From 5eb8e3eac010c322a23c3f351f90177639f0df5a Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 22 Mar 2020 11:19:08 +0000
Subject: Wrap Formatter with as FormatterDetail

Fixes some signedness issues around searching strings.
---
 libadhocutil/compileTimeFormatter.h                | 36 ++++++++++++++--------
 .../unittests/testCompileTimeFormatter.cpp         | 26 ++++++++--------
 2 files changed, 37 insertions(+), 25 deletions(-)

diff --git a/libadhocutil/compileTimeFormatter.h b/libadhocutil/compileTimeFormatter.h
index 09fdb6a..0a86946 100644
--- a/libadhocutil/compileTimeFormatter.h
+++ b/libadhocutil/compileTimeFormatter.h
@@ -3,6 +3,7 @@
 
 #include <sstream>
 #include <cstring>
+#include <optional>
 #include <array>
 #include <boost/preprocessor/variadic/size.hpp>
 #include "unique.h"
@@ -26,24 +27,32 @@ namespace AdHoc {
 	template<CtfString S>
 	static constexpr auto strlen()
 	{
-		auto off = 0;
+		auto off = 0U;
 		while (S[off]) { ++off; }
 		return off;
 	}
 
-	template<CtfString S, auto n, auto start = 0, auto L = strlen<S>()>
-	static constexpr auto strchr()
+	template<typename char_type>
+	static constexpr auto strlen(const char_type * S)
+	{
+		auto off = 0U;
+		while (S[off]) { ++off; }
+		return off;
+	}
+
+	template<CtfString S, auto n, auto start = 0U, auto L = strlen<S>()>
+	static constexpr std::optional<decltype(start)> strchr()
 	{
 		static_assert(start <= L);
 		decltype(start) off = start;
 		while (off < L && S[off] != n) { ++off; }
 		if (off == L) {
-			return -1;
+			return {};
 		}
 		return off;
 	}
 
-	template<CtfString S, auto n, auto start = 0, auto L = strlen<S>()>
+	template<CtfString S, auto n, auto start = 0U, auto L = strlen<S>()>
 	static constexpr decltype(L) strchrnul()
 	{
 		decltype(start) off = start;
@@ -51,7 +60,7 @@ namespace AdHoc {
 		return off;
 	}
 
-	template<CtfString S, decltype(strlen<S>())> class Formatter;
+	template<CtfString S, const auto L> class FormatterDetail;
 
 	/// Template used to apply parameters to a stream.
 	template<CtfString S, auto L, auto pos, typename stream, typename, auto ...>
@@ -71,7 +80,7 @@ namespace AdHoc {
 		template<typename ... Pn>
 		static inline void next(stream & s, const Pn & ... pn)
 		{
-			Formatter<S, L>::template Parser<stream, pos + 1, Pn...>::run(s, pn...);
+			FormatterDetail<S, L>::template Parser<stream, pos + 1, Pn...>::run(s, pn...);
 		}
 	};
 
@@ -121,8 +130,8 @@ namespace AdHoc {
 	 * Compile time string formatter.
 	 * @param S the format string.
 	 */
-	template <CtfString S, decltype(strlen<S>()) L = strlen<S>()>
-	class Formatter {
+	template <CtfString S, const auto L>
+	class FormatterDetail {
 		private:
 			using strlen_t = decltype(strlen<S>());
 			template<CtfString, auto, auto, typename> friend struct StreamWriterBase;
@@ -161,7 +170,7 @@ namespace AdHoc {
 			template<typename stream, typename ... Pn>
 			static inline stream & write(stream & s, const Pn & ... pn)
 			{
-				return Parser<stream, 0, Pn...>::run(s, pn...);
+				return Parser<stream, 0U, Pn...>::run(s, pn...);
 			}
 			/**
 			 * Write the result of formatting to the given stream.
@@ -193,7 +202,7 @@ namespace AdHoc {
 					}
 					return s;
 				}
-				template<strlen_t ph, strlen_t off = 0, auto ... Pck>
+				template<strlen_t ph, strlen_t off = 0U, auto ... Pck>
 				static inline void packAndWrite(stream & s, const Pn & ... pn)
 				{
 					if constexpr (ph + off == L || sizeof...(Pck) == 32) {
@@ -220,12 +229,15 @@ namespace AdHoc {
 		};
 		template<typename T, T ... t> inline auto operator""_fmt() noexcept
 		{
-			return AdHoc::Formatter<FMT<T, t...>::__FMT, sizeof...(t)>();
+			return AdHoc::FormatterDetail<FMT<T, t...>::__FMT, sizeof...(t)>();
 		}
 #ifdef __clang__
 #pragma clang diagnostic pop
 #endif
 	}
+
+	template <const auto & S, decltype(strlen<S>()) L = strlen<S>()>
+	class Formatter : public FormatterDetail<S, L> { };
 }
 
