/* vim:set ts=2 sw=2 et cindent: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla.
 *
 * The Initial Developer of the Original Code is IBM Corporation.
 * Portions created by IBM Corporation are Copyright (C) 2003
 * IBM Corporation.  All Rights Reserved.
 *
 * Contributor(s):
 *   Darin Fisher <darin@meer.net>
 *   Benjamin Smedberg <benjamin@smedbergs.us>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/**
 * This header provides wrapper classes around the frozen string API
 * which are roughly equivalent to the internal string classes.
 */

#ifdef MOZILLA_INTERNAL_API
#error nsStringAPI.h is only usable from non-MOZILLA_INTERNAL_API code!
#endif

#ifndef nsStringAPI_h__
#define nsStringAPI_h__

#include "nsXPCOMStrings.h"

class NS_COM_GLUE nsAString
{
public:
  typedef PRUnichar  char_type;
  typedef nsAString  self_type;
  typedef PRUint32   size_type;
  typedef PRUint32   index_type;

  /**
   * Returns the length, beginning, and end of a string in one operation.
   */
  PRUint32 BeginReading(const char_type **begin,
                        const char_type **end = nsnull) const;

  const char_type* BeginReading() const;
  const char_type* EndReading() const;

  /**
   * Get the length, begin writing, and optionally set the length of a
   * string all in one operation.
   *
   * @param   newSize Size the string to this length. Pass PR_UINT32_MAX
   *                  to leave the length unchanged.
   * @return  The new length of the string, or 0 if resizing failed.
   */
  PRUint32 BeginWriting(char_type **begin,
                        char_type **end = nsnull,
                        PRUint32 newSize = PR_UINT32_MAX);

  char_type* BeginWriting();
  char_type* EndWriting();

  PRBool SetLength(PRUint32 aLen);

  NS_HIDDEN_(size_type) Length() const
  {
    const char_type* data;
    return NS_StringGetData(*this, &data);
  }

  NS_HIDDEN_(PRBool) IsEmpty() const
  {
    return Length() == 0;
  }

  NS_HIDDEN_(void) Assign(const self_type& aString)
  {
    NS_StringCopy(*this, aString);
  }
  NS_HIDDEN_(void) Assign(const char_type* aData, size_type aLength = PR_UINT32_MAX)
  {
    NS_StringSetData(*this, aData, aLength);
  }
  NS_HIDDEN_(void) Assign(char_type aChar)
  {
    NS_StringSetData(*this, &aChar, 1);
  }

  NS_HIDDEN_(self_type&) operator=(const self_type& aString) { Assign(aString);   return *this; }
  NS_HIDDEN_(self_type&) operator=(const char_type* aPtr)    { Assign(aPtr);      return *this; }
  NS_HIDDEN_(self_type&) operator=(char_type aChar)          { Assign(aChar);     return *this; }

  NS_HIDDEN_(void) Replace( index_type cutStart, size_type cutLength, const char_type* data, size_type length = size_type(-1) )
  {
    NS_StringSetDataRange(*this, cutStart, cutLength, data, length);
  }
  NS_HIDDEN_(void) Replace( index_type cutStart, size_type cutLength, char_type c )
  {
    Replace(cutStart, cutLength, &c, 1);
  }
  NS_HIDDEN_(void) Replace( index_type cutStart, size_type cutLength, const self_type& readable )
  {
    const char_type* data;
    PRUint32 dataLen = NS_StringGetData(readable, &data);
    NS_StringSetDataRange(*this, cutStart, cutLength, data, dataLen);
  }

  NS_HIDDEN_(void) Append( char_type c )                                                              { Replace(size_type(-1), 0, c); }
  NS_HIDDEN_(void) Append( const char_type* data, size_type length = size_type(-1) )                  { Replace(size_type(-1), 0, data, length); }
  NS_HIDDEN_(void) Append( const self_type& readable )                                                { Replace(size_type(-1), 0, readable); }

