自学教程：C++ utf16_to_utf8函数代码示例

void CWndStyleEditor::OnBnClickedSelectPic(){	if(NULL == SQRGUIStyleManager::GetInst()->GetActiveStyle())		return;	// TODO: Add your control notification handler code here	CString FileName = GetFileName(true, L"GUI Texture (*.tex *.dds)|*.tex;*.dds||");		SQRGUIStyle* pStyle = SQRGUIStyleManager::GetInst()->GetActiveStyle();		CString CurPath = utf8_to_utf16(pStyle->GetTexturePath()).c_str();	CurPath.MakeLower();	wstring Str = FileName.GetBuffer();	wstring TexStr = Str.substr(Str.rfind(L"//") + 1, Str.size());	CString TexPath = Str.substr(0, Str.rfind(L"//") + 1).c_str();	if(m_pStyleStruct!=NULL &&		Str.size()>0 &&		m_pStyleStruct->m_TexString!=utf16_to_utf8(TexStr).c_str() &&		TexPath == CurPath )	{		m_pStyleStruct->m_TexString = utf16_to_utf8(TexStr).c_str();		m_pStyleStruct->Release();		CGraphic::GetInst()->CreateTexture(L"",  			(SQRGUIStyleManager::GetInst()->GetActiveStyle()->GetTexturePath()+utf16_to_utf8(TexStr)).c_str(),			&(m_pStyleStruct->pTexture) );		m_TextureEdit.SetWindowText(TexStr.c_str());		RefreshMaskList();	}}

void win32_windowed_app_setup_params::trace_dump() const {    TRACE("hinstance : {:x}", (unsigned int)get_hinstance());    TRACE("window_class_name : {}", utf16_to_utf8(get_window_class_name()));    TRACE("window_caption : {}", utf16_to_utf8(get_window_caption()));    TRACE("min_window_size : {}", get_min_window_size());    TRACE("small_icon_id : {}", get_small_icon_id());    TRACE("large_icon_id : {}", get_large_icon_id());    TRACE("is_visible_by_default : {}", bool_to_string(get_is_visible_by_default()));}

const char* CBaseScriptApp::GetXMLFilePath(const char* szRelaFilePath) const{	if ( !szRelaFilePath )		m_szXMLFilePath = utf16_to_utf8(m_pXMLPathMgr->GetFullPath(NULL));	else		m_szXMLFilePath = utf16_to_utf8(m_pXMLPathMgr->GetFullPath(utf8_to_utf16(szRelaFilePath).c_str()));	return m_szXMLFilePath.c_str();}

//------------------------------------------------------------------------------CPostEffectLoader::CPostEffectLoader( const string& fileName ){	// load xml file	wstring path = CGraphic::GetInst()->GetShaderConfigPath();	path.append(utf8_to_utf16(fileName));	ipkgstream stream;	if ( stream.open(PATH_ALIAS_SHD.c_str(), utf16_to_utf8(path).c_str()) != 0 )		GenErr( GraphicErr::GetErrTypeStr(ShaderInit_Err), "can't open " + utf16_to_utf8(path) );	pPostEffectCfg = new CXmlConfig( "PostProcess" , stream );	xmlConfig = pPostEffectCfg->GetRootNode();}

int utf16_to_utf8_alloc(void **d,short *s){    int len;    char *d8;    static char *funcname="utf16_to_utf8_alloc";    (*d)=NULL;    len=utf16_to_utf8(NULL,s,-1);    willus_mem_alloc_warn(d,len+1,funcname,10);    d8=(char *)(*d);    utf16_to_utf8(d8,s,len);    return(len);}

void init_commandline_arguments_utf8(int *argc, char ***argv){	int i, nArgs;	LPWSTR *szArglist;	szArglist = CommandLineToArgvW(GetCommandLineW(), &nArgs);	if(NULL == szArglist)	{		fprintf(stderr, "/nFATAL: CommandLineToArgvW failed/n/n");		exit(-1);	}	*argv = (char**) malloc(sizeof(char*) * nArgs);	*argc = nArgs;	if(NULL == *argv)	{		fprintf(stderr, "/nFATAL: Malloc failed/n/n");		exit(-1);	}		for(i = 0; i < nArgs; i++)	{		(*argv)[i] = utf16_to_utf8(szArglist[i]);		if(NULL == (*argv)[i])		{			fprintf(stderr, "/nFATAL: utf16_to_utf8 failed/n/n");			exit(-1);		}	}	LocalFree(szArglist);}

