/*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*
* Copyright (c) 1996,1997
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*/
/* NOTE: This is an internal header file, included by other STL headers.
* You should not attempt to use it directly.
*/
#ifndef __SGI_STL_INTERNAL_UNINITIALIZED_H
#define __SGI_STL_INTERNAL_UNINITIALIZED_H
__STL_BEGIN_NAMESPACE
// uninitialized_copy :
// 注意了解模板编程的思路。
// 利用 __VALUE_TYPE 取出型别定义
// 再次利用 __type_traits 取得类型特征
// 据类型特征直接转到特例化的模板函数。
// 优点：
// 避免在运行时判断数值的型别，在编译期就可以确定数值的最优处理方案。
// Valid if copy construction is equivalent to assignment, and if the
// destructor is trivial.
template <class _InputIter, class _ForwardIter>
inline _ForwardIter
__uninitialized_copy_aux(_InputIter __first, _InputIter __last,
_ForwardIter __result,
__true_type) // __true_type 是型别，不是变量
{
// 是常规类型，可以不一个个执行拷贝构造函数
return copy(__first, __last, __result);
}
template <class _InputIter, class _ForwardIter>
_ForwardIter
__uninitialized_copy_aux(_InputIter __first, _InputIter __last,
_ForwardIter __result,
__false_type)
{
// 这是非标准的型别，我们需要执行它的拷贝构造函式来构建
_ForwardIter __cur = __result;
__STL_TRY {
for ( ; __first != __last; ++__first, ++__cur)
// 逐个构造数据， 这里用的是 _Construct 的 place new 访问方式。
_Construct(&*__cur, *__first);
return __cur;
}
// 在失败时，还需要清除构建的对象，这是由 STL 标准控制
__STL_UNWIND(_Destroy(__result, __cur));
}
// 临时构建的模板函式，用来区分纯量型型别
template <class _InputIter, class _ForwardIter, class _Tp>
inline _ForwardIter
__uninitialized_copy(_InputIter __first, _InputIter __last,
_ForwardIter __result, _Tp*)
{
// 利用 type_traits 分列出数据类型，是否是 POD
// 什么是？
// POD 意指 Plain Old Data，也就是纯量型別（scalar types）或传统的 C struct 型別。
// PDO 具有更高效率的构造方式，即直接从内存复制，而不需要拷贝构造函数。
typedef typename __type_traits<_Tp>::is_POD_type _Is_POD;
// 按照是否构造函数无关紧要，来拷贝数据
return __uninitialized_copy_aux(__first, __last, __result, _Is_POD());
}
// 通用式，它根据 __VALUE_TYPE 取数值类型
template <class _InputIter, class _ForwardIter>
inline _ForwardIter
uninitialized_copy(_InputIter __first, _InputIter __last,
_ForwardIter __result)
{
return __uninitialized_copy(__first, __last, __result,
__VALUE_TYPE(__result));
}
// 这是特例化的，征对 char 和 wchar_t 的特例
inline char* uninitialized_copy(const char* __first, const char* __last,
char* __result) {
memmove(__result, __first, __last - __first);
return __result + (__last - __first);
}
inline wchar_t*
uninitialized_copy(const wchar_t* __first, const wchar_t* __last,
wchar_t* __result)
{
memmove(__result, __first, sizeof(wchar_t) * (__last - __first));
return __result + (__last - __first);
}
//uninitialized_copy<__VALUE_TYPE>
// ----> __uninitialized_copy<__type_traits> : is_POD_type
//
// ----> __uninitialized_copy_aux<__false_type>
// __uninitialized_copy_aux<__false_type>
//
//uninitialized_copy<char>
//uninitialized_copy<wchar_t>
// uninitialized_copy_n (not part of the C++ standard)
template <class _InputIter, class _Size, class _ForwardIter>
pair<_InputIter, _ForwardIter>
__uninitialized_copy_n(_InputIter __first, _Size __count,
_ForwardIter __result,
input_iterator_tag)
{
_ForwardIter __cur = __result;
__STL_TRY {
for ( ; __count > 0 ; --__count, ++__first, ++__cur)
_Construct(&*__cur, *__first);
return pair<_InputIter, _ForwardIter>(__first, __cur);
}
__STL_UNWIND(_Destroy(__result, __cur));
}
template <class _RandomAccessIter, class _Size, class _ForwardIter>
inline pair<_RandomAccessIter, _ForwardIter>
__uninitialized_copy_n(_RandomAccessIter __first, _Size __count,
_ForwardIter __result,
random_access_iterator_tag) {
_RandomAccessIter __last = __first + __count;
return pair<_RandomAccessIter, _ForwardIter>(
__last,
uninitialized_copy(__first, __last, __result));
}
template <class _InputIter, class _Size, class _ForwardIter>
inline pair<_InputIter, _ForwardIter>
__uninitialized_copy_n(_InputIter __first, _Size __count,
_ForwardIter __result) {
return __uninitialized_copy_n(__first, __count, __result,
__ITERATOR_CATEGORY(__first));
}
template <class _InputIter, class _Size, class _ForwardIter>
inline pair<_InputIter, _ForwardIter>
uninitialized_copy_n(_InputIter __first, _Size __count,
_ForwardIter __result) {
return __uninitialized_copy_n(__first, __count, __result,
__ITERATOR_CATEGORY(__first));
}
// uninitialized_fill :
// 这里是把一个集合的数据 [__first, __last) ，按 __x 值进行填充
// 这里的做法和 uninitialized_copy 一致
// Valid if copy construction is equivalent to assignment, and if the
// destructor is trivial.
