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 /*

 **********************************************************************

 *   Copyright (C) 1998-2013, 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

 /**

  * \file 

  * \brief C++ API: Unicode String 

  */

 #include "unicode/utypes.h"

 #include "unicode/rep.h"

 #include "unicode/std_string.h"

 #include "unicode/stringpiece.h"

 #include "unicode/bytestream.h"

 #include "unicode/ucasemap.h"

 struct UConverter;          // unicode/ucnv.h

 class  StringThreadTest;

 #ifndef U_COMPARE_CODE_POINT_ORDER

 /* see also ustring.h and unorm.h */

 /**

  * Option bit for u_strCaseCompare, u_strcasecmp, unorm_compare, etc:

  * Compare strings in code point order instead of code unit order.

  * @stable ICU 2.2

  */

 #define U_COMPARE_CODE_POINT_ORDER  0x8000

 #endif

 #ifndef USTRING_H

 /**

  * \ingroup ustring_ustrlen

  */

 U_STABLE int32_t U_EXPORT2

 u_strlen(const UChar *s);

 #endif

 /**

  * \def U_STRING_CASE_MAPPER_DEFINED

  * @internal

  */

 #ifndef U_STRING_CASE_MAPPER_DEFINED

 #define U_STRING_CASE_MAPPER_DEFINED

 /**

  * Internal string case mapping function type.

  * @internal

  */

 typedef int32_t U_CALLCONV

 UStringCaseMapper(const UCaseMap *csm,

                   UChar *dest, int32_t destCapacity,

                   const UChar *src, int32_t srcLength,

                   UErrorCode *pErrorCode);

 #endif

 U_NAMESPACE_BEGIN

 class BreakIterator;        // unicode/brkiter.h

 class Locale;               // unicode/locid.h

 class StringCharacterIterator;

 class UnicodeStringAppendable;  // unicode/appendable.h

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

 /**

  * Constant to be used in the UnicodeString(char *, int32_t, EInvariant) constructor

  * which constructs a Unicode string from an invariant-character char * string.

  * About invariant characters see utypes.h.

  * This constructor has no runtime dependency on conversion code and is

  * therefore recommended over ones taking a charset name string

  * (where the empty string "" indicates invariant-character conversion).

  *

  * @stable ICU 3.2

  */

 #define US_INV icu::UnicodeString::kInvariant

 /**

  * Unicode String literals in C++.

  * Dependent on the platform properties, different UnicodeString

  * constructors should be used to create a UnicodeString object from

  * a string literal.

  * The macros are defined for maximum performance.

  * They work only for strings that contain "invariant characters", i.e.,

  * only latin letters, digits, and some punctuation.

  * See utypes.h for details.

  *

  * The string parameter must be a C string literal.

  * The length of the string, not including the terminating

  * <code>NUL</code>, must be specified as a constant.

  * The U_STRING_DECL macro should be invoked exactly once for one

  * such string variable before it is used.

  * @stable ICU 2.0

  */

 #if defined(U_DECLARE_UTF16)

 #   define UNICODE_STRING(cs, _length) icu::UnicodeString(TRUE, (const UChar *)U_DECLARE_UTF16(cs), _length)

 #elif U_SIZEOF_WCHAR_T==U_SIZEOF_UCHAR && (U_CHARSET_FAMILY==U_ASCII_FAMILY || (U_SIZEOF_UCHAR == 2 && defined(U_WCHAR_IS_UTF16)))

 #   define UNICODE_STRING(cs, _length) icu::UnicodeString(TRUE, (const UChar *)L ## cs, _length)

 #elif U_SIZEOF_UCHAR==1 && U_CHARSET_FAMILY==U_ASCII_FAMILY

 #   define UNICODE_STRING(cs, _length) icu::UnicodeString(TRUE, (const UChar *)cs, _length)

 #else

 #   define UNICODE_STRING(cs, _length) icu::UnicodeString(cs, _length, US_INV)

 #endif

 /**

  * Unicode String literals in C++.

  * Dependent on the platform properties, different UnicodeString

  * constructors should be used to create a UnicodeString object from

  * a string literal.

  * The macros are defined for improved performance.

  * They work only for strings that contain "invariant characters", i.e.,

  * only latin letters, digits, and some punctuation.

  * See utypes.h for details.

  *

  * The string parameter must be a C string literal.

  * @stable ICU 2.0

  */

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

 /**

  * \def UNISTR_FROM_CHAR_EXPLICIT

  * This can be defined to be empty or "explicit".

  * If explicit, then the UnicodeString(UChar) and UnicodeString(UChar32)

  * constructors are marked as explicit, preventing their inadvertent use.

  * @stable ICU 49

  */

 #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

 /**

  * \def UNISTR_FROM_STRING_EXPLICIT

  * This can be defined to be empty or "explicit".

  * If explicit, then the UnicodeString(const char *) and UnicodeString(const UChar *)

  * constructors are marked as explicit, preventing their inadvertent use.

  *

  * In particular, this helps prevent accidentally depending on ICU conversion code

  * by passing a string literal into an API with a const UnicodeString & parameter.

  * @stable ICU 49

  */

 #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

 /**

  * UnicodeString is a string class that stores Unicode characters directly and provides

  * similar functionality as the Java String and StringBuffer classes.

  * It is a concrete implementation of the abstract class Replaceable (for transliteration).

  *

  * The UnicodeString class is not suitable for subclassing.

  *

  * <p>For an overview of Unicode strings in C and C++ see the

  * <a href="http://icu-project.org/userguide/strings.html">User Guide Strings chapter</a>.</p>

  *

  * <p>In ICU, a Unicode string consists of 16-bit Unicode <em>code units</em>.

  * A Unicode character may be stored with either one code unit

  * (the most common case) or with a matched pair of special code units

  * ("surrogates"). The data type for code units is UChar. 

  * For single-character handling, a Unicode character code <em>point</em> is a value

  * in the range 0..0x10ffff. ICU uses the UChar32 type for code points.</p>

  *

  * <p>Indexes and offsets into and lengths of strings always count code units, not code points.

  * This is the same as with multi-byte char* strings in traditional string handling.

  * Operations on partial strings typically do not test for code point boundaries.

  * If necessary, the user needs to take care of such boundaries by testing for the code unit

  * values or by using functions like

  * UnicodeString::getChar32Start() and UnicodeString::getChar32Limit()

  * (or, in C, the equivalent macros U16_SET_CP_START() and U16_SET_CP_LIMIT(), see utf.h).</p>

  *

  * UnicodeString methods are more lenient with regard to input parameter values

  * than other ICU APIs. In particular:

  * - If indexes are out of bounds for a UnicodeString object

  *   (<0 or >length()) then they are "pinned" to the nearest boundary.

  * - If primitive string pointer values (e.g., const UChar * or char *)

  *   for input strings are NULL, then those input string parameters are treated

  *   as if they pointed to an empty string.

  *   However, this is <em>not</em> the case for char * parameters for charset names

  *   or other IDs.

  * - Most UnicodeString methods do not take a UErrorCode parameter because

  *   there are usually very few opportunities for failure other than a shortage

  *   of memory, error codes in low-level C++ string methods would be inconvenient,

  *   and the error code as the last parameter (ICU convention) would prevent

  *   the use of default parameter values.

  *   Instead, such methods set the UnicodeString into a "bogus" state

  *   (see isBogus()) if an error occurs.

  *

  * In string comparisons, two UnicodeString objects that are both "bogus"

  * compare equal (to be transitive and prevent endless loops in sorting),

  * and a "bogus" string compares less than any non-"bogus" one.

  *

  * Const UnicodeString methods are thread-safe. Multiple threads can use

  * const methods on the same UnicodeString object simultaneously,

  * but non-const methods must not be called concurrently (in multiple threads)

  * with any other (const or non-const) methods.

  *

  * Similarly, const UnicodeString & parameters are thread-safe.

  * One object may be passed in as such a parameter concurrently in multiple threads.

  * This includes the const UnicodeString & parameters for

  * copy construction, assignment, and cloning.

  *

  * <p>UnicodeString uses several storage methods.

  * String contents can be stored inside the UnicodeString object itself,

  * in an allocated and shared buffer, or in an outside buffer that is "aliased".

  * Most of this is done transparently, but careful aliasing in particular provides

  * significant performance improvements.

  * Also, the internal buffer is accessible via special functions.

  * For details see the

  * <a href="http://icu-project.org/userguide/strings.html">User Guide Strings chapter</a>.</p>

  *

  * @see utf.h

  * @see CharacterIterator

  * @stable ICU 2.0

  */

 class U_COMMON_API UnicodeString : public Replaceable

 {

 public:

   /**

    * Constant to be used in the UnicodeString(char *, int32_t, EInvariant) constructor

    * which constructs a Unicode string from an invariant-character char * string.

    * Use the macro US_INV instead of the full qualification for this value.

    *

    * @see US_INV

    * @stable ICU 3.2

    */

   enum EInvariant {

     /**

      * @see EInvariant

      * @stable ICU 3.2

      */

     kInvariant

   };

   //========================================

   // Read-only operations

   //========================================

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

   /**

    * Equality operator. Performs only bitwise comparison.

    * @param text The UnicodeString to compare to this one.

    * @return TRUE if <TT>text</TT> contains the same characters as this one,

    * FALSE otherwise.

    * @stable ICU 2.0

    */

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

   /**

    * Inequality operator. Performs only bitwise comparison.

    * @param text The UnicodeString to compare to this one.

    * @return FALSE if <TT>text</TT> contains the same characters as this one,

    * TRUE otherwise.

    * @stable ICU 2.0

    */

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

   /**

    * Greater than operator. Performs only bitwise comparison.

    * @param text The UnicodeString to compare to this one.

    * @return TRUE if the characters in this are bitwise

    * greater than the characters in <code>text</code>, FALSE otherwise

    * @stable ICU 2.0

    */

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

   /**

    * Less than operator. Performs only bitwise comparison.

    * @param text The UnicodeString to compare to this one.

    * @return TRUE if the characters in this are bitwise

    * less than the characters in <code>text</code>, FALSE otherwise

    * @stable ICU 2.0

    */

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

   /**

    * Greater than or equal operator. Performs only bitwise comparison.

