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diff --git a/o3d/compiler/puritan/puritan_shared_ptr.h b/o3d/compiler/puritan/puritan_shared_ptr.h
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+/*
+ * Copyright 2009, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+//
+// A simple reference counted pointer implementation. It is a subset
+// of the boost/tr1 shared_ptr class, which is expected to be part of
+// the next C++ standard.  See section 20.6.6 [util.smartptr] of the
+// draft standard for a full description of the standard interface.
+//
+// The following standard features have been omitted from this implementation:
+//   - no custom deallocators - uses delete
+//   - no support for enable_shared_from_this
+//   - no support for smart pointer casts
+//   - no support for features that rely on variadic templates
+//   - not exception-safe
+//   - no overloaded comparison operators (e.g. operator<). They're
+//     convenient, but they can be explicitly defined outside the class.
+//
+
+#ifndef UTIL_GTL_PURITAN_SHARED_PTR_H__
+#define UTIL_GTL_PURITAN_SHARED_PTR_H__
+
+#include <algorithm>  // for swap
+
+template <typename T> class shared_ptr;
+template <typename T> class weak_ptr;
+
+// This class is an internal implementation detail for shared_ptr.
+//
+class SharedPtrControlBlock {
+  template <typename T> friend class shared_ptr;
+  template <typename T> friend class weak_ptr;
+ private:
+  SharedPtrControlBlock() : refcount_(1), weak_count_(1) { }
+  int refcount_;
+  int weak_count_;
+};
+
+template <typename T>
+class shared_ptr {
+  template <typename U> friend class weak_ptr;
+ public:
+  typedef T element_type;
+
+  explicit shared_ptr(T* ptr = NULL)
+      : ptr_(ptr),
+        control_block_(ptr != NULL ? new SharedPtrControlBlock : NULL) {
+  }
+
+  // Copy constructor: makes this object a copy of ptr
+  template <typename U>
+  shared_ptr(const shared_ptr<U>& ptr)
+      : ptr_(NULL),
+        control_block_(NULL) {
+    Initialize(ptr);
+  }
+  // Need non-templated version to prevent the compiler-generated default
+  shared_ptr(const shared_ptr<T>& ptr)
+      : ptr_(NULL),
+        control_block_(NULL) {
+    Initialize(ptr);
+  }
+
+  // Assignment operator. Replaces the existing shared_ptr with ptr.
+  template <typename U>
+  shared_ptr<T>& operator=(const shared_ptr<U>& ptr) {
+    if (ptr_ != ptr.ptr_) {
+      shared_ptr<T> me(ptr);   // will hold our previous state to be destroyed.
+      swap(me);
+    }
+    return *this;
+  }
+
+  // Need non-templated version to prevent the compiler-generated default
+  shared_ptr<T>& operator=(const shared_ptr<T>& ptr) {
+    if (ptr_ != ptr.ptr_) {
+      shared_ptr<T> me(ptr);   // will hold our previous state to be destroyed.
+      swap(me);
+    }
+    return *this;
+  }
+
+  ~shared_ptr() {
+    if (ptr_ != NULL) {
+      if (--control_block_->refcount_ == 0) {
+        delete ptr_;
+
+        // weak_count_ is defined as the number of weak_ptrs that observe
+        // ptr_, plus 1 if refcount_ is nonzero.
+        if (--control_block_->weak_count_ == 0) {
+          delete control_block_;
+        }
+      }
+    }
+  }
+
+  // Replaces underlying raw pointer with the one passed in.  The reference
+  // count is set to one (or zero if the pointer is NULL) for the pointer
+  // being passed in and decremented for the one being replaced.
+  void reset(T* p = NULL) {
+    if (p != ptr_) {
+      shared_ptr<T> tmp(p);
+      tmp.swap(*this);
+    }
+  }
+
+  // Exchanges the contents of this with the contents of r.  This function
+  // supports more efficient swapping since it eliminates the need for a
+  // temporary shared_ptr object.
+  void swap(shared_ptr<T>& r) {
+    std::swap(ptr_, r.ptr_);
+    std::swap(control_block_, r.control_block_);
+  }
+
+  // The following function is useful for gaining access to the underlying
+  // pointer when a shared_ptr remains in scope so the reference-count is
+  // known to be > 0 (e.g. for parameter passing).
+  T* get() const {
+    return ptr_;
+  }
+
+  T& operator*() const {
+    return *ptr_;
+  }
+
+  T* operator->() const {
+    return ptr_;
+  }
+
+  long use_count() const {
+    return control_block_ ? control_block_->refcount_ : 1;
+  }
+
+  bool unique() const {
+    return use_count() == 1;
+  }
+
+ private:
+  // If r is non-empty, initialize *this to share ownership with r,
+  // increasing the underlying reference count.
