extreme refactoring

[chaz/yoink] / src / Moof / Random.cc

diff --git a/src/Moof/Random.cc b/src/Moof/Random.cc
new file mode 100644 (file)
index 0000000..a881008
--- /dev/null
+++ b/src/Moof/Random.cc
@@ -0,0 +1,118 @@
+
+/*******************************************************************************
+
+ Copyright (c) 2009, Charles McGarvey
+ All rights reserved.
+ 
+ Redistribution   and   use  in  source  and  binary  forms,  with  or  without
+ modification, are permitted provided that the following conditions are met:
+ 
+   * Redistributions  of  source  code  must retain the above copyright notice,
+     this list of conditions and the following disclaimer.
+   * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
+
+*******************************************************************************/
+
+#include <climits>             // ULONG_MAX
+#include <cmath>               // log
+#include <cstdlib>             // srand, rand, RAND_MAX
+#include <ctime>               // time
+
+#include "Random.hh"
+
+
+namespace Mf {
+
+
+unsigned setSeed(unsigned theSeed)
+{
+       srand(theSeed);
+       return theSeed;
+}
+
+unsigned setSeed()
+{
+       return setSeed(time(0));
+}
+
+
+template <typename T>
+T getRandom()
+{
+       const  float ln2 = 0.693147;
+       static const unsigned bitsPerPiece = std::log(float(RAND_MAX)) / ln2;
+       static const unsigned sizeOfType = sizeof(T) * 8;
+       static const unsigned pieces = sizeOfType / bitsPerPiece +
+                                                                ((sizeOfType % bitsPerPiece) ? 1 : 0);
+
+       T bits = 0;
+
+       // we need to call rand() multiple times if it won't provide enough random
+       // bits to fill the size of the given type
+       for (unsigned i = 0; i < pieces; i++)
+       {
+               long piece = rand();
+               bits |= piece << (i * bitsPerPiece);
+       }
+
+       return bits;
+}
+
+
+template <>
+bool getRandom<bool>()
+{
+       return rand() % 2;
+}
+
+template <typename T>
+T getRandom(T lower, T upper)
+{
+       unsigned short randInt = getRandom<unsigned int>();
+       return lower + T(randInt % (upper - lower + 1));
+}
+
+template <>
+float getRandom(float lower, float upper)
+{
+       unsigned long randInt = getRandom<unsigned long>();
+       return (float(randInt) / float(ULONG_MAX)) * (upper - lower) + lower;
+}
+
+template <>
+double getRandom(double lower, double upper)
+{
+       unsigned long long randInt = getRandom<unsigned long long>();
+       return (double(randInt) / double(ULLONG_MAX)) * (upper - lower) + lower;
+}
+
+template <>
+float getRandom()
+{
+       return getRandom<float>(0.0, 1.0);
+}
+
+template <>
+double getRandom()
+{
+       return getRandom<double>(0.0, 1.0);
+}
+
+
+}; // namespace Mf
+
+/** vim: set ts=4 sw=4 tw=80: *************************************************/
+