    * @param text The UnicodeString to compare to this one.

    * @return TRUE if the characters in this are bitwise

    * greater than or equal to the characters in <code>text</code>, FALSE otherwise

    * @stable ICU 2.0

    */

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

   /**

    * Less than or equal operator. Performs only bitwise comparison.

    * @param text The UnicodeString to compare to this one.

    * @return TRUE if the characters in this are bitwise

    * less than or equal to the characters in <code>text</code>, FALSE otherwise

    * @stable ICU 2.0

    */

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

   /**

    * Compare the characters bitwise in this UnicodeString to

    * the characters in <code>text</code>.

    * @param text The UnicodeString to compare to this one.

    * @return The result of bitwise character comparison: 0 if this

    * contains the same characters as <code>text</code>, -1 if the characters in

    * this are bitwise less than the characters in <code>text</code>, +1 if the

    * characters in this are bitwise greater than the characters

    * in <code>text</code>.

    * @stable ICU 2.0

    */

   inline int8_t compare(const UnicodeString& text) const;

   /**

    * Compare the characters bitwise in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the characters

    * in the <b>entire string</b> <TT>text</TT>.

    * (The parameters "start" and "length" are not applied to the other text "text".)

    * @param start the offset at which the compare operation begins

    * @param length the number of characters of text to compare.

    * @param text the other text to be compared against this string.

    * @return The result of bitwise character comparison: 0 if this

    * contains the same characters as <code>text</code>, -1 if the characters in

    * this are bitwise less than the characters in <code>text</code>, +1 if the

    * characters in this are bitwise greater than the characters

    * in <code>text</code>.

    * @stable ICU 2.0

    */

   inline int8_t compare(int32_t start,

          int32_t length,

          const UnicodeString& text) const;

   /**

    * Compare the characters bitwise in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the characters

    * in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).

    * @param start the offset at which the compare operation begins

    * @param length the number of characters in this to compare.

    * @param srcText the text to be compared

    * @param srcStart the offset into <TT>srcText</TT> to start comparison

    * @param srcLength the number of characters in <TT>src</TT> to compare

    * @return The result of bitwise character comparison: 0 if this

    * contains the same characters as <code>srcText</code>, -1 if the characters in

    * this are bitwise less than the characters in <code>srcText</code>, +1 if the

    * characters in this are bitwise greater than the characters

    * in <code>srcText</code>.

    * @stable ICU 2.0

    */

    inline int8_t compare(int32_t start,

          int32_t length,

          const UnicodeString& srcText,

          int32_t srcStart,

          int32_t srcLength) const;

   /**

    * Compare the characters bitwise in this UnicodeString with the first

    * <TT>srcLength</TT> characters in <TT>srcChars</TT>.

    * @param srcChars The characters to compare to this UnicodeString.

    * @param srcLength the number of characters in <TT>srcChars</TT> to compare

    * @return The result of bitwise character comparison: 0 if this

    * contains the same characters as <code>srcChars</code>, -1 if the characters in

    * this are bitwise less than the characters in <code>srcChars</code>, +1 if the

    * characters in this are bitwise greater than the characters

    * in <code>srcChars</code>.

    * @stable ICU 2.0

    */

   inline int8_t compare(const UChar *srcChars,

          int32_t srcLength) const;

   /**

    * Compare the characters bitwise in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the first

    * <TT>length</TT> characters in <TT>srcChars</TT>

    * @param start the offset at which the compare operation begins

    * @param length the number of characters to compare.

    * @param srcChars the characters to be compared

    * @return The result of bitwise character comparison: 0 if this

    * contains the same characters as <code>srcChars</code>, -1 if the characters in

    * this are bitwise less than the characters in <code>srcChars</code>, +1 if the

    * characters in this are bitwise greater than the characters

    * in <code>srcChars</code>.

    * @stable ICU 2.0

    */

   inline int8_t compare(int32_t start,

          int32_t length,

          const UChar *srcChars) const;

   /**

    * Compare the characters bitwise in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the characters

    * in <TT>srcChars</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).

    * @param start the offset at which the compare operation begins

    * @param length the number of characters in this to compare

    * @param srcChars the characters to be compared

    * @param srcStart the offset into <TT>srcChars</TT> to start comparison

    * @param srcLength the number of characters in <TT>srcChars</TT> to compare

    * @return The result of bitwise character comparison: 0 if this

    * contains the same characters as <code>srcChars</code>, -1 if the characters in

    * this are bitwise less than the characters in <code>srcChars</code>, +1 if the

    * characters in this are bitwise greater than the characters

    * in <code>srcChars</code>.

    * @stable ICU 2.0

    */

   inline int8_t compare(int32_t start,

          int32_t length,

          const UChar *srcChars,

          int32_t srcStart,

          int32_t srcLength) const;

   /**

    * Compare the characters bitwise in the range

    * [<TT>start</TT>, <TT>limit</TT>) with the characters

    * in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcLimit</TT>).

    * @param start the offset at which the compare operation begins

    * @param limit the offset immediately following the compare operation

    * @param srcText the text to be compared

    * @param srcStart the offset into <TT>srcText</TT> to start comparison

    * @param srcLimit the offset into <TT>srcText</TT> to limit comparison

    * @return The result of bitwise character comparison: 0 if this

    * contains the same characters as <code>srcText</code>, -1 if the characters in

    * this are bitwise less than the characters in <code>srcText</code>, +1 if the

    * characters in this are bitwise greater than the characters

    * in <code>srcText</code>.

    * @stable ICU 2.0

    */

   inline int8_t compareBetween(int32_t start,

             int32_t limit,

             const UnicodeString& srcText,

             int32_t srcStart,

             int32_t srcLimit) const;

   /**

    * Compare two Unicode strings in code point order.

    * The result may be different from the results of compare(), operator<, etc.

    * if supplementary characters are present:

    *

    * In UTF-16, supplementary characters (with code points U+10000 and above) are

    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,

    * which means that they compare as less than some other BMP characters like U+feff.

    * This function compares Unicode strings in code point order.

    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.

    *

    * @param text Another string to compare this one to.

    * @return a negative/zero/positive integer corresponding to whether

    * this string is less than/equal to/greater than the second one

    * in code point order

    * @stable ICU 2.0

    */

   inline int8_t compareCodePointOrder(const UnicodeString& text) const;

   /**

    * Compare two Unicode strings in code point order.

    * The result may be different from the results of compare(), operator<, etc.

    * if supplementary characters are present:

    *

    * In UTF-16, supplementary characters (with code points U+10000 and above) are

    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,

    * which means that they compare as less than some other BMP characters like U+feff.

    * This function compares Unicode strings in code point order.

    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param length The number of code units from this string to compare.

    * @param srcText Another string to compare this one to.

    * @return a negative/zero/positive integer corresponding to whether

    * this string is less than/equal to/greater than the second one

    * in code point order

    * @stable ICU 2.0

    */

   inline int8_t compareCodePointOrder(int32_t start,

                                       int32_t length,

                                       const UnicodeString& srcText) const;

   /**

    * Compare two Unicode strings in code point order.

    * The result may be different from the results of compare(), operator<, etc.

    * if supplementary characters are present:

    *

    * In UTF-16, supplementary characters (with code points U+10000 and above) are

    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,

    * which means that they compare as less than some other BMP characters like U+feff.

    * This function compares Unicode strings in code point order.

    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param length The number of code units from this string to compare.

    * @param srcText Another string to compare this one to.

    * @param srcStart The start offset in that string at which the compare operation begins.

    * @param srcLength The number of code units from that string to compare.

    * @return a negative/zero/positive integer corresponding to whether

    * this string is less than/equal to/greater than the second one

    * in code point order

    * @stable ICU 2.0

    */

    inline int8_t compareCodePointOrder(int32_t start,

                                        int32_t length,

                                        const UnicodeString& srcText,

                                        int32_t srcStart,

                                        int32_t srcLength) const;

   /**

    * Compare two Unicode strings in code point order.

    * The result may be different from the results of compare(), operator<, etc.

    * if supplementary characters are present:

    *

    * In UTF-16, supplementary characters (with code points U+10000 and above) are

    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,

    * which means that they compare as less than some other BMP characters like U+feff.

    * This function compares Unicode strings in code point order.

    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.

    *

    * @param srcChars A pointer to another string to compare this one to.

    * @param srcLength The number of code units from that string to compare.

    * @return a negative/zero/positive integer corresponding to whether

    * this string is less than/equal to/greater than the second one

    * in code point order

    * @stable ICU 2.0

    */

   inline int8_t compareCodePointOrder(const UChar *srcChars,

                                       int32_t srcLength) const;

   /**

    * Compare two Unicode strings in code point order.

    * The result may be different from the results of compare(), operator<, etc.

    * if supplementary characters are present:

    *

    * In UTF-16, supplementary characters (with code points U+10000 and above) are

    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,

    * which means that they compare as less than some other BMP characters like U+feff.

    * This function compares Unicode strings in code point order.

    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param length The number of code units from this string to compare.

    * @param srcChars A pointer to another string to compare this one to.

    * @return a negative/zero/positive integer corresponding to whether

    * this string is less than/equal to/greater than the second one

    * in code point order

    * @stable ICU 2.0

    */

   inline int8_t compareCodePointOrder(int32_t start,

                                       int32_t length,

                                       const UChar *srcChars) const;

   /**

    * Compare two Unicode strings in code point order.

    * The result may be different from the results of compare(), operator<, etc.

    * if supplementary characters are present:

    *

    * In UTF-16, supplementary characters (with code points U+10000 and above) are

    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,

    * which means that they compare as less than some other BMP characters like U+feff.

    * This function compares Unicode strings in code point order.

    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param length The number of code units from this string to compare.

    * @param srcChars A pointer to another string to compare this one to.

    * @param srcStart The start offset in that string at which the compare operation begins.

    * @param srcLength The number of code units from that string to compare.

    * @return a negative/zero/positive integer corresponding to whether

    * this string is less than/equal to/greater than the second one

    * in code point order

    * @stable ICU 2.0

    */

   inline int8_t compareCodePointOrder(int32_t start,

                                       int32_t length,

                                       const UChar *srcChars,

                                       int32_t srcStart,

                                       int32_t srcLength) const;

   /**

    * Compare two Unicode strings in code point order.

