Move changes from exp2 to main

This is largely a move to simplify a lot of the readers
Also further breaks out functions.

internal/decompress/gzip.go

@@ -0,0 +1,13 @@
+package decompress
+
+import (
+	"io"
+
+	"github.com/klauspost/compress/zlib"
+)
+
+type GZip struct{}
+
+func (g GZip) Reader(src io.Reader) (io.ReadCloser, error) {
+	return zlib.NewReader(src)
+}

internal/decompress/interface.go

@@ -0,0 +1,7 @@
+package decompress
+
+import "io"
+
+type Decompressor interface {
+	Reader(src io.Reader) (io.ReadCloser, error)
+}

internal/decompress/lz4.go

@@ -0,0 +1,13 @@
+package decompress
+
+import (
+	"io"
+
+	"github.com/pierrec/lz4/v4"
+)
+
+type Lz4 struct{}
+
+func (l Lz4) Reader(r io.Reader) (io.ReadCloser, error) {
+	return io.NopCloser(lz4.NewReader(r)), nil
+}

internal/decompress/lzma.go

@@ -0,0 +1,14 @@
+package decompress
+
+import (
+	"io"
+
+	"github.com/ulikunitz/xz/lzma"
+)
+
+type Lzma struct{}
+
+func (l Lzma) Reader(r io.Reader) (io.ReadCloser, error) {
+	rdr, err := lzma.NewReader(r)
+	return io.NopCloser(rdr), err
+}

internal/decompress/lzo.go

@@ -0,0 +1,18 @@
+package decompress
+
+import (
+	"bytes"
+	"io"
+
+	"github.com/rasky/go-lzo"
+)
+
+type Lzo struct{}
+
+func (l Lzo) Reader(r io.Reader) (io.ReadCloser, error) {
+	cache, err := lzo.Decompress1X(r, 0, 0)
+	if err != nil {
+		return nil, err
+	}
+	return io.NopCloser(bytes.NewReader(cache)), nil
+}

internal/decompress/xz.go

@@ -0,0 +1,14 @@
+package decompress
+
+import (
+	"io"
+
+	"github.com/therootcompany/xz"
+)
+
+type Xz struct{}
+
+func (x Xz) Reader(r io.Reader) (io.ReadCloser, error) {
+	rdr, err := xz.NewReader(r, 0)
+	return io.NopCloser(rdr), err
+}

internal/decompress/zstd.go

@@ -0,0 +1,14 @@
+package decompress
+
+import (
+	"io"
+
+	"github.com/klauspost/compress/zstd"
+)
+
+type Zstd struct{}
+
+func (z Zstd) Reader(src io.Reader) (io.ReadCloser, error) {
+	r, err := zstd.NewReader(src)
+	return r.IOReadCloser(), err
+}