Extract the files from inside Necesse `res.data` file

necesse_extract.ps1

if (![System.BitConverter]::IsLittleEndian) {
	throw [System.BitConverter]::IsLittleEndian
}

$resources = [System.IO.FileStream]::new(
	'res.data',
	[System.IO.FileMode]::Open,
	[System.IO.FileAccess]::Read
)

$number = [byte[]]::new(4)
Function ReadNumber { Param([switch]$safe)
	if ($resources.Read($number, 0, $number.Count) -eq $number.Count) {
		[System.BitConverter]::ToInt32($number, 0)
	}
	elseif (!$safe) {
		throw 'EOF'
	}
}

Function ReadString { Param($length)
	$bytes = [byte[]]::new($length)
	if ($resources.Read($bytes, 0, $length) -ne $length) {
		throw 'EOF'
	}
	[System.Text.Encoding]::UTF8.GetString($bytes)
}

Function Seek { Param($bytes)
	$resources.Seek($bytes, [System.IO.SeekOrigin]::Current) | Out-Null
}

$copied = $True
$copying = [byte[]]::new(4KB),[byte[]]::new(4KB)
Function Read { Param($length)
	$resources.ReadAsync($copying[!$copied], 0, [math]::Min($copying[0].Count, $length))
}

Seek 4
try {
	for ($length; $length = ReadNumber -safe;) {
		$name   = ReadString $length
		$length = ReadNumber
		
		"$name`t$($length / 1KB)kb" -replace '(?<=\.\d{2})\d+(?=kb)',''
		$name = '_extracted/' + $name
		$next = Read $length
		
		New-Item -Type Directory -Force ($name -replace '/[^/]+$','') | Out-Null
		$file = [System.IO.FileStream]::new(
			$name,
			[System.IO.FileMode]::CreateNew,
			[System.IO.FileAccess]::Write
		)
		$write = $NULL
		try {
			for (
				$read;
				$next;
				$write = $file.WriteAsync($copying[$copied], 0, $read)
			) {
				if (!($read = $next.Result)) {
					throw 'EOF'
				}
				
				$copied = !$copied
				if ($write) {
					$write.Wait()
				}
				
				if ($length -= $read) {
					$next = Read $length
				}
				else {
					$next = $NULL
				}
			}
		}
		finally {
			if ($write) {
				$write.Wait()
			}
			$file.Close()
		}
	}
}
finally {
	$resources.Close()
}