1 files changed, 81 insertions, 0 deletions
diff --git a/core/fxcrt/fx_bidi.cpp b/core/fxcrt/fx_bidi.cpp
new file mode 100644
index 0000000000..a7a3ecb295
--- /dev/null
+++ b/core/fxcrt/fx_bidi.cpp
@@ -0,0 +1,81 @@
+// 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 "core/include/fxcrt/fx_bidi.h"
+#include "core/include/fxcrt/fx_ucd.h"
+
+#include <algorithm>
+
+CFX_BidiChar::CFX_BidiChar()
+    : m_CurrentSegment({0, 0, NEUTRAL}), m_LastSegment({0, 0, NEUTRAL}) {}
+
+bool CFX_BidiChar::AppendChar(FX_WCHAR wch) {
+  FX_DWORD dwProps = FX_GetUnicodeProperties(wch);
+  int32_t iBidiCls = (dwProps & FX_BIDICLASSBITSMASK) >> FX_BIDICLASSBITS;
+  Direction direction = NEUTRAL;
+  switch (iBidiCls) {
+    case FX_BIDICLASS_L:
+    case FX_BIDICLASS_AN:
+    case FX_BIDICLASS_EN:
+      direction = LEFT;
+      break;
+    case FX_BIDICLASS_R:
+    case FX_BIDICLASS_AL:
+      direction = RIGHT;
+      break;
+  }
+
+  bool bChangeDirection = (direction != m_CurrentSegment.direction);
+  if (bChangeDirection)
+    StartNewSegment(direction);
+
+  m_CurrentSegment.count++;
+  return bChangeDirection;
+}
+
+bool CFX_BidiChar::EndChar() {
+  StartNewSegment(NEUTRAL);
+  return m_LastSegment.count > 0;
+}
+
+void CFX_BidiChar::StartNewSegment(CFX_BidiChar::Direction direction) {
+  m_LastSegment = m_CurrentSegment;
+  m_CurrentSegment.start += m_CurrentSegment.count;
+  m_CurrentSegment.count = 0;
+  m_CurrentSegment.direction = direction;
+}
+
+CFX_BidiString::CFX_BidiString(const CFX_WideString& str)
+    : m_Str(str),
+      m_pBidiChar(new CFX_BidiChar),
+      m_eOverallDirection(CFX_BidiChar::LEFT) {
+  for (int i = 0; i < m_Str.GetLength(); ++i) {
+    if (m_pBidiChar->AppendChar(m_Str.GetAt(i)))
+      m_Order.push_back(m_pBidiChar->GetSegmentInfo());
+  }
+  if (m_pBidiChar->EndChar())
+    m_Order.push_back(m_pBidiChar->GetSegmentInfo());
+
+  size_t nR2L = std::count_if(m_Order.begin(), m_Order.end(),
+                              [](const CFX_BidiChar::Segment& seg) {
+                                return seg.direction == CFX_BidiChar::RIGHT;
+                              });
+
+  size_t nL2R = std::count_if(m_Order.begin(), m_Order.end(),
+                              [](const CFX_BidiChar::Segment& seg) {
+                                return seg.direction == CFX_BidiChar::LEFT;
+                              });
+
+  if (nR2L > 0 && nR2L >= nL2R)
+    SetOverallDirectionRight();
+}
+
+void CFX_BidiString::SetOverallDirectionRight() {
+  if (m_eOverallDirection != CFX_BidiChar::RIGHT) {
+    std::reverse(m_Order.begin(), m_Order.end());
+    m_eOverallDirection = CFX_BidiChar::RIGHT;
+  }
+}