// Copyright (c) 2014-2020, The Monero Project
// 
// 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.
// 
// 3. Neither the name of the copyright holder nor the names of its contributors may be
//    used to endorse or promote products derived from this software without specific
//    prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
// 
// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers

#include <cstddef>
#include <fstream>
#include <iomanip>
#include <ios>
#include <string>
#include <cfenv>

#include "misc_log_ex.h"
#include "warnings.h"
#include "crypto/hash.h"
#include "crypto/variant2_int_sqrt.h"
#include "../io.h"

using namespace std;
using namespace crypto;
typedef crypto::hash chash;

struct V4_Data
{
  const void* data;
  size_t length;
  uint64_t height;
};

PUSH_WARNINGS
DISABLE_VS_WARNINGS(4297)
extern "C" {
  static void hash_tree(const void *data, size_t length, char *hash) {
    if ((length & 31) != 0) {
      throw ios_base::failure("Invalid input length for tree_hash");
    }
    tree_hash((const char (*)[crypto::HASH_SIZE]) data, length >> 5, hash);
  }
  static void cn_slow_hash_0(const void *data, size_t length, char *hash) {
    return cn_slow_hash(data, length, hash, 0/*variant*/, 0/*prehashed*/, 0/*height*/);
  }
  static void cn_slow_hash_1(const void *data, size_t length, char *hash) {
    return cn_slow_hash(data, length, hash, 1/*variant*/, 0/*prehashed*/, 0/*height*/);
  }
  static void cn_slow_hash_2(const void *data, size_t length, char *hash) {
    return cn_slow_hash(data, length, hash, 2/*variant*/, 0/*prehashed*/, 0/*height*/);
  }
  static void cn_slow_hash_4(const void *data, size_t, char *hash) {
    const V4_Data* p = reinterpret_cast<const V4_Data*>(data);
    return cn_slow_hash(p->data, p->length, hash, 4/*variant*/, 0/*prehashed*/, p->height);
  }
}
POP_WARNINGS

extern "C" typedef void hash_f(const void *, size_t, char *);
struct hash_func {
  const string name;
  hash_f &f;
} hashes[] = {{"fast", cn_fast_hash}, {"slow", cn_slow_hash_0}, {"tree", hash_tree},
  {"extra-blake", hash_extra_blake}, {"extra-groestl", hash_extra_groestl},
  {"extra-jh", hash_extra_jh}, {"extra-skein", hash_extra_skein},
  {"slow-1", cn_slow_hash_1}, {"slow-2", cn_slow_hash_2}, {"slow-4", cn_slow_hash_4}};

int test_variant2_int_sqrt();
int test_variant2_int_sqrt_ref();

int main(int argc, char *argv[]) {
  TRY_ENTRY();

