package com.cloudhopper.smpp.util;
/*
* #%L
* ch-smpp
* %%
* Copyright (C) 2009 - 2012 Cloudhopper by Twitter
* %%
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* #L%
*/
import com.cloudhopper.smpp.tlv.Tlv;
import com.cloudhopper.smpp.tlv.TlvConvertException;
import java.io.UnsupportedEncodingException;
/**
* Utility class for working with TLVs.
*
* @author joelauer (twitter: @jjlauer or <a href="http://twitter.com/jjlauer" target=window>http://twitter.com/jjlauer</a>)
*/
public class TlvUtil {
/**
* Writes a variable length C-String (null terminated) TLV. If the String
* is null this method will only write out the NULL byte (0x00) TLV. Uses
* ISO-8859-1 as the charset to convert the String into bytes.
* @param tag The TLV tag value
* @param value The String to include in the TLV value
* @return A new TLV
* @throws TlvConvertException Thrown if there is an error during conversion
* of the value into TLV.
*/
static public Tlv createNullTerminatedStringTlv(short tag, String value) throws TlvConvertException {
return createNullTerminatedStringTlv(tag, value, "ISO-8859-1");
}
/**
* Writes a variable length C-String (null terminated) TLV. If the String
* is null this method will only write out the NULL byte (0x00) TLV.
* @param tag The TLV tag value
* @param value The String to include in the TLV value
* @param charsetName The charsetName to use to convert the String into bytes
* @return A new TLV
* @throws TlvConvertException Thrown if there is an error during conversion
* of the value into TLV.
*/
static public Tlv createNullTerminatedStringTlv(short tag, String value, String charsetName) throws TlvConvertException {
try {
if (value == null) {
value = "";
}
// convert the string into a byte array
byte[] bytes = value.getBytes(charsetName);
// create a new byte array with a null byte
byte[] bytes0 = new byte[bytes.length+1];
System.arraycopy(bytes, 0, bytes0, 0, bytes.length);
return new Tlv(tag, bytes0);
} catch (UnsupportedEncodingException e) {
throw new TlvConvertException("String", "unsupported charset " + e.getMessage());
}
}
/**
* Writes a fixed length String TLV with null bytes filling the remaining
* part of the byte array. For example, if "1" is the String and the fixed
* length is 4, then the internal value of the TLV would be "31000000".
* @param tag The TLV tag value
* @param value The String to include in the TLV value
* @param fixedLength The fixed length of the byte array value of the TLV
* @return A new TLV
* @throws TlvConvertException Thrown if there is an error during conversion
* of the value into TLV.
*/
static public Tlv createFixedLengthStringTlv(short tag, String value, int fixedLength) throws TlvConvertException {
return createFixedLengthStringTlv(tag, value, fixedLength, "ISO-8859-1");
}
/**
* Writes a fixed length String TLV with null bytes filling the remaining
* part of the byte array. For example, if "1" is the String and the fixed
* length is 4, then the internal value of the TLV would be "31000000".
* @param tag The TLV tag value
* @param value The String to include in the TLV value
* @param fixedLength The fixed length of the byte array value of the TLV
* @param charsetName The charsetName to use to convert the String into bytes
* @return A new TLV
* @throws TlvConvertException Thrown if there is an error during conversion
* of the value into TLV.
*/
static public Tlv createFixedLengthStringTlv(short tag, String value, int fixedLength, String charsetName) throws TlvConvertException {
try {
if (value == null) {
value = "";
}
// convert the string into a byte array
byte[] bytes = value.getBytes(charsetName);
// is this string longer than the fixed length?
if (bytes.length > fixedLength) {
throw new TlvConvertException("String", "length exceeds fixed length ["+fixedLength+"]");
}
// do we need to pad the string?
if (bytes.length < fixedLength) {
// create a new byte array with a null byte
byte[] bytes0 = new byte[fixedLength];
System.arraycopy(bytes, 0, bytes0, 0, bytes.length);
bytes = bytes0; // use the new array
}
return new Tlv(tag, bytes);
} catch (UnsupportedEncodingException e) {
throw new TlvConvertException("String", "unsupported charset " + e.getMessage());
}
}
}