Allow zero-length arrays as the last element in a FFI::Struct

2 files changed, 4 insertions, 3 deletions

diff --git a/ext/ffi_c/Struct.c b/ext/ffi_c/Struct.c
index c18c566..5fb3a82 100644
--- a/ext/ffi_c/Struct.c
+++ b/ext/ffi_c/Struct.c
@@ -493,7 +493,7 @@ inline_array_size(VALUE self)
 static int
 inline_array_offset(InlineArray* array, int index)
 {
-    if (index < 0 || index >= array->length) {
+    if (index < 0 || (index >= array->length && array->length > 0)) {
         rb_raise(rb_eIndexError, "index %d out of bounds", index);
     }
 
diff --git a/ext/ffi_c/StructLayout.c b/ext/ffi_c/StructLayout.c
index 7a431a7..1561830 100644
--- a/ext/ffi_c/StructLayout.c
+++ b/ext/ffi_c/StructLayout.c
@@ -388,7 +388,7 @@ struct_layout_initialize(VALUE self, VALUE fields, VALUE size, VALUE align)
         }
 
         ftype = field->type->ffiType;
-        if (ftype->size == 0) {
+        if (ftype->size == 0 && i < ((int) layout->fieldCount - 1)) {
             rb_raise(rb_eTypeError, "type of field %d has zero size", i);
         }
 
@@ -396,7 +396,8 @@ struct_layout_initialize(VALUE self, VALUE fields, VALUE size, VALUE align)
             field->referenceIndex = layout->referenceFieldCount++;
         }
 
-        layout->ffiTypes[i] = ftype;
+
+        layout->ffiTypes[i] = ftype->size > 0 ? ftype : NULL;
         st_insert(layout->fieldSymbolTable, rbName, rbField);
         rb_hash_aset(layout->rbFieldMap, rbName, rbField);
         rb_ary_push(layout->rbFields, rbField);