diff -r 21274e5950af -r a1f4cb076d2f src/ucx/map.c
--- a/src/ucx/map.c	Tue Aug 13 22:14:32 2019 +0200
+++ b/src/ucx/map.c	Sat Sep 24 16:26:10 2022 +0200
@@ -1,7 +1,7 @@
 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
  *
- * Copyright 2016 Olaf Wintermann. All rights reserved.
+ * Copyright 2017 Mike Becker, Olaf Wintermann All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -26,11 +26,11 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "ucx/map.h"
+
 #include <stdlib.h>
 #include <string.h>
 
-#include "map.h"
-
 UcxMap *ucx_map_new(size_t size) {
     return ucx_map_new_a(NULL, size);
 }
@@ -86,7 +86,11 @@
     UcxMapIterator iter = ucx_map_iterator(map);
     void *val;
     UCX_MAP_FOREACH(key, val, iter) {
-        destr(val);
+        if (destr) {
+            destr(val);
+        } else {
+            alfree(map->allocator, val);
+        }
     }
 }
 
@@ -99,8 +103,7 @@
     map->count = 0;
 }
 
-int ucx_map_copy(UcxMap *restrict from, UcxMap *restrict to,
-        copy_func fnc, void *data) {
+int ucx_map_copy(UcxMap const *from, UcxMap *to, copy_func fnc, void *data) {
     UcxMapIterator i = ucx_map_iterator(from);
     void *value;
     UCX_MAP_FOREACH(key, value, i) {
@@ -111,9 +114,14 @@
     return 0;
 }
 
-UcxMap *ucx_map_clone(UcxMap *map, copy_func fnc, void *data) {
+UcxMap *ucx_map_clone(UcxMap const *map, copy_func fnc, void *data) {
+    return ucx_map_clone_a(ucx_default_allocator(), map, fnc, data);
+}
+
+UcxMap *ucx_map_clone_a(UcxAllocator *allocator,
+        UcxMap const *map, copy_func fnc, void *data) {
     size_t bs = (map->count * 5) >> 1;
-    UcxMap *newmap = ucx_map_new(bs > map->size ? bs : map->size);
+    UcxMap *newmap = ucx_map_new_a(allocator, bs > map->size ? bs : map->size);
     if (!newmap) {
         return NULL;
     }
@@ -151,19 +159,22 @@
     UcxAllocator *allocator = map->allocator;
     
     if (key.hash == 0) {
-        key.hash = ucx_hash((char*)key.data, key.len);
+        key.hash = ucx_hash((const char*)key.data, key.len);
     }
+    
+    struct UcxMapKey mapkey;
+    mapkey.hash = key.hash;
 
-    size_t slot = key.hash%map->size;
-    UcxMapElement *restrict elm = map->map[slot];
-    UcxMapElement *restrict prev = NULL;
+    size_t slot = mapkey.hash%map->size;
+    UcxMapElement *elm = map->map[slot];
+    UcxMapElement *prev = NULL;
 
-    while (elm && elm->key.hash < key.hash) {
+    while (elm && elm->key.hash < mapkey.hash) {
         prev = elm;
         elm = elm->next;
     }
     
-    if (!elm || elm->key.hash != key.hash) {
+    if (!elm || elm->key.hash != mapkey.hash) {
         UcxMapElement *e = (UcxMapElement*)almalloc(
                 allocator, sizeof(UcxMapElement));
         if (!e) {
@@ -185,8 +196,9 @@
             return -1;
         }
         memcpy(kd, key.data, key.len);
-        key.data = kd;
-        elm->key = key;
+        mapkey.data = kd;
+        mapkey.len = key.len;
+        elm->key = mapkey;
         map->count++;
     }
     elm->data = data;
@@ -194,14 +206,14 @@
     return 0;
 }
 
-void* ucx_map_get_and_remove(UcxMap *map, UcxKey key, _Bool remove) {
+static void* ucx_map_get_and_remove(UcxMap *map, UcxKey key, int remove) {
     if(key.hash == 0) {
-        key.hash = ucx_hash((char*)key.data, key.len);
+        key.hash = ucx_hash((const char*)key.data, key.len);
     }
     
     size_t slot = key.hash%map->size;
-    UcxMapElement *restrict elm = map->map[slot];
-    UcxMapElement *restrict pelm = NULL;
+    UcxMapElement *elm = map->map[slot];
+    UcxMapElement *pelm = NULL;
     while (elm && elm->key.hash <= key.hash) {
         if(elm->key.hash == key.hash) {
             int n = (key.len > elm->key.len) ? elm->key.len : key.len;
@@ -228,19 +240,19 @@
     return NULL;
 }
 
