From 772bd173742753c1cc7b21ca79e20fab7f36abd3 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Fri, 30 Dec 2016 22:38:23 +0000
Subject: Refactor to reduce AdHoc namespace polution

---
 libadhocutil/compileTimeFormatter.h | 198 +++++++++++++++++++-----------------
 1 file changed, 104 insertions(+), 94 deletions(-)

diff --git a/libadhocutil/compileTimeFormatter.h b/libadhocutil/compileTimeFormatter.h
index 7734f9c..4f980d2 100644
--- a/libadhocutil/compileTimeFormatter.h
+++ b/libadhocutil/compileTimeFormatter.h
@@ -7,51 +7,16 @@ namespace AdHoc {
 	/// @cond
 	constexpr int WRAP_AT = 120;
 
-	template <int, char...> struct Buffer { };
-
-	template <const char * const & S, int start, int offset, char ...>
-	struct Upto {
-		template<typename stream>
-		static auto scan(stream &, const Buffer<start> & f)
-		{
-			return f;
-		}
-	};
-	template <const char * const & S, int start, int offset, char s0, char... sn>
-	struct Upto<S, start, offset, s0, sn...> {
-		template<typename stream, int len, char... sm>
-		static auto scan(stream & s, const Buffer<len, sm...> &)
-		{
-			return Upto<S, start, offset + 1, sn...>::scan(s, Buffer<len, sm..., s0>());
-		}
-	};
-	template <const char * const & S, int start, char... sn>
-	struct UptoWrite {
-		template<typename stream, int len, char... sm>
-		static auto scan(stream & s, const Buffer<len, sm...> &)
-		{
-			s.write(S + start, sizeof...(sm));
-			return Buffer<sizeof...(sm), sn...>();
-		}
-	};
-	template <const char * const & S, int start, int offset, char... sn>
-	struct Upto<S, start, offset, '%', sn...> : public UptoWrite<S, start, '%', sn...> { };
-	template <const char * const & S, int start, int offset, char... sn>
-	struct Upto<S, start, offset, 0, sn...> : public UptoWrite<S, start, 0, sn...> { };
-	template <const char * const & S, int start, char s0, char... sn>
-	struct Upto<S, start, WRAP_AT, s0, sn...> : public UptoWrite<S, start, s0, sn...> { };
-	template <const char * const & S, int start, char... sn>
-	struct Upto<S, start, WRAP_AT, '%', sn...> : public UptoWrite<S, start, '%', sn...> { };
-	template <const char * const & S, int start, char... sn>
-	struct Upto<S, start, WRAP_AT, 0, sn...> : public UptoWrite<S, start, 0, sn...> { };
+	namespace FormatterImpl {
+		template <bool, char...> struct ParserBuffer { };
+		template <int, char...> struct Buffer { };
+	}
 
 	template <const char * const & S, int start, typename stream, char ... sn>
 	struct StreamWriter {
 		template<typename ... Pn>
-		static void write(stream & s, const Pn & ... pn)
-		{
-			next(s, Upto<S, start, 0, sn...>::scan(s, Buffer<0>()), pn...);
-		}
+		static void write(stream & s, const Pn & ... pn);
+
 		template<typename ... Pn, int len, char... ssn, template <int, char...> class Buffer>
 		static void next(stream & s, const Buffer<len, ssn...>&, const Pn & ... pn)
 		{
@@ -121,63 +86,99 @@ namespace AdHoc {
 		static int err;
 	};
 
