/* Crypto/Sha256.c -- SHA-256 Hash
2015-11-14 : Igor Pavlov : Public domain
This code is based on public domain code from Wei Dai's Crypto++ library. */

#include "Precomp.h"

#include <string.h>

#include "CpuArch.h"
#include "RotateDefs.h"
#include "Sha256.h"

/* define it for speed optimization */
#ifndef _SFX
#define _SHA256_UNROLL
#define _SHA256_UNROLL2
#endif

/* #define _SHA256_UNROLL2 */

void Sha256_Init(CSha256* p)
{
    p->state[0] = 0x6a09e667;
    p->state[1] = 0xbb67ae85;
    p->state[2] = 0x3c6ef372;
    p->state[3] = 0xa54ff53a;
    p->state[4] = 0x510e527f;
    p->state[5] = 0x9b05688c;
    p->state[6] = 0x1f83d9ab;
    p->state[7] = 0x5be0cd19;
    p->count = 0;
}

#define S0(x) (rotrFixed(x, 2) ^ rotrFixed(x,13) ^ rotrFixed(x, 22))
#define S1(x) (rotrFixed(x, 6) ^ rotrFixed(x,11) ^ rotrFixed(x, 25))
#define s0(x) (rotrFixed(x, 7) ^ rotrFixed(x,18) ^ (x >> 3))
#define s1(x) (rotrFixed(x,17) ^ rotrFixed(x,19) ^ (x >> 10))

#define blk0(i) (W[i])
#define blk2(i) (W[i] += s1(W[((i)-2)&15]) + W[((i)-7)&15] + s0(W[((i)-15)&15]))

#define Ch(x,y,z) (z^(x&(y^z)))
#define Maj(x,y,z) ((x&y)|(z&(x|y)))

#ifdef _SHA256_UNROLL2

#define R(a,b,c,d,e,f,g,h, i) \
    h += S1(e) + Ch(e,f,g) + K[(i)+(j)] + (j ? blk2(i) : blk0(i)); \
    d += h; \
    h += S0(a) + Maj(a, b, c)

#define RX_8(i) \
  R(a,b,c,d,e,f,g,h, i); \
  R(h,a,b,c,d,e,f,g, i+1); \
  R(g,h,a,b,c,d,e,f, i+2); \
  R(f,g,h,a,b,c,d,e, i+3); \
  R(e,f,g,h,a,b,c,d, i+4); \
  R(d,e,f,g,h,a,b,c, i+5); \
  R(c,d,e,f,g,h,a,b, i+6); \
  R(b,c,d,e,f,g,h,a, i+7)

#define RX_16  RX_8(0); RX_8(8);

#else

#define a(i) T[(0-(i))&7]
#define b(i) T[(1-(i))&7]
#define c(i) T[(2-(i))&7]
#define d(i) T[(3-(i))&7]
#define e(i) T[(4-(i))&7]
#define f(i) T[(5-(i))&7]
#define g(i) T[(6-(i))&7]
#define h(i) T[(7-(i))&7]

#define R(i) \
    h(i) += S1(e(i)) + Ch(e(i),f(i),g(i)) + K[(i)+(j)] + (j ? blk2(i) : blk0(i)); \
    d(i) += h(i); \
    h(i) += S0(a(i)) + Maj(a(i), b(i), c(i)) \

#ifdef _SHA256_UNROLL

#define RX_8(i)  R(i+0); R(i+1); R(i+2); R(i+3); R(i+4); R(i+5); R(i+6); R(i+7);
#define RX_16  RX_8(0); RX_8(8);

#else

#define RX_16  unsigned i; for (i = 0; i < 16; i++) { R(i); }

#endif

#endif

static const UInt32 K[64] = {
  0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
  0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
  0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
  0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
  0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
  0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
  0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
  0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
  0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
  0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
  0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
  0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
  0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
  0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
  0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
  0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};

static void Sha256_WriteByteBlock(CSha256* p)
{
    UInt32 W[16];
    unsigned j;
    UInt32* state;

#ifdef _SHA256_UNROLL2
    UInt32 a, b, c, d, e, f, g, h;
#else
    UInt32 T[8];
#endif

    for (j = 0; j < 16; j += 4)
    {
        const Byte* ccc = p->buffer + j * 4;
        W[j] = GetBe32(ccc);
        W[j + 1] = GetBe32(ccc + 4);
        W[j + 2] = GetBe32(ccc + 8);
        W[j + 3] = GetBe32(ccc + 12);
    }

    state = p->state;

#ifdef _SHA256_UNROLL2
    a = state[0];
    b = state[1];
    c = state[2];
    d = state[3];
    e = state[4];
    f = state[5];
    g = state[6];
    h = state[7];
#else
    for (j = 0; j < 8; j++)
        T[j] = state[j];
#endif

    for (j = 0; j < 64; j += 16)
    {
        RX_16
    }

#ifdef _SHA256_UNROLL2
    state[0] += a;
    state[1] += b;
    state[2] += c;
    state[3] += d;
    state[4] += e;
    state[5] += f;
    state[6] += g;
    state[7] += h;
#else
    for (j = 0; j < 8; j++)
        state[j] += T[j];
#endif

    /* Wipe variables */
    /* memset(W, 0, sizeof(W)); */
    /* memset(T, 0, sizeof(T)); */
}

#undef S0
#undef S1
#undef s0
#undef s1

void Sha256_Update(CSha256* p, const Byte* data, size_t size)
{
    if (size == 0)
        return;

    {
        unsigned pos = (unsigned)p->count & 0x3F;
        unsigned num;

        p->count += size;

        num = 64 - pos;
        if (num > size)
        {
            memcpy(p->buffer + pos, data, size);
            return;
        }

        size -= num;
        memcpy(p->buffer + pos, data, num);
        data += num;
    }

    for (;;)
    {
        Sha256_WriteByteBlock(p);
        if (size < 64)
            break;
        size -= 64;
        memcpy(p->buffer, data, 64);
        data += 64;
    }

    if (size != 0)
        memcpy(p->buffer, data, size);
}

void Sha256_Final(CSha256* p, Byte* digest)
{
    unsigned pos = (unsigned)p->count & 0x3F;
    unsigned i;

    p->buffer[pos++] = 0x80;

    while (pos != (64 - 8))
    {
        pos &= 0x3F;
        if (pos == 0)
            Sha256_WriteByteBlock(p);
        p->buffer[pos++] = 0;
    }

    {
        UInt64 numBits = (p->count << 3);
        SetBe32(p->buffer + 64 - 8, (UInt32)(numBits >> 32));
        SetBe32(p->buffer + 64 - 4, (UInt32)(numBits));
    }

    Sha256_WriteByteBlock(p);

    for (i = 0; i < 8; i += 2)
    {
        UInt32 v0 = p->state[i];
        UInt32 v1 = p->state[i + 1];
        SetBe32(digest, v0);
        SetBe32(digest + 4, v1);
        digest += 8;
    }

    Sha256_Init(p);
}
