ignore special chars that occurs in tag values

ncmpcpp shouldn't treat '$' characters that
are part of a tag as special format chars.

src/display.cpp

@@ -221,12 +221,17 @@ void Display::Songs(const MPD::Song &s, void *data, Menu<MPD::Song> *menu)
 	if (is_now_playing)
 		*menu << Config.now_playing_prefix;
 	
-	std::string line = s.toString(*static_cast<std::string *>(data));
+	std::string line = s.toString(*static_cast<std::string *>(data), "$");
 	for (std::string::const_iterator it = line.begin(); it != line.end(); ++it)
 	{
 		if (*it == '$')
 		{
-			if (isdigit(*++it))
+			if (++it == line.end()) // end of format
+			{
+				*menu << '$';
+				break;
+			}
+			else if (isdigit(*it)) // color
 			{
 				*menu << Color(*it-'0');
 			}
@@ -240,7 +245,14 @@ void Display::Songs(const MPD::Song &s, void *data, Menu<MPD::Song> *menu)
 				*menu << XY(menu->GetWidth()-buf.Str().length(), menu->Y()) << buf;
 				return;
 			}
-			else
+			else // not a color nor right align, just a random character
+				*menu << *--it;
+		}
+		else if (*it == MPD::Song::FormatEscapeCharacter)
+		{
+			// treat '$' as a normal character if song format escape char is prepended to it
+			if (++it == line.end() || *it != '$')
+				--it;
 			*menu << *it;
 		}
 		else

src/helpers.h

@@ -92,10 +92,17 @@ template <typename C> void String2Buffer(const std::basic_string<C> &s, basic_bu
 {
 	for (typename std::basic_string<C>::const_iterator it = s.begin(); it != s.end(); ++it)
 	{
-		if (*it != '$')
-			buf << *it;
-		else if (isdigit(*++it))
+		if (*it == '$')
+		{
+			if (++it == s.end())
+			{
+				buf << '$';
+				break;
+			}
+			else if (isdigit(*it))
+			{
 				buf << Color(*it-'0');
+			}
 			else
 			{
 				switch (*it)
@@ -113,7 +120,12 @@ template <typename C> void String2Buffer(const std::basic_string<C> &s, basic_bu
 						buf << fmtReverse;
 						break;
 					case '/':
-					switch (*++it)
+						if (++it == s.end())
+						{
+							buf << "$/";
+							break;
+						}
+						switch (*it)
 						{
 							case 'b':
 								buf << fmtBoldEnd;
@@ -127,14 +139,27 @@ template <typename C> void String2Buffer(const std::basic_string<C> &s, basic_bu
 							case 'r':
 								buf << fmtReverseEnd;
 								break;
+							default:
+								buf << '$' << *--it;
+								break;
 						}
 						break;
 					default:
-					buf << *it;
+						buf << *--it;
 						break;
 				}
 			}
 		}
+		else if (*it == MPD::Song::FormatEscapeCharacter)
+		{
+			// treat '$' as a normal character if song format escape char is prepended to it
+			if (++it == s.end() || *it != '$')
+				--it;
+			buf << *it;
+		}
+		else
+			buf << *it;
+	}
 }
 
 template <typename T> void ShowTag(T &buf, const std::string &tag)

src/song.cpp

@@ -305,7 +305,7 @@ void MPD::Song::SetPosition(int pos)
 	itsSong->pos = pos;
 }
 
-std::string MPD::Song::ParseFormat(std::string::const_iterator &it) const
+std::string MPD::Song::ParseFormat(std::string::const_iterator &it, const char *escape_chars) const
 {
 	std::string result;
 	bool has_some_tags = 0;
@@ -314,7 +314,7 @@ std::string MPD::Song::ParseFormat(std::string::const_iterator &it) const
 	{
 		while (*it == '{')
 		{
-			std::string tags = ParseFormat(it);
+			std::string tags = ParseFormat(it, escape_chars);
 			if (!tags.empty())
 			{
 				has_some_tags = 1;
@@ -379,6 +379,10 @@ std::string MPD::Song::ParseFormat(std::string::const_iterator &it) const
 			if (get)
 			{
 				std::string tag = (this->*get)();
+				if (escape_chars) // prepend format escape character to all given chars to escape
+					for (const char *ch = escape_chars; *ch; ++ch)
+						for (size_t i = tag.find(*ch); i != std::string::npos; i = tag.find(*ch, i += 2))
+							tag.replace(i, 1, std::string(1, FormatEscapeCharacter) + ch);
 				if (!tag.empty() && (get != &MPD::Song::GetLength || GetTotalLength()))
 				{
 					has_some_tags = 1;
@@ -402,7 +406,7 @@ std::string MPD::Song::ParseFormat(std::string::const_iterator &it) const
 				--brace_counter;
 		}
 		if (*++it == '|')
-			return ParseFormat(++it);
+			return ParseFormat(++it, escape_chars);
 		else
 			return "";
 	}
@@ -423,10 +427,10 @@ std::string MPD::Song::ParseFormat(std::string::const_iterator &it) const
 	}
 }
 
-std::string MPD::Song::toString(const std::string &format) const
+std::string MPD::Song::toString(const std::string &format, const char *escape_chars) const
 {
 	std::string::const_iterator it = format.begin();
-	return ParseFormat(it);
+	return ParseFormat(it, escape_chars);
 }
 
 MPD::Song &MPD::Song::operator=(const MPD::Song &s)

src/song.h

@@ -78,7 +78,8 @@ namespace MPD
 			void SetNewName(const std::string &name) { itsNewName = name == GetName() ? "" : name; }
 			std::string GetNewName() const { return itsNewName; }
 			
-			std::string toString(const std::string &) const;
+			std::string toString(const std::string &, const char *escape_chars = 0) const;
+			static const char FormatEscapeCharacter = 1;
 			
 			void NullMe() { itsSong = 0; }
 			void CopyPtr(bool copy) { copyPtr = copy; }
@@ -97,7 +98,7 @@ namespace MPD
 			
 		private:
 			void SetHashAndSlash();
-			std::string ParseFormat(std::string::const_iterator &it) const;
+			std::string ParseFormat(std::string::const_iterator &it, const char *escape_chars) const;
 			
 			mpd_Song *itsSong;
 			std::string itsNewName;