/*
* MD5
* (C) 1999-2008 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/internal/md5.h>

#include <botan/internal/bit_ops.h>
#include <botan/internal/buffer_slicer.h>
#include <botan/internal/loadstor.h>
#include <botan/internal/rotate.h>

#include <array>

namespace Botan {
namespace {

/*
* MD5 FF Function
*/
template <size_t S>
inline void FF(uint32_t& A, uint32_t B, uint32_t C, uint32_t D, uint32_t M) {
   A += choose(B, C, D) + M;
   A = rotl<S>(A) + B;
}

/*
* MD5 GG Function
*/
template <size_t S>
inline void GG(uint32_t& A, uint32_t B, uint32_t C, uint32_t D, uint32_t M) {
   A += choose(D, B, C) + M;
   A = rotl<S>(A) + B;
}

/*
* MD5 HH Function
*/
template <size_t S>
inline void HH(uint32_t& A, uint32_t B, uint32_t C, uint32_t D, uint32_t M) {
   A += (B ^ C ^ D) + M;
   A = rotl<S>(A) + B;
}

/*
* MD5 II Function
*/
template <size_t S>
inline void II(uint32_t& A, uint32_t B, uint32_t C, uint32_t D, uint32_t M) {
   // This expr is choose(D, B ^ C, ~C), but that is slower
   A += (C ^ (B | ~D)) + M;
   A = rotl<S>(A) + B;
}

}  // namespace

/*
* MD5 Compression Function
*/
void MD5::compress_n(MD5::digest_type& digest, std::span<const uint8_t> input, size_t blocks) {
   uint32_t A = digest[0];
   uint32_t B = digest[1];
   uint32_t C = digest[2];
   uint32_t D = digest[3];
   std::array<uint32_t, 16> M{};

   BufferSlicer in(input);

   for(size_t i = 0; i != blocks; ++i) {
      load_le(M, in.take<block_bytes>());

      // clang-format off

      FF< 7>(A, B, C, D, M[ 0] + 0xD76AA478);
      FF<12>(D, A, B, C, M[ 1] + 0xE8C7B756);
      FF<17>(C, D, A, B, M[ 2] + 0x242070DB);
      FF<22>(B, C, D, A, M[ 3] + 0xC1BDCEEE);
      FF< 7>(A, B, C, D, M[ 4] + 0xF57C0FAF);
      FF<12>(D, A, B, C, M[ 5] + 0x4787C62A);
      FF<17>(C, D, A, B, M[ 6] + 0xA8304613);
      FF<22>(B, C, D, A, M[ 7] + 0xFD469501);
      FF< 7>(A, B, C, D, M[ 8] + 0x698098D8);
      FF<12>(D, A, B, C, M[ 9] + 0x8B44F7AF);
      FF<17>(C, D, A, B, M[10] + 0xFFFF5BB1);
      FF<22>(B, C, D, A, M[11] + 0x895CD7BE);
      FF< 7>(A, B, C, D, M[12] + 0x6B901122);
      FF<12>(D, A, B, C, M[13] + 0xFD987193);
      FF<17>(C, D, A, B, M[14] + 0xA679438E);
      FF<22>(B, C, D, A, M[15] + 0x49B40821);

      GG< 5>(A, B, C, D, M[ 1] + 0xF61E2562);
      GG< 9>(D, A, B, C, M[ 6] + 0xC040B340);
      GG<14>(C, D, A, B, M[11] + 0x265E5A51);
      GG<20>(B, C, D, A, M[ 0] + 0xE9B6C7AA);
      GG< 5>(A, B, C, D, M[ 5] + 0xD62F105D);
      GG< 9>(D, A, B, C, M[10] + 0x02441453);
      GG<14>(C, D, A, B, M[15] + 0xD8A1E681);
      GG<20>(B, C, D, A, M[ 4] + 0xE7D3FBC8);
      GG< 5>(A, B, C, D, M[ 9] + 0x21E1CDE6);
      GG< 9>(D, A, B, C, M[14] + 0xC33707D6);
      GG<14>(C, D, A, B, M[ 3] + 0xF4D50D87);
      GG<20>(B, C, D, A, M[ 8] + 0x455A14ED);
      GG< 5>(A, B, C, D, M[13] + 0xA9E3E905);
      GG< 9>(D, A, B, C, M[ 2] + 0xFCEFA3F8);
      GG<14>(C, D, A, B, M[ 7] + 0x676F02D9);
      GG<20>(B, C, D, A, M[12] + 0x8D2A4C8A);

