代码地址

https://github.com/gongluck/Code-snippet/tree/master/cpp/code%20conversion

需求

编码转换在实际开发中经常遇到，通常是ANSI、Unicode和Utf-8之间相互转换。实现也有很多种，有查表法、使用C++11、使用boost、使用系统API。C++11和boost几乎可以实现一套代码，在linux和windows都能使用，但实际会有很多坑，相当于代码几乎不改，但是要改一下系统环境。所以有一种实现就是判断系统的版本，然后选择不同的系统api进行编码转换。

实现

目前只实现Windows下的编码转换，以后需要在linux下使用编码转换再做补充。windows下的编码转换基本围绕unicode做处理。例如ANSI->UTF-8，就是先将ANSI->unicode，再将unicode->UTF-8。

// convert.h/* * @Author: gongluck * @Date: 2020-03-23 16:06:23 * @Last Modified by: gongluck * @Last Modified time: 2020-03-23 16:09:30 */// Character encoding conversion#pragma once#include <string>namespace gconvert{// ANSI->Unicodeint ansi2uni(const std::string& ansi, std::wstring& uni);// Unicode->ANSIint uni2ansi(const std::wstring& uni, std::string& ansi);// UTF8->Unicodeint utf82uni(const std::string& utf8, std::wstring& uni);// Unicode->UTF8int uni2utf8(const std::wstring& uni, std::string& utf8);// ANSI->UTF8int ansi2utf8(const std::string& ansi, std::string& utf8);// UTF8->ANSIint utf82ansi(const std::string& utf8, std::string& ansi);} // namespace gconvert//convert.cpp/* * @Author: gongluck * @Date: 2020-03-23 16:13:01 * @Last Modified by: gongluck * @Last Modified time: 2020-03-23 16:34:50 */#include "convert.h"#include <iostream>#ifdef _WIN32#include <windows.h>#endifnamespace gconvert{#ifdef _WIN32 static int multi2uni(const std::string& multi, std::wstring& uni, UINT code) { auto len = MultiByteToWideChar(code, 0, multi.c_str(), -1, nullptr, 0); if (len <= 0) { std::cerr << __FILE__ << " : " << __LINE__ << " : " << GetLastError() << std::endl; return -1; } WCHAR* buf = new WCHAR[len]; if (buf == nullptr) { std::cerr << __FILE__ << " : " << __LINE__ << " : " << "can not new buf, size : " << len << std::endl; return -2; } len = MultiByteToWideChar(code, 0, multi.c_str(), -1, buf, len); uni.assign(buf); delete[]buf; buf = nullptr; return len; } static int uni2multi(const std::wstring& uni, std::string& multi, UINT code) { auto len = WideCharToMultiByte(code, 0, uni.c_str(), -1, nullptr, 0, nullptr, nullptr); if (len <= 0) { std::cerr << __FILE__ << " : " << __LINE__ << " : " << GetLastError() << std::endl; return -1; } CHAR* buf = new CHAR[len]; if (buf == nullptr) { std::cerr << __FILE__ << " : " << __LINE__ << " : " << "can not new buf, size : " << len << std::endl; return -2; } len = WideCharToMultiByte(code, 0, uni.c_str(), -1, buf, len, nullptr, nullptr); multi.assign(buf); delete[]buf; buf = nullptr; return len; }#endif// ANSI->Unicodeint ansi2uni(const std::string& ansi, std::wstring& uni){#ifdef _WIN32 return multi2uni(ansi, uni, CP_ACP);#endif return 0;}// Unicode->ANSIint uni2ansi(const std::wstring &uni, std::string &ansi){#ifdef _WIN32 return uni2multi(uni, ansi, CP_ACP);#endif return 0;}// UTF8->Unicodeint utf82uni(const std::string& utf8, std::wstring& uni){#ifdef _WIN32 return multi2uni(utf8, uni, CP_UTF8);#endif return 0;}// Unicode->UTF8int uni2utf8(const std::wstring& uni, std::string& utf8){#ifdef _WIN32 return uni2multi(uni, utf8, CP_UTF8);#endif return 0;}// ANSI->UTF8int ansi2utf8(const std::string &ansi, std::string &utf8){ std::wstring uni; auto len = ansi2uni(ansi, uni); if (len <= 0) { return -3; } return uni2utf8(uni, utf8);}// UTF8->ANSIint utf82ansi(const std::string &utf8, std::string &ansi){ std::wstring uni; auto len = utf82uni(utf8, uni); if (len <= 0) { return -3; } return uni2ansi(uni, ansi);}} // namespace gconvert//testcode#include <iostream>#include "../code conversion/convert.h"int main(){ std::string ansi = "你好，世界！"; std::wstring uni; std::string utf8; ret = gconvert::ansi2uni(ansi, uni); ret = gconvert::ansi2utf8(ansi, utf8); ret = gconvert::uni2ansi(uni, ansi); ret = gconvert::uni2utf8(uni, utf8); ret = gconvert::utf82ansi(utf8, ansi); ret = gconvert::utf82uni(utf8, uni); return 0;}

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