问题
I have written a program to decode a CDMA 3GPP2 point-to-point SMS message. I tested it on a couple CDMA PDU hex strings I found on the internet, and it works perfectly. However, when I try to implement it on all incoming text messages on the Android platform, it always fails.
I took a look at the incoming PDU, and it doesn't seem to follow the same pattern I have been used to seeing. Can anyone explain what format this PDU is in, or what I am missing to correctly decode this PDU? Is there additional header or fields I am not taking into account?
Example PDU pulled from a incoming text message on my phone:
000000000000100200000000000000000A36373839313031363734000000000000000000001B000310864D000306120624205611010B104C2CF9F3F5EBD73E7000
All of the CDMA pdus I found and tested my parser on look more like:
00000210020207028CE95DCC65800601FC08150003168D3001061024183060800306101004044847
Carrier: Verizon
Phone: Samsung Galaxy S Fascinate
running Android 2.3.3
回答1:
See the javadoc from $SDK/sources/android-16/com/android/internal/telephony/cdma/SmsMessage:
/**
* Creates byte array (pseudo pdu) from SMS object.
* Note: Do not call this method more than once per object!
*/
...so it's not following any particular CDMA standard. You can decode it however; so in fine ASCII art:-
000000000000100200000000000000000A36373839313031363734000000000000000000001B000310864D000306120624205611010B104C2CF9F3F5EBD73E7000
--------messageType --digitMode --------bearerReply ------------------------------------------------------bearer data
--------teleService --ton --------------------src --replySeqNo --messageID --msts --userdata
--------serviceCategory --errorClass --len --XX--len --len
--numberMode --causeCode ------ ------------2012/06/24 20:56:11
--npi --------bearerDataLength ----------------------userdata
--len
Note that I think you made a cut/paste error in your message - the 00 byte marked 'XX' I think shouldn't be there - luckily it's easy to spot the date and work backwards. So this is a message from 6789101674 with userdata:
104C2CF9F3F5EBD73E7000, the first five bits of which show that it's 7-bit encoded (0x02). Having shifted the remainder of the userdata 5 bits to the left, we're left with:
09859f3e7ebd7ae7ce00
--len(septets) 9 septets == 63 bits, so we expect 8 bytes of body
----------------7bit-body
So your 7bit-body decoded is "Bggguuugg".
来源:https://stackoverflow.com/questions/11182650/cdma-pdu-parsing-on-android