PDU lib under STL for SMS

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Introduction

The SMS message, as specified by the Etsi organization (documents GSM 03.40 and GSM 03.38), can be up to 160 characters long, where each character is 7 bits according to the 7-bit default alphabet. Eight-bit messages (max 140 characters) are usually not viewable by the phones as text messages; instead, they are used for data in, e.g., smart messaging (images and ringing tones) and OTA provisioning of WAP settings. 16-bit messages (max 70 characters) are used for Unicode (UCS2) text messages, viewable by most phones. A 16-bit text message of class 0 will, on some phones, appear as a Flash SMS (a.k.a. blinking SMS or alert SMS).

Please see dreamfabric for details.

This lib is used to encode/decode plain text to PDU format under 7-bit or UCS2 (yes, the EMS is not supported yet). This lib is easy to use, but not bug free, so please be patient :).

I have searched the internet, and there are some great libs for the PDU format under the .NET Framework which I can't use in my current job, so I wrote this lib for my own needs.

Source code

The source code is very simple, only two files; you can add them to your project or build a lib.

How to use...

There are two main function for the lib: Compose() and Fetch(). Using these two functions, you can compose a message or fetch data form a PDU string.

/**
 *    Compose a shot message
 *    @para pdudata pdu: [out] The pdu result
 *    @para string msg:    data need to be sent
 *    @para string phone:    the destination phone number
 *    @para string msc:    message center number, if null, use the preset number
 *    @para EEncodeMethod eMethod:    the encode method, default is UCS2
 *
 *    @return the data length without the SMSC part[you need it in AT+CMGS command]
 */
int Compose (pdudata& pdu, 
    std::tstring msg, std::tstring phone,
    std::tstring msc = _T(""),
    EEncodeMethod eMethod = EEncodeUCS2) throw(...);


/**
 *    Fetch data form a pdu format data
 *    only return the message part(USERDATA), 
      use other member function to fetch information
 *    @para pdudata pdu: the source data
 *
 *    @return The nomral message
 */
std::tstring Fetch(pdudata pdu) throw(...);

Compose an SMS message

To compose a message, you need do this:

CPDU pdu;
LPCTSTR szMsg = m_szEncodeContents.GetBuffer(m_szEncodeContents.GetLength());
pdu.SetMSCNumber(_T("13800210500"));    // Set the message center number here
try {

    CPDU::pdudata strPDU;
    // Compose the message
    int iLen = pdu.Compose(strPDU, szMsg, _T("13813878775"));
    WTL::CString csPDU;

    
    // Show the message to the output edit control
#ifdef _UNICODE
    MultiByteToWideChar(
        CP_ACP, 
        MB_PRECOMPOSED, 
        strPDU.c_str(), 
        -1,
        csPDU.GetBuffer(1024),
        1024
        );
#else
    csPDU = strPDU.c_str();
#endif // _UNICODE

    m_szDecodeContents = csPDU;
} catch (CPDUException e) {
    m_szDecodeContents = e.GetMessage().c_str();
}

Fetch data

When you need to fetch a message, you need do this:

CPDU pdu;
WTL::CString szMessage = pdu.Fetch(pdustring);

If there are no exceptions, then you can use these functions to fetch other data:

/**
 *    Fetch Data
 */
// The caller/sender number
std::tstring GetCaller()        { return m_szCaller; }
// The callee/recevier number
std::tstring GetCallee()        { return m_szCallee; }
// Message time stamp
std::tstring GetTimeStamp()        { return m_szTimeStamp; }

Notice

The tstl.h file is a TCHAR style header file for STL strings and streams.

Update

• May 22 2007: Fixed a bug in the Decode7bit function, thanks to alexafros12345 :)