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    SubjectRe: [RFC] CryptoAPI & Compression
    David Woodhouse wrote:
    > On Fri, 2005-04-01 at 18:57 +0400, Artem B. Bityuckiy wrote:
    >
    >>Yes, the compression will be better. But the implementation will be more
    >>complicated.
    >>We can try to use the "bound" functions to predict how many bytes to
    >>pass to the deflate's input, but there is no guarantee they'll fit into
    >>the output buffer. In this case we'll need to try again.
    >
    >
    > Can we not predict the maximum number of bytes it'll take to flush the
    > stream when we're not using Z_SYNC_FLUSH?

    AFAIU, no. Zlib may eat a lot of input and do not produce much output, but
    on Z_FINISH it may ask an undetermined amount of additional output space.
    So, we must even regulate the amount of input we pass to zlib_deflate().
    In case of Z_SYNC_FLUSH, things are more determined.

    Another question, does JFFSx *really* need the peaces of a 4K page to be
    independently uncompressable? It it wouldn't be required, we would achieve
    better compression if we have saved the zstream state. :-) But it is too
    late to change things at least for JFFS2.

    --
    Best Regards,
    Artem B. Bityuckiy,
    St.-Petersburg, Russia.
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