// Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <openssl/md4.h>

#include <stdlib.h>
#include <string.h>

#include <openssl/span.h>

#include "../fipsmodule/digest/md32_common.h"
#include "../internal.h"


uint8_t *MD4(const uint8_t *data, size_t len, uint8_t out[MD4_DIGEST_LENGTH]) {
  MD4_CTX ctx;
  MD4_Init(&ctx);
  MD4_Update(&ctx, data, len);
  MD4_Final(out, &ctx);

  return out;
}

// Implemented from RFC 1186 The MD4 Message-Digest Algorithm.

int MD4_Init(MD4_CTX *md4) {
  OPENSSL_memset(md4, 0, sizeof(MD4_CTX));
  md4->h[0] = 0x67452301UL;
  md4->h[1] = 0xefcdab89UL;
  md4->h[2] = 0x98badcfeUL;
  md4->h[3] = 0x10325476UL;
  return 1;
}

static void md4_block_data_order(uint32_t *state, const uint8_t *data,
                                 size_t num);

void MD4_Transform(MD4_CTX *c, const uint8_t data[MD4_CBLOCK]) {
  md4_block_data_order(c->h, data, 1);
}

namespace {
struct MD4Traits {
  using HashContext = MD4_CTX;
  static constexpr size_t kBlockSize = MD4_CBLOCK;
  static constexpr bool kLengthIsBigEndian = false;
  static void HashBlocks(uint32_t *state, const uint8_t *data,
                         size_t num_blocks) {
    md4_block_data_order(state, data, num_blocks);
  }
};
}  // namespace

int MD4_Update(MD4_CTX *c, const void *data, size_t len) {
  bssl::crypto_md32_update<MD4Traits>(
      c, bssl::Span(static_cast<const uint8_t *>(data), len));
  return 1;
}

int MD4_Final(uint8_t out[MD4_DIGEST_LENGTH], MD4_CTX *c) {
  bssl::crypto_md32_final<MD4Traits>(c);
  CRYPTO_store_u32_le(out, c->h[0]);
  CRYPTO_store_u32_le(out + 4, c->h[1]);
  CRYPTO_store_u32_le(out + 8, c->h[2]);
  CRYPTO_store_u32_le(out + 12, c->h[3]);
  return 1;
}

// As pointed out by Wei Dai <weidai@eskimo.com>, the above can be
// simplified to the code below.  Wei attributes these optimizations
// to Peter Gutmann's SHS code, and he attributes it to Rich Schroeppel.
#define F(b, c, d) ((((c) ^ (d)) & (b)) ^ (d))
#define G(b, c, d) (((b) & (c)) | ((b) & (d)) | ((c) & (d)))
#define H(b, c, d) ((b) ^ (c) ^ (d))

#define R0(a, b, c, d, k, s, t)            \
  do {                                     \
    (a) += ((k) + (t) + F((b), (c), (d))); \
    (a) = CRYPTO_rotl_u32(a, s);           \
  } while (0)

#define R1(a, b, c, d, k, s, t)            \
  do {                                     \
    (a) += ((k) + (t) + G((b), (c), (d))); \
    (a) = CRYPTO_rotl_u32(a, s);           \
  } while (0)

#define R2(a, b, c, d, k, s, t)            \
  do {                                     \
    (a) += ((k) + (t) + H((b), (c), (d))); \
    (a) = CRYPTO_rotl_u32(a, s);           \
  } while (0)

static void md4_block_data_order(uint32_t *state, const uint8_t *data,
                                 size_t num) {
  uint32_t A, B, C, D;
  uint32_t X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X12, X13, X14, X15;

  A = state[0];
  B = state[1];
  C = state[2];
  D = state[3];

  for (; num--;) {
    X0 = CRYPTO_load_u32_le(data);
    data += 4;
    X1 = CRYPTO_load_u32_le(data);
    data += 4;
    // Round 0
    R0(A, B, C, D, X0, 3, 0);
    X2 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(D, A, B, C, X1, 7, 0);
    X3 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(C, D, A, B, X2, 11, 0);
    X4 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(B, C, D, A, X3, 19, 0);
    X5 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(A, B, C, D, X4, 3, 0);
    X6 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(D, A, B, C, X5, 7, 0);
    X7 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(C, D, A, B, X6, 11, 0);
    X8 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(B, C, D, A, X7, 19, 0);
    X9 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(A, B, C, D, X8, 3, 0);
    X10 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(D, A, B, C, X9, 7, 0);
    X11 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(C, D, A, B, X10, 11, 0);
    X12 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(B, C, D, A, X11, 19, 0);
    X13 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(A, B, C, D, X12, 3, 0);
    X14 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(D, A, B, C, X13, 7, 0);
    X15 = CRYPTO_load_u32_le(data);
    data += 4;
    R0(C, D, A, B, X14, 11, 0);
    R0(B, C, D, A, X15, 19, 0);
    // Round 1
    R1(A, B, C, D, X0, 3, 0x5A827999L);
    R1(D, A, B, C, X4, 5, 0x5A827999L);
    R1(C, D, A, B, X8, 9, 0x5A827999L);
    R1(B, C, D, A, X12, 13, 0x5A827999L);
    R1(A, B, C, D, X1, 3, 0x5A827999L);
    R1(D, A, B, C, X5, 5, 0x5A827999L);
    R1(C, D, A, B, X9, 9, 0x5A827999L);
    R1(B, C, D, A, X13, 13, 0x5A827999L);
    R1(A, B, C, D, X2, 3, 0x5A827999L);
    R1(D, A, B, C, X6, 5, 0x5A827999L);
    R1(C, D, A, B, X10, 9, 0x5A827999L);
    R1(B, C, D, A, X14, 13, 0x5A827999L);
    R1(A, B, C, D, X3, 3, 0x5A827999L);
    R1(D, A, B, C, X7, 5, 0x5A827999L);
    R1(C, D, A, B, X11, 9, 0x5A827999L);
    R1(B, C, D, A, X15, 13, 0x5A827999L);
    // Round 2
    R2(A, B, C, D, X0, 3, 0x6ED9EBA1L);
    R2(D, A, B, C, X8, 9, 0x6ED9EBA1L);
    R2(C, D, A, B, X4, 11, 0x6ED9EBA1L);
    R2(B, C, D, A, X12, 15, 0x6ED9EBA1L);
    R2(A, B, C, D, X2, 3, 0x6ED9EBA1L);
    R2(D, A, B, C, X10, 9, 0x6ED9EBA1L);
    R2(C, D, A, B, X6, 11, 0x6ED9EBA1L);
    R2(B, C, D, A, X14, 15, 0x6ED9EBA1L);
    R2(A, B, C, D, X1, 3, 0x6ED9EBA1L);
    R2(D, A, B, C, X9, 9, 0x6ED9EBA1L);
    R2(C, D, A, B, X5, 11, 0x6ED9EBA1L);
    R2(B, C, D, A, X13, 15, 0x6ED9EBA1L);
    R2(A, B, C, D, X3, 3, 0x6ED9EBA1L);
    R2(D, A, B, C, X11, 9, 0x6ED9EBA1L);
    R2(C, D, A, B, X7, 11, 0x6ED9EBA1L);
    R2(B, C, D, A, X15, 15, 0x6ED9EBA1L);

    A = state[0] += A;
    B = state[1] += B;
    C = state[2] += C;
    D = state[3] += D;
  }
}