diff --git a/src/__internal/rbtree.h b/src/__internal/rbtree.h
index 8564bc1..01a5c10 100644
--- a/src/__internal/rbtree.h
+++ b/src/__internal/rbtree.h
@@ -29,17 +29,4 @@ extern rbnode_t* libcdsb_rbtree_node_delete(rbnode_t** root, rbnode_t* node)
 #define rbnode_is_empty(n) ((n) == rbnode_empty)
 #define rbnode_is_root(n)  rbnode_is_empty((n)->parent)
 
-extern void* libcdsb_rbtree_duplicate(const rbnode_t* s, void* (*node_duplicate)(void* src, void* parent, void* info), void* info)                                        wur__   Nonnull__(1);
-extern int   libcdsb_rbtree_compare  (const rbnode_t* s0, const rbnode_t* s1, int (*node_compare)(const rbnode_t* s0, const rbnode_t* s1, void* info), void* info) pure__ wur__ Nonnull__(1,2);
-
-extern hash_t libcdsb_rbtree_hash(const void* s, hash_t (*node_hash)(const void* s, void* info), void* info) pure__ wur__ Nonnull__(1);
-extern size_t libcdsb_rbtree_size(const void* s)                                                             pure__ wur__ Nonnull__(1);
-extern void   libcdsb_rbtree_free(void* x, void (*node_free)(void* x, void* info), void* info)                            Nonnull__(1);
-
-#define rbtree_duplicate libcdsb_rbtree_duplicate
-#define rbtree_compare   libcdsb_rbtree_compare
-#define rbtree_hash      libcdsb_rbtree_hash
-#define rbtree_size      libcdsb_rbtree_size
-#define rbtree_free      libcdsb_rbtree_free
-
 #endif /* LIBCDSB_SRC_INTERNAL_RBTREE_H */
diff --git a/src/map/base.c b/src/map/base.c
index de82733..026f180 100644
--- a/src/map/base.c
+++ b/src/map/base.c
@@ -3,89 +3,158 @@
 
 #include "include.h"
 
-#define mtree_duplicate(s, t)    rbtree_duplicate((rbnode_t*)s, (void*)mnode_duplicate, t)
-#define mtree_compare(s0, s1, t) rbtree_compare((void*)s0, (void*)s1, (void*)mnode_compare, (void*)t)
+/*#####################################################################################################################*/
 
-static mnode_t* mnode_duplicate(const mnode_t* s, mnode_t* p, const vtype* t) {
-    mnode_t* x;
-
-    x        = mnode_create(vnode_duplicate(&s->key, *t), p, s->colored);
-    x->type  = s->type;
-    x->value = vnode_duplicate(&s->value, s->type);
-
-    return x;
-}
-
-static int mnode_compare(const mnode_t* s0, const mnode_t* s1, vtype* t) {
-    int c = vnode_compare_eq(&s0->key, &s1->key, *t);
+static inline int mnode_compare(const mnode_t* s0, const mnode_t* s1, vtype t) {
+    int c = vnode_compare_eq(&s0->key, &s1->key, t);
 
     return !c ? vnode_compare(&s0->value, s0->type, &s1->value, s1->type) : c;
 }
 
-static hash_t mnode_hash(const mnode_t* s, vtype* tp) {
-    vtype t = (!is_null(tp)) ? *tp : VTYPE_POINTER;
-    return vnode_hash(s->key, t) + vnode_hash(s->value, s->type) + t;
-}
-
-void libcdsb_mnode_free(mnode_t* x, vtype* t) {
-    vnode_free(&x->key, *t);
-    vnode_free(&x->value, x->type);
+static inline hash_t mnode_hash(const mnode_t* s, vtype t) {
+    return vnode_hash(&s->key, t) + vnode_hash(&s->value, s->type) + t;
 }
 
