//
//	import (
//		"archive/zip"
//		"bytes"
//		"io"
//		"log"
//		"os"
//	)
//
//	type zeros struct{}
//
//	func (zeros) Read(b []byte) (int, error) {
//		clear(b)
//		return len(b), nil
//	}
//
//	func main() {
//		bigZip := makeZip("big.file", io.LimitReader(zeros{}, 1<<32-1))
//		if err := os.WriteFile("/tmp/big.zip", bigZip, 0666); err != nil {
//			log.Fatal(err)
//		}
//

			got := string(readBuf[:n])
			if err != nil || got != want {
				t.Errorf("off %d, size %d = %v, %v (%q); want %q", off, size, n, err, got, want)
			}
		}
	}

}

type zeros struct{}

func (zeros) Read(p []byte) (int, error) {
	clear(p)
	return len(p), nil

//
// The err will be set to io.EOF only when one of the following occurs:
//   - Exactly 0 bytes are read and EOF is hit.
//   - Exactly 1 block of zeros is read and EOF is hit.
//   - At least 2 blocks of zeros are read.
func (tr *Reader) readHeader() (*Header, *block, error) {
	// Two blocks of zero bytes marks the end of the archive.
	if _, err := io.ReadFull(tr.r, tr.blk[:]); err != nil {