Decodes a BER-TLV object from a byte array.
int curIndex = 0;
int endIndex = data.length;
int tag, length = 0;
boolean isLengthValid = true;
try {
/* tag */
tag = data[curIndex++] & 0xff;
if (tag == BER_PROACTIVE_COMMAND_TAG) {
/* length */
int temp = data[curIndex++] & 0xff;
if (temp < 0x80) {
length = temp;
} else if (temp == 0x81) {
temp = data[curIndex++] & 0xff;
if (temp < 0x80) {
throw new ResultException(
ResultCode.CMD_DATA_NOT_UNDERSTOOD,
"length < 0x80 length=" + Integer.toHexString(length) +
" curIndex=" + curIndex + " endIndex=" + endIndex);
}
length = temp;
} else {
throw new ResultException(
ResultCode.CMD_DATA_NOT_UNDERSTOOD,
"Expected first byte to be length or a length tag and < 0x81" +
" byte= " + Integer.toHexString(temp) + " curIndex=" + curIndex +
" endIndex=" + endIndex);
}
} else {
if (ComprehensionTlvTag.COMMAND_DETAILS.value() == (tag & ~0x80)) {
tag = BER_UNKNOWN_TAG;
curIndex = 0;
}
}
} catch (IndexOutOfBoundsException e) {
throw new ResultException(ResultCode.REQUIRED_VALUES_MISSING,
"IndexOutOfBoundsException " +
" curIndex=" + curIndex + " endIndex=" + endIndex);
} catch (ResultException e) {
throw new ResultException(ResultCode.CMD_DATA_NOT_UNDERSTOOD, e.explanation());
}
/* COMPREHENSION-TLVs */
if (endIndex - curIndex < length) {
throw new ResultException(ResultCode.CMD_DATA_NOT_UNDERSTOOD,
"Command had extra data endIndex=" + endIndex + " curIndex=" + curIndex +
" length=" + length);
}
List<ComprehensionTlv> ctlvs = ComprehensionTlv.decodeMany(data,
curIndex);
if (tag == BER_PROACTIVE_COMMAND_TAG) {
int totalLength = 0;
for (ComprehensionTlv item : ctlvs) {
int itemLength = item.getLength();
if (itemLength >= 0x80 && itemLength <= 0xFF) {
totalLength += itemLength + 3; //3: 'tag'(1 byte) and 'length'(2 bytes).
} else if (itemLength >= 0 && itemLength < 0x80) {
totalLength += itemLength + 2; //2: 'tag'(1 byte) and 'length'(1 byte).
} else {
isLengthValid = false;
break;
}
}
// According to 3gpp11.14, chapter 6.10.6 "Length errors",
// If the total lengths of the SIMPLE-TLV data objects are not
// consistent with the length given in the BER-TLV data object,
// then the whole BER-TLV data object shall be rejected. The
// result field in the TERMINAL RESPONSE shall have the error
// condition "Command data not understood by ME".
if (length != totalLength) {
isLengthValid = false;
}
}
return new BerTlv(tag, ctlvs, isLengthValid);