  NS_HIDDEN_(self_type&) operator+=( char_type c )                                                    { Append(c);        return *this; }
  NS_HIDDEN_(self_type&) operator+=( const char_type* data )                                          { Append(data);     return *this; }
  NS_HIDDEN_(self_type&) operator+=( const self_type& readable )                                      { Append(readable); return *this; }

  NS_HIDDEN_(void) Insert( char_type c, index_type pos )                                              { Replace(pos, 0, c); }
  NS_HIDDEN_(void) Insert( const char_type* data, index_type pos, size_type length = size_type(-1) )  { Replace(pos, 0, data, length); }
  NS_HIDDEN_(void) Insert( const self_type& readable, index_type pos )                                { Replace(pos, 0, readable); }

  NS_HIDDEN_(void) Cut( index_type cutStart, size_type cutLength )                                    { Replace(cutStart, cutLength, nsnull, 0); }

  NS_HIDDEN_(void) Truncate() { SetLength(0); }

  /**
   * Compare strings of characters. Return 0 if the characters are equal,
   */
  typedef PRInt32 (*ComparatorFunc)(const char_type *a,
                                    const char_type *b,
                                    PRUint32 length);

  static PRInt32 DefaultComparator(const char_type *a,
                                   const char_type *b,
                                   PRUint32 length);

  PRBool Equals( const self_type &other,
                 ComparatorFunc c = DefaultComparator ) const;

protected:
  // Prevent people from allocating a nsAString directly.
  ~nsAString() {}
};

class NS_COM_GLUE nsACString
{
public:
  typedef char       char_type;
  typedef nsACString self_type;
  typedef PRUint32   size_type;
  typedef PRUint32   index_type;

  /**
   * Returns the length, beginning, and end of a string in one operation.
   */
  PRUint32 BeginReading(const char_type **begin,
                        const char_type **end = nsnull) const;

  const char_type* BeginReading() const;
  const char_type* EndReading() const;

  /**
   * Get the length, begin writing, and optionally set the length of a
   * string all in one operation.
   *
   * @param   newSize Size the string to this length. Pass PR_UINT32_MAX
   *                  to leave the length unchanged.
   * @return  The new length of the string, or 0 if resizing failed.
   */
  PRUint32 BeginWriting(char_type **begin,
                        char_type **end = nsnull,
                        PRUint32 newSize = PR_UINT32_MAX);

  char_type* BeginWriting();
  char_type* EndWriting();

  PRBool SetLength(PRUint32 aLen);

  NS_HIDDEN_(size_type) Length() const
  {
    const char_type* data;
    return NS_CStringGetData(*this, &data);
  }

  NS_HIDDEN_(PRBool) IsEmpty() const
  {
    return Length() == 0;
  }

  NS_HIDDEN_(void) Assign(const self_type& aString)
  {
    NS_CStringCopy(*this, aString);
  }
  NS_HIDDEN_(void) Assign(const char_type* aData, size_type aLength = PR_UINT32_MAX)
  {
    NS_CStringSetData(*this, aData, aLength);
  }
  NS_HIDDEN_(void) Assign(char_type aChar)
  {
    NS_CStringSetData(*this, &aChar, 1);
  }

  NS_HIDDEN_(self_type&) operator=(const self_type& aString) { Assign(aString);   return *this; }
  NS_HIDDEN_(self_type&) operator=(const char_type* aPtr)    { Assign(aPtr);      return *this; }
  NS_HIDDEN_(self_type&) operator=(char_type aChar)          { Assign(aChar);     return *this; }

  NS_HIDDEN_(void) Replace( index_type cutStart, size_type cutLength, const char_type* data, size_type length = size_type(-1) )
  {
    NS_CStringSetDataRange(*this, cutStart, cutLength, data, length);
  }
  NS_HIDDEN_(void) Replace( index_type cutStart, size_type cutLength, char_type c )
  {
    Replace(cutStart, cutLength, &c, 1);
  }
  NS_HIDDEN_(void) Replace( index_type cutStart, size_type cutLength, const self_type& readable )
  {
    const char_type* data;
    PRUint32 dataLen = NS_CStringGetData(readable, &data);
    NS_CStringSetDataRange(*this, cutStart, cutLength, data, dataLen);
  }

