Improved cuda_data_ptr.

dlib/dnn/cuda_data_ptr.cpp

@@ -37,28 +37,52 @@ namespace dlib
 
         void memcpy(
             void* dest,
-            const cuda_data_void_ptr& src
+            const cuda_data_void_ptr& src,
+            const size_t num
         )
         {
+            DLIB_ASSERT(num <= src.size());
             if (src.size() != 0)
             {
-                CHECK_CUDA(cudaMemcpy(dest, src.data(),  src.size(), cudaMemcpyDefault));
+                CHECK_CUDA(cudaMemcpy(dest, src.data(),  num, cudaMemcpyDefault));
             }
         }
 
     // ------------------------------------------------------------------------------------
 
         void memcpy(
-            cuda_data_void_ptr& dest, 
-            const void* src
+            void* dest,
+            const cuda_data_void_ptr& src
         )
         {
+            memcpy(dest, src, src.size());
+        }
+
+    // ------------------------------------------------------------------------------------
+
+        void memcpy(
+            cuda_data_void_ptr dest, 
+            const void* src,
+            const size_t num
+        )
+        {
+            DLIB_ASSERT(num <= dest.size());
             if (dest.size() != 0)
             {
-                CHECK_CUDA(cudaMemcpy(dest.data(), src, dest.size(), cudaMemcpyDefault));
+                CHECK_CUDA(cudaMemcpy(dest.data(), src, num, cudaMemcpyDefault));
             }
         }
 
+    // ------------------------------------------------------------------------------------
+
+        void memcpy(
+            cuda_data_void_ptr dest, 
+            const void* src
+        )
+        {
+            memcpy(dest,src,dest.size());
+        }
+
     // ------------------------------------------------------------------------------------
 
         class cudnn_device_buffer

dlib/dnn/cuda_data_ptr.h

@@ -7,6 +7,7 @@
 
 #include <memory>
 #include <vector>
+#include "../assert.h"
 
 namespace dlib
 {
@@ -45,12 +46,29 @@ namespace dlib
                     - returns the length of this buffer, in bytes.
             !*/
 
+            cuda_data_void_ptr operator+ (size_t offset) const 
+            /*!
+                requires
+                    - offset < size()
+                ensures
+                    - returns a pointer that is offset by the given amount.
+            !*/
+            { 
+                DLIB_CASSERT(offset < num);
+                cuda_data_void_ptr temp;
+                temp.num = num-offset;
+                temp.pdata = std::shared_ptr<void>(pdata, ((char*)pdata.get())+offset);
+                return temp;
+            }
+
         private:
 
             size_t num = 0;
             std::shared_ptr<void> pdata;
         };
 
+        inline cuda_data_void_ptr operator+(size_t offset, const cuda_data_void_ptr& rhs) { return rhs+offset; }
+
     // ------------------------------------------------------------------------------------
 
         void memcpy(
@@ -62,12 +80,27 @@ namespace dlib
                 - dest == a pointer to at least src.size() bytes on the host machine.
             ensures
                 - copies the GPU data from src into dest.
+                - This routine is equivalent to performing: memcpy(dest,src,src.size())
+        !*/
+
+        void memcpy(
+            void* dest,
+            const cuda_data_void_ptr& src,
+            const size_t num
+        );
+        /*!
+            requires
+                - dest == a pointer to at least num bytes on the host machine.
+                - num <= src.size()
+            ensures
+                - copies the GPU data from src into dest.  Copies only the first num bytes
+                  of src to dest.
         !*/
 
     // ------------------------------------------------------------------------------------
 
         void memcpy(
-            cuda_data_void_ptr& dest, 
+            cuda_data_void_ptr dest, 
             const void* src
         );
         /*!
@@ -75,6 +108,21 @@ namespace dlib
                 - dest == a pointer to at least src.size() bytes on the host machine.
             ensures
                 - copies the host data from src to the GPU memory buffer dest.
+                - This routine is equivalent to performing: memcpy(dest,src,dest.size())
+        !*/
+
+        void memcpy(
+            cuda_data_void_ptr dest, 
+            const void* src,
+            const size_t num
+        );
+        /*!
+            requires
+                - dest == a pointer to at least num bytes on the host machine.
+                - num <= dest.size()
+            ensures
+                - copies the host data from src to the GPU memory buffer dest.  Copies only
+                  the first num bytes of src to dest.
         !*/
 
     // ------------------------------------------------------------------------------------