forked from bodgit/sevenzip
/
reader.go
62 lines (50 loc) · 1.04 KB
/
reader.go
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package zstd
import (
"errors"
"io"
"runtime"
"sync"
"github.com/klauspost/compress/zstd"
)
//nolint:gochecknoglobals
var zstdReaderPool sync.Pool
type readCloser struct {
c io.Closer
r *zstd.Decoder
}
func (rc *readCloser) Close() (err error) {
if rc.c != nil {
zstdReaderPool.Put(rc.r)
err = rc.c.Close()
rc.c, rc.r = nil, nil
}
return
}
func (rc *readCloser) Read(p []byte) (int, error) {
if rc.r == nil {
return 0, errors.New("zstd: Read after Close")
}
return rc.r.Read(p)
}
// NewReader returns a new Zstandard io.ReadCloser.
func NewReader(_ []byte, _ uint64, readers []io.ReadCloser) (io.ReadCloser, error) {
if len(readers) != 1 {
return nil, errors.New("zstd: need exactly one reader")
}
var err error
r, ok := zstdReaderPool.Get().(*zstd.Decoder)
if ok {
if err = r.Reset(readers[0]); err != nil {
return nil, err
}
} else {
if r, err = zstd.NewReader(readers[0]); err != nil {
return nil, err
}
runtime.SetFinalizer(r, (*zstd.Decoder).Close)
}
return &readCloser{
c: readers[0],
r: r,
}, nil
}