bytes.js: Just some functions to help out with byteArrays.

bytes.js

/*
Just some functions to help out with byteArrays.

Authors and Inspiration: github.com/adoc and Various Others.
*/

// Converts an integer to bytes.
var intToBytes = function(n) {
    var result = '';
    while (n) {
        result = String.fromCharCode(n & 0xFF) + result;
        n >>= 8;
    }
    return result;
}

// Converts bytes to an integer.
var bytesToInt = function(b) {
    var n = 0;
    var blen = b.length;
    for(i=0; i<blen; i++) {
        n += b[blen-i-1].charCodeAt() << 8 * i;
    }
    return n;
}

// http://stackoverflow.com/a/11893415
function wordsToBytes(wordArray) {
    var byteArray = [], word, i, j;
    for (i = 0; i < wordArray.length; ++i) {
        word = wordArray[i];
        for (j=3; j >= 0; --j) {
            byteArray.push((word >> 8 * j) & 0xFF);
        }
    }
    return byteArray;
}

// Array of bytes to a WordArray.
function bytesToWords(byteArray) {
    var wordArray = [];
    for (var i=0; i<Math.ceil(byteArray.length/4); i++) {
        wordArray[i] = 0;
    }
    for (var i=0; i<byteArray.length; i++) {
        var wi = (i - (i % 4)) / 4;
        var j = 3 - i % 4;
        wordArray[wi] += byteArray[i] << 8 * j;
    }
    return wordArray;
}

// byteArray to String. Also appends to `outString`.
function bytesToString(byteArray, outString) {
    outString = outString || '';
    for (var i=0; i<byteArray.length; i++) {
        outString += String.fromCharCode(byteArray[i]);
    }
    return outString;
}

// String to byteArray. Also appends to `byteArray`.
function stringToBytes(string, byteArray) {
    byteArray = byteArray || [];
    for (var i=0; i<string.length; i++) {
        byteArray.push(string[i].charCodeAt());
    }
    return byteArray;
}

// Strips trailing 0 bytes.
function stripArray(byteArray) {
    for (var i=byteArray.length; i>0; i--) {
        if (byteArray[i-1] == 0) {
            byteArray.splice(i-1, 1);
        } else {
            return byteArray;
        }
    }
}