| // Copyright 2017 The Abseil Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "absl/strings/internal/resize_uninitialized.h" |
| |
| #include "gtest/gtest.h" |
| |
| namespace { |
| |
| int resize_call_count = 0; |
| |
| // A mock string class whose only purpose is to track how many times its |
| // resize() method has been called. |
| struct resizable_string { |
| size_t size() const { return 0; } |
| size_t capacity() const { return 0; } |
| char& operator[](size_t) { |
| static char c = '\0'; |
| return c; |
| } |
| void resize(size_t) { resize_call_count += 1; } |
| void reserve(size_t) {} |
| }; |
| |
| int resize_default_init_call_count = 0; |
| |
| // A mock string class whose only purpose is to track how many times its |
| // resize() and __resize_default_init() methods have been called. |
| struct resize_default_init_string { |
| size_t size() const { return 0; } |
| size_t capacity() const { return 0; } |
| char& operator[](size_t) { |
| static char c = '\0'; |
| return c; |
| } |
| void resize(size_t) { resize_call_count += 1; } |
| void __resize_default_init(size_t) { resize_default_init_call_count += 1; } |
| void reserve(size_t) {} |
| }; |
| |
| TEST(ResizeUninit, WithAndWithout) { |
| resize_call_count = 0; |
| resize_default_init_call_count = 0; |
| { |
| resizable_string rs; |
| |
| EXPECT_EQ(resize_call_count, 0); |
| EXPECT_EQ(resize_default_init_call_count, 0); |
| EXPECT_FALSE( |
| absl::strings_internal::STLStringSupportsNontrashingResize(&rs)); |
| EXPECT_EQ(resize_call_count, 0); |
| EXPECT_EQ(resize_default_init_call_count, 0); |
| absl::strings_internal::STLStringResizeUninitialized(&rs, 237); |
| EXPECT_EQ(resize_call_count, 1); |
| EXPECT_EQ(resize_default_init_call_count, 0); |
| absl::strings_internal::STLStringResizeUninitializedAmortized(&rs, 1000); |
| EXPECT_EQ(resize_call_count, 2); |
| EXPECT_EQ(resize_default_init_call_count, 0); |
| } |
| |
| resize_call_count = 0; |
| resize_default_init_call_count = 0; |
| { |
| resize_default_init_string rus; |
| |
| EXPECT_EQ(resize_call_count, 0); |
| EXPECT_EQ(resize_default_init_call_count, 0); |
| EXPECT_TRUE( |
| absl::strings_internal::STLStringSupportsNontrashingResize(&rus)); |
| EXPECT_EQ(resize_call_count, 0); |
| EXPECT_EQ(resize_default_init_call_count, 0); |
| absl::strings_internal::STLStringResizeUninitialized(&rus, 237); |
| EXPECT_EQ(resize_call_count, 0); |
| EXPECT_EQ(resize_default_init_call_count, 1); |
| absl::strings_internal::STLStringResizeUninitializedAmortized(&rus, 1000); |
| EXPECT_EQ(resize_call_count, 0); |
| EXPECT_EQ(resize_default_init_call_count, 2); |
| } |
| } |
| |
| TEST(ResizeUninit, Amortized) { |
| std::string str; |
| size_t prev_cap = str.capacity(); |
| int cap_increase_count = 0; |
| for (int i = 0; i < 1000; ++i) { |
| absl::strings_internal::STLStringResizeUninitializedAmortized(&str, i); |
| size_t new_cap = str.capacity(); |
| if (new_cap > prev_cap) ++cap_increase_count; |
| prev_cap = new_cap; |
| } |
| EXPECT_LT(cap_increase_count, 50); |
| } |
| |
| } // namespace |