unistr.h

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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
**********************************************************************
*   Copyright (C) 1998-2016, International Business Machines
*   Corporation and others.  All Rights Reserved.
**********************************************************************
*
* File unistr.h
*
* Modification History:
*
*   Date        Name        Description
*   09/25/98    stephen     Creation.
*   11/11/98    stephen     Changed per 11/9 code review.
*   04/20/99    stephen     Overhauled per 4/16 code review.
*   11/18/99    aliu        Made to inherit from Replaceable.  Added method
*                           handleReplaceBetween(); other methods unchanged.
*   06/25/01    grhoten     Remove dependency on iostream.
******************************************************************************
*/

#ifndef UNISTR_H
#define UNISTR_H

#include "unicode/utypes.h"

#if U_SHOW_CPLUSPLUS_API

#include <cstddef>
#include "unicode/char16ptr.h"
#include "unicode/rep.h"
#include "unicode/std_string.h"
#include "unicode/stringpiece.h"
#include "unicode/bytestream.h"

struct UConverter;          // unicode/ucnv.h

#ifndef USTRING_H

U_CAPI int32_t U_EXPORT2 u_strlen(const UChar *s);
#endif

U_NAMESPACE_BEGIN

#if !UCONFIG_NO_BREAK_ITERATION
class BreakIterator;        // unicode/brkiter.h
#endif
class Edits;

U_NAMESPACE_END

// Not #ifndef U_HIDE_INTERNAL_API because UnicodeString needs the UStringCaseMapper.
typedef int32_t U_CALLCONV
UStringCaseMapper(int32_t caseLocale, uint32_t options,
#if !UCONFIG_NO_BREAK_ITERATION
                  icu::BreakIterator *iter,
#endif
                  char16_t *dest, int32_t destCapacity,
                  const char16_t *src, int32_t srcLength,
                  icu::Edits *edits,
                  UErrorCode &errorCode);

U_NAMESPACE_BEGIN

class Locale;               // unicode/locid.h
class StringCharacterIterator;
class UnicodeStringAppendable;  // unicode/appendable.h

/* The <iostream> include has been moved to unicode/ustream.h */

#define US_INV icu::UnicodeString::kInvariant

#if !U_CHAR16_IS_TYPEDEF
# define UNICODE_STRING(cs, _length) icu::UnicodeString(true, u ## cs, _length)
#else
# define UNICODE_STRING(cs, _length) icu::UnicodeString(true, (const char16_t*)u ## cs, _length)
#endif

#define UNICODE_STRING_SIMPLE(cs) UNICODE_STRING(cs, -1)

#ifndef UNISTR_FROM_CHAR_EXPLICIT
# if defined(U_COMBINED_IMPLEMENTATION) || defined(U_COMMON_IMPLEMENTATION) || defined(U_I18N_IMPLEMENTATION) || defined(U_IO_IMPLEMENTATION)
    // Auto-"explicit" in ICU library code.
#   define UNISTR_FROM_CHAR_EXPLICIT explicit
# else
    // Empty by default for source code compatibility.
#   define UNISTR_FROM_CHAR_EXPLICIT
# endif
#endif

#ifndef UNISTR_FROM_STRING_EXPLICIT
# if defined(U_COMBINED_IMPLEMENTATION) || defined(U_COMMON_IMPLEMENTATION) || defined(U_I18N_IMPLEMENTATION) || defined(U_IO_IMPLEMENTATION)
    // Auto-"explicit" in ICU library code.
#   define UNISTR_FROM_STRING_EXPLICIT explicit
# else
    // Empty by default for source code compatibility.
#   define UNISTR_FROM_STRING_EXPLICIT
# endif
#endif

#ifndef UNISTR_OBJECT_SIZE
# define UNISTR_OBJECT_SIZE 64
#endif

class U_COMMON_API UnicodeString : public Replaceable
{
public:

  enum EInvariant {
    kInvariant
  };

  //========================================
  // Read-only operations
  //========================================

  /* Comparison - bitwise only - for international comparison use collation */

  inline bool operator== (const UnicodeString& text) const;

  inline bool operator!= (const UnicodeString& text) const;

  inline UBool operator> (const UnicodeString& text) const;

  inline UBool operator< (const UnicodeString& text) const;

  inline UBool operator>= (const UnicodeString& text) const;

  inline UBool operator<= (const UnicodeString& text) const;

  inline int8_t compare(const UnicodeString& text) const;

  inline int8_t compare(int32_t start,
         int32_t length,
         const UnicodeString& text) const;

   inline int8_t compare(int32_t start,
         int32_t length,
         const UnicodeString& srcText,
         int32_t srcStart,
         int32_t srcLength) const;

  inline int8_t compare(ConstChar16Ptr srcChars,
         int32_t srcLength) const;

  inline int8_t compare(int32_t start,
         int32_t length,
         const char16_t *srcChars) const;

  inline int8_t compare(int32_t start,
         int32_t length,
         const char16_t *srcChars,
         int32_t srcStart,
         int32_t srcLength) const;

  inline int8_t compareBetween(int32_t start,
            int32_t limit,
            const UnicodeString& srcText,
            int32_t srcStart,
            int32_t srcLimit) const;

  inline int8_t compareCodePointOrder(const UnicodeString& text) const;

  inline int8_t compareCodePointOrder(int32_t start,
                                      int32_t length,
                                      const UnicodeString& srcText) const;

   inline int8_t compareCodePointOrder(int32_t start,
                                       int32_t length,
                                       const UnicodeString& srcText,
                                       int32_t srcStart,
                                       int32_t srcLength) const;

  inline int8_t compareCodePointOrder(ConstChar16Ptr srcChars,
                                      int32_t srcLength) const;

  inline int8_t compareCodePointOrder(int32_t start,
                                      int32_t length,
                                      const char16_t *srcChars) const;

  inline int8_t compareCodePointOrder(int32_t start,
                                      int32_t length,
                                      const char16_t *srcChars,
                                      int32_t srcStart,
                                      int32_t srcLength) const;

  inline int8_t compareCodePointOrderBetween(int32_t start,
                                             int32_t limit,
                                             const UnicodeString& srcText,
                                             int32_t srcStart,
                                             int32_t srcLimit) const;

  inline int8_t caseCompare(const UnicodeString& text, uint32_t options) const;

  inline int8_t caseCompare(int32_t start,
         int32_t length,
         const UnicodeString& srcText,
         uint32_t options) const;

  inline int8_t caseCompare(int32_t start,
         int32_t length,
         const UnicodeString& srcText,
         int32_t srcStart,
         int32_t srcLength,
         uint32_t options) const;

  inline int8_t caseCompare(ConstChar16Ptr srcChars,
         int32_t srcLength,
         uint32_t options) const;

  inline int8_t caseCompare(int32_t start,
         int32_t length,
         const char16_t *srcChars,
         uint32_t options) const;

  inline int8_t caseCompare(int32_t start,
         int32_t length,
         const char16_t *srcChars,
         int32_t srcStart,
         int32_t srcLength,
         uint32_t options) const;

  inline int8_t caseCompareBetween(int32_t start,
            int32_t limit,
            const UnicodeString& srcText,
            int32_t srcStart,
            int32_t srcLimit,
            uint32_t options) const;

  inline UBool startsWith(const UnicodeString& text) const;

  inline UBool startsWith(const UnicodeString& srcText,
            int32_t srcStart,
            int32_t srcLength) const;

  inline UBool startsWith(ConstChar16Ptr srcChars,
            int32_t srcLength) const;

  inline UBool startsWith(const char16_t *srcChars,
            int32_t srcStart,
            int32_t srcLength) const;

  inline UBool endsWith(const UnicodeString& text) const;

  inline UBool endsWith(const UnicodeString& srcText,
          int32_t srcStart,
          int32_t srcLength) const;

  inline UBool endsWith(ConstChar16Ptr srcChars,
          int32_t srcLength) const;

  inline UBool endsWith(const char16_t *srcChars,
          int32_t srcStart,
          int32_t srcLength) const;


