--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/goodjava/bbcode/BBCode.java	Thu Jun 30 20:04:34 2022 -0600
@@ -0,0 +1,334 @@
+package goodjava.bbcode;
+
+import java.util.List;
+import java.util.ArrayList;
+import goodjava.parser.Parser;
+
+
+public final class BBCode {
+
+	public enum Target { HTML, TEXT }
+
+	public interface Quoter {
+		public String quote(Target target,String text,String param);
+	}
+
+	public static final Quoter defaultQuoter = new Quoter() {
+		public String quote(Target target,String text,String param) {
+			StringBuilder sb = new StringBuilder();
+			sb.append( "<blockquote>" );
+			if( param != null ) {
+				sb.append( htmlEncode(param) );
+				sb.append( " wrote:\n" );
+			}
+			sb.append( text );
+			sb.append( "</blockquote>" );
+			return sb.toString();
+		}
+	};
+
+	public Target target = Target.HTML;
+	public Quoter quoter = defaultQuoter;
+	private final Parser parser;
+
+	public BBCode(String text) {
+		this.parser = new Parser(text);
+	}
+
+	public String parse() {
+		StringBuilder sb = new StringBuilder();
+		StringBuilder text = new StringBuilder();
+		while( !parser.endOfInput() ) {
+			String block = parseBlock();
+			if( block != null ) {
+				sb.append( textToString(text) );
+				sb.append(block);
+			} else {
+				text.append( parser.currentChar() );
+				parser.anyChar();
+			}
+		}
+		sb.append( textToString(text) );
+		return sb.toString();
+	}
+
+	private String parseWellFormed() {
+		StringBuilder sb = new StringBuilder();
+		StringBuilder text = new StringBuilder();
+		while( !parser.endOfInput() ) {
+			String block = parseBlock();
+			if( block != null ) {
+				sb.append( textToString(text) );
+				sb.append(block);
+				continue;
+			}
+			if( couldBeTag() )
+				break;
+			text.append( parser.currentChar() );
+			parser.anyChar();
+		}
+		sb.append( textToString(text) );
+		return sb.toString();
+	}
+
+	private String textToString(StringBuilder text) {
+		String s = text.toString();
+		text.setLength(0);
+		if( target == Target.HTML )
+			s = htmlEncode(s);
+		return s;
+	}
+
+	private boolean couldBeTag() {
+		if( parser.currentChar() != '[' )
+			return false;
+		return parser.testIgnoreCase("[b]")
+			|| parser.testIgnoreCase("[/b]")
+			|| parser.testIgnoreCase("[i]")
+			|| parser.testIgnoreCase("[/i]")
+			|| parser.testIgnoreCase("[u]")
+			|| parser.testIgnoreCase("[/u]")
+			|| parser.testIgnoreCase("[url]")
+			|| parser.testIgnoreCase("[url=")
+			|| parser.testIgnoreCase("[/url]")
+			|| parser.testIgnoreCase("[code]")
+			|| parser.testIgnoreCase("[/code]")
+			|| parser.testIgnoreCase("[img]")
+			|| parser.testIgnoreCase("[/img]")
+			|| parser.testIgnoreCase("[color=")
+			|| parser.testIgnoreCase("[/color]")
+			|| parser.testIgnoreCase("[size=")
+			|| parser.testIgnoreCase("[/size]")
+			|| parser.testIgnoreCase("[youtube]")
+			|| parser.testIgnoreCase("[/youtube]")
+			|| parser.testIgnoreCase("[quote]")
+			|| parser.testIgnoreCase("[quote=")
+			|| parser.testIgnoreCase("[/quote]")
+		;
+	}
+
+	private String parseBlock() {
+		if( parser.currentChar() != '[' )
+			return null;
+		String s;
+		s = parseB();  if(s!=null) return s;
+		s = parseI();  if(s!=null) return s;
+		s = parseU();  if(s!=null) return s;
+		s = parseUrl1();  if(s!=null) return s;
+		s = parseUrl2();  if(s!=null) return s;
+		s = parseCode();  if(s!=null) return s;
+		s = parseImg();  if(s!=null) return s;
+		s = parseColor();  if(s!=null) return s;
+		s = parseSize();  if(s!=null) return s;
+		s = parseYouTube();  if(s!=null) return s;
+		s = parseQuote1();  if(s!=null) return s;
+		s = parseQuote2();  if(s!=null) return s;
+		return null;
+	}
+
+	private String parseB() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[b]") )
+			return parser.failure(null);
+		String content = parseWellFormed();
+		if( !parser.matchIgnoreCase("[/b]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<b>"+content+"</b>" : content;
+		return parser.success(rtn);
+	}
+
+	private String parseI() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[i]") )
+			return parser.failure(null);
+		String content = parseWellFormed();
+		if( !parser.matchIgnoreCase("[/i]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<i>"+content+"</i>" : content;
+		return parser.success(rtn);
+	}
+
+	private String parseU() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[u]") )
+			return parser.failure(null);
+		String content = parseWellFormed();
+		if( !parser.matchIgnoreCase("[/u]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<u>"+content+"</u>" : content;
+		return parser.success(rtn);
+	}
+
+	private String parseUrl1() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[url]") )
+			return parser.failure(null);
+		String url = parseRealUrl();
+		if( !parser.matchIgnoreCase("[/url]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<a href='"+url+"'>"+url+"</a>" : url;
+		return parser.success(rtn);
