slak44 / c-arraylist

c-arraylist

A simple C11 array list implementation. Automatically resizable, provides bounds checking.

API

Action	Complexity	Function/Macro
indexing	O(1)	alist_at
front	O(1)	alist_front
push	O(1), amortized	alist_push
pop front	O(1)	alist_pop_front/alist_remove (at index 0)
pop back	O(1)	alist_remove (at last index)
remove	O(n)	alist_remove/alist_remove_item
search	O(n)	ALIST_FIND

Other functions:

• alist_create: create an array list
• alist_free: free an existing array list
• alist_shrink: frees allocated but unused memory
• alist_clear: marks all elements removed, but does not free memory

Useful macros:

• ALIST_FOR_EACH(type, item, list) body: iterate all values
• ALIST_FIND(type, item, list, condition): find first value matching condition, or null

Usage

To use, simply include array_list.h and compile array_list.c.

Example:

#include <array_list.h>
#include <stdio.h>

int main() {
  struct array_list list = alist_create(sizeof(int), 5);
  alist_push(&list, &(int) {1});
  alist_push(&list, &(int) {2});
  alist_push(&list, &(int) {3});
  alist_push(&list, &(int) {4});
  alist_push(&list, &(int) {5});
  alist_push(&list, &(int) {6});
  printf("size is %d, capacity is %d\n", list.size, list.capacity);

  alist_remove(&list, 1);
  printf("size is %d, capacity is %d\n", list.size, list.capacity);

  alist_shrink(&list);
  printf("size is %d, capacity is %d\n", list.size, list.capacity);

  int* second = alist_at(&list, 1);
  printf("second item is %d\n", *second);

  ALIST_FOR_EACH(int, value, &list) {
    printf("%d\n", *value);
    if (*value == 5) break;
  }

  ALIST_FIND(int, needle, &list, *needle > 4 && *needle % 2 == 0);
  printf("needle is %d\n", *needle);

  ALIST_FIND(int, big_number, &list, *big_number > 10000);
  printf("was big number found?: %s\n", big_number != NULL ? "yes" : "no");

  alist_free(&list);
  return 0;
}

Tests

A bunch of tests can be found in tests/array_list_test.c.