diff --git a/core/fxcrt/cfx_widestring.cpp b/core/fxcrt/cfx_widestring.cpp
new file mode 100644
index 0000000..49a62da
--- /dev/null
+++ b/core/fxcrt/cfx_widestring.cpp
@@ -0,0 +1,1044 @@
+// 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/fxcrt/cfx_widestring.h"
+
+#include <stddef.h>
+
+#include <algorithm>
+#include <cctype>
+
+#include "core/fxcrt/cfx_string_pool_template.h"
+#include "core/fxcrt/fx_basic.h"
+#include "core/fxcrt/fx_ext.h"
+#include "third_party/base/numerics/safe_math.h"
+#include "third_party/base/stl_util.h"
+
+template class CFX_StringDataTemplate<wchar_t>;
+template class CFX_StringCTemplate<wchar_t>;
+template class CFX_StringPoolTemplate<CFX_WideString>;
+template struct std::hash<CFX_WideString>;
+
+#define FORCE_ANSI 0x10000
+#define FORCE_UNICODE 0x20000
+#define FORCE_INT64 0x40000
+
+namespace {
+
+#ifndef NDEBUG
+bool IsValidCodePage(uint16_t codepage) {
+  switch (codepage) {
+    case 0:
+    case 932:
+    case 936:
+    case 949:
+    case 950:
+      return true;
+
+    default:
+      return false;
+  }
+}
+#endif
+
+const wchar_t* FX_wcsstr(const wchar_t* haystack,
+                         int haystack_len,
+                         const wchar_t* needle,
+                         int needle_len) {
+  if (needle_len > haystack_len || needle_len == 0) {
+    return nullptr;
+  }
+  const wchar_t* end_ptr = haystack + haystack_len - needle_len;
+  while (haystack <= end_ptr) {
+    int i = 0;
+    while (1) {
+      if (haystack[i] != needle[i]) {
+        break;
+      }
+      i++;
+      if (i == needle_len) {
+        return haystack;
+      }
+    }
+    haystack++;
+  }
+  return nullptr;
+}
+
+FX_STRSIZE GuessSizeForVSWPrintf(const wchar_t* pFormat, va_list argList) {
+  FX_STRSIZE nMaxLen = 0;
+  for (const wchar_t* pStr = pFormat; *pStr != 0; pStr++) {
+    if (*pStr != '%' || *(pStr = pStr + 1) == '%') {
+      ++nMaxLen;
+      continue;
+    }
+    int nItemLen = 0;
+    int nWidth = 0;
+    for (; *pStr != 0; pStr++) {
+      if (*pStr == '#') {
+        nMaxLen += 2;
+      } else if (*pStr == '*') {
+        nWidth = va_arg(argList, int);
+      } else if (*pStr != '-' && *pStr != '+' && *pStr != '0' && *pStr != ' ') {
+        break;
+      }
+    }
+    if (nWidth == 0) {
+      nWidth = FXSYS_wtoi(pStr);
+      while (std::iswdigit(*pStr))
+        ++pStr;
+    }
+    if (nWidth < 0 || nWidth > 128 * 1024)
+      return -1;
+    int nPrecision = 0;
+    if (*pStr == '.') {
+      pStr++;
+      if (*pStr == '*') {
+        nPrecision = va_arg(argList, int);
+        pStr++;
+      } else {
+        nPrecision = FXSYS_wtoi(pStr);
+        while (std::iswdigit(*pStr))
+          ++pStr;
+      }
+    }
+    if (nPrecision < 0 || nPrecision > 128 * 1024)
+      return -1;
+    int nModifier = 0;
+    if (*pStr == L'I' && *(pStr + 1) == L'6' && *(pStr + 2) == L'4') {
+      pStr += 3;
+      nModifier = FORCE_INT64;
+    } else {
+      switch (*pStr) {
+        case 'h':
+          nModifier = FORCE_ANSI;
+          pStr++;
+          break;
+        case 'l':
+          nModifier = FORCE_UNICODE;
+          pStr++;
+          break;
+        case 'F':
+        case 'N':
+        case 'L':
+          pStr++;
+          break;
+      }
+    }
+    switch (*pStr | nModifier) {
+      case 'c':
+      case 'C':
+        nItemLen = 2;
