'분류없음'에 해당되는 글 8건

std::move가 단지 캐스팅일 뿐이라니?

일단, move 구현을 보자

template<typename _Tp>
  inline typename std::remove_reference<_Tp>::type&&
  move(_Tp&& __t)
  { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); }

move가 무엇을 하는지 자세히 보니,

static_cast<typename std::remove_reference<_Tp>::type&&>(__t);

진짜 캐스팅뿐이다. 그렇다. source object가 없어지거나 그런거 아니다.

뭐 값을 대입시킬 객체에는 rvalue reference를 넘겨서 메모리주소를 그대로 전달한다고 치고,

이시점에서 궁금한건 오로지하나,

"뭐지? 그럼 기존 객체는 어떻게 없어지는거야?"

알고보니, 그 답은 rvalue reference 생성자와 대입연산자에 있었다.

rvalue reference 생성자와 대입연산자에서는 source object의 메모리 주소를 dest object에 주고

source object는 nullptr처리하거나 하는것이다.

대표적인 예가 std::string 이다.

 assign(basic_string&& __str)
 {
    this->swap(__str);
    return *this;
 }

보면, source와 dest를 swap하고 있다. 따라서 string을 move시켜보면 move당한 놈은 "" 빈스트링을 갖게된다.

그럼 한번 테스트해볼까? 내가 만든 클레스를 move시킨면 어떻게되는지?

repl.it: https://repl.it/FbVT/0

code:

result:

아마도 이 결과로부터 유추할수있는건, 

std string처럼 swap같은건 없고 메모리는 일단 복사가되었는데 source object에 대한 후처리는 없다는 것이다. 

따라서 default move constructor가 어떻게 작동하는지 이해하고, 맘에 안든다면 직접 구현해야한다.

References

1) std::string source

2) std::remove_reference

3) What are rvalues, lvalues, xvalues, glvalues, and prvalues?

when you are comparing string from DB and Excel or CSV or .. file,

then, Just try to change file encode type to UTF-8.

or

try to match encoding type between two strings.

http://www.differencebetween.net/technology/difference-between-jit-and-interpreter/

JIT방식은 그 코드 block이 사용(호출)될때 machine code로 변환해서 사용하고 이미 한번 machine code로 변환한것은 캐싱해두었다가 변환하는 과정없이 실행한다.

Script언어의 Interpreter방식은 미리 컴파일된 함수들을 가지고 있고, code를 line by line으로 해석해서 이 함수들에게 던져준다. 

git reset --hard HEAD^

git push -f origin develop

see: https://stackoverflow.com/questions/21177078/javascript-download-csv-as-file/23786965#23786965

key point is \uFEFF

version 1.

var encodedUri = 'data:text/csv;charset=UTF-8,\uFEFF'+encodeURI(comma_data);

var link = document.createElement("a");

link.setAttribute("href", encodedUri);

var name = 'gem_use.csv';

if (key == 'container_get') {

    name = 'gem_get.csv';

}

link.setAttribute("download", name);

link.click();

version 2. (<table></table> to excel file)

usage: tablesToOneExcelSheet(tables, sheets, today+filename, 'Excel');(tables => table element id list, sheet => name list of each table)

* Should use Blob to enable large file size.

var tablesToOneExcelSheet = (function() {
        var uri = 'data:application/vnd.ms-excel;base64,'
            , tmplWorkbookXML = '<'+'?xml version="1.0"?><'+'?mso-application progid="Excel.Sheet"?><Workbook xmlns="urn:schemas-microsoft-com:office:spreadsheet" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet">'
                + '<DocumentProperties xmlns="urn:schemas-microsoft-com:office:office"><Author>NM</Author><Created>{created}</Created></DocumentProperties>'
                + '<Styles>'
                + '<Style ss:ID="Currency"><NumberFormat ss:Format="Currency"></NumberFormat></Style>'
                + '<Style ss:ID="Date"><NumberFormat ss:Format="Medium Date"></NumberFormat></Style>'
                + '</Styles>'
                + '{worksheets}</Workbook>'
            , tmplWorksheetXML = '<Worksheet ss:Name="{nameWS}"><Table>{rows}</Table></Worksheet>'
            , tmplCellXML = '<Cell{attributeStyleID}{attributeFormula}><Data ss:Type="{nameType}">{data}</Data></Cell>'
            , base64 = function(s) { return window.btoa(unescape(encodeURIComponent(s))) }
            , format = function(s, c) { return s.replace(/{(\w+)}/g, function(m, p) { return c[p]; }) }
        return function(tables, wsnames, wbname, appname) {
            var ctx = "";
            var workbookXML = "";
            var worksheetsXML = "";
            var rowsXML = "";

