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#include <string.h>
#include "sha256_mb.h"

////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
// Reference SHA256 Functions
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////

#define H0 0x6a09e667
#define H1 0xbb67ae85
#define H2 0x3c6ef372
#define H3 0xa54ff53a
#define H4 0x510e527f
#define H5 0x9b05688c
#define H6 0x1f83d9ab
#define H7 0x5be0cd19

#define ror32(x, r) (((x)>>(r)) ^ ((x)<<(32-(r))))
#define bswap(x) (((x)<<24) | (((x)&0xff00)<<8) | (((x)&0xff0000)>>8) | ((x)>>24))

#define W(x) w[(x) & 15]

#define S0(w) (ror32(w,7) ^ ror32(w,18) ^ (w >> 3))
#define S1(w) (ror32(w,17) ^ ror32(w,19) ^ (w >> 10))

#define s0(a) (ror32(a,2) ^ ror32(a,13) ^ ror32(a,22))
#define s1(e) (ror32(e,6) ^ ror32(e,11) ^ ror32(e,25))
#define maj(a,b,c) ((a & b) ^ (a & c) ^ (b & c))
#define ch(e,f,g) ((e & f) ^ (g & ~e))

#define step(i,a,b,c,d,e,f,g,h,k) \
	if (i<16) W(i) = bswap(ww[i]); \
	else \
	W(i) = W(i-16) + S0(W(i-15)) + W(i-7) + S1(W(i-2)); \
	t2 = s0(a) + maj(a,b,c); \
	t1 = h + s1(e) + ch(e,f,g) + k + W(i); \
	d += t1; \
	h = t1 + t2;

void sha256_single(const uint8_t * data, uint32_t digest[]);

void sha256_ref(const uint8_t * input_data, uint32_t * digest, const uint32_t len)
{
	uint32_t i, j;
	uint8_t buf[2 * SHA256_BLOCK_SIZE];
	union {
		uint64_t uint;
		uint8_t uchar[8];
	} convert;
	uint8_t *p;

	digest[0] = H0;
	digest[1] = H1;
	digest[2] = H2;
	digest[3] = H3;
	digest[4] = H4;
	digest[5] = H5;
	digest[6] = H6;
	digest[7] = H7;

	i = len;
	while (i >= SHA256_BLOCK_SIZE) {
		sha256_single(input_data, digest);
		input_data += SHA256_BLOCK_SIZE;
		i -= SHA256_BLOCK_SIZE;
	}

	memcpy(buf, input_data, i);
	buf[i++] = 0x80;
	for (j = i; j < ((2 * SHA256_BLOCK_SIZE) - SHA256_PADLENGTHFIELD_SIZE); j++)
		buf[j] = 0;

	if (i > SHA256_BLOCK_SIZE - SHA256_PADLENGTHFIELD_SIZE)
		i = 2 * SHA256_BLOCK_SIZE;
	else
		i = SHA256_BLOCK_SIZE;

	convert.uint = 8 * len;
	p = buf + i - 8;
	p[0] = convert.uchar[7];
	p[1] = convert.uchar[6];
	p[2] = convert.uchar[5];
	p[3] = convert.uchar[4];
	p[4] = convert.uchar[3];
	p[5] = convert.uchar[2];
	p[6] = convert.uchar[1];
	p[7] = convert.uchar[0];

	sha256_single(buf, digest);
	if (i == 2 * SHA256_BLOCK_SIZE)
		sha256_single(buf + SHA256_BLOCK_SIZE, digest);
}

void sha256_single(const uint8_t * data, uint32_t digest[])
{
	uint32_t a, b, c, d, e, f, g, h, t1, t2;
	uint32_t w[16];
	uint32_t *ww = (uint32_t *) data;

	a = digest[0];
	b = digest[1];
	c = digest[2];
	d = digest[3];
	e = digest[4];
	f = digest[5];
	g = digest[6];
	h = digest[7];

