(function () {
    var C = typeof window === 'undefined' ? require('./Crypto').Crypto : window.Crypto;

    // Shortcuts
    var util = C.util;
    var charenc = C.charenc;
    var UTF8 = charenc.UTF8;
    var Binary = charenc.Binary; // Constants
    var K = [
        1116352408, 1899447441, 3049323471, 3921009573, 961987163, 1508970993, 2453635748, 2870763221, 3624381080, 310598401, 607225278, 1426881987, 1925078388, 2162078206,
        2614888103, 3248222580, 3835390401, 4022224774, 264347078, 604807628, 770255983, 1249150122, 1555081692, 1996064986, 2554220882, 2821834349, 2952996808, 3210313671,
        3336571891, 3584528711, 113926993, 338241895, 666307205, 773529912, 1294757372, 1396182291, 1695183700, 1986661051, 2177026350, 2456956037, 2730485921, 2820302411,
        3259730800, 3345764771, 3516065817, 3600352804, 4094571909, 275423344, 430227734, 506948616, 659060556, 883997877, 958139571, 1322822218, 1537002063, 1747873779,
        1955562222, 2024104815, 2227730452, 2361852424, 2428436474, 2756734187, 3204031479, 3329325298
    ];

    // Public API
    var SHA256 = (C.SHA256 = function (message, options) {
        var digestbytes = util.wordsToBytes(SHA256._sha256(message));
        return options && options.asBytes ? digestbytes : options && options.asString ? Binary.bytesToString(digestbytes) : util.bytesToHex(digestbytes);
    });

    // The core
    SHA256._sha256 = function (message) {
        // Convert to byte array
        if (message.constructor == String) {
            message = UTF8.stringToBytes(message);
        }
        /* else, assume byte array already */
        var m = util.bytesToWords(message);
        var l = message.length * 8;
        var H = [1779033703, 3144134277, 1013904242, 2773480762, 1359893119, 2600822924, 528734635, 1541459225];
        var w = [];
        var a;
        var b;
        var c;
        var d;
        var e;
        var f;
        var g;
        var h;
        var i;
        var j;
        var t1;
        var t2; // Padding
        m[l >> 5] |= 128 << (24 - (l % 32));
        m[(((l + 64) >> 9) << 4) + 15] = l;
        for (var i = 0; i < m.length; i += 16) {
            a = H[0];
            b = H[1];
            c = H[2];
            d = H[3];
            e = H[4];
            f = H[5];
            g = H[6];
            h = H[7];
            for (var j = 0; j < 64; j++) {
                if (j < 16) {
                    w[j] = m[j + i];
                } else {
                    var gamma0x = w[j - 15];
                    var gamma1x = w[j - 2];
                    var gamma0 = ((gamma0x << 25) | (gamma0x >>> 7)) ^ ((gamma0x << 14) | (gamma0x >>> 18)) ^ (gamma0x >>> 3);
                    var gamma1 = ((gamma1x << 15) | (gamma1x >>> 17)) ^ ((gamma1x << 13) | (gamma1x >>> 19)) ^ (gamma1x >>> 10);
                    w[j] = gamma0 + (w[j - 7] >>> 0) + gamma1 + (w[j - 16] >>> 0);
                }
                var ch = (e & f) ^ (~e & g);
                var maj = (a & b) ^ (a & c) ^ (b & c);
                var sigma0 = ((a << 30) | (a >>> 2)) ^ ((a << 19) | (a >>> 13)) ^ ((a << 10) | (a >>> 22));
                var sigma1 = ((e << 26) | (e >>> 6)) ^ ((e << 21) | (e >>> 11)) ^ ((e << 7) | (e >>> 25));
                t1 = (h >>> 0) + sigma1 + ch + K[j] + (w[j] >>> 0);
                t2 = sigma0 + maj;
                h = g;
                g = f;
                f = e;
                e = (d + t1) >>> 0;
                d = c;
                c = b;
                b = a;
                a = (t1 + t2) >>> 0;
            }
            H[0] += a;
            H[1] += b;
            H[2] += c;
            H[3] += d;
            H[4] += e;
            H[5] += f;
            H[6] += g;
            H[7] += h;
        }
        return H;
    };

    // Package private blocksize
    SHA256._blocksize = 16;
    SHA256._digestsize = 32;
})();