diff -r 22257f6d06a3 -r bc782cca0759 ucx/array_list.c
--- a/ucx/array_list.c	Thu May 23 23:19:06 2024 +0200
+++ b/ucx/array_list.c	Thu May 23 23:23:36 2024 +0200
@@ -27,12 +27,30 @@
  */
 
 #include "cx/array_list.h"
+#include "cx/compare.h"
 #include <assert.h>
 #include <string.h>
 
+// Default array reallocator
+
+static void *cx_array_default_realloc(
+        void *array,
+        size_t capacity,
+        size_t elem_size,
+        __attribute__((__unused__)) struct cx_array_reallocator_s *alloc
+) {
+    return realloc(array, capacity * elem_size);
+}
+
+struct cx_array_reallocator_s cx_array_default_reallocator_impl = {
+        cx_array_default_realloc, NULL, NULL, 0, 0
+};
+
+struct cx_array_reallocator_s *cx_array_default_reallocator = &cx_array_default_reallocator_impl;
+
 // LOW LEVEL ARRAY LIST FUNCTIONS
 
-enum cx_array_copy_result cx_array_copy(
+enum cx_array_result cx_array_copy(
         void **target,
         size_t *size,
         size_t *capacity,
@@ -59,7 +77,7 @@
     if (needrealloc) {
         // a reallocator and a capacity variable must be available
         if (reallocator == NULL || capacity == NULL) {
-            return CX_ARRAY_COPY_REALLOC_NOT_SUPPORTED;
+            return CX_ARRAY_REALLOC_NOT_SUPPORTED;
         }
 
         // check, if we need to repair the src pointer
@@ -77,7 +95,7 @@
                 *target, cap, elem_size, reallocator
         );
         if (newmem == NULL) {
-            return CX_ARRAY_COPY_REALLOC_FAILED;
+            return CX_ARRAY_REALLOC_FAILED;
         }
 
         // repair src pointer, if necessary
@@ -99,12 +117,13 @@
     *size = newsize;
 
     // return successfully
-    return CX_ARRAY_COPY_SUCCESS;
+    return CX_ARRAY_SUCCESS;
 }
 
 #ifndef CX_ARRAY_SWAP_SBO_SIZE
 #define CX_ARRAY_SWAP_SBO_SIZE 128
 #endif
+unsigned cx_array_swap_sbo_size = CX_ARRAY_SWAP_SBO_SIZE;
 
 void cx_array_swap(
         void *arr,
@@ -172,21 +191,21 @@
 
     char *ptr = arl->data;
 
-    if (list->simple_destructor) {
-        for (size_t i = 0; i < list->size; i++) {
+    if (list->collection.simple_destructor) {
+        for (size_t i = 0; i < list->collection.size; i++) {
             cx_invoke_simple_destructor(list, ptr);
-            ptr += list->item_size;
+            ptr += list->collection.elem_size;
         }
     }
-    if (list->advanced_destructor) {
-        for (size_t i = 0; i < list->size; i++) {
+    if (list->collection.advanced_destructor) {
+        for (size_t i = 0; i < list->collection.size; i++) {
             cx_invoke_advanced_destructor(list, ptr);
-            ptr += list->item_size;
+            ptr += list->collection.elem_size;
         }
     }
 
-    cxFree(list->allocator, arl->data);
-    cxFree(list->allocator, list);
+    cxFree(list->collection.allocator, arl->data);
+    cxFree(list->collection.allocator, list);
 }
 
 static size_t cx_arl_insert_array(
@@ -196,25 +215,25 @@
         size_t n
 ) {
     // out of bounds and special case check
-    if (index > list->size || n == 0) return 0;
+    if (index > list->collection.size || n == 0) return 0;
 
     // get a correctly typed pointer to the list
     cx_array_list *arl = (cx_array_list *) list;
 
     // do we need to move some elements?
-    if (index < list->size) {
+    if (index < list->collection.size) {
         char const *first_to_move = (char const *) arl->data;
-        first_to_move += index * list->item_size;
-        size_t elems_to_move = list->size - index;
+        first_to_move += index * list->collection.elem_size;
+        size_t elems_to_move = list->collection.size - index;
         size_t start_of_moved = index + n;
 