 /*#####################################################################################################################*/
 
 hash_t map_hash(const map_t* s) {
-    return rbtree_hash(s->root, (void*)mnode_hash, (void*)&s->type) + VTYPE_MAP;
+
+    mnode_t *c0, *c1;
+    hash_t hash, v;
+    stack_t z;
+
+    if (mnode_is_empty(s->root)) return 0;
+
+    z.prev = 0;
+    hash   = 1;
+    c1     = s->root;
+
+    if (!rbnode_is_empty(z.value = c1->left)) {
+        do {
+            c0 = stack_pop(&z);
+            ++hash;
+
+            if (!mnode_is_empty(c0->right)) stack_push(&z, c1 = c0->right);
+            if (!mnode_is_empty(c0->left))  stack_push(&z, c1 = c0->left);
+        } while (!is_null(z.value));
+    }
+
+    v  = mnode_hash(c1, s->type);
+    c1 = s->root;
+
+    if (!rbnode_is_empty(z.value = c1->right)) {
+        do {
+            c0 = stack_pop(&z);
+            ++hash;
+
+            if (!mnode_is_empty(c0->right)) stack_push(&z, c1 = c0->right);
+            if (!mnode_is_empty(c0->left))  stack_push(&z, c1 = c0->left);
+        } while (!is_null(z.value));
+    }
+
+    v += mnode_hash(c1, s->type);
+
+    return (hash ^ v) + VTYPE_MAP;
 }
 
+/*#####################################################################################################################*/
+
 void map_init(map_t* x, vtype t) {
     x->root = mnode_empty;
     x->type = t;
 }
 
 void map_free(map_t* x) {
-    rbtree_free(x->root, (void*)mnode_free, &x->type);
+    mnode_t *t, *c;
+
+    c = x->root;
+
+    while (!mnode_is_empty(x->root)) {
+        if (!mnode_is_empty(c->left)) {
+            c = c->left;
+        } else if (!mnode_is_empty(c->right)) {
+            c = c->right;
+        } else if (!mnode_is_root(c)) {
+            vnode_free(&c->key,   x->type);
+            vnode_free(&c->value, c->type);
+
+            t = c;
+            c = c->parent;
+
+            if (t == c->left) c->left  = mnode_empty;
+            else              c->right = mnode_empty;
+
+            free(t);
+        } else {
+            vnode_free(&c->key,   x->type);
+            vnode_free(&c->value, c->type);
+            x->root = mnode_empty;
+        }
+    }
 
-    x->root = mnode_empty;
     x->type = 0;
 }
 
 /*#####################################################################################################################*/
 
 size_t map_size(const map_t* x) {
-    return rbtree_size(x->root);
+    stack_t   z = { .prev = 0, .value = x->root };
+    size_t    n = 0;
+    rbnode_t* c;
+
+    if (!mnode_is_empty(x->root)) {
+        while ((c = stack_pop(&z))) {
+            ++n;
+            if (!rbnode_is_empty(c->right)) stack_push(&z, c->right);
+            if (!rbnode_is_empty(c->left))  stack_push(&z, c->left);
+        }
+    }
+
+    return n;
 }
 
 /*#####################################################################################################################*/
 
 int map_compare(const map_t* s0, const map_t* s1) {
-    if (s0 == s1) return 0;
-    if (s0->type != s1->type) return s0->type - s1->type;
+    mnode_t *c0, *c1;
+    stack_t z;
+    int c = 0;
 
