c++ 编码转换（C语言编码转换）

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。

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 // 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->Unicode int ansi2uni(const std::string& ansi, std::wstring& uni); // Unicode->ANSI int uni2ansi(const std::wstring& uni, std::string& ansi); // UTF8->Unicode int utf82uni(const std::string& utf8, std::wstring& uni); // Unicode->UTF8 int uni2utf8(const std::wstring& uni, std::string& utf8); // ANSI->UTF8 int ansi2utf8(const std::string& ansi, std::string& utf8); // UTF8->ANSI int utf82ansi(const std::string& utf8, std::string& ansi); } // namespace gconvert

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 //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> #endif namespace 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->Unicode int ansi2uni(const std::string& ansi, std::wstring& uni) { #ifdef _WIN32 return multi2uni(ansi, uni, CP_ACP); #endif return 0; } // Unicode->ANSI int uni2ansi(const std::wstring &uni, std::string &ansi) { #ifdef _WIN32 return uni2multi(uni, ansi, CP_ACP); #endif return 0; } // UTF8->Unicode int utf82uni(const std::string& utf8, std::wstring& uni) { #ifdef _WIN32 return multi2uni(utf8, uni, CP_UTF8); #endif return 0; } // Unicode->UTF8 int uni2utf8(const std::wstring& uni, std::string& utf8) { #ifdef _WIN32 return uni2multi(uni, utf8, CP_UTF8); #endif return 0; } // ANSI->UTF8 int 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->ANSI int 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

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 //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; }