-        if (CX_ARRAY_COPY_SUCCESS != cx_array_copy(
+        if (CX_ARRAY_SUCCESS != cx_array_copy(
                 &arl->data,
-                &list->size,
+                &list->collection.size,
                 &arl->capacity,
                 start_of_moved,
                 first_to_move,
-                list->item_size,
+                list->collection.elem_size,
                 elems_to_move,
                 &arl->reallocator
         )) {
@@ -228,13 +247,13 @@
     // therefore, it is impossible to leave this function with an invalid array
 
     // place the new elements
-    if (CX_ARRAY_COPY_SUCCESS == cx_array_copy(
+    if (CX_ARRAY_SUCCESS == cx_array_copy(
             &arl->data,
-            &list->size,
+            &list->collection.size,
             &arl->capacity,
             index,
             array,
-            list->item_size,
+            list->collection.elem_size,
             n,
             &arl->reallocator
     )) {
@@ -254,12 +273,12 @@
 }
 
 static int cx_arl_insert_iter(
-        struct cx_mut_iterator_s *iter,
+        struct cx_iterator_s *iter,
         void const *elem,
         int prepend
 ) {
-    struct cx_list_s *list = iter->src_handle;
-    if (iter->index < list->size) {
+    struct cx_list_s *list = iter->src_handle.m;
+    if (iter->index < list->collection.size) {
         int result = cx_arl_insert_element(
                 list,
                 iter->index + 1 - prepend,
@@ -267,12 +286,12 @@
         );
         if (result == 0 && prepend != 0) {
             iter->index++;
-            iter->elem_handle = ((char *) iter->elem_handle) + list->item_size;
+            iter->elem_handle = ((char *) iter->elem_handle) + list->collection.elem_size;
         }
         return result;
     } else {
-        int result = cx_arl_insert_element(list, list->size, elem);
-        iter->index = list->size;
+        int result = cx_arl_insert_element(list, list->collection.size, elem);
+        iter->index = list->collection.size;
         return result;
     }
 }
@@ -284,58 +303,61 @@
     cx_array_list *arl = (cx_array_list *) list;
 
     // out-of-bounds check
-    if (index >= list->size) {
+    if (index >= list->collection.size) {
         return 1;
     }
 
     // content destruction
-    cx_invoke_destructor(list, ((char *) arl->data) + index * list->item_size);
+    cx_invoke_destructor(list, ((char *) arl->data) + index * list->collection.elem_size);
 
     // short-circuit removal of last element
-    if (index == list->size - 1) {
-        list->size--;
+    if (index == list->collection.size - 1) {
+        list->collection.size--;
         return 0;
     }
 
     // just move the elements starting at index to the left
     int result = cx_array_copy(
             &arl->data,
-            &list->size,
+            &list->collection.size,
             &arl->capacity,
             index,
-            ((char *) arl->data) + (index + 1) * list->item_size,
-            list->item_size,
-            list->size - index - 1,
+            ((char *) arl->data) + (index + 1) * list->collection.elem_size,
+            list->collection.elem_size,
+            list->collection.size - index - 1,
             &arl->reallocator
     );
-    if (result == 0) {
-        // decrease the size
-        list->size--;
-    }
-    return result;
+
+    // cx_array_copy cannot fail, array cannot grow
+    assert(result == 0);
+
+    // decrease the size
+    list->collection.size--;
+
+    return 0;
 }
 
 static void cx_arl_clear(struct cx_list_s *list) {
-    if (list->size == 0) return;
+    if (list->collection.size == 0) return;
 
     cx_array_list *arl = (cx_array_list *) list;
     char *ptr = arl->data;
 
-    if (list->simple_destructor) {
-        for (size_t i = 0; i < list->size; i++) {
+    if (list->collection.simple_destructor) {
+        for (size_t i = 0; i < list->collection.size; i++) {
             cx_invoke_simple_destructor(list, ptr);
-            ptr += list->item_size;
+            ptr += list->collection.elem_size;
         }
     }
-    if (list->advanced_destructor) {
-        for (size_t i = 0; i < list->size; i++) {
+    if (list->collection.advanced_destructor) {
+        for (size_t i = 0; i < list->collection.size; i++) {
             cx_invoke_advanced_destructor(list, ptr);
-            ptr += list->item_size;
+            ptr += list->collection.elem_size;
         }
     }
 
