entity per world

Game/Entity/Entity.cpp

@@ -21,6 +21,48 @@ internal void serialize(Archive& ar, uint16 /*version*/, Entity& entity)
     SERIALIZE(ar, position, entity.position);
 }
 
+String format_entity_id(NonNullPtr<Arena> arena, EntityID entity_id)
+{
+    // Format:
+    // U = UserID
+    // LC = Local Entity Counter
+    // UU_LCLCLCLCLCLCLC
+    uint8  user_id = get_user_id(entity_id);
+    uint64 counter = get_local_counter(entity_id);
+
+    constexpr size_t kBufferSize = 18;
+    char*            buffer      = ArenaPushArray<char>(arena, kBufferSize);
+    Assert(buffer);
+
+    juliet_snprintf(buffer, kBufferSize, "%02X_%014llX", (unsigned int)user_id, counter);
+    return { buffer, kBufferSize - 1 };
+}
+
+bool parse_entity_id(String str, EntityID& out_id)
+{
+    bool result = false;
+    out_id      = kInvalid_entity_id;
+
+    if (!(str.Size != 17 || str.Str == nullptr || str.Str[2] != '_'))
+    {
+        char  user_hex[3]{ str.Str[0], str.Str[1], '\0' };
+        char* end     = user_hex;
+        uint8 user_id = strtoul(user_hex, &end, 16);
+        if (end != user_hex && user_id != kInvalid_user_id)
+        {
+            char* counter_hex = str.Str + 3;
+            end               = counter_hex;
+            uint64 counter    = strtoull(counter_hex, &end, 16);
+            if (end != counter_hex && counter < kEntityID_user_id_mask)
+            {
+                out_id = make_entity_id(user_id, counter);
+                result = true;
+            }
+        }
+    }
+    return result;
+}
+
 const Class* resolve_entity_class(uint8 kind, uint32 crc)
 {
     Assert(kind <= ENTITY(Count));