-    return mtree_compare(s0->root, s1->root, &s0->type);
-}
-
-/*#####################################################################################################################*/
-
-map_t map_copy(const map_t* s) {
-    map_t x;
-
-    x.type = s->type;
-    x.root = mtree_duplicate(s->root, &x.type);
-
-    return x;
-}
-
-map_t* map_duplicate(const map_t* s) {
-    map_t *x = malloc(sizeof(*x));
-
-    x->type = s->type;
-    x->root = mtree_duplicate(s->root, &x->type);
-
-    return x;
-}
-
-void map_copy_init(map_t* x, const map_t* s) {
-    x->type = s->type;
-    x->root = mtree_duplicate(s->root, &x->type);
+    if (s0 == s1 || s0->root == s1->root)
+        return 0;
+    if (s0->type != s1->type)
+        return s0->type - s1->type;
+
+    z.prev  = 0;
+    z.value = 0;
+
+    stack_push_many(&z, 2, (void*)s1, (void*)s0);
+
+    do {
+        c0 = stack_pop(&z);
+        c1 = stack_pop(&z);
+
+        if (mnode_is_empty(c0) || mnode_is_empty(c1)) {
+            if (c0 != c1) {
+                stack_flush(&z);
+                return mnode_is_empty(c0) ? -1 : 1;
+            }
+        } else if ((c = mnode_compare(c0, c1, s0->type))) {
+            if (c0->left == c1->right) {  // == mnode_empty
+                        c = mnode_compare(c0->right, c1, s0->type);
+                if (!c) c = mnode_compare(c0, c1->left, s0->type);
+            } else if (c0->right == c1->left) { // == mnode_empty
+                        c = mnode_compare(c0, c1->right, s0->type);
+                if (!c) c = mnode_compare(c0->left, c1, s0->type);
+            }
+
+            if (c) {
+                stack_flush(&z);
+                return c;
+            }
+        } else stack_push_many(&z, 4, c1->right, c0->right, c1->left, c0->left);
+
+    } while (!is_null(z.value));
+
+    return 0;
 }
diff --git a/src/map/copy.c b/src/map/copy.c
new file mode 100644
index 0000000..7a3948f
--- /dev/null
+++ b/src/map/copy.c
@@ -0,0 +1,113 @@
+/* This software is licensed by the MIT License, see LICENSE file */
+/*                                Copyright © 2022 Gregory Lirent */
+
+#include "include.h"
+
+/*#####################################################################################################################*/
+
+static inline mnode_t* mnode_duplicate(const mnode_t* s, mnode_t* p, const vtype t) {
+    mnode_t* x;
+
+    x        = mnode_create(vnode_duplicate(&s->key, t), p, s->colored);
+    x->type  = s->type;
+    x->value = vnode_duplicate(&s->value, s->type);
+
+    return x;
+}
+
+/*#####################################################################################################################*/
+
+map_t map_copy(const map_t* s) {
+
+    map_t   x;
+    stack_t z = { .prev = 0, .value = s->root };
+
+    x.type = s->type;
+
+    if (!mnode_is_empty(s->root)) {
+        x.root = mnode_duplicate(s->root, mnode_empty, s->type);
+        stack_push(&z, x.root);
+
+        do {
+            mnode_t *p0 = stack_pop(&z);
+            mnode_t *p1 = stack_pop(&z);
+
+            if (!mnode_is_empty(p1->left)) {
+                p0->left = mnode_duplicate(p1->left, p0, s->type);
+                stack_push_many(&z, 2, p1->left, p0->left);
+            }
+
+            if (!mnode_is_empty(p1->right)) {
+                p0->right = mnode_duplicate(p1->right, p0, s->type);
+                stack_push_many(&z, 2, p1->right, p0->right);
+            }
+
+        } while (!is_null(z.value));
+
+    } else x.root = mnode_empty;
+
+    return x;
+}
+
+
+map_t* map_duplicate(const map_t* s) {
+
+    map_t*  x = malloc(sizeof(*x));
+    stack_t z = { .prev = 0, .value = s->root };
+
+    x->type = s->type;
+
+    if (!mnode_is_empty(s->root)) {
+        x->root = mnode_duplicate(s->root, mnode_empty, s->type);
+        stack_push(&z, x->root);
+
+        do {
+            mnode_t *p0 = stack_pop(&z);
+            mnode_t *p1 = stack_pop(&z);
+
+            if (!mnode_is_empty(p1->left)) {
+                p0->left = mnode_duplicate(p1->left, p0, s->type);
+                stack_push_many(&z, 2, p1->left, p0->left);
+            }
+
+            if (!mnode_is_empty(p1->right)) {
+                p0->right = mnode_duplicate(p1->right, p0, s->type);
+                stack_push_many(&z, 2, p1->right, p0->right);
+            }
+
+        } while (!is_null(z.value));
+
+    } else x->root = mnode_empty;
+
+    return x;
+}
+
+
+void map_copy_init(map_t* x, const map_t* s) {
+
+    stack_t z = { .prev = 0, .value = s->root };
+
+    x->type = s->type;
+
+    if (!mnode_is_empty(s->root)) {
+        x->root = mnode_duplicate(s->root, mnode_empty, s->type);
+        stack_push(&z, x->root);
+
+        do {
+            mnode_t *p0 = stack_pop(&z);
+            mnode_t *p1 = stack_pop(&z);
+
+            if (!mnode_is_empty(p1->left)) {
+                p0->left = mnode_duplicate(p1->left, p0, s->type);
+                stack_push_many(&z, 2, p1->left, p0->left);
+            }
+
+            if (!mnode_is_empty(p1->right)) {
+                p0->right = mnode_duplicate(p1->right, p0, s->type);
+                stack_push_many(&z, 2, p1->right, p0->right);
+            }
+
+        } while (!is_null(z.value));
+
+    } else x->root = mnode_empty;
+}
diff --git a/src/map/extra.c b/src/map/extra.c
index 5f28450..b587b17 100644
--- a/src/map/extra.c
+++ b/src/map/extra.c
@@ -20,7 +20,8 @@ bool libcdsb_map_update(map_t* x, const void* k, vtype kt, const void* v, vtype
             cmp = vtype_compare(k, kt, vnode_peek(&n->key, kt), kt);
 
