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https://issues.apache.org/jira/browse/COMPRESS-277?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13980742#comment-13980742
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Fabian Lange commented on COMPRESS-277:
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Hi Beluga,
You are not correct. Buffering the Cipher Input stream will not work. Because
the BIS will also only invoke skip on the CIS. CIS will always only skip a
maximum of 512 bytes. This would leave the BIS with the same problem: It is not
at the correct position.
A client cannot "skip an entry manually". How would we "modify"
getNextTarEntry() to use IOUtils#skip?
If compress would not use the now corrected implementation of skip, then the
API methods like getNextTar() entry would be broken, which is why i opened the
ticket in the first place.
> IOUtils.skip does not work as advertised
> ----------------------------------------
>
> Key: COMPRESS-277
> URL: https://issues.apache.org/jira/browse/COMPRESS-277
> Project: Commons Compress
> Issue Type: Bug
> Affects Versions: 1.8
> Reporter: Fabian Lange
> Fix For: 1.9
>
> Attachments: TarArchiveInputStream.java.patch
>
>
> I am trying to feed a TarInputStream from a CipherInputStream.
> It does not work, because IOUtils.skip() does not adhere to the contract it
> claims in javadoc:
> " * <p>This method will only skip less than the requested number of
> * bytes if the end of the input stream has been reached.</p>"
> However it does:
> long skipped = input.skip(numToSkip);
> if (skipped == 0) {
> break;
> }
> And the input stream javadoc says:
> " * This may result from any of a number of conditions; reaching end of
> file
> * before <code>n</code> bytes have been skipped is only one possibility."
> In the case of CipherInputStream, it stops at the end of each byte buffer.
> If you check the IOUtils from colleagues at commons-io, they have considered
> this case in IOUtils.skip() where they use a read to skip through the stream.
> An optimized version could combine trying to skip, then read then trying to
> skip again.
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