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https://issues.apache.org/jira/browse/COMPRESS-477?focusedWorklogId=382121&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-382121
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ASF GitHub Bot logged work on COMPRESS-477:
-------------------------------------------

                Author: ASF GitHub Bot
            Created on: 05/Feb/20 07:59
            Start Date: 05/Feb/20 07:59
    Worklog Time Spent: 10m 
      Work Description: PeterAlfreadLee commented on pull request #92: 
COMPRESS-477 : "open when actually needed" for MultiReadOnlySeekableByteChannel
URL: https://github.com/apache/commons-compress/pull/92
 
 
   Please refer (#90)[https://github.com/apache/commons-compress/pull/90]
   
   When I was adding zip64 support for split zip, I encountered a problem : 
   When adding testcases in `Zip64SupportIT`, I created a split zip with 
10,000+ split segments. Then I found that I was unable to unzip it because 
there would be too many open files when extracting it. We can oepn the files 
when actually needed and therefore we can successfully extract such split zips 
with great amount of segments.
   
   I have set a threshold of 20 in `MultiReadOnlySeekableByteChannel`. The 
"open when actually needed" procedure will only work when the number of split 
segments is greater than the threshold.
   
   Actually this is a pretty rare case cause most split zips would not have too 
many segments. So you can decide whether to merge this PR or not. :-)
 
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Issue Time Tracking
-------------------

    Worklog Id:     (was: 382121)
    Time Spent: 14h 10m  (was: 14h)

> Support for split zip files
> ---------------------------
>
>                 Key: COMPRESS-477
>                 URL: https://issues.apache.org/jira/browse/COMPRESS-477
>             Project: Commons Compress
>          Issue Type: New Feature
>          Components: Archivers
>    Affects Versions: 1.18
>            Reporter: Luís Filipe Nassif
>            Priority: Major
>              Labels: zip
>             Fix For: 1.20
>
>          Time Spent: 14h 10m
>  Remaining Estimate: 0h
>
> It would be very useful to support splitted zip files. I've read 
> [https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT] and understood 
> that simply concatenating the segments and removing the split signature 
> 0x08074b50 from first segment would be sufficient, but it is not that simple 
> because compress fails with exception below:
> {code}
> Caused by: java.util.zip.ZipException: archive's ZIP64 end of central 
> directory locator is corrupt.
>  at 
> org.apache.commons.compress.archivers.zip.ZipFile.positionAtCentralDirectory64(ZipFile.java:924)
>  ~[commons-compress-1.18.jar:1.18]
>  at 
> org.apache.commons.compress.archivers.zip.ZipFile.positionAtCentralDirectory(ZipFile.java:901)
>  ~[commons-compress-1.18.jar:1.18]
>  at 
> org.apache.commons.compress.archivers.zip.ZipFile.populateFromCentralDirectory(ZipFile.java:621)
>  ~[commons-compress-1.18.jar:1.18]
>  at 
> org.apache.commons.compress.archivers.zip.ZipFile.<init>(ZipFile.java:295) 
> ~[commons-compress-1.18.jar:1.18]
>  at 
> org.apache.commons.compress.archivers.zip.ZipFile.<init>(ZipFile.java:280) 
> ~[commons-compress-1.18.jar:1.18]
>  at 
> org.apache.commons.compress.archivers.zip.ZipFile.<init>(ZipFile.java:236) 
> ~[commons-compress-1.18.jar:1.18]
> {code}



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