decode method Null safety

void decode(
  1. Uint16List input,
  2. int si,
  3. int nx,
  4. int ox,
  5. int ny,
  6. int oy,
  7. int mx
)

Implementation

static void decode(
    Uint16List input, int si, int nx, int ox, int ny, int oy, int mx) {
  final w14 = (mx < (1 << 14));
  final n = (nx > ny) ? ny : nx;
  var p = 1;
  int p2;

  // Search max level
  while (p <= n) {
    p <<= 1;
  }

  p >>= 1;
  p2 = p;
  p >>= 1;

  final a_b = [0, 0];

  // Hierarchical loop on smaller dimension n
  while (p >= 1) {
    var py = si;
    final ey = si + oy * (ny - p2);
    final oy1 = oy * p;
    final oy2 = oy * p2;
    final ox1 = ox * p;
    final ox2 = ox * p2;
    int i00, i01, i10, i11;

    // Y loop
    for (; py <= ey; py += oy2) {
      var px = py;
      final ex = py + ox * (nx - p2);

      // X loop
      for (; px <= ex; px += ox2) {
        final p01 = px + ox1;
        final p10 = px + oy1;
        final p11 = p10 + ox1;

        // 2D wavelet decoding
        if (w14) {
          wdec14(input[px], input[p10], a_b);
          i00 = a_b[0];
          i10 = a_b[1];

          wdec14(input[p01], input[p11], a_b);
          i01 = a_b[0];
          i11 = a_b[1];

          wdec14(i00, i01, a_b);
          input[px] = a_b[0];
          input[p01] = a_b[1];

          wdec14(i10, i11, a_b);
          input[p10] = a_b[0];
          input[p11] = a_b[1];
        } else {
          wdec16(input[px], input[p10], a_b);
          i00 = a_b[0];
          i10 = a_b[1];

          wdec16(input[p01], input[p11], a_b);
          i01 = a_b[0];
          i11 = a_b[1];

          wdec16(i00, i01, a_b);
          input[px] = a_b[0];
          input[p01] = a_b[1];

          wdec16(i10, i11, a_b);
          input[p10] = a_b[0];
          input[p11] = a_b[1];
        }
      }

      // Decode (1D) odd column (still in Y loop)
      if (nx & p != 0) {
        final p10 = px + oy1;

        if (w14) {
          wdec14(input[px], input[p10], a_b);
          i00 = a_b[0];
          input[p10] = a_b[1];
        } else {
          wdec16(input[px], input[p10], a_b);
          i00 = a_b[0];
          input[p10] = a_b[1];
        }

        input[px] = i00;
      }
    }

    // Decode (1D) odd line (must loop in X)
    if (ny & p != 0) {
      var px = py;
      final ex = py + ox * (nx - p2);

      for (; px <= ex; px += ox2) {
        final p01 = px + ox1;

        if (w14) {
          wdec14(input[px], input[p01], a_b);
          i00 = a_b[0];
          input[p01] = a_b[1];
        } else {
          wdec16(input[px], input[p01], a_b);
          i00 = a_b[0];
          input[p01] = a_b[1];
        }

        input[px] = i00;
      }
    }

    // Next level
    p2 = p;
    p >>= 1;
  }
}