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+/***********************************************************************
+ * Software License Agreement (BSD License)
+ *
+ * Copyright 2008-2009 Marius Muja (mariusm@cs.ubc.ca). All rights reserved.
+ * Copyright 2008-2009 David G. Lowe (lowe@cs.ubc.ca). All rights reserved.
+ *
+ * THE BSD LICENSE
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *************************************************************************/
+
+#ifndef OPENCV_FLANN_RANDOM_H
+#define OPENCV_FLANN_RANDOM_H
+
+#include <algorithm>
+#include <cstdlib>
+#include <vector>
+
+#include "general.h"
+
+namespace cvflann
+{
+
+/**
+ * Seeds the random number generator
+ * @param seed Random seed
+ */
+inline void seed_random(unsigned int seed)
+{
+ srand(seed);
+}
+
+/*
+ * Generates a random double value.
+ */
+/**
+ * Generates a random double value.
+ * @param high Upper limit
+ * @param low Lower limit
+ * @return Random double value
+ */
+inline double rand_double(double high = 1.0, double low = 0)
+{
+ return low + ((high-low) * (std::rand() / (RAND_MAX + 1.0)));
+}
+
+/**
+ * Generates a random integer value.
+ * @param high Upper limit
+ * @param low Lower limit
+ * @return Random integer value
+ */
+inline int rand_int(int high = RAND_MAX, int low = 0)
+{
+ return low + (int) ( double(high-low) * (std::rand() / (RAND_MAX + 1.0)));
+}
+
+/**
+ * Random number generator that returns a distinct number from
+ * the [0,n) interval each time.
+ */
+class UniqueRandom
+{
+ std::vector<int> vals_;
+ int size_;
+ int counter_;
+
+public:
+ /**
+ * Constructor.
+ * @param n Size of the interval from which to generate
+ * @return
+ */
+ UniqueRandom(int n)
+ {
+ init(n);
+ }
+
+ /**
+ * Initializes the number generator.
+ * @param n the size of the interval from which to generate random numbers.
+ */
+ void init(int n)
+ {
+ // create and initialize an array of size n
+ vals_.resize(n);
+ size_ = n;
+ for (int i = 0; i < size_; ++i) vals_[i] = i;
+
+ // shuffle the elements in the array
+ std::random_shuffle(vals_.begin(), vals_.end());
+
+ counter_ = 0;
+ }
+
+ /**
+ * Return a distinct random integer in greater or equal to 0 and less
+ * than 'n' on each call. It should be called maximum 'n' times.
+ * Returns: a random integer
+ */
+ int next()
+ {
+ if (counter_ == size_) {
+ return -1;
+ }
+ else {
+ return vals_[counter_++];
+ }
+ }
+};
+
+}
+
+#endif //OPENCV_FLANN_RANDOM_H