  hash_f *f;
  hash_func *hf;
  fstream input;
  vector<char> data;
  chash expected, actual;
  size_t test = 0;
  bool error = false;
  if (argc != 3) {
    if ((argc == 2) && (strcmp(argv[1], "variant2_int_sqrt") == 0)) {
      if (test_variant2_int_sqrt_ref() != 0) {
        return 1;
      }
      const int round_modes[3] = { FE_DOWNWARD, FE_TONEAREST, FE_UPWARD };
      for (int i = 0; i < 3; ++i) {
        std::fesetround(round_modes[i]);
        const int result = test_variant2_int_sqrt();
        if (result != 0) {
          cerr << "FPU round mode was set to ";
          switch (round_modes[i]) {
            case FE_DOWNWARD:
              cerr << "FE_DOWNWARD";
              break;
            case FE_TONEAREST:
              cerr << "FE_TONEAREST";
              break;
            case FE_UPWARD:
              cerr << "FE_UPWARD";
              break;
            default:
              cerr << "unknown";
              break;
          }
          cerr << endl;
          return result;
        }
      }
      return 0;
    }
    cerr << "Wrong number of arguments" << endl;
    return 1;
  }
  for (hf = hashes;; hf++) {
    if (hf >= &hashes[sizeof(hashes) / sizeof(hash_func)]) {
      cerr << "Unknown function" << endl;
      return 1;
    }
    if (argv[1] == hf->name) {
      f = &hf->f;
      break;
    }
  }
  input.open(argv[2], ios_base::in);
  for (;;) {
    ++test;
    input.exceptions(ios_base::badbit);
    get(input, expected);
    if (input.rdstate() & ios_base::eofbit) {
      break;
    }
    input.exceptions(ios_base::badbit | ios_base::failbit | ios_base::eofbit);
    input.clear(input.rdstate());
    get(input, data);
    if (f == cn_slow_hash_4) {
      V4_Data d;
      d.data = data.data();
      d.length = data.size();
      get(input, d.height);
      f(&d, 0, (char *) &actual);
    } else {
      f(data.data(), data.size(), (char *) &actual);
    }
    if (expected != actual) {
      size_t i;
      cerr << "Hash mismatch on test " << test << endl << "Input: ";
      if (data.size() == 0) {
        cerr << "empty";
      } else {
        for (i = 0; i < data.size(); i++) {
          cerr << setbase(16) << setw(2) << setfill('0') << int(static_cast<unsigned char>(data[i]));
        }
      }
      cerr << endl << "Expected hash: ";
      for (i = 0; i < 32; i++) {
          cerr << setbase(16) << setw(2) << setfill('0') << int(reinterpret_cast<unsigned char *>(&expected)[i]);
      }
      cerr << endl << "Actual hash: ";
      for (i = 0; i < 32; i++) {
          cerr << setbase(16) << setw(2) << setfill('0') << int(reinterpret_cast<unsigned char *>(&actual)[i]);
      }
      cerr << endl;
      error = true;
    }
  }
  return error ? 1 : 0;
  CATCH_ENTRY_L0("main", 1);
}

#if defined(__x86_64__) || (defined(_MSC_VER) && defined(_WIN64))

#include <emmintrin.h>

#if defined(_MSC_VER) || defined(__MINGW32__)
  #include <intrin.h>
#else
  #include <wmmintrin.h>
#endif

#endif

static inline bool test_variant2_int_sqrt_sse(const uint64_t sqrt_input, const uint64_t correct_result)
{
#if defined(__x86_64__) || (defined(_MSC_VER) && defined(_WIN64))
  uint64_t sqrt_result;
  VARIANT2_INTEGER_MATH_SQRT_STEP_SSE2();
  VARIANT2_INTEGER_MATH_SQRT_FIXUP(sqrt_result);
  if (sqrt_result != correct_result) {
    cerr << "Integer sqrt (SSE2 version) returned incorrect result for N = " << sqrt_input << endl;
    cerr << "Expected result: " << correct_result << endl;
    cerr << "Returned result: " << sqrt_result << endl;
    return false;
  }
#endif

  return true;
}

static inline bool test_variant2_int_sqrt_fp64(const uint64_t sqrt_input, const uint64_t correct_result)
{
#if defined DBL_MANT_DIG && (DBL_MANT_DIG >= 50)
  uint64_t sqrt_result;
  VARIANT2_INTEGER_MATH_SQRT_STEP_FP64();
  VARIANT2_INTEGER_MATH_SQRT_FIXUP(sqrt_result);
  if (sqrt_result != correct_result) {
    cerr << "Integer sqrt (FP64 version) returned incorrect result for N = " << sqrt_input << endl;
    cerr << "Expected result: " << correct_result << endl;
    cerr << "Returned result: " << sqrt_result << endl;
    return false;
  }
#endif

  return true;
}

static inline bool test_variant2_int_sqrt_ref(const uint64_t sqrt_input, const uint64_t correct_result)
{
  uint64_t sqrt_result;
  VARIANT2_INTEGER_MATH_SQRT_STEP_REF();
  if (sqrt_result != correct_result) {
    cerr << "Integer sqrt (reference version) returned incorrect result for N = " << sqrt_input << endl;
    cerr << "Expected result: " << correct_result << endl;
    cerr << "Returned result: " << sqrt_result << endl;
    return false;
  }

