types: Flesh out address comparison and string formatting

Change-Id: Ib505232e15e8db012d07759163f780b00ea4b7d3
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/types.hpp b/src/types.hpp
index a78253c..a6011ff 100644
--- a/src/types.hpp
+++ b/src/types.hpp
@@ -1,12 +1,18 @@
 #pragma once
+#include <fmt/core.h>
+#include <net/ethernet.h>
 #include <netinet/in.h>
 #include <systemd/sd-event.h>
 
+#include <algorithm>
+#include <array>
 #include <chrono>
 #include <memory>
 #include <sdeventplus/clock.hpp>
 #include <sdeventplus/utility/timer.hpp>
 #include <string>
+#include <string_view>
+#include <type_traits>
 #include <unordered_map>
 #include <unordered_set>
 #include <variant>
@@ -36,7 +42,7 @@
 using EventPtr = std::unique_ptr<sd_event, EventDeleter>;
 
 // Byte representations for common address types in network byte order
-using InAddrAny = std::variant<struct in_addr, struct in6_addr>;
+using InAddrAny = std::variant<in_addr, in6_addr>;
 
 using Timer = sdeventplus::utility::Timer<sdeventplus::ClockId::Monotonic>;
 
@@ -62,6 +68,94 @@
     return seed ^ (std::hash<T>{}(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2));
 }
 
+namespace detail
+{
+
+template <typename T>
+constexpr bool vcontains() noexcept
+{
+    return false;
+}
+
+template <typename T, typename V, typename... Vs>
+constexpr bool vcontains() noexcept
+{
+    return vcontains<T, Vs...>() || std::is_same_v<T, V>;
+}
+
+template <typename T, typename... Types>
+constexpr std::enable_if_t<vcontains<T, Types...>(), bool>
+    veq(T t, std::variant<Types...> v) noexcept
+{
+    return std::visit(
+        [t](auto v) {
+            if constexpr (std::is_same_v<T, decltype(v)>)
+            {
+                return v == t;
+            }
+            else
+            {
+                return false;
+            }
+        },
+        v);
+}
+
+template <typename T>
+struct AddrBufMaker
+{
+};
+
+template <>
+struct AddrBufMaker<ether_addr>
+{
+  public:
+    std::string_view operator()(ether_addr val) noexcept;
+
+  private:
+    std::array<char, /*octet*/ 2 * /*octets*/ 6 + /*seps*/ 5> buf;
+};
+
+template <>
+struct AddrBufMaker<in_addr>
+{
+  public:
+    std::string_view operator()(in_addr val) noexcept;
+
+  private:
+    std::array<char, /*octet*/ 3 * /*octets*/ 4 + /*seps*/ 3> buf;
+};
+
+template <>
+struct AddrBufMaker<in6_addr>
+{
+  public:
+    std::string_view operator()(in6_addr val) noexcept;
+
+  private:
+    std::array<char, /*hextet*/ 4 * /*hextets*/ 8 + /*seps*/ 7> buf;
+};
+
+template <typename BufMaker>
+struct FormatFromBuf
+{
+  private:
+    fmt::formatter<std::string_view> formatter;
+
+  public:
+    template <typename ParseContext>
+    constexpr auto parse(ParseContext& ctx)
+    {
+        return ctx.begin();
+    }
+
+    template <typename FormatContext>
+    auto format(auto v, FormatContext& ctx) const
+    {
+        return formatter.format(BufMaker{}(v), ctx);
+    }
+};
+} // namespace detail
 } // namespace network
 } // namespace phosphor
 
@@ -73,3 +167,116 @@
         return std::apply(phosphor::network::hash_multi<Ts...>, t);
     }
 };
+
+namespace fmt
+{
+template <>
+struct formatter<ether_addr>
+    : phosphor::network::detail::FormatFromBuf<
+          phosphor::network::detail::AddrBufMaker<ether_addr>>
+{
+};
+template <>
+struct formatter<in_addr>
+    : phosphor::network::detail::FormatFromBuf<
+          phosphor::network::detail::AddrBufMaker<in_addr>>
+{
+};
+template <>
+struct formatter<in6_addr>
+    : phosphor::network::detail::FormatFromBuf<
+          phosphor::network::detail::AddrBufMaker<in6_addr>>
+{
+};
+template <>
+struct formatter<phosphor::network::InAddrAny>
+{
+  private:
+    fmt::formatter<std::string_view> formatter;
+
+  public:
+    template <typename ParseContext>
+    constexpr auto parse(ParseContext& ctx)
+    {
+        return ctx.begin();
+    }
+
+    template <typename FormatContext>
+    auto format(auto v, FormatContext& ctx) const
+    {
+        return std::visit(
+            [&](auto v) {
+                auto abm =
+                    phosphor::network::detail::AddrBufMaker<decltype(v)>{};
+                return formatter.format(abm(v), ctx);
+            },
+            v);
+    }
+};
+} // namespace fmt
+
+namespace std
+{
+string to_string(ether_addr value);
+string to_string(in_addr value);
+string to_string(in6_addr value);
+string to_string(phosphor::network::InAddrAny value);
+} // namespace std
+
+constexpr bool operator==(ether_addr lhs, ether_addr rhs) noexcept
+{
+    return std::equal(lhs.ether_addr_octet, lhs.ether_addr_octet + 6,
+                      rhs.ether_addr_octet);
+}
+
+constexpr bool operator==(in_addr lhs, in_addr rhs) noexcept
+{
+    return lhs.s_addr == rhs.s_addr;
+}
+
+constexpr bool operator==(in6_addr lhs, in6_addr rhs) noexcept
+{
+    return std::equal(lhs.s6_addr32, lhs.s6_addr32 + 4, rhs.s6_addr32);
+}
+
+template <typename T>
+constexpr std::enable_if_t<!std::is_same_v<phosphor::network::InAddrAny, T>,
+                           bool>
+    operator==(phosphor::network::InAddrAny lhs, T rhs) noexcept
+{
+    return phosphor::network::detail::veq(rhs, lhs);
+}
+
+template <typename CharT, typename Traits>
+std::basic_ostream<CharT, Traits>&
+    operator<<(std::basic_ostream<CharT, Traits>& os, ether_addr v)
+{
+    return os << phosphor::network::detail::AddrBufMaker<ether_addr>{}(v);
+}
+
+template <typename CharT, typename Traits>
+std::basic_ostream<CharT, Traits>&
+    operator<<(std::basic_ostream<CharT, Traits>& os, in_addr v)
+{
+    return os << phosphor::network::detail::AddrBufMaker<in_addr>{}(v);
+}
+
+template <typename CharT, typename Traits>
+std::basic_ostream<CharT, Traits>&
+    operator<<(std::basic_ostream<CharT, Traits>& os, in6_addr v)
+{
+    return os << phosphor::network::detail::AddrBufMaker<in6_addr>{}(v);
+}
+
+template <typename CharT, typename Traits>
+std::basic_ostream<CharT, Traits>&
+    operator<<(std::basic_ostream<CharT, Traits>& os,
+               phosphor::network::InAddrAny v)
+{
+    return os << std::visit(
+               [](auto v) {
+                   return phosphor::network::detail::AddrBufMaker<
+                       decltype(v)>{}(v);
+               },
+               v);
+}