text: // 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
  
  #ifndef CORE_FXCRT_FX_EXTENSION_H_
  #define CORE_FXCRT_FX_EXTENSION_H_
  
  #include <cctype>
  #include <cmath>
  #include <cwctype>
  #include <memory>
  
  #include "core/fxcrt/fx_string.h"
  #include "third_party/base/span.h"
  
  #if defined(USE_SYSTEM_ICUUC)
  #include <unicode/uchar.h>
  #else
  #include "third_party/icu/source/common/unicode/uchar.h"
  #endif
  
  #define FX_INVALID_OFFSET static_cast<uint32_t>(-1)
  
  #ifdef PDF_ENABLE_XFA
  #define FX_IsOdd(a) ((a)&1)
  #endif  // PDF_ENABLE_XFA
  
  float FXSYS_wcstof(const wchar_t* pwsStr, int32_t iLength, int32_t* pUsedLen);
  wchar_t* FXSYS_wcsncpy(wchar_t* dstStr, const wchar_t* srcStr, size_t count);
  int32_t FXSYS_wcsnicmp(const wchar_t* s1, const wchar_t* s2, size_t count);
  
  inline bool FXSYS_iswlower(int32_t c) {
    return u_islower(c);
  }
  
  inline bool FXSYS_iswupper(int32_t c) {
    return u_isupper(c);
  }
  
  inline int32_t FXSYS_towlower(wchar_t c) {
    return u_tolower(c);
  }
  
  inline int32_t FXSYS_towupper(wchar_t c) {
    return u_toupper(c);
  }
  
  inline bool FXSYS_iswalpha(wchar_t c) {
    return u_isalpha(c);
  }
  
  inline bool FXSYS_iswalnum(wchar_t c) {
    return u_isalnum(c);
  }
  
  inline bool FXSYS_iswspace(wchar_t c) {
    return u_isspace(c);
  }
  
  inline bool FXSYS_isHexDigit(const char c) {
    return !((c & 0x80) || !std::isxdigit(c));
  }
  
  inline int FXSYS_HexCharToInt(const char c) {
    if (!FXSYS_isHexDigit(c))
      return 0;
    char upchar = std::toupper(c);
    return upchar > '9' ? upchar - 'A' + 10 : upchar - '0';
  }
  
  inline bool FXSYS_isDecimalDigit(const char c) {
    return !((c & 0x80) || !std::isdigit(c));
  }
  
  inline bool FXSYS_isDecimalDigit(const wchar_t c) {
    return !!std::iswdigit(c);
  }
  
  inline int FXSYS_DecimalCharToInt(const char c) {
    return FXSYS_isDecimalDigit(c) ? c - '0' : 0;
  }
  
  inline int FXSYS_DecimalCharToInt(const wchar_t c) {
    return std::iswdigit(c) ? c - L'0' : 0;
  }
  
  void FXSYS_IntToTwoHexChars(uint8_t c, char* buf);
  void FXSYS_IntToFourHexChars(uint16_t c, char* buf);
  
  size_t FXSYS_ToUTF16BE(uint32_t unicode, char* buf);
  
  // Strict order over floating types where NaNs may be present.
  template <typename T>
  bool FXSYS_SafeEQ(const T& lhs, const T& rhs) {
    return (std::isnan(lhs) && std::isnan(rhs)) ||
           (!std::isnan(lhs) && !std::isnan(rhs) && lhs == rhs);
  }
  
  template <typename T>
  bool FXSYS_SafeLT(const T& lhs, const T& rhs) {
    if (std::isnan(lhs) && std::isnan(rhs))
      return false;
    if (std::isnan(lhs) || std::isnan(rhs))
      return std::isnan(lhs) < std::isnan(rhs);
    return lhs < rhs;
  }
  
  void FXSYS_SetTimeFunction(time_t (*func)());
  time_t FXSYS_time(time_t* tloc);
  
  #endif  // CORE_FXCRT_FX_EXTENSION_H_
  