if (parallable === undefined) {
  var parallable = function (file, funct) {
    parallable.core[funct.toString()] = funct().core;
    return function () {
      var i;
      var async, worker_num, params;
      if (arguments.length > 1) {
        async = arguments[arguments.length - 2];
        worker_num = arguments[arguments.length - 1];
        params = new Array(arguments.length - 2);
        for (i = 0; i < arguments.length - 2; i++)
          params[i] = arguments[i];
      } else {
        async = arguments[0].async;
        worker_num = arguments[0].worker;
        params = arguments[0];
        delete params["async"];
        delete params["worker"];
        params = [params];
      }
      var scope = { "shared" : {} };
      var ctrl = funct.apply(scope, params);
      if (async) {
        return function (complete, error) {
          var executed = 0;
          var outputs = new Array(worker_num);
          var inputs = ctrl.pre.apply(scope, [worker_num]);
          /* sanitize scope shared because for Chrome/WebKit, worker only support JSONable data */
          for (i in scope.shared)
            /* delete function, if any */
            if (typeof scope.shared[i] == "function")
              delete scope.shared[i];
            /* delete DOM object, if any */
            else if (scope.shared[i].tagName !== undefined)
              delete scope.shared[i];
          for (i = 0; i < worker_num; i++) {
            var worker = new Worker(file);
            worker.onmessage = (function (i) {
              return function (event) {
                outputs[i] = (typeof event.data == "string") ? JSON.parse(event.data) : event.data;
                executed++;
                if (executed == worker_num)
                  complete(ctrl.post.apply(scope, [outputs]));
              }
            })(i);
            var msg = { "input" : inputs[i],
              "name" : funct.toString(),
              "shared" : scope.shared,
              "id" : i,
              "worker" : params.worker_num };
            try {
              worker.postMessage(msg);
            } catch (e) {
              worker.postMessage(JSON.stringify(msg));
            }
          }
        }
      } else {
        return ctrl.post.apply(scope, [[ctrl.core.apply(scope, [ctrl.pre.apply(scope, [1])[0], 0, 1])]]);
      }
    }
  };
  parallable.core = {};
}

function get_named_arguments(params, names) {
  if (params.length > 1) {
    var new_params = {};
    for (var i = 0; i < names.length; i++)
      new_params[names[i]] = params[i];
    return new_params;
  } else if (params.length == 1) {
    return params[0];
  } else {
    return {};
  }
}

var ccv = {
  pre : function (image) {
    if (image.tagName.toLowerCase() == "img") {
      var canvas = document.createElement("canvas");
      document.body.appendChild(image);
      canvas.width = image.offsetWidth;
      canvas.style.width = image.offsetWidth.toString() + "px";
      canvas.height = image.offsetHeight;
      canvas.style.height = image.offsetHeight.toString() + "px";
      document.body.removeChild(image);
      var ctx = canvas.getContext("2d");
      ctx.drawImage(image, 0, 0);
      return canvas;
    }
    return image;
  },

  grayscale : function (canvas) {
    var ctx = canvas.getContext("2d");
    var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
    var data = imageData.data;
    var pix1, pix2, pix = canvas.width * canvas.height * 4;
    while (pix > 0)
      data[pix -= 4] = data[pix1 = pix + 1] = data[pix2 = pix + 2] = (data[pix] * 0.3 + data[pix1] * 0.59 + data[pix2] * 0.11);
    ctx.putImageData(imageData, 0, 0);
    return canvas;
  },

  array_group : function (seq, gfunc) {
    var i, j;
    var node = new Array(seq.length);
    for (i = 0; i < seq.length; i++)
      node[i] = {"parent" : -1,
        "element" : seq[i],
        "rank" : 0};
    for (i = 0; i < seq.length; i++) {
      if (!node[i].element)
        continue;
      var root = i;
      while (node[root].parent != -1)
        root = node[root].parent;
      for (j = 0; j < seq.length; j++) {
        if( i != j && node[j].element && gfunc(node[i].element, node[j].element)) {
          var root2 = j;

          while (node[root2].parent != -1)
            root2 = node[root2].parent;

          if(root2 != root) {
            if(node[root].rank > node[root2].rank)
              node[root2].parent = root;
            else {
              node[root].parent = root2;
              if (node[root].rank == node[root2].rank)
                node[root2].rank++;
              root = root2;
            }

