// io.ByteScanner, and io.RuneScanner interfaces by reading from
// a byte slice.
// Unlike a [Buffer], a Reader is read-only and supports seeking.
// The zero value for Reader operates like a Reader of an empty slice.
type Reader struct {
	s        []byte
	i        int64 // current reading index
	prevRune int   // index of previous rune; or < 0
}

	clear(b)
	return len(b), nil
}

// mustReadFull is like io.ReadFull except it returns
// io.ErrUnexpectedEOF when io.EOF is hit before len(b) bytes are read.
func mustReadFull(r io.Reader, b []byte) (int, error) {
	n, err := tryReadFull(r, b)
	if err == io.EOF {
		err = io.ErrUnexpectedEOF
	}
	return n, err
}

// tryReadFull is like io.ReadFull except it returns

			// ReadFull returns ErrUnexpectedEOF.
			return dst[:n], err
		}
		dst = dst[:n]
		if err == io.ErrUnexpectedEOF {
			return dst, io.EOF
		}
	}
	// Read until next line.
	in, err := r.buf.ReadBytes('\n')
	dst = append(dst, in...)
	return dst, err
}

// csvSplitSize is the size of each block.
// Blocks will read this much and find the first following newline.

// calculation repeatedly under hash.Reader.
type Options struct {
	MD5Hex     string
	SHA256Hex  string
	Size       int64
	ActualSize int64
	DisableMD5 bool
	ForceMD5   []byte
}

// NewReaderWithOpts is like NewReader but takes `Options` as argument, allowing
// callers to indicate if they want to disable md5sum checksum.
func NewReaderWithOpts(ctx context.Context, src io.Reader, opts Options) (*Reader, error) {

				err = ErrChecksum
			}
		} else {
			// If there's not a data descriptor, we still compare
			// the CRC32 of what we've read against the file header
			// or TOC's CRC32, if it seems like it was set.
			if r.f.CRC32 != 0 && r.hash.Sum32() != r.f.CRC32 {
				err = ErrChecksum
			}
		}
	}
	r.err = err
	return
}

func (r *checksumReader) Close() error { return r.rc.Close() }