Clean up IFX_BidiChar

- Replace IFX_BidiChar with just CFX_BidiChar
- Document implementation
- Change out parameters to pointers
- Remove dead code
- Add an enum for bidi directions
- Move several externs to a header
- Add unit tests

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1197643002 .

1 files changed, 66 insertions, 0 deletions

diff --git a/core/src/fxcrt/fx_bidi.cpp b/core/src/fxcrt/fx_bidi.cpp
new file mode 100644
index 0000000000..0310fa0e94
--- /dev/null
+++ b/core/src/fxcrt/fx_bidi.cpp
@@ -0,0 +1,66 @@
+// 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.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#include "../../include/fxcrt/fx_bidi.h"
+#include "../../include/fxcrt/fx_ucd.h"
+
+CFX_BidiChar::CFX_BidiChar()
+    : m_iCurStart(0),
+      m_iCurCount(0),
+      m_CurBidi(NEUTRAL),
+      m_iLastStart(0),
+      m_iLastCount(0),
+      m_LastBidi(NEUTRAL) {
+}
+
+CFX_BidiChar::~CFX_BidiChar() {
+}
+
+bool CFX_BidiChar::AppendChar(FX_WCHAR wch) {
+  FX_DWORD dwProps = FX_GetUnicodeProperties(wch);
+  int32_t iBidiCls = (dwProps & FX_BIDICLASSBITSMASK) >> FX_BIDICLASSBITS;
+  Direction bidi = NEUTRAL;
+  switch (iBidiCls) {
+    case FX_BIDICLASS_L:
+    case FX_BIDICLASS_AN:
+    case FX_BIDICLASS_EN:
+      bidi = LEFT;
+      break;
+    case FX_BIDICLASS_R:
+    case FX_BIDICLASS_AL:
+      bidi = RIGHT;
+      break;
+  }
+
+  bool bRet = (bidi != m_CurBidi);
+  if (bRet) {
+    SaveCurrentStateToLastState();
+    m_CurBidi = bidi;
+  }
+  m_iCurCount++;
+  return bRet;
+}
+
+bool CFX_BidiChar::EndChar() {
+  SaveCurrentStateToLastState();
+  return m_iLastCount > 0;
+}
+
+CFX_BidiChar::Direction CFX_BidiChar::GetBidiInfo(int32_t* iStart,
+                                                  int32_t* iCount) const {
+  if (iStart)
+    *iStart = m_iLastStart;
+  if (iCount)
+    *iCount = m_iLastCount;
+  return m_LastBidi;
+}
+
+void CFX_BidiChar::SaveCurrentStateToLastState() {
+  m_LastBidi = m_CurBidi;
+  m_iLastStart = m_iCurStart;
+  m_iCurStart = m_iCurCount;
+  m_iLastCount = m_iCurCount - m_iLastStart;
+}