-	template <bool, char...> struct ParserBuffer { };
-
-	template <const char * const & S, int offset, int roffset, char s0, char ... sn>
-	struct Parser {
-		static auto parse()
-		{
-			return append(innerparse());
-		}
-		static auto innerparse()
-		{
-			return Parser<S, offset + 1, roffset + 1, S[offset + 1], sn..., s0>::innerparse();
-		}
-		template<char...ssn>
-		static auto append(const ParserBuffer<true, ssn...> & b)
-		{
-			return join(b, Parser<S, offset + 1 + WRAP_AT, 0, S[offset + 1 + WRAP_AT]>::parse());
-		}
-		template<char...ssn>
-		static auto append(const ParserBuffer<false, ssn...> & b)
-		{
-			return b;
-		}
-		template<bool more, char...ssn, char...ssm>
-		static auto join(const ParserBuffer<true, ssn...> &, const ParserBuffer<more, ssm...> &)
-		{
-			return ParserBuffer<more, ssn..., ssm...>();
-		}
-	};
-
-	template <const char * const & S, bool more, char ... sn>
-	struct ParserBase {
-		static auto parse()
-		{
-			return innerparse();
-		}
-		static auto innerparse()
-		{
-			return ParserBuffer<more, sn...>();
-		}
-	};
-
-	template <const char * const & S, int offset, char s0, char ... sn>
-	struct Parser<S, offset, WRAP_AT, s0, sn...> : public ParserBase<S, true, sn..., s0> { };
-
-	template <const char * const & S, int offset, char ... sn>
-	struct Parser<S, offset, WRAP_AT, 0, sn...> : public ParserBase<S, true, sn..., 0> { };
-
-	template <const char * const & S, int offset, int roffset, char ... sn>
-	struct Parser<S, offset, roffset, 0, sn...> : public ParserBase<S, false, sn..., 0>{ };
-	/// @endcond
-
 	/**
 	 * Compile time string formatter.
 	 * @param S the format string.
 	 */
 	template <const char * const & S>
 	class Formatter {
+		private:
+			template<const char * const &, int, typename, char ...> friend struct StreamWriter;
+
+			template <int start, int offset, char ...>
+			struct Upto {
+				template<typename stream>
+				static auto scan(stream &, const FormatterImpl::Buffer<start> & f)
+				{
+					return f;
+				}
+			};
+			template <int start, int offset, char s0, char... sn>
+			struct Upto<start, offset, s0, sn...> {
+				template<typename stream, int len, char... sm>
+				static auto scan(stream & s, const FormatterImpl::Buffer<len, sm...> &)
+				{
+					return Upto<start, offset + 1, sn...>::scan(s, FormatterImpl::Buffer<len, sm..., s0>());
+				}
+			};
+			template <int start, char... sn>
+			struct UptoWrite {
+				template<typename stream, int len, char... sm>
+				static auto scan(stream & s, const FormatterImpl::Buffer<len, sm...> &)
+				{
+					s.write(S + start, sizeof...(sm));
+					return FormatterImpl::Buffer<sizeof...(sm), sn...>();
+				}
+			};
+			template <int start, int offset, char... sn>
+			struct Upto<start, offset, '%', sn...> : public UptoWrite<start, '%', sn...> { };
+			template <int start, int offset, char... sn>
+			struct Upto<start, offset, 0, sn...> : public UptoWrite<start, 0, sn...> { };
+			template <int start, char s0, char... sn>
+			struct Upto<start, WRAP_AT, s0, sn...> : public UptoWrite<start, s0, sn...> { };
+			template <int start, char... sn>
+			struct Upto<start, WRAP_AT, '%', sn...> : public UptoWrite<start, '%', sn...> { };
+			template <int start, char... sn>
+			struct Upto<start, WRAP_AT, 0, sn...> : public UptoWrite<start, 0, sn...> { };
+
+			template <int offset, int roffset, char s0, char ... sn>
+			struct Parser {
+				static auto parse()
+				{
+					return append(innerparse());
+				}
+				static auto innerparse()
+				{
+					return Parser<offset + 1, roffset + 1, S[offset + 1], sn..., s0>::innerparse();
+				}
+				template<char...ssn>
+				static auto append(const FormatterImpl::ParserBuffer<true, ssn...> & b)
+				{
+					return join(b, Parser<offset + 1 + WRAP_AT, 0, S[offset + 1 + WRAP_AT]>::parse());
+				}
+				template<char...ssn>
+				static auto append(const FormatterImpl::ParserBuffer<false, ssn...> & b)
+				{
+					return b;
+				}
+				template<bool more, char...ssn, char...ssm>
+				static auto join(const FormatterImpl::ParserBuffer<true, ssn...> &, const FormatterImpl::ParserBuffer<more, ssm...> &)
+				{
+					return FormatterImpl::ParserBuffer<more, ssn..., ssm...>();
+				}
+			};
+
+			template <bool more, char ... sn>
+			struct ParserBase {
+				static auto parse()
+				{
+					return innerparse();
+				}
+				static auto innerparse()
+				{
+					return FormatterImpl::ParserBuffer<more, sn...>();
+				}
+			};
+
+			template <int offset, char s0, char ... sn>
+			struct Parser<offset, WRAP_AT, s0, sn...> : public ParserBase<true, sn..., s0> { };
+
+			template <int offset, char ... sn>
+			struct Parser<offset, WRAP_AT, 0, sn...> : public ParserBase<true, sn..., 0> { };
+
+			template <int offset, int roffset, char ... sn>
+			struct Parser<offset, roffset, 0, sn...> : public ParserBase<false, sn..., 0>{ };
+
 		public:
 			/**
 			 * Get a string containing the result of formatting.
@@ -188,7 +189,7 @@ namespace AdHoc {
 			static std::string get(const Pn & ... pn)
 			{
 				std::stringstream s;
-				return run(Parser<S, 0, 0, *S>::parse(), s, pn...).str();
+				return run(Parser<0, 0, *S>::parse(), s, pn...).str();
 			}
 
 			/**
@@ -200,7 +201,7 @@ namespace AdHoc {
 			template<typename stream, typename ... Pn>
 			static stream & write(stream & s, const Pn & ... pn)
 			{
-				return run(Parser<S, 0, 0, *S>::parse(), s, pn...);
+				return run(Parser<0, 0, *S>::parse(), s, pn...);
 			}
 
 		private:
@@ -211,6 +212,15 @@ namespace AdHoc {
 				return s;
 			}
 	};
+
+	/// @cond
+	template <const char * const & S, int start, typename stream, char ... sn>
+	template<typename ... Pn>
+	void StreamWriter<S, start, stream, sn...>::write(stream & s, const Pn & ... pn)
+	{
+		next(s, Formatter<S>::template Upto<start, 0, sn...>::scan(s, FormatterImpl::Buffer<0>()), pn...);
+	}
+	/// @endcond
 }
 
 #define AdHocFormatterTypedef(name, str, id) \
-- 
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