how should I read data from file if size return is logical size of file

Hello All,
I want to get the size of the file. So I am using function

result = FSOpenFork(&ref, dataForkName.length, dataForkName.unicode, fsRdPerm, &forkRefNum);
result = FSGetForkSize(forkRefNum, &forkSize);
result = GetEOF(forkRefNum,&lfrksz);

both the functions returns filesize as 998 bytes but on disk file size shown is 4 KB that is 406 bytes.
forksize written is logical size , but how should I read the data from file. I am using. I could not understand that how should I treat the logical size, if data stored in file is serial bytes.
forkData =(void *)malloc(forkSize);
if (forkData != NULL)
{
Err1= FSReadFork(forkRefNum,fsFromStart,0, forkSize,&forkData, &actualCount);
}


if suppose f1.txt is
6790
8967
4035
etc.

 

Hello Shogododdo ,
Thanks for reply.
But what you are assuming is wrong.
physical size on disk of a file is 4 KB (406 bytes) and
logical size returned by result = FSGetForkSize(forkRefNum, &forkSize); is 998.

 

Hello Shogododdo ,
Thanks for reply.
I am extremely sorry.
You may laugh on me , because I was passing different file ref and looking at another path file for its size.

Sorry for this stupid question.
Now I am getting logical file size = physical size = 406 bytes.
And I am able read file data properly.