+	}
+
+	private String parseUrl2() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[url=") )
+			return parser.failure(null);
+		String url = parseRealUrl();
+		if( !parser.match(']') )
+			return parser.failure(null);
+		String content = parseWellFormed();
+		if( !parser.matchIgnoreCase("[/url]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<a href='"+url+"'>"+content+"</a>" : content;
+		return parser.success(rtn);
+	}
+
+	private String parseRealUrl() {
+		parser.begin();
+		while( parser.match(' ') );
+		int start = parser.currentIndex();
+		if( !parser.matchIgnoreCase("http") )
+			return parser.failure(null);
+		parser.matchIgnoreCase("s");
+		if( !parser.matchIgnoreCase("://") )
+			return parser.failure(null);
+		while( parser.noneOf(" []'") );
+		String url = parser.textFrom(start);
+		while( parser.match(' ') );
+		return parser.success(url);
+	}
+
+	private String parseCode() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[code]") )
+			return parser.failure(null);
+		int start = parser.currentIndex();
+		while( !parser.testIgnoreCase("[/code]") ) {
+			if( !parser.anyChar() )
+				return parser.failure(null);
+		}
+		String content = parser.textFrom(start);
+		if( !parser.matchIgnoreCase("[/code]") ) throw new RuntimeException();
+		String rtn = target==Target.HTML ? "<code>"+content+"</code>" : content;
+		return parser.success(rtn);
+	}
+
+	private String parseImg() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[img]") )
+			return parser.failure(null);
+		String url = parseRealUrl();
+		if( !parser.matchIgnoreCase("[/img]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<img src='"+url+"'>" : "";
+		return parser.success(rtn);
+	}
+
+	private String parseColor() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[color=") )
+			return parser.failure(null);
+		int start = parser.currentIndex();
+		parser.match('#');
+		while( parser.inCharRange('0','9')
+			|| parser.inCharRange('a','z')
+			|| parser.inCharRange('A','Z')
+		);
+		String color = parser.textFrom(start);
+		if( !parser.match(']') )
+			return parser.failure(null);
+		String content = parseWellFormed();
+		if( !parser.matchIgnoreCase("[/color]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<span style='color: "+color+"'>"+content+"</span>" : content;
+		return parser.success(rtn);
+	}
+
+	private String parseSize() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[size=") )
+			return parser.failure(null);
+		int start = parser.currentIndex();
+		while( parser.match('.') || parser.inCharRange('0','9') );
+		String size = parser.textFrom(start);
+		if( !parser.match(']') )
+			return parser.failure(null);
+		String content = parseWellFormed();
+		if( !parser.matchIgnoreCase("[/size]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<span style='font-size: "+size+"em'>"+content+"</span>" : content;
+		return parser.success(rtn);
+	}
+
+	private String parseYouTube() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[youtube]") )
+			return parser.failure(null);
+		int start = parser.currentIndex();
+		while( parser.inCharRange('0','9')
+			|| parser.inCharRange('a','z')
+			|| parser.inCharRange('A','Z')
+			|| parser.match('-')
+			|| parser.match('_')
+		);
+		String id = parser.textFrom(start);
+		if( id.length()==0 || !parser.matchIgnoreCase("[/youtube]") )
+			return parser.failure(null);
+		String rtn = target==Target.HTML ? "<iframe width='420' height='315' src='https://www.youtube.com/embed/"+id+"' frameborder='0' allowfullscreen></iframe>" : "";
+		return parser.success(rtn);
+	}
+
+	private String parseQuote1() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[quote]") )
+			return parser.failure(null);
+		String content = parseWellFormed();
+		if( !parser.matchIgnoreCase("[/quote]") )
+			return parser.failure(null);
+		String rtn = quoter.quote(target,content,null);
+		return parser.success(rtn);
+	}
+
+	private String parseQuote2() {
+		parser.begin();
+		if( !parser.matchIgnoreCase("[quote=") )
+			return parser.failure(null);
+		List args = new ArrayList();
+		int start = parser.currentIndex();
+		while( parser.noneOf("[]") );
+		String name = parser.textFrom(start).trim();
+		if( !parser.match(']') )
+			return parser.failure(null);
+		String content = parseWellFormed();
+		if( !parser.matchIgnoreCase("[/quote]") )
+			return parser.failure(null);
+		String rtn = quoter.quote(target,content,name);
+		return parser.success(rtn);
+	}
+
+	public static String htmlEncode(String s) {
+		final char[] a = s.toCharArray();
+		StringBuilder buf = new StringBuilder();
+		for( char c : a ) {
+			switch(c) {
+			case '&':
+				buf.append("&amp;");
+				break;
+			case '<':
+				buf.append("&lt;");
+				break;
+			case '>':
+				buf.append("&gt;");
+				break;
+			case '"':
+				buf.append("&quot;");
+				break;
+			default:
+				buf.append(c);
+			}
+		}
+		return buf.toString();
+	}
+
+}