+  // If r is empty, *this remains empty.
+  // Requires: this is empty, namely this->ptr_ == NULL.
+  template <typename U>
+  void Initialize(const shared_ptr<U>& r) {
+    if (r.control_block_ != NULL) {
+      ++r.control_block_->refcount_;
+
+      ptr_ = r.ptr_;
+      control_block_ = r.control_block_;
+    }
+  }
+
+  T* ptr_;
+  SharedPtrControlBlock* control_block_;
+
+  template <typename U>
+  friend class shared_ptr;
+};
+
+// Matches the interface of std::swap as an aid to generic programming.
+template <typename T> void swap(shared_ptr<T>& r, shared_ptr<T>& s) {
+  r.swap(s);
+}
+
+// See comments at the top of the file for a description of why this
+// class exists, and the draft C++ standard (as of October 2007 the
+// latest draft is N2461) for the detailed specification.
+template <typename T>
+class weak_ptr {
+  template <typename U> friend class weak_ptr;
+ public:
+  typedef T element_type;
+
+  // Create an empty (i.e. already expired) weak_ptr.
+  weak_ptr() : ptr_(NULL), control_block_(NULL) { }
+
+  // Create a weak_ptr that observes the same object that ptr points
+  // to.  Note that there is no race condition here: we know that the
+  // control block can't disappear while we're looking at it because
+  // it is owned by at least one shared_ptr, ptr.
+  template <typename U> weak_ptr(const shared_ptr<U>& ptr) {
+    CopyFrom(ptr.ptr_, ptr.control_block_);
+  }
+
+  // Copy a weak_ptr. The object it points to might disappear, but we
+  // don't care: we're only working with the control block, and it can't
+  // disappear while we're looking at because it's owned by at least one
+  // weak_ptr, ptr.
+  template <typename U> weak_ptr(const weak_ptr<U>& ptr) {
+    CopyFrom(ptr.ptr_, ptr.control_block_);
+  }
+
+  // Need non-templated version to prevent default copy constructor
+  weak_ptr(const weak_ptr& ptr) {
+    CopyFrom(ptr.ptr_, ptr.control_block_);
+  }
+
+  // Destroy the weak_ptr. If no shared_ptr owns the control block, and if
+  // we are the last weak_ptr to own it, then it can be deleted. Note that
+  // weak_count_ is defined as the number of weak_ptrs sharing this control
+  // block, plus 1 if there are any shared_ptrs. We therefore know that it's
+  // safe to delete the control block when weak_count_ reaches 0, without
+  // having to perform any additional tests.
+  ~weak_ptr() {
+    if (control_block_ != NULL &&
+        (--control_block_->weak_count_) == 0) {
+      delete control_block_;
+    }
+  }
+
+  weak_ptr& operator=(const weak_ptr& ptr) {
+    if (&ptr != this) {
+      weak_ptr tmp(ptr);
+      tmp.swap(*this);
+    }
+    return *this;
+  }
+  template <typename U> weak_ptr& operator=(const weak_ptr<U>& ptr) {
+    weak_ptr tmp(ptr);
+    tmp.swap(*this);
+    return *this;
+  }
+  template <typename U> weak_ptr& operator=(const shared_ptr<U>& ptr) {
+    weak_ptr tmp(ptr);
+    tmp.swap(*this);
+    return *this;
+  }
+
+  void swap(weak_ptr& ptr) {
+    ::swap(ptr_, ptr.ptr_);
+    ::swap(control_block_, ptr.control_block_);
+  }
+
+  void reset() {
+    weak_ptr tmp;
+    tmp.swap(*this);
+  }
+
+  // Return the number of shared_ptrs that own the object we are observing.
+  // Note that this number can be 0 (if this pointer has expired).
+  long use_count() const {
+    return control_block_ != NULL ? control_block_->refcount_ : 0;
+  }
+
+  bool expired() const { return use_count() == 0; }
+
+ private:
+  void CopyFrom(T* ptr, SharedPtrControlBlock* control_block) {
+    ptr_ = ptr;
+    control_block_ = control_block;
+    if (control_block_ != NULL)
+      ++control_block_->weak_count_;
+  }
+
+ private:
+  element_type* ptr_;
+  SharedPtrControlBlock* control_block_;
+};
+
+template <typename T> void swap(weak_ptr<T>& r, weak_ptr<T>& s) {
+  r.swap(s);
+}
+
+#endif  // UTIL_GTL_PURITAN_SHARED_PTR_H__