  /* Searching - bitwise only */

  inline int32_t indexOf(const UnicodeString& text) const;

  inline int32_t indexOf(const UnicodeString& text,
              int32_t start) const;

  inline int32_t indexOf(const UnicodeString& text,
              int32_t start,
              int32_t length) const;

  inline int32_t indexOf(const UnicodeString& srcText,
              int32_t srcStart,
              int32_t srcLength,
              int32_t start,
              int32_t length) const;

  inline int32_t indexOf(const char16_t *srcChars,
              int32_t srcLength,
              int32_t start) const;

  inline int32_t indexOf(ConstChar16Ptr srcChars,
              int32_t srcLength,
              int32_t start,
              int32_t length) const;

  int32_t indexOf(const char16_t *srcChars,
              int32_t srcStart,
              int32_t srcLength,
              int32_t start,
              int32_t length) const;

  inline int32_t indexOf(char16_t c) const;

  inline int32_t indexOf(UChar32 c) const;

  inline int32_t indexOf(char16_t c,
              int32_t start) const;

  inline int32_t indexOf(UChar32 c,
              int32_t start) const;

  inline int32_t indexOf(char16_t c,
              int32_t start,
              int32_t length) const;

  inline int32_t indexOf(UChar32 c,
              int32_t start,
              int32_t length) const;

  inline int32_t lastIndexOf(const UnicodeString& text) const;

  inline int32_t lastIndexOf(const UnicodeString& text,
              int32_t start) const;

  inline int32_t lastIndexOf(const UnicodeString& text,
              int32_t start,
              int32_t length) const;

  inline int32_t lastIndexOf(const UnicodeString& srcText,
              int32_t srcStart,
              int32_t srcLength,
              int32_t start,
              int32_t length) const;

  inline int32_t lastIndexOf(const char16_t *srcChars,
              int32_t srcLength,
              int32_t start) const;

  inline int32_t lastIndexOf(ConstChar16Ptr srcChars,
              int32_t srcLength,
              int32_t start,
              int32_t length) const;

  int32_t lastIndexOf(const char16_t *srcChars,
              int32_t srcStart,
              int32_t srcLength,
              int32_t start,
              int32_t length) const;

  inline int32_t lastIndexOf(char16_t c) const;

  inline int32_t lastIndexOf(UChar32 c) const;

  inline int32_t lastIndexOf(char16_t c,
              int32_t start) const;

  inline int32_t lastIndexOf(UChar32 c,
              int32_t start) const;

  inline int32_t lastIndexOf(char16_t c,
              int32_t start,
              int32_t length) const;

  inline int32_t lastIndexOf(UChar32 c,
              int32_t start,
              int32_t length) const;


  /* Character access */

  inline char16_t charAt(int32_t offset) const;

  inline char16_t operator[] (int32_t offset) const;

  UChar32 char32At(int32_t offset) const;

  int32_t getChar32Start(int32_t offset) const;

  int32_t getChar32Limit(int32_t offset) const;

  int32_t moveIndex32(int32_t index, int32_t delta) const;

  /* Substring extraction */

  inline void extract(int32_t start,
           int32_t length,
           Char16Ptr dst,
           int32_t dstStart = 0) const;

  int32_t
  extract(Char16Ptr dest, int32_t destCapacity,
          UErrorCode &errorCode) const;

  inline void extract(int32_t start,
           int32_t length,
           UnicodeString& target) const;

  inline void extractBetween(int32_t start,
              int32_t limit,
              char16_t *dst,
              int32_t dstStart = 0) const;

  virtual void extractBetween(int32_t start,
              int32_t limit,
              UnicodeString& target) const override;

  int32_t extract(int32_t start,
           int32_t startLength,
           char *target,
           int32_t targetCapacity,
           enum EInvariant inv) const;

#if U_CHARSET_IS_UTF8 || !UCONFIG_NO_CONVERSION

  int32_t extract(int32_t start,
           int32_t startLength,
           char *target,
           uint32_t targetLength) const;

#endif

#if !UCONFIG_NO_CONVERSION

  inline int32_t extract(int32_t start,
                 int32_t startLength,
                 char *target,
                 const char *codepage = 0) const;

  int32_t extract(int32_t start,
           int32_t startLength,
           char *target,
           uint32_t targetLength,
           const char *codepage) const;

  int32_t extract(char *dest, int32_t destCapacity,
                  UConverter *cnv,
                  UErrorCode &errorCode) const;

#endif

  UnicodeString tempSubString(int32_t start=0, int32_t length=INT32_MAX) const;

  inline UnicodeString tempSubStringBetween(int32_t start, int32_t limit=INT32_MAX) const;

  void toUTF8(ByteSink &sink) const;

  template<typename StringClass>
  StringClass &toUTF8String(StringClass &result) const {
    StringByteSink<StringClass> sbs(&result, length());
    toUTF8(sbs);
    return result;
  }

  int32_t toUTF32(UChar32 *utf32, int32_t capacity, UErrorCode &errorCode) const;

  /* Length operations */

  inline int32_t length(void) const;

  int32_t
  countChar32(int32_t start=0, int32_t length=INT32_MAX) const;

  UBool
  hasMoreChar32Than(int32_t start, int32_t length, int32_t number) const;

  inline UBool isEmpty(void) const;

  inline int32_t getCapacity(void) const;

  /* Other operations */

  inline int32_t hashCode(void) const;

  inline UBool isBogus(void) const;


  //========================================
  // Write operations
  //========================================

  /* Assignment operations */

  UnicodeString &operator=(const UnicodeString &srcText);

  UnicodeString &fastCopyFrom(const UnicodeString &src);

  UnicodeString &operator=(UnicodeString &&src) noexcept;

  void swap(UnicodeString &other) noexcept;

  friend inline void U_EXPORT2
  swap(UnicodeString &s1, UnicodeString &s2) noexcept {
    s1.swap(s2);
  }

  inline UnicodeString& operator= (char16_t ch);

  inline UnicodeString& operator= (UChar32 ch);

  inline UnicodeString& setTo(const UnicodeString& srcText,
               int32_t srcStart);

  inline UnicodeString& setTo(const UnicodeString& srcText,
               int32_t srcStart,
               int32_t srcLength);

  inline UnicodeString& setTo(const UnicodeString& srcText);

  inline UnicodeString& setTo(const char16_t *srcChars,
               int32_t srcLength);

  inline UnicodeString& setTo(char16_t srcChar);

  inline UnicodeString& setTo(UChar32 srcChar);

  UnicodeString &setTo(UBool isTerminated,
                       ConstChar16Ptr text,
                       int32_t textLength);

  UnicodeString &setTo(char16_t *buffer,
                       int32_t buffLength,
                       int32_t buffCapacity);

  void setToBogus();

  UnicodeString& setCharAt(int32_t offset,
               char16_t ch);


  /* Append operations */

 inline  UnicodeString& operator+= (char16_t ch);

 inline  UnicodeString& operator+= (UChar32 ch);

  inline UnicodeString& operator+= (const UnicodeString& srcText);

  inline UnicodeString& append(const UnicodeString& srcText,
            int32_t srcStart,
            int32_t srcLength);

  inline UnicodeString& append(const UnicodeString& srcText);

  inline UnicodeString& append(const char16_t *srcChars,
            int32_t srcStart,
            int32_t srcLength);

  inline UnicodeString& append(ConstChar16Ptr srcChars,
            int32_t srcLength);

  inline UnicodeString& append(char16_t srcChar);

  UnicodeString& append(UChar32 srcChar);


  /* Insert operations */

  inline UnicodeString& insert(int32_t start,
            const UnicodeString& srcText,
            int32_t srcStart,
            int32_t srcLength);

  inline UnicodeString& insert(int32_t start,
            const UnicodeString& srcText);

  inline UnicodeString& insert(int32_t start,
            const char16_t *srcChars,
            int32_t srcStart,
            int32_t srcLength);

  inline UnicodeString& insert(int32_t start,
            ConstChar16Ptr srcChars,
            int32_t srcLength);

  inline UnicodeString& insert(int32_t start,
            char16_t srcChar);

  inline UnicodeString& insert(int32_t start,
            UChar32 srcChar);


