fgets array size

How big is too big?

I wrote a program for school that does Huffman compression. I use fgets to get my encoded string for decoding. Right now the encoded file is stored as one continous string (no newline). So I have been having to use numbers like 100,000 in the fgets call just to decode average size files.

fgets(array pointer, 100,000, infile);

Is there a better way to do this?

Are you sure you're using the right routine?

It seems to me that if the data is a Huffman compression stream, that it would be binary data.

In which case, you should be using fread, not fgets

I actually am supposed to not use binary data for this. The TA told me it is easier for him to check that way. To get the actually compression ratio you have to divide by eight. This is another reason for the large sized array.

Well there's no need to read the whole lot in one array, fgets will read in a loop like so.

Code:

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char buff[1000];
while ( fgets( buff, 1000, infile ) != NULL ) {
  // reads the file in 999 byte blocks
}

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Thanks, that is exactly what I was asking. To make sure I understand, fgets will return to the next positon from where the filepointer stopped last time. Is this correct?

One more related ques, what is the max number for an array size? I guess it will vary from machine to machine. But what is a ballpark figure?

Your TA is a blockhead! Use fread and then you'll be able to even keep yer newlines in the file....

I won't disagree on that...

I am actually considering doing that, but I am going to talk to my prof first. I am sure he won't care.

Quote:

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Originally posted by Sebastiani
Your TA is a blockhead! Use fread and then you'll be able to even keep yer newlines in the file....

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I'm not too up on Huffman, but at a guess I'd say the encoded data could well contain non-printable characters, including those nasty 0x00's.

If that's the case, when you use fgets (which is used to get a string, and automatically terminate it with a 0x00), won't you get confused between 0x00's in the data, and those added by fgets?

If you use fread, that will read anything into the array, and return the number of items read. Data integrity is maintained.

There, that's my thoughts anyways......

> One more related ques, what is the max number for an array size?
Depends on your compiler / OS
Real DOS is limited to 64K
Pretty much everything else is measured in MBytes

For reading text files, the BUFSIZ macro in stdio.h is a good bet

> but at a guess I'd say the encoded data could well contain non-printable characters
It was my impression that the binary data has been 'ascii-fied' - like uuencode or MIME, only different.