COM: Add helper for SAFEARRAY creation

Signed-off-by: Simon Rozman <simon@rozman.si>

include/WinStd/COM.h

@@ -34,7 +34,8 @@ namespace winstd
         /// \param[in] msg  Error message
         ///
         com_runtime_error(_In_ error_type num, _In_ const std::string& msg) : num_runtime_error<HRESULT>(num, msg)
-        {}
+        {
+        }
 
         ///
         /// Constructs an exception
@@ -43,7 +44,8 @@ namespace winstd
         /// \param[in] msg  Error message
         ///
         com_runtime_error(_In_ error_type num, _In_opt_z_ const char* msg = nullptr) : num_runtime_error<HRESULT>(num, msg)
-        {}
+        {
+        }
     };
 
     /// @}
@@ -1460,6 +1462,58 @@ namespace winstd
     /// \addtogroup WinStdCOMHelpers
     /// @{
 
+    ///
+    /// Builds SAFEARRAY of uniform data
+    ///
+    /// \param[in] vt       Type of array element
+    /// \param[in] array    Pointer to data
+    /// \param[in] columns  Number of columns. When 1, SafeArrayCreateVector is used; when >1, SafeArrayCreate is used.
+    /// \param[in] rows     Number of rows
+    ///
+    /// \return Returns SAFEARRAY
+    ///
+    inline _Ret_notnull_ LPSAFEARRAY BuildSAFEARRAY(_In_ VARTYPE vt, _In_opt_ LPCVOID array, _In_ ULONG columns, _In_ ULONG rows)
+    {
+        const size_t n = columns * rows;
+        if (!array && n)
+            throw std::invalid_argument("array is NULL");
+
+        safearray sa;
+        if (columns == 1) {
+            // Make vector when one column only.
+            sa = SafeArrayCreateVector(vt, 0, rows);
+        }
+        else {
+            // Make 2-dimensional array when more columns.
+            SAFEARRAYBOUND dim[2] = {
+                { columns, 0 },
+                { rows, 0 }
+            };
+            sa = SafeArrayCreate(vt, 2, dim);
+        }
+        if (!sa)
+            throw std::bad_alloc();
+
+        size_t elem_size;
+        switch (vt) {
+        case VT_UI4:
+        case VT_I4: elem_size = 4; break;
+        case VT_UI2:
+        case VT_I2:
+        case VT_BOOL: elem_size = 2; break;
+        case VT_UI1:
+        case VT_I1: elem_size = 1; break;
+        default: throw std::invalid_argument("unsupported type");
+        };
+
+        {
+            safearray_accessor<void> saa(sa);
+            memcpy(saa.data(), array, elem_size * n);
+        }
+
+        return sa.detach();
+    }
+
     ///
     /// Builds VBARRAY of uniform data
     ///
@@ -1476,7 +1530,7 @@ namespace winstd
         if (!array && n)
             throw std::invalid_argument("array is NULL");
 
-        LPSAFEARRAY sa;
+        safearray sa;
         if (columns == 1) {
             // Make vector when one column only.
             sa = SafeArrayCreateVector(VT_VARIANT, 0, rows);
@@ -1536,7 +1590,7 @@ namespace winstd
 
         VARIANT var;
         V_VT(&var) = VT_ARRAY | VT_VARIANT;
-        V_ARRAY(&var) = sa;
+        V_ARRAY(&var) = sa.detach();
         return var;
     }
 
@@ -1560,7 +1614,7 @@ namespace winstd
         if (!array && rows)
             throw std::invalid_argument("array is NULL");
 
-        LPSAFEARRAY sa;
+        safearray sa;
         if constexpr (columns == 1) {
             // Make vector when one column only.
             sa = SafeArrayCreateVector(VT_VARIANT, 0, rows);
@@ -1590,7 +1644,7 @@ namespace winstd
 
         VARIANT var;
         V_VT(&var) = VT_ARRAY | VT_VARIANT;
-        V_ARRAY(&var) = sa;
+        V_ARRAY(&var) = sa.detach();
         return var;
     }
 
@@ -1614,7 +1668,7 @@ namespace winstd
 
         // Allocate.
         size_t pallete_size = sizeof(RGBQUAD) * bmh.biClrUsed;
-        LPSAFEARRAY sa = SafeArrayCreateVector(VT_UI1, 0, static_cast<ULONG>(sizeof(BITMAPFILEHEADER) + sizeof(bmh) + pallete_size + bmh.biSizeImage));
+        safearray sa = SafeArrayCreateVector(VT_UI1, 0, static_cast<ULONG>(sizeof(BITMAPFILEHEADER) + sizeof(bmh) + pallete_size + bmh.biSizeImage));
         if (!sa)
             throw std::bad_alloc();
 
@@ -1642,7 +1696,7 @@ namespace winstd
 
         VARIANT var;
         V_VT(&var) = VT_ARRAY | VT_UI1;
-        V_ARRAY(&var) = sa;
+        V_ARRAY(&var) = sa.detach();
         return var;
     }