symbian基本数据类型转化汇集（一）

每次碰都数据类型转换都头大，在网上乱搜一通才能搞定，特把搜到的有关基本数据类型转化的做个集合，以方便以后查找。

 

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转：http://blog.csdn.net/9527/archive/2006/08/29/1137637.aspx

 

1.串转换成数字
   TBuf16<20> buf(_L( "123" ) );
    TLex lex( buf );
    TInt iNum;
    lex.Val( iNum );
2.数字转换成串
   TBuf16<20> buf;
   TInt iNum = 20;
   buf.Format( _L( "%d" ) , iNum  );
3.将symbian串转换成char串
    char* p = NULL;
    TBuf8<20> buf( _L( "aaaaa" ) );
    p = (char *)buf.Ptr();

4.UTF-8转换成UNICODE
    CnvUtfConverter::ConvertToUnicodeFromUtf8( iBuf16 , iBuf8 );
5.UNICODE转换成UTF-8
    CnvUtfConverter::ConvertFromUnicodeToUtf8( iBuf8 , iBuf16 );

6.将char串转换成symbian串
    char* cc = "aaaa";
    TPtrC8 a;
    a.Set( (const TUint8*)cc , strlen(cc) );

再加一点：
TDesC8 & buf ;
TUint8   * pdata ;
pdata = buf.Ptr() ;
然后，这个pdata就可以当成unsigned char *用了，这在网络通讯的时候很重要。
如果，怕pdata破坏的话，可以
TBuf8<1024> tmp_buf ;
tmp_buf.Copy(buf) ;
pdata = tmp_buf.Ptr() ;
这样就可以保护一下buf的数据了，尤其是如果这个buf是Socket的接收的数据是接收函数自己分配的时候。

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http://wiki.forum.nokia.com/index.php/How_to_Convert_TBuf_to_Char_and_Vice_Versa

How to Convert TBuf to Char and Vice Versa

From Forum Nokia Wiki

void stringToDescriptor(const char* aString, TDes& aDescriptor){    TPtrC8 ptr(reinterpret_cast<const TUint8*>(aString));    aDescriptor.Copy(ptr);}

Usage:

const char* str = "Hello, world!";    TBuf<32> buffer;  // Make it large enough for str    stringToDescriptor(str, buffer);

Problem with the code above is that defining a TBuf not large enough will raise a USER 23 panic.

Some ways to avoid this include:

Using either __ASSERT_DEBUG or __ASSERT_ALWAYS, depending on your needs. Note that you can use alternatives to User::Panic(), as long as you avoid executing sensitive code.

void stringToDescriptor(const char* aString, TDes& aDescriptor){    TPtrC8 ptr(reinterpret_cast<const TUint8*>(aString));    _LIT(KMyPanicDescriptor, "My panic text");    __ASSERT_ALWAYS(User::StringLength(reinterpret_cast<const TUint8*>(aString)) <= aDescriptor.MaxLength(), User::Panic(KMyPanicDescriptor, 0));    aDescriptor.Copy(ptr);}

The other way is relying on a dynamic buffer, using HBufC for instance:

HBufC* stringToDescriptorL(const char* aString){    TPtrC8 ptr(reinterpret_cast<const TUint8*>(aString));    HBufC* buffer = HBufC::NewL(ptr.Length());    buffer->Des().Copy(ptr);     return buffer;}

Note that the caller is responsible of freeing the HBufC returned. Also note the trailing "L" in the function's name.

Depending on your code, you may prefere one of these over the others. Also, you may need to add extra checks (for instance, checking whether the char pointer is null or not).

Converting descriptors to C-strings may be done this way:

const char* descriptorToStringL(const TDesC& aDescriptor){    TInt length = aDescriptor.Length();     HBufC8* buffer = HBufC8::NewLC(length);    buffer->Des().Copy(aDescriptor);     char* str = new(ELeave) char[length + 1];    Mem::Copy(str, buffer->Ptr(), length);    str[length] = '/0';     CleanupStack::PopAndDestroy(buffer);     return str;}

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