writeAscii_slow should be able to write at least one byte into the ou…

…tput buffer.

Fixes #503

src/com/esotericsoftware/kryo/io/Output.java

@@ -482,8 +482,14 @@ private void writeString_slow (CharSequence value, int charCount, int charIndex)
 	}
 
 	private void writeAscii_slow (String value, int charCount) throws KryoException {
-		byte[] buffer = this.buffer;
+		if (charCount == 0)
+			return;
+		// It should be possible to write at least one character.
+		if (capacity == 0) {
+			require(1);
+		}
 		int charIndex = 0;
+		byte[] buffer = this.buffer;
 		int charsToWrite = Math.min(charCount, capacity - position);
 		while (charIndex < charCount) {
 			value.getBytes(charIndex, charIndex + charsToWrite, buffer, position);

test/com/esotericsoftware/kryo/KryoStringTest.java

@@ -0,0 +1,58 @@
+/* Copyright (c) 2008, Nathan Sweet
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
+ * conditions are met:
+ * 
+ * - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided with the distribution.
+ * - Neither the name of Esoteric Software nor the names of its contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
+
+package com.esotericsoftware.kryo;
+
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+import org.junit.Test;
+
+import com.esotericsoftware.kryo.FieldSerializerTest.DefaultTypes;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+import com.esotericsoftware.kryo.pool.KryoFactory;
+import com.esotericsoftware.kryo.pool.KryoPool;
+import com.esotericsoftware.kryo.serializers.MapSerializer;
+
+public class KryoStringTest extends KryoTestCase {
+
+	static KryoFactory factory = new KryoFactory() {
+		@Override
+		public Kryo create () {
+			Kryo kryo = new Kryo();
+			return kryo;
+		}
+	};
+
+	public void testSerialize () {
+		String reason = "node/read";
+		long localTimestamp = 1;
+		KryoPool pool = new KryoPool.Builder(factory).softReferences().build();
+		Kryo kryo = pool.borrow();
+
+		// Allocate an output buffer with initial size of 0.
+		final Output output = new Output(0, 10024);
+		// Check that it is possible to write an ASCII string into the output buffer.
+		output.writeString(reason);
+	}
+}