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reader.go
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/
reader.go
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package lzma
import (
"bytes"
"encoding/binary"
"errors"
"io"
"github.com/ulikunitz/xz/lzma"
)
type readCloser struct {
c io.Closer
r io.Reader
}
func (rc *readCloser) Close() error {
var err error
if rc.c != nil {
err = rc.c.Close()
rc.c, rc.r = nil, nil
}
return err
}
func (rc *readCloser) Read(p []byte) (int, error) {
if rc.r == nil {
return 0, errors.New("lzma: Read after Close")
}
return rc.r.Read(p)
}
// NewReader returns a new LZMA io.ReadCloser.
func NewReader(p []byte, s uint64, readers []io.ReadCloser) (io.ReadCloser, error) {
if len(readers) != 1 {
return nil, errors.New("lzma: need exactly one reader")
}
h := bytes.NewBuffer(p)
_ = binary.Write(h, binary.LittleEndian, s)
lr, err := lzma.NewReader(multiReader(h, readers[0]))
if err != nil {
return nil, err
}
return &readCloser{
c: readers[0],
r: lr,
}, nil
}
func multiReader(b *bytes.Buffer, rc io.ReadCloser) io.Reader {
mr := io.MultiReader(b, rc)
if br, ok := rc.(io.ByteReader); ok {
return &multiByteReader{
b: b,
br: br,
mr: mr,
}
}
return mr
}
type multiByteReader struct {
b *bytes.Buffer
br io.ByteReader
mr io.Reader
}
func (m *multiByteReader) ReadByte() (byte, error) {
if m.b.Len() > 0 {
return m.b.ReadByte()
}
return m.br.ReadByte()
}
func (m *multiByteReader) Read(p []byte) (n int, err error) {
return m.mr.Read(p)
}