Integers treated as signed 16-bit values in Serializer

[thielema]

I hit a limit of 32768 objects in a large generated PDF. With 32768 objects or more the /Size entry in the trailer becomes negative.
The culprit is Serializer.cshortToString.
First, the foreign import is wrong because it pretends the number parameter would be Int, where in reality the corresponding C type is short, thus the Haskell foreign import must use CShort. But this happens to work by accident on my machine (little endian).
Second, the bigger problem is the choice of the short type. This is 16 bit on my machine. Why this restriction? Why call C functions at all? Are they significantly faster than the Haskell formatting functions?

[thielema]

There is also a problem with convertFloat. It assumes at most 12 characters (minus one terminating null byte) in the formatted string. This can easily be exceeded using a sufficiently large Float number. However, the Haskell code must assume any maximum number of characters for allocating a buffer for the formatted number.
I think the best is to get rid of the C code completely.

[hsyl20]

It looks reasonable to get rid of C code. Could you update the PR? Thanks!

[thielema]

Removed C code. Checked that demo.pdf stays the same.

[hsyl20]

Thanks! It's merged and released https://hackage.haskell.org/package/HPDF-1.6.2