             if (cmp == 0) {
-                mnode_free(n, &kt);
+                vnode_free(&n->key,   x->type);
+                vnode_free(&n->value, n->type);
 
                 n->key   = kn;
                 n->value = vnode_create(v, vt);
@@ -65,7 +66,8 @@ int libcdsb_map_find(map_t* x, const void* k, vtype t, void* _, map_access_callb
 
             if (cut) {
                 c = mnode_delete(&x->root, c);
-                mnode_free(c, &x->type);
+                vnode_free(&c->key,   x->type);
+                vnode_free(&c->value, c->type);
                 free(c);
             }
 
@@ -92,7 +94,8 @@ int libcdsb_map_foreach(map_t* x, void* dt, map_access_callback callback, bool f
         if (!mnode_is_empty(c->left))  stack_push(&z, c->left);
 
         if (flush) {
-            mnode_free(c, &x->type);
+            vnode_free(&c->key,   x->type);
+            vnode_free(&c->value, c->type);
             free(c);
         }
     }
@@ -102,7 +105,8 @@ int libcdsb_map_foreach(map_t* x, void* dt, map_access_callback callback, bool f
             if (!mnode_is_empty(c->right)) stack_push(&z, c->right);
             if (!mnode_is_empty(c->left))  stack_push(&z, c->left);
 
-            mnode_free(c, &x->type);
+            vnode_free(&c->key,   x->type);
+            vnode_free(&c->value, c->type);
             free(c);
 
             c = stack_pop(&z);
diff --git a/src/map/include.h b/src/map/include.h
index 59f1c5b..fe07b6b 100644
--- a/src/map/include.h
+++ b/src/map/include.h
@@ -28,8 +28,6 @@ static_assert(offsetof(struct libcdsb_rbtree_node, value) == offsetof(struct lib
 static_assert(offsetof(struct libcdsb_set, root) == offsetof(struct libcdsb_map, root), "Implementation assert");
 static_assert(offsetof(struct libcdsb_set, type) == offsetof(struct libcdsb_map, type), "Implementation assert");
 
-extern void libcdsb_mnode_free(mnode_t* x, vtype* t);
-
 #define mnode_empty           ((mnode_t*)LIBCDSB_RBTREE_NODE_EMPTY)
 #define mnode_create(k, p, c) ((mnode_t*)libcdsb_rbtree_node_create(k, (rbnode_t*)p, c, sizeof(mnode_t)))
 #define mnode_fixup(r, n)     libcdsb_rbtree_node_fixup((rbnode_t**)(r), (rbnode_t*)(n))
@@ -38,6 +36,4 @@ extern void libcdsb_mnode_free(mnode_t* x, vtype* t);
 #define mnode_is_empty(n) ((n) == mnode_empty)
 #define mnode_is_root(n)  mnode_is_empty((n)->parent)
 
