Implement writeUTF

src/main/java/it/cavallium/dbengine/buffers/BufDataOutput.java

@@ -1,5 +1,8 @@
 package it.cavallium.dbengine.buffers;
 
+import static org.warp.commonutils.stream.SafeDataOutputStream.strLen;
+import static org.warp.commonutils.stream.SafeDataOutputStream.utfLen;
+
 import it.unimi.dsi.fastutil.Arrays;
 import java.io.DataOutput;
 import java.io.IOException;
@@ -178,9 +181,23 @@ public class BufDataOutput implements DataOutput {
 		dOut.writeChars(s);
 	}
 
+	private static String tooLongMsg(String s, int bits32) {
+		int slen = s.length();
+		String head = s.substring(0, 8);
+		String tail = s.substring(slen - 8, slen);
+		// handle int overflow with max 3x expansion
+		long actualLength = (long)slen + Integer.toUnsignedLong(bits32 - slen);
+		return "encoded string (" + head + "..." + tail + ") too long: "
+				+ actualLength + " bytes";
+	}
+
 	@Override
-	public void writeUTF(@NotNull String s) {
+	public void writeUTF(@NotNull String str) {
-		throw new UnsupportedOperationException();
+		var strlen = strLen(str);
+		var utflen = utfLen(str, strlen);
+		var bytes = Short.BYTES + utflen;
+		checkOutOfBounds(bytes);
+		dOut.writeUTF(strlen, utflen, str);
 	}
 
 	public Buf asList() {

src/main/java/org/warp/commonutils/stream/SafeDataOutputStream.java

@@ -310,6 +310,10 @@ public class SafeDataOutputStream extends SafeFilterOutputStream implements Safe
 		writeUTF(str, this);
 	}
 
+	public final void writeUTF(int strlen, int utflen, String str) {
+		writeUTF(strlen, utflen, str, this);
+	}
+
 	/**
 	 * Writes a string to the specified DataOutput using
 	 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
@@ -330,18 +334,30 @@ public class SafeDataOutputStream extends SafeFilterOutputStream implements Safe
 	 * @return     The number of bytes written out.
 	 */
 	static int writeUTF(String str, SafeDataOutput out) {
-		final int strlen = str.length();
+		int strlen = strLen(str);
-		int utflen = strlen; // optimized for ASCII
+		int utflen = utfLen(str, strlen);
+		return writeUTF(strlen, utflen, str, out);
+	}
 
-		for (int i = 0; i < strlen; i++) {
+	public static int strLen(String str) {
+		return str.length();
+	}
+
+	public static int utfLen(String str, int strLen) {
+		int utflen = strLen; // optimized for ASCII
+
+		for (int i = 0; i < strLen; i++) {
 			int c = str.charAt(i);
 			if (c >= 0x80 || c == 0)
 				utflen += (c >= 0x800) ? 2 : 1;
 		}
 
-		if (utflen > 65535 || /* overflow */ utflen < strlen)
+		if (utflen > 65535 || /* overflow */ utflen < strLen)
 			throw new IllegalArgumentException(tooLongMsg(str, utflen));
+		return utflen;
+	}
 
+	static int writeUTF(int strlen, int utflen, String str, SafeDataOutput out) {
 		final byte[] bytearr;
 		if (out instanceof SafeDataOutputStream) {
 			SafeDataOutputStream dos = (SafeDataOutputStream)out;