return adl_begin(RangeOrContainer) == adl_end(RangeOrContainer);
}
-/// Returns true of the given range only contains a single element.
-template <typename ContainerTy> bool hasSingleElement(ContainerTy &&c) {
- auto it = std::begin(c), e = std::end(c);
- return it != e && std::next(it) == e;
+/// Returns true if the given container only contains a single element.
+template <typename ContainerTy> bool hasSingleElement(ContainerTy &&C) {
+ auto B = std::begin(C), E = std::end(C);
+ return B != E && std::next(B) == E;
}
/// Return a range covering \p RangeOrContainer with the first N elements
return false; // Too few.
N -= ShouldBeCounted(*Begin);
}
- return Begin == End;
+ for (; Begin != End; ++Begin)
+ if (ShouldBeCounted(*Begin))
+ return false; // Too many.
+ return true;
}
/// Return true if the sequence [Begin, End) has N or more items. Runs in O(N)
/// time. Not meant for use with random-access iterators.
-/// Can optionally take a predicate to filter lazily some items.
+/// Can optionally take a predicate to lazily filter some items.
template<typename IterTy,
typename Pred = bool (*)(const decltype(*std::declval<IterTy>()) &)>
bool hasNItemsOrMore(
return true;
}
+/// Returns true if the sequence [Begin, End) has N or less items. Can
+/// optionally take a predicate to lazily filter some items.
+template <typename IterTy,
+ typename Pred = bool (*)(const decltype(*std::declval<IterTy>()) &)>
+bool hasNItemsOrLess(
+ IterTy &&Begin, IterTy &&End, unsigned N,
+ Pred &&ShouldBeCounted = [](const decltype(*std::declval<IterTy>()) &) {
+ return true;
+ }) {
+ assert(N != std::numeric_limits<unsigned>::max());
+ return !hasNItemsOrMore(Begin, End, N + 1, ShouldBeCounted);
+}
+
+/// Returns true if the given container has exactly N items
+template <typename ContainerTy> bool hasNItems(ContainerTy &&C, unsigned N) {
+ return hasNItems(std::begin(C), std::end(C), N);
+}
+
+/// Returns true if the given container has N or more items
+template <typename ContainerTy>
+bool hasNItemsOrMore(ContainerTy &&C, unsigned N) {
+ return hasNItemsOrMore(std::begin(C), std::end(C), N);
+}
+
+/// Returns true if the given container has N or less items
+template <typename ContainerTy>
+bool hasNItemsOrLess(ContainerTy &&C, unsigned N) {
+ return hasNItemsOrLess(std::begin(C), std::end(C), N);
+}
+
/// Returns a raw pointer that represents the same address as the argument.
///
/// This implementation can be removed once we move to C++20 where it's defined
EXPECT_EQ(V.end(), partition_point(V, [](unsigned X) { return X < 50; }));
}
+TEST(STLExtrasTest, hasSingleElement) {
+ const std::vector<int> V0 = {}, V1 = {1}, V2 = {1, 2};
+ const std::vector<int> V10(10);
+
+ EXPECT_EQ(hasSingleElement(V0), false);
+ EXPECT_EQ(hasSingleElement(V1), true);
+ EXPECT_EQ(hasSingleElement(V2), false);
+ EXPECT_EQ(hasSingleElement(V10), false);
+}
+
+TEST(STLExtrasTest, hasNItems) {
+ const std::list<int> V0 = {}, V1 = {1}, V2 = {1, 2};
+ const std::list<int> V3 = {1, 3, 5};
+
+ EXPECT_TRUE(hasNItems(V0, 0));
+ EXPECT_FALSE(hasNItems(V0, 2));
+ EXPECT_TRUE(hasNItems(V1, 1));
+ EXPECT_FALSE(hasNItems(V1, 2));
+
+ EXPECT_TRUE(hasNItems(V3.begin(), V3.end(), 3, [](int x) { return x < 10; }));
+ EXPECT_TRUE(hasNItems(V3.begin(), V3.end(), 0, [](int x) { return x > 10; }));
+ EXPECT_TRUE(hasNItems(V3.begin(), V3.end(), 2, [](int x) { return x < 5; }));
+}
+
+TEST(STLExtras, hasNItemsOrMore) {
+ const std::list<int> V0 = {}, V1 = {1}, V2 = {1, 2};
+ const std::list<int> V3 = {1, 3, 5};
+
+ EXPECT_TRUE(hasNItemsOrMore(V1, 1));
+ EXPECT_FALSE(hasNItemsOrMore(V1, 2));
+
+ EXPECT_TRUE(hasNItemsOrMore(V2, 1));
+ EXPECT_TRUE(hasNItemsOrMore(V2, 2));
+ EXPECT_FALSE(hasNItemsOrMore(V2, 3));
+
+ EXPECT_TRUE(hasNItemsOrMore(V3, 3));
+ EXPECT_FALSE(hasNItemsOrMore(V3, 4));
+
+ EXPECT_TRUE(
+ hasNItemsOrMore(V3.begin(), V3.end(), 3, [](int x) { return x < 10; }));
+ EXPECT_FALSE(
+ hasNItemsOrMore(V3.begin(), V3.end(), 3, [](int x) { return x > 10; }));
+ EXPECT_TRUE(
+ hasNItemsOrMore(V3.begin(), V3.end(), 2, [](int x) { return x < 5; }));
+}
+
+TEST(STLExtras, hasNItemsOrLess) {
+ const std::list<int> V0 = {}, V1 = {1}, V2 = {1, 2};
+ const std::list<int> V3 = {1, 3, 5};
+
+ EXPECT_TRUE(hasNItemsOrLess(V0, 0));
+ EXPECT_TRUE(hasNItemsOrLess(V0, 1));
+ EXPECT_TRUE(hasNItemsOrLess(V0, 2));
+
+ EXPECT_FALSE(hasNItemsOrLess(V1, 0));
+ EXPECT_TRUE(hasNItemsOrLess(V1, 1));
+ EXPECT_TRUE(hasNItemsOrLess(V1, 2));
+
+ EXPECT_FALSE(hasNItemsOrLess(V2, 0));
+ EXPECT_FALSE(hasNItemsOrLess(V2, 1));
+ EXPECT_TRUE(hasNItemsOrLess(V2, 2));
+ EXPECT_TRUE(hasNItemsOrLess(V2, 3));
+
+ EXPECT_FALSE(hasNItemsOrLess(V3, 0));
+ EXPECT_FALSE(hasNItemsOrLess(V3, 1));
+ EXPECT_FALSE(hasNItemsOrLess(V3, 2));
+ EXPECT_TRUE(hasNItemsOrLess(V3, 3));
+ EXPECT_TRUE(hasNItemsOrLess(V3, 4));
+
+ EXPECT_TRUE(
+ hasNItemsOrLess(V3.begin(), V3.end(), 1, [](int x) { return x == 1; }));
+ EXPECT_TRUE(
+ hasNItemsOrLess(V3.begin(), V3.end(), 2, [](int x) { return x < 5; }));
+ EXPECT_TRUE(
+ hasNItemsOrLess(V3.begin(), V3.end(), 5, [](int x) { return x < 5; }));
+ EXPECT_FALSE(
+ hasNItemsOrLess(V3.begin(), V3.end(), 2, [](int x) { return x < 10; }));
+}
} // namespace