win: Add memory map range intersection helper

util/numeric/checked_range.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 86 matching lines @@
   //!
   //! This method must only be called if IsValid() would return `true` for both
   //! CheckedRange objects involved.
   bool ContainsRange(const CheckedRange<ValueType, SizeType>& that) const {
     DCHECK(IsValid());
     DCHECK(that.IsValid());
 
     return that.base() >= base() && that.end() <= end();
   }
 
+  //! \brief Returns whether the range overlaps another range.
+  //!
+  //! \param[in] that The (possibly) overlapping range.
+  //!
+  //! \return `true` if `this` range, the first range, overlaps \a that,
+  //!     the provided range. `false` otherwise.
+  //!
+  //! Ranges are considered to be closed-open [base, end) for this test. Zero
+  //! length ranges are never considered to overlap another range.
+  //!
+  //! This method must only be called if IsValid() would return `true` for both
+  //! CheckedRange objects involved.
+  bool OverlapsRange(const CheckedRange<ValueType, SizeType>& that) const {
+    DCHECK(IsValid());
+    DCHECK(that.IsValid());
+
+    if (size() == 0 || that.size() == 0)
+      return false;
+
+    return base() < that.end() && that.base() < end();
+  }
+
  private:
   ValueType base_;
   SizeType size_;
-
-  DISALLOW_COPY_AND_ASSIGN(CheckedRange);
 };
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_NUMERIC_CHECKED_RANGE_H_