From e30ab84ccc8ad19e181f08c38e96a15bcb5e9c98 Mon Sep 17 00:00:00 2001
From: mutouyun <orz@orzz.org>
Date: Tue, 7 Jan 2025 17:37:58 +0800
Subject: [PATCH] Added fmt support for `byte`

---
 include/libipc/imp/byte.h | 15 +++++++++++++++
 test/imp/test_imp_fmt.cpp | 20 ++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/libipc/imp/byte.h b/include/libipc/imp/byte.h
index 69da411..dec5369 100644
--- a/include/libipc/imp/byte.h
+++ b/include/libipc/imp/byte.h
@@ -11,6 +11,7 @@
 
 #include "libipc/imp/detect_plat.h"
 #include "libipc/imp/span.h"
+#include "libipc/imp/fmt.h"
 
 #if defined(LIBIPC_CPP_17) && defined(__cpp_lib_byte)
 #define LIBIPC_CPP_LIB_BYTE_
@@ -160,4 +161,18 @@ auto as_bytes(span<T> s) noexcept -> span<Byte> {
   return {byte_cast(s.data()), s.size_bytes()};
 }
 
+/// \brief Custom defined fmt_to method for imp::fmt
+namespace detail_tag_invoke {
+
+inline bool tag_invoke(decltype(ipc::fmt_to), fmt_context &ctx, ipc::byte b) {
+  return ipc::to_string(ctx, static_cast<std::uint8_t>(b), "02x");
+}
+
+template <typename T, 
+          typename = std::enable_if_t<std::is_same<std::decay_t<T>, ipc::byte>::value>>
+bool tag_invoke(decltype(ipc::fmt_to), fmt_context &ctx, fmt_ref<T> arg) noexcept {
+  return ipc::to_string(ctx, static_cast<std::uint8_t>(arg.param), arg.fstr);
+}
+
+} // namespace detail_tag_invoke
 } // namespace ipc
diff --git a/test/imp/test_imp_fmt.cpp b/test/imp/test_imp_fmt.cpp
index 04acd6d..be9eb15 100644
--- a/test/imp/test_imp_fmt.cpp
+++ b/test/imp/test_imp_fmt.cpp
@@ -6,6 +6,8 @@
 #include "test.h"
 
 #include "libipc/imp/fmt.h"
+#include "libipc/imp/byte.h"
+#include "libipc/imp/span.h"
 
 TEST(fmt, spec) {
   EXPECT_STREQ(ipc::spec("hello")(123).fstr.data(), "hello");
@@ -123,3 +125,21 @@ bool tag_invoke(decltype(ipc::fmt_to), ipc::fmt_context &, foo arg) noexcept(fal
 TEST(fmt, throw) {
   EXPECT_THROW(std::ignore = ipc::fmt(foo{}), foo);
 }
+
+TEST(fmt, byte) {
+  {
+    ipc::byte b1{}, b2(31);
+    EXPECT_EQ(ipc::fmt(b1), "00");
+    EXPECT_EQ(ipc::fmt(b2), "1f");
+    EXPECT_EQ(ipc::fmt(ipc::spec("03X")(b2)), "01F");
+  }
+  {
+    ipc::byte bs[] {31, 32, 33, 34, 35, 36, 37, 38};
+    EXPECT_EQ(ipc::fmt(ipc::make_span(bs)), "1f 20 21 22 23 24 25 26");
+  }
+}
+
+TEST(fmt, span) {
+  EXPECT_EQ(ipc::fmt(ipc::span<int>{}), "");
+  EXPECT_EQ(ipc::fmt(ipc::make_span({1, 3, 2, 4, 5, 6, 7})), "1 3 2 4 5 6 7");
+}