  /* Replace operations */

  inline UnicodeString& replace(int32_t start,
             int32_t length,
             const UnicodeString& srcText,
             int32_t srcStart,
             int32_t srcLength);

  inline UnicodeString& replace(int32_t start,
             int32_t length,
             const UnicodeString& srcText);

  inline UnicodeString& replace(int32_t start,
             int32_t length,
             const char16_t *srcChars,
             int32_t srcStart,
             int32_t srcLength);

  inline UnicodeString& replace(int32_t start,
             int32_t length,
             ConstChar16Ptr srcChars,
             int32_t srcLength);

  inline UnicodeString& replace(int32_t start,
             int32_t length,
             char16_t srcChar);

  UnicodeString& replace(int32_t start, int32_t length, UChar32 srcChar);

  inline UnicodeString& replaceBetween(int32_t start,
                int32_t limit,
                const UnicodeString& srcText);

  inline UnicodeString& replaceBetween(int32_t start,
                int32_t limit,
                const UnicodeString& srcText,
                int32_t srcStart,
                int32_t srcLimit);

  virtual void handleReplaceBetween(int32_t start,
                                    int32_t limit,
                                    const UnicodeString& text) override;

  virtual UBool hasMetaData() const override;

  virtual void copy(int32_t start, int32_t limit, int32_t dest) override;

  /* Search and replace operations */

  inline UnicodeString& findAndReplace(const UnicodeString& oldText,
                const UnicodeString& newText);

  inline UnicodeString& findAndReplace(int32_t start,
                int32_t length,
                const UnicodeString& oldText,
                const UnicodeString& newText);

  UnicodeString& findAndReplace(int32_t start,
                int32_t length,
                const UnicodeString& oldText,
                int32_t oldStart,
                int32_t oldLength,
                const UnicodeString& newText,
                int32_t newStart,
                int32_t newLength);


  /* Remove operations */

  inline UnicodeString& remove();

  inline UnicodeString& remove(int32_t start,
                               int32_t length = (int32_t)INT32_MAX);

  inline UnicodeString& removeBetween(int32_t start,
                                      int32_t limit = (int32_t)INT32_MAX);

  inline UnicodeString &retainBetween(int32_t start, int32_t limit = INT32_MAX);

  /* Length operations */

  UBool padLeading(int32_t targetLength,
                    char16_t padChar = 0x0020);

  UBool padTrailing(int32_t targetLength,
                     char16_t padChar = 0x0020);

  inline UBool truncate(int32_t targetLength);

  UnicodeString& trim(void);


  /* Miscellaneous operations */

  inline UnicodeString& reverse(void);

  inline UnicodeString& reverse(int32_t start,
             int32_t length);

  UnicodeString& toUpper(void);

  UnicodeString& toUpper(const Locale& locale);

  UnicodeString& toLower(void);

  UnicodeString& toLower(const Locale& locale);

#if !UCONFIG_NO_BREAK_ITERATION

  UnicodeString &toTitle(BreakIterator *titleIter);

  UnicodeString &toTitle(BreakIterator *titleIter, const Locale &locale);

  UnicodeString &toTitle(BreakIterator *titleIter, const Locale &locale, uint32_t options);

#endif

  UnicodeString &foldCase(uint32_t options=0 /*U_FOLD_CASE_DEFAULT*/);

  //========================================
  // Access to the internal buffer
  //========================================

  char16_t *getBuffer(int32_t minCapacity);

  void releaseBuffer(int32_t newLength=-1);

  inline const char16_t *getBuffer() const;

  const char16_t *getTerminatedBuffer();

  //========================================
  // Constructors
  //========================================

  inline UnicodeString();

  UnicodeString(int32_t capacity, UChar32 c, int32_t count);

  UNISTR_FROM_CHAR_EXPLICIT UnicodeString(char16_t ch);

  UNISTR_FROM_CHAR_EXPLICIT UnicodeString(UChar32 ch);

  UNISTR_FROM_STRING_EXPLICIT UnicodeString(const char16_t *text);

#if !U_CHAR16_IS_TYPEDEF

  UNISTR_FROM_STRING_EXPLICIT UnicodeString(const uint16_t *text) :
      UnicodeString(ConstChar16Ptr(text)) {}
#endif

#if U_SIZEOF_WCHAR_T==2 || defined(U_IN_DOXYGEN)

  UNISTR_FROM_STRING_EXPLICIT UnicodeString(const wchar_t *text) :
      UnicodeString(ConstChar16Ptr(text)) {}
#endif

  UNISTR_FROM_STRING_EXPLICIT inline UnicodeString(const std::nullptr_t text);

  UnicodeString(const char16_t *text,
        int32_t textLength);

#if !U_CHAR16_IS_TYPEDEF

  UnicodeString(const uint16_t *text, int32_t textLength) :
      UnicodeString(ConstChar16Ptr(text), textLength) {}
#endif

#if U_SIZEOF_WCHAR_T==2 || defined(U_IN_DOXYGEN)

  UnicodeString(const wchar_t *text, int32_t textLength) :
      UnicodeString(ConstChar16Ptr(text), textLength) {}
#endif

  inline UnicodeString(const std::nullptr_t text, int32_t textLength);

  UnicodeString(UBool isTerminated,
                ConstChar16Ptr text,
                int32_t textLength);

  UnicodeString(char16_t *buffer, int32_t buffLength, int32_t buffCapacity);

#if !U_CHAR16_IS_TYPEDEF

  UnicodeString(uint16_t *buffer, int32_t buffLength, int32_t buffCapacity) :
      UnicodeString(Char16Ptr(buffer), buffLength, buffCapacity) {}
#endif

#if U_SIZEOF_WCHAR_T==2 || defined(U_IN_DOXYGEN)

  UnicodeString(wchar_t *buffer, int32_t buffLength, int32_t buffCapacity) :
      UnicodeString(Char16Ptr(buffer), buffLength, buffCapacity) {}
#endif

  inline UnicodeString(std::nullptr_t buffer, int32_t buffLength, int32_t buffCapacity);

#if U_CHARSET_IS_UTF8 || !UCONFIG_NO_CONVERSION

  UNISTR_FROM_STRING_EXPLICIT UnicodeString(const char *codepageData);

  UnicodeString(const char *codepageData, int32_t dataLength);

#endif

#if !UCONFIG_NO_CONVERSION

  UnicodeString(const char *codepageData, const char *codepage);

  UnicodeString(const char *codepageData, int32_t dataLength, const char *codepage);

  UnicodeString(
        const char *src, int32_t srcLength,
        UConverter *cnv,
        UErrorCode &errorCode);

#endif

  UnicodeString(const char *src, int32_t textLength, enum EInvariant inv);


  UnicodeString(const UnicodeString& that);

  UnicodeString(UnicodeString &&src) noexcept;

  UnicodeString(const UnicodeString& src, int32_t srcStart);

  UnicodeString(const UnicodeString& src, int32_t srcStart, int32_t srcLength);

  virtual UnicodeString *clone() const override;

  virtual ~UnicodeString();

  static UnicodeString fromUTF8(StringPiece utf8);

  static UnicodeString fromUTF32(const UChar32 *utf32, int32_t length);

  /* Miscellaneous operations */

  UnicodeString unescape() const;

  UChar32 unescapeAt(int32_t &offset) const;

  static UClassID U_EXPORT2 getStaticClassID();

  virtual UClassID getDynamicClassID() const override;

  //========================================
  // Implementation methods
  //========================================

protected:
  virtual int32_t getLength() const override;

  virtual char16_t getCharAt(int32_t offset) const override;

  virtual UChar32 getChar32At(int32_t offset) const override;

private:
  // For char* constructors. Could be made public.
  UnicodeString &setToUTF8(StringPiece utf8);
  // For extract(char*).
  // We could make a toUTF8(target, capacity, errorCode) public but not
  // this version: New API will be cleaner if we make callers create substrings
  // rather than having start+length on every method,
  // and it should take a UErrorCode&.
  int32_t
  toUTF8(int32_t start, int32_t len,
         char *target, int32_t capacity) const;