+        va_arg(argList, int);
+        break;
+      case 'c' | FORCE_ANSI:
+      case 'C' | FORCE_ANSI:
+        nItemLen = 2;
+        va_arg(argList, int);
+        break;
+      case 'c' | FORCE_UNICODE:
+      case 'C' | FORCE_UNICODE:
+        nItemLen = 2;
+        va_arg(argList, int);
+        break;
+      case 's': {
+        const wchar_t* pstrNextArg = va_arg(argList, const wchar_t*);
+        if (pstrNextArg) {
+          nItemLen = FXSYS_wcslen(pstrNextArg);
+          if (nItemLen < 1) {
+            nItemLen = 1;
+          }
+        } else {
+          nItemLen = 6;
+        }
+      } break;
+      case 'S': {
+        const char* pstrNextArg = va_arg(argList, const char*);
+        if (pstrNextArg) {
+          nItemLen = FXSYS_strlen(pstrNextArg);
+          if (nItemLen < 1) {
+            nItemLen = 1;
+          }
+        } else {
+          nItemLen = 6;
+        }
+      } break;
+      case 's' | FORCE_ANSI:
+      case 'S' | FORCE_ANSI: {
+        const char* pstrNextArg = va_arg(argList, const char*);
+        if (pstrNextArg) {
+          nItemLen = FXSYS_strlen(pstrNextArg);
+          if (nItemLen < 1) {
+            nItemLen = 1;
+          }
+        } else {
+          nItemLen = 6;
+        }
+      } break;
+      case 's' | FORCE_UNICODE:
+      case 'S' | FORCE_UNICODE: {
+        const wchar_t* pstrNextArg = va_arg(argList, wchar_t*);
+        if (pstrNextArg) {
+          nItemLen = FXSYS_wcslen(pstrNextArg);
+          if (nItemLen < 1) {
+            nItemLen = 1;
+          }
+        } else {
+          nItemLen = 6;
+        }
+      } break;
+    }
+    if (nItemLen != 0) {
+      if (nPrecision != 0 && nItemLen > nPrecision) {
+        nItemLen = nPrecision;
+      }
+      if (nItemLen < nWidth) {
+        nItemLen = nWidth;
+      }
+    } else {
+      switch (*pStr) {
+        case 'd':
+        case 'i':
+        case 'u':
+        case 'x':
+        case 'X':
+        case 'o':
+          if (nModifier & FORCE_INT64) {
+            va_arg(argList, int64_t);
+          } else {
+            va_arg(argList, int);
+          }
+          nItemLen = 32;
+          if (nItemLen < nWidth + nPrecision) {
+            nItemLen = nWidth + nPrecision;
+          }
+          break;
+        case 'a':
+        case 'A':
+        case 'e':
+        case 'E':
+        case 'g':
+        case 'G':
+          va_arg(argList, double);
+          nItemLen = 128;
+          if (nItemLen < nWidth + nPrecision) {
+            nItemLen = nWidth + nPrecision;
+          }
+          break;
+        case 'f':
+          if (nWidth + nPrecision > 100) {
+            nItemLen = nPrecision + nWidth + 128;
+          } else {
+            double f;
+            char pszTemp[256];
+            f = va_arg(argList, double);
+            FXSYS_snprintf(pszTemp, sizeof(pszTemp), "%*.*f", nWidth,
+                           nPrecision + 6, f);
+            nItemLen = FXSYS_strlen(pszTemp);
+          }
+          break;
+        case 'p':
+          va_arg(argList, void*);
+          nItemLen = 32;
+          if (nItemLen < nWidth + nPrecision) {
+            nItemLen = nWidth + nPrecision;
+          }
+          break;
+        case 'n':
+          va_arg(argList, int*);
+          break;
+      }
+    }
+    nMaxLen += nItemLen;
+  }
+  nMaxLen += 32;  // Fudge factor.
