From 33607145a6dc7b11c390dc46edd26cad1149c2e6 Mon Sep 17 00:00:00 2001
From: artemp <artem@mapnik.org>
Date: Wed, 3 Dec 2014 10:26:21 +0100
Subject: [PATCH] add image_data_null which is cheap to construct (no mem
 alloc) add default ctor to image_data_any -> image_data_null

---
 include/mapnik/image_data_any.hpp | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/mapnik/image_data_any.hpp b/include/mapnik/image_data_any.hpp
index dec500225..0c6fe0623 100644
--- a/include/mapnik/image_data_any.hpp
+++ b/include/mapnik/image_data_any.hpp
@@ -28,7 +28,15 @@
 
 namespace mapnik {
 
-using image_data_base = util::variant<image_data_32, image_data_8, image_data_16, image_data_float32>;
+struct image_data_null
+{
+    unsigned char const* getBytes() const { return nullptr; }
+    unsigned char* getBytes() { return nullptr;}
+    std::size_t width() const { return 0; }
+    std::size_t height() const { return 0; }
+};
+
+using image_data_base = util::variant<image_data_null, image_data_32, image_data_8, image_data_16, image_data_float32>;
 
 namespace detail {
 
@@ -72,6 +80,8 @@ struct get_height_visitor : util::static_visitor<std::size_t>
 
 struct image_data_any : image_data_base
 {
+    image_data_any() = default;
+
     template <typename T>
     image_data_any(T && data) noexcept
         : image_data_base(std::move(data)) {}