diff --git a/dix/resource.c b/dix/resource.c
index 5691b1608..9714061b8 100644
--- a/dix/resource.c
+++ b/dix/resource.c
@@ -636,25 +636,32 @@ InitClientResources(ClientPtr client)
     return TRUE;
 }
 
+int
+HashResourceID(XID id, int numBits)
+{
+    id &= RESOURCE_ID_MASK;
+    switch (numBits)
+    {
+        case 6:
+            return ((int)(0x03F & (id ^ (id>>6) ^ (id>>12))));
+        case 7:
+            return ((int)(0x07F & (id ^ (id>>7) ^ (id>>13))));
+        case 8:
+            return ((int)(0x0FF & (id ^ (id>>8) ^ (id>>16))));
+        case 9:
+            return ((int)(0x1FF & (id ^ (id>>9))));
+        case 10:
+            return ((int)(0x3FF & (id ^ (id>>10))));
+        case 11:
+            return ((int)(0x7FF & (id ^ (id>>11))));
+    }
+    return -1;
+}
+
 static int
 Hash(int client, XID id)
 {
-    id &= RESOURCE_ID_MASK;
-    switch (clientTable[client].hashsize) {
-    case 6:
-        return ((int) (0x03F & (id ^ (id >> 6) ^ (id >> 12))));
-    case 7:
-        return ((int) (0x07F & (id ^ (id >> 7) ^ (id >> 13))));
-    case 8:
-        return ((int) (0x0FF & (id ^ (id >> 8) ^ (id >> 16))));
-    case 9:
-        return ((int) (0x1FF & (id ^ (id >> 9))));
-    case 10:
-        return ((int) (0x3FF & (id ^ (id >> 10))));
-    case 11:
-        return ((int) (0x7FF & (id ^ (id >> 11))));
-    }
-    return -1;
+    return HashResourceID(id, clientTable[client].hashsize);
 }
 
 static XID
diff --git a/include/resource.h b/include/resource.h
index 663fac4f6..e8f263705 100644
--- a/include/resource.h
+++ b/include/resource.h
@@ -272,4 +272,15 @@ extern _X_EXPORT unsigned int GetXIDList(ClientPtr /*client */ ,
 extern _X_EXPORT RESTYPE lastResourceType;
 extern _X_EXPORT RESTYPE TypeMask;
 
-#endif                          /* RESOURCE_H */
+/** @brief A hashing function to be used for hashing resource IDs
+
+    @param id The resource ID to hash
+    @param numBits The number of bits in the resulting hash
+
+    @note This function can only handle INITHASHSIZE..MAXHASHSIZE bit
+    hashes and will return -1 if numBits is not within those bounds.
+*/
+extern _X_EXPORT int HashResourceID(XID id,
+                                    int numBits);
+
+#endif /* RESOURCE_H */