Comprehensive analysis of Java pdu short message decoding

Long SMS not verified, those interested can try it

Rewritten based on the Python method

/**
* PDU SMS parsing
*
*
* @param pduPayload
* @return
*/
public static String retrieveSMSInfo(byte[] pduPayload) throws UnsupportedEncodingException {
int startPos = 3;
//#Originator address
int mRP_OA_len = pduPayload[startPos];
byte[] mRP_OA = new byte[mRP_OA_len];
System.arraycopy(pduPayload, startPos + 1, mRP_OA, 0, mRP_OA_len);
startPos = startPos + 1 + mRP_OA_len;
int mTPDU_len = pduPayload[startPos];
//#BIT No. 7 6 5 4 3 2 1 0 
//#uplink TP-RP TP-UDHI TP-SPR TP-VPF TP-RD TP-MTI 
//#downlink TP-RP TP-UDHI TP-SRI TP-MMS TP-MTI 
byte TP_Header = pduPayload[startPos + 1];
byte TP_Msg_Ref = pduPayload[startPos + 2];
int TP_UDHI = (TP_Header >> 6) & 1; //# Whether the SMS content includes protocol header information, 0 does not include, 1 Include (long SMS, push SMS)
int TP_VPF = (TP_Header >> 3) & 3; //# Whether to include the validity period byte, 0 does not include, others include 
// #00 indicates no validity period, TP-VP set to 00. 
// #10indicates relative format, TP-VP usage1byte. 
// #01indicates incremented format, TP-VP usage7byte. 
// #11indicates absolute format, TP-VP usage7Byte
int TP_MMS = (TP_Header >> 2) & 1;//# TP-MMS(TP-More-Message-to-Send):1 The SMS Center has no more messages to send
startPos = startPos + 3;
//# Opposite Number
byte smsNumberLen = pduPayload[startPos];
int mTP_DA_len = (smsNumberLen + 1)}} / 2 + 1;
byte[] mTP_DA = new byte[mTP_DA_len];
System.arraycopy(pduPayload, startPos + 1, mTP_DA, 0, mTP_DA_len * 1);
byte mTP_DA_format = mTP_DA[0];
byte[] smsNumberRaw = new byte[mTP_DA.length - 1];
System.arraycopy(mTP_DA, 1, smsNumberRaw, 0, mTP_DA.length - 1);
String smsNumber = "";
int j = 0;
for (int i = 0; i < smsNumberLen; i++) {
if ((i & 1) == 0) {
smsNumber = smsNumber + (int) (smsNumberRaw[j] & 0xF);
} else {
smsNumber = smsNumber + (int) ((smsNumberRaw[j] & 0x0FF) >> 4);
j++;
}
}
startPos = startPos + 1 + mTP_DA_len;
byte mTP_PID = pduPayload[startPos];
byte mTP_DCS = pduPayload[startPos] + 1];//#“00”表示使用7位编码，设置为“02”使用8位编码，设置为“08”使用UCS2编码。
startPos = startPos + 2;
if (TP_VPF == 2) {
startPos = startPos + 1;
} else if (TP_VPF == 1 || TP_VPF == 3) {
startPos = startPos + 7;
}
//# 长短信：内容前面需要增加6个字段 
//# 1、 字节一：包头长度，固定填写0x05； 
//# 2、 字节二：包头类型标识，固定填写0x00，表示长短信； 
//# 3、 字节三：子包长度，固定填写0x03，表示后面三个字节的长度； 
//# 4、 字节四到字节六：包内容： 
//# a） 字节四：长消息参考号，每个SP给每个用户发送的每条参考号都应该不同，可以从0开始，每次加1，最大255，便于同一个终端对同一个SP的消息的不同的长短信进行识别； 
//# b） 字节五：本条长消息的的总消息数，从1到255，一般取值应该大于2； 
//# c） 字节六：本条消息在长消息中的位置或序号，从1到255，第一条为1，第二条为2，最后一条等于第四字节的值。 
//# 例子： 
//# 05 00 03 00 02 01 
//# 05 00 03 00 02 02 
int smsPayloadLen = pduPayload[startPos];
startPos = startPos + 1;
String smsContent = "";
if (TP_UDHI == 1) {
//#长短信--未验证 可能需要转无符号
byte smsTotal = pduPayload[startPos + 4];
byte smsIdx = pduPayload[startPos + 5];
startPos = startPos + 6;
smsContent = "长短信(" + byteToHex(smsIdx) + ""/"" + byteToHex(smsTotal) + "}";
smsContent = new String(smsContent.getBytes("gbk"));
smsPayloadLen = smsPayloadLen - 6;
}
byte[] smsPayload = new byte[pduPayload.length - startPos];
System.arraycopy(pduPayload, startPos, smsPayload, 0, pduPayload.length - startPos);
if (mTP_DCS == 0) {
//#7位编码--已验证
smsPayloadLen = (smsPayloadLen * 7 + 7)}} / 8;
int asciiData = 0;
int lastByteRemain = 0;
for (int i = 0; i < smsPayloadLen; i++) {
asciiData = asciiData + ((smsPayload[i] & 0x0FF) << lastByteRemain);
smsContent = smsContent + (char) ((asciiData & 0x0FF) & 0x7f);
asciiData = asciiData >> 7;
lastByteRemain = lastByteRemain + 1;
if (lastByteRemain >= 7) {
smsContent = smsContent + (char) ((asciiData & 0x0FF) & 0x7f);
asciiData = asciiData >> 7;
lastByteRemain = lastByteRemain - 7;
}
}
} else if (mTP_DCS == 8) {
//# UCS-2 --Verified, can be parsed normally
for (int i = 0; i < smsPayloadLen; i = i + 2) {
int cc1 = (smsPayload[i] & 0x0FF) * 256;
int cc2 = smsPayload[i + 1] & 0x0FF;
smsContent = smsContent + (char) (cc1 + cc2);
}
}
return smsNumber + " + smsContent;
}

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