Simplify UTF16LE_Encode and add unittest.

Previously, UTF16LE_Encode take an optional flag to indicate
if the returned byte string has trailing zeros. In fact, no where
needs the flag to be false. So just get rid of it so callers won't
misuse.

The bug is found by https://codereview.chromium.org/837723009

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/860973002

2 files changed, 35 insertions, 10 deletions

diff --git a/core/src/fxcrt/fx_basic_wstring.cpp b/core/src/fxcrt/fx_basic_wstring.cpp
index 0827fb6f34..0945d2f1c5 100644
--- a/core/src/fxcrt/fx_basic_wstring.cpp
+++ b/core/src/fxcrt/fx_basic_wstring.cpp
@@ -323,25 +323,21 @@ CFX_ByteString CFX_WideString::UTF8Encode() const
 {
     return FX_UTF8Encode(*this);
 }
-CFX_ByteString CFX_WideString::UTF16LE_Encode(FX_BOOL bTerminate) const
+CFX_ByteString CFX_WideString::UTF16LE_Encode() const
 {
     if (m_pData == NULL) {
-        return bTerminate ? CFX_ByteString(FX_BSTRC("\0\0")) : CFX_ByteString();
+        return CFX_ByteString(FX_BSTRC("\0\0"));
     }
     int len = m_pData->m_nDataLength;
     CFX_ByteString result;
-    FX_LPSTR buffer = result.GetBuffer(len * 2 + (bTerminate ? 2 : 0));
+    FX_LPSTR buffer = result.GetBuffer(len * 2 + 2);
     for (int i = 0; i < len; i ++) {
         buffer[i * 2] = m_pData->m_String[i] & 0xff;
         buffer[i * 2 + 1] = m_pData->m_String[i] >> 8;
     }
-    if (bTerminate) {
-        buffer[len * 2] = 0;
-        buffer[len * 2 + 1] = 0;
-        result.ReleaseBuffer(len * 2 + 2);
-    } else {
-        result.ReleaseBuffer(len * 2);
-    }
+    buffer[len * 2] = 0;
+    buffer[len * 2 + 1] = 0;
+    result.ReleaseBuffer(len * 2 + 2);
     return result;
 }
 void CFX_WideString::ConvertFrom(const CFX_ByteString& str, CFX_CharMap* pCharMap)
diff --git a/core/src/fxcrt/fx_basic_wstring_unittest.cpp b/core/src/fxcrt/fx_basic_wstring_unittest.cpp
new file mode 100644
index 0000000000..c6e5c2f3d0
--- /dev/null
+++ b/core/src/fxcrt/fx_basic_wstring_unittest.cpp
@@ -0,0 +1,29 @@
+// Copyright 2014 PDFium Authors. All rights reserved.

+// Use of this source code is governed by a BSD-style license that can be

+// found in the LICENSE file.

+

+#include "testing/gtest/include/gtest/gtest.h"

+#include "../../../testing/fx_string_testhelpers.h"

+#include "../../include/fxcrt/fx_basic.h"

+

+#define ByteStringLiteral(str) CFX_ByteString(FX_BSTRC(str))

+

+TEST(fxcrt, WideStringUTF16LE_Encode) {

+  struct UTF16LEEncodeCase {

+    CFX_WideString ws;

+    CFX_ByteString bs;

+  } utf16le_encode_cases[] = {

+    { L"", ByteStringLiteral("\0\0") },

+    { L"abc", ByteStringLiteral("a\0b\0c\0\0\0") },

+    { L"abcdef", ByteStringLiteral("a\0b\0c\0d\0e\0f\0\0\0") },

+    { L"abc\0def", ByteStringLiteral("a\0b\0c\0\0\0") },

+    { L"\xaabb\xccdd", ByteStringLiteral("\xbb\xaa\xdd\xcc\0\0") },

+    { L"\x3132\x6162", ByteStringLiteral("\x32\x31\x62\x61\0\0") },

+  };

+

+  for (size_t i = 0; i < FX_ArraySize(utf16le_encode_cases); ++i) {

+    EXPECT_EQ(utf16le_encode_cases[i].bs,

+        utf16le_encode_cases[i].ws.UTF16LE_Encode())

+        << " for case number " << i;

+  }

+}