From 3fd12ff38ddfea869331bfec439307f2315ff11d Mon Sep 17 00:00:00 2001
From: Kefu Chai <tchaikov@gmail.com>
Date: Sun, 21 Aug 2022 08:23:00 +0800
Subject: [PATCH] include/denc: redefine is_const_iterator

to just check for the return type of `it.get_pos_add(n)`, this
is exactly what we expect from a buffer::ptr::const_iterator.
it is more specific and less confusing.

Signed-off-by: Kefu Chai <tchaikov@gmail.com>
---
 src/include/denc.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/include/denc.h b/src/include/denc.h
index 96b7e7c099f..b8982fa2110 100644
--- a/src/include/denc.h
+++ b/src/include/denc.h
@@ -26,6 +26,7 @@
 
 #include <array>
 #include <cstring>
+#include <concepts>
 #include <map>
 #include <optional>
 #include <set>
@@ -283,8 +284,9 @@ using underlying_type_t = typename underlying_type<T>::type;
 }
 
 template<class It>
-concept is_const_iterator =
-std::is_const_v<std::remove_pointer_t<typename It::pointer>>;
+concept is_const_iterator = requires(It& it, size_t n) {
+  { it.get_pos_add(n) } -> std::same_as<const char*>;
+};
 
 template<typename T, is_const_iterator It>
 const T& get_pos_add(It& i) {
-- 
2.39.5