  return true;
}

static inline bool test_variant2_int_sqrt(const uint64_t sqrt_input, const uint64_t correct_result)
{
  if (!test_variant2_int_sqrt_sse(sqrt_input, correct_result)) {
    return false;
  }
  if (!test_variant2_int_sqrt_fp64(sqrt_input, correct_result)) {
    return false;
  }

  return true;
}

int test_variant2_int_sqrt()
{
  if (!test_variant2_int_sqrt(0, 0)) {
    return 1;
  }
  if (!test_variant2_int_sqrt(1ULL << 63, 1930543745UL)) {
    return 1;
  }
  if (!test_variant2_int_sqrt(uint64_t(-1), 3558067407UL)) {
    return 1;
  }

  for (uint64_t i = 1; i <= 3558067407UL; ++i) {
    // "i" is integer part of "sqrt(2^64 + n) * 2 - 2^33"
    // n = (i/2 + 2^32)^2 - 2^64

    const uint64_t i0 = i >> 1;
    uint64_t n1;
    if ((i & 1) == 0) {
      // n = (i/2 + 2^32)^2 - 2^64
      // n = i^2/4 + 2*2^32*i/2 + 2^64 - 2^64
      // n = i^2/4 + 2^32*i
      // i is even, so i^2 is divisible by 4:
      // n = (i^2 >> 2) + (i << 32)

      // int_sqrt_v2(i^2/4 + 2^32*i - 1) must be equal to i - 1
      // int_sqrt_v2(i^2/4 + 2^32*i) must be equal to i
      n1 = i0 * i0 + (i << 32) - 1;
    }
    else {
      // n = (i/2 + 2^32)^2 - 2^64
      // n = i^2/4 + 2*2^32*i/2 + 2^64 - 2^64
      // n = i^2/4 + 2^32*i
      // i is odd, so i = i0*2+1 (i0 = i >> 1)
      // n = (i0*2+1)^2/4 + 2^32*i
      // n = (i0^2*4+i0*4+1)/4 + 2^32*i
      // n = i0^2+i0+1/4 + 2^32*i
      // i0^2+i0 + 2^32*i < n < i0^2+i0+1 + 2^32*i

      // int_sqrt_v2(i0^2+i0 + 2^32*i) must be equal to i - 1
      // int_sqrt_v2(i0^2+i0+1 + 2^32*i) must be equal to i
      n1 = i0 * i0 + i0 + (i << 32);
    }

    if (!test_variant2_int_sqrt(n1, i - 1)) {
      return 1;
    }
    if (!test_variant2_int_sqrt(n1 + 1, i)) {
      return 1;
    }
  }

  return 0;
}

int test_variant2_int_sqrt_ref()
{
  if (!test_variant2_int_sqrt_ref(0, 0)) {
    return 1;
  }
  if (!test_variant2_int_sqrt_ref(1ULL << 63, 1930543745UL)) {
    return 1;
  }
  if (!test_variant2_int_sqrt_ref(uint64_t(-1), 3558067407UL)) {
    return 1;
  }

  // Reference version is slow, so we test only every 83th edge case
  // "i += 83" because 1 + 83 * 42868282 = 3558067407
  for (uint64_t i = 1; i <= 3558067407UL; i += 83) {
    const uint64_t i0 = i >> 1;
    uint64_t n1;
    if ((i & 1) == 0) {
      n1 = i0 * i0 + (i << 32) - 1;
    }
    else {
      n1 = i0 * i0 + i0 + (i << 32);
    }

    if (!test_variant2_int_sqrt_ref(n1, i - 1)) {
      return 1;
    }
    if (!test_variant2_int_sqrt_ref(n1 + 1, i)) {
      return 1;
    }
  }

  return 0;
}