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// 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;
int append_call_count = 0;
// A mock string class whose only purpose is to track how many times its
// resize()/append() methods have been called.
struct resizable_string {
using value_type = char;
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 append(size_t, value_type) { append_call_count += 1; }
void reserve(size_t) {}
resizable_string& erase(size_t = 0, size_t = 0) { return *this; }
};
int resize_default_init_call_count = 0;
int append_default_init_call_count = 0;
// A mock string class whose only purpose is to track how many times its
// resize()/__resize_default_init()/append()/__append_default_init() methods
// have been called.
struct 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 __append_default_init(size_t) { append_default_init_call_count += 1; }
void reserve(size_t) {}
default_init_string& erase(size_t = 0, size_t = 0) { return *this; }
};
TEST(ResizeUninit, WithAndWithout) {
resize_call_count = 0;
append_call_count = 0;
resize_default_init_call_count = 0;
append_default_init_call_count = 0;
{
resizable_string rs;
EXPECT_EQ(resize_call_count, 0);
EXPECT_EQ(append_call_count, 0);
EXPECT_EQ(resize_default_init_call_count, 0);
EXPECT_EQ(append_default_init_call_count, 0);
EXPECT_FALSE(
absl::strings_internal::STLStringSupportsNontrashingResize(&rs));
EXPECT_EQ(resize_call_count, 0);
EXPECT_EQ(append_call_count, 0);
EXPECT_EQ(resize_default_init_call_count, 0);
EXPECT_EQ(append_default_init_call_count, 0);
absl::strings_internal::STLStringResizeUninitialized(&rs, 237);
EXPECT_EQ(resize_call_count, 1);
EXPECT_EQ(append_call_count, 0);
EXPECT_EQ(resize_default_init_call_count, 0);
EXPECT_EQ(append_default_init_call_count, 0);
absl::strings_internal::STLStringResizeUninitializedAmortized(&rs, 1000);
EXPECT_EQ(resize_call_count, 1);
EXPECT_EQ(append_call_count, 1);
EXPECT_EQ(resize_default_init_call_count, 0);
EXPECT_EQ(append_default_init_call_count, 0);
}
resize_call_count = 0;
append_call_count = 0;
resize_default_init_call_count = 0;
append_default_init_call_count = 0;
{
default_init_string rus;
EXPECT_EQ(resize_call_count, 0);
EXPECT_EQ(append_call_count, 0);
EXPECT_EQ(resize_default_init_call_count, 0);
EXPECT_EQ(append_default_init_call_count, 0);
EXPECT_TRUE(
absl::strings_internal::STLStringSupportsNontrashingResize(&rus));
EXPECT_EQ(resize_call_count, 0);
EXPECT_EQ(append_call_count, 0);
EXPECT_EQ(resize_default_init_call_count, 0);
EXPECT_EQ(append_default_init_call_count, 0);
absl::strings_internal::STLStringResizeUninitialized(&rus, 237);
EXPECT_EQ(resize_call_count, 0);
EXPECT_EQ(append_call_count, 0);
EXPECT_EQ(resize_default_init_call_count, 1);
EXPECT_EQ(append_default_init_call_count, 0);
absl::strings_internal::STLStringResizeUninitializedAmortized(&rus, 1000);
EXPECT_EQ(resize_call_count, 0);
EXPECT_EQ(append_call_count, 0);
EXPECT_EQ(resize_default_init_call_count, 1);
EXPECT_EQ(append_default_init_call_count, 1);
}
}
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
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