Re-use zstd and zlib readers

internal/decompress/zstd.go

@@ -1,16 +1,31 @@
 package decompress
 
 import (
+	"sync"
+
 	"github.com/klauspost/compress/zstd"
 )
 
-type Zstd struct{}
+type Zstd struct {
+	pool sync.Pool
+}
 
-func (z Zstd) Decompress(data []byte) ([]byte, error) {
-	rdr, err := zstd.NewReader(nil, zstd.WithDecoderLowmem(true), zstd.WithDecoderConcurrency(1))
-	if err != nil {
-		return nil, err
+func NewZstd() *Zstd {
+	return &Zstd{
+		pool: sync.Pool{
+			New: func() any {
+				rdr, _ := zstd.NewReader(nil, zstd.WithDecoderLowmem(true), zstd.WithDecoderConcurrency(1))
+				return rdr
+			},
+		},
 	}
-	defer rdr.Close()
+}
+
+func (z *Zstd) Decompress(data []byte) ([]byte, error) {
+	rdr := z.pool.Get().(*zstd.Decoder)
+	defer func() {
+		rdr.Reset(nil)
+		z.pool.Put(rdr)
+	}()
 	return rdr.DecodeAll(data, nil)
 }