}

func messWith(fileName string, corrupter func(b []byte)) (r io.ReaderAt, size int64) {
	data, err := os.ReadFile(filepath.Join("testdata", fileName))
	if err != nil {
		panic("Error reading " + fileName + ": " + err.Error())
	}
	corrupter(data)
	return bytes.NewReader(data), int64(len(data))
}

func returnCorruptCRC32Zip() (r io.ReaderAt, size int64) {
	return messWith("go-with-datadesc-sig.zip", func(b []byte) {

	w.buf = append(w.buf, p...)
	w.writeBytes += len(p)
	return len(p), nil
}

func (w *readFromWriter) ReadFrom(r io.Reader) (int64, error) {
	b, err := io.ReadAll(r)
	w.buf = append(w.buf, b...)
	w.readFromBytes += len(b)
	return int64(len(b)), err
}

// Test that calling (*Writer).ReadFrom with a partially-filled buffer
// fills the buffer before switching over to ReadFrom.

	c.byte = c.Ident("byte")
	c.int8 = c.Ident("int8")
	c.int16 = c.Ident("int16")
	c.int32 = c.Ident("int32")
	c.int64 = c.Ident("int64")
	c.uint8 = c.Ident("uint8")
	c.uint16 = c.Ident("uint16")
	c.uint32 = c.Ident("uint32")
	c.uint64 = c.Ident("uint64")
	c.uintptr = c.Ident("uintptr")
	c.float32 = c.Ident("float32")
	c.float64 = c.Ident("float64")
	c.complex64 = c.Ident("complex64")

//		g.Type = obj.TYPE_CONST;
//		g.Offset = int64($6);
//		outcode($1, $2, &$3, 0, &g);
//	}
	MOVM	0(R1), [R2,R5,R8,g] // MOVM	(R1), [R2,R5,R8,g]
	MOVM	(R1), [R2-R5] // MOVM (R1), [R2,R3,R4,R5]
	MOVM	(R1), [R2]

//	LTYPE8 cond '[' reglist ']' ',' ioreg
//	{
//		var g obj.Addr
//
//		g = nullgen;
//		g.Type = obj.TYPE_CONST;
//		g.Offset = int64($4);
//		outcode($1, $2, &g, 0, &$7);
//	}

	for _, n := range sizes {
		if isRaceBuilder && n > 4<<10 {
			continue
		}
		b.Run(valName(n), func(b *testing.B) {
			if len(bmbuf) < n {
				bmbuf = make([]byte, n)
			}
			b.SetBytes(int64(n))
			f(b, n)
		})
	}
}

var indexSizes = []int{10, 32, 4 << 10, 4 << 20, 64 << 20}

var isRaceBuilder = strings.HasSuffix(testenv.Builder(), "-race")

func BenchmarkIndexByte(b *testing.B) {