  UBool doEquals(const UnicodeString &text, int32_t len) const;

  inline UBool
  doEqualsSubstring(int32_t start,
           int32_t length,
           const UnicodeString& srcText,
           int32_t srcStart,
           int32_t srcLength) const;

  UBool doEqualsSubstring(int32_t start,
           int32_t length,
           const char16_t *srcChars,
           int32_t srcStart,
           int32_t srcLength) const;

  inline int8_t
  doCompare(int32_t start,
           int32_t length,
           const UnicodeString& srcText,
           int32_t srcStart,
           int32_t srcLength) const;

  int8_t doCompare(int32_t start,
           int32_t length,
           const char16_t *srcChars,
           int32_t srcStart,
           int32_t srcLength) const;

  inline int8_t
  doCompareCodePointOrder(int32_t start,
                          int32_t length,
                          const UnicodeString& srcText,
                          int32_t srcStart,
                          int32_t srcLength) const;

  int8_t doCompareCodePointOrder(int32_t start,
                                 int32_t length,
                                 const char16_t *srcChars,
                                 int32_t srcStart,
                                 int32_t srcLength) const;

  inline int8_t
  doCaseCompare(int32_t start,
                int32_t length,
                const UnicodeString &srcText,
                int32_t srcStart,
                int32_t srcLength,
                uint32_t options) const;

  int8_t
  doCaseCompare(int32_t start,
                int32_t length,
                const char16_t *srcChars,
                int32_t srcStart,
                int32_t srcLength,
                uint32_t options) const;

  int32_t doIndexOf(char16_t c,
            int32_t start,
            int32_t length) const;

  int32_t doIndexOf(UChar32 c,
                        int32_t start,
                        int32_t length) const;

  int32_t doLastIndexOf(char16_t c,
                int32_t start,
                int32_t length) const;

  int32_t doLastIndexOf(UChar32 c,
                            int32_t start,
                            int32_t length) const;

  void doExtract(int32_t start,
         int32_t length,
         char16_t *dst,
         int32_t dstStart) const;

  inline void doExtract(int32_t start,
         int32_t length,
         UnicodeString& target) const;

  inline char16_t doCharAt(int32_t offset)  const;

  UnicodeString& doReplace(int32_t start,
               int32_t length,
               const UnicodeString& srcText,
               int32_t srcStart,
               int32_t srcLength);

  UnicodeString& doReplace(int32_t start,
               int32_t length,
               const char16_t *srcChars,
               int32_t srcStart,
               int32_t srcLength);

  UnicodeString& doAppend(const UnicodeString& src, int32_t srcStart, int32_t srcLength);
  UnicodeString& doAppend(const char16_t *srcChars, int32_t srcStart, int32_t srcLength);

  UnicodeString& doReverse(int32_t start,
               int32_t length);

  // calculate hash code
  int32_t doHashCode(void) const;

  // get pointer to start of array
  // these do not check for kOpenGetBuffer, unlike the public getBuffer() function
  inline char16_t* getArrayStart(void);
  inline const char16_t* getArrayStart(void) const;

  inline UBool hasShortLength() const;
  inline int32_t getShortLength() const;

  // A UnicodeString object (not necessarily its current buffer)
  // is writable unless it isBogus() or it has an "open" getBuffer(minCapacity).
  inline UBool isWritable() const;

  // Is the current buffer writable?
  inline UBool isBufferWritable() const;

  // None of the following does releaseArray().
  inline void setZeroLength();
  inline void setShortLength(int32_t len);
  inline void setLength(int32_t len);
  inline void setToEmpty();
  inline void setArray(char16_t *array, int32_t len, int32_t capacity); // sets length but not flags

  // allocate the array; result may be the stack buffer
  // sets refCount to 1 if appropriate
  // sets fArray, fCapacity, and flags
  // sets length to 0
  // returns boolean for success or failure
  UBool allocate(int32_t capacity);

  // release the array if owned
  void releaseArray(void);

  // turn a bogus string into an empty one
  void unBogus();

  // implements assignment operator, copy constructor, and fastCopyFrom()
  UnicodeString &copyFrom(const UnicodeString &src, UBool fastCopy=false);

  // Copies just the fields without memory management.
  void copyFieldsFrom(UnicodeString &src, UBool setSrcToBogus) noexcept;

  // Pin start and limit to acceptable values.
  inline void pinIndex(int32_t& start) const;
  inline void pinIndices(int32_t& start,
                         int32_t& length) const;

#if !UCONFIG_NO_CONVERSION

  /* Internal extract() using UConverter. */
  int32_t doExtract(int32_t start, int32_t length,
                    char *dest, int32_t destCapacity,
                    UConverter *cnv,
                    UErrorCode &errorCode) const;

  /*
   * Real constructor for converting from codepage data.
   * It assumes that it is called with !fRefCounted.
   *
   * If `codepage==0`, then the default converter
   * is used for the platform encoding.
   * If `codepage` is an empty string (`""`),
   * then a simple conversion is performed on the codepage-invariant
   * subset ("invariant characters") of the platform encoding. See utypes.h.
   */
  void doCodepageCreate(const char *codepageData,
                        int32_t dataLength,
                        const char *codepage);

  /*
   * Worker function for creating a UnicodeString from
   * a codepage string using a UConverter.
   */
  void
  doCodepageCreate(const char *codepageData,
                   int32_t dataLength,
                   UConverter *converter,
                   UErrorCode &status);

#endif

  /*
   * This function is called when write access to the array
   * is necessary.
   *
   * We need to make a copy of the array if
   * the buffer is read-only, or
   * the buffer is refCounted (shared), and refCount>1, or
   * the buffer is too small.
   *
   * Return false if memory could not be allocated.
   */
  UBool cloneArrayIfNeeded(int32_t newCapacity = -1,
                            int32_t growCapacity = -1,
                            UBool doCopyArray = true,
                            int32_t **pBufferToDelete = 0,
                            UBool forceClone = false);

  UnicodeString &
  caseMap(int32_t caseLocale, uint32_t options,
#if !UCONFIG_NO_BREAK_ITERATION
          BreakIterator *iter,
#endif
          UStringCaseMapper *stringCaseMapper);

  // ref counting
  void addRef(void);
  int32_t removeRef(void);
  int32_t refCount(void) const;

  // constants
  enum {
    US_STACKBUF_SIZE=(int32_t)(UNISTR_OBJECT_SIZE-sizeof(void *)-2)/U_SIZEOF_UCHAR,
    kInvalidUChar=0xffff, // U+FFFF returned by charAt(invalid index)
    kInvalidHashCode=0, // invalid hash code
    kEmptyHashCode=1, // hash code for empty string

    // bit flag values for fLengthAndFlags
    kIsBogus=1,         // this string is bogus, i.e., not valid or nullptr
    kUsingStackBuffer=2,// using fUnion.fStackFields instead of fUnion.fFields
    kRefCounted=4,      // there is a refCount field before the characters in fArray
    kBufferIsReadonly=8,// do not write to this buffer
    kOpenGetBuffer=16,  // getBuffer(minCapacity) was called (is "open"),
                        // and releaseBuffer(newLength) must be called
    kAllStorageFlags=0x1f,

    kLengthShift=5,     // remaining 11 bits for non-negative short length, or negative if long
    kLength1=1<<kLengthShift,
    kMaxShortLength=0x3ff,  // max non-negative short length (leaves top bit 0)
    kLengthIsLarge=0xffe0,  // short length < 0, real length is in fUnion.fFields.fLength

    // combined values for convenience
    kShortString=kUsingStackBuffer,
    kLongString=kRefCounted,
    kReadonlyAlias=kBufferIsReadonly,
    kWritableAlias=0
  };

  friend class UnicodeStringAppendable;

  union StackBufferOrFields;        // forward declaration necessary before friend declaration
  friend union StackBufferOrFields; // make US_STACKBUF_SIZE visible inside fUnion