+  return nMaxLen;
+}
+
+}  // namespace
+
+static_assert(sizeof(CFX_WideString) <= sizeof(wchar_t*),
+              "Strings must not require more space than pointers");
+
+CFX_WideString::CFX_WideString() {}
+
+CFX_WideString::CFX_WideString(const CFX_WideString& other)
+    : m_pData(other.m_pData) {}
+
+CFX_WideString::CFX_WideString(CFX_WideString&& other) noexcept {
+  m_pData.Swap(other.m_pData);
+}
+
+CFX_WideString::CFX_WideString(const wchar_t* pStr, FX_STRSIZE nLen) {
+  if (nLen < 0)
+    nLen = pStr ? FXSYS_wcslen(pStr) : 0;
+
+  if (nLen)
+    m_pData.Reset(StringData::Create(pStr, nLen));
+}
+
+CFX_WideString::CFX_WideString(wchar_t ch) {
+  m_pData.Reset(StringData::Create(1));
+  m_pData->m_String[0] = ch;
+}
+
+CFX_WideString::CFX_WideString(const wchar_t* ptr)
+    : CFX_WideString(ptr, ptr ? FXSYS_wcslen(ptr) : 0) {}
+
+CFX_WideString::CFX_WideString(const CFX_WideStringC& stringSrc) {
+  if (!stringSrc.IsEmpty()) {
+    m_pData.Reset(StringData::Create(stringSrc.c_str(), stringSrc.GetLength()));
+  }
+}
+
+CFX_WideString::CFX_WideString(const CFX_WideStringC& str1,
+                               const CFX_WideStringC& str2) {
+  int nNewLen = str1.GetLength() + str2.GetLength();
+  if (nNewLen == 0)
+    return;
+
+  m_pData.Reset(StringData::Create(nNewLen));
+  m_pData->CopyContents(str1.c_str(), str1.GetLength());
+  m_pData->CopyContentsAt(str1.GetLength(), str2.c_str(), str2.GetLength());
+}
+
+CFX_WideString::~CFX_WideString() {}
+
+const CFX_WideString& CFX_WideString::operator=(const wchar_t* pStr) {
+  if (!pStr || !pStr[0])
+    clear();
+  else
+    AssignCopy(pStr, FXSYS_wcslen(pStr));
+
+  return *this;
+}
+
+const CFX_WideString& CFX_WideString::operator=(
+    const CFX_WideStringC& stringSrc) {
+  if (stringSrc.IsEmpty())
+    clear();
+  else
+    AssignCopy(stringSrc.c_str(), stringSrc.GetLength());
+
+  return *this;
+}
+
+const CFX_WideString& CFX_WideString::operator=(
+    const CFX_WideString& stringSrc) {
+  if (m_pData != stringSrc.m_pData)
+    m_pData = stringSrc.m_pData;
+
+  return *this;
+}
+
+const CFX_WideString& CFX_WideString::operator+=(const wchar_t* pStr) {
+  if (pStr)
+    Concat(pStr, FXSYS_wcslen(pStr));
+
+  return *this;
+}
+
+const CFX_WideString& CFX_WideString::operator+=(wchar_t ch) {
+  Concat(&ch, 1);
+  return *this;
+}
+
+const CFX_WideString& CFX_WideString::operator+=(const CFX_WideString& str) {
+  if (str.m_pData)
+    Concat(str.m_pData->m_String, str.m_pData->m_nDataLength);
+
+  return *this;
+}
+
+const CFX_WideString& CFX_WideString::operator+=(const CFX_WideStringC& str) {
+  if (!str.IsEmpty())
+    Concat(str.c_str(), str.GetLength());
+
+  return *this;
+}
+
+bool CFX_WideString::operator==(const wchar_t* ptr) const {
+  if (!m_pData)
+    return !ptr || !ptr[0];
+
+  if (!ptr)
+    return m_pData->m_nDataLength == 0;
+
+  return wcslen(ptr) == static_cast<size_t>(m_pData->m_nDataLength) &&
+         wmemcmp(ptr, m_pData->m_String, m_pData->m_nDataLength) == 0;
+}
+
+bool CFX_WideString::operator==(const CFX_WideStringC& str) const {
+  if (!m_pData)
+    return str.IsEmpty();
+
+  return m_pData->m_nDataLength == str.GetLength() &&
+         wmemcmp(m_pData->m_String, str.c_str(), str.GetLength()) == 0;
+}
+
+bool CFX_WideString::operator==(const CFX_WideString& other) const {
+  if (m_pData == other.m_pData)
+    return true;
+
+  if (IsEmpty())
+    return other.IsEmpty();
+
+  if (other.IsEmpty())
+    return false;
+
+  return other.m_pData->m_nDataLength == m_pData->m_nDataLength &&
+         wmemcmp(other.m_pData->m_String, m_pData->m_String,
