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 __cplusplusMYSTD_BEGINtypedef 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;elsereturn *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;elsereturn *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;elsereturn 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;elsereturn 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;}