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QUESTION:
I have the address of a string. How I can determine the size of the data starting at that address?
ANSWER:
Let's assume that the string is terminated by a zero byte (Ascii(0)). You can find out the size of the string by testing for the first zero byte in it by doing the following:
Function SizeOfData Address aData Returns Integer
Integer iPos
Repeat
Increment iPos
Until (DeRefC (aData, iPos) = 0)
Function_Return iPos
End_Function // SizeOfData
Example of the usage:
Get XSLTransformationToAddress Of hoXMLRoot hoXSLSource To aResult
If (aResult > 0) Begin
Get SizeOfData aResult To iDataSize
If the information is not in a DataFlex string and you want to copy that information from the pointer (address) to a DataFlex variable, you can make use of the following function (taken from cMapiHandler class) that copies the information to a DataFlex string:
Function CopyPointerToDfString Pointer lpsDataPointer Returns String
String sResult sCharacter
Integer iVoid
Pointer pCharacter
If (lpsDataPointer <> 0) Begin
ZeroString 1 To sCharacter
GetAddress Of sCharacter To pCharacter
Move (CopyMemory (pCharacter, lpsDataPointer, 1)) To iVoid
While (Ascii (sCharacter) <> 0)
Move (sResult + sCharacter) To sResult
Increment lpsDataPointer
Move (CopyMemory (pCharacter, lpsDataPointer, 1)) To iVoid
End
End
Function_Return sResult
End_Function // CopyPointerToDfString
The above is copying the information byte-by-byte.
NOTES:
1) The default maximum size of a local DataFlex string is 64KB (since VDF7) and the command SET_ARGUMENT_SIZE can be used to change this.
2) The above CopyPointerToDfString will therefore - if the argument size is not changed - only copy the first 65535 bytes.
Contributed By:
Vincent Oorsprong
Company: Data Access Worldwide
email: vincent.oorsprong@dataaccess.eu
Web Site: http://www.dataaccess.eu
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