常用字符串编码转换的函数

#include <windows.h>#include <string>/// @brief ascii和unicode之间的编码转换 size_t ascii_to_unicode(const char* src, wchar_t* dest, size_t dest_len, size_t src_len = 0){    if(src_len == 0)        src_len = strlen(src);    return MultiByteToWideChar(CP_ACP, 0, src, static_cast<int>(src_len),         dest, static_cast<int>(dest_len));}size_t unicode_to_ascii(const wchar_t* src, char* dest, size_t dest_len, size_t src_len = 0){    if(src_len == 0)        src_len = wcslen(src);    return WideCharToMultiByte(CP_ACP, 0, src, static_cast<int>(src_len),         dest, static_cast<int>(dest_len), NULL, NULL);}/// @brief utf8和unicode之间的编码转换 size_t utf8_to_unicode(const unsigned char* src, wchar_t* dest, size_t dest_len, size_t src_len = 0){    if(src_len == 0)        src_len = strlen((const char*)src);    return MultiByteToWideChar(CP_UTF8, 0, (const char*)src, static_cast<int>(src_len),         dest, static_cast<int>(dest_len));}size_t unicode_to_utf8(const wchar_t* src, unsigned char* dest, size_t dest_len, size_t src_len = 0){    if(src_len == 0)        src_len = wcslen(src);    return WideCharToMultiByte(CP_UTF8, 0, src, static_cast<int>(src_len),         (char*)dest, static_cast<int>(dest_len), NULL, NULL);}/// @brief ascii和utf8之间的编码转换 size_t ascii_to_utf8(const char* src, unsigned char* dest, size_t dest_len, size_t src_len = 0){    if(src_len == 0)        src_len = strlen(src);    std::wstring unicode(src_len, 0);    unicode.resize(        ascii_to_unicode(src, const_cast<wchar_t*>(unicode.data()), unicode.size(), src_len));    return unicode_to_utf8(unicode.data(), dest, dest_len, unicode.size());}size_t utf8_to_ascii(const unsigned char* src, char* dest, size_t dest_len, size_t src_len = 0){    if(src_len == 0)        src_len = strlen((const char*)src);    std::wstring unicode(src_len * 2, 0);    unicode.resize(        utf8_to_unicode(src, const_cast<wchar_t*>(unicode.data()), unicode.size(), src_len));    return unicode_to_ascii(unicode.data(), dest, dest_len, unicode.size());}/// @brief 普通字符串转宽字符串 std::wstring& to_wstring(const char* str, size_t len, std::wstring& ret){    if(len == 0)        len = strlen(str);    ret.resize(len);    ret.resize(ascii_to_unicode(str, const_cast<wchar_t*>(ret.data()), ret.size(), len));    return ret;}std::wstring to_wstring(const char* str, size_t len = 0){    std::wstring ret;    return to_wstring(str, len, ret);}std::wstring to_wstring(const std::string& str){    std::wstring ret;    return to_wstring(str.data(), str.size(), ret);}std::wstring& to_wstring(const std::string& str, std::wstring& ret){    return to_wstring(str.data(), str.size(), ret);}/// @brief 宽字符串转普通字符串 std::string& to_string(const wchar_t* str, size_t len, std::string& ret){    if(len == 0)        len = wcslen(str);    ret.resize(len * 2);    ret.resize(unicode_to_ascii(str, const_cast<char*>(ret.data()), ret.size(), len));    return ret;}std::string to_string(const wchar_t* str, size_t len){    std::string ret;    return to_string(str, len, ret);}std::string to_string(const std::wstring& str){    std::string ret;    return to_string(str.data(), str.size(), ret);}std::string& to_string(const std::wstring& str, std::string& ret){    return to_string(str.data(), str.size(), ret);}

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