近来看了看《STL源码剖析》中的空间配置器，尝试着读了一下，觉得模板还是强大的，同时对于allocator的函数有了进一步的认识。
#if 0
#include<memory>
//alloctor 的必要接口
allocator::valuetype
allocator::pointer
allocator::const_pointer
allocator::reference
allocator::const_reference
allocator::size_type
allocator::difference_type
allocator::rebind
allocator::allocactor() //default constructor
allocator::allocator(const allocator&) //copy constructor
template <class U>allocator::allocator(const allocator<U>&) //泛化的 copy constructor
allocator::~allocator//default constructor
pointer allocator::address(reference x) const//返回某个对象的地址。a.address(x) const 等同于&x
const_pointer allocator::address(const_reference x) const//返回某个const 对象的地址
pointer allocator::allocate(size_type n,const void* = 0) //分配空间，存n个对象。第二个参数是提示，实现上可能会利用它来增进区域性，可忽略
void allocator::deallocate(point p,size_type n) //归还当前分配的空间
size_type allocator::max_size() const //返回可成功分配的最大量
void allocator::construct(point p,const T& x) //等同于new
void allocator::destroy(point p) //等同于p->~T()#endif//设计一个简单的空间配置器 allocator
//file:steem_alloc.h 自己的头文件
#ifndef _STEEMALLOC_
#define _STEEMALLOC_#include<new>
#include<cstddef>
#include<cstdlib>
#include<climits>
#include<iostream>namespace steem
{template <class T>inline T* _allocate(ptrdiff_t size, T*){set_new_handler(0);T* tmp = (T*)(::operator new((size_t)(size * sizeof(T))));if (tmp == 0){cerr << "out of memory" << endl;exit(1);}return tmp;}template <class T>inline void _deallocate(T* buffer){::operator delete(buffer);}template <class T1,class T2>inline void _construct(T1* p, const T2& value){new(p) T1(value);}template <class T>inline void _destroy(T* ptr){ptr->~T();}template <class T>class allocator{public:typedef T value_type;typedef T* pointer;typedef const T* const_pointer;typedef T& reference;typedef const T& const_reference;typedef ptrdiff_t defference_type;//rebind allocator of type Utemplate <class U>struct rebind{typedef alloactor<U> other;};pointer allocate(size_type n, const void* hint = 0){return _allocate(((difference_type)n, (pointer)0));}void deallocate(point p, size_type n) { _deallocate(p); }void construct(pointer p, const T& value){_construct(p, value);}void destroy(point p) { _destroy(p); }pointer address(reference x) { return (pointer)&x; }const_pointer const_address(const_reference x){return (const_pointer)&x;}size_type max_size() const{return size_type(UINT_MAX / sizeof(T));}};}#endif //STEMMALLOC#include<vector>
#include<iostream>
using namespace std;//main 函数中
int main_t1()
{int ia[5] = { 0,1,2,3,4 };unsigned int i;vector<int, steem::allocator<int> > iv(ia, ia + 5);for (i = 0; i < iv.size(); i++){cout << iv[i] << ' ';}cout << endl;return 0;
}
