Dynamic cast
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Hi,
I am new to QT. Was trying an option in a tool which receives a set of variables and a file that has info about their data types. If i need to store and display them, which is the best way to dynamically cast.
For example:
If i receive 4 bytes which has 3 variables A(qint16) B(quint8) C(qint8)
say i define a qint64 val;
val = (dynamic casting) A/B/C ;
Is there a better way other than check the data type and use switch-case to cast it i.e
if (data_type == "quint16") { val = (quint16)data; } etc... -
From "this doc":http://www.cplusplus.com/doc/tutorial/typecasting/#dynamic_cast
"dynamic_cast can only be used with pointers and references to classes (or with void*)."So dynamic_cats will not work for the integers.
If you need to convert a bunch of bytes into integer then you need to know what kind of integer you will use. Which makes it impossible to avoid some kind of if/else or switch statement. You can hide it but I don't any other way to convert the bytes to the integer.Or I'm totally misunderstood your question :-)
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Instead of dynamic_cast you can use the old school solution: a union
for example:
@union
{
qint32 v32;
struct
{
qint16 v16A;
qint16 v16B;
} v16;
struct
{
qint8 V8A;
qint8 V8B;
qint8 V8C;
qint8 V8D;
} v8;
} receivedblob; @So for example:
receivedblob.v32 = received4bytes();receivedblob.v16.v16a will now read the same bits as receivedblob.v8.V8A and V8B, and of course receivedblob.v32 lower half :-)
