1 files changed, 40 insertions, 0 deletions
diff --git a/util/array.c b/util/array.c
new file mode 100644
index 0000000..ec16a7b
--- /dev/null
+++ b/util/array.c
@@ -0,0 +1,40 @@
+#include "util/array.h"
+#include <assert.h>
+#include <string.h>
+
+void array_remove_at(struct wl_array *arr, size_t offset, size_t size) {
+	assert(arr->size >= offset + size);
+
+	char *data = arr->data;
+	memmove(&data[offset], &data[offset + size], arr->size - offset - size);
+	arr->size -= size;
+}
+
+bool array_realloc(struct wl_array *arr, size_t size) {
+	// If the size is less than 1/4th of the allocation size, we shrink it.
+	// 1/4th is picked to provide hysteresis, without which an array with size
+	// arr->alloc would constantly reallocate if an element is added and then
+	// removed continously.
+	size_t alloc;
+	if (arr->alloc > 0 && size > arr->alloc / 4) {
+		alloc = arr->alloc;
+	} else {
+		alloc = 16;
+	}
+
+	while (alloc < size) {
+		alloc *= 2;
+	}
+
+	if (alloc == arr->alloc) {
+		return true;
+	}
+
+	void *data = realloc(arr->data, alloc);
+	if (data == NULL) {
+		return false;
+	}
+	arr->data = data;
+	arr->alloc = alloc;
+	return true;
+}