Fix BufferOverflowException

[Liloveyang]

Hello developer, first of all, thank you for opening your code. We developed a tool to scan whether there is runtime exception in the source code of the project. Then we scanned your code and found a method that may need to add try catch module! It is the putto method of rembulan-runtime \src\main\java\net\sandius\rembulan\stringbytestring.java.

Error reason: there is not enough space for ByteBuffer to store byte array parsed by string. Here is my test code,I've fixed the code,Thank you for your reply.

import sun.nio.cs.UTF_32;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.Objects;

public class StringByteString {
private final String string;
private final Charset charset;

private int byteHashCode;
private int byteLength;

StringByteString(String s, Charset charset) {
    this.string = Objects.requireNonNull(s);
    this.charset = Objects.requireNonNull(charset);
    if (!charset.canEncode()) {
        throw new IllegalArgumentException("Charset cannot encode: " + charset.name());
    }
    this.byteHashCode = 0;
    this.byteLength = string.isEmpty() ? 0 : -1;
}

private byte[] toBytes() {
    // TODO: cache the result
    return string.getBytes(charset);
}

public byte[] getBytes() {
    byte[] bytes = toBytes();

    // must make a defensive copy
    return Arrays.copyOf(bytes, bytes.length);
}

public void putTo(ByteBuffer buffer) {
    // ByteBuffer cannot be directly extended: it's safe to use a possibly cached array
    buffer.put(toBytes());
}

public static void main(String[] args) {
    StringByteString stringByteString = new StringByteString("I am Test",new UTF_32());
    ByteBuffer byteBuffer = ByteBuffer.allocate(2);
    stringByteString.putTo(byteBuffer);
}

}