  /*
   * The following are all the class fields that are stored
   * in each UnicodeString object.
   * Note that UnicodeString has virtual functions,
   * therefore there is an implicit vtable pointer
   * as the first real field.
   * The fields should be aligned such that no padding is necessary.
   * On 32-bit machines, the size should be 32 bytes,
   * on 64-bit machines (8-byte pointers), it should be 40 bytes.
   *
   * We use a hack to achieve this.
   *
   * With at least some compilers, each of the following is forced to
   * a multiple of sizeof(pointer) [the largest field base unit here is a data pointer],
   * rounded up with additional padding if the fields do not already fit that requirement:
   * - sizeof(class UnicodeString)
   * - offsetof(UnicodeString, fUnion)
   * - sizeof(fUnion)
   * - sizeof(fStackFields)
   *
   * We optimize for the longest possible internal buffer for short strings.
   * fUnion.fStackFields begins with 2 bytes for storage flags
   * and the length of relatively short strings,
   * followed by the buffer for short string contents.
   * There is no padding inside fStackFields.
   *
   * Heap-allocated and aliased strings use fUnion.fFields.
   * Both fStackFields and fFields must begin with the same fields for flags and short length,
   * that is, those must have the same memory offsets inside the object,
   * because the flags must be inspected in order to decide which half of fUnion is being used.
   * We assume that the compiler does not reorder the fields.
   *
   * (Padding at the end of fFields is ok:
   * As long as it is no larger than fStackFields, it is not wasted space.)
   *
   * For some of the history of the UnicodeString class fields layout, see
   * - ICU ticket #11551 "longer UnicodeString contents in stack buffer"
   * - ICU ticket #11336 "UnicodeString: recombine stack buffer arrays"
   * - ICU ticket #8322 "why is sizeof(UnicodeString)==48?"
   */
  // (implicit) *vtable;
  union StackBufferOrFields {
    // fStackFields is used iff (fLengthAndFlags&kUsingStackBuffer) else fFields is used.
    // Each struct of the union must begin with fLengthAndFlags.
    struct {
      int16_t fLengthAndFlags;          // bit fields: see constants above
      char16_t fBuffer[US_STACKBUF_SIZE];  // buffer for short strings
    } fStackFields;
    struct {
      int16_t fLengthAndFlags;          // bit fields: see constants above
      int32_t fLength;    // number of characters in fArray if >127; else undefined
      int32_t fCapacity;  // capacity of fArray (in char16_ts)
      // array pointer last to minimize padding for machines with P128 data model
      // or pointer sizes that are not a power of 2
      char16_t   *fArray;    // the Unicode data
    } fFields;
  } fUnion;
};

U_COMMON_API UnicodeString U_EXPORT2
operator+ (const UnicodeString &s1, const UnicodeString &s2);

//========================================
// Inline members
//========================================

//========================================
// Privates
//========================================

inline void
UnicodeString::pinIndex(int32_t& start) const
{
  // pin index
  if(start < 0) {
    start = 0;
  } else if(start > length()) {
    start = length();
  }
}

inline void
UnicodeString::pinIndices(int32_t& start,
                          int32_t& _length) const
{
  // pin indices
  int32_t len = length();
  if(start < 0) {
    start = 0;
  } else if(start > len) {
    start = len;
  }
  if(_length < 0) {
    _length = 0;
  } else if(_length > (len - start)) {
    _length = (len - start);
  }
}

inline char16_t*
UnicodeString::getArrayStart() {
  return (fUnion.fFields.fLengthAndFlags&kUsingStackBuffer) ?
    fUnion.fStackFields.fBuffer : fUnion.fFields.fArray;
}

inline const char16_t*
UnicodeString::getArrayStart() const {
  return (fUnion.fFields.fLengthAndFlags&kUsingStackBuffer) ?
    fUnion.fStackFields.fBuffer : fUnion.fFields.fArray;
}

//========================================
// Default constructor
//========================================

inline
UnicodeString::UnicodeString() {
  fUnion.fStackFields.fLengthAndFlags=kShortString;
}

inline UnicodeString::UnicodeString(const std::nullptr_t /*text*/) {
  fUnion.fStackFields.fLengthAndFlags=kShortString;
}

inline UnicodeString::UnicodeString(const std::nullptr_t /*text*/, int32_t /*length*/) {
  fUnion.fStackFields.fLengthAndFlags=kShortString;
}

inline UnicodeString::UnicodeString(std::nullptr_t /*buffer*/, int32_t /*buffLength*/, int32_t /*buffCapacity*/) {
  fUnion.fStackFields.fLengthAndFlags=kShortString;
}

//========================================
// Read-only implementation methods
//========================================
inline UBool
UnicodeString::hasShortLength() const {
  return fUnion.fFields.fLengthAndFlags>=0;
}

inline int32_t
UnicodeString::getShortLength() const {
  // fLengthAndFlags must be non-negative -> short length >= 0
  // and arithmetic or logical shift does not matter.
  return fUnion.fFields.fLengthAndFlags>>kLengthShift;
}

inline int32_t
UnicodeString::length() const {
  return hasShortLength() ? getShortLength() : fUnion.fFields.fLength;
}

inline int32_t
UnicodeString::getCapacity() const {
  return (fUnion.fFields.fLengthAndFlags&kUsingStackBuffer) ?
    US_STACKBUF_SIZE : fUnion.fFields.fCapacity;
}

inline int32_t
UnicodeString::hashCode() const
{ return doHashCode(); }

inline UBool
UnicodeString::isBogus() const
{ return (UBool)(fUnion.fFields.fLengthAndFlags & kIsBogus); }

inline UBool
UnicodeString::isWritable() const
{ return (UBool)!(fUnion.fFields.fLengthAndFlags&(kOpenGetBuffer|kIsBogus)); }

inline UBool
UnicodeString::isBufferWritable() const
{
  return (UBool)(
      !(fUnion.fFields.fLengthAndFlags&(kOpenGetBuffer|kIsBogus|kBufferIsReadonly)) &&
      (!(fUnion.fFields.fLengthAndFlags&kRefCounted) || refCount()==1));
}

inline const char16_t *
UnicodeString::getBuffer() const {
  if(fUnion.fFields.fLengthAndFlags&(kIsBogus|kOpenGetBuffer)) {
    return nullptr;
  } else if(fUnion.fFields.fLengthAndFlags&kUsingStackBuffer) {
    return fUnion.fStackFields.fBuffer;
  } else {
    return fUnion.fFields.fArray;
  }
}

//========================================
// Read-only alias methods
//========================================
inline int8_t
UnicodeString::doCompare(int32_t start,
              int32_t thisLength,
              const UnicodeString& srcText,
              int32_t srcStart,
              int32_t srcLength) const
{
  if(srcText.isBogus()) {
    return (int8_t)!isBogus(); // 0 if both are bogus, 1 otherwise
  } else {
    srcText.pinIndices(srcStart, srcLength);
    return doCompare(start, thisLength, srcText.getArrayStart(), srcStart, srcLength);
  }
}

inline UBool
UnicodeString::doEqualsSubstring(int32_t start,
              int32_t thisLength,
              const UnicodeString& srcText,
              int32_t srcStart,
              int32_t srcLength) const
{
  if(srcText.isBogus()) {
    return isBogus();
  } else {
    srcText.pinIndices(srcStart, srcLength);
    return !isBogus() && doEqualsSubstring(start, thisLength, srcText.getArrayStart(), srcStart, srcLength);
  }
}

inline bool
UnicodeString::operator== (const UnicodeString& text) const
{
  if(isBogus()) {
    return text.isBogus();
  } else {
    int32_t len = length(), textLength = text.length();
    return !text.isBogus() && len == textLength && doEquals(text, len);
  }
}

inline bool
UnicodeString::operator!= (const UnicodeString& text) const
{ return (! operator==(text)); }

inline UBool
UnicodeString::operator> (const UnicodeString& text) const
{ return doCompare(0, length(), text, 0, text.length()) == 1; }