 #define AdHocFormatterTypedef(name, str, id) \
diff --git a/libadhocutil/unittests/testCompileTimeFormatter.cpp b/libadhocutil/unittests/testCompileTimeFormatter.cpp
index a19e588..ba8a46f 100644
--- a/libadhocutil/unittests/testCompileTimeFormatter.cpp
+++ b/libadhocutil/unittests/testCompileTimeFormatter.cpp
@@ -84,16 +84,16 @@ static_assert(strlen<formatEdgeCaseFormatLonely>() == 2);
 static_assert(strlen<formatStringLiteral>() == 7);
 static_assert(strlen<formatStringLong>() == 246);
 
-static_assert(strchr<formatEdgeCaseEmpty, 't'>() == -1);
-static_assert(strchr<formatEdgeCaseSingle, 't'>() == -1);
-static_assert(strchr<formatEdgeCaseSingle, '1'>() == 0);
-static_assert(strchr<formatEdgeCaseFormatLonely, '%'>() == 0);
-static_assert(strchr<formatEdgeCaseFormatLonely, '?'>() == 1);
-static_assert(strchr<formatStringLiteral, 'e'>() == 3);
-static_assert(strchr<formatStringLiteral, 'f'>() == -1);
-static_assert(strchr<formatStringLiteral, 'e', 3>() == 3);
-static_assert(strchr<formatStringLiteral, 'e', 4>() == -1);
-static_assert(strchr<formatStringLiteral, 'f', 3>() == -1);
+static_assert(!strchr<formatEdgeCaseEmpty, 't'>());
+static_assert(!strchr<formatEdgeCaseSingle, 't'>());
+static_assert(*strchr<formatEdgeCaseSingle, '1'>() == 0);
+static_assert(*strchr<formatEdgeCaseFormatLonely, '%'>() == 0);
+static_assert(*strchr<formatEdgeCaseFormatLonely, '?'>() == 1);
+static_assert(*strchr<formatStringLiteral, 'e'>() == 3);
+static_assert(!strchr<formatStringLiteral, 'f'>());
+static_assert(*strchr<formatStringLiteral, 'e', 3U>() == 3);
+static_assert(!strchr<formatStringLiteral, 'e', 4U>());
+static_assert(!strchr<formatStringLiteral, 'f', 3U>());
 
 static_assert(strchrnul<formatEdgeCaseEmpty, 't'>() == 0);
 static_assert(strchrnul<formatEdgeCaseSingle, 't'>() == 1);
@@ -102,9 +102,9 @@ static_assert(strchrnul<formatEdgeCaseFormatLonely, '%'>() == 0);
 static_assert(strchrnul<formatEdgeCaseFormatLonely, '?'>() == 1);
 static_assert(strchrnul<formatStringLiteral, 'e'>() == 3);
 static_assert(strchrnul<formatStringLiteral, 'f'>() == 7);
-static_assert(strchrnul<formatStringLiteral, 'e', 3>() == 3);
-static_assert(strchrnul<formatStringLiteral, 'e', 4>() == 7);
-static_assert(strchrnul<formatStringLiteral, 'f', 3>() == 7);
+static_assert(strchrnul<formatStringLiteral, 'e', 3U>() == 3);
+static_assert(strchrnul<formatStringLiteral, 'e', 4U>() == 7);
+static_assert(strchrnul<formatStringLiteral, 'f', 3U>() == 7);
 
 static_assert(strchrnul<formatEdgeCaseEmpty, 't'>() == 0);
 static_assert(strchrnul<formatEdgeCaseSingle, 't'>() == 1);
-- 
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