/*-

 * Copyright 2021 Tarsnap Backup Inc.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include "php_hash.h"

#include "php_hash_sha.h"

#ifdef __SSE2__

# include <emmintrin.h>

/* Original implementation from libcperciva follows.

 *

 * Modified to use `PHP_STATIC_RESTRICT` for MSVC compatibility.

 */

/**

 * mm_bswap_epi32(a):

 * Byte-swap each 32-bit word.

 */

static inline __m128i

mm_bswap_epi32(__m128i a)

{

  /* Swap bytes in each 16-bit word. */

  a = _mm_or_si128(_mm_slli_epi16(a, 8), _mm_srli_epi16(a, 8));

  /* Swap all 16-bit words. */

  a = _mm_shufflelo_epi16(a, _MM_SHUFFLE(2, 3, 0, 1));

  a = _mm_shufflehi_epi16(a, _MM_SHUFFLE(2, 3, 0, 1));

  return (a);

}

/* SHA256 round constants. */

static const uint32_t Krnd[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

};

/* Elementary functions used by SHA256 */

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

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

#define ROTR(x, n)  ((x >> n) | (x << (32 - n)))

#define S0(x)   (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))

#define S1(x)   (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))

/* SHA256 round function */

#define RND(a, b, c, d, e, f, g, h, k)      \

  h += S1(e) + Ch(e, f, g) + k;      \

  d += h;           \

  h += S0(a) + Maj(a, b, c)

/* Adjusted round function for rotating state */

#define RNDr(S, W, i, ii)     \

  RND(S[(64 - i) % 8], S[(65 - i) % 8],  \

      S[(66 - i) % 8], S[(67 - i) % 8], \

      S[(68 - i) % 8], S[(69 - i) % 8], \

      S[(70 - i) % 8], S[(71 - i) % 8], \

      W[i + ii] + Krnd[i + ii])

/* Message schedule computation */

#define SHR32(x, n) (_mm_srli_epi32(x, n))

#define ROTR32(x, n) (_mm_or_si128(SHR32(x, n), _mm_slli_epi32(x, (32-n))))

#define s0_128(x) _mm_xor_si128(_mm_xor_si128(      \

  ROTR32(x, 7), ROTR32(x, 18)), SHR32(x, 3))

static inline __m128i

s1_128_high(__m128i a)

{

  __m128i b;

  __m128i c;

  /* ROTR, loading data as {B, B, A, A}; lanes 1 & 3 will be junk. */

  b = _mm_shuffle_epi32(a, _MM_SHUFFLE(1, 1, 0, 0));

  c = _mm_xor_si128(_mm_srli_epi64(b, 17), _mm_srli_epi64(b, 19));

  /* Shift and XOR with rotated data; lanes 1 & 3 will be junk. */

  c = _mm_xor_si128(c, _mm_srli_epi32(b, 10));

  /* Shuffle good data back and zero unwanted lanes. */

  c = _mm_shuffle_epi32(c, _MM_SHUFFLE(2, 0, 2, 0));

  c = _mm_slli_si128(c, 8);

  return (c);

}

static inline __m128i

s1_128_low(__m128i a)

{

  __m128i b;

  __m128i c;

  /* ROTR, loading data as {B, B, A, A}; lanes 1 & 3 will be junk. */

  b = _mm_shuffle_epi32(a, _MM_SHUFFLE(3, 3, 2, 2));

  c = _mm_xor_si128(_mm_srli_epi64(b, 17), _mm_srli_epi64(b, 19));

  /* Shift and XOR with rotated data; lanes 1 & 3 will be junk. */

  c = _mm_xor_si128(c, _mm_srli_epi32(b, 10));

  /* Shuffle good data back and zero unwanted lanes. */

  c = _mm_shuffle_epi32(c, _MM_SHUFFLE(2, 0, 2, 0));

  c = _mm_srli_si128(c, 8);

  return (c);

}

/**

 * SPAN_ONE_THREE(a, b):

 * Combine the upper three words of ${a} with the lowest word of ${b}.  This

 * could also be thought of returning bits [159:32] of the 256-bit value

 * consisting of (b[127:0] a[127:0]).  In other words, set:

 *     dst[31:0] := a[63:32]

 *     dst[63:32] := a[95:64]

 *     dst[95:64] := a[127:96]

 *     dst[127:96] := b[31:0]

 */

#define SPAN_ONE_THREE(a, b) (_mm_shuffle_epi32(_mm_castps_si128(  \

  _mm_move_ss(_mm_castsi128_ps(a), _mm_castsi128_ps(b))),   \

  _MM_SHUFFLE(0, 3, 2, 1)))

