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/*
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 * Original technique from http://naterice.com/zip-and-unzip-files-using-the-windows-shell-and-vbscript/
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 */
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function create_zip(dst)
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{
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	var header = "\x50\x4b\x05\x06" +
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		"\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
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		"\x00\x00\x00\x00\x00\x00\x00\x00\x00";
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	/*
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	 * Trick to write a binary file regardless of the system locale
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	 */
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	var outw = new ActiveXObject("ADODB.Stream");
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	outw.Type = 2;
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	outw.Open();
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	outw.WriteText(header);
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	outw.Position = 0;
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	var outa = new ActiveXObject("ADODB.Stream");
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	outa.Type = 2;
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	outa.Charset = "windows-1252";
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	outa.Open()
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	outw.CopyTo(outa);
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	outa.SaveToFile(dst, 2);
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	outw.Close();
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	outa.Close();
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}
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function basename(path)
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{
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	var a = path.split("\\");
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	var b = a.slice(-1);
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	return b[0];
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}
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function fileeq(a, b)
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{
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	return basename(a).toLowerCase() == basename(b).toLowerCase();
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}
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function zip(src, dst)
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{
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	var shell = new ActiveXObject('Shell.Application');
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	var fso = new ActiveXObject('Scripting.FileSystemObject');
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	/*
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	 * Normalize paths, required by the shell commands
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	 */
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	src = fso.GetAbsolutePathName(src);
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	dst = fso.GetAbsolutePathName(dst);
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	/*
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	 * Create an empty zip file if necessary
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	 */
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	if (!fso.FileExists(dst)) {
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		create_zip(dst);
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	}
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	/*
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	 * Check for duplicates
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	 */
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	var zipfile = shell.Namespace(dst);
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	var files = zipfile.items();
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	var count = files.Count;
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	for (var i = 0; i < files.Count; i++) {
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		if (fileeq(files.Item(i).Name, src)) {
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			return;
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		}
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	}
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	zipfile.CopyHere(src);
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	/*
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	 * Wait for completion, but data can be stale on network shares, so we
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	 * abort after 5 seconds.
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	 */
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	var max_tries = 50;
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	while (count == zipfile.items().Count) {
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		WScript.Sleep(100);
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		if (max_tries-- == 0) {
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			return;
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		}
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	}
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}
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