Merge branch 'json-view/16-view-simd' into json-view/19-edit-set

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/view/lookup.hpp

@@ -84,9 +84,10 @@ class short_key
     std::uint64_t m_b = 0;
 };
 
-/// the key node of the last member of an object with the given key, or
-/// nullptr (the last one, as materialize() and parse() keep it); most keys are
-/// rejected by their length, from the index alone
+/// the key node of the first member of an object with the given key, or
+/// nullptr (the search stops at the first match; materialize() and parse()
+/// keep the last value of a duplicate key instead); most keys are rejected by
+/// their length, from the index alone
 template<bool Editable>
 const node* find_member(const document_data& d, const node* object, const char* key, std::size_t n) noexcept
 {
@@ -97,7 +98,6 @@ const node* find_member(const document_data& d, const node* object, const char*
     }
     const node* const end = nav::end(d, object);
     const auto* const k = reinterpret_cast<const unsigned char*>(key); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
-    const node* last = nullptr;
     if (NLOHMANN_VIEW_LIKELY(n <= 16))
     {
         const short_key probe(k, n);
@@ -105,19 +105,19 @@ const node* find_member(const document_data& d, const node* object, const char*
         {
             if (m->len == n && probe.matches(reinterpret_cast<const unsigned char*>(d.str(*m)))) // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
             {
-                last = m;
+                return m;
             }
         }
-        return last;
+        return nullptr;
     }
     for (const node* m = nav::first(d, object); m != end; m = document_data::after(m + 1))
     {
         if (m->len == n && std::memcmp(d.str(*m), key, n) == 0)
         {
-            last = m;
+            return m;
         }
     }
-    return last;
+    return nullptr;
 }
 
 /// whether an integer type is accepted as an array index by the view's

include/nlohmann/detail/view/object_index.hpp

@@ -22,8 +22,8 @@
 // large objects). An object with document_data::index_min_members members or
 // more gets an open-addressing table after parsing; its node stores the
 // number of the table (1-based) in `extra`. A slot holds the offset of a key
-// node from its object node (0: empty). Of duplicate keys, the last is kept,
-// as for the linear search, and as basic_json::parse() does.
+// node from its object node (0: empty). Of duplicate keys, the first is kept,
+// as for the linear search.
 //
 // The hash is not seeded, so keys chosen to collide could make the build
 // quadratic. A key therefore sits at most index_max_displacement slots away
@@ -92,8 +92,7 @@ inline void build_object_index(document_data& d, node* obj)
             const node* const other = obj + slots[i];
             if (other->len == k->len && (k->len == 0 || std::memcmp(d.str(*other), key, k->len) == 0))
             {
-                duplicate = true; // keep the last: the key's slot now leads to this member
-                slots[i] = static_cast<std::uint32_t>(k - obj);
+                duplicate = true; // keep the first
                 break;
             }
             if (++distance > index_max_displacement)
@@ -130,7 +129,7 @@ inline void build_object_indexes(document_data& d)
     }
 }
 
-/// the key node of the last member with this key of an indexed object, or
+/// the key node of the first member with this key of an indexed object, or
 /// nullptr
 inline const node* find_indexed(const document_data& d, const node* obj, const char* key, std::size_t n) noexcept
 {

include/nlohmann/detail/view/serializer.hpp

@@ -46,11 +46,6 @@ class output_buffer
     {
         const auto size = static_cast<std::size_t>(m_pos - m_out.data());
         m_out.resize(size);
-        // do not keep a buffer that was sized for a much larger output
-        if (m_out.capacity() > 1024 && m_out.capacity() / 2 > size)
-        {
-            m_out.shrink_to_fit();
-        }
     }
 
     NLOHMANN_VIEW_ALWAYS_INLINE void reserve(std::size_t n)

include/nlohmann/json_view.hpp

@@ -242,7 +242,7 @@ class basic_json_view
     // element access //
     ////////////////////
 
-    /// the value of the member with this key (the last one, should the key
+    /// the value of the member with this key (the first one, should the key
     /// occur more than once); a discarded view if there is none, or if this
     /// is a discarded view (so that v["a"]["b"] is safe). Throws type_error.305
     /// if this is any other value but an object.
@@ -306,7 +306,7 @@ class basic_json_view
         return detail::view::resolve_pointer(*this, detail::json_pointer_access::reference_tokens(ptr), detail::view::pointer_mode::unchecked);
     }
 
-    /// the value of the member with this key (the last one, should the key
+    /// the value of the member with this key (the first one, should the key
     /// occur more than once). Throws type_error.304 if this is not an object,
     /// and out_of_range.403 if there is no such member.
     basic_json_view at(string_view_t key) const
@@ -364,7 +364,7 @@ class basic_json_view
     }
 
     /// the member with this key converted to T, or the default value if there
-    /// is no such member (the last one, should the key occur more than
+    /// is no such member (the first one, should the key occur more than
     /// once). Throws type_error.306 if this is not an object.
     template < typename T, typename std::enable_if < !std::is_same<typename std::decay<T>::type, const char*>::value, int >::type = 0 >
     T value(string_view_t key, const T& default_value) const
@@ -429,7 +429,7 @@ class basic_json_view
     // lookup //
     ////////////
 
-    /// an iterator to the member with this key (the last one, should the
+    /// an iterator to the member with this key (the first one, should the
     /// key occur more than once), or end(); end() also for non-objects
     iterator find(string_view_t key) const
     {
@@ -762,7 +762,7 @@ class basic_json_view
         return (std::min)(m_doc->size - m_node->off, static_cast<std::size_t>(1024) + nodes * 16);
     }
 
-    /// the value of the last member with this key, or a discarded view
+    /// the value of the first member with this key, or a discarded view
     /// (object required)
     NLOHMANN_VIEW_ALWAYS_INLINE basic_json_view lookup(string_view_t key) const noexcept
     {