template <class _ForwardIter, class _Tp>
inline void
__uninitialized_fill_aux(_ForwardIter __first, _ForwardIter __last,
const _Tp& __x, __true_type)
{
fill(__first, __last, __x);
}
template <class _ForwardIter, class _Tp>
void
__uninitialized_fill_aux(_ForwardIter __first, _ForwardIter __last,
const _Tp& __x, __false_type)
{
_ForwardIter __cur = __first;
__STL_TRY {
for ( ; __cur != __last; ++__cur)
_Construct(&*__cur, __x); // place new ，你懂的！ __x 是常量的引用传递
}
__STL_UNWIND(_Destroy(__first, __cur)); // 出事了？ STL 标准要求删除所有已构建的对象实例
}
template <class _ForwardIter, class _Tp, class _Tp1>
inline void __uninitialized_fill(_ForwardIter __first,
_ForwardIter __last, const _Tp& __x, _Tp1*)
{
typedef typename __type_traits<_Tp1>::is_POD_type _Is_POD;
__uninitialized_fill_aux(__first, __last, __x, _Is_POD());
}
template <class _ForwardIter, class _Tp>
inline void uninitialized_fill(_ForwardIter __first,
_ForwardIter __last,
const _Tp& __x)
{
__uninitialized_fill(__first, __last, __x, __VALUE_TYPE(__first));
}
// uninitialized_fill_n :
// 这个模板填充一个集合，其成员从 [ __first, __first + n )
// 内容统一设置成 __x
// 实作技法同上
// Valid if copy construction is equivalent to assignment, and if the
// destructor is trivial.
template <class _ForwardIter, class _Size, class _Tp>
inline _ForwardIter
__uninitialized_fill_n_aux(_ForwardIter __first, _Size __n,
const _Tp& __x, __true_type)
{
return fill_n(__first, __n, __x);
}
template <class _ForwardIter, class _Size, class _Tp>
_ForwardIter
__uninitialized_fill_n_aux(_ForwardIter __first, _Size __n,
const _Tp& __x, __false_type)
{
_ForwardIter __cur = __first;
__STL_TRY {
for ( ; __n > 0; --__n, ++__cur)
_Construct(&*__cur, __x);
return __cur;
}
__STL_UNWIND(_Destroy(__first, __cur));
}
template <class _ForwardIter, class _Size, class _Tp, class _Tp1>
inline _ForwardIter
__uninitialized_fill_n(_ForwardIter __first, _Size __n, const _Tp& __x, _Tp1*)
{
typedef typename __type_traits<_Tp1>::is_POD_type _Is_POD;
return __uninitialized_fill_n_aux(__first, __n, __x, _Is_POD());
}
template <class _ForwardIter, class _Size, class _Tp>
inline _ForwardIter
uninitialized_fill_n(_ForwardIter __first, _Size __n, const _Tp& __x)
{
return __uninitialized_fill_n(__first, __n, __x, __VALUE_TYPE(__first));
}
// Extensions: __uninitialized_copy_copy, __uninitialized_copy_fill,
// __uninitialized_fill_copy.
// 这个函数用来把 2 个 区间内的数据，拷贝到一个里边去。
// 它首先拷贝 [first1, last1) 部分，
// 再接着把 [first2, last2) 拷贝到了接下来的缓冲区
// __uninitialized_copy_copy
// Copies [first1, last1) into [result, result + (last1 - first1)), and
// copies [first2, last2) into
// 原文这应该是写了错误的注释： [result, result + (last1 - first1) + (last2 - first2)).
// 正确来说，它应该是 [result + (last1 - first1) , result + (last1 - first1) + (last2 - first2)).
// 或者 [ __mid , __mid + (last2 - first2)).
template <class _InputIter1, class _InputIter2, class _ForwardIter>
inline _ForwardIter
__uninitialized_copy_copy(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2, _InputIter2 __last2,
_ForwardIter __result)
{
_ForwardIter __mid = uninitialized_copy(__first1, __last1, __result);
__STL_TRY {
return uninitialized_copy(__first2, __last2, __mid);
}
__STL_UNWIND(_Destroy(__result, __mid));
}
// __uninitialized_fill_copy
// Fills [result, mid) with x, and copies [first, last) into
// [mid, mid + (last - first)).
template <class _ForwardIter, class _Tp, class _InputIter>
inline _ForwardIter
__uninitialized_fill_copy(_ForwardIter __result, _ForwardIter __mid,
const _Tp& __x,
_InputIter __first, _InputIter __last)
{
uninitialized_fill(__result, __mid, __x);
__STL_TRY {
return uninitialized_copy(__first, __last, __mid);
}
__STL_UNWIND(_Destroy(__result, __mid));
}
// __uninitialized_copy_fill
// Copies [first1, last1) into [first2, first2 + (last1 - first1)), and
// fills [first2 + (last1 - first1), last2) with x.
template <class _InputIter, class _ForwardIter, class _Tp>
inline void
__uninitialized_copy_fill(_InputIter __first1, _InputIter __last1,
_ForwardIter __first2, _ForwardIter __last2,
const _Tp& __x)
{
_ForwardIter __mid2 = uninitialized_copy(__first1, __last1, __first2);
__STL_TRY {
uninitialized_fill(__mid2, __last2, __x);
}
__STL_UNWIND(_Destroy(__first2, __mid2));
}
__STL_END_NAMESPACE
#endif /* __SGI_STL_INTERNAL_UNINITIALIZED_H */
// Local Variables:
// mode:C++
// End: