How to write a sequence of bytes to binary file using JScript? - binary

Question

I'm trying to write Array(1, 2) to binary file as bytes.
So output file should contain 00000001 00000010.
I understood that I have to use ADODB.Stream, but I haven't found any solution for such simple task.
var data = new Array(1, 2)
out = WScript.CreateObject("ADODB.Stream")
out.Type = 1
out.Open()
out.Write(data)
out.SaveToFile("output.bin", 2)
out.Close()
Code above gives error:
Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another.
Any ideas how to convert data array to acceptable type?

Answer 1

You can use the WriteAll function described here: Reading and Writing Binary Files Using JScript. Copyright: Dr Alexander J Turner.
Please note, the Stream shall be of type text, and then you will need to do the text<->binary conversion.
I just tested all the code and it worked fine for me.
Here is a complete example:
var bf1 = new BinaryFile("C:/Temp/test.bin");
var outBuf = '';
for(var i=0, l=data.length; i<l; i++) {
outBuf += String.fromCharCode(data[i]);
}
bf1.WriteAll(outBuf);
The result looks like this:
EDIT:
I just did a more compact adaptation of the code, to avoid the hex conversion and the double loop:
// Codepage conversion table
var _c=[199,252,233,226,228,224,229,231,234,235,232,239,238,236,196,197,
201,230,198,244,246,242,251,249,255,214,220,162,163,165,8359,402,
225,237,243,250,241,209,170,186,191,8976,172,189,188,161,171,187,
9617,9618,9619,9474,9508,9569,9570,9558,9557,9571,9553,9559,9565,9564,9563,9488,
9492,9524,9516,9500,9472,9532,9566,9567,9562,9556,9577,9574,9568,9552,9580,9575,
9576,9572,9573,9561,9560,9554,9555,9579,9578,9496,9484,9608,9604,9612,9616,9600,
945,223,915,960,931,963,181,964,934,920,937,948,8734,966,949,8745,
8801,177,8805,8804,8992,8993,247,8776,176,8729,183,8730,8319,178,9632,160],
_w=[],
_r=[];
// Create forward lookup to write & reverse lookup to read
for(var i=0, l=256; i<l; i++) {
var c = (i<128) ? i : _c[i-128];
_w[i] = c;
_r[c] = i;
}
// Read binary data from disk
function binFileToArray(fileName, binArray){
var inStream = new ActiveXObject("ADODB.Stream");
inStream.Type = 2;
inStream.CharSet = '437';
inStream.Open();
inStream.LoadFromFile(fileName);
var inString = inStream.ReadText();
inStream.Close();
for(var i=0, l=inString.length; i<l; i++) {
binArray.push(_r[inString.charCodeAt(i)]);
}
}
// Write binary data to disk
function binArrayToFile(binArray, fileName){
var outStream = new ActiveXObject('ADODB.Stream');
var outString = '';
for(var i=0, l=binArray.length; i<l; i++) {
outString += String.fromCharCode(_w[binArray[i]]);
}
outStream.Type = 2;
outStream.CharSet = '437';
outStream.Open();
outStream.WriteText(outString);
outStream.SaveToFile(fileName, 2);
outStream.Close();
}
// TEST: read binary file from disk & write array back to disk
var testArray = [];
binFileToArray('c:/temp/test.bin', testArray);
binArrayToFile(testArray, 'c:/temp/test2.bin');
// both files equals