add binary test case

doc/parsing-binary-files.md

@@ -0,0 +1,94 @@
+# Parsing Binary Files
+
+```
+grammar IP;
+
+file : ip+ (MARKER ip)* ;
+
+ip : BYTE BYTE BYTE BYTE ;
+
+MARKER : '\u00CA' '\u00FE' ;
+BYTE : '\u0000'..'\u00FF' ;
+```
+
+```java
+package binary;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.file.Files;
+
+public class WriteBinaryFile {
+	public static final byte[] bytes = {
+		(byte)172, 0, 0, 1, (byte)0xCA, (byte)0xFE,
+		(byte)10, 10, 10, 1, (byte)0xCA, (byte)0xFE,
+		(byte)10, 10, 10, 99
+	};
+
+	public static void main(String[] args) throws IOException {
+		Files.write(new File("resources/ips").toPath(), bytes);
+	}
+}
+```
+
+```java
+package binary;
+
+import org.antlr.v4.runtime.ANTLRFileStream;
+import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.tree.ParseTree;
+import org.antlr.v4.runtime.tree.ParseTreeWalker;
+
+/** Test ANTLR parser that reads binary files full of IP addresses with
+ *  a 0xCAFE marker in between. Output should be:
+ [172, 0, 0, 1]
+ [10, 10, 10, 1]
+ [10, 10, 10, 99]
+ */
+public class TestBinary {
+	public static void main(String[] args) throws Exception {
+		ANTLRFileStream bytesAsChar = new BinaryANTLRFileStream("resources/ips");
+		IPLexer lexer = new IPLexer(bytesAsChar);
+		CommonTokenStream tokens = new CommonTokenStream(lexer);
+		tokens.fill();
+		IPParser parser = new IPParser(tokens);
+		ParseTree tree = parser.file();
+		IPBaseListener listener = new MyIPListener();
+		ParseTreeWalker.DEFAULT.walk(listener, tree);
+	}
+}
+```
+
+```
+package binary;
+
+import org.antlr.v4.runtime.ANTLRFileStream;
+import org.antlr.v4.runtime.misc.Interval;
+
+import java.io.IOException;
+
+/** make a stream treating file as full of single unsigned byte characters */
+class BinaryANTLRFileStream extends ANTLRFileStream {
+	public BinaryANTLRFileStream(String fileName) throws IOException {
+		super(fileName, "ISO-8859-1");
+	}
+
+	/** Print the decimal value rather than treat as char */
+	@Override
+	public String getText(Interval interval) {
+		StringBuilder buf = new StringBuilder();
+		int start = interval.a;
+		int stop = interval.b;
+		if(stop >= this.n) {
+			stop = this.n - 1;
+		}
+
+		for (int i = start; i<=stop; i++) {
+			int v = data[i];
+			buf.append(v);
+		}
+		return buf.toString();
+	}
+}
+```