diff options
| -rw-r--r-- | absl/algorithm/container.h | 33 | ||||
| -rw-r--r-- | absl/algorithm/container_test.cc | 23 |
2 files changed, 47 insertions, 9 deletions
diff --git a/absl/algorithm/container.h b/absl/algorithm/container.h index 2457d78b..5c033571 100644 --- a/absl/algorithm/container.h +++ b/absl/algorithm/container.h @@ -539,12 +539,20 @@ BidirectionalIterator c_move_backward(C&& src, BidirectionalIterator dest) { // c_swap_ranges() // // Container-based version of the <algorithm> `std::swap_ranges()` function to -// swap a container's elements with another container's elements. +// swap a container's elements with another container's elements. Swaps the +// first N elements of `c1` and `c2`, where N = min(size(c1), size(c2)). template <typename C1, typename C2> container_algorithm_internal::ContainerIter<C2> c_swap_ranges(C1& c1, C2& c2) { - return std::swap_ranges(container_algorithm_internal::c_begin(c1), - container_algorithm_internal::c_end(c1), - container_algorithm_internal::c_begin(c2)); + auto first1 = container_algorithm_internal::c_begin(c1); + auto last1 = container_algorithm_internal::c_end(c1); + auto first2 = container_algorithm_internal::c_begin(c2); + auto last2 = container_algorithm_internal::c_end(c2); + + using std::swap; + for (; first1 != last1 && first2 != last2; ++first1, (void)++first2) { + swap(*first1, *first2); + } + return first2; } // c_transform() @@ -562,16 +570,23 @@ OutputIterator c_transform(const InputSequence& input, OutputIterator output, } // Overload of c_transform() for performing a transformation using a binary -// predicate. +// predicate. Applies `binary_op` to the first N elements of `c1` and `c2`, +// where N = min(size(c1), size(c2)). template <typename InputSequence1, typename InputSequence2, typename OutputIterator, typename BinaryOp> OutputIterator c_transform(const InputSequence1& input1, const InputSequence2& input2, OutputIterator output, BinaryOp&& binary_op) { - return std::transform(container_algorithm_internal::c_begin(input1), - container_algorithm_internal::c_end(input1), - container_algorithm_internal::c_begin(input2), output, - std::forward<BinaryOp>(binary_op)); + auto first1 = container_algorithm_internal::c_begin(input1); + auto last1 = container_algorithm_internal::c_end(input1); + auto first2 = container_algorithm_internal::c_begin(input2); + auto last2 = container_algorithm_internal::c_end(input2); + for (; first1 != last1 && first2 != last2; + ++first1, (void)++first2, ++output) { + *output = binary_op(*first1, *first2); + } + + return output; } // c_replace() diff --git a/absl/algorithm/container_test.cc b/absl/algorithm/container_test.cc index 0a4abe94..3abf5cea 100644 --- a/absl/algorithm/container_test.cc +++ b/absl/algorithm/container_test.cc @@ -676,6 +676,15 @@ TEST(MutatingTest, SwapRanges) { absl::c_swap_ranges(odds, evens); EXPECT_THAT(odds, ElementsAre(1, 3, 5)); EXPECT_THAT(evens, ElementsAre(2, 4, 6)); + + odds.pop_back(); + absl::c_swap_ranges(odds, evens); + EXPECT_THAT(odds, ElementsAre(2, 4)); + EXPECT_THAT(evens, ElementsAre(1, 3, 6)); + + absl::c_swap_ranges(evens, odds); + EXPECT_THAT(odds, ElementsAre(1, 3)); + EXPECT_THAT(evens, ElementsAre(2, 4, 6)); } TEST_F(NonMutatingTest, Transform) { @@ -690,6 +699,20 @@ TEST_F(NonMutatingTest, Transform) { EXPECT_EQ(std::vector<int>({1, 5, 4}), z); *end = 7; EXPECT_EQ(std::vector<int>({1, 5, 4, 7}), z); + + z.clear(); + y.pop_back(); + end = absl::c_transform(x, y, std::back_inserter(z), std::plus<int>()); + EXPECT_EQ(std::vector<int>({1, 5}), z); + *end = 7; + EXPECT_EQ(std::vector<int>({1, 5, 7}), z); + + z.clear(); + std::swap(x, y); + end = absl::c_transform(x, y, std::back_inserter(z), std::plus<int>()); + EXPECT_EQ(std::vector<int>({1, 5}), z); + *end = 7; + EXPECT_EQ(std::vector<int>({1, 5, 7}), z); } TEST(MutatingTest, Replace) { |