integrating changes from #21768

Signed-off-by: Mario Loriedo <mario.loriedo@gmail.com>

pkg/machine/compression/decompress.go

@@ -61,12 +61,12 @@ func newDecompressor(compressedFilePath string, compressedFileContent []byte) (d
 		return newZipDecompressor(compressedFilePath)
 	case compressionType == archive.Uncompressed:
 		return newUncompressedDecompressor(compressedFilePath)
-	// macOS gzipped VM images are sparse. As a result a
-	// special decompressor is required: it uses crc os.CopySparse
-	// instead of io.Copy and std lib gzip instead of klauspost/pgzip
-	// (even if it's slower).
+	// Using special compressors on MacOS because default ones
+	// in c/image/pkg/compression are slow with sparse files.
 	case compressionType == archive.Gzip && os == macOs:
 		return newGzipDecompressor(compressedFilePath)
+	case compressionType == archive.Zstd && os == macOs:
+		return newZstdDecompressor(compressedFilePath)
 	default:
 		return newGenericDecompressor(compressedFilePath)
 	}

pkg/machine/compression/uncompressed.go

@@ -2,8 +2,6 @@ package compression
 
 import (
 	"io"
-
-	crcOs "github.com/crc-org/crc/v2/pkg/os"
 )
 
 type uncompressedDecompressor struct {
@@ -15,7 +13,8 @@ func newUncompressedDecompressor(compressedFilePath string) (*uncompressedDecomp
 	return &uncompressedDecompressor{*d}, err
 }
 
-func (*uncompressedDecompressor) decompress(w WriteSeekCloser, r io.Reader) error {
-	_, err := crcOs.CopySparse(w, r)
+func (d *uncompressedDecompressor) decompress(w WriteSeekCloser, r io.Reader) error {
+	sparseWriter := NewSparseWriter(w)
+	_, err := io.Copy(sparseWriter, r)
 	return err
 }

pkg/machine/compression/zstd.go

@@ -0,0 +1,34 @@
+package compression
+
+import (
+	"io"
+
+	"github.com/klauspost/compress/zstd"
+)
+
+type zstdDecompressor struct {
+	genericDecompressor
+	zstdReader *zstd.Decoder
+}
+
+func newZstdDecompressor(compressedFilePath string) (*zstdDecompressor, error) {
+	d, err := newGenericDecompressor(compressedFilePath)
+	return &zstdDecompressor{*d, nil}, err
+}
+
+func (d *zstdDecompressor) decompress(w WriteSeekCloser, r io.Reader) error {
+	zstdReader, err := zstd.NewReader(r)
+	if err != nil {
+		return err
+	}
+	d.zstdReader = zstdReader
+
+	sparseWriter := NewSparseWriter(w)
+	_, err = io.Copy(sparseWriter, zstdReader)
+	return err
+}
+
+func (d *zstdDecompressor) close() {
+	d.zstdReader.Close()
+	d.genericDecompressor.close()
+}