-#define mnode_free libcdsb_mnode_free
-
 #endif /* LIBCDSB_SRC_MAP_INCLUDE_H */
diff --git a/src/rbtree-extra.c b/src/rbtree-extra.c
deleted file mode 100644
index 40b2821..0000000
--- a/src/rbtree-extra.c
+++ /dev/null
@@ -1,206 +0,0 @@
-/* This software is licensed by the MIT License, see LICENSE file */
-/*                                Copyright © 2022 Gregory Lirent */
-
-#include "__internal/rbtree.h"
-
-/*#####################################################################################################################*/
-
-static rbnode_t* rbnode_duplicate(const rbnode_t* s, rbnode_t* p, const vtype* info) {
-    return rbnode_create(vnode_duplicate(&s->value, (info) ? *info : VTYPE_POINTER), p, s->colored);
-}
-
-static int rbnode_compare(const rbnode_t* s0, const rbnode_t* s1, vtype* tp) {
-    vtype t = !is_null(tp) ? *tp : VTYPE_POINTER;
-    return vnode_compare(s0->value, t, s1->value, t);
-}
-
-static hash_t rbnode_hash(const rbnode_t* s, vtype* tp) {
-    vtype t = (!is_null(tp)) ? *tp : VTYPE_POINTER;
-    return vnode_hash(s->value, t);
-}
-
-static void rbnode_free(rbnode_t* x, vtype *t) {
-    if (!is_null(t)) vnode_free(&x->value, *t);
-}
-
-/*#####################################################################################################################*/
-
-hash_t libcdsb_rbtree_hash(const void* s, hash_t (*node_hash)(const void* s, void* info), void* info) {
-
-    rbnode_t *c0, *c1;
-    hash_t hash, v;
-    stack_t z;
-
-    if (rbnode_is_empty(s)) return 0;
-    if (is_null(node_hash)) node_hash = (void*)rbnode_hash;
-
-    z.prev = 0;
-    hash   = 1;
-    c1     = (void*)s;
-
-    if (!rbnode_is_empty(z.value = c1->left)) do {
-        c0 = stack_pop(&z);
-        ++hash;
-        if (!rbnode_is_empty(c0->left))
-            stack_push(&z, c1 = c0->left);
-        if (!rbnode_is_empty(c0->right))
-            stack_push(&z, c0->right);
-    } while (!is_null(z.value));
-
-    v  = node_hash(c1, info);
-    c1 = (void*)s;
-
-    if (!rbnode_is_empty(z.value = c1->right)) do {
-        c0 = stack_pop(&z);
-        ++hash;
-        if (!rbnode_is_empty(c0->left))
-            stack_push(&z, c1 = c0->left);
-        if (!rbnode_is_empty(c0->right))
-            stack_push(&z, c0->right);
-    } while (!is_null(z.value));
-
-    v += node_hash(c1, info);
-
-    return hash ^ v;
-}
-
-/*#####################################################################################################################*/
-
-void* libcdsb_rbtree_duplicate(const rbnode_t* s, void* (*node_duplicate)(void* src, void* parent, void* info), void* info) {
-    rbnode_t *p0, *p1, *x;
-    stack_t   z;
-
-    z.prev = 0;
-    z.value = (void*)s;
-
-    if (is_null(node_duplicate)) {
-        node_duplicate = (void*)rbnode_duplicate;
-    }
-
-    if (!rbnode_is_empty(s)) {
-        x = node_duplicate(z.value, rbnode_empty, info);
-        stack_push(&z, x);
-
-        do {
-            p0 = stack_pop(&z);
-            p1 = stack_pop(&z);
-
-            if (!rbnode_is_empty(p1->left)) {
-                p0->left = node_duplicate(p1->left, p0, info);
-
-                stack_push(&z, p1->left);
-                stack_push(&z, p0->left);
-            }
-
-            if (!rbnode_is_empty(p1->right)) {
-                p0->right = node_duplicate(p1->right, p0, info);
-
-                stack_push(&z, p1->right);
-                stack_push(&z, p0->right);
-            }
-
-        } while (!is_null(z.value));
-
-    } else x = rbnode_empty;
-
-    return x;
-}
-
-/*#####################################################################################################################*/
-
-int libcdsb_rbtree_compare(const rbnode_t* s0, const rbnode_t* s1, int (*node_compare)(const rbnode_t* s0, const rbnode_t* s1, void* info), void* info) {
-
-    rbnode_t *c0, *c1;
-    stack_t z;
-    int c = 0;
-
-    if (s0 == s1) return 0;
-    if (is_null(node_compare)) node_compare = (void*)rbnode_compare;
-
-    z.prev  = 0;
-    z.value = 0;
-
-    stack_push(&z, (void*)s1);
-    stack_push(&z, (void*)s0);
-
-    do {
-        c0 = stack_pop(&z);
-        c1 = stack_pop(&z);
-
-        if (rbnode_is_empty(c0) || rbnode_is_empty(c1)) {
-            if (c0 != c1) {
-                stack_flush(&z);
-                return rbnode_is_empty(c0) ? -1 : 1;
-            }
-        } else if ((c = node_compare(c0, c1, info))) {
-            if (c0->left == c1->right) {  // <-- rbnode_empty
-                c = node_compare(c0->right, c1, info);
-                if (!c) c = node_compare(c0, c1->left, info);
-            } else if (c0->right == c1->left) { // <-- rbnode_empty
-                c = node_compare(c0, c1->right, info);
-                if (!c) c = node_compare(c0->left, c1, info);
-            }
-
-            if (c) {
-                stack_flush(&z);
-                return c;
-            }
-        } else {
-            stack_push(&z, c1->right);
-            stack_push(&z, c0->right);
-            stack_push(&z, c1->left);
-            stack_push(&z, c0->left);
-        }
-
-    } while (!is_null(z.value));
-
-    return 0;
-}
-
-
-size_t libcdsb_rbtree_size(const void* s) {
-    stack_t   z = { .prev = 0, .value = (void*)s };
-    size_t    n = 0;
-    rbnode_t* c;
-
-    if (!rbnode_is_empty(s)) {
-        while ((c = stack_pop(&z))) {
-            ++n;
-            if (!rbnode_is_empty(c->left))
-                stack_push(&z, c->left);
-            if (!rbnode_is_empty(c->right))
-                stack_push(&z, c->right);
-        }
-    }
-
-    return n;
-}
-
-
-void libcdsb_rbtree_free(void* x, void (*node_free)(void* x, void* info), void* info) {
-    rbnode_t *t, *c;
-
-    c = x;
-    if (is_null(node_free)) node_free = (void*)rbnode_free;
-
-    while (!rbnode_is_empty(x)) {
-        if (!rbnode_is_empty(c->left)) {
-            c = c->left;
-        } else if (!rbnode_is_empty(c->right)) {
-            c = c->right;
-        } else if (!rbnode_is_root(c)) {
-            node_free(c, info);
-
-            t = c;
-            c = c->parent;
-
-            if (t == c->left) c->left  = rbnode_empty;
-            else              c->right = rbnode_empty;
-
-            free(t);
-        } else {
-            node_free(c, info);
-            x = rbnode_empty;
-        }
-    }
-}
diff --git a/src/set/base.c b/src/set/base.c
index 17d5427..f10f02b 100644
--- a/src/set/base.c
+++ b/src/set/base.c
@@ -6,10 +6,58 @@
 
