Initial commit

Handle.cpp

@@ -0,0 +1,58 @@
+//------------------------------- Handle.h -------------------------------------
+// 
+// This software is in the public domain.  The only restriction on its use is
+// that no one can remove it from the public domain by claiming ownership of it,
+// including the original authors.
+// 
+// There is no warranty of correctness on the software contained herein.  Use
+// at your own risk.
+// 
+//------------------------------------------------------------------------------
+
+#include "hash_append.h"
+#include "Handle.h"
+#include <unordered_set>
+
+// namespace acme is used to demonstrate example code.  It is not proposed.
+
+namespace acme
+{
+
+class Handle::CheshireCat
+{
+    std::unordered_set<int> data_;
+public:
+    CheshireCat(int data1, int data2)
+    {
+        data_.insert(data1);
+        data_.insert(data2);
+    }
+
+    friend
+    void
+    hash_append(Handle::type_erased_hasher& h, CheshireCat const& c);
+};
+
+void
+hash_append(Handle::type_erased_hasher& h, Handle::CheshireCat const& c)
+{
+    using xstd::hash_append;
+    hash_append(h, c.data_);
+}
+
+Handle::Handle()
+    : smile(new CheshireCat(1, 2))
+{
+}
+
+Handle::Handle(int data1, int data2)
+    : smile(new CheshireCat(data1, data2))
+{
+}
+
+Handle::~Handle()
+{
+    delete smile;
+}
+
+}  // acme

Handle.h

@@ -0,0 +1,61 @@
+//------------------------------- Handle.h -------------------------------------
+// 
+// This software is in the public domain.  The only restriction on its use is
+// that no one can remove it from the public domain by claiming ownership of it,
+// including the original authors.
+// 
+// There is no warranty of correctness on the software contained herein.  Use
+// at your own risk.
+// 
+//------------------------------------------------------------------------------
+
+#ifndef HANDLE_H
+#define HANDLE_H
+
+#include "hash_adaptors.h"
+
+// namespace acme is used to demonstrate example code.  It is not proposed.
+
+namespace acme
+{
+
+class Handle
+{
+    struct CheshireCat;               // Not defined here
+    CheshireCat* smile;               // Handle
+
+public:
+    Handle();                         // Default Constructor
+    ~Handle();                        // Destructor
+    Handle(Handle const&) = delete;
+    Handle& operator=(Handle const&) = delete;
+    Handle(int data1, int data2);
+    // Other operations...
+
+    // Hash support
+    using type_erased_hasher = acme::type_erased_hasher<std::size_t>;
+
+    friend
+    void
+    hash_append(type_erased_hasher&, CheshireCat const&);
+
+    template <class Hasher>
+    friend
+    void
+    hash_append(Hasher& h, Handle const& x)
+    {
+        using xstd::hash_append;
+        if (x.smile == nullptr)
+            hash_append(h, nullptr);
+        else
+        {
+            type_erased_hasher temp(std::move(h));
+            hash_append(temp, *x.smile);
+            h = std::move(*temp.target<Hasher>());
+        }
+    }
+};
+
+}  // acme
+
+#endif  // HANDLE_H

README.txt

@@ -0,0 +1,18 @@
+This is a collection of software used to provide an example
+implementation of the proposal currently at:
+
+http://htmlpreview.github.io/?https://github.com/HowardHinnant/papers/blob/master/hashing.html
+
+And to demonstrate example software surrounding / using this proposal.
+
+Though there are a lot of files here, only one file contains an implementation
+of proposed software:
+
+    hash_append.h
+
+Everything in namespace xstd, except for those things in xstd::detail, is
+proposed.  Nothing else is.  The only file containing anything in namespace
+xstd is hash_append.h.
+
+Currently hash_append.h is missing hash_append overloads for many std::containers
+and other objects.  They should be added.