b.StartTimer()
	for i := range blocks {
		f(&blocks[i])
	}
}

func BenchmarkFDCT(b *testing.B) {
	benchmarkDCT(b, fdct)
}

func BenchmarkIDCT(b *testing.B) {
	benchmarkDCT(b, idct)
}

func TestDCT(t *testing.T) {
	blocks := make([]block, len(testBlocks))
	copy(blocks, testBlocks[:])

	// Append some randomly generated blocks of varying sparseness.
	r := rand.New(rand.NewSource(123))
	for i := 0; i < 100; i++ {