refactor

remove the free function entirely. all allocators are now expected to
implement reset instead. I reallized I never ever want to free an
individual allocation ever again. The forever_allocator is a special
case wherEreset is a no-op. The arena allocator was deleted. It will be
replaced soon.

test_buffer_allocator.c

@@ -2,7 +2,7 @@
 #include "cig.h"
 
 static void test_buffer_alloc(buffer_allocator_t impl) {
-    allocator_t inter = buffer_allocator_interface(&impl);
+    allocator_t inter = buffer_allocator(&impl);
     const int n_ints = 100;
     int *ints = allocator_alloc(inter, sizeof(int) * n_ints);
     for (int i = 0; i < n_ints; i++) {
@@ -20,15 +20,10 @@ static void test_buffer_alloc(buffer_allocator_t impl) {
         cr_assert_eq(ints[i], i);
     }
     cr_assert_eq(impl.size, sizeof(int)*2*n_ints);
-    allocator_free(inter, ints);
-    size_t remaining_bytes = impl.capacity - impl.size;
-    size_t double_remaining_bytes = 2 * remaining_bytes;
-    void *should_be_null = allocator_resize(inter, ints, double_remaining_bytes);
-    cr_assert_eq(should_be_null, NULL);
     size_t double_ints = ((size_t) n_ints) * 2;
     void *should_be_addr = allocator_resize(inter, ints, double_ints);
     cr_assert_neq(should_be_addr, NULL);
-    buffer_allocator_reset(&impl);
+    allocator_reset(inter);
 }
 
 Test(buffer_allocator, test) {