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Dynamic list in C
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/* | |
* Dynamic List | |
* Reference: https://eddmann.com/posts/implementing-a-dynamic-vector-array-in-c | |
*/ | |
#include <stdlib.h> | |
#define LIST_DEFAULT_CAPACITY 10 | |
typedef struct list { | |
void **items; | |
int size; | |
int capacity; | |
} List; | |
void list_init(List *l) | |
{ | |
l->capacity = LIST_DEFAULT_CAPACITY; | |
l->items = malloc(l->capacity * sizeof(void*)); | |
l->size = 0; | |
} | |
int list_size(List *l) | |
{ | |
return l->size; | |
} | |
static int list_index_valid(List *l, int index) | |
{ | |
return index >= 0 && index < l->size; | |
} | |
static void list_resize(List *l, int capacity) | |
{ | |
void** items = realloc(l->items, capacity * sizeof(void*)); | |
if (items) { | |
l->items = items; | |
l->capacity = capacity; | |
} | |
} | |
void list_add(List *l, void *item) | |
{ | |
// Size check before add | |
if (l->size == l->capacity) { | |
list_resize(l, l->capacity * 2); | |
} | |
l->items[l->size] = item; | |
l->size++; | |
} | |
void* list_get(List *l, int index) | |
{ | |
if (!list_index_valid(l, index)) { | |
return NULL; | |
} | |
return l->items[index]; | |
} | |
void list_set(List *l, int index, void* item) | |
{ | |
if (!list_index_valid(l, index)) { | |
return; | |
} | |
l->items[index] = item; | |
} | |
void list_remove(List *l, int index) | |
{ | |
if (!list_index_valid(l, index)) { | |
return; | |
} | |
l->items[index] = NULL; | |
l->size--; | |
// Relink next items | |
for (int i = index; i < l->size; i++) { | |
l->items[i] = l->items[i+1]; | |
l->items[i+1] = NULL; | |
} | |
// Check if we can downsize list | |
if (l->size == l->capacity / 4) { | |
list_resize(l, l->capacity / 2); | |
} | |
} | |
void list_free(List *l) | |
{ | |
free(l->items); | |
} |
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