    * The result may be different from the results of compare(), operator<, etc.

    * if supplementary characters are present:

    *

    * In UTF-16, supplementary characters (with code points U+10000 and above) are

    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,

    * which means that they compare as less than some other BMP characters like U+feff.

    * This function compares Unicode strings in code point order.

    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param limit The offset after the last code unit from this string to compare.

    * @param srcText Another string to compare this one to.

    * @param srcStart The start offset in that string at which the compare operation begins.

    * @param srcLimit The offset after the last code unit from that string to compare.

    * @return a negative/zero/positive integer corresponding to whether

    * this string is less than/equal to/greater than the second one

    * in code point order

    * @stable ICU 2.0

    */

   inline int8_t compareCodePointOrderBetween(int32_t start,

                                              int32_t limit,

                                              const UnicodeString& srcText,

                                              int32_t srcStart,

                                              int32_t srcLimit) const;

   /**

    * Compare two strings case-insensitively using full case folding.

    * This is equivalent to this->foldCase(options).compare(text.foldCase(options)).

    *

    * @param text Another string to compare this one to.

    * @param options A bit set of options:

    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:

    *     Comparison in code unit order with default case folding.

    *

    *   - U_COMPARE_CODE_POINT_ORDER

    *     Set to choose code point order instead of code unit order

    *     (see u_strCompare for details).

    *

    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I

    *

    * @return A negative, zero, or positive integer indicating the comparison result.

    * @stable ICU 2.0

    */

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

   /**

    * Compare two strings case-insensitively using full case folding.

    * This is equivalent to this->foldCase(options).compare(srcText.foldCase(options)).

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param length The number of code units from this string to compare.

    * @param srcText Another string to compare this one to.

    * @param options A bit set of options:

    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:

    *     Comparison in code unit order with default case folding.

    *

    *   - U_COMPARE_CODE_POINT_ORDER

    *     Set to choose code point order instead of code unit order

    *     (see u_strCompare for details).

    *

    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I

    *

    * @return A negative, zero, or positive integer indicating the comparison result.

    * @stable ICU 2.0

    */

   inline int8_t caseCompare(int32_t start,

          int32_t length,

          const UnicodeString& srcText,

          uint32_t options) const;

   /**

    * Compare two strings case-insensitively using full case folding.

    * This is equivalent to this->foldCase(options).compare(srcText.foldCase(options)).

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param length The number of code units from this string to compare.

    * @param srcText Another string to compare this one to.

    * @param srcStart The start offset in that string at which the compare operation begins.

    * @param srcLength The number of code units from that string to compare.

    * @param options A bit set of options:

    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:

    *     Comparison in code unit order with default case folding.

    *

    *   - U_COMPARE_CODE_POINT_ORDER

    *     Set to choose code point order instead of code unit order

    *     (see u_strCompare for details).

    *

    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I

    *

    * @return A negative, zero, or positive integer indicating the comparison result.

    * @stable ICU 2.0

    */

   inline int8_t caseCompare(int32_t start,

          int32_t length,

          const UnicodeString& srcText,

          int32_t srcStart,

          int32_t srcLength,

          uint32_t options) const;

   /**

    * Compare two strings case-insensitively using full case folding.

    * This is equivalent to this->foldCase(options).compare(srcChars.foldCase(options)).

    *

    * @param srcChars A pointer to another string to compare this one to.

    * @param srcLength The number of code units from that string to compare.

    * @param options A bit set of options:

    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:

    *     Comparison in code unit order with default case folding.

    *

    *   - U_COMPARE_CODE_POINT_ORDER

    *     Set to choose code point order instead of code unit order

    *     (see u_strCompare for details).

    *

    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I

    *

    * @return A negative, zero, or positive integer indicating the comparison result.

    * @stable ICU 2.0

    */

   inline int8_t caseCompare(const UChar *srcChars,

          int32_t srcLength,

          uint32_t options) const;

   /**

    * Compare two strings case-insensitively using full case folding.

    * This is equivalent to this->foldCase(options).compare(srcChars.foldCase(options)).

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param length The number of code units from this string to compare.

    * @param srcChars A pointer to another string to compare this one to.

    * @param options A bit set of options:

    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:

    *     Comparison in code unit order with default case folding.

    *

    *   - U_COMPARE_CODE_POINT_ORDER

    *     Set to choose code point order instead of code unit order

    *     (see u_strCompare for details).

    *

    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I

    *

    * @return A negative, zero, or positive integer indicating the comparison result.

    * @stable ICU 2.0

    */

   inline int8_t caseCompare(int32_t start,

          int32_t length,

          const UChar *srcChars,

          uint32_t options) const;

   /**

    * Compare two strings case-insensitively using full case folding.

    * This is equivalent to this->foldCase(options).compare(srcChars.foldCase(options)).

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param length The number of code units from this string to compare.

    * @param srcChars A pointer to another string to compare this one to.

    * @param srcStart The start offset in that string at which the compare operation begins.

    * @param srcLength The number of code units from that string to compare.

    * @param options A bit set of options:

    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:

    *     Comparison in code unit order with default case folding.

    *

    *   - U_COMPARE_CODE_POINT_ORDER

    *     Set to choose code point order instead of code unit order

    *     (see u_strCompare for details).

    *

    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I

    *

    * @return A negative, zero, or positive integer indicating the comparison result.

    * @stable ICU 2.0

    */

   inline int8_t caseCompare(int32_t start,

          int32_t length,

          const UChar *srcChars,

          int32_t srcStart,

          int32_t srcLength,

          uint32_t options) const;

   /**

    * Compare two strings case-insensitively using full case folding.

    * This is equivalent to this->foldCase(options).compareBetween(text.foldCase(options)).

    *

    * @param start The start offset in this string at which the compare operation begins.

    * @param limit The offset after the last code unit from this string to compare.

    * @param srcText Another string to compare this one to.

    * @param srcStart The start offset in that string at which the compare operation begins.

    * @param srcLimit The offset after the last code unit from that string to compare.

    * @param options A bit set of options:

    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:

    *     Comparison in code unit order with default case folding.

    *

    *   - U_COMPARE_CODE_POINT_ORDER

    *     Set to choose code point order instead of code unit order

    *     (see u_strCompare for details).

    *

    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I

    *

    * @return A negative, zero, or positive integer indicating the comparison result.

    * @stable ICU 2.0

    */

   inline int8_t caseCompareBetween(int32_t start,

             int32_t limit,

             const UnicodeString& srcText,

             int32_t srcStart,

             int32_t srcLimit,

             uint32_t options) const;

   /**

    * Determine if this starts with the characters in <TT>text</TT>

    * @param text The text to match.

    * @return TRUE if this starts with the characters in <TT>text</TT>,

    * FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool startsWith(const UnicodeString& text) const;

   /**

    * Determine if this starts with the characters in <TT>srcText</TT>

    * in the range [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).

    * @param srcText The text to match.

    * @param srcStart the offset into <TT>srcText</TT> to start matching

    * @param srcLength the number of characters in <TT>srcText</TT> to match

    * @return TRUE if this starts with the characters in <TT>text</TT>,

    * FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool startsWith(const UnicodeString& srcText,

             int32_t srcStart,

             int32_t srcLength) const;

   /**

    * Determine if this starts with the characters in <TT>srcChars</TT>

    * @param srcChars The characters to match.

    * @param srcLength the number of characters in <TT>srcChars</TT>

    * @return TRUE if this starts with the characters in <TT>srcChars</TT>,

    * FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool startsWith(const UChar *srcChars,

             int32_t srcLength) const;

   /**

    * Determine if this ends with the characters in <TT>srcChars</TT>

    * in the range  [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).

    * @param srcChars The characters to match.

    * @param srcStart the offset into <TT>srcText</TT> to start matching

    * @param srcLength the number of characters in <TT>srcChars</TT> to match

    * @return TRUE if this ends with the characters in <TT>srcChars</TT>, FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool startsWith(const UChar *srcChars,

             int32_t srcStart,

             int32_t srcLength) const;

   /**

    * Determine if this ends with the characters in <TT>text</TT>

    * @param text The text to match.

    * @return TRUE if this ends with the characters in <TT>text</TT>,

    * FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool endsWith(const UnicodeString& text) const;

   /**

    * Determine if this ends with the characters in <TT>srcText</TT>

    * in the range [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).

    * @param srcText The text to match.

    * @param srcStart the offset into <TT>srcText</TT> to start matching

    * @param srcLength the number of characters in <TT>srcText</TT> to match

    * @return TRUE if this ends with the characters in <TT>text</TT>,

    * FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool endsWith(const UnicodeString& srcText,

           int32_t srcStart,

           int32_t srcLength) const;

   /**

    * Determine if this ends with the characters in <TT>srcChars</TT>

    * @param srcChars The characters to match.

    * @param srcLength the number of characters in <TT>srcChars</TT>

    * @return TRUE if this ends with the characters in <TT>srcChars</TT>,

    * FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool endsWith(const UChar *srcChars,

           int32_t srcLength) const;

   /**

    * Determine if this ends with the characters in <TT>srcChars</TT>

    * in the range  [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).

    * @param srcChars The characters to match.

    * @param srcStart the offset into <TT>srcText</TT> to start matching

    * @param srcLength the number of characters in <TT>srcChars</TT> to match

    * @return TRUE if this ends with the characters in <TT>srcChars</TT>,

    * FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool endsWith(const UChar *srcChars,

           int32_t srcStart,

           int32_t srcLength) const;

   /* Searching - bitwise only */

   /**

    * Locate in this the first occurrence of the characters in <TT>text</TT>,

    * using bitwise comparison.

    * @param text The text to search for.

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(const UnicodeString& text) const;

   /**

    * Locate in this the first occurrence of the characters in <TT>text</TT>

    * starting at offset <TT>start</TT>, using bitwise comparison.

    * @param text The text to search for.

    * @param start The offset at which searching will start.

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(const UnicodeString& text,

               int32_t start) const;

   /**

    * Locate in this the first occurrence in the range

    * [<TT>start</TT>, <TT>start + length</TT>) of the characters

    * in <TT>text</TT>, using bitwise comparison.

