javascript003

function md5(str, rawOutput){
    // Algorithmus aus http://de.wikipedia.org/wiki/Message-Digest_Algorithm_5
    var btes;
    if (typeof str === "string" || str instanceof String){
        // Byteweises einlesen des Eingabestrings
        btes = [];
        for (var i = 0; i < str.length; i++){
            var chr = str.charCodeAt(i);
            while (chr > 255){
                var helpChr = chr;
                var rot = 0;
                while (helpChr > 255){
                    helpChr >>= 8;
                    rot++;
                }
                btes.push(helpChr);
                chr = chr & ((1<<(rot*8)) - 1);
            }
            btes.push(chr);
        }
    }
    else {
        btes = Array.prototype.slice.call(str);
    }

    var r = [
         7, 12, 17, 22,  7, 12, 17, 22,  7, 12,
        17, 22,  7, 12, 17, 22,  5,  9, 14, 20,
         5,  9, 14, 20,  5,  9, 14, 20,  5,  9,
        14, 20,  4, 11, 16, 23,  4, 11, 16, 23,
         4, 11, 16, 23,  4, 11, 16, 23,  6, 10,
        15, 21,  6, 10, 15, 21,  6, 10, 15, 21,
         6, 10, 15, 21
    ];
    /*
    var bitLength = 0xFFFFFFFF + 1;
    var k = new Array(64);
    for (var i = 0; i < 64; i++){
        k[i] = int32(Math.floor(Math.abs(Math.sin(i + 1) * bitLength)));
    }
    /* Nachfolgende Zeile koennte vielleicht etwas performanter sein, da nichts berechnet werden muss - das Ergebnis ist das selbe.*/
    var k = [
        0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf,
        0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af,
        0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e,
        0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
        0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6,
        0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8,
        0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122,
        0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
        0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039,
        0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244, 0x432aff97,
        0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d,
        0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
        0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
    ];

    var h0 = 0x67452301;
    var h1 = 0xEFCDAB89;
    var h2 = 0x98BADCFE;
    var h3 = 0x10325476;

    var messageBitLength = btes.length * 8;
    btes.push(0x80);
    while(btes.length % 64 !== 56){
        btes.push(0);
    }

    for (var i = 0; i < 8; i++){
        var bte = messageBitLength & 255;
        btes.push(bte);
        messageBitLength >>>= 8;
    }

    for (var i = 0; i < btes.length; i += 64){
        var w = new Array(16);
        for (var j = 0; j < 16; j++){
            w[j] = int32(
                    int32(btes[i + 3 + (j*4)] << 24) |
                    int32(btes[i + 2 + (j*4)] << 16) |
                    int32(btes[i + 1 + (j*4)] << 8 ) |
                    int32(btes[i + 0 + (j*4)] << 0 )
                );
        }

        var a = h0;
        var b = h1;
        var c = h2;
        var d = h3;

        var f, g;
        for (var j = 0; j < 64; j++){
            if (j < 16){
                //f = int32(int32(b & c) | int32(int32(~b) & d)); // Originalverarbeitung
                f = int32(d ^ int32(b & int32(c ^ d)));
                g = j;
            }
            else if (j < 32){
                //f = int32(int32(b & d) | int32(c & int32(~d))); // Originalverarbeitung
                f = int32(c ^ int32(d & int32(b ^ c)));
                g = (5*j + 1) % 16;
            }
            else if (j < 48){
                f = int32(int32(b ^ c) ^ d);
                g = (3*j + 5) % 16;
            }
            else {
                f = int32(c ^ int32(b | int32(~ d)));
                g = (7*j) % 16;
            }
            var temp = d;
            d = c;
            c = b;
            b = int32(leftRotate(a + f + k[j] + w[g], r[j]) + b);
            a = temp;
        }

        h0 = int32(h0 + a);
        h1 = int32(h1 + b);
        h2 = int32(h2 + c);
        h3 = int32(h3 + d);
    }

    if (rawOutput){
        return toLittleEndian(h0) +
            toLittleEndian(h1) +
            toLittleEndian(h2) +
            toLittleEndian(h3);
    }
    else {
        return reverse(toHex(h0, 8), 2) + reverse(toHex(h1, 8), 2) + reverse(toHex(h2, 8), 2) + reverse(toHex(h3, 8), 2);
    }
}