1 files changed, 84 insertions, 0 deletions
diff --git a/xpcom/string/nsTSubstringTuple.h b/xpcom/string/nsTSubstringTuple.h
new file mode 100644
index 000000000..5d24e2159
--- /dev/null
+++ b/xpcom/string/nsTSubstringTuple.h
@@ -0,0 +1,84 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+// IWYU pragma: private, include "nsString.h"
+
+/**
+ * nsTSubstringTuple_CharT
+ *
+ * Represents a tuple of string fragments.  Built as a recursive binary tree.
+ * It is used to implement the concatenation of two or more string objects.
+ *
+ * NOTE: This class is a private implementation detail and should never be
+ * referenced outside the string code.
+ */
+class nsTSubstringTuple_CharT
+{
+public:
+
+  typedef CharT                      char_type;
+  typedef nsCharTraits<char_type>    char_traits;
+
+  typedef nsTSubstringTuple_CharT    self_type;
+  typedef nsTSubstring_CharT         substring_type;
+  typedef nsTSubstring_CharT         base_string_type;
+  typedef uint32_t                   size_type;
+
+public:
+
+  nsTSubstringTuple_CharT(const base_string_type* aStrA,
+                          const base_string_type* aStrB)
+    : mHead(nullptr)
+    , mFragA(aStrA)
+    , mFragB(aStrB)
+  {
+  }
+
+  nsTSubstringTuple_CharT(const self_type& aHead,
+                          const base_string_type* aStrB)
+    : mHead(&aHead)
+    , mFragA(nullptr) // this fragment is ignored when aHead != nullptr
+    , mFragB(aStrB)
+  {
+  }
+
+  /**
+   * computes the aggregate string length
+   */
+  size_type Length() const;
+
+  /**
+   * writes the aggregate string to the given buffer.  bufLen is assumed
+   * to be equal to or greater than the value returned by the Length()
+   * method.  the string written to |buf| is not null-terminated.
+   */
+  void WriteTo(char_type* aBuf, uint32_t aBufLen) const;
+
+  /**
+   * returns true if this tuple is dependent on (i.e., overlapping with)
+   * the given char sequence.
+   */
+  bool IsDependentOn(const char_type* aStart, const char_type* aEnd) const;
+
+private:
+
+  const self_type*        mHead;
+  const base_string_type* mFragA;
+  const base_string_type* mFragB;
+};
+
+inline const nsTSubstringTuple_CharT
+operator+(const nsTSubstringTuple_CharT::base_string_type& aStrA,
+          const nsTSubstringTuple_CharT::base_string_type& aStrB)
+{
+  return nsTSubstringTuple_CharT(&aStrA, &aStrB);
+}
+
+inline const nsTSubstringTuple_CharT
+operator+(const nsTSubstringTuple_CharT& aHead,
+          const nsTSubstringTuple_CharT::base_string_type& aStrB)
+{
+  return nsTSubstringTuple_CharT(aHead, &aStrB);
+}