Support pilfer construction

include/boost/json/array.hpp

@@ -13,6 +13,7 @@
 #include <boost/json/detail/config.hpp>
 #include <boost/json/allocator.hpp>
 #include <boost/json/storage.hpp>
+#include <boost/pilfer.hpp>
 #include <cstdlib>
 #include <initializer_list>
 #include <iterator>
@@ -105,6 +106,9 @@ public:
     BOOST_JSON_DECL
     array(array&& other) noexcept;
 
+    BOOST_JSON_DECL
+    array(pilfered<array> other) noexcept;
+
     BOOST_JSON_DECL
     array(
         array&& other,

include/boost/json/impl/array.ipp

@@ -13,6 +13,7 @@
 #include <boost/json/array.hpp>
 #include <boost/core/exchange.hpp>
 #include <boost/assert.hpp>
+#include <boost/pilfer.hpp>
 #include <algorithm>
 #include <cstdlib>
 #include <limits>
@@ -220,6 +221,14 @@ array(array&& other) noexcept
 {
 }
 
+array::
+array(pilfered<array> other) noexcept
+    : tab_(boost::exchange(
+        other.get().tab_, nullptr))
+    , sp_(other.get().sp_)
+{
+}
+
 array::
 array(
     array&& other,
@@ -497,10 +506,12 @@ reserve(size_type new_capacity)
     }
 
     for(size_type i = 0; i < tab_->size; ++i)
-        ::new(&tab->begin()[i]) value_type(
-            std::move(tab_->begin()[i]));
+        relocate(
+            &tab->begin()[i],
+            tab_->begin()[i]);
     tab->size = tab_->size;
     std::swap(tab, tab_);
+    tab->size = 0; // VFALCO Hack
     table::destroy(tab, sp_);
 }
 

include/boost/json/impl/object.ipp

@@ -327,6 +327,14 @@ object(object&& other) noexcept
 {
 }
 
+object::
+object(pilfered<object> other) noexcept
+    : sp_(std::move(other.get().sp_))
+    , tab_(boost::exchange(
+        other.get().tab_, nullptr))
+{
+}
+
 object::
 object(
     object&& other,

include/boost/json/impl/value.ipp

@@ -82,6 +82,48 @@ value(value&& other) noexcept
     other.kind_ = json::kind::null;
 }
 
+value::
+value(pilfered<value> p) noexcept
+{
+    auto& other = p.get();
+    switch(other.kind_)
+    {
+    case json::kind::object:
+        ::new(&obj_) object(
+            pilfer(other.obj_));
+        break;
+
+    case json::kind::array:
+        ::new(&arr_) array(
+            std::move(other.arr_));
+        break;
+
+    case json::kind::string:
+        ::new(&str_) string(
+            std::move(other.str_));
+        break;
+
+    case json::kind::number:
+        ::new(&nat_.sp_) storage_ptr(
+            std::move(other.nat_.sp_));
+        ::new(&nat_.num_) number(
+            std::move(other.nat_.num_));
+        break;
+
+    case json::kind::boolean:
+        ::new(&nat_.sp_) storage_ptr(
+            std::move(other.nat_.sp_));
+        nat_.bool_ = other.nat_.bool_;
+        break;
+
+    case json::kind::null:
+        ::new(&nat_.sp_) storage_ptr(
+            std::move(other.nat_.sp_));
+        break;
+    }
+    kind_ = other.kind_;
+}
+
 value::
 value(
     value&& other,

include/boost/json/object.hpp

@@ -13,6 +13,7 @@
 #include <boost/json/detail/config.hpp>
 #include <boost/json/storage.hpp>
 #include <boost/utility/string_view.hpp>
+#include <boost/pilfer.hpp>
 #include <cstdlib>
 #include <initializer_list>
 #include <iterator>
@@ -139,6 +140,9 @@ public:
     BOOST_JSON_DECL
     object(object&& other) noexcept;
 
+    BOOST_JSON_DECL
+    object(pilfered<object> other) noexcept;
+
     BOOST_JSON_DECL
     object(
         object&& other,

include/boost/json/value.hpp

@@ -21,6 +21,7 @@
 #include <boost/json/detail/value.hpp>
 #include <boost/type_traits/make_void.hpp>
 #include <boost/utility/string_view.hpp>
+#include <boost/pilfer.hpp>
 #include <cstdlib>
 #include <initializer_list>
 #include <iosfwd>
@@ -133,6 +134,10 @@ public:
     BOOST_JSON_DECL
     value(value&& other) noexcept;
 
+    /// Pilfer constructor
+    BOOST_JSON_DECL
+    value(pilfered<value> other) noexcept;
+
     /// Move construct a value, using the specified storage
     BOOST_JSON_DECL
     value(