# two parameter: the dest dir to be unzipped, the src zip file name, also in dest dir
# if exists a folder or file of same name in zipped archieve, it will be deleted.   
function unzip([string] $path, [string]$zipFile)
{	
	if (!(test-path -path $zipFile))
	{
		return $false;
	}
	if ((get-item -path $zipFile).length -eq 0)
	{
		return $false;
	}

	$shell=new-object -com shell.application;
		
	$ZipFolder = $shell.namespace("$ZipFile");
	# make sure the path is created	
	if (!(test-path -path $path))
	{
		mkdir $path | out-null;	
				
	}
	else
	{			
		foreach ($srcItem in $ZipFolder.Items())
		{
			$dstItemPath = join-path -path $path -childpath $srcItem.path;						
			
			$exists = Test-Path -Path $dstItemPath;
   
			if ($exists) # If the item doesn't exist in the desination directory...		
			{							
				Remove-Item -Path $dstItemPath -Recurse;			
			}
		}
	}
	$destinationFolder=$shell.namespace("$path");
	$destinationFolder.Copyhere($ZipFolder.items());
	return $true;	
}

# two parameter: the source dir to be zipped, the dst zip file name which will be deleted if exists.
function zip([string] $path, [string] $zipFile)
{
	# make sure the path is created
	#echo "path=$path,zipFile=$zipFile"
	if (!(test-path -path $path))
	{
		return $false;
	}
	if ((get-childitem -path $path) -eq $null)
	{
		return $false;
	}

	# make sure no zip file does NOT exists, because the UI need human interaction

	if (test-path -path $zipFile)
	{
		Echo "removing..."
		### becareful!!! PS is really stupid to handle files!!
		# you need to clear content, not to remove the file!!!!!!!!!!
		#remove-item -path $zipFile -force;	
		clear-content -path $zipFile;	
	}
	else
	{
		new-item -path $zipFile -type "file" | out-null;
	}
	 
	set-content $zipFile ("PK" + [char]5 + [char]6 + ("$([char]0)" * 18));
	
	$src=get-item $path; 

	$shell=new-object -com shell.application;		

	$dst = $shell.namespace("$zipFile");		
	$dst.Synchronize();	
	foreach ($item in $src)
	{		
		$dst.Copyhere($item.fullname);	
		#$dst.Synchronize();	
	}
	
	#$dst.Synchronize();
	start-sleep 3
	return $true;
}