    * @param text The text to search for.

    * @param start The offset at which searching will start.

    * @param length The number of characters to search

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(const UnicodeString& text,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the first occurrence in the range

    * [<TT>start</TT>, <TT>start + length</TT>) of the characters

    *  in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>),

    * using bitwise comparison.

    * @param srcText The text to search for.

    * @param srcStart the offset into <TT>srcText</TT> at which

    * to start matching

    * @param srcLength the number of characters in <TT>srcText</TT> to match

    * @param start the offset into this at which to start matching

    * @param length the number of characters in this to search

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(const UnicodeString& srcText,

               int32_t srcStart,

               int32_t srcLength,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the first occurrence of the characters in

    * <TT>srcChars</TT>

    * starting at offset <TT>start</TT>, using bitwise comparison.

    * @param srcChars The text to search for.

    * @param srcLength the number of characters in <TT>srcChars</TT> to match

    * @param start the offset into this at which to start matching

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(const UChar *srcChars,

               int32_t srcLength,

               int32_t start) const;

   /**

    * Locate in this the first occurrence in the range

    * [<TT>start</TT>, <TT>start + length</TT>) of the characters

    * in <TT>srcChars</TT>, using bitwise comparison.

    * @param srcChars The text to search for.

    * @param srcLength the number of characters in <TT>srcChars</TT>

    * @param start The offset at which searching will start.

    * @param length The number of characters to search

    * @return The offset into this of the start of <TT>srcChars</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(const UChar *srcChars,

               int32_t srcLength,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the first occurrence in the range

    * [<TT>start</TT>, <TT>start + length</TT>) of the characters

    * in <TT>srcChars</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>),

    * using bitwise comparison.

    * @param srcChars The text to search for.

    * @param srcStart the offset into <TT>srcChars</TT> at which

    * to start matching

    * @param srcLength the number of characters in <TT>srcChars</TT> to match

    * @param start the offset into this at which to start matching

    * @param length the number of characters in this to search

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   int32_t indexOf(const UChar *srcChars,

               int32_t srcStart,

               int32_t srcLength,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the first occurrence of the BMP code point <code>c</code>,

    * using bitwise comparison.

    * @param c The code unit to search for.

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(UChar c) const;

   /**

    * Locate in this the first occurrence of the code point <TT>c</TT>,

    * using bitwise comparison.

    *

    * @param c The code point to search for.

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(UChar32 c) const;

   /**

    * Locate in this the first occurrence of the BMP code point <code>c</code>,

    * starting at offset <TT>start</TT>, using bitwise comparison.

    * @param c The code unit to search for.

    * @param start The offset at which searching will start.

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(UChar c,

               int32_t start) const;

   /**

    * Locate in this the first occurrence of the code point <TT>c</TT>

    * starting at offset <TT>start</TT>, using bitwise comparison.

    *

    * @param c The code point to search for.

    * @param start The offset at which searching will start.

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(UChar32 c,

               int32_t start) const;

   /**

    * Locate in this the first occurrence of the BMP code point <code>c</code>

    * in the range [<TT>start</TT>, <TT>start + length</TT>),

    * using bitwise comparison.

    * @param c The code unit to search for.

    * @param start the offset into this at which to start matching

    * @param length the number of characters in this to search

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(UChar c,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the first occurrence of the code point <TT>c</TT>

    * in the range [<TT>start</TT>, <TT>start + length</TT>),

    * using bitwise comparison.

    *

    * @param c The code point to search for.

    * @param start the offset into this at which to start matching

    * @param length the number of characters in this to search

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t indexOf(UChar32 c,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the last occurrence of the characters in <TT>text</TT>,

    * using bitwise comparison.

    * @param text The text to search for.

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(const UnicodeString& text) const;

   /**

    * Locate in this the last occurrence of the characters in <TT>text</TT>

    * starting at offset <TT>start</TT>, using bitwise comparison.

    * @param text The text to search for.

    * @param start The offset at which searching will start.

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(const UnicodeString& text,

               int32_t start) const;

   /**

    * Locate in this the last occurrence in the range

    * [<TT>start</TT>, <TT>start + length</TT>) of the characters

    * in <TT>text</TT>, using bitwise comparison.

    * @param text The text to search for.

    * @param start The offset at which searching will start.

    * @param length The number of characters to search

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(const UnicodeString& text,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the last occurrence in the range

    * [<TT>start</TT>, <TT>start + length</TT>) of the characters

    * in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>),

    * using bitwise comparison.

    * @param srcText The text to search for.

    * @param srcStart the offset into <TT>srcText</TT> at which

    * to start matching

    * @param srcLength the number of characters in <TT>srcText</TT> to match

    * @param start the offset into this at which to start matching

    * @param length the number of characters in this to search

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(const UnicodeString& srcText,

               int32_t srcStart,

               int32_t srcLength,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the last occurrence of the characters in <TT>srcChars</TT>

    * starting at offset <TT>start</TT>, using bitwise comparison.

    * @param srcChars The text to search for.

    * @param srcLength the number of characters in <TT>srcChars</TT> to match

    * @param start the offset into this at which to start matching

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(const UChar *srcChars,

               int32_t srcLength,

               int32_t start) const;

   /**

    * Locate in this the last occurrence in the range

    * [<TT>start</TT>, <TT>start + length</TT>) of the characters

    * in <TT>srcChars</TT>, using bitwise comparison.

    * @param srcChars The text to search for.

    * @param srcLength the number of characters in <TT>srcChars</TT>

    * @param start The offset at which searching will start.

    * @param length The number of characters to search

    * @return The offset into this of the start of <TT>srcChars</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(const UChar *srcChars,

               int32_t srcLength,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the last occurrence in the range

    * [<TT>start</TT>, <TT>start + length</TT>) of the characters

    * in <TT>srcChars</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>),

    * using bitwise comparison.

    * @param srcChars The text to search for.

    * @param srcStart the offset into <TT>srcChars</TT> at which

    * to start matching

    * @param srcLength the number of characters in <TT>srcChars</TT> to match

    * @param start the offset into this at which to start matching

    * @param length the number of characters in this to search

    * @return The offset into this of the start of <TT>text</TT>,

    * or -1 if not found.

    * @stable ICU 2.0

    */

   int32_t lastIndexOf(const UChar *srcChars,

               int32_t srcStart,

               int32_t srcLength,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the last occurrence of the BMP code point <code>c</code>,

    * using bitwise comparison.

    * @param c The code unit to search for.

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(UChar c) const;

   /**

    * Locate in this the last occurrence of the code point <TT>c</TT>,

    * using bitwise comparison.

    *

    * @param c The code point to search for.

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(UChar32 c) const;

   /**

    * Locate in this the last occurrence of the BMP code point <code>c</code>

    * starting at offset <TT>start</TT>, using bitwise comparison.

    * @param c The code unit to search for.

    * @param start The offset at which searching will start.

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(UChar c,

               int32_t start) const;

   /**

    * Locate in this the last occurrence of the code point <TT>c</TT>

    * starting at offset <TT>start</TT>, using bitwise comparison.

    *

    * @param c The code point to search for.

    * @param start The offset at which searching will start.

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(UChar32 c,

               int32_t start) const;

   /**

    * Locate in this the last occurrence of the BMP code point <code>c</code>

    * in the range [<TT>start</TT>, <TT>start + length</TT>),

    * using bitwise comparison.

    * @param c The code unit to search for.

    * @param start the offset into this at which to start matching

    * @param length the number of characters in this to search

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(UChar c,

               int32_t start,

               int32_t length) const;

   /**

    * Locate in this the last occurrence of the code point <TT>c</TT>

    * in the range [<TT>start</TT>, <TT>start + length</TT>),

    * using bitwise comparison.

    *

    * @param c The code point to search for.

    * @param start the offset into this at which to start matching

    * @param length the number of characters in this to search

    * @return The offset into this of <TT>c</TT>, or -1 if not found.

    * @stable ICU 2.0

    */

   inline int32_t lastIndexOf(UChar32 c,

               int32_t start,

               int32_t length) const;

   /* Character access */

   /**

    * Return the code unit at offset <tt>offset</tt>.

    * If the offset is not valid (0..length()-1) then U+ffff is returned.

    * @param offset a valid offset into the text

    * @return the code unit at offset <tt>offset</tt>

    *         or 0xffff if the offset is not valid for this string

    * @stable ICU 2.0

    */

   inline UChar charAt(int32_t offset) const;

   /**

    * Return the code unit at offset <tt>offset</tt>.

    * If the offset is not valid (0..length()-1) then U+ffff is returned.

    * @param offset a valid offset into the text

    * @return the code unit at offset <tt>offset</tt>

    * @stable ICU 2.0

    */

   inline UChar operator[] (int32_t offset) const;

   /**

    * Return the code point that contains the code unit

    * at offset <tt>offset</tt>.

    * If the offset is not valid (0..length()-1) then U+ffff is returned.

    * @param offset a valid offset into the text

    * that indicates the text offset of any of the code units

    * that will be assembled into a code point (21-bit value) and returned

    * @return the code point of text at <tt>offset</tt>

    *         or 0xffff if the offset is not valid for this string

    * @stable ICU 2.0

    */

   UChar32 char32At(int32_t offset) const;

   /**

    * Adjust a random-access offset so that

    * it points to the beginning of a Unicode character.

    * The offset that is passed in points to

    * any code unit of a code point,

    * while the returned offset will point to the first code unit

    * of the same code point.

    * In UTF-16, if the input offset points to a second surrogate

    * of a surrogate pair, then the returned offset will point

    * to the first surrogate.

    * @param offset a valid offset into one code point of the text

    * @return offset of the first code unit of the same code point

    * @see U16_SET_CP_START

    * @stable ICU 2.0

    */

   int32_t getChar32Start(int32_t offset) const;

   /**

    * Adjust a random-access offset so that

    * it points behind a Unicode character.

    * The offset that is passed in points behind

    * any code unit of a code point,

    * while the returned offset will point behind the last code unit

    * of the same code point.

    * In UTF-16, if the input offset points behind the first surrogate

    * (i.e., to the second surrogate)

    * of a surrogate pair, then the returned offset will point

    * behind the second surrogate (i.e., to the first surrogate).