/// Gets the hostname of the current machine.////// @param hostname   Buffer to store the hostname./// @param size       Size of `hostname`.void os_get_hostname(char *hostname, size_t size){#ifdef HAVE_SYS_UTSNAME_H  struct utsname vutsname;  if (uname(&vutsname) < 0) {    *hostname = '/0';  } else {    xstrlcpy(hostname, vutsname.nodename, size);  }#elif defined(WIN32)  wchar_t host_utf16[MAX_COMPUTERNAME_LENGTH + 1];  DWORD host_wsize = sizeof(host_utf16) / sizeof(host_utf16[0]);  if (GetComputerNameW(host_utf16, &host_wsize) == 0) {    *hostname = '/0';    DWORD err = GetLastError();    EMSG2("GetComputerNameW failed: %d", err);    return;  }  host_utf16[host_wsize] = '/0';  char *host_utf8;  int conversion_result = utf16_to_utf8(host_utf16, &host_utf8);  if (conversion_result != 0) {    EMSG2("utf16_to_utf8 failed: %d", conversion_result);    return;  }  xstrlcpy(hostname, host_utf8, size);  xfree(host_utf8);#else  EMSG("os_get_hostname failed: missing uname()");  *hostname = '/0';#endif}

static void swkbdMessageCallback(void* user, NS_APPID sender, void* msg, size_t msgsize){	SwkbdExtra* extra = (SwkbdExtra*)user;	SwkbdState* swkbd = (SwkbdState*)msg;	if (sender != APPID_SOFTWARE_KEYBOARD || msgsize != sizeof(SwkbdState))		return;	u16* text16 = (u16*)(swkbdSharedMem + swkbd->text_offset);	ssize_t units = utf16_to_utf8(NULL, text16, 0);	if (units < 0) svcBreak(USERBREAK_PANIC); // Shouldn't happen.	char* text8 = (char*)malloc(units+1);	if (!text8) svcBreak(USERBREAK_PANIC); // Shouldn't happen.	swkbdConvertToUTF8(text8, text16, units);	const char* retmsg = NULL;	swkbd->callback_result = extra->callback(extra->callback_user, &retmsg, text8, units);	if (swkbd->callback_result > SWKBD_CALLBACK_OK)		swkbdConvertToUTF16(swkbd->callback_msg, retmsg, SWKBD_MAX_CALLBACK_MSG_LEN);	else		swkbd->callback_msg[0] = 0;	free(text8);	APT_SendParameter(envGetAptAppId(), sender, APTCMD_MESSAGE, swkbd, sizeof(*swkbd), 0);}

void CRenderFont::DrawText( const RenderTextParam& param ){	if (wcslen(param.GetText())==0)		return;	this->realFont->SetAlignToPixel(m_bAlignToPixel);	this->realFont->Resize(param.GetSize());	this->Begin();#ifdef CATCH_DRAWTEXT_EXCEPTION	SQR_TRY	{		this->realFont->DrawText(param);	}	SQR_CATCH(exp)	{		exp.AppendMsg(" - realFont->DrawText(param) евакрЛЁё/n");		const wstring drawText = param.GetText();		const string u8drawText = utf16_to_utf8(drawText.c_str());		exp.AppendMsg(u8drawText.c_str());		GfkLogExp(exp);	}	SQR_TRY_END#else	this->realFont->DrawText(param);#endif	this->End();}

static int read_usec(sd_id128_t vendor, const char *name, usec_t *u) {        _cleanup_free_ void *i = NULL;        _cleanup_free_ char *j = NULL;        size_t is;        int r;        uint64_t x;        assert(name);        assert(u);        r = efi_get_variable(EFI_VENDOR_LOADER, name, NULL, &i, &is);        if (r < 0)                return r;        j = utf16_to_utf8(i, is);        if (!j)                return -ENOMEM;        r = safe_atou64(j, &x);        if (r < 0)                return r;        *u = x;        return 0;}

