Fixed a bug that caused the matrix to throw an error during some assignment

statements when used inside a matlab mex file.

dlib/matrix/matrix.h

@@ -1114,14 +1114,42 @@ namespace dlib
 #ifdef DLIB_HAS_RVALUE_REFERENCES
         matrix(matrix&& item)
         {
+        #ifdef MATLAB_MEX_FILE
+            // You can't move memory around when compiled in a matlab mex file and the
+            // different locations have different persistence settings.
+            if (data._private_is_persistent() == item.data._private_is_persistent())
+            {
+                swap(item);
+            }
+            else
+            {
+                data.set_size(item.nr(),item.nc());
+                matrix_assign(*this, item);
+            }
+        #else
             swap(item);
+        #endif
         }
 
         matrix& operator= (
             matrix&& rhs
         )
         {
+        #ifdef MATLAB_MEX_FILE
+            // You can't move memory around when compiled in a matlab mex file and the
+            // different locations have different persistence settings.
+            if (data._private_is_persistent() == rhs.data._private_is_persistent())
+            {
+                swap(rhs);
+            }
+            else
+            {
+                data.set_size(rhs.nr(),rhs.nc());
+                matrix_assign(*this, rhs);
+            }
+        #else
             swap(rhs);
+        #endif
             return *this;
         }
 #endif

dlib/matrix/matrix_data_layout.h

@@ -188,6 +188,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
         private:
@@ -257,6 +258,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
         private:
@@ -338,6 +340,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
         private:
@@ -422,6 +425,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
         private:
@@ -508,6 +512,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
         private:
             T* data;
@@ -630,6 +635,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
         private:
@@ -699,6 +705,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
         private:
@@ -780,6 +787,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
         private:
@@ -864,6 +872,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
         private:
@@ -930,6 +939,7 @@ namespace dlib
             void _private_set_mxArray ( mxArray* ) { DLIB_CASSERT(false, "This function should never be called."); }
             mxArray* _private_release_mxArray(){DLIB_CASSERT(false, "This function should never be called."); }
             void _private_mark_non_persistent() {DLIB_CASSERT(false, "This function should never be called."); } 
+            bool _private_is_persistent()       {DLIB_CASSERT(false, "This function should never be called."); }
 #endif
 
             long nr (
@@ -1031,6 +1041,10 @@ namespace dlib
                 DLIB_CASSERT(mem == 0,"You can't convert a persistent matlab array to non-persistent.");
                 make_persistent = false;
             }
+            bool _private_is_persistent()
+            {
+                return make_persistent;
+            }
 
             void swap(
                 layout& item
@@ -1153,6 +1167,10 @@ namespace dlib
                 DLIB_CASSERT(mem == 0,"You can't convert a persistent matlab array to non-persistent.");
                 make_persistent = false;
             }
+            bool _private_is_persistent()
+            {
+                return make_persistent;
+            }
 
             void swap(
                 layout& item