            /* compress path from node2 to the root: */
            var temp, node2 = j;
            while (node[node2].parent != -1) {
              temp = node2;
              node2 = node[node2].parent;
              node[temp].parent = root;
            }

            /* compress path from node to the root: */
            node2 = i;
            while (node[node2].parent != -1) {
              temp = node2;
              node2 = node[node2].parent;
              node[temp].parent = root;
            }
          }
        }
      }
    }
    var idx = new Array(seq.length);
    var class_idx = 0;
    for(i = 0; i < seq.length; i++) {
      j = -1;
      var node1 = i;
      if(node[node1].element) {
        while (node[node1].parent != -1)
          node1 = node[node1].parent;
        if(node[node1].rank >= 0)
          node[node1].rank = ~class_idx++;
        j = ~node[node1].rank;
      }
      idx[i] = j;
    }
    return {"index" : idx, "cat" : class_idx};
  },

  detect_objects : parallable("ccv.js", function (canvas, cascade, interval, min_neighbors) {
    if (this.shared !== undefined) {
      var params = get_named_arguments(arguments, ["canvas", "cascade", "interval", "min_neighbors"]);
      this.shared.canvas = params.canvas;
      this.shared.interval = params.interval;
      this.shared.min_neighbors = params.min_neighbors;
      this.shared.cascade = params.cascade;
      this.shared.scale = Math.pow(2, 1 / (params.interval + 1));
      this.shared.next = params.interval + 1;
      this.shared.scale_upto = Math.floor(Math.log(Math.min(params.canvas.width / params.cascade.width, params.canvas.height / params.cascade.height)) / Math.log(this.shared.scale));
      var i;
      for (i = 0; i < this.shared.cascade.stage_classifier.length; i++)
        this.shared.cascade.stage_classifier[i].orig_feature = this.shared.cascade.stage_classifier[i].feature;
    }
    function pre(worker_num) {
      var canvas = this.shared.canvas;
      var interval = this.shared.interval;
      var scale = this.shared.scale;
      var next = this.shared.next;
      var scale_upto = this.shared.scale_upto;
      var pyr = new Array((scale_upto + next * 2) * 4);
      var ret = new Array((scale_upto + next * 2) * 4);
      pyr[0] = canvas;
      ret[0] = { "width" : pyr[0].width,
        "height" : pyr[0].height,
        "data" : pyr[0].getContext("2d").getImageData(0, 0, pyr[0].width, pyr[0].height).data };
      var i;
      for (i = 1; i <= interval; i++) {
        pyr[i * 4] = document.createElement("canvas");
        pyr[i * 4].width = Math.floor(pyr[0].width / Math.pow(scale, i));
        pyr[i * 4].height = Math.floor(pyr[0].height / Math.pow(scale, i));
        pyr[i * 4].getContext("2d").drawImage(pyr[0], 0, 0, pyr[0].width, pyr[0].height, 0, 0, pyr[i * 4].width, pyr[i * 4].height);
