Add a unit test for odd-sized small structs (for google#8117) (google…

…#8363) * add an odd sized test * formatting --------- Co-authored-by: Derek Bailey <[email protected]>
jochenparm · Oct 29, 2024 · ed3f7f5 · ed3f7f5
1 parent 3e37e6c
commit ed3f7f5
Show file tree

Hide file tree

Showing 2 changed files with 32 additions and 16 deletions.
diff --git a/tests/alignment_test.cpp b/tests/alignment_test.cpp
@@ -34,15 +34,18 @@ void AlignmentTest() {
 
   // creating 5 structs with 2 bytes each
   // 10 bytes in total for Vector data is needed
-  std::vector<JustSmallStruct> small_vector = {
-    { 2, 1 }, { 3, 1 }, { 4, 1 }
-  };
+  std::vector<EvenSmallStruct> even_vector = { { 2, 1 }, { 3, 1 }, { 4, 1 } };
+  std::vector<OddSmallStruct> odd_vector = { { 6, 5, 4 },
+                                             { 9, 8, 7 },
+                                             { 1, 2, 3 } };
   // CreateVectorOfStructs is used in the generated CreateSmallStructsDirect()
   // method, but we test it directly
-  Offset<Vector<const JustSmallStruct *>> small_structs_offset =
-      builder.CreateVectorOfStructs<JustSmallStruct>(small_vector);
+  Offset<Vector<const EvenSmallStruct *>> even_structs_offset =
+      builder.CreateVectorOfStructs<EvenSmallStruct>(even_vector);
+  Offset<Vector<const OddSmallStruct *>> odd_structs_offset =
+      builder.CreateVectorOfStructs<OddSmallStruct>(odd_vector);
   Offset<SmallStructs> small_structs_root =
-      CreateSmallStructs(builder, small_structs_offset);
+      CreateSmallStructs(builder, even_structs_offset, odd_structs_offset);
 
   builder.Finish(small_structs_root);
 
@@ -62,13 +65,17 @@ void AlignmentTest() {
   auto root_msg =
       flatbuffers::GetRoot<SmallStructs>(builder.GetBufferPointer());
 
-  TEST_EQ(root_msg->small_structs()->size(), small_vector.size());
-  for (flatbuffers::uoffset_t i = 0; i < root_msg->small_structs()->size();
+  TEST_EQ(root_msg->even_structs()->size(), even_vector.size());
+  for (flatbuffers::uoffset_t i = 0; i < root_msg->even_structs()->size();
        ++i) {
-    TEST_EQ(small_vector[i].var_0(),
-            root_msg->small_structs()->Get(i)->var_0());
-    TEST_EQ(small_vector[i].var_1(),
-            root_msg->small_structs()->Get(i)->var_1());
+    TEST_EQ(even_vector[i].var_0(), root_msg->even_structs()->Get(i)->var_0());
+    TEST_EQ(even_vector[i].var_1(), root_msg->even_structs()->Get(i)->var_1());
+  }
+
+  TEST_EQ(root_msg->odd_structs()->size(), even_vector.size());
+  for (flatbuffers::uoffset_t i = 0; i < root_msg->odd_structs()->size(); ++i) {
+    TEST_EQ(odd_vector[i].var_0(), root_msg->odd_structs()->Get(i)->var_0());
+    TEST_EQ(odd_vector[i].var_1(), root_msg->odd_structs()->Get(i)->var_1());
   }
 }
 

diff --git a/tests/alignment_test.fbs b/tests/alignment_test.fbs
@@ -21,15 +21,24 @@ table BadAlignmentRoot {
   small: [BadAlignmentSmall];
 }
 
-// sizeof(JustSmallStruct) == 2
-// alignof(JustSmallStruct) == 1
-struct JustSmallStruct {
+// sizeof(EvenSmallStruct) == 2
+// alignof(EvenSmallStruct) == 1
+struct EvenSmallStruct {
   var_0: uint8;
   var_1: uint8;
 }
 
+// sizeof(OddSmallStruct) == 3
+// alignof(OddSmallStruct) == 1
+struct OddSmallStruct {
+  var_0: uint8;
+  var_1: uint8;
+  var_2: uint8;
+}
+
 table SmallStructs {
-  small_structs: [JustSmallStruct];
+  even_structs: [EvenSmallStruct];
+  odd_structs: [OddSmallStruct];
 }
 
 root_type SmallStructs;