<p>I'm looking for a wrapper that distills zlib to:</p>

<ol>
<li>OpenZipFile()</li>
<li>GetItemInfo(n)</li>
<li>UnzipItem(n)  // Bonus points for unzipping recursively if item n is a directory.</li>
</ol>

<p>I see a lot of wrappers around the zlib library on, say, codeproject.com but they are all platform-specific in order to provide the added platform-specific functionality of unzipping to file/memory buffer/pipe.</p>

In the zlib source archive, there is a contribution named "minizip".
"minizip" is a set of files you can use to play with .zip files. Basic services you need are already there :
unzOpen
unzLocateFile
unzOpenCurrentFile
unzGetCurrentFileInfo
unzCloseCurrentFile
unzClose
Of course, this is not object oriented (and I'm sure that was not the goal of the creator of minizip), but writing a simple object oriented wrapper should be easy.