  NS_HIDDEN_(void) Append( char_type c )                                                              { Replace(size_type(-1), 0, c); }
  NS_HIDDEN_(void) Append( const char_type* data, size_type length = size_type(-1) )                  { Replace(size_type(-1), 0, data, length); }
  NS_HIDDEN_(void) Append( const self_type& readable )                                                { Replace(size_type(-1), 0, readable); }

  NS_HIDDEN_(self_type&) operator+=( char_type c )                                                    { Append(c);        return *this; }
  NS_HIDDEN_(self_type&) operator+=( const char_type* data )                                          { Append(data);     return *this; }
  NS_HIDDEN_(self_type&) operator+=( const self_type& readable )                                      { Append(readable); return *this; }

  NS_HIDDEN_(void) Insert( char_type c, index_type pos )                                              { Replace(pos, 0, c); }
  NS_HIDDEN_(void) Insert( const char_type* data, index_type pos, size_type length = size_type(-1) )  { Replace(pos, 0, data, length); }
  NS_HIDDEN_(void) Insert( const self_type& readable, index_type pos )                                { Replace(pos, 0, readable); }

  NS_HIDDEN_(void) Cut( index_type cutStart, size_type cutLength )                                    { Replace(cutStart, cutLength, nsnull, 0); }

  NS_HIDDEN_(void) Truncate() { SetLength(0); }

  /**
   * Compare strings of characters. Return 0 if the characters are equal,
   */
  typedef PRInt32 (*ComparatorFunc)(const char_type *a,
                                    const char_type *b,
                                    PRUint32 length);

  static NS_HIDDEN_(PRInt32) DefaultComparator(const char_type *a,
                                               const char_type *b,
                                               PRUint32 length);

  PRBool Equals( const self_type &other,
                 ComparatorFunc c = DefaultComparator ) const;

protected:
  // Prevent people from allocating a nsAString directly.
  ~nsACString() {}
};

/* ------------------------------------------------------------------------- */

/**
 * Below we define nsStringContainer and nsCStringContainer.  These classes
 * have unspecified structure.  In most cases, your code should use
 * nsString/nsCString instead of these classes; if you prefer C-style
 * programming, then look no further.
 */

class nsStringContainer : public nsAString,
                          private nsStringContainer_base
{
};

class nsCStringContainer : public nsACString,
                           private nsStringContainer_base
{
};

/**
 * The following classes are C++ helper classes that make the frozen string
 * API easier to use.
 */

/**
 * Rename symbols to avoid conflicting with internal versions.
 */
#define nsString                       nsString_external
#define nsCString                      nsCString_external
#define nsDependentString              nsDependentString_external
#define nsDependentCString             nsDependentCString_external
#define NS_ConvertASCIItoUTF16         NS_ConvertASCIItoUTF16_external
#define NS_ConvertUTF8toUTF16          NS_ConvertUTF8toUTF16_external
#define NS_ConvertUTF16toUTF8          NS_ConvertUTF16toUTF8_external
#define NS_LossyConvertUTF16toASCII    NS_LossyConvertUTF16toASCII_external
#define nsGetterCopies                 nsGetterCopies_external
#define nsCGetterCopies                nsCGetterCopies_external
#define nsDependentSubstring           nsDependentSubstring_external
#define nsDependentCSubstring          nsDependentCSubstring_external

/**
 * basic strings
 */

class nsString : public nsStringContainer
{
public:
  typedef nsString         self_type;
  typedef nsAString        abstract_string_type;

  nsString()
  {
    NS_StringContainerInit(*this);
  }

  nsString(const self_type& aString)
  {
    NS_StringContainerInit(*this);
    NS_StringCopy(*this, aString);
  }

  explicit
  nsString(const abstract_string_type& aReadable)
  {
    NS_StringContainerInit(*this);
    NS_StringCopy(*this, aReadable);
  }

  explicit
  nsString(const char_type* aData, size_type aLength = PR_UINT32_MAX)
  {
    NS_StringContainerInit2(*this, aData, aLength, 0);
  }
  