-    memset(arl->data, 0, list->size * list->item_size);
-    list->size = 0;
+    memset(arl->data, 0, list->collection.size * list->collection.elem_size);
+    list->collection.size = 0;
 }
 
 static int cx_arl_swap(
@@ -343,9 +365,9 @@
         size_t i,
         size_t j
 ) {
-    if (i >= list->size || j >= list->size) return 1;
+    if (i >= list->collection.size || j >= list->collection.size) return 1;
     cx_array_list *arl = (cx_array_list *) list;
-    cx_array_swap(arl->data, list->item_size, i, j);
+    cx_array_swap(arl->data, list->collection.elem_size, i, j);
     return 0;
 }
 
@@ -353,39 +375,48 @@
         struct cx_list_s const *list,
         size_t index
 ) {
-    if (index < list->size) {
+    if (index < list->collection.size) {
         cx_array_list const *arl = (cx_array_list const *) list;
         char *space = arl->data;
-        return space + index * list->item_size;
+        return space + index * list->collection.elem_size;
     } else {
         return NULL;
     }
 }
 
-static ssize_t cx_arl_find(
-        struct cx_list_s const *list,
-        void const *elem
+static ssize_t cx_arl_find_remove(
+        struct cx_list_s *list,
+        void const *elem,
+        bool remove
 ) {
-    assert(list->cmpfunc != NULL);
-    assert(list->size < SIZE_MAX / 2);
+    assert(list->collection.cmpfunc != NULL);
+    assert(list->collection.size < SIZE_MAX / 2);
     char *cur = ((cx_array_list const *) list)->data;
 
-    for (ssize_t i = 0; i < (ssize_t) list->size; i++) {
-        if (0 == list->cmpfunc(elem, cur)) {
-            return i;
+    for (ssize_t i = 0; i < (ssize_t) list->collection.size; i++) {
+        if (0 == list->collection.cmpfunc(elem, cur)) {
+            if (remove) {
+                if (0 == cx_arl_remove(list, i)) {
+                    return i;
+                } else {
+                    return -1;
+                }
+            } else {
+                return i;
+            }
         }
-        cur += list->item_size;
+        cur += list->collection.elem_size;
     }
 
     return -1;
 }
 
 static void cx_arl_sort(struct cx_list_s *list) {
-    assert(list->cmpfunc != NULL);
+    assert(list->collection.cmpfunc != NULL);
     qsort(((cx_array_list *) list)->data,
-          list->size,
-          list->item_size,
-          list->cmpfunc
+          list->collection.size,
+          list->collection.elem_size,
+          list->collection.cmpfunc
     );
 }
 
@@ -393,37 +424,37 @@
         struct cx_list_s const *list,
         struct cx_list_s const *other
 ) {
-    assert(list->cmpfunc != NULL);
-    if (list->size == other->size) {
+    assert(list->collection.cmpfunc != NULL);
+    if (list->collection.size == other->collection.size) {
         char const *left = ((cx_array_list const *) list)->data;
         char const *right = ((cx_array_list const *) other)->data;
-        for (size_t i = 0; i < list->size; i++) {
-            int d = list->cmpfunc(left, right);
+        for (size_t i = 0; i < list->collection.size; i++) {
+            int d = list->collection.cmpfunc(left, right);
             if (d != 0) {
                 return d;
             }
-            left += list->item_size;
-            right += other->item_size;
+            left += list->collection.elem_size;
+            right += other->collection.elem_size;
         }
         return 0;
     } else {
-        return list->size < other->size ? -1 : 1;
+        return list->collection.size < other->collection.size ? -1 : 1;
     }
 }
 
 static void cx_arl_reverse(struct cx_list_s *list) {
-    if (list->size < 2) return;
+    if (list->collection.size < 2) return;
     void *data = ((cx_array_list const *) list)->data;
-    size_t half = list->size / 2;
+    size_t half = list->collection.size / 2;
     for (size_t i = 0; i < half; i++) {
-        cx_array_swap(data, list->item_size, i, list->size - 1 - i);
+        cx_array_swap(data, list->collection.elem_size, i, list->collection.size - 1 - i);
     }
 }
 
 static bool cx_arl_iter_valid(void const *it) {
     struct cx_iterator_s const *iter = it;
-    struct cx_list_s const *list = iter->src_handle;
-    return iter->index < list->size;
+    struct cx_list_s const *list = iter->src_handle.c;
+    return iter->index < list->collection.size;
 }
 
