Obtain Post ID from within ‘the_content’ filter function

Hi,
I’m writing a plugin which needs to add some data to the end of a post, based on statistics generated by the comments. Is there any way to obtain a post’s ID from within the function called by ‘the_content’? There doesn’t appear to be a hook which passes an array of data about a post like there is with some of the comment hooks.

Thanks for your time,

Solar