    * @param offset a valid offset after any code unit of a code point of the text

    * @return offset of the first code unit after the same code point

    * @see U16_SET_CP_LIMIT

    * @stable ICU 2.0

    */

   int32_t getChar32Limit(int32_t offset) const;

   /**

    * Move the code unit index along the string by delta code points.

    * Interpret the input index as a code unit-based offset into the string,

    * move the index forward or backward by delta code points, and

    * return the resulting index.

    * The input index should point to the first code unit of a code point,

    * if there is more than one.

    *

    * Both input and output indexes are code unit-based as for all

    * string indexes/offsets in ICU (and other libraries, like MBCS char*).

    * If delta<0 then the index is moved backward (toward the start of the string).

    * If delta>0 then the index is moved forward (toward the end of the string).

    *

    * This behaves like CharacterIterator::move32(delta, kCurrent).

    *

    * Behavior for out-of-bounds indexes:

    * <code>moveIndex32</code> pins the input index to 0..length(), i.e.,

    * if the input index<0 then it is pinned to 0;

    * if it is index>length() then it is pinned to length().

    * Afterwards, the index is moved by <code>delta</code> code points

    * forward or backward,

    * but no further backward than to 0 and no further forward than to length().

    * The resulting index return value will be in between 0 and length(), inclusively.

    *

    * Examples:

    * <pre>

    * // s has code points 'a' U+10000 'b' U+10ffff U+2029

    * UnicodeString s=UNICODE_STRING("a\\U00010000b\\U0010ffff\\u2029", 31).unescape();

    *

    * // initial index: position of U+10000

    * int32_t index=1;

    *

    * // the following examples will all result in index==4, position of U+10ffff

    *

    * // skip 2 code points from some position in the string

    * index=s.moveIndex32(index, 2); // skips U+10000 and 'b'

    *

    * // go to the 3rd code point from the start of s (0-based)

    * index=s.moveIndex32(0, 3); // skips 'a', U+10000, and 'b'

    *

    * // go to the next-to-last code point of s

    * index=s.moveIndex32(s.length(), -2); // backward-skips U+2029 and U+10ffff

    * </pre>

    *

    * @param index input code unit index

    * @param delta (signed) code point count to move the index forward or backward

    *        in the string

    * @return the resulting code unit index

    * @stable ICU 2.0

    */

   int32_t moveIndex32(int32_t index, int32_t delta) const;

   /* Substring extraction */

   /**

    * Copy the characters in the range

    * [<tt>start</tt>, <tt>start + length</tt>) into the array <tt>dst</tt>,

    * beginning at <tt>dstStart</tt>.

    * If the string aliases to <code>dst</code> itself as an external buffer,

    * then extract() will not copy the contents.

    *

    * @param start offset of first character which will be copied into the array

    * @param length the number of characters to extract

    * @param dst array in which to copy characters.  The length of <tt>dst</tt>

    * must be at least (<tt>dstStart + length</tt>).

    * @param dstStart the offset in <TT>dst</TT> where the first character

    * will be extracted

    * @stable ICU 2.0

    */

   inline void extract(int32_t start,

            int32_t length,

            UChar *dst,

            int32_t dstStart = 0) const;

   /**

    * Copy the contents of the string into dest.

    * This is a convenience function that

    * checks if there is enough space in dest,

    * extracts the entire string if possible,

    * and NUL-terminates dest if possible.

    *

    * If the string fits into dest but cannot be NUL-terminated

    * (length()==destCapacity) then the error code is set to U_STRING_NOT_TERMINATED_WARNING.

    * If the string itself does not fit into dest

    * (length()>destCapacity) then the error code is set to U_BUFFER_OVERFLOW_ERROR.

    *

    * If the string aliases to <code>dest</code> itself as an external buffer,

    * then extract() will not copy the contents.

    *

    * @param dest Destination string buffer.

    * @param destCapacity Number of UChars available at dest.

    * @param errorCode ICU error code.

    * @return length()

    * @stable ICU 2.0

    */

   int32_t

   extract(UChar *dest, int32_t destCapacity,

           UErrorCode &errorCode) const;

   /**

    * Copy the characters in the range

    * [<tt>start</tt>, <tt>start + length</tt>) into the  UnicodeString

    * <tt>target</tt>.

    * @param start offset of first character which will be copied

    * @param length the number of characters to extract

    * @param target UnicodeString into which to copy characters.

    * @return A reference to <TT>target</TT>

    * @stable ICU 2.0

    */

   inline void extract(int32_t start,

            int32_t length,

            UnicodeString& target) const;

   /**

    * Copy the characters in the range [<tt>start</tt>, <tt>limit</tt>)

    * into the array <tt>dst</tt>, beginning at <tt>dstStart</tt>.

    * @param start offset of first character which will be copied into the array

    * @param limit offset immediately following the last character to be copied

    * @param dst array in which to copy characters.  The length of <tt>dst</tt>

    * must be at least (<tt>dstStart + (limit - start)</tt>).

    * @param dstStart the offset in <TT>dst</TT> where the first character

    * will be extracted

    * @stable ICU 2.0

    */

   inline void extractBetween(int32_t start,

               int32_t limit,

               UChar *dst,

               int32_t dstStart = 0) const;

   /**

    * Copy the characters in the range [<tt>start</tt>, <tt>limit</tt>)

    * into the UnicodeString <tt>target</tt>.  Replaceable API.

    * @param start offset of first character which will be copied

    * @param limit offset immediately following the last character to be copied

    * @param target UnicodeString into which to copy characters.

    * @return A reference to <TT>target</TT>

    * @stable ICU 2.0

    */

   virtual void extractBetween(int32_t start,

               int32_t limit,

               UnicodeString& target) const;

   /**

    * Copy the characters in the range 

    * [<tt>start</TT>, <tt>start + length</TT>) into an array of characters.

    * All characters must be invariant (see utypes.h).

    * Use US_INV as the last, signature-distinguishing parameter.

    *

    * This function does not write any more than <code>targetLength</code>

    * characters but returns the length of the entire output string

    * so that one can allocate a larger buffer and call the function again

    * if necessary.

    * The output string is NUL-terminated if possible.

    *

    * @param start offset of first character which will be copied

    * @param startLength the number of characters to extract

    * @param target the target buffer for extraction, can be NULL

    *               if targetLength is 0

    * @param targetCapacity the length of the target buffer

    * @param inv Signature-distinguishing paramater, use US_INV.

    * @return the output string length, not including the terminating NUL

    * @stable ICU 3.2

    */

   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

   /**

    * Copy the characters in the range

    * [<tt>start</TT>, <tt>start + length</TT>) into an array of characters

    * in the platform's default codepage.

    * This function does not write any more than <code>targetLength</code>

    * characters but returns the length of the entire output string

    * so that one can allocate a larger buffer and call the function again

    * if necessary.

    * The output string is NUL-terminated if possible.

    *

    * @param start offset of first character which will be copied

    * @param startLength the number of characters to extract

    * @param target the target buffer for extraction

    * @param targetLength the length of the target buffer

    * If <TT>target</TT> is NULL, then the number of bytes required for

    * <TT>target</TT> is returned.

    * @return the output string length, not including the terminating NUL

    * @stable ICU 2.0

    */

   int32_t extract(int32_t start,

            int32_t startLength,

            char *target,

            uint32_t targetLength) const;

 #endif

 #if !UCONFIG_NO_CONVERSION

   /**

    * Copy the characters in the range

    * [<tt>start</TT>, <tt>start + length</TT>) into an array of characters

    * in a specified codepage.

    * The output string is NUL-terminated.

    *

    * Recommendation: For invariant-character strings use

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

    * because it avoids object code dependencies of UnicodeString on

    * the conversion code.

    *

    * @param start offset of first character which will be copied

    * @param startLength the number of characters to extract

    * @param target the target buffer for extraction

    * @param codepage the desired codepage for the characters.  0 has

    * the special meaning of the default codepage

    * If <code>codepage</code> is an empty string (<code>""</code>),

    * then a simple conversion is performed on the codepage-invariant

    * subset ("invariant characters") of the platform encoding. See utypes.h.

    * If <TT>target</TT> is NULL, then the number of bytes required for

    * <TT>target</TT> is returned. It is assumed that the target is big enough

    * to fit all of the characters.

    * @return the output string length, not including the terminating NUL

    * @stable ICU 2.0

    */

   inline int32_t extract(int32_t start,

                  int32_t startLength,

                  char *target,

                  const char *codepage = 0) const;

   /**

    * Copy the characters in the range

    * [<tt>start</TT>, <tt>start + length</TT>) into an array of characters

    * in a specified codepage.

    * This function does not write any more than <code>targetLength</code>

    * characters but returns the length of the entire output string

    * so that one can allocate a larger buffer and call the function again

    * if necessary.

    * The output string is NUL-terminated if possible.

    *

    * Recommendation: For invariant-character strings use

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

    * because it avoids object code dependencies of UnicodeString on

    * the conversion code.

    *

    * @param start offset of first character which will be copied

    * @param startLength the number of characters to extract

    * @param target the target buffer for extraction

    * @param targetLength the length of the target buffer

    * @param codepage the desired codepage for the characters.  0 has

    * the special meaning of the default codepage

    * If <code>codepage</code> is an empty string (<code>""</code>),

    * then a simple conversion is performed on the codepage-invariant

    * subset ("invariant characters") of the platform encoding. See utypes.h.

    * If <TT>target</TT> is NULL, then the number of bytes required for

    * <TT>target</TT> is returned.

    * @return the output string length, not including the terminating NUL

    * @stable ICU 2.0

    */

   int32_t extract(int32_t start,

            int32_t startLength,

            char *target,

            uint32_t targetLength,

            const char *codepage) const;

   /**

    * Convert the UnicodeString into a codepage string using an existing UConverter.

    * The output string is NUL-terminated if possible.

    *

    * This function avoids the overhead of opening and closing a converter if

    * multiple strings are extracted.