+                 m_pData->m_nDataLength) == 0;
+}
+
+bool CFX_WideString::operator<(const CFX_WideString& str) const {
+  if (m_pData == str.m_pData)
+    return false;
+
+  int result =
+      wmemcmp(c_str(), str.c_str(), std::min(GetLength(), str.GetLength()));
+  return result < 0 || (result == 0 && GetLength() < str.GetLength());
+}
+
+void CFX_WideString::AssignCopy(const wchar_t* pSrcData, FX_STRSIZE nSrcLen) {
+  AllocBeforeWrite(nSrcLen);
+  m_pData->CopyContents(pSrcData, nSrcLen);
+  m_pData->m_nDataLength = nSrcLen;
+}
+
+void CFX_WideString::ReallocBeforeWrite(FX_STRSIZE nNewLength) {
+  if (m_pData && m_pData->CanOperateInPlace(nNewLength))
+    return;
+
+  if (nNewLength <= 0) {
+    clear();
+    return;
+  }
+
+  CFX_RetainPtr<StringData> pNewData(StringData::Create(nNewLength));
+  if (m_pData) {
+    FX_STRSIZE nCopyLength = std::min(m_pData->m_nDataLength, nNewLength);
+    pNewData->CopyContents(m_pData->m_String, nCopyLength);
+    pNewData->m_nDataLength = nCopyLength;
+  } else {
+    pNewData->m_nDataLength = 0;
+  }
+  pNewData->m_String[pNewData->m_nDataLength] = 0;
+  m_pData.Swap(pNewData);
+}
+
+void CFX_WideString::AllocBeforeWrite(FX_STRSIZE nNewLength) {
+  if (m_pData && m_pData->CanOperateInPlace(nNewLength))
+    return;
+
+  if (nNewLength <= 0) {
+    clear();
+    return;
+  }
+
+  m_pData.Reset(StringData::Create(nNewLength));
+}
+
+void CFX_WideString::ReleaseBuffer(FX_STRSIZE nNewLength) {
+  if (!m_pData)
+    return;
+
+  if (nNewLength == -1)
+    nNewLength = FXSYS_wcslen(m_pData->m_String);
+
+  nNewLength = std::min(nNewLength, m_pData->m_nAllocLength);
+  if (nNewLength == 0) {
+    clear();
+    return;
+  }
+
+  ASSERT(m_pData->m_nRefs == 1);
+  m_pData->m_nDataLength = nNewLength;
+  m_pData->m_String[nNewLength] = 0;
+  if (m_pData->m_nAllocLength - nNewLength >= 32) {
+    // Over arbitrary threshold, so pay the price to relocate.  Force copy to
+    // always occur by holding a second reference to the string.
+    CFX_WideString preserve(*this);
+    ReallocBeforeWrite(nNewLength);
+  }
+}
+
+void CFX_WideString::Reserve(FX_STRSIZE len) {
+  GetBuffer(len);
+}
+
+wchar_t* CFX_WideString::GetBuffer(FX_STRSIZE nMinBufLength) {
+  if (!m_pData) {
+    if (nMinBufLength == 0)
+      return nullptr;
+
+    m_pData.Reset(StringData::Create(nMinBufLength));
+    m_pData->m_nDataLength = 0;
+    m_pData->m_String[0] = 0;
+    return m_pData->m_String;
+  }
+
+  if (m_pData->CanOperateInPlace(nMinBufLength))
+    return m_pData->m_String;
+
+  nMinBufLength = std::max(nMinBufLength, m_pData->m_nDataLength);
+  if (nMinBufLength == 0)
+    return nullptr;
+
+  CFX_RetainPtr<StringData> pNewData(StringData::Create(nMinBufLength));
+  pNewData->CopyContents(*m_pData);
+  pNewData->m_nDataLength = m_pData->m_nDataLength;
+  m_pData.Swap(pNewData);
+  return m_pData->m_String;
+}
+
+FX_STRSIZE CFX_WideString::Delete(FX_STRSIZE nIndex, FX_STRSIZE nCount) {
+  if (!m_pData)
+    return 0;
+
+  if (nIndex < 0)
+    nIndex = 0;
+
+  FX_STRSIZE nOldLength = m_pData->m_nDataLength;
+  if (nCount > 0 && nIndex < nOldLength) {
+    FX_STRSIZE mLength = nIndex + nCount;
+    if (mLength >= nOldLength) {
+      m_pData->m_nDataLength = nIndex;
+      return m_pData->m_nDataLength;
+    }
+    ReallocBeforeWrite(nOldLength);
+    int nCharsToCopy = nOldLength - mLength + 1;
+    wmemmove(m_pData->m_String + nIndex, m_pData->m_String + mLength,
+             nCharsToCopy);
+    m_pData->m_nDataLength = nOldLength - nCount;
+  }
+  return m_pData->m_nDataLength;
+}
+
+void CFX_WideString::Concat(const wchar_t* pSrcData, FX_STRSIZE nSrcLen) {