inline UBool
UnicodeString::operator< (const UnicodeString& text) const
{ return doCompare(0, length(), text, 0, text.length()) == -1; }

inline UBool
UnicodeString::operator>= (const UnicodeString& text) const
{ return doCompare(0, length(), text, 0, text.length()) != -1; }

inline UBool
UnicodeString::operator<= (const UnicodeString& text) const
{ return doCompare(0, length(), text, 0, text.length()) != 1; }

inline int8_t
UnicodeString::compare(const UnicodeString& text) const
{ return doCompare(0, length(), text, 0, text.length()); }

inline int8_t
UnicodeString::compare(int32_t start,
               int32_t _length,
               const UnicodeString& srcText) const
{ return doCompare(start, _length, srcText, 0, srcText.length()); }

inline int8_t
UnicodeString::compare(ConstChar16Ptr srcChars,
               int32_t srcLength) const
{ return doCompare(0, length(), srcChars, 0, srcLength); }

inline int8_t
UnicodeString::compare(int32_t start,
               int32_t _length,
               const UnicodeString& srcText,
               int32_t srcStart,
               int32_t srcLength) const
{ return doCompare(start, _length, srcText, srcStart, srcLength); }

inline int8_t
UnicodeString::compare(int32_t start,
               int32_t _length,
               const char16_t *srcChars) const
{ return doCompare(start, _length, srcChars, 0, _length); }

inline int8_t
UnicodeString::compare(int32_t start,
               int32_t _length,
               const char16_t *srcChars,
               int32_t srcStart,
               int32_t srcLength) const
{ return doCompare(start, _length, srcChars, srcStart, srcLength); }

inline int8_t
UnicodeString::compareBetween(int32_t start,
                  int32_t limit,
                  const UnicodeString& srcText,
                  int32_t srcStart,
                  int32_t srcLimit) const
{ return doCompare(start, limit - start,
           srcText, srcStart, srcLimit - srcStart); }

inline int8_t
UnicodeString::doCompareCodePointOrder(int32_t start,
                                       int32_t thisLength,
                                       const UnicodeString& srcText,
                                       int32_t srcStart,
                                       int32_t srcLength) const
{
  if(srcText.isBogus()) {
    return (int8_t)!isBogus(); // 0 if both are bogus, 1 otherwise
  } else {
    srcText.pinIndices(srcStart, srcLength);
    return doCompareCodePointOrder(start, thisLength, srcText.getArrayStart(), srcStart, srcLength);
  }
}

inline int8_t
UnicodeString::compareCodePointOrder(const UnicodeString& text) const
{ return doCompareCodePointOrder(0, length(), text, 0, text.length()); }

inline int8_t
UnicodeString::compareCodePointOrder(int32_t start,
                                     int32_t _length,
                                     const UnicodeString& srcText) const
{ return doCompareCodePointOrder(start, _length, srcText, 0, srcText.length()); }

inline int8_t
UnicodeString::compareCodePointOrder(ConstChar16Ptr srcChars,
                                     int32_t srcLength) const
{ return doCompareCodePointOrder(0, length(), srcChars, 0, srcLength); }

inline int8_t
UnicodeString::compareCodePointOrder(int32_t start,
                                     int32_t _length,
                                     const UnicodeString& srcText,
                                     int32_t srcStart,
                                     int32_t srcLength) const
{ return doCompareCodePointOrder(start, _length, srcText, srcStart, srcLength); }

inline int8_t
UnicodeString::compareCodePointOrder(int32_t start,
                                     int32_t _length,
                                     const char16_t *srcChars) const
{ return doCompareCodePointOrder(start, _length, srcChars, 0, _length); }

inline int8_t
UnicodeString::compareCodePointOrder(int32_t start,
                                     int32_t _length,
                                     const char16_t *srcChars,
                                     int32_t srcStart,
                                     int32_t srcLength) const
{ return doCompareCodePointOrder(start, _length, srcChars, srcStart, srcLength); }

inline int8_t
UnicodeString::compareCodePointOrderBetween(int32_t start,
                                            int32_t limit,
                                            const UnicodeString& srcText,
                                            int32_t srcStart,
                                            int32_t srcLimit) const
{ return doCompareCodePointOrder(start, limit - start,
           srcText, srcStart, srcLimit - srcStart); }

inline int8_t
UnicodeString::doCaseCompare(int32_t start,
                             int32_t thisLength,
                             const UnicodeString &srcText,
                             int32_t srcStart,
                             int32_t srcLength,
                             uint32_t options) const
{
  if(srcText.isBogus()) {
    return (int8_t)!isBogus(); // 0 if both are bogus, 1 otherwise
  } else {
    srcText.pinIndices(srcStart, srcLength);
    return doCaseCompare(start, thisLength, srcText.getArrayStart(), srcStart, srcLength, options);
  }
}

inline int8_t
UnicodeString::caseCompare(const UnicodeString &text, uint32_t options) const {
  return doCaseCompare(0, length(), text, 0, text.length(), options);
}

inline int8_t
UnicodeString::caseCompare(int32_t start,
                           int32_t _length,
                           const UnicodeString &srcText,
                           uint32_t options) const {
  return doCaseCompare(start, _length, srcText, 0, srcText.length(), options);
}

inline int8_t
UnicodeString::caseCompare(ConstChar16Ptr srcChars,
                           int32_t srcLength,
                           uint32_t options) const {
  return doCaseCompare(0, length(), srcChars, 0, srcLength, options);
}

inline int8_t
UnicodeString::caseCompare(int32_t start,
                           int32_t _length,
                           const UnicodeString &srcText,
                           int32_t srcStart,
                           int32_t srcLength,
                           uint32_t options) const {
  return doCaseCompare(start, _length, srcText, srcStart, srcLength, options);
}

inline int8_t
UnicodeString::caseCompare(int32_t start,
                           int32_t _length,
                           const char16_t *srcChars,
                           uint32_t options) const {
  return doCaseCompare(start, _length, srcChars, 0, _length, options);
}

inline int8_t
UnicodeString::caseCompare(int32_t start,
                           int32_t _length,
                           const char16_t *srcChars,
                           int32_t srcStart,
                           int32_t srcLength,
                           uint32_t options) const {
  return doCaseCompare(start, _length, srcChars, srcStart, srcLength, options);
}

inline int8_t
UnicodeString::caseCompareBetween(int32_t start,
                                  int32_t limit,
                                  const UnicodeString &srcText,
                                  int32_t srcStart,
                                  int32_t srcLimit,
                                  uint32_t options) const {
  return doCaseCompare(start, limit - start, srcText, srcStart, srcLimit - srcStart, options);
}

inline int32_t
UnicodeString::indexOf(const UnicodeString& srcText,
               int32_t srcStart,
               int32_t srcLength,
               int32_t start,
               int32_t _length) const
{
  if(!srcText.isBogus()) {
    srcText.pinIndices(srcStart, srcLength);
    if(srcLength > 0) {
      return indexOf(srcText.getArrayStart(), srcStart, srcLength, start, _length);
    }
  }
  return -1;
}

inline int32_t
UnicodeString::indexOf(const UnicodeString& text) const
{ return indexOf(text, 0, text.length(), 0, length()); }

inline int32_t
UnicodeString::indexOf(const UnicodeString& text,
               int32_t start) const {
  pinIndex(start);
  return indexOf(text, 0, text.length(), start, length() - start);
}

inline int32_t
UnicodeString::indexOf(const UnicodeString& text,
               int32_t start,
               int32_t _length) const
{ return indexOf(text, 0, text.length(), start, _length); }

inline int32_t
UnicodeString::indexOf(const char16_t *srcChars,
               int32_t srcLength,
               int32_t start) const {
  pinIndex(start);
  return indexOf(srcChars, 0, srcLength, start, length() - start);
}

inline int32_t
UnicodeString::indexOf(ConstChar16Ptr srcChars,
               int32_t srcLength,
               int32_t start,
               int32_t _length) const
{ return indexOf(srcChars, 0, srcLength, start, _length); }