    *

    * @param dest destination string buffer, can be NULL if destCapacity==0

    * @param destCapacity the number of chars available at dest

    * @param cnv the converter object to be used (ucnv_resetFromUnicode() will be called),

    *        or NULL for the default converter

    * @param errorCode normal ICU error code

    * @return the length of the output string, not counting the terminating NUL;

    *         if the length is greater than destCapacity, then the string will not fit

    *         and a buffer of the indicated length would need to be passed in

    * @stable ICU 2.0

    */

   int32_t extract(char *dest, int32_t destCapacity,

                   UConverter *cnv,

                   UErrorCode &errorCode) const;

 #endif

   /**

    * Create a temporary substring for the specified range.

    * Unlike the substring constructor and setTo() functions,

    * the object returned here will be a read-only alias (using getBuffer())

    * rather than copying the text.

    * As a result, this substring operation is much faster but requires

    * that the original string not be modified or deleted during the lifetime

    * of the returned substring object.

    * @param start offset of the first character visible in the substring

    * @param length length of the substring

    * @return a read-only alias UnicodeString object for the substring

    * @stable ICU 4.4

    */

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

   /**

    * Create a temporary substring for the specified range.

    * Same as tempSubString(start, length) except that the substring range

    * is specified as a (start, limit) pair (with an exclusive limit index)

    * rather than a (start, length) pair.

    * @param start offset of the first character visible in the substring

    * @param limit offset immediately following the last character visible in the substring

    * @return a read-only alias UnicodeString object for the substring

    * @stable ICU 4.4

    */

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

   /**

    * Convert the UnicodeString to UTF-8 and write the result

    * to a ByteSink. This is called by toUTF8String().

    * Unpaired surrogates are replaced with U+FFFD.

    * Calls u_strToUTF8WithSub().

    *

    * @param sink A ByteSink to which the UTF-8 version of the string is written.

    *             sink.Flush() is called at the end.

    * @stable ICU 4.2

    * @see toUTF8String

    */

   void toUTF8(ByteSink &sink) const;

 #if U_HAVE_STD_STRING

   /**

    * Convert the UnicodeString to UTF-8 and append the result

    * to a standard string.

    * Unpaired surrogates are replaced with U+FFFD.

    * Calls toUTF8().

    *

    * @param result A standard string (or a compatible object)

    *        to which the UTF-8 version of the string is appended.

    * @return The string object.

    * @stable ICU 4.2

    * @see toUTF8

    */

   template<typename StringClass>

   StringClass &toUTF8String(StringClass &result) const {

     StringByteSink<StringClass> sbs(&result);

     toUTF8(sbs);

     return result;

   }

 #endif

   /**

    * Convert the UnicodeString to UTF-32.

    * Unpaired surrogates are replaced with U+FFFD.

    * Calls u_strToUTF32WithSub().

    *

    * @param utf32 destination string buffer, can be NULL if capacity==0

    * @param capacity the number of UChar32s available at utf32

    * @param errorCode Standard ICU error code. Its input value must

    *                  pass the U_SUCCESS() test, or else the function returns

    *                  immediately. Check for U_FAILURE() on output or use with

    *                  function chaining. (See User Guide for details.)

    * @return The length of the UTF-32 string.

    * @see fromUTF32

    * @stable ICU 4.2

    */

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

   /* Length operations */

   /**

    * Return the length of the UnicodeString object.

    * The length is the number of UChar code units are in the UnicodeString.

    * If you want the number of code points, please use countChar32().

    * @return the length of the UnicodeString object

    * @see countChar32

    * @stable ICU 2.0

    */

   inline int32_t length(void) const;

   /**

    * Count Unicode code points in the length UChar code units of the string.

    * A code point may occupy either one or two UChar code units.

    * Counting code points involves reading all code units.

    *

    * This functions is basically the inverse of moveIndex32().

    *

    * @param start the index of the first code unit to check

    * @param length the number of UChar code units to check

    * @return the number of code points in the specified code units

    * @see length

    * @stable ICU 2.0

    */

   int32_t

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

   /**

    * Check if the length UChar code units of the string

    * contain more Unicode code points than a certain number.

    * This is more efficient than counting all code points in this part of the string

    * and comparing that number with a threshold.

    * This function may not need to scan the string at all if the length

    * falls within a certain range, and

    * never needs to count more than 'number+1' code points.

    * Logically equivalent to (countChar32(start, length)>number).

    * A Unicode code point may occupy either one or two UChar code units.

    *

    * @param start the index of the first code unit to check (0 for the entire string)

    * @param length the number of UChar code units to check

    *               (use INT32_MAX for the entire string; remember that start/length

    *                values are pinned)

    * @param number The number of code points in the (sub)string is compared against

    *               the 'number' parameter.

    * @return Boolean value for whether the string contains more Unicode code points

    *         than 'number'. Same as (u_countChar32(s, length)>number).

    * @see countChar32

    * @see u_strHasMoreChar32Than

    * @stable ICU 2.4

    */

   UBool

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

   /**

    * Determine if this string is empty.

    * @return TRUE if this string contains 0 characters, FALSE otherwise.

    * @stable ICU 2.0

    */

   inline UBool isEmpty(void) const;

   /**

    * Return the capacity of the internal buffer of the UnicodeString object.

    * This is useful together with the getBuffer functions.

    * See there for details.

    *

    * @return the number of UChars available in the internal buffer

    * @see getBuffer

    * @stable ICU 2.0

    */

   inline int32_t getCapacity(void) const;

   /* Other operations */

   /**

    * Generate a hash code for this object.

    * @return The hash code of this UnicodeString.

    * @stable ICU 2.0

    */

   inline int32_t hashCode(void) const;

   /**

    * Determine if this object contains a valid string.

    * A bogus string has no value. It is different from an empty string,

    * although in both cases isEmpty() returns TRUE and length() returns 0.

    * setToBogus() and isBogus() can be used to indicate that no string value is available.

    * For a bogus string, getBuffer() and getTerminatedBuffer() return NULL, and

    * length() returns 0.

    *

    * @return TRUE if the string is bogus/invalid, FALSE otherwise

    * @see setToBogus()

    * @stable ICU 2.0

    */

   inline UBool isBogus(void) const;

   //========================================

   // Write operations

   //========================================

   /* Assignment operations */

   /**

    * Assignment operator.  Replace the characters in this UnicodeString

    * with the characters from <TT>srcText</TT>.

    * @param srcText The text containing the characters to replace

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString &operator=(const UnicodeString &srcText);

   /**

    * Almost the same as the assignment operator.

    * Replace the characters in this UnicodeString

    * with the characters from <code>srcText</code>.

    *

    * This function works the same as the assignment operator

    * for all strings except for ones that are readonly aliases.

    *

    * Starting with ICU 2.4, the assignment operator and the copy constructor

    * allocate a new buffer and copy the buffer contents even for readonly aliases.

    * This function implements the old, more efficient but less safe behavior

    * of making this string also a readonly alias to the same buffer.

    *

    * The fastCopyFrom function must be used only if it is known that the lifetime of

    * this UnicodeString does not exceed the lifetime of the aliased buffer

    * including its contents, for example for strings from resource bundles

    * or aliases to string constants.

    *

    * @param src The text containing the characters to replace.

    * @return a reference to this

    * @stable ICU 2.4

    */

   UnicodeString &fastCopyFrom(const UnicodeString &src);

   /**

    * Assignment operator.  Replace the characters in this UnicodeString

    * with the code unit <TT>ch</TT>.

    * @param ch the code unit to replace

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& operator= (UChar ch);

   /**

    * Assignment operator.  Replace the characters in this UnicodeString

    * with the code point <TT>ch</TT>.

    * @param ch the code point to replace

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& operator= (UChar32 ch);

   /**

    * Set the text in the UnicodeString object to the characters

    * in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcText.length()</TT>).

    * <TT>srcText</TT> is not modified.

    * @param srcText the source for the new characters

    * @param srcStart the offset into <TT>srcText</TT> where new characters

    * will be obtained

    * @return a reference to this

    * @stable ICU 2.2

    */

   inline UnicodeString& setTo(const UnicodeString& srcText,

                int32_t srcStart);

   /**

    * Set the text in the UnicodeString object to the characters

    * in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).

    * <TT>srcText</TT> is not modified.

    * @param srcText the source for the new characters

    * @param srcStart the offset into <TT>srcText</TT> where new characters

    * will be obtained

    * @param srcLength the number of characters in <TT>srcText</TT> in the

    * replace string.

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& setTo(const UnicodeString& srcText,

                int32_t srcStart,

                int32_t srcLength);

   /**

    * Set the text in the UnicodeString object to the characters in

    * <TT>srcText</TT>.

    * <TT>srcText</TT> is not modified.

    * @param srcText the source for the new characters

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& setTo(const UnicodeString& srcText);

   /**

    * Set the characters in the UnicodeString object to the characters

    * in <TT>srcChars</TT>. <TT>srcChars</TT> is not modified.

    * @param srcChars the source for the new characters

    * @param srcLength the number of Unicode characters in srcChars.

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& setTo(const UChar *srcChars,

                int32_t srcLength);

   /**

    * Set the characters in the UnicodeString object to the code unit

    * <TT>srcChar</TT>.

    * @param srcChar the code unit which becomes the UnicodeString's character

    * content

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString& setTo(UChar srcChar);

   /**

    * Set the characters in the UnicodeString object to the code point

    * <TT>srcChar</TT>.

    * @param srcChar the code point which becomes the UnicodeString's character

    * content

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString& setTo(UChar32 srcChar);

   /**

    * Aliasing setTo() function, analogous to the readonly-aliasing UChar* constructor.

    * The text will be used for the UnicodeString object, but

    * it will not be released when the UnicodeString is destroyed.

    * This has copy-on-write semantics:

    * When the string is modified, then the buffer is first copied into

    * newly allocated memory.

    * The aliased buffer is never modified.

    *

    * In an assignment to another UnicodeString, when using the copy constructor

    * or the assignment operator, the text will be copied.

    * When using fastCopyFrom(), the text will be aliased again,

    * so that both strings then alias the same readonly-text.

    *

    * @param isTerminated specifies if <code>text</code> is <code>NUL</code>-terminated.

    *                     This must be true if <code>textLength==-1</code>.

    * @param text The characters to alias for the UnicodeString.

    * @param textLength The number of Unicode characters in <code>text</code> to alias.