 static void *cx_arl_iter_current(void const *it) {
@@ -432,44 +463,32 @@
 }
 
 static void cx_arl_iter_next(void *it) {
-    struct cx_iterator_base_s *itbase = it;
-    if (itbase->remove) {
-        struct cx_mut_iterator_s *iter = it;
-        itbase->remove = false;
-        cx_arl_remove(iter->src_handle, iter->index);
+    struct cx_iterator_s *iter = it;
+    if (iter->base.remove) {
+        iter->base.remove = false;
+        cx_arl_remove(iter->src_handle.m, iter->index);
     } else {
-        struct cx_iterator_s *iter = it;
         iter->index++;
         iter->elem_handle =
                 ((char *) iter->elem_handle)
-                + ((struct cx_list_s const *) iter->src_handle)->item_size;
+                + ((struct cx_list_s const *) iter->src_handle.c)->collection.elem_size;
     }
 }
 
 static void cx_arl_iter_prev(void *it) {
-    struct cx_iterator_base_s *itbase = it;
-    struct cx_mut_iterator_s *iter = it;
-    cx_array_list *const list = iter->src_handle;
-    if (itbase->remove) {
-        itbase->remove = false;
-        cx_arl_remove(iter->src_handle, iter->index);
+    struct cx_iterator_s *iter = it;
+    cx_array_list const* list = iter->src_handle.c;
+    if (iter->base.remove) {
+        iter->base.remove = false;
+        cx_arl_remove(iter->src_handle.m, iter->index);
     }
     iter->index--;
-    if (iter->index < list->base.size) {
+    if (iter->index < list->base.collection.size) {
         iter->elem_handle = ((char *) list->data)
-                            + iter->index * list->base.item_size;
+                            + iter->index * list->base.collection.elem_size;
     }
 }
 
-static bool cx_arl_iter_flag_rm(void *it) {
-    struct cx_iterator_base_s *iter = it;
-    if (iter->mutating) {
-        iter->remove = true;
-        return true;
-    } else {
-        return false;
-    }
-}
 
 static struct cx_iterator_s cx_arl_iterator(
         struct cx_list_s const *list,
@@ -479,12 +498,13 @@
     struct cx_iterator_s iter;
 
     iter.index = index;
-    iter.src_handle = list;
+    iter.src_handle.c = list;
     iter.elem_handle = cx_arl_at(list, index);
+    iter.elem_size = list->collection.elem_size;
+    iter.elem_count = list->collection.size;
     iter.base.valid = cx_arl_iter_valid;
     iter.base.current = cx_arl_iter_current;
     iter.base.next = backwards ? cx_arl_iter_prev : cx_arl_iter_next;
-    iter.base.flag_removal = cx_arl_iter_flag_rm;
     iter.base.remove = false;
     iter.base.mutating = false;
 
@@ -500,7 +520,7 @@
         cx_arl_clear,
         cx_arl_swap,
         cx_arl_at,
-        cx_arl_find,
+        cx_arl_find_remove,
         cx_arl_sort,
         cx_arl_compare,
         cx_arl_reverse,
@@ -510,7 +530,7 @@
 CxList *cxArrayListCreate(
         CxAllocator const *allocator,
         cx_compare_func comparator,
-        size_t item_size,
+        size_t elem_size,
         size_t initial_capacity
 ) {
     if (allocator == NULL) {
@@ -521,19 +541,20 @@
     if (list == NULL) return NULL;
 
     list->base.cl = &cx_array_list_class;
-    list->base.allocator = allocator;
-    list->base.cmpfunc = comparator;
+    list->base.collection.allocator = allocator;
     list->capacity = initial_capacity;
 
-    if (item_size > 0) {
-        list->base.item_size = item_size;
+    if (elem_size > 0) {
+        list->base.collection.elem_size = elem_size;
+        list->base.collection.cmpfunc = comparator;
     } else {
-        item_size = sizeof(void *);
+        elem_size = sizeof(void *);
+        list->base.collection.cmpfunc = comparator == NULL ? cx_cmp_ptr : comparator;
         cxListStorePointers((CxList *) list);
     }
 
-    // allocate the array after the real item_size is known
-    list->data = cxCalloc(allocator, initial_capacity, item_size);
+    // allocate the array after the real elem_size is known
+    list->data = cxCalloc(allocator, initial_capacity, elem_size);
     if (list->data == NULL) {
         cxFree(allocator, list);
         return NULL;