xpcom/string/nsTSubstringTuple.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6 // IWYU pragma: private, include "nsString.h"
   7
   8 /**
   9  * nsTSubstringTuple_CharT
  10  *
  11  * Represents a tuple of string fragments.  Built as a recursive binary tree.
  12  * It is used to implement the concatenation of two or more string objects.
  13  *
  14  * NOTE: This class is a private implementation detail and should never be
  15  * referenced outside the string code.
  16  */
  17 class nsTSubstringTuple_CharT
  18 {
  19 public:
  20
  21   typedef CharT                      char_type;
  22   typedef nsCharTraits<char_type>    char_traits;
  23
  24   typedef nsTSubstringTuple_CharT    self_type;
  25   typedef nsTSubstring_CharT         substring_type;
  26   typedef nsTSubstring_CharT         base_string_type;
  27   typedef uint32_t                   size_type;
  28
  29 public:
  30
  31   nsTSubstringTuple_CharT(const base_string_type* aStrA,
  32                           const base_string_type* aStrB)
  33     : mHead(nullptr)
  34     , mFragA(aStrA)
  35     , mFragB(aStrB)
  36   {
  37   }
  38
  39   nsTSubstringTuple_CharT(const self_type& aHead,
  40                           const base_string_type* aStrB)
  41     : mHead(&aHead)
  42     , mFragA(nullptr) // this fragment is ignored when aHead != nullptr
  43     , mFragB(aStrB)
  44   {
  45   }
  46
  47   /**
  48    * computes the aggregate string length
  49    */
  50   size_type Length() const;
  51
  52   /**
  53    * writes the aggregate string to the given buffer.  bufLen is assumed
  54    * to be equal to or greater than the value returned by the Length()
  55    * method.  the string written to |buf| is not null-terminated.
  56    */
  57   void WriteTo(char_type* aBuf, uint32_t aBufLen) const;
  58
  59   /**
  60    * returns true if this tuple is dependent on (i.e., overlapping with)
  61    * the given char sequence.
  62    */
  63   bool IsDependentOn(const char_type* aStart, const char_type* aEnd) const;
  64
  65 private:
  66
  67   const self_type*        mHead;
  68   const base_string_type* mFragA;
  69   const base_string_type* mFragB;
  70 };
  71
  72 inline const nsTSubstringTuple_CharT
  73 operator+(const nsTSubstringTuple_CharT::base_string_type& aStrA,
  74           const nsTSubstringTuple_CharT::base_string_type& aStrB)
  75 {
  76   return nsTSubstringTuple_CharT(&aStrA, &aStrB);
  77 }
  78
  79 inline const nsTSubstringTuple_CharT
  80 operator+(const nsTSubstringTuple_CharT& aHead,
  81           const nsTSubstringTuple_CharT::base_string_type& aStrB)
  82 {
  83   return nsTSubstringTuple_CharT(aHead, &aStrB);
  84 }