c++ 头文件<cwchar>中常见函数的实现！！！

c++ 头文件<cwchar>中常见函数的实现！！！

废话不多说了，代码说明了一切！！！（代码封装于名字空间mystd中）

#pragma once 
#ifndef MYSTD_CWCHAR_H
#define MYSTD_CWCHAR_H
#include<cassert> // assert 
#include<cstddef> //std::size_t

// 在vs2012中调试通过,封装于名字空间mystd中
//文件建议命名为"cwchar.h"（与标准库并不冲突）

#define MYSTD_BEGIN namespace mystd {
#define MYSTD_END   }




#ifdef __cplusplus

MYSTD_BEGIN
	typedef std::size_t size_type;
	typedef wchar_t char_type;
	inline size_type wcslen(const char_type* wcs)
	{
     assert(wcs != 0);
	 size_type count = 0;
	 while(*wcs++)
		 ++count;
	 return count;
	}
	inline char_type* wcscat(char_type* destination,const char_type *source)
	{
		assert(destination != 0 && source != 0);
		char_type *des = destination + mystd::wcslen(destination);
		while(*des++ = *source++);
		return destination;
	}
	inline char_type* wcsncat(char_type* destination,const char_type *source,size_type num)
	{
		assert(destination != 0 && source != 0);
		char_type *des = destination + mystd::wcslen(destination);
		while(num-- && *source)
			*des++ = *source++;
		*des = 0; 
		return destination;
	}
	inline char_type* wcscpy(char_type *destination,const char_type *source)
	{
		assert(destination != 0 && source != 0);
		char_type *des = destination;
		while(*des++ = *source++);
		return destination;
	}
	inline char_type* wcsncpy(char_type *destination,const char_type *source,size_type num)
	{
		assert(destination != 0 && source != 0);
		char_type *des = destination;
		while(num--)
			*des++ = *source++; 
		return destination; // 可能不包含null wide character 
	}
	inline int wcscmp(const char_type *wcs1,const char_type *wcs2)
	{
		assert(wcs1 != 0 && wcs2 != 0);
		while(*wcs1 && *wcs1 == *wcs2)
			++wcs1, ++wcs2;
		return *wcs1 - *wcs2;
	}
	inline int wcsncmp(const char_type *wcs1,const char_type *wcs2,size_type num)
	{
		assert(wcs1 != 0 && wcs2 != 0);
		while(num-- && *wcs1 && *wcs1 == *wcs2)
			++wcs1, ++wcs2;
		if(num == size_type(-1))  // 包含了num == 0的情况
			return 0;
		else
			return *wcs1 - *wcs2;
	}
	inline const char_type* wmemchr(const char_type* pointer,char_type val,size_type num)
	{
    	assert(pointer != 0);
		char_type *ptr = (char_type*)pointer;
	    for(size_type i = 0; i < num; ++i)
		{
			if(*ptr == val)
				break;
			++ptr;
		}
		return ptr;
	}
    inline char_type* wmemchr(char_type* pointer,char_type val,size_type num)
	{
		assert(pointer != 0);
		return (char_type*)wmemchr((const char_type*)pointer,val,num);
	}
	inline int wmemcmp(const char_type *ptr_1,const char_type *ptr_2,size_type num)
	{
		assert(ptr_1 != 0 && ptr_2 != 0);
		while(num-- && *ptr_1 == *ptr_2)
			++ptr_1, ++ptr_2;
		if(num == size_type(-1))
			return 0;
		else
			return *ptr_1 - *ptr_2;
	}
	inline char_type* wmemset(char_type *pointer,char_type val,size_type num)
	{
		assert(pointer != 0);
		char_type *ptr = pointer;
		while(num--)
			*ptr++ = val;
		return pointer;
	}
	inline char_type* wmemmove(char_type *destination,const char_type *source,size_type num)
	{
		assert(destination != 0 && source != 0); 
		if(destination == source || num == 0)
			return destination;
		char_type *des = (char_type*)destination;  
		const char_type *src = (char_type*)source;  
		if(des < src || des >= src + num)  
		{
				while(num--)
					*des++ = *src++;
				return destination;
		}
		des += num;
		src += num;
		while(num--) // 倒序复制
			*--des = *--src;
		return destination;
	}
	inline char_type* wmemcpy(char_type *destination,const char_type *source,size_type num)
	{
		assert(destination != 0 && source != 0);
		return mystd::wmemmove(destination,source,num);
	}
	inline bool w_is_inside(const char_type *wcs,char_type val) // 辅助函数，内部使用
	{
		assert(wcs != 0);
		while(*wcs)
		{
			if(*wcs == val)
				return true;
			else 
				++wcs;
		}
		return false;
	}
	inline size_type wcsspn(const char_type *wcs1,const char_type *wcs2)
	{
		assert(wcs1 != 0 && wcs2 != 0);
		size_type count = 0;
		while(*wcs1 && w_is_inside(wcs2,*wcs1))
			++count, ++wcs1;
		return count;
	}
	inline size_type wcscspn(const char_type *wcs1,const char_type *wcs2)
	{
		assert(wcs1 != 0 && wcs2 != 0);
		size_type count = 0;
		while(*wcs1 && !w_is_inside(wcs2,*wcs1))
			++count, ++wcs1;
		return count;
	}
	inline const char_type* wcsstr(const char_type *wcs1,const char_type *wcs2)
	{
		assert(wcs1 != 0 && wcs2 != 0);
		size_type len_1 = mystd::wcslen(wcs1);
		size_type len_2 = mystd::wcslen(wcs2);
		if(len_1 < len_2) 
			return 0;
		const char_type *search_last = wcs1 + (len_1 - len_2);
		while(wcs1 <= search_last)
		{
			if(mystd::wcsncmp(wcs1,wcs2,len_2) == 0)
				return wcs1;
			else
				++wcs1;
		}
		return 0;
	}
    inline char_type* wcsstr(char_type *wcs1,const char_type *wcs2)
	{
		assert(wcs1 != 0 && wcs2 != 0);
		return (char_type*)mystd::wcsstr((const char_type*)wcs1,wcs2);
	}

