AAPT2: Respect format attribute of <item> tag
An <item> is a general tag that can override certain behavior. For
instance, this is allowed:
<item name="foo" type="integer" format="float">0.4</item>
Even though without the format attribute, this would be illegal.
Change-Id: I8133ce59e14719a70d7476a1464c3f564c435289
diff --git a/tools/aapt2/util/TypeTraits.h b/tools/aapt2/util/TypeTraits.h
new file mode 100644
index 0000000..76c13d6
--- /dev/null
+++ b/tools/aapt2/util/TypeTraits.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef AAPT_UTIL_TYPETRAITS_H
+#define AAPT_UTIL_TYPETRAITS_H
+
+#include <type_traits>
+
+namespace aapt {
+
+#define DEFINE_HAS_BINARY_OP_TRAIT(name, op) \
+ template <typename T, typename U> \
+ struct name { \
+ template <typename V, typename W> \
+ static constexpr decltype(std::declval<V>() op std::declval<W>(), bool()) test(int) { \
+ return true; \
+ } \
+ template <typename V, typename W> \
+ static constexpr bool test(...) { \
+ return false; \
+ } \
+ static constexpr bool value = test<T, U>(int()); \
+}
+
+DEFINE_HAS_BINARY_OP_TRAIT(has_eq_op, ==);
+DEFINE_HAS_BINARY_OP_TRAIT(has_lt_op, <);
+
+/**
+ * Type trait that checks if two types can be equated (==) and compared (<).
+ */
+template <typename T, typename U>
+struct is_comparable {
+ static constexpr bool value = has_eq_op<T, U>::value && has_lt_op<T, U>::value;
+};
+
+} // namespace aapt
+
+#endif /* AAPT_UTIL_TYPETRAITS_H */