if err := r.UnreadByte(); err == nil {
			t.Errorf("n = %d: expected error on UnreadByte", n)
		}
	}
}

func TestUnreadByteOthers(t *testing.T) {
	// A list of readers to use in conjunction with UnreadByte.
	var readers = []func(*Reader, byte) ([]byte, error){
		(*Reader).ReadBytes,
		(*Reader).ReadSlice,
		func(r *Reader, delim byte) ([]byte, error) {
			data, err := r.ReadString(delim)

			panic(err)
		}
		b, err = io.ReadAll(f)
		if err != nil {
			panic(err)
		}
	}
	return bytes.NewReader(b), int64(len(b))
}

func TestIssue8186(t *testing.T) {
	// Directory headers & data found in the TOC of a JAR file.
	dirEnts := []string{

import (
	"fmt"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"text/scanner"

	"cmd/asm/internal/flags"
	"cmd/internal/objabi"
	"cmd/internal/src"
)

// Input is the main input: a stack of readers and some macro definitions.
// It also handles #include processing (by pushing onto the input stack)
// and parses and instantiates macro definitions.
type Input struct {
	Stack
	includes        []string

		}
		data := buf.String()
		if len(data) > maxSpecialFileSize {
			return ErrFieldTooLong
		}
		if err := tw.writeRawFile(name, data, flag, FormatPAX); err != nil || isGlobal {
			return err // Global headers return here
		}
	}

	// Pack the main header.
	var f formatter // Ignore errors since they are expected
	fmtStr := func(b []byte, s string) { f.formatString(b, toASCII(s)) }

			for i, hdr := range hdrs {
				if i >= len(v.headers) {
					t.Fatalf("entry %d: unexpected header:\ngot %+v", i, *hdr)
				}
				if !reflect.DeepEqual(*hdr, *v.headers[i]) {
					t.Fatalf("entry %d: incorrect header:\ngot  %+v\nwant %+v", i, *hdr, *v.headers[i])
				}
			}
			if len(hdrs) != len(v.headers) {
				t.Fatalf("got %d headers, want %d headers", len(hdrs), len(v.headers))
			}

			for i, sum := range chksums {

	"cmd/internal/objabi"
	"cmd/internal/src"
)

// A Tokenizer is a simple wrapping of text/scanner.Scanner, configured
// for our purposes and made a TokenReader. It forms the lowest level,
// turning text from readers into tokens.
type Tokenizer struct {
	tok  ScanToken
	s    *scanner.Scanner
	base *src.PosBase
	line int
	file *os.File // If non-nil, file descriptor to close.
}

func (f *formatter) formatString(b []byte, s string) {
	if len(s) > len(b) {
		f.err = ErrFieldTooLong
	}
	copy(b, s)
	if len(s) < len(b) {
		b[len(s)] = 0
	}

	// Some buggy readers treat regular files with a trailing slash
	// in the V7 path field as a directory even though the full path
	// recorded elsewhere (e.g., via PAX record) contains no trailing slash.
	if len(s) > len(b) && b[len(b)-1] == '/' {

	TypeXHeader = 'x'

	// Type 'g' is used by the PAX format to store key-value records that
	// are relevant to all subsequent files.
	// This package only supports parsing and composing such headers,
	// but does not currently support persisting the global state across files.
	TypeXGlobalHeader = 'g'

	// Type 'S' indicates a sparse file in the GNU format.
	TypeGNUSparse = 'S'

			// Otherwise one bad and unneeded field in an otherwise okay struct
			// makes the whole program not compile. Much of the time these
			// structs are in system headers that cannot be corrected.
			continue
		}

		// Round off up to talign, assumed to be a power of 2.
		off = (off + talign - 1) &^ (talign - 1)

		if f.ByteOffset > off {

pkg encoding/pem, func EncodeToMemory(*Block) []uint8
pkg encoding/pem, type Block struct
pkg encoding/pem, type Block struct, Bytes []uint8
pkg encoding/pem, type Block struct, Headers map[string]string
pkg encoding/pem, type Block struct, Type string
pkg encoding/xml, const Header ideal-string
pkg encoding/xml, func CopyToken(Token) Token
pkg encoding/xml, func Escape(io.Writer, []uint8)