        ret[i * 4] = { "width" : pyr[i * 4].width,
          "height" : pyr[i * 4].height,
          "data" : pyr[i * 4].getContext("2d").getImageData(0, 0, pyr[i * 4].width, pyr[i * 4].height).data };
      }
      for (i = next; i < scale_upto + next * 2; i++) {
        pyr[i * 4] = document.createElement("canvas");
        pyr[i * 4].width = Math.floor(pyr[i * 4 - next * 4].width / 2);
        pyr[i * 4].height = Math.floor(pyr[i * 4 - next * 4].height / 2);
        pyr[i * 4].getContext("2d").drawImage(pyr[i * 4 - next * 4], 0, 0, pyr[i * 4 - next * 4].width, pyr[i * 4 - next * 4].height, 0, 0, pyr[i * 4].width, pyr[i * 4].height);
        ret[i * 4] = { "width" : pyr[i * 4].width,
          "height" : pyr[i * 4].height,
          "data" : pyr[i * 4].getContext("2d").getImageData(0, 0, pyr[i * 4].width, pyr[i * 4].height).data };
      }
      for (i = next * 2; i < scale_upto + next * 2; i++) {
        pyr[i * 4 + 1] = document.createElement("canvas");
        pyr[i * 4 + 1].width = Math.floor(pyr[i * 4 - next * 4].width / 2);
        pyr[i * 4 + 1].height = Math.floor(pyr[i * 4 - next * 4].height / 2);
        pyr[i * 4 + 1].getContext("2d").drawImage(pyr[i * 4 - next * 4], 1, 0, pyr[i * 4 - next * 4].width - 1, pyr[i * 4 - next * 4].height, 0, 0, pyr[i * 4 + 1].width - 2, pyr[i * 4 + 1].height);
        ret[i * 4 + 1] = { "width" : pyr[i * 4 + 1].width,
          "height" : pyr[i * 4 + 1].height,
          "data" : pyr[i * 4 + 1].getContext("2d").getImageData(0, 0, pyr[i * 4 + 1].width, pyr[i * 4 + 1].height).data };
        pyr[i * 4 + 2] = document.createElement("canvas");
        pyr[i * 4 + 2].width = Math.floor(pyr[i * 4 - next * 4].width / 2);
        pyr[i * 4 + 2].height = Math.floor(pyr[i * 4 - next * 4].height / 2);
        pyr[i * 4 + 2].getContext("2d").drawImage(pyr[i * 4 - next * 4], 0, 1, pyr[i * 4 - next * 4].width, pyr[i * 4 - next * 4].height - 1, 0, 0, pyr[i * 4 + 2].width, pyr[i * 4 + 2].height - 2);
        ret[i * 4 + 2] = { "width" : pyr[i * 4 + 2].width,
          "height" : pyr[i * 4 + 2].height,
          "data" : pyr[i * 4 + 2].getContext("2d").getImageData(0, 0, pyr[i * 4 + 2].width, pyr[i * 4 + 2].height).data };
        pyr[i * 4 + 3] = document.createElement("canvas");
        pyr[i * 4 + 3].width = Math.floor(pyr[i * 4 - next * 4].width / 2);
        pyr[i * 4 + 3].height = Math.floor(pyr[i * 4 - next * 4].height / 2);
        pyr[i * 4 + 3].getContext("2d").drawImage(pyr[i * 4 - next * 4], 1, 1, pyr[i * 4 - next * 4].width - 1, pyr[i * 4 - next * 4].height - 1, 0, 0, pyr[i * 4 + 3].width - 2, pyr[i * 4 + 3].height - 2);
        ret[i * 4 + 3] = { "width" : pyr[i * 4 + 3].width,
          "height" : pyr[i * 4 + 3].height,
          "data" : pyr[i * 4 + 3].getContext("2d").getImageData(0, 0, pyr[i * 4 + 3].width, pyr[i * 4 + 3].height).data };
      }
      return [ret];
    };