int efi_get_loader_device_part_uuid(sd_id128_t *u) {        _cleanup_free_ void *s = NULL;        _cleanup_free_ char *p = NULL;        size_t ss;        int r, parsed[16];        unsigned i;        assert(u);        r = efi_get_variable(EFI_VENDOR_LOADER, "LoaderDevicePartUUID", NULL, &s, &ss);        if (r < 0)                return r;        p = utf16_to_utf8(s, ss);        if (!p)                return -ENOMEM;        if (sscanf(p, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",                   &parsed[0], &parsed[1], &parsed[2], &parsed[3],                   &parsed[4], &parsed[5], &parsed[6], &parsed[7],                   &parsed[8], &parsed[9], &parsed[10], &parsed[11],                   &parsed[12], &parsed[13], &parsed[14], &parsed[15]) != 16)                return -EIO;        for (i = 0; i < ELEMENTSOF(parsed); i++)                u->bytes[i] = parsed[i];        return 0;}

void CWndStyleEditor::OnBnClickedStyleOk(){	// TODO: Add your control notification handler code here	CString str;	m_StylesList.GetWindowText(str);	SQRGUIStyle* pStyle = SQRGUIStyleManager::GetInst()->ActiveStyle(utf16_to_utf8(str.GetBuffer()).c_str());	( ( ::CButton* )GetDlgItem( IDC_ABUTTON ) )		->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_ACHECKBUTTON ) )->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_ACOMBOBOX ) )	->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_AEDIT ) )		->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_ARICHTEXT ) )	->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_APROGRESS ) )	->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_ASCROLLBAR ) )	->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_ASPIN ) )		->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_ASTATIC ) )		->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_ALISTCTRL ) )	->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_ATREECTRL ) )	->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_AWNDMOVE ) )	->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_CLOCK ) )		->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_CHART ) )		->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_AICON2 ) )		->SetCheck( 0 ) ;	( ( ::CButton* )GetDlgItem( IDC_CWnd ) )		->SetCheck( 1 ) ;	OnBnClickedCWnd();	RefreshMaskList();}

void CBaseScriptApp::ConfigSearchPath(){	const char DEFAULT_SEARCH_PATH_NODE[128] = "default";	// 加载搜索路径配置文件	CXmlConfig* pXmlDirectory = LoadCfgFile( "etc/common/Directory.xml", "directory" );	string setting_path = pXmlDirectory->Get<string>(DEFAULT_SEARCH_PATH_NODE, "setting_path");	string xml_path = pXmlDirectory->Get<string>(DEFAULT_SEARCH_PATH_NODE, "xml_path");	string gui_path = pXmlDirectory->Get<string>(DEFAULT_SEARCH_PATH_NODE, "gui_path");	string lang_path = pXmlDirectory->Get<string>(DEFAULT_SEARCH_PATH_NODE, "lang_path");	string res_path = pXmlDirectory->Get<string>(DEFAULT_SEARCH_PATH_NODE, "res_path");	AddLoadPath("cfg", setting_path, true);	AddLoadPath("gui", gui_path, false);	AddLoadPath("res", res_path, false);	AddLoadPath("lan", lang_path, false);	AddLoadPath("shd", utf16_to_utf8(m_pRootPathMgr->GetRootPath()).c_str(), false);	// 创建各路径管理器	m_pCfgPathMgr	= new CPathMgr( setting_path.c_str() );	m_pXMLPathMgr	= new CPathMgr( xml_path.c_str() );	m_pGUIPathMgr	= new CPathMgr( gui_path.c_str() );	m_pLangPathMgr	= new CPathMgr( lang_path.c_str() );	m_pResPathMgr	= new CPathMgr();	m_pResPathMgr->SetCurPath( utf8_to_utf16(res_path).c_str() );	SafeDelete(pXmlDirectory);	}

