Tweaks to decode interface

internal/decompress/gzip.go

@@ -12,8 +12,6 @@ func (g GZip) Reader(src io.Reader) (io.ReadCloser, error) {
 	return zlib.NewReader(src)
 }
 
-func (g GZip) Resetable() bool { return true }
-
 func (g GZip) Reset(old, src io.Reader) error {
 	return old.(zlib.Resetter).Reset(src, nil)
 }

internal/decompress/interface.go

@@ -1,19 +1,22 @@
 package decompress
 
 import (
-	"errors"
 	"io"
 )
 
-var ErrNotResetable = errors.New("decompressor not resetable")
-
 type Decompressor interface {
 	//Creates a new decompressor reading from src.
 	Reader(src io.Reader) (io.ReadCloser, error)
-	//Reports whether Reset will work or not.
-	Resetable() bool
+}
+
+type Resetable interface {
 	//Reset attempts to re-use an old decompressor with new data.
 	//Will return ErrNotResetable if not Resetable().
 	//Must ALWAYS be provided with a reader created with Reader.
 	Reset(old, src io.Reader) error
 }
+
+type Decoder interface {
+	//Decodes a chunk of data all at once.
+	Decode(in []byte, outSize int) ([]byte, error)
+}

internal/decompress/lz4.go

@@ -12,9 +12,16 @@ func (l Lz4) Reader(r io.Reader) (io.ReadCloser, error) {
 	return io.NopCloser(lz4.NewReader(r)), nil
 }
 
-func (l Lz4) Resetable() bool { return true }
-
 func (l Lz4) Reset(old, src io.Reader) error {
 	old.(*lz4.Reader).Reset(src)
 	return nil
 }
+
+func (l Lz4) Decode(in []byte, outSize int) (out []byte, err error) {
+	out = make([]byte, outSize)
+	outLen, err := lz4.UncompressBlock(in, out)
+	if outLen < outSize {
+		out = out[:outLen]
+	}
+	return
+}

internal/decompress/lzma.go

@@ -12,7 +12,3 @@ func (l Lzma) Reader(r io.Reader) (io.ReadCloser, error) {
 	rdr, err := lzma.NewReader(r)
 	return io.NopCloser(rdr), err
 }
-
-func (l Lzma) Resetable() bool { return false }
-
-func (l Lzma) Reset(old, src io.Reader) error { return ErrNotResetable }

internal/decompress/lzo.go

@@ -16,7 +16,3 @@ func (l Lzo) Reader(r io.Reader) (io.ReadCloser, error) {
 	}
 	return io.NopCloser(bytes.NewReader(cache)), nil
 }
-
-func (l Lzo) Resetable() bool { return false }
-
-func (l Lzo) Reset(old, src io.Reader) error { return ErrNotResetable }

internal/decompress/xz.go

@@ -13,8 +13,6 @@ func (x Xz) Reader(r io.Reader) (io.ReadCloser, error) {
 	return io.NopCloser(rdr), err
 }
 
-func (x Xz) Resetable() bool { return true }
-
 func (x Xz) Reset(old, src io.Reader) error {
 	return old.(*xz.Reader).Reset(src)
 }

internal/decompress/zstd.go

@@ -15,15 +15,13 @@ func (z Zstd) Reader(src io.Reader) (io.ReadCloser, error) {
 	return r.IOReadCloser(), err
 }
 
-func (z Zstd) Resetable() bool { return true }
-
 func (z Zstd) Reset(old, src io.Reader) error {
 	return old.(*zstd.Decoder).Reset(src)
 }
 
-func (z *Zstd) Decode(in []byte) (out []byte, err error) {
+func (z Zstd) Decode(in []byte, outSize int) ([]byte, error) {
 	if z.writeToReader == nil {
 		z.writeToReader, _ = zstd.NewReader(nil)
 	}
-	return z.writeToReader.DecodeAll(in, nil)
+	return z.writeToReader.DecodeAll(in, make([]byte, outSize))
 }