function sha256_transform()

in AliRTC2.5/Web/RtcSample/sha256.js [78:121]

• 37 lines of code
• 4 McCabe index (conditional complexity)

function sha256_transform() {
	var a, b, c, d, e, f, g, h, T1, T2;
	var W = new Array(16);

	/* Initialize registers with the previous intermediate value */
	a = ihash[0];
	b = ihash[1];
	c = ihash[2];
	d = ihash[3];
	e = ihash[4];
	f = ihash[5];
	g = ihash[6];
	h = ihash[7];

        /* make 32-bit words */
	for(var i=0; i<16; i++)
		W[i] = ((buffer[(i<<2)+3]) | (buffer[(i<<2)+2] << 8) | (buffer[(i<<2)+1] 
<< 16) | (buffer[i<<2] << 24));

        for(var j=0; j<64; j++) {
		T1 = h + sha256_Sigma1(e) + choice(e, f, g) + K256[j];
		if(j < 16) T1 += W[j];
		else T1 += sha256_expand(W, j);
		T2 = sha256_Sigma0(a) + majority(a, b, c);
		h = g;
		g = f;
		f = e;
		e = safe_add(d, T1);
		d = c;
		c = b;
		b = a;
		a = safe_add(T1, T2);
        }

	/* Compute the current intermediate hash value */
	ihash[0] += a;
	ihash[1] += b;
	ihash[2] += c;
	ihash[3] += d;
	ihash[4] += e;
	ihash[5] += f;
	ihash[6] += g;
	ihash[7] += h;
}