bool ComputeHash_FromText(const int hashType, const TCHAR *const textData, TCHAR *const hashOut, const size_t hashOutSize){	const size_t hashSize = GetHashSize(hashType);	if((hashSize == SIZE_MAX) || (hashSize >= (hashOutSize / 2)))	{		if(hashSize != SIZE_MAX) ERROR_MSG(T("Output buffer is too small to hold the hash value!"));		return false;	}	hash_ctx ctx;	if(!HashFunction_Init(hashType, &ctx))	{		return false;	}#ifdef UNICODE	const char *const textUtf8 = utf16_to_utf8(textData);	if(textUtf8 == NULL)	{		return false;	}	HashFunction_Update(&ctx, (BYTE*)textUtf8, strlen(textUtf8));	delete [] textUtf8;#else	HashFunction_Update(&ctx, (BYTE*)textData, strlen(textData));#endif	BYTE hashValue[128];	HashFunction_Final(&ctx, hashValue);	ConvertHashToHex(hashSize, hashValue, hashOut);	return true;};

static const char* _vd3deName(struct VDirEntry* vde) {	struct VDirEntry3DS* vd3de = (struct VDirEntry3DS*) vde;	if (!vd3de->utf8Name[0]) {		utf16_to_utf8((uint8_t*) vd3de->utf8Name, vd3de->ent.name, sizeof(vd3de->utf8Name));	}	return vd3de->utf8Name;}

/* Strings, CS0 (UDF 2.1.1) */static char *_cs0_to_utf8(const uint8_t *cs0, size_t size){    size_t   out_pos = 0;    size_t   out_size = size;    size_t   i;    uint8_t *out = (uint8_t *)malloc(size);    if (!out) {        udf_error("out of memory/n");        return NULL;    }    switch (cs0[0]) {    case 8:        /*udf_trace("string in utf-8/n");*/        for (i = 1; i < size; i++) {            utf16lo_to_utf8(out, out_pos, out_size, cs0[i]);        }        break;    case 16:        for (i = 1; i < size; i+=2) {            uint16_t ch = cs0[i + 1] | (cs0[i] << 8);            utf16_to_utf8(out, out_pos, out_size, ch);        }        break;    default:        udf_error("unregonized string encoding %u/n", cs0[0]);        free(out);        return NULL;    }    out[out_pos] = 0;    return (char*)out;}

void CWndStyleEditor::OnBnClickedStyleDel(){	// TODO: Add your control notification handler code here	CString str;	m_StylesList.GetWindowText(str);	SQRGUIStyleManager::GetInst()->DelStyle(utf16_to_utf8(str.GetBuffer()).c_str());	RefreshList();}

void CBaseScriptApp::ChangeCurPathToRes(){#ifdef _WIN32	_wchdir(m_pResPathMgr->GetCurPath());#else	chdir( utf16_to_utf8(m_pResPathMgr->GetCurPath()).c_str() );#endif}

static Value wstr_to_file(RefStr *base_dir, const wchar_t *wp, int size){    int fname_len = utf16_to_utf8(NULL, wp, size);    int basedir_last_sep = (base_dir->c[base_dir->size - 1] == SEP_C);    int total_len = base_dir->size + (basedir_last_sep ? 0 : 1) + fname_len;    RefStr *rs_name = fs->refstr_new_n(fs->cls_file, total_len);    char *dst = rs_name->c;    memcpy(dst, base_dir->c, base_dir->size);    dst += base_dir->size;    if (!basedir_last_sep) {        *dst++ = SEP_C;    }    utf16_to_utf8(dst, wp, size);    return vp_Value(rs_name);}

