Removed all the pointers

low/data/reader.go

@@ -3,6 +3,7 @@ package data
 import (
 	"encoding/binary"
 	"io"
+	"io/fs"
 
 	"github.com/CalebQ42/squashfs/internal/decompress"
 )
@@ -17,10 +18,11 @@ type Reader struct {
 	curIndex       uint64
 	finalBlockSize uint64
 	blockSize      uint32
+	closed         bool
 }
 
-func NewReader(r io.Reader, d decompress.Decompressor, sizes []uint32, finalBlockSize uint64, blockSize uint32) *Reader {
-	return &Reader{
+func NewReader(r io.Reader, d decompress.Decompressor, sizes []uint32, finalBlockSize uint64, blockSize uint32) Reader {
+	return Reader{
 		r:              r,
 		d:              d,
 		sizes:          sizes,
@@ -66,6 +68,9 @@ func (r *Reader) advance() error {
 }
 
 func (r *Reader) Read(b []byte) (int, error) {
+	if r.closed {
+		return 0, fs.ErrClosed
+	}
 	curRead := 0
 	var toRead int
 	for curRead < len(b) {
@@ -83,6 +88,9 @@ func (r *Reader) Read(b []byte) (int, error) {
 }
 
 func (r *Reader) Close() error {
+	r.closed = true
+	r.r = nil
+	r.d = nil
 	if r.frag != nil {
 		if l, ok := r.frag.(*io.LimitedReader); ok {
 			if cl, ok := l.R.(io.Closer); ok {
@@ -90,6 +98,8 @@ func (r *Reader) Close() error {
 			}
 		}
 	}
+	r.frag = nil
+	r.sizes = nil
 	r.dat = nil
 	return nil
 }