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+/////////////////////////////////////////////////////////////////////////////
+// Copyright (c) Electronic Arts Inc. All rights reserved.
+/////////////////////////////////////////////////////////////////////////////
+
+
+#if defined(_MSC_VER)
+ //#pragma warning(disable: 4267) // 'argument' : conversion from 'size_t' to 'uint32_t', possible loss of data.
+#endif
+
+
+#include "EASTLTest.h"
+#include <EASTL/numeric_limits.h>
+#include <EASTL/set.h>
+#include <EASTL/random.h>
+
+
+struct GeneratorUint8
+{
+ uint8_t mValue;
+ GeneratorUint8() : mValue(0) {}
+ uint8_t operator()(){ return mValue++; } // This is a pretty bad random number generator, but works for our tests.
+};
+
+struct GeneratorUint16
+{
+ uint16_t mValue;
+ GeneratorUint16() : mValue(0) {}
+ uint16_t operator()(){ return mValue++; }
+};
+
+struct GeneratorUint32
+{
+ uint32_t mValue;
+ GeneratorUint32() : mValue(0) {}
+ uint32_t operator()(){ return mValue++; }
+};
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+// TestRandom
+//
+int TestRandom()
+{
+ int nErrorCount = 0;
+
+ {
+ // template<class IntType = int>
+ // class uniform_int_distribution
+
+ // The C++11 Standard defines a number of formal Generators, such as std::mersenne_twister_engine,
+ // linear_congruential_engine, discard_block_engine, etc.
+
+ using namespace eastl;
+
+ {
+ eastl::uniform_int_distribution<uint8_t> uid(1, 6);
+ GeneratorUint8 g;
+
+ for(uint32_t i = 0; i < UINT8_MAX; i += 1)
+ {
+ uint8_t value = uid(g);
+ EATEST_VERIFY((value >= 1) && (value <= 6));
+ // To do: Validate the randomness of the value.
+ }
+
+ eastl::uniform_int_distribution<uint8_t> uid2(1, 6);
+ EATEST_VERIFY(uid == uid2);
+ }
+
+ {
+ eastl::uniform_int_distribution<uint16_t> uid(1, 6);
+ GeneratorUint16 g;
+
+ for(uint32_t i = 0; i < (UINT16_MAX - (UINT16_MAX / 50)); i += (UINT16_MAX / 50))
+ {
+ uint16_t value = uid(g);
+ EATEST_VERIFY((value >= 1) && (value <= 6));
+ // To do: Validate the randomness of the value.
+ }
+
+ eastl::uniform_int_distribution<uint16_t> uid2(1, 6);
+ EATEST_VERIFY(uid == uid2);
+ }
+
+ {
+ eastl::uniform_int_distribution<uint32_t> uid(1, 6);
+ GeneratorUint32 g;
+
+ for(uint32_t i = 0; i < (UINT32_MAX - (UINT32_MAX / 500)); i += (UINT32_MAX / 500))
+ {
+ uint32_t value = uid(g);
+ EATEST_VERIFY((value >= 1) && (value <= 6));
+ // To do: Validate the randomness of the value.
+ }
+
+ eastl::uniform_int_distribution<uint32_t> uid2(1, 6);
+ EATEST_VERIFY(uid == uid2);
+ }
+ }
+
+
+
+ /// Example usage:
+ /// eastl_size_t Rand(eastl_size_t n) { return (eastl_size_t)(rand() % n); } // Note: The C rand function is poor and slow.
+ /// pointer_to_unary_function<eastl_size_t, eastl_size_t> randInstance(Rand);
+ /// random_shuffle(pArrayBegin, pArrayEnd, randInstance);
+ ///
+ /// Example usage:
+ /// struct Rand{ eastl_size_t operator()(eastl_size_t n) { return (eastl_size_t)(rand() % n); } }; // Note: The C rand function is poor and slow.
+ /// Rand randInstance;
+ /// random_shuffle(pArrayBegin, pArrayEnd, randInstance);
+
+
+ {
+ // void random_shuffle(RandomAccessIterator first, RandomAccessIterator last, RandomNumberGenerator& rng)
+ using namespace eastl;
+
+ EASTLTest_Rand rng(EA::UnitTest::GetRandSeed());
+ int intArray[] = { 3, 2, 6, 5, 4, 1 };
+
+ random_shuffle(intArray, intArray + 0, rng);
+ EATEST_VERIFY(VerifySequence(intArray, intArray + 6, int(), "random_shuffle", 3, 2, 6, 5, 4, 1, -1));
+
+ random_shuffle(intArray, intArray + (sizeof(intArray) / sizeof(intArray[0])), rng);
+ bool changed = false;
+ for(int i = 0; (i < 5) && !changed; i++)
+ {
+ changed = (intArray[0] != 3) || (intArray[1] != 2) || (intArray[2] != 6) ||
+ (intArray[3] != 5) || (intArray[4] != 4) || (intArray[5] != 1);
+ }
+ EATEST_VERIFY(changed);
+
+ // Test of possible bug report by user John Chin.
+ // The report is that shuffling an ordered array 0, 1, 2, 3, 4 ... results in duplicates, such as 5, 2, 2, 4 ...
+ eastl::vector<eastl_size_t> rngArray;
+
+ for(eastl_size_t i = 0; i < 200; ++i)
+ rngArray.push_back(i);
+
+ random_shuffle(rngArray.begin(), rngArray.end(), rng);
+ EATEST_VERIFY(rngArray.validate());
+
+ eastl::set<eastl_size_t> intSet;
+
+ for(eastl_size_t s = 0, sEnd = rngArray.size(); s < sEnd; ++s)
+ intSet.insert(rngArray[s]);
+
+ // If the shuffled array is unique, then a set of its values should be the same size as the array.
+ EATEST_VERIFY(intSet.size() == rngArray.size());
+ }
+
+
+ return nErrorCount;
+}
+
+
+
+
+
+
+
+
+
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+