_exists(name##_Hash_Map* hm, type key, u64 hash_val) { \
int index = hash_val % hm->current_capacity; \
name##_Hash_Map_Cell cell = hm->data[index]; \
/* test if cell exists at that index */ \
if (cell.original) { \
/* check if strings match */ \
if (hm_objects_match(key, cell.original)) { \
/* we found it, now check it it is deleted: */ \
if (cell.deleted) { \
/* we found it but it was deleted, we */ \
/* dont have to check for collisions then */ \
return -1; \
} else { \
/* we found it and it is not deleted */ \
return index; \
} \
} else { \
/* strings dont match, this means we have */ \
/* a collision. We just search forward */ \
for (int i = 0; i < hm->current_capacity; ++i) { \
int new_idx = (i + index) % hm->current_capacity; \
cell = hm->data[new_idx]; \
if (!cell.original) \
return -1; \
if (!hm_objects_match(key, cell.original)) \
continue; \
if (cell.deleted) \
continue; \
return new_idx; \
} \
/* not or only deleted cells found */ \
return -1; \
} \
} else { \
/* no cell exists at this index so the item was never in the */ \
/* hashmap. Either it would be there or be ther and 'deleted' */ \
/* or another item would be there and therefore a collistion */ \
/* would exist */ \
return -1; \
} \
} \
\
inline bool hm_key_exists(name##_Hash_Map* hm, type key) { \
return hm_get_index_of_living_cell_if_it_exists(hm, key, hm_hash(key)) != -1; \
} \
\
inline void* hm_get_object(name##_Hash_Map* hm, type key) { \
int index = hm_get_index_of_living_cell_if_it_exists(hm, key, hm_hash(key)); \
if (index != -1) { \
return hm->data[index].object; \
} \
return nullptr; \
} \
\
inline void hm_delete_object(name##_Hash_Map* hm, char* key) { \
int index = hm_get_index_of_living_cell_if_it_exists(hm, key, hm_hash(key)); \
if (index != -1) { \
hm->data[index].deleted = true; \
} \
} \
\
void hm_set(name##_Hash_Map* hm, type key, void* obj) { \
u64 hash_val = hm_hash(key); \
int index = hash_val % hm->current_capacity; \
\
/* if we the desired cell is just empty, write to it and done :) */ \
if (!hm->data[index].original) { \
/* insert new cell into desired slot */ \
++hm->cell_count; \
} else { \
if (hm_objects_match(key, hm->data[index].original)) { \
/* overwrite object with same key, dont increment cell */ \
/* count */ \
} else { \
/* collision, check resize */ \
++hm->cell_count; \
if ((hm->cell_count*1.0f / hm->current_capacity) > 0.666f) { \
auto old_data = hm->data; \
hm->data = (name##_Hash_Map_Cell*)calloc(hm->current_capacity*4, sizeof(name##_Hash_Map_Cell)); \
hm->cell_count = 0; \
hm->current_capacity *= 4; \
\
/* insert all old items again */ \
for (int i = 0; i < hm->current_capacity/4; ++i) { \
auto cell = old_data[i]; \
if (cell.original) { \
hm_set(hm, cell.original, cell.object); \
} \
} \
free(old_data); \
index = hash_val % hm->current_capacity; \
} \
/* search for empty slot for new cell starting at desired index; */ \
/* preventing gotos using lambdas! */ \
[&](){ \
for (int i = index; i < hm->current_capacity; ++i) { \
if (!hm->data[i].original || \
hm_objects_match(hm->data[i].original, key)) \
{ \
index = i; \
return; \
} \
} \
for (int i = 0; i < index; ++i) { \
if (!hm->data[i].original || \
hm_objects_match(hm->data[i].original, key)) \
{ \
index = i; \
return; \
} \
} \
}(); \
} \
} \
\
hm->data[index].deleted = false; \
hm->data[index].original = key; \
hm->data[index].hash = hash_val; \
hm->data[index].object = obj; \
} \

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