C++中标准模板库std::vector的实现

以下实现了C++标准模板库std::vector的部分实现，参考了 cplusplus.

关于C++中标准模板库std::vector的介绍和用法可以参考 https://blog.csdn.net/fengbingchun/article/details/51510916

实现代码vector.hpp内容如下：

#ifndef FBC_STL_VECTOR_HPP_
#define FBC_STL_VECTOR_HPP_

#include 

namespace fbcstd {

template
class vector {
public:
	typedef size_t size_type;
	typedef T value_type;
	typedef T* iterator;
	typedef const T* const_iterator;

	vector();
	vector(size_type n, const value_type& val = value_type());
	vector(const vector& x);
	~vector();

	void reserve(size_type n);
	size_type capacity() const;
	size_type size() const;
	bool empty() const;

	value_type* data();
	const value_type* data() const;

	value_type& at(size_type n);
	const value_type& at(size_type n) const;
	value_type& operator [] (size_type n);
	const value_type& operator [] (size_type n) const;
	vector& operator = (const vector& x);

	void clear();
	value_type& back();
	const value_type& back() const;
	value_type& front();
	const value_type& front() const;

	void push_back(const value_type& val);
	void pop_back();

	void resize(size_type n, value_type val = value_type());

	iterator begin();
	const_iterator begin() const;
	iterator end();
	const_iterator end() const;

private:
	size_type size_ = 0;
	size_type capacity_ = 0; // 2^n
	value_type* buffer_ = nullptr;

}; // class vector

template inline
vector::vector() : size_(0), capacity_(0), buffer_(nullptr)
{
}

template inline
vector::vector(size_type n, const value_type& val)
{
	reserve(n);
	
	size_ = n;
	for (size_t i = 0; i < n; ++i)
		buffer_[i] = val;
}

template inline
vector::vector(const vector& x)
{
	reserve(x.size_);

	size_ = x.size_;
	for (size_t i = 0; i < x.size_; ++i)
		buffer_[i] = x.buffer_[i];
}

template inline
vector::~vector()
{
	if (buffer_)
		delete [] buffer_;
}

template inline
void vector::reserve(size_type n)
{
	if (capacity_ < n) {
		delete [] buffer_;

		capacity_ = 1;
		if (capacity_ < n) {
			capacity_ = 2;
			while (capacity_ < n) {		
				capacity_ *= 2;
			}
		}
		buffer_ = new value_type[capacity_];
	}
}

template inline
size_t vector::capacity() const
{
	return capacity_;
}

template inline
size_t vector::size() const
{
	return size_;
}

template inline
bool vector::empty() const
{
	return size_ == 0 ? true : false;
}

template inline
T* vector::data()
{
	return buffer_;
}

template inline
const T* vector::data() const
{
	return buffer_;
}
	
template inline
T& vector::at(size_type n)
{
	if (size_ <= n) abort();
	return buffer_[n];
}

template inline
const T& vector::at(size_type n) const
{
	if (size_ <= n) abort();
	return buffer_[n];
}

template inline
T& vector::operator [] (size_type n)
{
	if (size_ <= n) abort();
	return buffer_[n];
}

template inline
const T& vector::operator [] (size_type n) const
{
	if (size_ <= n) abort();
	return buffer_[n];
}

template inline
vector& vector::operator = (const vector& x)
{
	reserve(x.size_);

	size_ = x.size_;
	for (size_t i = 0; i < size_; ++i)
		buffer_[i] = x.buffer_[i];

	return *this;
}

template inline
void vector::clear()
{
	size_ = 0;
}

template inline	
T& vector::back()
{
	if (size_ == 0) abort();
	return buffer_[size_-1];
}

template inline
const T& vector::back() const
{
	if (size_ == 0) abort();
	return buffer_[size_-1];
}

template inline	
T& vector::front()
{
	if (size_ == 0) abort();
	return buffer_[0];
}

template inline
const T& vector::front() const
{
	if (size_ == 0) abort();
	return buffer_[0];
}

template inline
void vector::push_back(const value_type& val)
{
	if (size_ >= capacity_) {
		T* tmp = new T[size_];
		for (size_t i = 0; i < size_; ++i)
			tmp[i] = buffer_[i];

		reserve(size_+1);

		for (size_t i = 0; i < size_; ++i)
			buffer_[i] = tmp[i];

		delete [] tmp;
	}

	buffer_[size_] = val;
	size_ += 1;
}

template inline
void vector::pop_back()
{
	if (size_ == 0) abort();
	--size_;
}

template inline
void vector::resize(size_type n, value_type val)
{
	if (size_ < n) {
		if (n > capacity_) {
			T* tmp = new T[size_];
			for (size_t i = 0; i < size_; ++i)
				tmp[i] = buffer_[i];

