// client may instead provide a custom split function.
//
// Scanning stops unrecoverably at EOF, the first I/O error, or a token too
// large to fit in the [Scanner.Buffer]. When a scan stops, the reader may have
// advanced arbitrarily far past the last token. Programs that need more
// control over error handling or large tokens, or must run sequential scans
// on a reader, should use [bufio.Reader] instead.
type Scanner struct {

	opReadRune4 readOp = 4  // Read rune of size 4.
)

// ErrTooLarge is passed to panic if memory cannot be allocated to store data in a buffer.
var ErrTooLarge = errors.New("bytes.Buffer: too large")
var errNegativeRead = errors.New("bytes.Buffer: reader returned negative count from Read")

const maxInt = int(^uint(0) >> 1)

// Bytes returns a slice of length b.Len() holding the unread portion of the buffer.

	n := len(b) * count

	if len(b) == 0 {
		return []byte{}
	}

	// Past a certain chunk size it is counterproductive to use
	// larger chunks as the source of the write, as when the source
	// is too large we are basically just thrashing the CPU D-cache.
	// So if the result length is larger than an empirically-found
	// limit (8KB), we stop growing the source string once the limit

before a garbage collection delays that cycle. Less frequent cycles means
the CPU cost of the garbage collector is incurred less frequently.

This functionality in this package is mostly captured in the Arena type.
Arenas allocate large chunks of memory for Go values, so they're likely to
be inefficient for allocating only small amounts of small Go values. They're
best used in bulk, on the order of MiB of memory allocated on each use.

type int int

// uint is an unsigned integer type that is at least 32 bits in size. It is a
// distinct type, however, and not an alias for, say, uint32.
type uint uint

// uintptr is an integer type that is large enough to hold the bit pattern of
// any pointer.
type uintptr uintptr

// byte is an alias for uint8 and is equivalent to uint8 in all ways. It is
// used, by convention, to distinguish byte values from 8-bit unsigned

				t.Errorf("bad written data at %d %d", startLen, growLen)
			}
		}
	}
}

func TestGrowOverflow(t *testing.T) {
	defer func() {
		if err := recover(); err != ErrTooLarge {
			t.Errorf("after too-large Grow, recover() = %v; want %v", err, ErrTooLarge)
		}
	}()

	buf := NewBuffer(make([]byte, 1))
	const maxInt = int(^uint(0) >> 1)
	buf.Grow(maxInt)
}

	case scanner.Int, '(':
		p.back()
		x := int64(p.expr())
		if p.arch.Family == sys.ARM64 {
			if x >= 64 {
				p.errorf("register shift count too large: %s", str)
			}
			count = int16((x & 63) << 10)
		} else {
			if x >= 32 {
				p.errorf("register shift count too large: %s", str)
			}
			count = int16((x & 31) << 7)
		}
	default:
		p.errorf("unexpected %s in register shift", tok.String())
	}

	// Second, if ContentErr==nil, the content should match Content.
	// If content is large, an alternative to setting Content is to set File,
	// which names a file in the testdata/ directory containing the
	// uncompressed expected content.
	// If content is very large, an alternative to setting Content or File
	// is to set Size, which will then be checked against the header-reported size

var writeTests = []WriteTest{
	{
		Name:   "foo",
		Data:   []byte("Rabbits, guinea pigs, gophers, marsupial rats, and quolls."),
		Method: Store,
		Mode:   0666,
	},
	{
		Name:   "bar",
		Data:   nil, // large data set in the test
		Method: Deflate,
		Mode:   0644,
	},
	{
		Name:   "setuid",
		Data:   []byte("setuid file"),
		Method: Deflate,
		Mode:   0755 | fs.ModeSetuid,
	},
	{
		Name:   "setgid",

}

const minReadBufferSize = 16
const maxConsecutiveEmptyReads = 100

// NewReaderSize returns a new [Reader] whose buffer has at least the specified
// size. If the argument io.Reader is already a [Reader] with large enough
// size, it returns the underlying [Reader].
func NewReaderSize(rd io.Reader, size int) *Reader {
	// Is it already a Reader?
	b, ok := rd.(*Reader)
	if ok && len(b.buf) >= size {
		return b
	}