 /*#####################################################################################################################*/
 
-hash_t vset_hash(const set_t* s) {
-    return rbtree_hash(s->root, nullptr, (void*)&s->type) + VTYPE_SET;
+static inline int rbnode_compare(const rbnode_t* s0, const rbnode_t* s1, vtype t) {
+    return vnode_compare(s0->value, t, s1->value, t);
 }
 
+static inline hash_t rbnode_hash(const rbnode_t* s, vtype t) {
+    return vnode_hash(&s->value, t);
+}
+
+/*#####################################################################################################################*/
+
+hash_t vset_hash(const set_t* s) {
+
+    rbnode_t *c0, *c1;
+    hash_t hash, v;
+    stack_t z;
+
+    if (rbnode_is_empty(s->root)) return 0;
+
+    z.prev = 0;
+    hash   = 1;
+    c1     = s->root;
+
+    if (!rbnode_is_empty(z.value = c1->left)) {
+        do {
+            c0 = stack_pop(&z);
+            ++hash;
+
+            if (!rbnode_is_empty(c0->right)) stack_push(&z, c1 = c0->right);
+            if (!rbnode_is_empty(c0->left))  stack_push(&z, c1 = c0->left);
+        } while (!is_null(z.value));
+    }
+
+    v  = rbnode_hash(c1, s->type);
+    c1 = s->root;
+
+    if (!rbnode_is_empty(z.value = c1->right)) {
+        do {
+            c0 = stack_pop(&z);
+            ++hash;
+
+            if (!rbnode_is_empty(c0->right)) stack_push(&z, c1 = c0->right);
+            if (!rbnode_is_empty(c0->left))  stack_push(&z, c1 = c0->left);
+        } while (!is_null(z.value));
+    }
+
+    v += rbnode_hash(c1, s->type);
+
+    return (hash ^ v) + VTYPE_SET;
+}
+
+/*#####################################################################################################################*/
+
 void vset_init(set_t* x, vtype t) {
     x->root = rbnode_empty;
     x->type = t;
@@ -17,48 +65,94 @@ void vset_init(set_t* x, vtype t) {
 