			reserve(n);

			for (size_t i = 0; i < size_; ++i)
				buffer_[i] = tmp[i];

			delete [] tmp;
		}

		for (size_t i = size_; i < n; ++i)
			buffer_[i] = val;
	}

	size_ = n;
}

template inline
T* vector::begin()
{
	return buffer_;
}

template inline
const T* vector::begin() const
{
	return buffer_;
}

template inline
T* vector::end()
{
	return buffer_ + size_;
}

template inline
const T* vector::end() const
{
	return buffer_ + size_;
}

template static inline
bool operator == (const vector& lhs, const vector& rhs)
{
	if (lhs.size() != rhs.size())
		return false;

	for (size_t i = 0; i < lhs.size(); ++i)	{
		if (lhs[i] != rhs[i])
			return false;
	}

	return true;
}

template static inline
bool operator != (const vector& lhs, const vector& rhs)
{
	return !(lhs == rhs);
}

template static inline
bool operator < (const vector& lhs, const vector& rhs)
{
	bool flag = true;
	if (lhs.size() == rhs.size()) {
		if (lhs == rhs) {
			flag = false;
		} else {
			for (size_t i = 0; i < lhs.size(); ++i) {
				if (lhs[i] > rhs[i]) {
					flag = false;
					break;
				}
			}
		}
	} else if (lhs.size() < rhs.size()) {
		vector vec(lhs.size());
		for (size_t i = 0; i < lhs.size(); ++i)
			vec[i] = rhs[i];

		if (lhs == vec) {
			flag = true;
		} else {
			for (size_t i = 0; i < lhs.size(); ++i) {
				if (lhs[i] > rhs[i]) {
					flag = false;
					break;
				}
			}
		}
	} else {
		vector vec(rhs.size());
		for (size_t i = 0; i < rhs.size(); ++i)
			vec[i] = lhs[i];

		if (vec == rhs) {
			flag = false;
		} else {
			for (size_t i = 0; i < rhs.size(); ++i) {
				if (lhs[i] > rhs[i]) {
					flag = false;
					break;
				}
			}
		}
	}

	return flag;
}

template static inline
bool operator <= (const vector& lhs, const vector& rhs)
{
	return !(rhs < lhs);
}

template static inline
bool operator > (const vector& lhs, const vector& rhs)
{
	return (rhs < lhs);
}

template static inline
bool operator >= (const vector& lhs, const vector& rhs)
{
	return !(lhs < rhs);
}

} // namespace fbcstd

#endif // FBC_STL_VECTOR_HPP_ 

 测试代码test_vector.cpp内容如下：

#include 
#include "vector.hpp"
#include "string.hpp"

#define std fbcstd

int main()
{

{ // constructor, capacity, size, empty, data
	std::vector vec1;
	fprintf(stdout, "vec1 size: %d, capacity: %d, empty: %d\n", vec1.size(), vec1.capacity(), vec1.empty());
	std::vector vec2(1);
	fprintf(stdout, "vec2 size: %d, capacity: %d, empty: %d\n", vec2.size(), vec2.capacity(), vec2.empty());
	fprintf(stdout, "vec2 data: %d\n", *(vec2.data()));
	std::vector vec3(5, "test vector");
	fprintf(stdout, "vec3 size: %d, capacity: %d, empty: %d\n", vec3.size(), vec3.capacity(), vec3.empty());
	const std::string* p1 = vec3.data();
	fprintf(stdout, "vec3 data: \n");
	for (size_t i = 0; i < vec3.size(); ++i) {
		fprintf(stdout, " %s,", (*p1).c_str());
		p1++;
	}
	std::vector vec4(vec3);
	fprintf(stdout, "\nvec4 size: %d, capacity: %d, empty: %d\n", vec4.size(), vec4.capacity(), vec4.empty());
	std::string* p2 = vec4.data();
	fprintf(stdout, "vec4 data: \n");
	for (size_t i = 0; i < vec4.size(); ++i)
		*p2++ = "TEST VECTOR";
	const std::string* p3 = vec4.data();
	for (size_t i = 0; i < vec4.size(); ++i) {
		fprintf(stdout, " %s,", (*p3).c_str());
		p3++;
	}
	fprintf(stdout, "\n");
}

