From cc874364b25f7f7a3b199694acc006240068da10 Mon Sep 17 00:00:00 2001
From: Dane Springmeyer <dane@mapbox.com>
Date: Wed, 11 Jun 2014 16:58:58 -0700
Subject: [PATCH] allow external image data - refs #2002

Conflicts:
	include/mapnik/image_data.hpp
	tests/cpp_tests/image_io_test.cpp
---
 include/mapnik/image_data.hpp     | 30 ++++++++++++++++++++++++++----
 tests/cpp_tests/image_io_test.cpp |  8 ++++++++
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/include/mapnik/image_data.hpp b/include/mapnik/image_data.hpp
index b46fa4b7c..d8df2f423 100644
--- a/include/mapnik/image_data.hpp
+++ b/include/mapnik/image_data.hpp
@@ -39,9 +39,10 @@ class ImageData
 public:
     typedef T pixel_type;
 
-    ImageData(int width,int height)
+    ImageData(int width, int height)
         : width_(static_cast<unsigned>(width)),
-          height_(static_cast<unsigned>(height))
+          height_(static_cast<unsigned>(height)),
+          owns_data_(true)
     {
         if (width < 0)
         {
@@ -55,9 +56,26 @@ public:
         if (pData_) std::memset(pData_,0,sizeof(T)*width_*height_);
     }
 
+    ImageData(int width, int height, T * data)
+        : width_(static_cast<unsigned>(width)),
+          height_(static_cast<unsigned>(height)),
+          owns_data_(false),
+          pData_(data)
+    {
+        if (width < 0)
+        {
+            throw std::runtime_error("negative width not allowed for image_data");
+        }
+        if (height < 0)
+        {
+            throw std::runtime_error("negative height not allowed for image_data");
+        }
+    }
+
     ImageData(ImageData<T> const& rhs)
         :width_(rhs.width_),
          height_(rhs.height_),
+         owns_data_(true),
          pData_((rhs.width_!=0 && rhs.height_!=0)?
                 static_cast<T*>(::operator new(sizeof(T)*rhs.width_*rhs.height_)) :0)
     {
@@ -160,14 +178,18 @@ public:
 
     inline ~ImageData()
     {
-        ::operator delete(pData_),pData_=0;
+        if (owns_data_)
+        {
+            ::operator delete(pData_),pData_=0;
+        }
     }
 
 private:
     unsigned width_;
     unsigned height_;
+    bool owns_data_;
     T *pData_;
-    ImageData& operator=(const ImageData&);
+    ImageData& operator=(ImageData const&);
 };
 
 typedef ImageData<unsigned> image_data_32;
diff --git a/tests/cpp_tests/image_io_test.cpp b/tests/cpp_tests/image_io_test.cpp
index bdc4f8967..aae80ede0 100644
--- a/tests/cpp_tests/image_io_test.cpp
+++ b/tests/cpp_tests/image_io_test.cpp
@@ -21,6 +21,14 @@ int main(int argc, char** argv)
     boost::optional<std::string> type;
     try
     {
+        mapnik::image_data_32 im(256,256);
+        unsigned char* bytes = im.getBytes();
+        mapnik::image_data_32 * im_ptr = new mapnik::image_data_32(256,256,(unsigned int *)bytes);
+        unsigned char* same_bytes = im_ptr->getBytes();
+        BOOST_TEST(bytes == same_bytes);
+        delete im_ptr;
+        BOOST_TEST(bytes == same_bytes);
+
         BOOST_TEST(set_working_dir(args));
 
 #if defined(HAVE_JPEG)