LibDNS: Remove the 'DNS' prefix from the various type and class names

Since all types and class names live in the DNS namespace, we don't
need to spell it out twice each time.

Userland/Libraries/LibDNS/Name.cpp

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021, Sergey Bugaev <bugaevc@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "Name.h"
+#include <AK/Random.h>
+#include <AK/Vector.h>
+#include <ctype.h>
+
+namespace DNS {
+
+Name::Name(String const& name)
+{
+    if (name.ends_with('.'))
+        m_name = name.substring(0, name.length() - 1);
+    else
+        m_name = name;
+}
+
+Name Name::parse(u8 const* data, size_t& offset, size_t max_offset, size_t recursion_level)
+{
+    if (recursion_level > 4)
+        return {};
+
+    StringBuilder builder;
+    while (true) {
+        if (offset >= max_offset)
+            return {};
+        u8 b = data[offset++];
+        if (b == '\0') {
+            // This terminates the name.
+            return builder.to_string();
+        } else if ((b & 0xc0) == 0xc0) {
+            // The two bytes tell us the offset when to continue from.
+            if (offset >= max_offset)
+                return {};
+            size_t dummy = (b & 0x3f) << 8 | data[offset++];
+            auto rest_of_name = parse(data, dummy, max_offset, recursion_level + 1);
+            builder.append(rest_of_name.as_string());
+            return builder.to_string();
+        } else {
+            // This is the length of a part.
+            if (offset + b >= max_offset)
+                return {};
+            builder.append((char const*)&data[offset], (size_t)b);
+            builder.append('.');
+            offset += b;
+        }
+    }
+}
+
+size_t Name::serialized_size() const
+{
+    if (m_name.is_empty())
+        return 1;
+    return m_name.length() + 2;
+}
+
+void Name::randomize_case()
+{
+    StringBuilder builder;
+    for (char c : m_name) {
+        // Randomize the 0x20 bit in every ASCII character.
+        if (isalpha(c)) {
+            if (get_random_uniform(2))
+                c |= 0x20;
+            else
+                c &= ~0x20;
+        }
+        builder.append(c);
+    }
+    m_name = builder.to_string();
+}
+
+OutputStream& operator<<(OutputStream& stream, Name const& name)
+{
+    auto parts = name.as_string().split_view('.');
+    for (auto& part : parts) {
+        stream << (u8)part.length();
+        stream << part.bytes();
+    }
+    stream << '\0';
+    return stream;
+}
+
+unsigned Name::Traits::hash(Name const& name)
+{
+    return CaseInsensitiveStringTraits::hash(name.as_string());
+}
+
+bool Name::Traits::equals(Name const& a, Name const& b)
+{
+    return CaseInsensitiveStringTraits::equals(a.as_string(), b.as_string());
+}
+
+}