+  if (!pSrcData || nSrcLen <= 0)
+    return;
+
+  if (!m_pData) {
+    m_pData.Reset(StringData::Create(pSrcData, nSrcLen));
+    return;
+  }
+
+  if (m_pData->CanOperateInPlace(m_pData->m_nDataLength + nSrcLen)) {
+    m_pData->CopyContentsAt(m_pData->m_nDataLength, pSrcData, nSrcLen);
+    m_pData->m_nDataLength += nSrcLen;
+    return;
+  }
+
+  CFX_RetainPtr<StringData> pNewData(
+      StringData::Create(m_pData->m_nDataLength + nSrcLen));
+  pNewData->CopyContents(*m_pData);
+  pNewData->CopyContentsAt(m_pData->m_nDataLength, pSrcData, nSrcLen);
+  m_pData.Swap(pNewData);
+}
+
+CFX_ByteString CFX_WideString::UTF8Encode() const {
+  return FX_UTF8Encode(AsStringC());
+}
+
+CFX_ByteString CFX_WideString::UTF16LE_Encode() const {
+  if (!m_pData) {
+    return CFX_ByteString("\0\0", 2);
+  }
+  int len = m_pData->m_nDataLength;
+  CFX_ByteString result;
+  char* 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;
+  }
+  buffer[len * 2] = 0;
+  buffer[len * 2 + 1] = 0;
+  result.ReleaseBuffer(len * 2 + 2);
+  return result;
+}
+
+CFX_WideString CFX_WideString::Mid(FX_STRSIZE nFirst) const {
+  if (!m_pData)
+    return CFX_WideString();
+
+  return Mid(nFirst, m_pData->m_nDataLength - nFirst);
+}
+
+CFX_WideString CFX_WideString::Mid(FX_STRSIZE nFirst, FX_STRSIZE nCount) const {
+  if (!m_pData)
+    return CFX_WideString();
+
+  nFirst = pdfium::clamp(nFirst, 0, m_pData->m_nDataLength);
+  nCount = pdfium::clamp(nCount, 0, m_pData->m_nDataLength - nFirst);
+  if (nCount == 0)
+    return CFX_WideString();
+
+  if (nFirst == 0 && nCount == m_pData->m_nDataLength)
+    return *this;
+
+  CFX_WideString dest;
+  AllocCopy(dest, nCount, nFirst);
+  return dest;
+}
+
+void CFX_WideString::AllocCopy(CFX_WideString& dest,
+                               FX_STRSIZE nCopyLen,
+                               FX_STRSIZE nCopyIndex) const {
+  if (nCopyLen <= 0)
+    return;
+
+  CFX_RetainPtr<StringData> pNewData(
+      StringData::Create(m_pData->m_String + nCopyIndex, nCopyLen));
+  dest.m_pData.Swap(pNewData);
+}
+
+bool CFX_WideString::TryVSWPrintf(FX_STRSIZE size,
+                                  const wchar_t* pFormat,
+                                  va_list argList) {
+  GetBuffer(size);
+  if (!m_pData)
+    return true;
+
+  // In the following two calls, there's always space in the buffer for
+  // a terminating NUL that's not included in nMaxLen.
+  // For vswprintf(), MSAN won't untaint the buffer on a truncated write's
+  // -1 return code even though the buffer is written. Probably just as well
+  // not to trust the vendor's implementation to write anything anyways.
+  // See https://crbug.com/705912.
+  memset(m_pData->m_String, 0, (size + 1) * sizeof(wchar_t));
+  int ret = vswprintf(m_pData->m_String, size + 1, pFormat, argList);
+  ReleaseBuffer();
+  return ret >= 0 || m_pData->m_String[size - 1] == 0;
+}
+
+void CFX_WideString::FormatV(const wchar_t* pFormat, va_list argList) {
+  va_list argListCopy;
+  FX_VA_COPY(argListCopy, argList);
+  FX_STRSIZE nMaxLen = vswprintf(nullptr, 0, pFormat, argListCopy);
+  va_end(argListCopy);
+  if (nMaxLen <= 0) {
+    nMaxLen = GuessSizeForVSWPrintf(pFormat, argListCopy);
+    if (nMaxLen <= 0)
+      return;
+  }
+  while (nMaxLen < 32 * 1024) {
+    FX_VA_COPY(argListCopy, argList);
+    bool bRetryPointless = TryVSWPrintf(nMaxLen, pFormat, argListCopy);
+    va_end(argListCopy);
+    if (bRetryPointless)
+      break;
+    nMaxLen *= 2;
+  }
+}
+
+void CFX_WideString::Format(const wchar_t* pFormat, ...) {
+  va_list argList;