inline int32_t
UnicodeString::indexOf(char16_t c,
               int32_t start,
               int32_t _length) const
{ return doIndexOf(c, start, _length); }

inline int32_t
UnicodeString::indexOf(UChar32 c,
               int32_t start,
               int32_t _length) const
{ return doIndexOf(c, start, _length); }

inline int32_t
UnicodeString::indexOf(char16_t c) const
{ return doIndexOf(c, 0, length()); }

inline int32_t
UnicodeString::indexOf(UChar32 c) const
{ return indexOf(c, 0, length()); }

inline int32_t
UnicodeString::indexOf(char16_t c,
               int32_t start) const {
  pinIndex(start);
  return doIndexOf(c, start, length() - start);
}

inline int32_t
UnicodeString::indexOf(UChar32 c,
               int32_t start) const {
  pinIndex(start);
  return indexOf(c, start, length() - start);
}

inline int32_t
UnicodeString::lastIndexOf(ConstChar16Ptr srcChars,
               int32_t srcLength,
               int32_t start,
               int32_t _length) const
{ return lastIndexOf(srcChars, 0, srcLength, start, _length); }

inline int32_t
UnicodeString::lastIndexOf(const char16_t *srcChars,
               int32_t srcLength,
               int32_t start) const {
  pinIndex(start);
  return lastIndexOf(srcChars, 0, srcLength, start, length() - start);
}

inline int32_t
UnicodeString::lastIndexOf(const UnicodeString& srcText,
               int32_t srcStart,
               int32_t srcLength,
               int32_t start,
               int32_t _length) const
{
  if(!srcText.isBogus()) {
    srcText.pinIndices(srcStart, srcLength);
    if(srcLength > 0) {
      return lastIndexOf(srcText.getArrayStart(), srcStart, srcLength, start, _length);
    }
  }
  return -1;
}

inline int32_t
UnicodeString::lastIndexOf(const UnicodeString& text,
               int32_t start,
               int32_t _length) const
{ return lastIndexOf(text, 0, text.length(), start, _length); }

inline int32_t
UnicodeString::lastIndexOf(const UnicodeString& text,
               int32_t start) const {
  pinIndex(start);
  return lastIndexOf(text, 0, text.length(), start, length() - start);
}

inline int32_t
UnicodeString::lastIndexOf(const UnicodeString& text) const
{ return lastIndexOf(text, 0, text.length(), 0, length()); }

inline int32_t
UnicodeString::lastIndexOf(char16_t c,
               int32_t start,
               int32_t _length) const
{ return doLastIndexOf(c, start, _length); }

inline int32_t
UnicodeString::lastIndexOf(UChar32 c,
               int32_t start,
               int32_t _length) const {
  return doLastIndexOf(c, start, _length);
}

inline int32_t
UnicodeString::lastIndexOf(char16_t c) const
{ return doLastIndexOf(c, 0, length()); }

inline int32_t
UnicodeString::lastIndexOf(UChar32 c) const {
  return lastIndexOf(c, 0, length());
}

inline int32_t
UnicodeString::lastIndexOf(char16_t c,
               int32_t start) const {
  pinIndex(start);
  return doLastIndexOf(c, start, length() - start);
}

inline int32_t
UnicodeString::lastIndexOf(UChar32 c,
               int32_t start) const {
  pinIndex(start);
  return lastIndexOf(c, start, length() - start);
}

inline UBool
UnicodeString::startsWith(const UnicodeString& text) const
{ return doEqualsSubstring(0, text.length(), text, 0, text.length()); }

inline UBool
UnicodeString::startsWith(const UnicodeString& srcText,
              int32_t srcStart,
              int32_t srcLength) const
{ return doEqualsSubstring(0, srcLength, srcText, srcStart, srcLength); }

inline UBool
UnicodeString::startsWith(ConstChar16Ptr srcChars, int32_t srcLength) const {
  if(srcLength < 0) {
    srcLength = u_strlen(toUCharPtr(srcChars));
  }
  return doEqualsSubstring(0, srcLength, srcChars, 0, srcLength);
}

inline UBool
UnicodeString::startsWith(const char16_t *srcChars, int32_t srcStart, int32_t srcLength) const {
  if(srcLength < 0) {
    srcLength = u_strlen(toUCharPtr(srcChars));
  }
  return doEqualsSubstring(0, srcLength, srcChars, srcStart, srcLength);
}

inline UBool
UnicodeString::endsWith(const UnicodeString& text) const
{ return doEqualsSubstring(length() - text.length(), text.length(),
           text, 0, text.length()); }

inline UBool
UnicodeString::endsWith(const UnicodeString& srcText,
            int32_t srcStart,
            int32_t srcLength) const {
  srcText.pinIndices(srcStart, srcLength);
  return doEqualsSubstring(length() - srcLength, srcLength,
                   srcText, srcStart, srcLength);
}

inline UBool
UnicodeString::endsWith(ConstChar16Ptr srcChars,
            int32_t srcLength) const {
  if(srcLength < 0) {
    srcLength = u_strlen(toUCharPtr(srcChars));
  }
  return doEqualsSubstring(length() - srcLength, srcLength, srcChars, 0, srcLength);
}

inline UBool
UnicodeString::endsWith(const char16_t *srcChars,
            int32_t srcStart,
            int32_t srcLength) const {
  if(srcLength < 0) {
    srcLength = u_strlen(toUCharPtr(srcChars + srcStart));
  }
  return doEqualsSubstring(length() - srcLength, srcLength,
                   srcChars, srcStart, srcLength);
}

//========================================
// replace
//========================================
inline UnicodeString&
UnicodeString::replace(int32_t start,
               int32_t _length,
               const UnicodeString& srcText)
{ return doReplace(start, _length, srcText, 0, srcText.length()); }

inline UnicodeString&
UnicodeString::replace(int32_t start,
               int32_t _length,
               const UnicodeString& srcText,
               int32_t srcStart,
               int32_t srcLength)
{ return doReplace(start, _length, srcText, srcStart, srcLength); }

inline UnicodeString&
UnicodeString::replace(int32_t start,
               int32_t _length,
               ConstChar16Ptr srcChars,
               int32_t srcLength)
{ return doReplace(start, _length, srcChars, 0, srcLength); }

inline UnicodeString&
UnicodeString::replace(int32_t start,
               int32_t _length,
               const char16_t *srcChars,
               int32_t srcStart,
               int32_t srcLength)
{ return doReplace(start, _length, srcChars, srcStart, srcLength); }

inline UnicodeString&
UnicodeString::replace(int32_t start,
               int32_t _length,
               char16_t srcChar)
{ return doReplace(start, _length, &srcChar, 0, 1); }

inline UnicodeString&
UnicodeString::replaceBetween(int32_t start,
                  int32_t limit,
                  const UnicodeString& srcText)
{ return doReplace(start, limit - start, srcText, 0, srcText.length()); }

inline UnicodeString&
UnicodeString::replaceBetween(int32_t start,
                  int32_t limit,
                  const UnicodeString& srcText,
                  int32_t srcStart,
                  int32_t srcLimit)
{ return doReplace(start, limit - start, srcText, srcStart, srcLimit - srcStart); }

inline UnicodeString&
UnicodeString::findAndReplace(const UnicodeString& oldText,
                  const UnicodeString& newText)
{ return findAndReplace(0, length(), oldText, 0, oldText.length(),
            newText, 0, newText.length()); }

inline UnicodeString&
UnicodeString::findAndReplace(int32_t start,
                  int32_t _length,
                  const UnicodeString& oldText,
                  const UnicodeString& newText)
{ return findAndReplace(start, _length, oldText, 0, oldText.length(),
            newText, 0, newText.length()); }

// ============================
// extract
// ============================
inline void
UnicodeString::doExtract(int32_t start,
             int32_t _length,
             UnicodeString& target) const
{ target.replace(0, target.length(), *this, start, _length); }

inline void
UnicodeString::extract(int32_t start,
               int32_t _length,
               Char16Ptr target,
               int32_t targetStart) const
{ doExtract(start, _length, target, targetStart); }

inline void
UnicodeString::extract(int32_t start,
               int32_t _length,
               UnicodeString& target) const
{ doExtract(start, _length, target); }