-void *ucx_map_get(UcxMap *map, UcxKey key) {
-    return ucx_map_get_and_remove(map, key, 0);
+void *ucx_map_get(UcxMap const *map, UcxKey key) {
+    return ucx_map_get_and_remove((UcxMap *)map, key, 0);
 }
 
 void *ucx_map_remove(UcxMap *map, UcxKey key) {
     return ucx_map_get_and_remove(map, key, 1);
 }
 
-UcxKey ucx_key(void *data, size_t len) {
+UcxKey ucx_key(const void *data, size_t len) {
     UcxKey key;
     key.data = data;
     key.len = len;
-    key.hash = ucx_hash((const char*) data, len);
+    key.hash = ucx_hash((const char*)data, len);
     return key;
 }
 
@@ -287,7 +299,7 @@
     return h;
 }
 
-UcxMapIterator ucx_map_iterator(UcxMap *map) {
+UcxMapIterator ucx_map_iterator(UcxMap const *map) {
     UcxMapIterator i;
     i.map = map;
     i.cur = NULL;
@@ -309,7 +321,9 @@
             if (e->data) {
                 i->cur = e;
                 *elm = e->data;
-                *key = e->key;
+                key->data = e->key.data;
+                key->hash = e->key.hash;
+                key->len = e->key.len;
                 return 1;
             }
 
@@ -326,3 +340,63 @@
     return 0;
 }
 
+UcxMap* ucx_map_union(const UcxMap *first, const UcxMap *second,
+                      copy_func cpfnc, void* cpdata) {
+    return ucx_map_union_a(ucx_default_allocator(),
+            first, second, cpfnc, cpdata);
+}
+
+UcxMap* ucx_map_union_a(UcxAllocator *allocator,
+                        const UcxMap *first, const UcxMap *second,
+                        copy_func cpfnc, void* cpdata) {
+    UcxMap* result = ucx_map_clone_a(allocator, first, cpfnc, cpdata);
+    ucx_map_copy(second, result, cpfnc, cpdata);
+    return result;
+}
+
+UcxMap* ucx_map_intersection(const UcxMap *first, const UcxMap *second,
+                             copy_func cpfnc, void* cpdata) {
+    return ucx_map_intersection_a(ucx_default_allocator(),
+            first, second, cpfnc, cpdata);
+}
+
+UcxMap* ucx_map_intersection_a(UcxAllocator *allocator,
+                               const UcxMap *first, const UcxMap *second,
+                               copy_func cpfnc, void* cpdata) {
+    UcxMap *result = ucx_map_new_a(allocator, first->size < second->size ?
+            first->size : second->size);
+
+    UcxMapIterator iter = ucx_map_iterator(first);
+    void* value;
+    UCX_MAP_FOREACH(key, value, iter) {
+        if (ucx_map_get(second, key)) {
+            ucx_map_put(result, key, cpfnc ? cpfnc(value, cpdata) : value);
+        }
+    }
+
+    return result;
+}
+
+UcxMap* ucx_map_difference(const UcxMap *first, const UcxMap *second,
+                           copy_func cpfnc, void* cpdata) {
+    return ucx_map_difference_a(ucx_default_allocator(),
+            first, second, cpfnc, cpdata);
+}
+
+UcxMap* ucx_map_difference_a(UcxAllocator *allocator,
+                             const UcxMap *first, const UcxMap *second,
+                             copy_func cpfnc, void* cpdata) {
+
+    UcxMap *result = ucx_map_new_a(allocator, first->size - second->count);
+
+    UcxMapIterator iter = ucx_map_iterator(first);
+    void* value;
+    UCX_MAP_FOREACH(key, value, iter) {
+        if (!ucx_map_get(second, key)) {
+            ucx_map_put(result, key, cpfnc ? cpfnc(value, cpdata) : value);
+        }
+    }
+
+    ucx_map_rehash(result);
+    return result;
+}
\ No newline at end of file