+  va_start(argList, pFormat);
+  FormatV(pFormat, argList);
+  va_end(argList);
+}
+
+FX_STRSIZE CFX_WideString::Insert(FX_STRSIZE nIndex, wchar_t ch) {
+  FX_STRSIZE nNewLength = m_pData ? m_pData->m_nDataLength : 0;
+  nIndex = std::max(nIndex, 0);
+  nIndex = std::min(nIndex, nNewLength);
+  nNewLength++;
+
+  ReallocBeforeWrite(nNewLength);
+  wmemmove(m_pData->m_String + nIndex + 1, m_pData->m_String + nIndex,
+           nNewLength - nIndex);
+  m_pData->m_String[nIndex] = ch;
+  m_pData->m_nDataLength = nNewLength;
+  return nNewLength;
+}
+
+CFX_WideString CFX_WideString::Right(FX_STRSIZE nCount) const {
+  if (!m_pData)
+    return CFX_WideString();
+
+  nCount = std::max(nCount, 0);
+  if (nCount >= m_pData->m_nDataLength)
+    return *this;
+
+  CFX_WideString dest;
+  AllocCopy(dest, nCount, m_pData->m_nDataLength - nCount);
+  return dest;
+}
+
+CFX_WideString CFX_WideString::Left(FX_STRSIZE nCount) const {
+  if (!m_pData)
+    return CFX_WideString();
+
+  nCount = std::max(nCount, 0);
+  if (nCount >= m_pData->m_nDataLength)
+    return *this;
+
+  CFX_WideString dest;
+  AllocCopy(dest, nCount, 0);
+  return dest;
+}
+
+FX_STRSIZE CFX_WideString::Find(wchar_t ch, FX_STRSIZE nStart) const {
+  if (!m_pData)
+    return -1;
+
+  if (nStart < 0 || nStart >= m_pData->m_nDataLength)
+    return -1;
+
+  const wchar_t* pStr =
+      wmemchr(m_pData->m_String + nStart, ch, m_pData->m_nDataLength - nStart);
+  return pStr ? pStr - m_pData->m_String : -1;
+}
+
+FX_STRSIZE CFX_WideString::Find(const CFX_WideStringC& pSub,
+                                FX_STRSIZE nStart) const {
+  if (!m_pData)
+    return -1;
+
+  FX_STRSIZE nLength = m_pData->m_nDataLength;
+  if (nStart > nLength)
+    return -1;
+
+  const wchar_t* pStr =
+      FX_wcsstr(m_pData->m_String + nStart, m_pData->m_nDataLength - nStart,
+                pSub.c_str(), pSub.GetLength());
+  return pStr ? (int)(pStr - m_pData->m_String) : -1;
+}
+
+void CFX_WideString::MakeLower() {
+  if (!m_pData)
+    return;
+
+  ReallocBeforeWrite(m_pData->m_nDataLength);
+  FXSYS_wcslwr(m_pData->m_String);
+}
+
+void CFX_WideString::MakeUpper() {
+  if (!m_pData)
+    return;
+
+  ReallocBeforeWrite(m_pData->m_nDataLength);
+  FXSYS_wcsupr(m_pData->m_String);
+}
+
+FX_STRSIZE CFX_WideString::Remove(wchar_t chRemove) {
+  if (!m_pData || m_pData->m_nDataLength < 1)
+    return 0;
+
+  wchar_t* pstrSource = m_pData->m_String;
+  wchar_t* pstrEnd = m_pData->m_String + m_pData->m_nDataLength;
+  while (pstrSource < pstrEnd) {
+    if (*pstrSource == chRemove)
+      break;
+    pstrSource++;
+  }
+  if (pstrSource == pstrEnd)
+    return 0;
+
+  ptrdiff_t copied = pstrSource - m_pData->m_String;
+  ReallocBeforeWrite(m_pData->m_nDataLength);
+  pstrSource = m_pData->m_String + copied;
+  pstrEnd = m_pData->m_String + m_pData->m_nDataLength;
+
+  wchar_t* pstrDest = pstrSource;
+  while (pstrSource < pstrEnd) {
+    if (*pstrSource != chRemove) {
+      *pstrDest = *pstrSource;
+      pstrDest++;
+    }
+    pstrSource++;
+  }
+
+  *pstrDest = 0;
+  FX_STRSIZE nCount = (FX_STRSIZE)(pstrSource - pstrDest);
+  m_pData->m_nDataLength -= nCount;
+  return nCount;
+}
+
+FX_STRSIZE CFX_WideString::Replace(const CFX_WideStringC& pOld,
+                                   const CFX_WideStringC& pNew) {
+  if (!m_pData || pOld.IsEmpty())
+    return 0;
+
+  FX_STRSIZE nSourceLen = pOld.GetLength();
+  FX_STRSIZE nReplacementLen = pNew.GetLength();
+  FX_STRSIZE nCount = 0;
+  const wchar_t* pStart = m_pData->m_String;
+  wchar_t* pEnd = m_pData->m_String + m_pData->m_nDataLength;
+  while (1) {