 
 void vset_free(set_t* x) {
-    rbtree_free(x->root, nullptr, &x->type);
+    rbnode_t *t, *c;
+
+    c = x->root;
+
+    while (!rbnode_is_empty(x->root)) {
+        if (!rbnode_is_empty(c->left)) {
+            c = c->left;
+        } else if (!rbnode_is_empty(c->right)) {
+            c = c->right;
+        } else if (!rbnode_is_root(c)) {
+            vnode_free(&c->value, x->type);
+
+            t = c;
+            c = c->parent;
+
+            if (t == c->left) c->left  = rbnode_empty;
+            else              c->right = rbnode_empty;
+
+            free(t);
+        } else {
+            vnode_free(&c->value, x->type);
+            x->root = rbnode_empty;
+        }
+    }
 
-    x->root = rbnode_empty;
     x->type = 0;
 }
 
 /*#####################################################################################################################*/
 
 size_t vset_size(const set_t* x) {
-    return rbtree_size(x->root);
+    stack_t   z = { .prev = 0, .value = x->root };
+    size_t    n = 0;
+    rbnode_t* c;
+
+    if (!rbnode_is_empty(x->root)) {
+        while ((c = stack_pop(&z))) {
+            ++n;
+            if (!rbnode_is_empty(c->right)) stack_push(&z, c->right);
+            if (!rbnode_is_empty(c->left))  stack_push(&z, c->left);
+        }
+    }
+
+    return n;
 }
 
 /*#####################################################################################################################*/
 
 int vset_compare(const set_t* s0, const set_t* s1) {
-    if (s0 == s1) return 0;
-    if (s0->type != s1->type) return s0->type - s1->type;
+    rbnode_t *c0, *c1;
+    stack_t z;
+    int c = 0;
 