            for (var i = 0; i < tables.length; i++) {
                if (!tables[i].nodeType) tables[i] = document.getElementById(tables[i]);
                for (var j = 0; j < tables[i].rows.length; j++) {
                    if(i>0 && j==0) {
                        continue;
                    }
                    rowsXML += '<Row>';
                    for (var k = 0; k < tables[i].rows[j].cells.length; k++) {
                        var dataType = tables[i].rows[j].cells[k].getAttribute("data-type");
                        var dataStyle = tables[i].rows[j].cells[k].getAttribute("data-style");
                        var dataValue = tables[i].rows[j].cells[k].getAttribute("data-value");
                        dataValue = (dataValue)?dataValue:tables[i].rows[j].cells[k].innerHTML;
                        var dataFormula = tables[i].rows[j].cells[k].getAttribute("data-formula");
                        dataFormula = (dataFormula)?dataFormula:(appname=='Calc' && dataType=='DateTime')?dataValue:null;
                        ctx = {  attributeStyleID: (dataStyle=='Currency' || dataStyle=='Date')?' ss:StyleID="'+dataStyle+'"':''
                            , nameType: (dataType=='Number' || dataType=='DateTime' || dataType=='Boolean' || dataType=='Error')?dataType:'String'
                            , data: (dataFormula)?'':dataValue
                            , attributeFormula: (dataFormula)?' ss:Formula="'+dataFormula+'"':''
                        };
                        rowsXML += format(tmplCellXML, ctx);
                    }
                    rowsXML += '</Row>';
                }
            }

            ctx = {rows: rowsXML, nameWS: "Data"};
            worksheetsXML += format(tmplWorksheetXML, ctx);

            ctx = {created: (new Date()).getTime(), worksheets: worksheetsXML};
            workbookXML = format(tmplWorkbookXML, ctx);
            window.URL= window.URL || window.webkitURL;
            var blob = new Blob([workbookXML], {type: 'application/vnd.ms-excel;base64'});
            var blobUrl = window.URL.createObjectURL(blob);

            var link = document.createElement("A");
//            link.href = uri + base64(workbookXML);
            link.href = blobUrl;
            link.download = wbname || 'Workbook.xls';
            link.target = '_blank';
            document.body.appendChild(link);
            link.click();
            document.body.removeChild(link);
        }
    })();

https://github.com/djacobs/PyAPNs

Problem 1. Push notification Failed right after sending invalid token

APNS uses socket to send notification object. and if it use invalid token, that connection will be disconnected. you can overcome this by re-generating APNs Object.

But there is one more problem. If you use for loop with same APNs Object, and there is an invalid token, the tokens right after sending invalid token will be failed. 

So, there is an option named enhanced=True, it will check each tokens if it succeeded. and It uses non-blocking ssl socket, and check error using another thread. So I think there is no critical waiting. In the function "_resend_notification_by_range" It sends only notifications after invalid token.

They also provide "send_notification_multiple" function. This function doesn't check error and discard all tokens after invalid token.

Issue 1. FeedbackConnection

https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/CommunicatingWIthAPS.html#//apple_ref/doc/uid/TP40008194-CH101-SW3

- connection method and how many tokens you can receive?: 

they use socket. and It reads data using streaming until there is no data. see below