[jira] [Comment Edited] (COMPRESS-320) File listing and random access of 7Z files

["Dawid Weiss (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/COMPRESS-320?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15196144#comment-15196144 ] 

Dawid Weiss edited comment on COMPRESS-320 at 3/15/16 8:16 PM:
---------------------------------------------------------------

You're right. I think the confusion is partly because we have three separate issues mixed together here:

# efficient "skipping" of entries, while iterating over them (no need to decompress anything if all entries of a block are skipped),
# exposing/ listing of all entries in the archive (and their metadata),
# random access to any entry in the archive.

My patch fully addressed issue number 1. Issue number 2 is entirely doable (and relatively easy to do) by exposing the data already contained in the Archive class (as far as I can remember). Issue number 3 is (to me) not solvable (and will lead to odd problem reports) as it can lead to exponential decompression times for an archive with large block sizes.

I think it does make sense to create these three separate issues as subtasks (or top-level issues) and then apply a close/fix-for to them in accordance with the reality.


was (Author: dweiss):
You're right. I still the confusion is partly because we have three separate issues mixed together here:

# efficient "skipping" of entries, while iterating over them (no need to decompress anything if all entries of a block are skipped),
# exposing/ listing of all entries in the archive (and their metadata),
# random access to any entry in the archive.

My patch fully addressed issue number 1. Issue number 2 is entirely doable (and relatively easy to do) by exposing the data already contained in the Archive class (as far as I can remember). Issue number 3 is (to me) not solvable (and will lead to odd problem reports) as it can lead to exponential decompression times for an archive with large block sizes.

I think it does make sense to create these three separate issues as subtasks (or top-level issues) and then apply a close/fix-for to them in accordance with the reality.

> File listing and random access of 7Z files
> ------------------------------------------
>
>                 Key: COMPRESS-320
>                 URL: https://issues.apache.org/jira/browse/COMPRESS-320
>             Project: Commons Compress
>          Issue Type: Improvement
>          Components: Archivers
>            Reporter: Bill Chen
>            Priority: Minor
>
> I guess these must be one of the most wanted features and it should be very simple to implement (as I have done one in 126 lines).
> Most (if not all) of the infrastructure is already there, including an index of all files. And, with some careful coding, the capability to read any of them in any order concurrently was not difficult to add.
> My code uses loads of lambda and reflection stuff, but I am happy to contribute a clean Java 5/6 implementation.



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