Coverage Summary for Class: Application (lzwpack)

Class	Method, %	Line, %
Application$	0% (0/ 13)	0% (0/ 22)
Application$$anon$1	0% (0/ 4)	0% (0/ 10)
Application$OperationMode$	0% (0/ 1)	0% (0/ 1)
Application$OperationMode$Compress$	0% (0/ 1)	0% (0/ 1)
Application$OperationMode$Decompress$	0% (0/ 1)	0% (0/ 1)
Application$Options	0% (0/ 1)	0% (0/ 1)
Application$Options$	0% (0/ 1)	0% (0/ 1)
total	0% (0/ 22)	0% (0/ 37)

1 package lzwpack
2 
3 import java.nio.file.{Path, Paths}
4 
5 import cats.effect.{IO, Sync}
6 import fs2.{Sink, Stream}
7 
8 object Application {
9   sealed trait OperationMode
10   object OperationMode {
11     case object Compress extends OperationMode
12     case object Decompress extends OperationMode
13   }
14 
15   case class Options(path: Path = Paths.get("."), mode: OperationMode = OperationMode.Compress, maxCodeSize: Int = MaxCodeSize)
16 
17   def options = new scopt.OptionParser[Options]("lzwpack") {
18     head("lzwpack", "LZW compression utility")
19 
20     opt[Unit]('d', "decompress") action { (_, opts) =>
21       opts.copy(mode = OperationMode.Decompress)
22     } text "decompress input file instead of compression"
23 
24     opt[Int]('b', "bits") action { (n, opts) => opts.copy(maxCodeSize = n) } validate { n =>
25       if (n >= 9 && n <= 16) success
26       else failure("Code size must be between 9 and 16")
27     } text "the maximum number of bits to use for each code"
28 
29     arg[String]("path") action { (path, opts) => opts.copy(path = Paths.get(path)) }
30 
31     help("help").text("prints this usage text")
32   }
33 
34   // Use compress(1) compatible alphabet by default
35   import Alphabet.Compress
36 
37   def inputStream(path: Path): Stream[IO, Byte] = fs2.io.file.readAll[IO](path, 32768)
38 
39   def runCompress(path: Path, maxCodeSize: Int, sink: Sink[IO, Byte] = fs2.io.stdout): IO[Unit] = {
40     inputStream(path)
41       .through(compressAdaptive)
42       .through(CompressHeader.encode)
43       .to(sink)
44       .compile
45       .drain
46   }
47 
48   def runDecompress(path: Path, maxCodeSize: Int, sink: Sink[IO, Byte] = fs2.io.stdout): IO[Unit] = {
49     inputStream(path)
50       .through(CompressHeader.decode)
51       .through(decompressAdaptive)
52       .to(sink)
53       .compile
54       .drain
55   }
56 
57   def parseOptions(args: Seq[String]): IO[Option[Options]] = IO {
58     options.parse(args, Options())
59   }
60 
61   /**
62     * Parses program options and evaluates the corresponding action.
63     * This function does not actually perform side effects; it just returns a IO instance that can then
64     * be evaluated "at the end of the universe" – the program's [[main]] method.
65     */
66   def program(args: Seq[String]): IO[Unit] = parseOptions(args) flatMap {
67     case Some(Options(path, OperationMode.Compress, maxCodeSize)) => runCompress(path, maxCodeSize)
68     case Some(Options(path, OperationMode.Decompress, maxCodeSize)) => runDecompress(path, maxCodeSize)
69     case None => IO.unit
70   }
71 
72   def main(args: Array[String]): Unit = program(args).unsafeRunSync()
73 }