зеркало из https://github.com/mozilla/gecko-dev.git
147 строки
3.2 KiB
C++
147 строки
3.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "RollingNumber.h"
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#include "mozilla/Assertions.h"
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#include "mozilla/TypeTraits.h"
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#include <cstdint>
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#include <gtest/gtest.h>
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using RN8 = mozilla::RollingNumber<uint8_t>;
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TEST(RollingNumber, Value)
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{
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// Value type should reflect template argument.
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static_assert(mozilla::IsSame<RN8::ValueType, uint8_t>::value, "");
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// Default init to 0.
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const RN8 n;
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// Access through Value().
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EXPECT_EQ(0, n.Value());
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// Conversion constructor.
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RN8 n42{ 42 };
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EXPECT_EQ(42, n42.Value());
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// Copy Constructor.
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RN8 n42Copied{ n42 };
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EXPECT_EQ(42, n42Copied.Value());
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// Assignment construction.
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RN8 n42Assigned = n42;
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EXPECT_EQ(42, n42Assigned.Value());
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// Assignment.
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n42 = n;
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EXPECT_EQ(0, n42.Value());
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}
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TEST(RollingNumber, Operations)
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{
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RN8 n;
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EXPECT_EQ(0, n.Value());
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RN8 nPreInc = ++n;
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EXPECT_EQ(1, n.Value());
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EXPECT_EQ(1, nPreInc.Value());
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RN8 nPostInc = n++;
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EXPECT_EQ(2, n.Value());
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EXPECT_EQ(1, nPostInc.Value());
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RN8 nPreDec = --n;
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EXPECT_EQ(1, n.Value());
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EXPECT_EQ(1, nPreDec.Value());
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RN8 nPostDec = n--;
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EXPECT_EQ(0, n.Value());
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EXPECT_EQ(1, nPostDec.Value());
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RN8 nPlus = n + 10;
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EXPECT_EQ(0, n.Value());
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EXPECT_EQ(10, nPlus.Value());
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n += 20;
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EXPECT_EQ(20, n.Value());
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RN8 nMinus = n - 2;
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EXPECT_EQ(20, n.Value());
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EXPECT_EQ(18, nMinus.Value());
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n -= 5;
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EXPECT_EQ(15, n.Value());
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uint8_t diff = nMinus - n;
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EXPECT_EQ(3, diff);
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// Overflows.
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n = RN8(0);
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EXPECT_EQ(0, n.Value());
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n--;
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EXPECT_EQ(255, n.Value());
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n++;
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EXPECT_EQ(0, n.Value());
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n -= 10;
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EXPECT_EQ(246, n.Value());
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n += 20;
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EXPECT_EQ(10, n.Value());
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}
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TEST(RollingNumber, Comparisons)
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{
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uint8_t i = 0;
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do {
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RN8 n{ i };
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EXPECT_EQ(i, n.Value());
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EXPECT_TRUE(n == n);
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EXPECT_FALSE(n != n);
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EXPECT_FALSE(n < n);
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EXPECT_TRUE(n <= n);
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EXPECT_FALSE(n > n);
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EXPECT_TRUE(n >= n);
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RN8 same = n;
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EXPECT_TRUE(n == same);
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EXPECT_FALSE(n != same);
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EXPECT_FALSE(n < same);
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EXPECT_TRUE(n <= same);
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EXPECT_FALSE(n > same);
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EXPECT_TRUE(n >= same);
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#ifdef DEBUG
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// In debug builds, we are only allowed a quarter of the type range.
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const uint8_t maxDiff = 255 / 4;
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#else
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// In non-debug builds, we can go half-way up or down the type range, and
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// still conserve the expected ordering.
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const uint8_t maxDiff = 255 / 2;
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#endif
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for (uint8_t add = 1; add <= maxDiff; ++add) {
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RN8 bigger = n + add;
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EXPECT_FALSE(n == bigger);
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EXPECT_TRUE(n != bigger);
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EXPECT_TRUE(n < bigger);
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EXPECT_TRUE(n <= bigger);
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EXPECT_FALSE(n > bigger);
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EXPECT_FALSE(n >= bigger);
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}
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for (uint8_t sub = 1; sub <= maxDiff; ++sub) {
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RN8 smaller = n - sub;
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EXPECT_FALSE(n == smaller);
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EXPECT_TRUE(n != smaller);
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EXPECT_FALSE(n < smaller);
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EXPECT_FALSE(n <= smaller);
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EXPECT_TRUE(n > smaller);
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EXPECT_TRUE(n >= smaller);
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}
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++i;
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} while (i != 0);
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}
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