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