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[pom.git] / integral_array.h

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+
+//////////////////////////////////////////////////////////////////////////////////
+// This program is free software: you can redistribute it and/or modify         //
+// it under the terms of the version 3 of the GNU General Public License        //
+// as published by the Free Software Foundation.                                //
+//                                                                              //
+// This program is distributed in the hope that it will be useful, but          //
+// WITHOUT ANY WARRANTY; without even the implied warranty of                   //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             //
+// General Public License for more details.                                     //
+//                                                                              //
+// You should have received a copy of the GNU General Public License            //
+// along with this program. If not, see <http://www.gnu.org/licenses/>.         //
+//                                                                              //
+// Written by Francois Fleuret                                                  //
+// (C) Ecole Polytechnique Federale de Lausanne                                 //
+// Contact <pom@epfl.ch> for comments & bug reports                             //
+//////////////////////////////////////////////////////////////////////////////////
+
+#ifndef INTEGRAL_ARRAY_H
+#define INTEGRAL_ARRAY_H
+
+#include <iostream>
+
+using namespace std;
+
+#include "array.h"
+
+template <class T>
+class IntegralArray: public Array<T> {
+public:
+
+  void compute(const Array<T> *m) {
+    T *v = Array<T>::content, *w = m->Array<T>::content;
+    for(int x = 0; x < Array<T>::height; x++) *(v++) = 0;
+
+    register T sl;
+    for(int y = 1; y < Array<T>::width; y++) {
+      sl = 0; *(v++) = 0;
+      for(int x = 0; x < Array<T>::height - 1; x++) {
+        sl += *(w++);
+        *(v++) = sl + *(v - Array<T>::height);
+      }
+    }
+  }
+
+  IntegralArray(int w, int h) : Array<T>(w+1, h+1) { }
+
+  IntegralArray(const Array<T> &m) : Array<T>(m->get_width() + 1, m->get_height() + 1) {
+    compute(m);
+  }
+
+  // Integral on xmin <= x < xmax, ymin <= y < ymax
+  // Thus, xmax and ymax can go up to m->width+1 and m->height+1 respectively
+
+  inline T integral(int xmin, int ymin, int xmax, int ymax) const {
+    ASSERT(xmin <= xmax && ymin <= ymax, "Inconsistent bounds for integral");
+    ASSERT(xmin >= 0 && xmax < Array<T>::width &&
+           ymin >= 0 && ymax < Array<T>::height, "Index out of bounds in Array::operator () const");
+    return Array<T>::heads[xmax][ymax] + Array<T>::heads[xmin][ymin]
+      - Array<T>::heads[xmax][ymin] - Array<T>::heads[xmin][ymax];
+  }
+};
+
+#endif