[wasm] Add UTF-8 validation

src/wasm/utf8.h

+// Copyright 2016 the V8 project authors. All rights reserved.

[titzer, 2016/05/12 08:29:14]

I think we should put this in src/base, since it's not WASM-specific, though it
is only used in WASM.

[Clemens Hammacher, 2016/05/12 11:21:41]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_WASM_UNICODE_H_
+#define V8_WASM_UNICODE_H_
+
+#include <stdint.h>
+
+// UTF8 validation is currently only needed for WASM, so we add this utility
+// here.
+
+namespace v8 {
+namespace internal {
+namespace wasm {
+
+// Check if byte buffer contains a valid UTF8-encoded string.
+// Returns true if multi-byte decoding succeeded and all decoded characters are
+// valid character codepoints. Returns false otherwise.
+bool IsValidUtf8(const uint8_t *buf, int32_t len);
+
+}  // namespace wasm
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_WASM_UNICODE_H_