-    return rbtree_compare(s0->root, s1->root, nullptr, (void*)&s0->type);
-}
-
-/*#####################################################################################################################*/
-
-set_t vset_copy(const set_t* s) {
-    set_t x;
-
-    x.type = s->type;
-    x.root = rbtree_duplicate(s->root, nullptr, &x.type);
-
-    return x;
-}
-
-set_t* vset_duplicate(const set_t* s) {
-    set_t *x = malloc(sizeof(*x));
-
-    x->type = s->type;
-    x->root = rbtree_duplicate(s->root, nullptr, &x->type);
-
-    return x;
-}
-
-void vset_copy_init(set_t* x, const set_t* s) {
-    x->type = s->type;
-    x->root = rbtree_duplicate(s->root, nullptr, &x->type);
+    if (s0 == s1 || s0->root == s1->root)
+        return 0;
+    if (s0->type != s1->type)
+        return s0->type - s1->type;
+
+    z.prev  = 0;
+    z.value = 0;
+
+    stack_push_many(&z, 2, (void*)s1, (void*)s0);
+
+    do {
+        c0 = stack_pop(&z);
+        c1 = stack_pop(&z);
+
+        if (rbnode_is_empty(c0) || rbnode_is_empty(c1)) {
+            if (c0 != c1) {
+                stack_flush(&z);
+                return rbnode_is_empty(c0) ? -1 : 1;
+            }
+        } else if ((c = rbnode_compare(c0, c1, s0->type))) {
+            if (c0->left == c1->right) {  // == rbnode_empty
+                        c = rbnode_compare(c0->right, c1, s0->type);
+                if (!c) c = rbnode_compare(c0, c1->left, s0->type);
+            } else if (c0->right == c1->left) { // == rbnode_empty
+                        c = rbnode_compare(c0, c1->right, s0->type);
+                if (!c) c = rbnode_compare(c0->left, c1, s0->type);
+            }
+
+            if (c) {
+                stack_flush(&z);
+                return c;
+            }
+        } else stack_push_many(&z, 4, c1->right, c0->right, c1->left, c0->left);
+
+    } while (!is_null(z.value));
+
+    return 0;
 }
diff --git a/src/set/copy.c b/src/set/copy.c
new file mode 100644
index 0000000..a074b0b
--- /dev/null
+++ b/src/set/copy.c
@@ -0,0 +1,97 @@
+/* This software is licensed by the MIT License, see LICENSE file */
+/*                                Copyright © 2022 Gregory Lirent */
+
+#include "../../include/set.h"
+#include "../__internal/rbtree.h"
+
+set_t vset_copy(const set_t* s) {
+
+    set_t   x = { .type = s->type };
+    stack_t z = { .prev = 0, .value = s->root };
+    vtype   t = s->type;
+
+    if (!rbnode_is_empty(s->root)) {
+        x.root = rbnode_create(vnode_duplicate(&s->root->value, t), rbnode_empty, 0);
+        stack_push(&z, x.root);
+
+        do {
+            rbnode_t *p0 = stack_pop(&z);
+            rbnode_t *p1 = stack_pop(&z);
+
+            if (!rbnode_is_empty(p1->left)) {
+                p0->left = rbnode_create(vnode_duplicate(&p1->left->value, t), p0, p1->left->colored);
+                stack_push_many(&z, 2, p1->left, p0->left);
+            }
+
+            if (!rbnode_is_empty(p1->right)) {
+                p0->right = rbnode_create(vnode_duplicate(&p1->right->value, t), p0, p1->right->colored);
+                stack_push_many(&z, 2, p1->right, p0->right);
+            }
+
+        } while (!is_null(z.value));
+
+    } else x.root = rbnode_empty;
+
+    return x;
+}
+
+
+set_t* vset_duplicate(const set_t* s) {
+
+    set_t*  x = malloc(sizeof(*x));
+    stack_t z = { .prev = 0, .value = s->root };
+    vtype   t = x->type = s->type;
+
+    if (!rbnode_is_empty(s->root)) {
+        x->root = rbnode_create(vnode_duplicate(&s->root->value, t), rbnode_empty, 0);
+        stack_push(&z, x->root);
+
+        do {
+            rbnode_t *p0 = stack_pop(&z);
+            rbnode_t *p1 = stack_pop(&z);
+
+            if (!rbnode_is_empty(p1->left)) {
+                p0->left = rbnode_create(vnode_duplicate(&p1->left->value, t), p0, p1->left->colored);
+                stack_push_many(&z, 2, p1->left, p0->left);
+            }
+
+            if (!rbnode_is_empty(p1->right)) {
+                p0->right = rbnode_create(vnode_duplicate(&p1->right->value, t), p0, p1->right->colored);
+                stack_push_many(&z, 2, p1->right, p0->right);
+            }
+
+        } while (!is_null(z.value));
+
+    } else x->root = rbnode_empty;
+
+    return x;
+}
+
+
+void vset_copy_init(set_t* x, const set_t* s) {
+
+    stack_t z = { .prev = 0, .value = s->root };
+    vtype   t = x->type = s->type;
+
+    if (!rbnode_is_empty(s->root)) {
+        x->root = rbnode_create(vnode_duplicate(&s->root->value, t), rbnode_empty, 0);
+        stack_push(&z, x->root);
+
+        do {
+            rbnode_t *p0 = stack_pop(&z);
+            rbnode_t *p1 = stack_pop(&z);
+
+            if (!rbnode_is_empty(p1->left)) {
+                p0->left = rbnode_create(vnode_duplicate(&p1->left->value, t), p0, p1->left->colored);
+                stack_push_many(&z, 2, p1->left, p0->left);
+            }
+
+            if (!rbnode_is_empty(p1->right)) {
+                p0->right = rbnode_create(vnode_duplicate(&p1->right->value, t), p0, p1->right->colored);
+                stack_push_many(&z, 2, p1->right, p0->right);
+            }
+
+        } while (!is_null(z.value));
+
+    } else x->root = rbnode_empty;
+}