      HH< 4>(A, B, C, D, M[ 5] + 0xFFFA3942);
      HH<11>(D, A, B, C, M[ 8] + 0x8771F681);
      HH<16>(C, D, A, B, M[11] + 0x6D9D6122);
      HH<23>(B, C, D, A, M[14] + 0xFDE5380C);
      HH< 4>(A, B, C, D, M[ 1] + 0xA4BEEA44);
      HH<11>(D, A, B, C, M[ 4] + 0x4BDECFA9);
      HH<16>(C, D, A, B, M[ 7] + 0xF6BB4B60);
      HH<23>(B, C, D, A, M[10] + 0xBEBFBC70);
      HH< 4>(A, B, C, D, M[13] + 0x289B7EC6);
      HH<11>(D, A, B, C, M[ 0] + 0xEAA127FA);
      HH<16>(C, D, A, B, M[ 3] + 0xD4EF3085);
      HH<23>(B, C, D, A, M[ 6] + 0x04881D05);
      HH< 4>(A, B, C, D, M[ 9] + 0xD9D4D039);
      HH<11>(D, A, B, C, M[12] + 0xE6DB99E5);
      HH<16>(C, D, A, B, M[15] + 0x1FA27CF8);
      HH<23>(B, C, D, A, M[ 2] + 0xC4AC5665);

      II< 6>(A, B, C, D, M[ 0] + 0xF4292244);
      II<10>(D, A, B, C, M[ 7] + 0x432AFF97);
      II<15>(C, D, A, B, M[14] + 0xAB9423A7);
      II<21>(B, C, D, A, M[ 5] + 0xFC93A039);
      II< 6>(A, B, C, D, M[12] + 0x655B59C3);
      II<10>(D, A, B, C, M[ 3] + 0x8F0CCC92);
      II<15>(C, D, A, B, M[10] + 0xFFEFF47D);
      II<21>(B, C, D, A, M[ 1] + 0x85845DD1);
      II< 6>(A, B, C, D, M[ 8] + 0x6FA87E4F);
      II<10>(D, A, B, C, M[15] + 0xFE2CE6E0);
      II<15>(C, D, A, B, M[ 6] + 0xA3014314);
      II<21>(B, C, D, A, M[13] + 0x4E0811A1);
      II< 6>(A, B, C, D, M[ 4] + 0xF7537E82);
      II<10>(D, A, B, C, M[11] + 0xBD3AF235);
      II<15>(C, D, A, B, M[ 2] + 0x2AD7D2BB);
      II<21>(B, C, D, A, M[ 9] + 0xEB86D391);

      // clang-format off

      A = (digest[0] += A);
      B = (digest[1] += B);
      C = (digest[2] += C);
      D = (digest[3] += D);
   }
}

void MD5::init(digest_type& digest) {
   digest.assign({0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476});
}

std::unique_ptr<HashFunction> MD5::new_object() const {
   return std::make_unique<MD5>();
}

std::unique_ptr<HashFunction> MD5::copy_state() const {
   return std::make_unique<MD5>(*this);
}

void MD5::add_data(std::span<const uint8_t> input) {
   m_md.update(input);
}

void MD5::final_result(std::span<uint8_t> output) {
   m_md.final(output);
}

}  // namespace Botan
