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<font color="#0000ff">// Copyright (c) 1999-2002 David Muse</font>
<font color="#0000ff">// See the COPYING file for more information.</font>
<font color="#a020f0">#ifndef RUDIMENTS_RANDOMNUMBER_H</font>
<font color="#a020f0">#define RUDIMENTS_RANDOMNUMBER_H</font>
<font color="#a020f0">#include </font><font color="#ff00ff"><rudiments/private/randomnumberincludes.h></font>
<font color="#0000ff">// The randomnumber class provides methods for generating and scaling </font>
<font color="#0000ff">// random numbers.</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// A common practice for generating random number sequences is to seed the</font>
<font color="#0000ff">// first call to generateNumber() with the number of seconds since 1970 (see</font>
<font color="#0000ff">// the datetime class) and seed each successive call with the previously</font>
<font color="#0000ff">// generated number.</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// Superfluous background:</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// Random numbers are actually just a highly divergent series. There is</font>
<font color="#0000ff">// no such thing as true randomness. Using the above described methodology, </font>
<font color="#0000ff">// if there is only one running process generating random numbers, successive </font>
<font color="#0000ff">// calls to generateNumber() will never return the same value until all </font>
<font color="#0000ff">// numbers between 0 and 2^32 have been returned. At that point, the entire </font>
<font color="#0000ff">// sequence will repeat. Calls to generateScaledNumber() may return the</font>
<font color="#0000ff">// same value before all numbers in the range have been returned because</font>
<font color="#0000ff">// it scales the result of generateNumber() which operates on a larger range.</font>
<font color="#a020f0">#ifdef RUDIMENTS_NAMESPACE</font>
<font color="#2e8b57"><b>namespace</b></font> rudiments {
<font color="#a020f0">#endif</font>
<font color="#2e8b57"><b>class</b></font> randomnumber {
<font color="#a52a2a"><b>public</b></font>:
<font color="#2e8b57"><b>static</b></font> <font color="#2e8b57"><b>int</b></font> generateNumber(<font color="#2e8b57"><b>int</b></font> seed);
<font color="#0000ff">// Generates a random number between 0 and 2^32, based</font>
<font color="#0000ff">// on seed, and returns it. </font>
<font color="#0000ff">//</font>
<font color="#0000ff">// It is ok to use the result of this method as the </font>
<font color="#0000ff">// seed for the next number.</font>
<font color="#2e8b57"><b>static</b></font> <font color="#2e8b57"><b>int</b></font> generateScaledNumber(<font color="#2e8b57"><b>int</b></font> seed,
<font color="#2e8b57"><b>int</b></font> lower, <font color="#2e8b57"><b>int</b></font> upper);
<font color="#0000ff">// Generates a random number between 0 and 2^32, based</font>
<font color="#0000ff">// on seed, scales that value to be between</font>
<font color="#0000ff">// lower and upper and returns it.</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// It is NOT ok to use the result of this method as </font>
<font color="#0000ff">// the seed for the next number.</font>
<font color="#2e8b57"><b>static</b></font> <font color="#2e8b57"><b>int</b></font> scaleNumber(<font color="#2e8b57"><b>int</b></font> number, <font color="#2e8b57"><b>int</b></font> lower, <font color="#2e8b57"><b>int</b></font> upper);
<font color="#0000ff">// Scales number to be between lower and upper and </font>
<font color="#0000ff">// returns it.</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// It is NOT ok to use the result of this method as </font>
<font color="#0000ff">// the seed for the next number.</font>
<font color="#2e8b57"><b>static</b></font> <font color="#2e8b57"><b>int</b></font> getRandMax();
<font color="#0000ff">// Operating systems can generate random numbers</font>
<font color="#0000ff">// between 0 and RAND_MAX.</font>
<font color="#0000ff">// This method returns RAND_MAX.</font>
<font color="#0000ff">// </font>
<font color="#0000ff">// RAND_MAX is usually 2^31-1 on 32 bit machines</font>
<font color="#0000ff">// but there are exceptions where it is 2^15-1 or</font>
<font color="#0000ff">// 2^32-1.</font>
<font color="#2e8b57"><b>static</b></font> <font color="#2e8b57"><b>bool</b></font> needsMutex();
<font color="#0000ff">// If your system doesn't support rand_r() then this</font>
<font color="#0000ff">// class needs a mutex to assure thread safety.</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// This method returns true if this class needs a mutex</font>
<font color="#0000ff">// to operate safely in a threaded environment and false</font>
<font color="#0000ff">// otherwise.</font>
<font color="#2e8b57"><b>static</b></font> <font color="#2e8b57"><b>void</b></font> setMutex(mutex *mtx);
<font color="#0000ff">// Allows you to supply a mutex is the class needs it.</font>
<font color="#0000ff">// If your application is not multithreaded, then</font>
<font color="#0000ff">// there is no need to supply a mutex.</font>
};
<font color="#a020f0">#ifdef RUDIMENTS_NAMESPACE</font>
}
<font color="#a020f0">#endif</font>
<font color="#a020f0">#endif</font>
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