在編程的時候各種各樣的編碼轉換讓人撓頭。有的地方需要寬字符有的地方需要窄字符,需要轉換。有的地方需要UTF-8編碼,有的地方需要UTF-16編碼,需要轉換。各種各樣的編碼轉換讓人頭疼,這里呢,就梳理一下各種各種的編碼轉換方法。讓你不再為這個問題頭疼。需要注意的是有些方法引用了windows的API無法實現跨平臺。

獲取文件的編碼類型

//獲取文件的編碼 //找不到文件頭的信息的時候可能是ASCII,也可能是UTF8不帶bom頭的編碼需要自己指定一下 enum CODETYPE { ASCII, UTF8, UTF8BOM, UTF16LE, UTF16BE, UTF32LE, UTF32BE, UNKNOWN_TYPE }; CODETYPE GetFileCodeType(const char* file_path) {FILE* file = fopen(file_path, "rb");if (!file){return UNKNOWN_TYPE;}int cur_pos = ftell(file);fseek(file, 0L, SEEK_END);int file_size = ftell(file);fseek(file, cur_pos, SEEK_SET);char* buffer = (char*)malloc(file_size);fread(buffer, 1, file_size, file);fclose(file);if (file_size >= 4){if (memcmp(buffer, "\xFF\xFE\x00\x00", 4) == 0)return UTF32LE;if (memcmp(buffer, "\x00\x00\xfe\xff", 4) == 0)return UTF32BE;}if (file_size >= 3){if (memcmp(buffer, "\xEF\xBB\xBF", 3) == 0) return UTF8BOM;}if (file_size >= 2){if (memcmp(buffer, "\xFF\xFE", 2) == 0) return UTF16LE;if (memcmp(buffer, "\xFE\xFF", 2) == 0) return UTF16BE;}return UTF8; }

wchar_t轉char

char* wchar_to_char(const wchar_t* wchar) {char * m_char;int len = WideCharToMultiByte(CP_ACP, 0, wchar, (int)wcslen(wchar), NULL, 0, NULL, NULL);m_char = new char[len + 1];WideCharToMultiByte(CP_ACP, 0, wchar, (int)wcslen(wchar), m_char, len, NULL, NULL);m_char[len] = '\0';return m_char; } //結果是分配的內存記得free掉

char轉wchar_t

wchar_t* char_to_wchar(char *s){ int w_nlen=MultiByteToWideChar(CP_ACP,0,s,-1,NULL,0); wchar_t *ret; ret=(wchar_t*) malloc(sizeof(WCHAR)*w_nlen); memset(ret,0,sizeof(ret)); MultiByteToWideChar(CP_ACP,0,s,-1,ret,w_nlen); return ret; } //結果是分配的內存記得free掉

wstring轉string

std::string wstr_to_str(const std::wstring &wc) {int lenMB = ::WideCharToMultiByte(CP_ACP, 0, wc.c_str(), static_cast<int>(wc.length()), NULL, 0, NULL, NULL);std::unique_ptr<char> mb(new char[lenMB]());::WideCharToMultiByte(CP_ACP, 0, wc.c_str(), static_cast<int>(wc.length()), mb.get(), lenMB, NULL, NULL);return std::string(mb.get(), lenMB); }

string轉wstring

std::wstring str_to_wstr(const std::string &mb) {int lenWC = ::MultiByteToWideChar(CP_ACP, 0, mb.c_str(), static_cast<int>(mb.length()), NULL, 0);std::unique_ptr<wchar_t> wc(new wchar_t[lenWC]());::MultiByteToWideChar(CP_ACP, 0, mb.c_str(), static_cast<int>(mb.length()), wc.get(), lenWC);return std::wstring(wc.get(), lenWC); }

utf-8 wstring轉utf-8 string

std::string wstr_to_utf8str(const std::wstring& wc) {int lenUTF8 = WideCharToMultiByte(CP_UTF8, 0, wc.c_str(), static_cast<int>(wc.length()), NULL, 0, NULL, NULL);std::unique_ptr<char> utf8(new char[lenUTF8]());WideCharToMultiByte(CP_UTF8, 0, wc.c_str(), static_cast<int>(wc.length()), utf8.get(), lenUTF8, NULL, NULL);return std::string(utf8.get(), lenUTF8); }

utf-8 string轉utf-8 wstring

std::wstring utf8str_to_wstr(const std::string &utf8) {int lenWC = ::MultiByteToWideChar(CP_UTF8, 0, utf8.c_str(), static_cast<int>(utf8.length()), NULL, 0);std::unique_ptr<wchar_t> wc(new wchar_t[lenWC]());::MultiByteToWideChar(CP_UTF8, 0, utf8.c_str(), static_cast<int>(utf8.length()), wc.get(), lenWC);return std::wstring(wc.get(), lenWC); }

UTF-8編碼轉多字節編碼

std::string utf8_to_multibytes(const std::string& utf8) {int lenWC = ::MultiByteToWideChar(CP_UTF8, 0, utf8.c_str(), static_cast<int>(utf8.length()), NULL, 0);std::unique_ptr<wchar_t> wc(new wchar_t[lenWC]());::MultiByteToWideChar(CP_UTF8, 0, utf8.c_str(), static_cast<int>(utf8.length()), wc.get(), lenWC);int lenMB = ::WideCharToMultiByte(CP_ACP, 0, wc.get(), lenWC, NULL, 0, NULL, NULL);std::unique_ptr<char> mb(new char[lenMB]());::WideCharToMultiByte(CP_ACP, 0, wc.get(), lenWC, mb.get(), lenMB, NULL, NULL);return std::string(mb.get(), lenMB); }

多字節編碼轉UTF-8編碼

std::string multibytes_to_utf8(const std::string &mb) {int lenWC = ::MultiByteToWideChar(CP_ACP, 0, mb.c_str(), static_cast<int>(mb.length()), NULL, 0);std::unique_ptr<wchar_t> wc(new wchar_t[lenWC]());::MultiByteToWideChar(CP_ACP, 0, mb.c_str(), static_cast<int>(mb.length()), wc.get(), lenWC);int lenUTF8 = ::WideCharToMultiByte(CP_UTF8, 0, wc.get(), lenWC, NULL, 0, NULL, NULL);std::unique_ptr<char> utf8(new char[lenUTF8]());::WideCharToMultiByte(CP_UTF8, 0, wc.get(), lenWC, utf8.get(), lenUTF8, NULL, NULL);return std::string(utf8.get(), lenUTF8); }

大端對齊轉小端對齊

void big_to_little(wchar_t* src, unsigned int size) {for (usigned int iix = 0; iix < size; ++iix, ++src) {*src = (((*src) & 0xff00) >> 8) | (((*src) & 0x00ff) << 8);} }

總結

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