    function core(pyr, id, worker_num) {
      var cascade = this.shared.cascade;
      var interval = this.shared.interval;
      var scale = this.shared.scale;
      var next = this.shared.next;
      var scale_upto = this.shared.scale_upto;
      var i, j, k, x, y, q;
      var scale_x = 1, scale_y = 1;
      var dx = [0, 1, 0, 1];
      var dy = [0, 0, 1, 1];
      var seq = [];
      for (i = 0; i < scale_upto; i++) {
        var qw = pyr[i * 4 + next * 8].width - Math.floor(cascade.width / 4);
        var qh = pyr[i * 4 + next * 8].height - Math.floor(cascade.height / 4);
        var step = [pyr[i * 4].width * 4, pyr[i * 4 + next * 4].width * 4, pyr[i * 4 + next * 8].width * 4];
        var paddings = [pyr[i * 4].width * 16 - qw * 16,
          pyr[i * 4 + next * 4].width * 8 - qw * 8,
          pyr[i * 4 + next * 8].width * 4 - qw * 4];
        for (j = 0; j < cascade.stage_classifier.length; j++) {
          var orig_feature = cascade.stage_classifier[j].orig_feature;
          var feature = cascade.stage_classifier[j].feature = new Array(cascade.stage_classifier[j].count);
          for (k = 0; k < cascade.stage_classifier[j].count; k++) {
            feature[k] = {"size" : orig_feature[k].size,
              "px" : new Array(orig_feature[k].size),
              "pz" : new Array(orig_feature[k].size),
              "nx" : new Array(orig_feature[k].size),
              "nz" : new Array(orig_feature[k].size)};
            for (q = 0; q < orig_feature[k].size; q++) {
              feature[k].px[q] = orig_feature[k].px[q] * 4 + orig_feature[k].py[q] * step[orig_feature[k].pz[q]];
              feature[k].pz[q] = orig_feature[k].pz[q];
              feature[k].nx[q] = orig_feature[k].nx[q] * 4 + orig_feature[k].ny[q] * step[orig_feature[k].nz[q]];
              feature[k].nz[q] = orig_feature[k].nz[q];
            }
          }
        }
        for (q = 0; q < 4; q++) {
          var u8 = [pyr[i * 4].data, pyr[i * 4 + next * 4].data, pyr[i * 4 + next * 8 + q].data];
          var u8o = [dx[q] * 8 + dy[q] * pyr[i * 4].width * 8, dx[q] * 4 + dy[q] * pyr[i * 4 + next * 4].width * 4, 0];
          for (y = 0; y < qh; y++) {
            for (x = 0; x < qw; x++) {
              var sum = 0;
              var flag = true;
              for (j = 0; j < cascade.stage_classifier.length; j++) {
                sum = 0;
                var alpha = cascade.stage_classifier[j].alpha;
                var feature = cascade.stage_classifier[j].feature;
                for (k = 0; k < cascade.stage_classifier[j].count; k++) {
                  var feature_k = feature[k];
                  var p, pmin = u8[feature_k.pz[0]][u8o[feature_k.pz[0]] + feature_k.px[0]];
                  var n, nmax = u8[feature_k.nz[0]][u8o[feature_k.nz[0]] + feature_k.nx[0]];
                  if (pmin <= nmax) {
                    sum += alpha[k * 2];
                  } else {
                    var f, shortcut = true;
                    for (f = 0; f < feature_k.size; f++) {
                      if (feature_k.pz[f] >= 0) {
                        p = u8[feature_k.pz[f]][u8o[feature_k.pz[f]] + feature_k.px[f]];
                        if (p < pmin) {
                          if (p <= nmax) {
                            shortcut = false;
                            break;
                          }
                          pmin = p;
                        }
                      }
                      if (feature_k.nz[f] >= 0) {
                        n = u8[feature_k.nz[f]][u8o[feature_k.nz[f]] + feature_k.nx[f]];
                        if (n > nmax) {
                          if (pmin <= n) {
                            shortcut = false;
                            break;
                          }
                          nmax = n;
                        }
                      }
                    }
                    sum += (shortcut) ? alpha[k * 2 + 1] : alpha[k * 2];
                  }
                }
                if (sum < cascade.stage_classifier[j].threshold) {
                  flag = false;
                  break;
                }
              }
              if (flag) {
                seq.push({"x" : (x * 4 + dx[q] * 2) * scale_x,
                  "y" : (y * 4 + dy[q] * 2) * scale_y,
                  "width" : cascade.width * scale_x,
                  "height" : cascade.height * scale_y,
                  "neighbor" : 1,
                  "confidence" : sum});
              }
              u8o[0] += 16;
              u8o[1] += 8;
              u8o[2] += 4;
            }
            u8o[0] += paddings[0];
            u8o[1] += paddings[1];
            u8o[2] += paddings[2];
          }
        }
        scale_x *= scale;
        scale_y *= scale;
      }
      return seq;
    };