  ~nsString()
  {
    NS_StringContainerFinish(*this);
  }

  const char_type* get() const
  {
    return BeginReading();
  }

  self_type& operator=(const self_type& aString)              { Assign(aString);   return *this; }
  self_type& operator=(const abstract_string_type& aReadable) { Assign(aReadable); return *this; }
  self_type& operator=(const char_type* aPtr)                 { Assign(aPtr);      return *this; }
  self_type& operator=(char_type aChar)                       { Assign(aChar);     return *this; }

  void Adopt(const char_type *aData, size_type aLength = PR_UINT32_MAX)
  {
    NS_StringContainerFinish(*this);
    NS_StringContainerInit2(*this, aData, aLength,
                            NS_STRING_CONTAINER_INIT_ADOPT);
  }

protected:
  
  nsString(const char_type* aData, size_type aLength, PRUint32 aFlags)
  {
    NS_StringContainerInit2(*this, aData, aLength, aFlags);
  }
};

class nsCString : public nsCStringContainer
{
public:
  typedef nsCString        self_type;
  typedef nsACString       abstract_string_type;

  nsCString()
  {
    NS_CStringContainerInit(*this);
  }

  nsCString(const self_type& aString)
  {
    NS_CStringContainerInit(*this);
    NS_CStringCopy(*this, aString);
  }

  explicit
  nsCString(const abstract_string_type& aReadable)
  {
    NS_CStringContainerInit(*this);
    NS_CStringCopy(*this, aReadable);
  }

  explicit
  nsCString(const char_type* aData, size_type aLength = PR_UINT32_MAX)
  {
    NS_CStringContainerInit(*this);
    NS_CStringSetData(*this, aData, aLength);
  }
  
  ~nsCString()
  {
    NS_CStringContainerFinish(*this);
  }

  const char_type* get() const
  {
    return BeginReading();
  }
  
  self_type& operator=(const self_type& aString)              { Assign(aString);   return *this; }
  self_type& operator=(const abstract_string_type& aReadable) { Assign(aReadable); return *this; }
  self_type& operator=(const char_type* aPtr)                 { Assign(aPtr);      return *this; }
  self_type& operator=(char_type aChar)                       { Assign(aChar);     return *this; }

  void Adopt(const char_type *aData, size_type aLength = PR_UINT32_MAX)
  {
    NS_CStringContainerFinish(*this);
    NS_CStringContainerInit2(*this, aData, aLength,
                             NS_CSTRING_CONTAINER_INIT_ADOPT);
  }

protected:
  
  nsCString(const char_type* aData, size_type aLength, PRUint32 aFlags)
  {
    NS_CStringContainerInit2(*this, aData, aLength, aFlags);
  }
};


/**
 * dependent strings
 */

class nsDependentString : public nsString
{
public:
  typedef nsDependentString         self_type;

  nsDependentString() {}

  explicit
  nsDependentString(const char_type* aData, size_type aLength = PR_UINT32_MAX)
    : nsString(aData, aLength, NS_CSTRING_CONTAINER_INIT_DEPEND)
  {}

  void Rebind(const char_type* aData, size_type aLength = PR_UINT32_MAX)
  {
    NS_StringContainerFinish(*this);
    NS_StringContainerInit2(*this, aData, aLength,
                            NS_STRING_CONTAINER_INIT_DEPEND);
  }
  
private:
  self_type& operator=(const self_type& aString); // NOT IMPLEMENTED
};

class nsDependentCString : public nsCString
{
public:
  typedef nsDependentCString        self_type;

  nsDependentCString() {}

  explicit
  nsDependentCString(const char_type* aData, size_type aLength = PR_UINT32_MAX)
    : nsCString(aData, aLength, NS_CSTRING_CONTAINER_INIT_DEPEND)
  {}

  void Rebind(const char_type* aData, size_type aLength = PR_UINT32_MAX)
  {
    NS_CStringContainerFinish(*this);
    NS_CStringContainerInit2(*this, aData, aLength,
                             NS_CSTRING_CONTAINER_INIT_DEPEND);
  }
  
private:
  self_type& operator=(const self_type& aString); // NOT IMPLEMENTED
};