	inline const char_type* wcschr(const char_type *wcs,char_type val)
	{
		assert(wcs != 0);
		while(*wcs && *wcs != val)
			++wcs;
		if(*wcs)
			return wcs;
		else
			return 0;
	}
	inline char_type* wcschr(char_type *wcs,char_type val)
	{
		assert(wcs != 0);
		return (char_type*)mystd::wcschr((const char_type*)wcs,val);
	}
	inline const char_type* wcsrchr(const char_type *wcs,char_type val)
	{ // val可能为null wide character 
		assert(wcs != 0);
		size_type len = mystd::wcslen(wcs);
		const char_type *ptr = wcs + len;
		if(val == 0)
			return ptr;
		--ptr;
		while(len--)
			if(*ptr == val)
				return ptr;
			else
				--ptr;
		return 0;  //无匹配的字符
	}
	inline char_type* wcsrchr(char_type *wcs,char_type val)
	{  //val可能为null wide character 
		assert(wcs != 0);
		return (char_type*)mystd::wcsrchr((const char_type*)wcs,val); // 转调
	}
    
	inline const char_type* wcspbrk(const char_type *wcs1,const char_type *wcs2)
	{
		assert(wcs1 != 0 && wcs2 != 0);
		while(*wcs1 && !w_is_inside(wcs2,*wcs1))
			++wcs1;
		if(*wcs1 == 0)
			return 0;
		else
			return wcs1;
	}
	inline char_type* wcspbrk(char_type *wcs1,const char_type *wcs2)
	{
		assert(wcs1 != 0 && wcs2 != 0);
		return (char_type*)mystd::wcspbrk((const char_type*)wcs1,wcs2);
	}


MYSTD_END // end of namespace mystd 
#endif // __cplusplus
#endif // MYSTD_CWCHAR_H

下面是一个简单的测试程序

#include<iostream>
#include"cwchar.h"
#include<cwchar>
#define STD mystd // 改为std调用标准库版本
using std::endl;
using std::cout;

int main()
{
	wchar_t buf[100];
	STD::wmemcpy(buf,L"hello world",sizeof(buf) / sizeof(wchar_t));
	unsigned count = STD::wcslen(buf);
	for(unsigned i = 0; i < count; ++i)
		cout<<(char)buf[i];
	cout<<endl;



	system("pause");
	return 0;
}