/**

 * MSG4(X0, X1, X2, X3):

 * Calculate the next four values of the message schedule.  If we define

 * ${W[j]} as the first unknown value in the message schedule, then the input

 * arguments are:

 *     X0 = W[j - 16] : W[j - 13]

 *     X1 = W[j - 12] : W[j - 9]

 *     X2 = W[j - 8] : W[j - 5]

 *     X3 = W[j - 4] : W[j - 1]

 * This function therefore calculates:

 *     X4 = W[j + 0] : W[j + 3]

 */

static inline __m128i

MSG4(__m128i X0, __m128i X1, __m128i X2, __m128i X3)

{

  __m128i X4;

  __m128i Xj_minus_seven, Xj_minus_fifteen;

  /* Set up variables which span X values. */

  Xj_minus_seven = SPAN_ONE_THREE(X2, X3);

  Xj_minus_fifteen = SPAN_ONE_THREE(X0, X1);

  /* Begin computing X4. */

  X4 = _mm_add_epi32(X0, Xj_minus_seven);

  X4 = _mm_add_epi32(X4, s0_128(Xj_minus_fifteen));

  /* First half of s1. */

  X4 = _mm_add_epi32(X4, s1_128_low(X3));

  /* Second half of s1; this depends on the above value of X4. */

  X4 = _mm_add_epi32(X4, s1_128_high(X4));

  return (X4);

}

/**

 * SHA256_Transform_sse2(state, block, W, S):

 * Compute the SHA256 block compression function, transforming ${state} using

 * the data in ${block}.  This implementation uses x86 SSE2 instructions, and

 * should only be used if _SSE2 is defined and cpusupport_x86_sse2() returns

 * nonzero.  The arrays W and S may be filled with sensitive data, and should

 * be cleared by the callee.

 */

void

SHA256_Transform_sse2(uint32_t state[PHP_STATIC_RESTRICT 8],

    const uint8_t block[PHP_STATIC_RESTRICT 64], uint32_t W[PHP_STATIC_RESTRICT 64],

    uint32_t S[PHP_STATIC_RESTRICT 8])

{

  __m128i Y[4];

  int i;

  /* 1. Prepare the first part of the message schedule W. */

  Y[0] = mm_bswap_epi32(_mm_loadu_si128((const __m128i *)&block[0]));

  _mm_storeu_si128((__m128i *)&W[0], Y[0]);

  Y[1] = mm_bswap_epi32(_mm_loadu_si128((const __m128i *)&block[16]));

  _mm_storeu_si128((__m128i *)&W[4], Y[1]);

  Y[2] = mm_bswap_epi32(_mm_loadu_si128((const __m128i *)&block[32]));

  _mm_storeu_si128((__m128i *)&W[8], Y[2]);

  Y[3] = mm_bswap_epi32(_mm_loadu_si128((const __m128i *)&block[48]));

  _mm_storeu_si128((__m128i *)&W[12], Y[3]);

  /* 2. Initialize working variables. */

  memcpy(S, state, 32);

  /* 3. Mix. */

  for (i = 0; i < 64; i += 16) {

    RNDr(S, W, 0, i);

    RNDr(S, W, 1, i);

    RNDr(S, W, 2, i);

    RNDr(S, W, 3, i);

    RNDr(S, W, 4, i);

    RNDr(S, W, 5, i);

    RNDr(S, W, 6, i);

    RNDr(S, W, 7, i);

    RNDr(S, W, 8, i);

    RNDr(S, W, 9, i);

    RNDr(S, W, 10, i);

    RNDr(S, W, 11, i);

    RNDr(S, W, 12, i);

    RNDr(S, W, 13, i);

    RNDr(S, W, 14, i);

    RNDr(S, W, 15, i);

    if (i == 48)

      break;

    Y[0] = MSG4(Y[0], Y[1], Y[2], Y[3]);

    _mm_storeu_si128((__m128i *)&W[16 + i + 0], Y[0]);

    Y[1] = MSG4(Y[1], Y[2], Y[3], Y[0]);

    _mm_storeu_si128((__m128i *)&W[16 + i + 4], Y[1]);

    Y[2] = MSG4(Y[2], Y[3], Y[0], Y[1]);

    _mm_storeu_si128((__m128i *)&W[16 + i + 8], Y[2]);

    Y[3] = MSG4(Y[3], Y[0], Y[1], Y[2]);

    _mm_storeu_si128((__m128i *)&W[16 + i + 12], Y[3]);

  }

  /* 4. Mix local working variables into global state. */

  for (i = 0; i < 8; i++)

    state[i] += S[i];

}

#endif