	//-----------------------------------------------------------------//	inline strings strings_to_strings(const wstrings& src) noexcept {		strings dst;		for(const auto& ws : src) {			auto tmp = utf16_to_utf8(ws);			dst.push_back(tmp);		}		return dst;	}

static int task_populate_files_compare_directory_entries(const void* e1, const void* e2) {    FS_DirectoryEntry* ent1 = (FS_DirectoryEntry*) e1;    FS_DirectoryEntry* ent2 = (FS_DirectoryEntry*) e2;    if((ent1->attributes & FS_ATTRIBUTE_DIRECTORY) && !(ent2->attributes & FS_ATTRIBUTE_DIRECTORY)) {        return -1;    } else if(!(ent1->attributes & FS_ATTRIBUTE_DIRECTORY) && (ent2->attributes & FS_ATTRIBUTE_DIRECTORY)) {        return 1;    } else {        char entryName1[0x213] = {'/0'};        utf16_to_utf8((uint8_t*) entryName1, ent1->name, sizeof(entryName1) - 1);        char entryName2[0x213] = {'/0'};        utf16_to_utf8((uint8_t*) entryName2, ent2->name, sizeof(entryName2) - 1);        return strcasecmp(entryName1, entryName2);    }}

static std::string get_string_from_utf16(const char16_t* input, int input_len) {    ssize_t utf8_length = utf16_to_utf8_length(input, input_len);    if (utf8_length <= 0) {        return {};    }    std::string utf8;    utf8.resize(utf8_length);    utf16_to_utf8(input, input_len, &*utf8.begin(), utf8_length + 1);    return utf8;}

Result udsGetNodeInfoUsername(const udsNodeInfo *nodeinfo, char *username){	ssize_t units=0;	size_t len = 10;	units = utf16_to_utf8((uint8_t*)username, (uint16_t*)nodeinfo->username, len);	if(units < 0 || units > len)return -2;	return 0;}

static GtkWidget *vcard_get_preview (EImport *ei,                   EImportTarget *target,                   EImportImporter *im){	GtkWidget *preview;	GSList *contacts;	gchar *contents;	VCardEncoding encoding;	EImportTargetURI *s = (EImportTargetURI *) target;	gchar *filename;	filename = g_filename_from_uri (s->uri_src, NULL, NULL);	if (filename == NULL) {		g_message (G_STRLOC ": Couldn't get filename from URI '%s'", s->uri_src);		return NULL;	}	encoding = guess_vcard_encoding (filename);	if (encoding == VCARD_ENCODING_NONE) {		g_free (filename);		return NULL;	}	if (!g_file_get_contents (filename, &contents, NULL, NULL)) {		g_message (G_STRLOC ": Couldn't read file.");		g_free (filename);		return NULL;	}	g_free (filename);	if (encoding == VCARD_ENCODING_UTF16) {		gchar *tmp;		gunichar2 *contents_utf16 = (gunichar2 *) contents;		tmp = utf16_to_utf8 (contents_utf16);		g_free (contents);		contents = tmp;	} else if (encoding == VCARD_ENCODING_LOCALE) {		gchar *tmp;		tmp = g_locale_to_utf8 (contents, -1, NULL, NULL, NULL);		g_free (contents);		contents = tmp;	}	contacts = eab_contact_list_from_string (contents);	g_free (contents);	preview = evolution_contact_importer_get_preview_widget (contacts);	e_client_util_free_object_slist (contacts);	return preview;}

static void test_utf16_to_utf8(void) {        char *a = NULL;        const uint16_t utf16[] = { htole16('a'), htole16(0xd800), htole16('b'), htole16(0xdc00), htole16('c'), htole16(0xd801), htole16(0xdc37) };        const char utf8[] = { 'a', 'b', 'c', 0xf0, 0x90, 0x90, 0xb7, 0 };        a = utf16_to_utf8(utf16, 14);        assert_se(a);        assert_se(streq(a, utf8));        free(a);}

std::string utf16ToUtf8(const StringPiece16& utf16) {    ssize_t utf8Length = utf16_to_utf8_length(utf16.data(), utf16.length());    if (utf8Length <= 0) {        return {};    }    std::string utf8;    utf8.resize(utf8Length);    utf16_to_utf8(utf16.data(), utf16.length(), &*utf8.begin());    return utf8;}

void CWndStyleEditor::OnBnClickedStyleAdd(){	// TODO: Add your control notification handler code here	CString str;	m_StylesList.GetWindowText(str);	SQRGUIStyleManager::GetInst()->AddStyle(utf16_to_utf8(str.GetBuffer()).c_str());	CString path = L"..//gui//style//" + str;	_wmkdir(path.GetBuffer());	RefreshList();}