/**
 * conversion classes
 */

inline void
CopyUTF16toUTF8(const nsAString& aSource, nsACString& aDest)
{
  NS_UTF16ToCString(aSource, NS_CSTRING_ENCODING_UTF8, aDest);
}

inline void
CopyUTF8toUTF16(const nsACString& aSource, nsAString& aDest)
{
  NS_CStringToUTF16(aSource, NS_CSTRING_ENCODING_UTF8, aDest);
}

inline void
LossyCopyUTF16toASCII(const nsAString& aSource, nsACString& aDest)
{
  NS_UTF16ToCString(aSource, NS_CSTRING_ENCODING_ASCII, aDest);
}

inline void
CopyASCIItoUTF16(const nsACString& aSource, nsAString& aDest)
{
  NS_CStringToUTF16(aSource, NS_CSTRING_ENCODING_ASCII, aDest);
}

NS_COM_GLUE char*
ToNewUTF8String(const nsAString& aSource);

class NS_ConvertASCIItoUTF16 : public nsString
{
public:
  typedef NS_ConvertASCIItoUTF16    self_type;

  explicit
  NS_ConvertASCIItoUTF16(const nsACString& aStr)
  {
    NS_CStringToUTF16(aStr, NS_CSTRING_ENCODING_ASCII, *this);
  }

  explicit
  NS_ConvertASCIItoUTF16(const char* aData, PRUint32 aLength = PR_UINT32_MAX)
  {
    NS_CStringToUTF16(nsDependentCString(aData, aLength),
                      NS_CSTRING_ENCODING_ASCII, *this);
  }

private:
  self_type& operator=(const self_type& aString); // NOT IMPLEMENTED
};

class NS_ConvertUTF8toUTF16 : public nsString
{
public:
  typedef NS_ConvertUTF8toUTF16    self_type;

  explicit
  NS_ConvertUTF8toUTF16(const nsACString& aStr)
  {
    NS_CStringToUTF16(aStr, NS_CSTRING_ENCODING_UTF8, *this);
  }

  explicit
  NS_ConvertUTF8toUTF16(const char* aData, PRUint32 aLength = PR_UINT32_MAX)
  {
    NS_CStringToUTF16(nsDependentCString(aData, aLength),
                      NS_CSTRING_ENCODING_UTF8, *this);
  }

private:
  self_type& operator=(const self_type& aString); // NOT IMPLEMENTED
};

class NS_ConvertUTF16toUTF8 : public nsCString
{
public:
  typedef NS_ConvertUTF16toUTF8    self_type;

  explicit
  NS_ConvertUTF16toUTF8(const nsAString& aStr)
  {
    NS_UTF16ToCString(aStr, NS_CSTRING_ENCODING_UTF8, *this);
  }

  explicit
  NS_ConvertUTF16toUTF8(const PRUnichar* aData, PRUint32 aLength = PR_UINT32_MAX)
  {
    NS_UTF16ToCString(nsDependentString(aData, aLength),
                      NS_CSTRING_ENCODING_UTF8, *this);
  }

private:
  self_type& operator=(const self_type& aString); // NOT IMPLEMENTED
};

class NS_LossyConvertUTF16toASCII : public nsCString
{
public:
  typedef NS_LossyConvertUTF16toASCII    self_type;

  explicit
  NS_LossyConvertUTF16toASCII(const nsAString& aStr)
  {
    NS_UTF16ToCString(aStr, NS_CSTRING_ENCODING_ASCII, *this);
  }

  explicit
  NS_LossyConvertUTF16toASCII(const PRUnichar* aData, PRUint32 aLength = PR_UINT32_MAX)
  {
    NS_UTF16ToCString(nsDependentString(aData, aLength),
                      NS_CSTRING_ENCODING_ASCII, *this);
  }

private:
  self_type& operator=(const self_type& aString); // NOT IMPLEMENTED
};