    function post(seq) {
      var min_neighbors = this.shared.min_neighbors;
      var cascade = this.shared.cascade;
      var interval = this.shared.interval;
      var scale = this.shared.scale;
      var next = this.shared.next;
      var scale_upto = this.shared.scale_upto;
      var i, j;
      for (i = 0; i < cascade.stage_classifier.length; i++)
        cascade.stage_classifier[i].feature = cascade.stage_classifier[i].orig_feature;
      seq = seq[0];
      if (!(min_neighbors > 0))
        return seq;
      else {
        var result = ccv.array_group(seq, function (r1, r2) {
          var distance = Math.floor(r1.width * 0.25 + 0.5);

          return r2.x <= r1.x + distance &&
            r2.x >= r1.x - distance &&
            r2.y <= r1.y + distance &&
            r2.y >= r1.y - distance &&
            r2.width <= Math.floor(r1.width * 1.5 + 0.5) &&
            Math.floor(r2.width * 1.5 + 0.5) >= r1.width;
        });
        var ncomp = result.cat;
        var idx_seq = result.index;
        var comps = new Array(ncomp + 1);
        for (i = 0; i < comps.length; i++)
          comps[i] = {"neighbors" : 0,
            "x" : 0,
            "y" : 0,
            "width" : 0,
            "height" : 0,
            "confidence" : 0};

        // count number of neighbors
        for(i = 0; i < seq.length; i++)
        {
          var r1 = seq[i];
          var idx = idx_seq[i];

          if (comps[idx].neighbors == 0)
            comps[idx].confidence = r1.confidence;

          ++comps[idx].neighbors;

          comps[idx].x += r1.x;
          comps[idx].y += r1.y;
          comps[idx].width += r1.width;
          comps[idx].height += r1.height;
          comps[idx].confidence = Math.max(comps[idx].confidence, r1.confidence);
        }

        var seq2 = [];
        // calculate average bounding box
        for(i = 0; i < ncomp; i++)
        {
          var n = comps[i].neighbors;
          if (n >= min_neighbors)
            seq2.push({"x" : (comps[i].x * 2 + n) / (2 * n),
              "y" : (comps[i].y * 2 + n) / (2 * n),
              "width" : (comps[i].width * 2 + n) / (2 * n),
              "height" : (comps[i].height * 2 + n) / (2 * n),
              "neighbors" : comps[i].neighbors,
              "confidence" : comps[i].confidence});
        }

        var result_seq = [];
        // filter out small face rectangles inside large face rectangles
        for(i = 0; i < seq2.length; i++)
        {
          var r1 = seq2[i];
          var flag = true;
          for(j = 0; j < seq2.length; j++)
          {
            var r2 = seq2[j];
            var distance = Math.floor(r2.width * 0.25 + 0.5);

            if(i != j &&
              r1.x >= r2.x - distance &&
              r1.y >= r2.y - distance &&
              r1.x + r1.width <= r2.x + r2.width + distance &&
              r1.y + r1.height <= r2.y + r2.height + distance &&
              (r2.neighbors > Math.max(3, r1.neighbors) || r1.neighbors < 3))
            {
              flag = false;
              break;
            }
          }

          if(flag)
            result_seq.push(r1);
        }
        return result_seq;
      }
    };
    return { "pre" : pre, "core" : core, "post" : post };
  })
}

onmessage = function (event) {
  var data = (typeof event.data == "string") ? JSON.parse(event.data) : event.data;
  var scope = { "shared" : data.shared };
  var result = parallable.core[data.name].apply(scope, [data.input, data.id, data.worker]);
  try {
    postMessage(result);
  } catch (e) {
    postMessage(JSON.stringify(result));
  }
}
