1 files changed, 75 insertions, 0 deletions
diff --git a/src/support/safe_integer.cpp b/src/support/safe_integer.cpp
new file mode 100644
index 000000000..dbe62ca52
--- /dev/null
+++ b/src/support/safe_integer.cpp
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2016 WebAssembly Community Group participants
+ *
+ * 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.
+ */
+
+#include <cassert>
+#include <cmath>
+#include <limits>
+
+#include "support/safe_integer.h"
+
+using namespace wasm;
+
+bool wasm::isInteger(double x) { return fmod(x, 1) == 0; }
+
+bool wasm::isUInteger32(double x) {
+  return isInteger(x) && x >= 0 && x <= std::numeric_limits<uint32_t>::max();
+}
+
+bool wasm::isSInteger32(double x) {
+  return isInteger(x) && x >= std::numeric_limits<int32_t>::min() &&
+         x <= std::numeric_limits<int32_t>::max();
+}
+
+uint32_t wasm::toUInteger32(double x) {
+  assert(isUInteger32(x));
+  return x < std::numeric_limits<uint32_t>::max()
+             ? x
+             : std::numeric_limits<uint32_t>::max();
+}
+
+int32_t wasm::toSInteger32(double x) {
+  assert(isSInteger32(x));
+  return x > std::numeric_limits<int32_t>::min() &&
+                 x < std::numeric_limits<int32_t>::max()
+             ? x
+             : (x < 0 ? std::numeric_limits<int32_t>::min()
+                      : std::numeric_limits<int32_t>::max());
+}
+
+bool wasm::isUInteger64(double x) {
+  return isInteger(x) && x >= 0 && x <= std::numeric_limits<uint64_t>::max();
+}
+
+bool wasm::isSInteger64(double x) {
+  return isInteger(x) && x >= std::numeric_limits<int64_t>::min() &&
+         x <= std::numeric_limits<int64_t>::max();
+}
+
+uint64_t wasm::toUInteger64(double x) {
+  assert(isUInteger64(x));
+  return x < (double)std::numeric_limits<uint64_t>::max()
+             ? (uint64_t)x
+             : std::numeric_limits<uint64_t>::max();
+}
+
+int64_t wasm::toSInteger64(double x) {
+  assert(isSInteger64(x));
+  return x > (double)std::numeric_limits<int64_t>::min() &&
+                 x < (double)std::numeric_limits<int64_t>::max()
+             ? (int64_t)x
+             : (x < 0 ? std::numeric_limits<int64_t>::min()
+                      : std::numeric_limits<int64_t>::max());
+}