Fixed compilation on AVR boards

Turns out AVR/Arduino doesn't necessarily have a complete c++ library. Which includes std::forward, so here I include a custom implementation in the hopes that this library will _just work_.

I was tempted by the idea of using the standard library implementation of std::forward if it were defined, but without the type traits library, I'm not sure it's possible, so instead this implementation gets used for everything (even if std::forward exists)

src/DF-Print.h

@@ -32,9 +32,8 @@
 #	define DEBUG_PRINTLN(format, ...)
 #endif
 
-#include <cstring>
-
 #include "DF-PrintInternal.h"
+#include "DF-StdUtility.h"
 
 namespace DF
 {
@@ -59,8 +58,8 @@ namespace DF
 	{
 		size_t charactersPrinted = 0;
 
-		charactersPrinted += Internal::PrintTextWithArgument(format, std::forward<Arg>(arg));
-		charactersPrinted += Print(format, std::forward<Args>(args)...);
+		charactersPrinted += Internal::PrintTextWithArgument(format, DF::forward<Arg>(arg));
+		charactersPrinted += Print(format, DF::forward<Args>(args)...);
 
 		return charactersPrinted;
 	}
@@ -70,7 +69,7 @@ namespace DF
 	{
 		size_t charactersPrinted = 0;
 
-		charactersPrinted += Print(format, std::forward<Args>(args)...);
+		charactersPrinted += Print(format, DF::forward<Args>(args)...);
 
 		return charactersPrinted;
 	}
@@ -80,7 +79,7 @@ namespace DF
 	{
 		size_t charactersPrinted = 0;
 
-		charactersPrinted += Print(format, std::forward<Args>(args)...);
+		charactersPrinted += Print(format, DF::forward<Args>(args)...);
 		charactersPrinted += Serial.println("");
 		// Alternatively, could do Serial.write("\r\n"); - more efficient? Is it worth making that string be read from PROGMEM?
 

src/DF-PrintInternal.h

@@ -26,6 +26,11 @@
 
 #include <Arduino.h>
 
+// Some Arduino platform implementations do not comprehensively cover the C++ standard, so we need to use string.h instead of cstring
+#include <string.h>
+
+#include "DF-StdUtility.h"
+
 namespace DF
 {
 	namespace Internal
@@ -35,7 +40,7 @@ namespace DF
 		// Format is modified to remove the text that was printed
 		inline size_t PrintTextBeforeFirstArgumentSpecifier(const char*& format)
 		{
-			const char* argStart = std::strchr(format, '{');
+			const char* argStart = strchr(format, '{');
 
 			if (!argStart)
 			{
@@ -55,12 +60,12 @@ namespace DF
 		template <typename Arg>
 		inline size_t PrintArgumentInPlaceOfSpecifier(const char*& format, Arg&& arg)
 		{
-			const char* argEnd = std::strchr(format, '}');
+			const char* argEnd = strchr(format, '}');
 
 			if (argEnd)
 				format = argEnd + 1;
 
-			return Serial.print(std::forward<Arg>(arg));
+			return Serial.print(DF::forward<Arg>(arg));
 		}
 
 		// This will print All the text before an argument specifier (e.g. {0}),
@@ -79,7 +84,7 @@ namespace DF
 			size_t charactersPrinted = 0;
 
 			charactersPrinted += PrintTextBeforeFirstArgumentSpecifier(format);
-			charactersPrinted += PrintArgumentInPlaceOfSpecifier(format, std::forward<Arg>(arg));
+			charactersPrinted += PrintArgumentInPlaceOfSpecifier(format, DF::forward<Arg>(arg));
 			charactersPrinted += PrintTextBeforeFirstArgumentSpecifier(format);
 
 			return charactersPrinted;

src/DF-StdUtility.h

@@ -0,0 +1,64 @@
+/*
+* MIT License
+* Copyright (c) 2022 Daniel Neve
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to deal
+* in the Software without restriction, including without limitation the rights
+* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+* copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in all
+* copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+* SOFTWARE.
+*/
+
+#ifndef __DF_STD_UTILITY_INTERNAL_H__
+#define __DF_STD_UTILITY_INTERNAL_H__
+
+// This exists because not every arduino platform implements std::forward
+namespace DF
+{
+	template <typename T>
+	struct remove_reference
+	{
+		using type = T;
+	};
+
+	template <typename T>
+	struct remove_reference<T&>
+	{
+		using type = T;
+	};
+
+	template <typename T>
+	struct remove_reference<T&&>
+	{
+		using type = T;
+	};
+
+	template <typename T>
+	using remove_reference_t = typename remove_reference<T>::type;
+
+	template <typename T>
+	constexpr T&& forward(remove_reference_t<T>& arg) noexcept
+	{
+		return static_cast<T&&>(arg);
+	}
+
+	template <typename T>
+	constexpr T&& forward(remove_reference_t<T>&& arg) noexcept
+	{
+		return static_cast<T&&>(arg);
+	}
+}
+
+#endif // __DF_STD_UTILITY_INTERNAL_H__