[pdf-devel] CCITT filter and pdf_stm_filter_apply pdf_stm_filter_get_input function and cache size in pdf_stm_buffer_t struct

[vivekparadkar]

Hi All,

In pdf-stm-filter-apply function we are checking for the return value of  
filters's apply_fn. If the return value is PDF_ENINPUT
the cache is refilled with encoded data if no other filters are present in  
the chain.


In case of CCITT fax filter the data in the cache before it is refilled  
might be useful for properly decoding the data.
Every time CCITT decoder is called it checks for EOL code since according  
to stnd EOL code should be present before the first
line of image.
The decoder stops only after encoutering the EOL at the end of line.

So if entire data of the stream encoded with the CCITT fax filter is not  
present in the buffer cache then it might not decode
it properly or will behave in unpredicted way.
For proper decoding, entire CCITT encoded data should be present in the  
cache before filter is applied on it.

Thanks and Regards,

Vivek