Make ZiparchiveInputStream support as much of the zip package as possible
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Key: SANDBOX-293
URL: https://issues.apache.org/jira/browse/SANDBOX-293
Project: Commons Sandbox
Issue Type: Improvement
Components: Compress
Reporter: Stefan Bodewig
Copying something I sent to the dev list:
> Generally speaking the InputStream metaphor doesn't work for ZIP
> archives.
> A ZIP archive contains what is called "central directory" at the end
> of the archive. This is the only authoritative source telling you
> what is inside that archive.
> Before the central directory there are the actualy contents (among
> other things). For each entry you get a local file header describing
> the entry (duplicating information from the central directory) and the
> actual contents. The central directory contains a pointer to the
> local file data.
> java.util.ZipInputStream reads the stream in sequence and creates
> ZipEntries as it finds local file information.
> ZipFile (our, not the one in java.util.zip - I don't know what the
> later does) reads the archve from the back and parses the central
> directory to see what is inside the archive.
> It is not uncommon for archiver to "update" existing archives by
> adding new local file data at the end and rewrite the central
> directory without removing the old local file data. In such a case
> java.util.ZipInputStream will find entries that shouldn't be there or
> worse old data for updated entries.
Having said that, the only alternative for people who really only have a stream
and
not a file is java.util.ZipInputStream and we cn at least do better than that.
We need a ZipArchiveInputStream that shares the broken "if there is local file
data
there is a ZipArchiveEntry" logic with ZipInputStream but uses the data parsing
code of ZipFile to provide all the benefits of encoding support, access to
external
attributes and parsed extra fields.
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