    *                   If -1, then this constructor will determine the length

    *                   by calling <code>u_strlen()</code>.

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString &setTo(UBool isTerminated,

                        const UChar *text,

                        int32_t textLength);

   /**

    * Aliasing setTo() function, analogous to the writable-aliasing UChar* constructor.

    * The text will be used for the UnicodeString object, but

    * it will not be released when the UnicodeString is destroyed.

    * This has write-through semantics:

    * For as long as the capacity of the buffer is sufficient, write operations

    * will directly affect the buffer. When more capacity is necessary, then

    * a new buffer will be allocated and the contents copied as with regularly

    * constructed strings.

    * In an assignment to another UnicodeString, the buffer will be copied.

    * The extract(UChar *dst) function detects whether the dst pointer is the same

    * as the string buffer itself and will in this case not copy the contents.

    *

    * @param buffer The characters to alias for the UnicodeString.

    * @param buffLength The number of Unicode characters in <code>buffer</code> to alias.

    * @param buffCapacity The size of <code>buffer</code> in UChars.

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString &setTo(UChar *buffer,

                        int32_t buffLength,

                        int32_t buffCapacity);

   /**

    * Make this UnicodeString object invalid.

    * The string will test TRUE with isBogus().

    *

    * A bogus string has no value. It is different from an empty string.

    * It can be used to indicate that no string value is available.

    * getBuffer() and getTerminatedBuffer() return NULL, and

    * length() returns 0.

    *

    * This utility function is used throughout the UnicodeString

    * implementation to indicate that a UnicodeString operation failed,

    * and may be used in other functions,

    * especially but not exclusively when such functions do not

    * take a UErrorCode for simplicity.

    *

    * The following methods, and no others, will clear a string object's bogus flag:

    * - remove()

    * - remove(0, INT32_MAX)

    * - truncate(0)

    * - operator=() (assignment operator)

    * - setTo(...)

    *

    * The simplest ways to turn a bogus string into an empty one

    * is to use the remove() function.

    * Examples for other functions that are equivalent to "set to empty string":

    * \code

    * if(s.isBogus()) {

    *   s.remove();           // set to an empty string (remove all), or

    *   s.remove(0, INT32_MAX); // set to an empty string (remove all), or

    *   s.truncate(0);        // set to an empty string (complete truncation), or

    *   s=UnicodeString();    // assign an empty string, or

    *   s.setTo((UChar32)-1); // set to a pseudo code point that is out of range, or

    *   static const UChar nul=0;

    *   s.setTo(&nul, 0);     // set to an empty C Unicode string

    * }

    * \endcode

    *

    * @see isBogus()

    * @stable ICU 2.0

    */

   void setToBogus();

   /**

    * Set the character at the specified offset to the specified character.

    * @param offset A valid offset into the text of the character to set

    * @param ch The new character

    * @return A reference to this

    * @stable ICU 2.0

    */

   UnicodeString& setCharAt(int32_t offset,

                UChar ch);

   /* Append operations */

   /**

    * Append operator. Append the code unit <TT>ch</TT> to the UnicodeString

    * object.

    * @param ch the code unit to be appended

    * @return a reference to this

    * @stable ICU 2.0

    */

  inline  UnicodeString& operator+= (UChar ch);

   /**

    * Append operator. Append the code point <TT>ch</TT> to the UnicodeString

    * object.

    * @param ch the code point to be appended

    * @return a reference to this

    * @stable ICU 2.0

    */

  inline  UnicodeString& operator+= (UChar32 ch);

   /**

    * Append operator. Append the characters in <TT>srcText</TT> to the

    * UnicodeString object. <TT>srcText</TT> is not modified.

    * @param srcText the source for the new characters

    * @return a reference to this

    * @stable ICU 2.0

    */

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

   /**

    * Append the characters

    * in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>) to the

    * UnicodeString object at offset <TT>start</TT>. <TT>srcText</TT>

    * is not modified.

    * @param srcText the source for the new characters

    * @param srcStart the offset into <TT>srcText</TT> where new characters

    * will be obtained

    * @param srcLength the number of characters in <TT>srcText</TT> in

    * the append string

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& append(const UnicodeString& srcText,

             int32_t srcStart,

             int32_t srcLength);

   /**

    * Append the characters in <TT>srcText</TT> to the UnicodeString object.

    * <TT>srcText</TT> is not modified.

    * @param srcText the source for the new characters

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& append(const UnicodeString& srcText);

   /**

    * Append the characters in <TT>srcChars</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>) to the UnicodeString

    * object at offset

    * <TT>start</TT>. <TT>srcChars</TT> is not modified.

    * @param srcChars the source for the new characters

    * @param srcStart the offset into <TT>srcChars</TT> where new characters

    * will be obtained

    * @param srcLength the number of characters in <TT>srcChars</TT> in

    *                  the append string; can be -1 if <TT>srcChars</TT> is NUL-terminated

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& append(const UChar *srcChars,

             int32_t srcStart,

             int32_t srcLength);

   /**

    * Append the characters in <TT>srcChars</TT> to the UnicodeString object

    * at offset <TT>start</TT>. <TT>srcChars</TT> is not modified.

    * @param srcChars the source for the new characters

    * @param srcLength the number of Unicode characters in <TT>srcChars</TT>;

    *                  can be -1 if <TT>srcChars</TT> is NUL-terminated

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& append(const UChar *srcChars,

             int32_t srcLength);

   /**

    * Append the code unit <TT>srcChar</TT> to the UnicodeString object.

    * @param srcChar the code unit to append

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& append(UChar srcChar);

   /**

    * Append the code point <TT>srcChar</TT> to the UnicodeString object.

    * @param srcChar the code point to append

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString& append(UChar32 srcChar);

   /* Insert operations */

   /**

    * Insert the characters in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>) into the UnicodeString

    * object at offset <TT>start</TT>. <TT>srcText</TT> is not modified.

    * @param start the offset where the insertion begins

    * @param srcText the source for the new characters

    * @param srcStart the offset into <TT>srcText</TT> where new characters

    * will be obtained

    * @param srcLength the number of characters in <TT>srcText</TT> in

    * the insert string

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& insert(int32_t start,

             const UnicodeString& srcText,

             int32_t srcStart,

             int32_t srcLength);

   /**

    * Insert the characters in <TT>srcText</TT> into the UnicodeString object

    * at offset <TT>start</TT>. <TT>srcText</TT> is not modified.

    * @param start the offset where the insertion begins

    * @param srcText the source for the new characters

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& insert(int32_t start,

             const UnicodeString& srcText);

   /**

    * Insert the characters in <TT>srcChars</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>) into the UnicodeString

    *  object at offset <TT>start</TT>. <TT>srcChars</TT> is not modified.

    * @param start the offset at which the insertion begins

    * @param srcChars the source for the new characters

    * @param srcStart the offset into <TT>srcChars</TT> where new characters

    * will be obtained

    * @param srcLength the number of characters in <TT>srcChars</TT>

    * in the insert string

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& insert(int32_t start,

             const UChar *srcChars,

             int32_t srcStart,

             int32_t srcLength);

   /**

    * Insert the characters in <TT>srcChars</TT> into the UnicodeString object

    * at offset <TT>start</TT>. <TT>srcChars</TT> is not modified.

    * @param start the offset where the insertion begins

    * @param srcChars the source for the new characters

    * @param srcLength the number of Unicode characters in srcChars.

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& insert(int32_t start,

             const UChar *srcChars,

             int32_t srcLength);

   /**

    * Insert the code unit <TT>srcChar</TT> into the UnicodeString object at

    * offset <TT>start</TT>.

    * @param start the offset at which the insertion occurs

    * @param srcChar the code unit to insert

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& insert(int32_t start,

             UChar srcChar);

   /**

    * Insert the code point <TT>srcChar</TT> into the UnicodeString object at

    * offset <TT>start</TT>.

    * @param start the offset at which the insertion occurs

    * @param srcChar the code point to insert

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& insert(int32_t start,

             UChar32 srcChar);

   /* Replace operations */

   /**

    * Replace the characters in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the characters in

    * <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).

    * <TT>srcText</TT> is not modified.

    * @param start the offset at which the replace operation begins

    * @param length the number of characters to replace. The character at

    * <TT>start + length</TT> is not modified.

    * @param srcText the source for the new characters

    * @param srcStart the offset into <TT>srcText</TT> where new characters

    * will be obtained

    * @param srcLength the number of characters in <TT>srcText</TT> in

    * the replace string

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString& replace(int32_t start,

              int32_t length,

              const UnicodeString& srcText,

              int32_t srcStart,

              int32_t srcLength);

   /**

    * Replace the characters in the range

    * [<TT>start</TT>, <TT>start + length</TT>)

    * with the characters in <TT>srcText</TT>.  <TT>srcText</TT> is

    *  not modified.

    * @param start the offset at which the replace operation begins

    * @param length the number of characters to replace. The character at

    * <TT>start + length</TT> is not modified.

    * @param srcText the source for the new characters

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString& replace(int32_t start,

              int32_t length,

              const UnicodeString& srcText);

   /**

    * Replace the characters in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the characters in

    * <TT>srcChars</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>). <TT>srcChars</TT>

    * is not modified.

    * @param start the offset at which the replace operation begins

    * @param length the number of characters to replace.  The character at

    * <TT>start + length</TT> is not modified.

    * @param srcChars the source for the new characters

    * @param srcStart the offset into <TT>srcChars</TT> where new characters

    * will be obtained

    * @param srcLength the number of characters in <TT>srcChars</TT>

    * in the replace string

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString& replace(int32_t start,

              int32_t length,

              const UChar *srcChars,

              int32_t srcStart,

              int32_t srcLength);

   /**

    * Replace the characters in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the characters in

    * <TT>srcChars</TT>.  <TT>srcChars</TT> is not modified.

    * @param start the offset at which the replace operation begins

    * @param length number of characters to replace.  The character at

    * <TT>start + length</TT> is not modified.

    * @param srcChars the source for the new characters

    * @param srcLength the number of Unicode characters in srcChars

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& replace(int32_t start,

              int32_t length,

              const UChar *srcChars,

              int32_t srcLength);

   /**

    * Replace the characters in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the code unit

    * <TT>srcChar</TT>.

