Merge pull request #6203 from livecodeali/feature-proper_list_to_carray

livecodeali · web-flow · commit e3ac04084045 · 2017-12-13T20:55:23.000Z
[[ FFI ]] Add ability to convert proper list to c-array
diff --git a/libfoundation/include/foundation.h b/libfoundation/include/foundation.h
@@ -3391,6 +3391,12 @@ MC_DLLEXPORT bool MCProperListCreate(const MCValueRef *values, uindex_t length,
 // foreign value is created (MCForeignValueRef).
 MC_DLLEXPORT bool MCProperListCreateWithForeignValues(MCTypeInfoRef type, const void *values, uindex_t value_count, MCProperListRef& r_list);
 
+// Create a c-array of foreign values from the given list. The original list is
+// not released. Ownership of the foreign value array is passed to the caller.
+// p_typeinfo must be a foreign typeinfo. If any value in the list is not of the
+// given type, or cannot be exported as that type, this returns false.
+MC_DLLEXPORT bool MCProperListConvertToForeignValues(MCProperListRef list, MCTypeInfoRef p_typeinfo, void*& r_values_ptr, uindex_t& r_values_count);
+    
 // Create an empty mutable list.
 MC_DLLEXPORT bool MCProperListCreateMutable(MCProperListRef& r_list);
 
diff --git a/libfoundation/src/foundation-proper-list.cpp b/libfoundation/src/foundation-proper-list.cpp
@@ -127,6 +127,50 @@ bool MCProperListCreateWithForeignValues(MCTypeInfoRef p_typeinfo, const void *p
     return true;
 }
 
+MC_DLLEXPORT_DEF
+bool MCProperListConvertToForeignValues(MCProperListRef self, MCTypeInfoRef p_typeinfo, void*& r_values_ptr, uindex_t& r_values_count)
+{
+    __MCAssertIsForeignTypeInfo(p_typeinfo);
+    
+    const MCForeignTypeDescriptor *t_descriptor =
+    MCForeignTypeInfoGetDescriptor(p_typeinfo);
+    
+    uindex_t t_values_count = MCProperListGetLength(self);
+    void *t_values = nullptr;
+    if (!MCMemoryNew(t_values_count * t_descriptor->size, t_values))
+    {
+        return false;
+    }
+    
+    byte_t *t_values_ptr = (byte_t*)t_values;
+    for(uindex_t t_index = 0; t_index < t_values_count; t_index++)
+    {
+        MCValueRef t_value = MCProperListFetchElementAtIndex(self, t_index);
+        if (MCValueGetTypeInfo(t_value) == p_typeinfo)
+        {
+            MCMemoryCopy(t_values_ptr, MCForeignValueGetContentsPtr(t_value), t_descriptor->size);
+        }
+        else if (MCValueGetTypeInfo(t_value) == t_descriptor->bridgetype)
+        {
+            if (!t_descriptor->doexport(t_descriptor, t_value, false, t_values_ptr))
+            {
+                MCMemoryDelete(t_values);
+                return false;
+            }
+        }
+        else
+        {
+            MCMemoryDelete(t_values);
+            return false;
+        }
+        t_values_ptr += t_descriptor->size;
+    }
+    
+    r_values_ptr = t_values;
+    r_values_count = t_values_count;
+    
+    return true;
+}
 
 MC_DLLEXPORT_DEF
 bool MCProperListCreateMutable(MCProperListRef& r_list)
diff --git a/tests/lcb/vm/foreign-invoke.lcb b/tests/lcb/vm/foreign-invoke.lcb
@@ -91,4 +91,47 @@ end handler
 
 --------
 
+foreign handler MCProperListConvertToForeignValues(in pList as List, in pTypeInfo as Pointer, \
+   out rCArray as Pointer, out rCount as LCUIndex) returns CBool binds to "<builtin>"
+foreign handler MCAggregateTypeInfo(in pBinding as String, out rTypeInfo as Pointer) returns CBool binds to "<builtin>"
+foreign handler MCValueRelease(in pValue as Pointer) returns nothing binds to "<builtin>"
+foreign handler MCMemoryDelete(in pBlock as Pointer) returns nothing binds to "<builtin>"
+
+unsafe handler CreateCArray(in pList as List, in pAggregateBinding as String, out rPointer as Pointer, out rCount as Integer) returns Boolean
+   variable tCArray as Pointer
+   variable tCount as Integer
+   variable tTypeInfo as Pointer
+   if not MCAggregateTypeInfo(pAggregateBinding, tTypeInfo) then
+      return false
+   end if
+
+   variable tSuccess as Boolean
+   put MCProperListConvertToForeignValues(pList, tTypeInfo, tCArray, tCount) into tSuccess
+
+   MCValueRelease(tTypeInfo)
+   if not tSuccess then
+      return false
+   end if
+
+   put tCArray into rPointer
+   put tCount into rCount
+   return true
+end handler
+
+-- Create a c-array of structs and delete it
+public handler TestProperListToCArray()
+	variable tList as List
+	put [[true, true, true], [false, false, false]] into tList
+    variable tArray as Pointer
+    variable tCount as Integer
+    unsafe
+		test "create c-array of structs" when \
+			CreateCArray(tList, "aaa", tArray, tCount)
+		
+		test "c-array has correct length" when tCount is 2
+	
+		-- Hopefully this would crash if there was a memory issue
+		MCMemoryDelete(tArray)
+	end unsafe
+end handler
 end module