+    const wchar_t* pTarget = FX_wcsstr(pStart, (FX_STRSIZE)(pEnd - pStart),
+                                       pOld.c_str(), nSourceLen);
+    if (!pTarget)
+      break;
+
+    nCount++;
+    pStart = pTarget + nSourceLen;
+  }
+  if (nCount == 0)
+    return 0;
+
+  FX_STRSIZE nNewLength =
+      m_pData->m_nDataLength + (nReplacementLen - nSourceLen) * nCount;
+
+  if (nNewLength == 0) {
+    clear();
+    return nCount;
+  }
+
+  CFX_RetainPtr<StringData> pNewData(StringData::Create(nNewLength));
+  pStart = m_pData->m_String;
+  wchar_t* pDest = pNewData->m_String;
+  for (FX_STRSIZE i = 0; i < nCount; i++) {
+    const wchar_t* pTarget = FX_wcsstr(pStart, (FX_STRSIZE)(pEnd - pStart),
+                                       pOld.c_str(), nSourceLen);
+    wmemcpy(pDest, pStart, pTarget - pStart);
+    pDest += pTarget - pStart;
+    wmemcpy(pDest, pNew.c_str(), pNew.GetLength());
+    pDest += pNew.GetLength();
+    pStart = pTarget + nSourceLen;
+  }
+  wmemcpy(pDest, pStart, pEnd - pStart);
+  m_pData.Swap(pNewData);
+  return nCount;
+}
+
+void CFX_WideString::SetAt(FX_STRSIZE nIndex, wchar_t ch) {
+  if (!m_pData) {
+    return;
+  }
+  ASSERT(nIndex >= 0);
+  ASSERT(nIndex < m_pData->m_nDataLength);
+  ReallocBeforeWrite(m_pData->m_nDataLength);
+  m_pData->m_String[nIndex] = ch;
+}
+
+// static
+CFX_WideString CFX_WideString::FromLocal(const CFX_ByteStringC& str) {
+  return FromCodePage(str, 0);
+}
+
+// static
+CFX_WideString CFX_WideString::FromCodePage(const CFX_ByteStringC& str,
+                                            uint16_t codepage) {
+  return CFX_CharMap::GetWideString(codepage, str);
+}
+
+// static
+CFX_WideString CFX_WideString::FromUTF8(const CFX_ByteStringC& str) {
+  if (str.IsEmpty())
+    return CFX_WideString();
+
+  CFX_UTF8Decoder decoder;
+  for (FX_STRSIZE i = 0; i < str.GetLength(); i++)
+    decoder.Input(str[i]);
+
+  return CFX_WideString(decoder.GetResult());
+}
+
+// static
+CFX_WideString CFX_WideString::FromUTF16LE(const unsigned short* wstr,
+                                           FX_STRSIZE wlen) {
+  if (!wstr || 0 == wlen) {
+    return CFX_WideString();
+  }
+
+  CFX_WideString result;
+  wchar_t* buf = result.GetBuffer(wlen);
+  for (int i = 0; i < wlen; i++) {
+    buf[i] = wstr[i];
+  }
+  result.ReleaseBuffer(wlen);
+  return result;
+}
+
+int CFX_WideString::Compare(const wchar_t* lpsz) const {
+  if (m_pData)
+    return FXSYS_wcscmp(m_pData->m_String, lpsz);
+  return (!lpsz || lpsz[0] == 0) ? 0 : -1;
+}
+
+int CFX_WideString::Compare(const CFX_WideString& str) const {
+  if (!m_pData) {
+    if (!str.m_pData) {
+      return 0;
+    }
+    return -1;
+  }
+  if (!str.m_pData) {
+    return 1;
+  }
+  int this_len = m_pData->m_nDataLength;
+  int that_len = str.m_pData->m_nDataLength;
+  int min_len = this_len < that_len ? this_len : that_len;
+  for (int i = 0; i < min_len; i++) {
+    if (m_pData->m_String[i] < str.m_pData->m_String[i]) {
+      return -1;
+    }
+    if (m_pData->m_String[i] > str.m_pData->m_String[i]) {
+      return 1;
+    }
+  }
+  if (this_len < that_len) {
+    return -1;
+  }
+  if (this_len > that_len) {
+    return 1;
+  }
+  return 0;
+}
+
+int CFX_WideString::CompareNoCase(const wchar_t* lpsz) const {
+  if (!m_pData) {
+    return (!lpsz || lpsz[0] == 0) ? 0 : -1;
+  }
+  return FXSYS_wcsicmp(m_pData->m_String, lpsz);
+}
+
+FX_STRSIZE CFX_WideString::WStringLength(const unsigned short* str) {
+  FX_STRSIZE len = 0;
+  if (str)
+    while (str[len])
+      len++;
+  return len;
+}
+
+void CFX_WideString::TrimRight(const CFX_WideStringC& pTargets) {
