diff -r dfd0403ff8b6 -r 2e6e9d9f2159 src/linked_list.c
--- a/src/linked_list.c	Wed Feb 08 18:56:58 2023 +0100
+++ b/src/linked_list.c	Wed Feb 08 20:26:09 2023 +0100
@@ -451,6 +451,8 @@
 
 // HIGH LEVEL LINKED LIST IMPLEMENTATION
 
+bool CX_DISABLE_LINKED_LIST_SWAP_SBO = false;
+
 typedef struct cx_linked_list_node cx_linked_list_node;
 struct cx_linked_list_node {
     cx_linked_list_node *prev;
@@ -577,6 +579,126 @@
     return 0;
 }
 
+#ifndef CX_LINKED_LIST_SWAP_SBO_SIZE
+#define CX_LINKED_LIST_SWAP_SBO_SIZE 16
+#endif
+
+static int cx_ll_swap(
+        struct cx_list_s *list,
+        size_t i,
+        size_t j
+) {
+    if (i >= list->size || j >= list->size) return 1;
+    if (i == j) return 0;
+
+    // perform an optimized search that finds both elements in one run
+    cx_linked_list *ll = (cx_linked_list *) list;
+    size_t mid = list->size / 2;
+    size_t left, right;
+    if (i < j) {
+        left = i;
+        right = j;
+    } else {
+        left = j;
+        right = i;
+    }
+    cx_linked_list_node *nleft, *nright;
+    if (left < mid && right < mid) {
+        // case 1: both items left from mid
+        nleft = cx_ll_node_at(ll, left);
+        nright = nleft;
+        for (size_t c = left; c < right; c++) {
+            nright = nright->next;
+        }
+    } else if (left >= mid && right >= mid) {
+        // case 2: both items right from mid
+        nright = cx_ll_node_at(ll, right);
+        nleft = nright;
+        for (size_t c = right; c > left; c--) {
+            nleft = nleft->prev;
+        }
+    } else {
+        // case 3: one item left, one item right
+
+        // chose the closest to begin / end
+        size_t closest;
+        size_t other;
+        size_t diff2boundary = list->size - right - 1;
+        if (left <= diff2boundary) {
+            closest = left;
+            other = right;
+            nleft = cx_ll_node_at(ll, left);
+        } else {
+            closest = right;
+            other = left;
+            diff2boundary = left;
+            nright = cx_ll_node_at(ll, right);
+        }
+
+        // is other element closer to us or closer to boundary?
+        if (right - left <= diff2boundary) {
+            // search other element starting from already found element
+            if (closest == left) {
+                nright = nleft;
+                for (size_t c = left; c < right; c++) {
+                    nright = nright->next;
+                }
+            } else {
+                nleft = nright;
+                for (size_t c = right; c > left; c--) {
+                    nleft = nleft->prev;
+                }
+            }
+        } else {
+            // search other element starting at the boundary
+            if (closest == left) {
+                nright = cx_ll_node_at(ll, other);
+            } else {
+                nleft = cx_ll_node_at(ll, other);
+            }
+        }
+    }
+
+    if (list->itemsize > CX_LINKED_LIST_SWAP_SBO_SIZE || CX_DISABLE_LINKED_LIST_SWAP_SBO) {
+        cx_linked_list_node *prev = nleft->prev;
+        cx_linked_list_node *next = nright->next;
+        cx_linked_list_node *midstart = nleft->next;
+        cx_linked_list_node *midend = nright->prev;
+
+        if (prev == NULL) {
+            ll->begin = nright;
+        } else {
+            prev->next = nright;
+        }
+        nright->prev = prev;
+        if (midstart == nright) {
+            // special case: both nodes are adjacent
+            nright->next = nleft;
+            nleft->prev = nright;
+        } else {
+            // likely case: a chain is between the two nodes
+            nright->next = midstart;
+            midstart->prev = nright;
+            midend->next = nleft;
+            nleft->prev = midend;
+        }
+        nleft->next = next;
+        if (next == NULL) {
+            ll->end = nleft;
+        } else {
+            next->prev = nleft;
+        }
+    } else {
+        // swap payloads to avoid relinking
+        char buf[CX_LINKED_LIST_SWAP_SBO_SIZE];
+        memcpy(buf, nleft->payload, list->itemsize);
+        memcpy(nleft->payload, nright->payload, list->itemsize);
+        memcpy(nright->payload, buf, list->itemsize);
+    }
+
+    return 0;
+}
+
 static void *cx_ll_at(
         struct cx_list_s const *list,
         size_t index
@@ -714,6 +836,7 @@
         cx_ll_insert_array,
         cx_ll_insert_iter,
         cx_ll_remove,
+        cx_ll_swap,
         cx_ll_at,
         cx_ll_find,
         cx_ll_sort,