| 1 | //===-- Unittests for rand ------------------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "src/stdlib/rand.h" |
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| 10 | #include "src/stdlib/srand.h" |
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| 11 | #include "test/UnitTest/Test.h" |
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| 12 | |
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| 13 | #include <stddef.h> |
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| 14 | |
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| 15 | TEST(LlvmLibcRandTest, UnsetSeed) { |
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| 16 | static int vals[1000]; |
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| 17 | |
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| 18 | for (size_t i = 0; i < 1000; ++i) { |
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| 19 | int val = LIBC_NAMESPACE::rand(); |
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| 20 | ASSERT_GE(val, 0); |
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| 21 | ASSERT_LE(val, RAND_MAX); |
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| 22 | vals[i] = val; |
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| 23 | } |
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| 24 | |
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| 25 | // The C standard specifies that if 'srand' is never called it should behave |
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| 26 | // as if 'srand' was called with a value of 1. If we seed the value with 1 we |
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| 27 | // should get the same sequence as the unseeded version. |
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| 28 | LIBC_NAMESPACE::srand(1); |
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| 29 | for (size_t i = 0; i < 1000; ++i) |
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| 30 | ASSERT_EQ(LIBC_NAMESPACE::rand(), vals[i]); |
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| 31 | } |
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| 32 | |
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| 33 | TEST(LlvmLibcRandTest, SetSeed) { |
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| 34 | const unsigned int SEED = 12344321; |
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| 35 | LIBC_NAMESPACE::srand(SEED); |
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| 36 | const size_t NUM_RESULTS = 10; |
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| 37 | int results[NUM_RESULTS]; |
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| 38 | for (size_t i = 0; i < NUM_RESULTS; ++i) { |
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| 39 | results[i] = LIBC_NAMESPACE::rand(); |
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| 40 | ASSERT_GE(results[i], 0); |
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| 41 | ASSERT_LE(results[i], RAND_MAX); |
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| 42 | } |
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| 43 | |
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| 44 | // If the seed is set to the same value, it should give the same sequence. |
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| 45 | LIBC_NAMESPACE::srand(SEED); |
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| 46 | |
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| 47 | for (size_t i = 0; i < NUM_RESULTS; ++i) { |
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| 48 | int val = LIBC_NAMESPACE::rand(); |
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| 49 | EXPECT_EQ(results[i], val); |
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| 50 | } |
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| 51 | } |
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| 52 | |
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