Stl 哈希表基础头文件
哈希表基础头文件，比较简短，相对繁忙的DarkSpy也有时间写注释的说，hehe[code]
/*
* Copyright (c) 1996-1998
* 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.
*
*
* 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.
*
*/
/* NOTE: This is an internal header file, included by other STL headers.
* You should not attempt to use it directly.
*/
#ifndef __SGI_STL_HASH_FUN_H
#define __SGI_STL_HASH_FUN_H
#include <stddef.h>
__STL_BEGIN_NAMESPACE
template <class _Key> struct hash { }; //空模板类
inline size_t __stl_hash_string(const char* __s)
{
unsigned long __h = 0;
for ( ; *__s; ++__s)
__h = 5*__h + *__s;
return size_t(__h); //返回指针长度
}
//__STL_TEMPLATE_NULL 在 stl_config.h 定义，为模板特例的 define
//__STL_TEMPLATE_NULL = template <>
__STL_TEMPLATE_NULL struct hash<char*>
{
size_t operator()(const char* __s) const { return __stl_hash_string(__s); }
//重载 ()，返回 __stl_hash_string 函数计算的一个指针长度的 unsigned
};
//相当于 template <> struct hash<char *> 模板类特例化
//比起 template struct<char *> hash; 直接实例化的话，目标代码可以缩小好多倍。效率也很高
__STL_TEMPLATE_NULL struct hash<const char*> //特例 const char *
{
size_t operator()(const char* __s) const { return __stl_hash_string(__s); }
};
__STL_TEMPLATE_NULL struct hash<char> { //特例 char
size_t operator()(char __x) const { return __x; } //返回一个字符
};
__STL_TEMPLATE_NULL struct hash<unsigned char> { //特例 unsigned char
size_t operator()(unsigned char __x) const { return __x; }
//返回 unsigned char
};
__STL_TEMPLATE_NULL struct hash<signed char> { //特例 signed char
size_t operator()(unsigned char __x) const { return __x; }
//返回的也是 unsingned char 一个字符
};
__STL_TEMPLATE_NULL struct hash<short> { //特例 shor
size_t operator()(short __x) const { return __x; }
//返回 short int
};
__STL_TEMPLATE_NULL struct hash<unsigned short> { //特例 unsigned short
size_t operator()(unsigned short __x) const { return __x; }
//返回 unsigned short
};
__STL_TEMPLATE_NULL struct hash<int> { //特例 int
size_t operator()(int __x) const { return __x; }
//返回 int
};
__STL_TEMPLATE_NULL struct hash<unsigned int> { //特例 unsigned int
size_t operator()(unsigned int __x) const { return __x; }
//返回unsigned int
};
__STL_TEMPLATE_NULL struct hash<long> { //特例 long
size_t operator()(long __x) const { return __x; }
//返回long
};
__STL_TEMPLATE_NULL struct hash<unsigned long> {//特例unsigned long
size_t operator()(unsigned long __x) const { return __x; }
//返回 unsigned long
};
__STL_END_NAMESPACE
#endif /* __SGI_STL_HASH_FUN_H */
// Local Variables:
// mode:C++
// End:
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