/**
 * literal strings
 *
 * NOTE: HAVE_CPP_2BYTE_WCHAR_T may be automatically defined for some platforms
 * in nscore.h.  On other platforms, it may be defined in xpcom-config.h.
 * Under GCC, this define should only be set if compiling with -fshort-wchar.
 */

#ifdef HAVE_CPP_2BYTE_WCHAR_T
  #define NS_LL(s)                                L##s
  #define NS_MULTILINE_LITERAL_STRING(s)          nsDependentString(NS_REINTERPRET_CAST(const nsAString::char_type*, s), PRUint32((sizeof(s)/sizeof(wchar_t))-1))
  #define NS_MULTILINE_LITERAL_STRING_INIT(n,s)   n(NS_REINTERPRET_CAST(const nsAString::char_type*, s), PRUint32((sizeof(s)/sizeof(wchar_t))-1))
  #define NS_NAMED_MULTILINE_LITERAL_STRING(n,s)  const nsDependentString n(NS_REINTERPRET_CAST(const nsAString::char_type*, s), PRUint32((sizeof(s)/sizeof(wchar_t))-1))
  typedef nsDependentString nsLiteralString;
#else
  #define NS_LL(s)                                s
  #define NS_MULTILINE_LITERAL_STRING(s)          NS_ConvertASCIItoUTF16(s, PRUint32(sizeof(s)-1))
  #define NS_MULTILINE_LITERAL_STRING_INIT(n,s)   n(s, PRUint32(sizeof(s)-1))
  #define NS_NAMED_MULTILINE_LITERAL_STRING(n,s)  const NS_ConvertASCIItoUTF16 n(s, PRUint32(sizeof(s)-1))
  typedef NS_ConvertASCIItoUTF16 nsLiteralString;
#endif

/*
 * Macro arguments used in concatenation or stringification won't be expanded.
 * Therefore, in order for |NS_L(FOO)| to work as expected (which is to expand
 * |FOO| before doing whatever |NS_L| needs to do to it) a helper macro needs
 * to be inserted in between to allow the macro argument to expand.
 * See "3.10.6 Separate Expansion of Macro Arguments" of the CPP manual for a
 * more accurate and precise explanation.
 */

#define NS_L(s)                                   NS_LL(s)

#define NS_LITERAL_STRING(s)                      NS_STATIC_CAST(const nsString&, NS_MULTILINE_LITERAL_STRING(NS_LL(s)))
#define NS_LITERAL_STRING_INIT(n,s)               NS_MULTILINE_LITERAL_STRING_INIT(n, NS_LL(s))
#define NS_NAMED_LITERAL_STRING(n,s)              NS_NAMED_MULTILINE_LITERAL_STRING(n, NS_LL(s))

#define NS_LITERAL_CSTRING(s)                     NS_STATIC_CAST(const nsDependentCString&, nsDependentCString(s, PRUint32(sizeof(s)-1)))
#define NS_LITERAL_CSTRING_INIT(n,s)              n(s, PRUint32(sizeof(s)-1))
#define NS_NAMED_LITERAL_CSTRING(n,s)             const nsDependentCString n(s, PRUint32(sizeof(s)-1))

typedef nsDependentCString nsLiteralCString;


/**
 * getter_Copies support
 *
 *    NS_IMETHOD GetBlah(PRUnichar**);
 *
 *    void some_function()
 *    {
 *      nsString blah;
 *      GetBlah(getter_Copies(blah));
 *      // ...
 *    }
 */

class nsGetterCopies
{
public:
  typedef PRUnichar char_type;

  nsGetterCopies(nsString& aStr)
    : mString(aStr), mData(nsnull)
  {}

  ~nsGetterCopies()
  {
    mString.Adopt(mData);
  }

  operator char_type**()
  {
    return &mData;
  }

private:
  nsString&  mString;
  char_type* mData;
};

inline nsGetterCopies
getter_Copies(nsString& aString)
{
  return nsGetterCopies(aString);
}

class nsCGetterCopies
{
public:
  typedef char char_type;

  nsCGetterCopies(nsCString& aStr)
    : mString(aStr), mData(nsnull)
  {}

  ~nsCGetterCopies()
  {
    mString.Adopt(mData);
  }

  operator char_type**()
  {
    return &mData;
  }

private:
  nsCString& mString;
  char_type* mData;
};

inline nsCGetterCopies
getter_Copies(nsCString& aString)
{
  return nsCGetterCopies(aString);
}


/**
* substrings
*/

class nsDependentSubstring : public nsStringContainer
{
public:
  typedef nsDependentSubstring self_type;
  typedef nsAString            abstract_string_type;

  ~nsDependentSubstring()
  {
    NS_StringContainerFinish(*this);
  }

  nsDependentSubstring()
  {
    NS_StringContainerInit(*this);
  }

  nsDependentSubstring(const char_type *aStart, PRUint32 aLength)
  {
    NS_StringContainerInit2(*this, aStart, aLength,
                            NS_STRING_CONTAINER_INIT_DEPEND |
                            NS_STRING_CONTAINER_INIT_SUBSTRING);
  }

  nsDependentSubstring(const abstract_string_type& aStr,
                       PRUint32 aStartPos)
  {
    const PRUnichar* data;
    PRUint32 len = NS_StringGetData(aStr, &data);

    if (aStartPos > len)
      aStartPos = len;

    NS_StringContainerInit2(*this, data + aStartPos, len - aStartPos,
                            NS_STRING_CONTAINER_INIT_DEPEND |
                            NS_STRING_CONTAINER_INIT_SUBSTRING);
  }

  nsDependentSubstring(const abstract_string_type& aStr,
                       PRUint32 aStartPos, PRUint32 aLength)
  {
    const PRUnichar* data;
    PRUint32 len = NS_StringGetData(aStr, &data);

    if (aStartPos > len)
      aStartPos = len;

    if (aStartPos + aLength > len)
      aLength = len - aStartPos;

    NS_StringContainerInit2(*this, data + aStartPos, aLength,
                            NS_STRING_CONTAINER_INIT_DEPEND |
                            NS_STRING_CONTAINER_INIT_SUBSTRING);
  }

  void Rebind(const char_type *aStart, PRUint32 aLength)
  {
    NS_StringContainerFinish(*this);
    NS_StringContainerInit2(*this, aStart, aLength,
                            NS_STRING_CONTAINER_INIT_DEPEND |
                            NS_STRING_CONTAINER_INIT_SUBSTRING);
  }

private:
  self_type& operator=(const self_type& aString); // NOT IMPLEMENTED
};

class nsDependentCSubstring : public nsCStringContainer
{
public:
  typedef nsDependentCSubstring self_type;
  typedef nsACString            abstract_string_type;

  ~nsDependentCSubstring()
  {
    NS_CStringContainerFinish(*this);
  }

  nsDependentCSubstring()
  {
    NS_CStringContainerInit(*this);
  }

  nsDependentCSubstring(const char_type *aStart, PRUint32 aLength)
  {
    NS_CStringContainerInit2(*this, aStart, aLength,
                             NS_CSTRING_CONTAINER_INIT_DEPEND |
                             NS_CSTRING_CONTAINER_INIT_SUBSTRING);
  }

  nsDependentCSubstring(const abstract_string_type& aStr,
                        PRUint32 aStartPos)
  {
    const char* data;
    PRUint32 len = NS_CStringGetData(aStr, &data);

    if (aStartPos > len)
      aStartPos = len;

    NS_CStringContainerInit2(*this, data + aStartPos, len - aStartPos,
                             NS_CSTRING_CONTAINER_INIT_DEPEND |
                             NS_CSTRING_CONTAINER_INIT_SUBSTRING);
  }

  nsDependentCSubstring(const abstract_string_type& aStr,
                        PRUint32 aStartPos, PRUint32 aLength)
  {
    const char* data;
    PRUint32 len = NS_CStringGetData(aStr, &data);

    if (aStartPos > len)
      aStartPos = len;

    if (aStartPos + aLength > len)
      aLength = len - aStartPos;

    NS_CStringContainerInit2(*this, data + aStartPos, aLength,
                             NS_CSTRING_CONTAINER_INIT_DEPEND |
                             NS_CSTRING_CONTAINER_INIT_SUBSTRING);
  }

  void Rebind(const char_type *aStart, PRUint32 aLength)
  {
    NS_CStringContainerFinish(*this);
    NS_CStringContainerInit2(*this, aStart, aLength,
                             NS_CSTRING_CONTAINER_INIT_DEPEND |
                             NS_CSTRING_CONTAINER_INIT_SUBSTRING);
  }

private:
  self_type& operator=(const self_type& aString); // NOT IMPLEMENTED
};


/**
 * Various nsDependentC?Substring constructor functions
 */

// PRUnichar
inline const nsDependentSubstring
Substring( const nsAString& str, PRUint32 startPos )
{
  return nsDependentSubstring(str, startPos);
}

inline const nsDependentSubstring
Substring( const nsAString& str, PRUint32 startPos, PRUint32 length )
{
  return nsDependentSubstring(str, startPos, length);
}

inline const nsDependentSubstring
Substring( const PRUnichar* start, const PRUnichar* end )
{
  return nsDependentSubstring(start, end - start);
}

inline const nsDependentSubstring
Substring( const PRUnichar* start, PRUint32 length )
{
  return nsDependentSubstring(start, length);
}

inline const nsDependentSubstring
StringHead( const nsAString& str, PRUint32 count )
{
  return nsDependentSubstring(str, 0, count);
}

inline const nsDependentSubstring
StringTail( const nsAString& str, PRUint32 count )
{
  return nsDependentSubstring(str, str.Length() - count, count);
}

// char
inline const nsDependentCSubstring
Substring( const nsACString& str, PRUint32 startPos )
{
  return nsDependentCSubstring(str, startPos);
}

inline const nsDependentCSubstring
Substring( const nsACString& str, PRUint32 startPos, PRUint32 length )
{
  return nsDependentCSubstring(str, startPos, length);
}

inline
const nsDependentCSubstring
Substring( const char* start, const char* end )
{
  return nsDependentCSubstring(start, end - start);
}

inline
const nsDependentCSubstring
Substring( const char* start, PRUint32 length )
{
  return nsDependentCSubstring(start, length);
}

inline const nsDependentCSubstring
StringHead( const nsACString& str, PRUint32 count )
{
  return nsDependentCSubstring(str, 0, count);
}

inline const nsDependentCSubstring
StringTail( const nsACString& str, PRUint32 count )
{
  return nsDependentCSubstring(str, str.Length() - count, count);
}

#define EmptyCString() nsCString()
#define EmptyString() nsString()

/**
 * The following declarations are *deprecated*, and are included here only
 * to make porting from existing code that doesn't use the frozen string API
 * easier. They may disappear in the future.
 */

inline char*
ToNewCString(const nsACString& aStr)
{
  return NS_CStringCloneData(aStr);
}

inline PRUnichar*
ToNewUnicode(const nsAString& aStr)
{
  return NS_StringCloneData(aStr);
}

typedef nsString PromiseFlatString;
typedef nsCString PromiseFlatCString;

typedef nsCString nsCAutoString;
typedef nsString nsAutoString;

#endif // nsStringAPI_h__