#if !UCONFIG_NO_CONVERSION

inline int32_t
UnicodeString::extract(int32_t start,
               int32_t _length,
               char *dst,
               const char *codepage) const

{
  // This dstSize value will be checked explicitly
  return extract(start, _length, dst, dst!=0 ? 0xffffffff : 0, codepage);
}

#endif

inline void
UnicodeString::extractBetween(int32_t start,
                  int32_t limit,
                  char16_t *dst,
                  int32_t dstStart) const {
  pinIndex(start);
  pinIndex(limit);
  doExtract(start, limit - start, dst, dstStart);
}

inline UnicodeString
UnicodeString::tempSubStringBetween(int32_t start, int32_t limit) const {
    return tempSubString(start, limit - start);
}

inline char16_t
UnicodeString::doCharAt(int32_t offset) const
{
  if((uint32_t)offset < (uint32_t)length()) {
    return getArrayStart()[offset];
  } else {
    return kInvalidUChar;
  }
}

inline char16_t
UnicodeString::charAt(int32_t offset) const
{ return doCharAt(offset); }

inline char16_t
UnicodeString::operator[] (int32_t offset) const
{ return doCharAt(offset); }

inline UBool
UnicodeString::isEmpty() const {
  // Arithmetic or logical right shift does not matter: only testing for 0.
  return (fUnion.fFields.fLengthAndFlags>>kLengthShift) == 0;
}

//========================================
// Write implementation methods
//========================================
inline void
UnicodeString::setZeroLength() {
  fUnion.fFields.fLengthAndFlags &= kAllStorageFlags;
}

inline void
UnicodeString::setShortLength(int32_t len) {
  // requires 0 <= len <= kMaxShortLength
  fUnion.fFields.fLengthAndFlags =
    (int16_t)((fUnion.fFields.fLengthAndFlags & kAllStorageFlags) | (len << kLengthShift));
}

inline void
UnicodeString::setLength(int32_t len) {
  if(len <= kMaxShortLength) {
    setShortLength(len);
  } else {
    fUnion.fFields.fLengthAndFlags |= kLengthIsLarge;
    fUnion.fFields.fLength = len;
  }
}

inline void
UnicodeString::setToEmpty() {
  fUnion.fFields.fLengthAndFlags = kShortString;
}

inline void
UnicodeString::setArray(char16_t *array, int32_t len, int32_t capacity) {
  setLength(len);
  fUnion.fFields.fArray = array;
  fUnion.fFields.fCapacity = capacity;
}

inline UnicodeString&
UnicodeString::operator= (char16_t ch)
{ return doReplace(0, length(), &ch, 0, 1); }

inline UnicodeString&
UnicodeString::operator= (UChar32 ch)
{ return replace(0, length(), ch); }

inline UnicodeString&
UnicodeString::setTo(const UnicodeString& srcText,
             int32_t srcStart,
             int32_t srcLength)
{
  unBogus();
  return doReplace(0, length(), srcText, srcStart, srcLength);
}

inline UnicodeString&
UnicodeString::setTo(const UnicodeString& srcText,
             int32_t srcStart)
{
  unBogus();
  srcText.pinIndex(srcStart);
  return doReplace(0, length(), srcText, srcStart, srcText.length() - srcStart);
}

inline UnicodeString&
UnicodeString::setTo(const UnicodeString& srcText)
{
  return copyFrom(srcText);
}

inline UnicodeString&
UnicodeString::setTo(const char16_t *srcChars,
             int32_t srcLength)
{
  unBogus();
  return doReplace(0, length(), srcChars, 0, srcLength);
}

inline UnicodeString&
UnicodeString::setTo(char16_t srcChar)
{
  unBogus();
  return doReplace(0, length(), &srcChar, 0, 1);
}

inline UnicodeString&
UnicodeString::setTo(UChar32 srcChar)
{
  unBogus();
  return replace(0, length(), srcChar);
}

inline UnicodeString&
UnicodeString::append(const UnicodeString& srcText,
              int32_t srcStart,
              int32_t srcLength)
{ return doAppend(srcText, srcStart, srcLength); }

inline UnicodeString&
UnicodeString::append(const UnicodeString& srcText)
{ return doAppend(srcText, 0, srcText.length()); }

inline UnicodeString&
UnicodeString::append(const char16_t *srcChars,
              int32_t srcStart,
              int32_t srcLength)
{ return doAppend(srcChars, srcStart, srcLength); }

inline UnicodeString&
UnicodeString::append(ConstChar16Ptr srcChars,
              int32_t srcLength)
{ return doAppend(srcChars, 0, srcLength); }

inline UnicodeString&
UnicodeString::append(char16_t srcChar)
{ return doAppend(&srcChar, 0, 1); }

inline UnicodeString&
UnicodeString::operator+= (char16_t ch)
{ return doAppend(&ch, 0, 1); }

inline UnicodeString&
UnicodeString::operator+= (UChar32 ch) {
  return append(ch);
}

inline UnicodeString&
UnicodeString::operator+= (const UnicodeString& srcText)
{ return doAppend(srcText, 0, srcText.length()); }

inline UnicodeString&
UnicodeString::insert(int32_t start,
              const UnicodeString& srcText,
              int32_t srcStart,
              int32_t srcLength)
{ return doReplace(start, 0, srcText, srcStart, srcLength); }

inline UnicodeString&
UnicodeString::insert(int32_t start,
              const UnicodeString& srcText)
{ return doReplace(start, 0, srcText, 0, srcText.length()); }

inline UnicodeString&
UnicodeString::insert(int32_t start,
              const char16_t *srcChars,
              int32_t srcStart,
              int32_t srcLength)
{ return doReplace(start, 0, srcChars, srcStart, srcLength); }

inline UnicodeString&
UnicodeString::insert(int32_t start,
              ConstChar16Ptr srcChars,
              int32_t srcLength)
{ return doReplace(start, 0, srcChars, 0, srcLength); }

inline UnicodeString&
UnicodeString::insert(int32_t start,
              char16_t srcChar)
{ return doReplace(start, 0, &srcChar, 0, 1); }

inline UnicodeString&
UnicodeString::insert(int32_t start,
              UChar32 srcChar)
{ return replace(start, 0, srcChar); }


inline UnicodeString&
UnicodeString::remove()
{
  // remove() of a bogus string makes the string empty and non-bogus
  if(isBogus()) {
    setToEmpty();
  } else {
    setZeroLength();
  }
  return *this;
}

inline UnicodeString&
UnicodeString::remove(int32_t start,
             int32_t _length)
{
    if(start <= 0 && _length == INT32_MAX) {
        // remove(guaranteed everything) of a bogus string makes the string empty and non-bogus
        return remove();
    }
    return doReplace(start, _length, nullptr, 0, 0);
}

inline UnicodeString&
UnicodeString::removeBetween(int32_t start,
                int32_t limit)
{ return doReplace(start, limit - start, nullptr, 0, 0); }

inline UnicodeString &
UnicodeString::retainBetween(int32_t start, int32_t limit) {
  truncate(limit);
  return doReplace(0, start, nullptr, 0, 0);
}

inline UBool
UnicodeString::truncate(int32_t targetLength)
{
  if(isBogus() && targetLength == 0) {
    // truncate(0) of a bogus string makes the string empty and non-bogus
    unBogus();
    return false;
  } else if((uint32_t)targetLength < (uint32_t)length()) {
    setLength(targetLength);
    return true;
  } else {
    return false;
  }
}

inline UnicodeString&
UnicodeString::reverse()
{ return doReverse(0, length()); }

inline UnicodeString&
UnicodeString::reverse(int32_t start,
               int32_t _length)
{ return doReverse(start, _length); }

U_NAMESPACE_END

#endif /* U_SHOW_CPLUSPLUS_API */

#endif