{ // at, [], =, clear
	std::vector vec1(2);
	vec1.at(0) = "test";
	vec1.at(1) = "vector";
	fprintf(stdout, "vec1: %s, %s\n", vec1.at(0).c_str(), vec1.at(1).c_str());
	vec1[0] = "TEST";
	vec1[1] = "VECTOR";
	fprintf(stdout, "vec1: %s, %s\n", vec1[0].c_str(), vec1[1].c_str());
	
	std::vector vec2;
	vec2 = vec1;
	fprintf(stdout, "vec2 size: %d, %s, %s\n", vec2.size(), vec2[0].c_str(), vec2[1].c_str());
	vec2.clear();
	fprintf(stdout, "vec2 size: %d\n", vec2.size());
}

{ // back, front
	std::vector vec(2, 1000);
	fprintf(stdout, "value: %d\n", vec.back());
	vec.back() = -1000;
	fprintf(stdout, "value: %d\n", vec.back());
	fprintf(stdout, "value: %d\n", vec.front());
	vec.front() = -1000;
	fprintf(stdout, "value: %d\n", vec.front());
}

{ // push_back, pop_back
	std::vector vec;
	for (int i = 0; i < 10; ++i)
		vec.push_back((i+1)*10);
	fprintf(stdout, "vec: size: %d, capacity: %d\nvalue: ", vec.size(), vec.capacity());
	for (int i = 0; i < vec.size(); ++i)
		fprintf(stdout, " %d,", vec[i]);

	for (int i = 0; i < 5; ++i)
		vec.pop_back();
	fprintf(stdout, "\nvec: size: %d, capacity: %d\nvalue: ", vec.size(), vec.capacity());
	for (int i = 0; i < vec.size(); ++i)
		fprintf(stdout, " %d,", vec[i]);
	fprintf(stdout, "\n");	
}

{ // resize
	std::vector myvector;

  	for (int i = 1; i < 10; ++i)
		myvector.push_back(i);

	myvector.resize(5);
	myvector.resize(8,100);
	myvector.resize(12);

	fprintf(stdout, "myvector contains:");
	for (size_t i = 0; i < myvector.size(); ++i)
		fprintf(stdout, " %d,", myvector[i]);
	fprintf(stdout, "\n");
}

{ // begin, end
	std::vector myvector;
	for (int i = 1; i <= 5; ++i)
		myvector.push_back(i);

	fprintf(stdout, "myvector contains:");
	for (std::vector::iterator it = myvector.begin() ; it != myvector.end(); ++it)
		fprintf(stdout, " %d,", *it);
	fprintf(stdout, "\n");
	for (std::vector::const_iterator it = myvector.begin() ; it != myvector.end(); ++it)
		fprintf(stdout, " %d,", *it);
	fprintf(stdout, "\n");
}

{ // compare operator
	std::vector foo (3,100);
	std::vector bar (2,200);

	if (foo == bar) fprintf(stdout, "foo and bar are equal\n");
	if (foo != bar) fprintf(stdout, "foo and bar are not equal\n");
	if (foo < bar) fprintf(stdout, "foo is less than bar\n");
	if (foo > bar) fprintf(stdout, "foo is greater than bar\n");
	if (foo <= bar)	fprintf(stdout, "foo is less than or equal to bar\n");
	if (foo >=bar)	fprintf(stdout, "foo is greater than or equal to bar\n");
}

	return 0;
}

CMakeLists.txt内容如下：

PROJECT(Samples_STL_Implementation)
CMAKE_MINIMUM_REQUIRED(VERSION 3.0)

SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -Wall -O2 -std=c11")
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}  -g -Wall -O2 -std=c++11")

INCLUDE_DIRECTORIES(${PROJECT_SOURCE_DIR}/src)
MESSAGE(STATUS "project source dir: ${PROJECT_SOURCE_DIR}")

FILE(GLOB tests ${PROJECT_SOURCE_DIR}/test/*.cpp)

FOREACH (test ${tests})
	STRING(REGEX MATCH "[^/]+$" test_file ${test})
	STRING(REPLACE ".cpp" "" test_basename ${test_file})
	ADD_EXECUTABLE(${test_basename} ${test})
	TARGET_LINK_LIBRARIES(${test_basename} pthread)
ENDFOREACH()

build.sh脚本内容如下：

#! /bin/bash

real_path=$(realpath $0)
dir_name=`dirname "${real_path}"`
echo "real_path: ${real_path}, dir_name: ${dir_name}"

new_dir_name=${dir_name}/build
mkdir -p ${new_dir_name}
cd ${new_dir_name}
cmake ..
make

cd -

编译及执行操作步骤：将终端定位到Samples_STL_Implementation目录下，执行：$ ./build.sh , 然后再执行$ ./build/test_vector即可。

GitHub： https://github.com/fengbingchun/Linux_Code_Test