diff -r 809581724cc7 -r 0358f1d9c506 ucx/hash_key.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/hash_key.c	Mon May 22 16:17:26 2023 +0200
@@ -0,0 +1,112 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 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:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "cx/hash_key.h"
+#include <string.h>
+
+void cx_hash_murmur(CxHashKey *key) {
+    unsigned char const *data = key->data;
+    if (data == NULL) {
+        // extension: special value for NULL
+        key->hash = 1574210520u;
+        return;
+    }
+    size_t len = key->len;
+
+    unsigned m = 0x5bd1e995;
+    unsigned r = 24;
+    unsigned h = 25 ^ len;
+    unsigned i = 0;
+    while (len >= 4) {
+        unsigned k = data[i + 0] & 0xFF;
+        k |= (data[i + 1] & 0xFF) << 8;
+        k |= (data[i + 2] & 0xFF) << 16;
+        k |= (data[i + 3] & 0xFF) << 24;
+
+        k *= m;
+        k ^= k >> r;
+        k *= m;
+
+        h *= m;
+        h ^= k;
+
+        i += 4;
+        len -= 4;
+    }
+
+    switch (len) {
+        case 3:
+            h ^= (data[i + 2] & 0xFF) << 16;
+                    __attribute__((__fallthrough__));
+        case 2:
+            h ^= (data[i + 1] & 0xFF) << 8;
+                    __attribute__((__fallthrough__));
+        case 1:
+            h ^= (data[i + 0] & 0xFF);
+            h *= m;
+                    __attribute__((__fallthrough__));
+        default: // do nothing
+            ;
+    }
+
+    h ^= h >> 13;
+    h *= m;
+    h ^= h >> 15;
+
+    key->hash = h;
+}
+
+CxHashKey cx_hash_key_str(char const *str) {
+    CxHashKey key;
+    key.data = str;
+    key.len = str == NULL ? 0 : strlen(str);
+    cx_hash_murmur(&key);
+    return key;
+}
+
+CxHashKey cx_hash_key_bytes(
+        unsigned char const *bytes,
+        size_t len
+) {
+    CxHashKey key;
+    key.data = bytes;
+    key.len = len;
+    cx_hash_murmur(&key);
+    return key;
+}
+
+CxHashKey cx_hash_key(
+        void const *obj,
+        size_t len
+) {
+    CxHashKey key;
+    key.data = obj;
+    key.len = len;
+    cx_hash_murmur(&key);
+    return key;
+}