+  if (IsEmpty() || pTargets.IsEmpty())
+    return;
+
+  FX_STRSIZE pos = GetLength();
+  while (pos && pTargets.Find(m_pData->m_String[pos - 1]) != -1)
+    pos--;
+
+  if (pos < m_pData->m_nDataLength) {
+    ReallocBeforeWrite(m_pData->m_nDataLength);
+    m_pData->m_String[pos] = 0;
+    m_pData->m_nDataLength = pos;
+  }
+}
+
+void CFX_WideString::TrimRight(wchar_t chTarget) {
+  wchar_t str[2] = {chTarget, 0};
+  TrimRight(str);
+}
+
+void CFX_WideString::TrimRight() {
+  TrimRight(L"\x09\x0a\x0b\x0c\x0d\x20");
+}
+
+void CFX_WideString::TrimLeft(const CFX_WideStringC& pTargets) {
+  if (!m_pData || pTargets.IsEmpty())
+    return;
+
+  FX_STRSIZE len = GetLength();
+  if (len < 1)
+    return;
+
+  FX_STRSIZE pos = 0;
+  while (pos < len) {
+    FX_STRSIZE i = 0;
+    while (i < pTargets.GetLength() &&
+           pTargets.CharAt(i) != m_pData->m_String[pos]) {
+      i++;
+    }
+    if (i == pTargets.GetLength()) {
+      break;
+    }
+    pos++;
+  }
+  if (pos) {
+    ReallocBeforeWrite(len);
+    FX_STRSIZE nDataLength = len - pos;
+    FXSYS_memmove(m_pData->m_String, m_pData->m_String + pos,
+                  (nDataLength + 1) * sizeof(wchar_t));
+    m_pData->m_nDataLength = nDataLength;
+  }
+}
+
+void CFX_WideString::TrimLeft(wchar_t chTarget) {
+  wchar_t str[2] = {chTarget, 0};
+  TrimLeft(str);
+}
+
+void CFX_WideString::TrimLeft() {
+  TrimLeft(L"\x09\x0a\x0b\x0c\x0d\x20");
+}
+float FX_wtof(const wchar_t* str, int len) {
+  if (len == 0) {
+    return 0.0;
+  }
+  int cc = 0;
+  bool bNegative = false;
+  if (str[0] == '+') {
+    cc++;
+  } else if (str[0] == '-') {
+    bNegative = true;
+    cc++;
+  }
+  int integer = 0;
+  while (cc < len) {
+    if (str[cc] == '.') {
+      break;
+    }
+    integer = integer * 10 + FXSYS_toDecimalDigit(str[cc]);
+    cc++;
+  }
+  float fraction = 0;
+  if (str[cc] == '.') {
+    cc++;
+    float scale = 0.1f;
+    while (cc < len) {
+      fraction += scale * FXSYS_toDecimalDigit(str[cc]);
+      scale *= 0.1f;
+      cc++;
+    }
+  }
+  fraction += (float)integer;
+  return bNegative ? -fraction : fraction;
+}
+
+int CFX_WideString::GetInteger() const {
+  return m_pData ? FXSYS_wtoi(m_pData->m_String) : 0;
+}
+
+float CFX_WideString::GetFloat() const {
+  return m_pData ? FX_wtof(m_pData->m_String, m_pData->m_nDataLength) : 0.0f;
+}
+
+// static
+CFX_ByteString CFX_CharMap::GetByteString(uint16_t codepage,
+                                          const CFX_WideStringC& wstr) {
+  ASSERT(IsValidCodePage(codepage));
+  int src_len = wstr.GetLength();
+  int dest_len = FXSYS_WideCharToMultiByte(codepage, 0, wstr.c_str(), src_len,
+                                           nullptr, 0, nullptr, nullptr);
+  CFX_ByteString bstr;
+  if (dest_len) {
+    char* dest_buf = bstr.GetBuffer(dest_len);
+    FXSYS_WideCharToMultiByte(codepage, 0, wstr.c_str(), src_len, dest_buf,
+                              dest_len, nullptr, nullptr);
+    bstr.ReleaseBuffer(dest_len);
+  }
+  return bstr;
+}
+
+// static
+CFX_WideString CFX_CharMap::GetWideString(uint16_t codepage,
+                                          const CFX_ByteStringC& bstr) {
+  ASSERT(IsValidCodePage(codepage));
+  int src_len = bstr.GetLength();
+  int dest_len =
+      FXSYS_MultiByteToWideChar(codepage, 0, bstr.c_str(), src_len, nullptr, 0);
+  CFX_WideString wstr;
+  if (dest_len) {
+    wchar_t* dest_buf = wstr.GetBuffer(dest_len);
+    FXSYS_MultiByteToWideChar(codepage, 0, bstr.c_str(), src_len, dest_buf,
+                              dest_len);
+    wstr.ReleaseBuffer(dest_len);
+  }
+  return wstr;
+}