"cmd/internal/src"
)

// A Slice reads from a slice of Tokens.
type Slice struct {
	tokens []Token
	base   *src.PosBase
	line   int
	pos    int
}

func NewSlice(base *src.PosBase, line int, tokens []Token) *Slice {
	return &Slice{
		tokens: tokens,
		base:   base,
		line:   line,
		pos:    -1, // Next will advance to zero.
	}
}

func (s *Slice) Next() ScanToken {
	s.pos++

// it has sufficient capacity, the destination is resliced to accommodate the
// new elements. If it does not, a new underlying array will be allocated.
// Append returns the updated slice. It is therefore necessary to store the
// result of append, often in the variable holding the slice itself:
//
//	slice = append(slice, elem1, elem2)
//	slice = append(slice, anotherSlice...)
//

}

// Compare returns an integer comparing two byte slices lexicographically.
// The result will be 0 if a == b, -1 if a < b, and +1 if a > b.
// A nil argument is equivalent to an empty slice.
func Compare(a, b []byte) int {
	return bytealg.Compare(a, b)
}

// explode splits s into a slice of UTF-8 sequences, one per Unicode code point (still slices of bytes),
// up to a maximum of n byte slices. Invalid UTF-8 sequences are chopped into individual bytes.

// 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
}

// Len returns the number of bytes of the unread portion of the
// slice.
func (r *Reader) Len() int {

// scanning lines, a [SplitFunc] can return (0, nil, nil) to signal the
// [Scanner] to read more data into the slice and try again with a
// longer slice starting at the same point in the input.
//
// The function is never called with an empty data slice unless atEOF
// is true. If atEOF is true, however, data may be non-empty and,
// as always, holds unprocessed text.

// Bytes returns a slice of length b.Len() holding the unread portion of the buffer.
// The slice is valid for use only until the next buffer modification (that is,
// only until the next call to a method like [Buffer.Read], [Buffer.Write], [Buffer.Reset], or [Buffer.Truncate]).
// The slice aliases the buffer content at least until the next buffer modification,
// so immediate changes to the slice will affect the result of future reads.

//go:linkname runtime_arena_arena_New
func runtime_arena_arena_New(arena unsafe.Pointer, typ any) any

// Mark as noescape to avoid escaping the slice header.
//
//go:noescape
//go:linkname runtime_arena_arena_Slice
func runtime_arena_arena_Slice(arena unsafe.Pointer, slice any, cap int)

//go:linkname runtime_arena_arena_Free
func runtime_arena_arena_Free(arena unsafe.Pointer)

//go:linkname runtime_arena_heapify

		}

		if string(b) != tt.s {
			t.Errorf("slice changed to %s; want %s", b, tt.s)
		}
		if len(tt.a) > 0 {
			if want := tt.a[len(tt.a)-1] + "z"; string(x) != want {
				t.Errorf("last appended result was %s; want %s", x, want)
			}
		}
	}
}

// Test case for any function which accepts and returns a byte slice.
// For ease of creation, we write the input byte slice as a string.
type StringTest struct {

	a := arena.NewArena()
	defer a.Free()

	tt := arena.New[T1](a)
	tt.n = 1

	ts := arena.MakeSlice[T1](a, 99, 100)
	if len(ts) != 99 {
		t.Errorf("Slice() len = %d, want 99", len(ts))
	}
	if cap(ts) != 100 {
		t.Errorf("Slice() cap = %d, want 100", cap(ts))
	}
	ts[1].n = 42
}

func TestSmokeLarge(t *testing.T) {
	a := arena.NewArena()
	defer a.Free()
	for i := 0; i < 10*64; i++ {

	}()

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

// Was a bug: used to give EOF reading empty slice at EOF.
func TestReadEmptyAtEOF(t *testing.T) {
	b := new(Buffer)
	slice := make([]byte, 0)
	n, err := b.Read(slice)
	if err != nil {
		t.Errorf("read error: %v", err)
	}
	if n != 0 {
		t.Errorf("wrong count; got %d want 0", n)
	}
}