.

darr.h

@@ -0,0 +1,82 @@
+#ifndef COLLA_DARR_HEADER
+#define COLLA_DARR_HEADER
+
+/*
+dynamic chunked array which uses an arena to allocate,
+the structure needs to follow this exact format, if you want
+you can use the macro darr_define(struct_name, item_type) instead:
+
+////////////////////////////////////
+
+typedef struct arr_t arr_t;
+struct arr_t {
+    int *items;
+    usize block_size;
+    usize count;
+    arr_t *next;
+    arr_t *head;
+};
+// equivalent to
+
+darr_define(arr_t, int);
+
+////////////////////////////////////
+
+by default a chunk is 64 items long, you can change this default
+by modifying the arr.block_size value before adding to the array,
+or by defining DARRAY_DEFAULT_BLOCK_SIZE
+
+usage example:
+
+////////////////////////////////////
+
+darr_define(arr_t, int);
+
+arr_t *arr = NULL;
+
+for (int i = 0; i < 100; ++i) {
+    darr_push(&arena, arr, i);
+}
+
+for_each (chunk, arr) {
+    for (int i = 0; i < chunk->count; ++i) {
+        info("%d -> %d", i, chunk->items[i]);
+    }
+}
+*/
+
+#define DARRAY_DEFAULT_BLOCK_SIZE (64)
+
+#define darr_define(struct_name, item_type) typedef struct struct_name struct_name; \
+    struct struct_name { \
+        item_type *items; \
+        usize block_size; \
+        usize count; \
+        struct_name *next; \
+        struct_name *head; \
+    }
+
+#define darr__alloc_first(arena, arr) do { \
+        (arr) = (arr) ? (arr) : alloc(arena, typeof(*arr)); \
+        (arr)->head = (arr)->head ? (arr)->head : (arr); \
+        (arr)->block_size = (arr)->block_size ? (arr)->block_size : DARRAY_DEFAULT_BLOCK_SIZE; \
+        (arr)->items = alloc(arena, typeof(*arr->items), arr->block_size); \
+        assert((arr)->count == 0); \
+    } while (0)
+
+#define darr__alloc_block(arena, arr) do { \
+        typeof(arr) newarr = alloc(arena, typeof(*arr)); \
+        newarr->block_size = arr->block_size; \
+        newarr->items = alloc(arena, typeof(*arr->items), arr->block_size); \
+        newarr->head = arr->head; \
+        arr->next = newarr; \
+        arr = newarr; \
+    } while (0)
+
+#define darr_push(arena, arr, item) do { \
+        if (!(arr) || (arr)->items == NULL) darr__alloc_first(arena, arr); \
+        if ((arr)->count >= (arr)->block_size) darr__alloc_block(arena, arr); \
+        (arr)->items[(arr)->count++] = (item); \
+    } while (0)
+
+#endif