    * @param start the offset at which the replace operation begins

    * @param length the number of characters to replace.  The character at

    * <TT>start + length</TT> is not modified.

    * @param srcChar the new code unit

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& replace(int32_t start,

              int32_t length,

              UChar srcChar);

   /**

    * Replace the characters in the range

    * [<TT>start</TT>, <TT>start + length</TT>) with the code point

    * <TT>srcChar</TT>.

    * @param start the offset at which the replace operation begins

    * @param length the number of characters to replace.  The character at

    * <TT>start + length</TT> is not modified.

    * @param srcChar the new code point

    * @return a reference to this

    * @stable ICU 2.0

    */

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

   /**

    * Replace the characters in the range [<TT>start</TT>, <TT>limit</TT>)

    * with the characters in <TT>srcText</TT>. <TT>srcText</TT> is not modified.

    * @param start the offset at which the replace operation begins

    * @param limit the offset immediately following the replace range

    * @param srcText the source for the new characters

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& replaceBetween(int32_t start,

                 int32_t limit,

                 const UnicodeString& srcText);

   /**

    * Replace the characters in the range [<TT>start</TT>, <TT>limit</TT>)

    * with the characters in <TT>srcText</TT> in the range

    * [<TT>srcStart</TT>, <TT>srcLimit</TT>). <TT>srcText</TT> is not modified.

    * @param start the offset at which the replace operation begins

    * @param limit the offset immediately following the replace range

    * @param srcText the source for the new characters

    * @param srcStart the offset into <TT>srcChars</TT> where new characters

    * will be obtained

    * @param srcLimit the offset immediately following the range to copy

    * in <TT>srcText</TT>

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& replaceBetween(int32_t start,

                 int32_t limit,

                 const UnicodeString& srcText,

                 int32_t srcStart,

                 int32_t srcLimit);

   /**

    * Replace a substring of this object with the given text.

    * @param start the beginning index, inclusive; <code>0 <= start

    * <= limit</code>.

    * @param limit the ending index, exclusive; <code>start <= limit

    * <= length()</code>.

    * @param text the text to replace characters <code>start</code>

    * to <code>limit - 1</code>

    * @stable ICU 2.0

    */

   virtual void handleReplaceBetween(int32_t start,

                                     int32_t limit,

                                     const UnicodeString& text);

   /**

    * Replaceable API

    * @return TRUE if it has MetaData

    * @stable ICU 2.4

    */

   virtual UBool hasMetaData() const;

   /**

    * Copy a substring of this object, retaining attribute (out-of-band)

    * information.  This method is used to duplicate or reorder substrings.

    * The destination index must not overlap the source range.

    *

    * @param start the beginning index, inclusive; <code>0 <= start <=

    * limit</code>.

    * @param limit the ending index, exclusive; <code>start <= limit <=

    * length()</code>.

    * @param dest the destination index.  The characters from

    * <code>start..limit-1</code> will be copied to <code>dest</code>.

    * Implementations of this method may assume that <code>dest <= start ||

    * dest >= limit</code>.

    * @stable ICU 2.0

    */

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

   /* Search and replace operations */

   /**

    * Replace all occurrences of characters in oldText with the characters

    * in newText

    * @param oldText the text containing the search text

    * @param newText the text containing the replacement text

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& findAndReplace(const UnicodeString& oldText,

                 const UnicodeString& newText);

   /**

    * Replace all occurrences of characters in oldText with characters

    * in newText

    * in the range [<TT>start</TT>, <TT>start + length</TT>).

    * @param start the start of the range in which replace will performed

    * @param length the length of the range in which replace will be performed

    * @param oldText the text containing the search text

    * @param newText the text containing the replacement text

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& findAndReplace(int32_t start,

                 int32_t length,

                 const UnicodeString& oldText,

                 const UnicodeString& newText);

   /**

    * Replace all occurrences of characters in oldText in the range

    * [<TT>oldStart</TT>, <TT>oldStart + oldLength</TT>) with the characters

    * in newText in the range

    * [<TT>newStart</TT>, <TT>newStart + newLength</TT>)

    * in the range [<TT>start</TT>, <TT>start + length</TT>).

    * @param start the start of the range in which replace will performed

    * @param length the length of the range in which replace will be performed

    * @param oldText the text containing the search text

    * @param oldStart the start of the search range in <TT>oldText</TT>

    * @param oldLength the length of the search range in <TT>oldText</TT>

    * @param newText the text containing the replacement text

    * @param newStart the start of the replacement range in <TT>newText</TT>

    * @param newLength the length of the replacement range in <TT>newText</TT>

    * @return a reference to this

    * @stable ICU 2.0

    */

   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 */

   /**

    * Remove all characters from the UnicodeString object.

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& remove(void);

   /**

    * Remove the characters in the range

    * [<TT>start</TT>, <TT>start + length</TT>) from the UnicodeString object.

    * @param start the offset of the first character to remove

    * @param length the number of characters to remove

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& remove(int32_t start,

                                int32_t length = (int32_t)INT32_MAX);

   /**

    * Remove the characters in the range

    * [<TT>start</TT>, <TT>limit</TT>) from the UnicodeString object.

    * @param start the offset of the first character to remove

    * @param limit the offset immediately following the range to remove

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& removeBetween(int32_t start,

                                       int32_t limit = (int32_t)INT32_MAX);

   /**

    * Retain only the characters in the range

    * [<code>start</code>, <code>limit</code>) from the UnicodeString object.

    * Removes characters before <code>start</code> and at and after <code>limit</code>.

    * @param start the offset of the first character to retain

    * @param limit the offset immediately following the range to retain

    * @return a reference to this

    * @stable ICU 4.4

    */

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

   /* Length operations */

   /**

    * Pad the start of this UnicodeString with the character <TT>padChar</TT>.

    * If the length of this UnicodeString is less than targetLength,

    * length() - targetLength copies of padChar will be added to the

    * beginning of this UnicodeString.

    * @param targetLength the desired length of the string

    * @param padChar the character to use for padding. Defaults to

    * space (U+0020)

    * @return TRUE if the text was padded, FALSE otherwise.

    * @stable ICU 2.0

    */

   UBool padLeading(int32_t targetLength,

                     UChar padChar = 0x0020);

   /**

    * Pad the end of this UnicodeString with the character <TT>padChar</TT>.

    * If the length of this UnicodeString is less than targetLength,

    * length() - targetLength copies of padChar will be added to the

    * end of this UnicodeString.

    * @param targetLength the desired length of the string

    * @param padChar the character to use for padding. Defaults to

    * space (U+0020)

    * @return TRUE if the text was padded, FALSE otherwise.

    * @stable ICU 2.0

    */

   UBool padTrailing(int32_t targetLength,

                      UChar padChar = 0x0020);

   /**

    * Truncate this UnicodeString to the <TT>targetLength</TT>.

    * @param targetLength the desired length of this UnicodeString.

    * @return TRUE if the text was truncated, FALSE otherwise

    * @stable ICU 2.0

    */

   inline UBool truncate(int32_t targetLength);

   /**

    * Trims leading and trailing whitespace from this UnicodeString.

    * @return a reference to this

    * @stable ICU 2.0

    */

   UnicodeString& trim(void);

   /* Miscellaneous operations */

   /**

    * Reverse this UnicodeString in place.

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& reverse(void);

   /**

    * Reverse the range [<TT>start</TT>, <TT>start + length</TT>) in

    * this UnicodeString.

    * @param start the start of the range to reverse

    * @param length the number of characters to to reverse

    * @return a reference to this

    * @stable ICU 2.0

    */

   inline UnicodeString& reverse(int32_t start,

              int32_t length);

   /**

    * Convert the characters in this to UPPER CASE following the conventions of

    * the default locale.

    * @return A reference to this.

    * @stable ICU 2.0

    */

   UnicodeString& toUpper(void);

   /**

    * Convert the characters in this to UPPER CASE following the conventions of

    * a specific locale.

    * @param locale The locale containing the conventions to use.

    * @return A reference to this.

    * @stable ICU 2.0

    */

   UnicodeString& toUpper(const Locale& locale);

   /**

    * Convert the characters in this to lower case following the conventions of

    * the default locale.

    * @return A reference to this.

    * @stable ICU 2.0

    */

   UnicodeString& toLower(void);

   /**

    * Convert the characters in this to lower case following the conventions of

    * a specific locale.

    * @param locale The locale containing the conventions to use.

    * @return A reference to this.

    * @stable ICU 2.0

    */

   UnicodeString& toLower(const Locale& locale);

 #if !UCONFIG_NO_BREAK_ITERATION

   /**

    * Titlecase this string, convenience function using the default locale.

    *

    * Casing is locale-dependent and context-sensitive.

    * Titlecasing uses a break iterator to find the first characters of words

    * that are to be titlecased. It titlecases those characters and lowercases

    * all others.

    *

    * The titlecase break iterator can be provided to customize for arbitrary

    * styles, using rules and dictionaries beyond the standard iterators.

    * It may be more efficient to always provide an iterator to avoid

    * opening and closing one for each string.

    * The standard titlecase iterator for the root locale implements the

    * algorithm of Unicode TR 21.

    *

    * This function uses only the setText(), first() and next() methods of the

    * provided break iterator.

    *

    * @param titleIter A break iterator to find the first characters of words

    *                  that are to be titlecased.

    *                  If none is provided (0), then a standard titlecase

    *                  break iterator is opened.

    *                  Otherwise the provided iterator is set to the string's text.

    * @return A reference to this.

    * @stable ICU 2.1

    */

   UnicodeString &toTitle(BreakIterator *titleIter);

   /**

    * Titlecase this string.

    *

    * Casing is locale-dependent and context-sensitive.

    * Titlecasing uses a break iterator to find the first characters of words

    * that are to be titlecased. It titlecases those characters and lowercases

    * all others.

    *

    * The titlecase break iterator can be provided to customize for arbitrary

    * styles, using rules and dictionaries beyond the standard iterators.

    * It may be more efficient to always provide an iterator to avoid

    * opening and closing one for each string.

    * The standard titlecase iterator for the root locale implements the

    * algorithm of Unicode TR 21.

    *

    * This function uses only the setText(), first() and next() methods of the