	step(0, a, b, c, d, e, f, g, h, 0x428a2f98);
	step(1, h, a, b, c, d, e, f, g, 0x71374491);
	step(2, g, h, a, b, c, d, e, f, 0xb5c0fbcf);
	step(3, f, g, h, a, b, c, d, e, 0xe9b5dba5);
	step(4, e, f, g, h, a, b, c, d, 0x3956c25b);
	step(5, d, e, f, g, h, a, b, c, 0x59f111f1);
	step(6, c, d, e, f, g, h, a, b, 0x923f82a4);
	step(7, b, c, d, e, f, g, h, a, 0xab1c5ed5);
	step(8, a, b, c, d, e, f, g, h, 0xd807aa98);
	step(9, h, a, b, c, d, e, f, g, 0x12835b01);
	step(10, g, h, a, b, c, d, e, f, 0x243185be);
	step(11, f, g, h, a, b, c, d, e, 0x550c7dc3);
	step(12, e, f, g, h, a, b, c, d, 0x72be5d74);
	step(13, d, e, f, g, h, a, b, c, 0x80deb1fe);
	step(14, c, d, e, f, g, h, a, b, 0x9bdc06a7);
	step(15, b, c, d, e, f, g, h, a, 0xc19bf174);
	step(16, a, b, c, d, e, f, g, h, 0xe49b69c1);
	step(17, h, a, b, c, d, e, f, g, 0xefbe4786);
	step(18, g, h, a, b, c, d, e, f, 0x0fc19dc6);
	step(19, f, g, h, a, b, c, d, e, 0x240ca1cc);
	step(20, e, f, g, h, a, b, c, d, 0x2de92c6f);
	step(21, d, e, f, g, h, a, b, c, 0x4a7484aa);
	step(22, c, d, e, f, g, h, a, b, 0x5cb0a9dc);
	step(23, b, c, d, e, f, g, h, a, 0x76f988da);
	step(24, a, b, c, d, e, f, g, h, 0x983e5152);
	step(25, h, a, b, c, d, e, f, g, 0xa831c66d);
	step(26, g, h, a, b, c, d, e, f, 0xb00327c8);
	step(27, f, g, h, a, b, c, d, e, 0xbf597fc7);
	step(28, e, f, g, h, a, b, c, d, 0xc6e00bf3);
	step(29, d, e, f, g, h, a, b, c, 0xd5a79147);
	step(30, c, d, e, f, g, h, a, b, 0x06ca6351);
	step(31, b, c, d, e, f, g, h, a, 0x14292967);
	step(32, a, b, c, d, e, f, g, h, 0x27b70a85);
	step(33, h, a, b, c, d, e, f, g, 0x2e1b2138);
	step(34, g, h, a, b, c, d, e, f, 0x4d2c6dfc);
	step(35, f, g, h, a, b, c, d, e, 0x53380d13);
	step(36, e, f, g, h, a, b, c, d, 0x650a7354);
	step(37, d, e, f, g, h, a, b, c, 0x766a0abb);
	step(38, c, d, e, f, g, h, a, b, 0x81c2c92e);
	step(39, b, c, d, e, f, g, h, a, 0x92722c85);
	step(40, a, b, c, d, e, f, g, h, 0xa2bfe8a1);
	step(41, h, a, b, c, d, e, f, g, 0xa81a664b);
	step(42, g, h, a, b, c, d, e, f, 0xc24b8b70);
	step(43, f, g, h, a, b, c, d, e, 0xc76c51a3);
	step(44, e, f, g, h, a, b, c, d, 0xd192e819);
	step(45, d, e, f, g, h, a, b, c, 0xd6990624);
	step(46, c, d, e, f, g, h, a, b, 0xf40e3585);
	step(47, b, c, d, e, f, g, h, a, 0x106aa070);
	step(48, a, b, c, d, e, f, g, h, 0x19a4c116);
	step(49, h, a, b, c, d, e, f, g, 0x1e376c08);
	step(50, g, h, a, b, c, d, e, f, 0x2748774c);
	step(51, f, g, h, a, b, c, d, e, 0x34b0bcb5);
	step(52, e, f, g, h, a, b, c, d, 0x391c0cb3);
	step(53, d, e, f, g, h, a, b, c, 0x4ed8aa4a);
	step(54, c, d, e, f, g, h, a, b, 0x5b9cca4f);
	step(55, b, c, d, e, f, g, h, a, 0x682e6ff3);
	step(56, a, b, c, d, e, f, g, h, 0x748f82ee);
	step(57, h, a, b, c, d, e, f, g, 0x78a5636f);
	step(58, g, h, a, b, c, d, e, f, 0x84c87814);
	step(59, f, g, h, a, b, c, d, e, 0x8cc70208);
	step(60, e, f, g, h, a, b, c, d, 0x90befffa);
	step(61, d, e, f, g, h, a, b, c, 0xa4506ceb);
	step(62, c, d, e, f, g, h, a, b, 0xbef9a3f7);
	step(63, b, c, d, e, f, g, h, a, 0xc67178f2);

	digest[0] += a;
	digest[1] += b;
	digest[2] += c;
	digest[3] += d;
	digest[4] += e;
	digest[5] += f;
	digest[6] += g;
	digest[7] += h;
}