// Tencent is pleased to support the open source community by making RapidJSON available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// 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.

#ifndef RAPIDJSON_ITOA_
#define RAPIDJSON_ITOA_

#include "../rapidjson.h"

RAPIDJSON_NAMESPACE_BEGIN
namespace internal
{

inline const char* GetDigitsLut()
{ static const char cDigitsLut[200] =
  { '0','0','0','1','0','2','0','3','0','4','0','5','0','6','0','7','0','8','0','9',
    '1','0','1','1','1','2','1','3','1','4','1','5','1','6','1','7','1','8','1','9',
    '2','0','2','1','2','2','2','3','2','4','2','5','2','6','2','7','2','8','2','9',
    '3','0','3','1','3','2','3','3','3','4','3','5','3','6','3','7','3','8','3','9',
    '4','0','4','1','4','2','4','3','4','4','4','5','4','6','4','7','4','8','4','9',
    '5','0','5','1','5','2','5','3','5','4','5','5','5','6','5','7','5','8','5','9',
    '6','0','6','1','6','2','6','3','6','4','6','5','6','6','6','7','6','8','6','9',
    '7','0','7','1','7','2','7','3','7','4','7','5','7','6','7','7','7','8','7','9',
    '8','0','8','1','8','2','8','3','8','4','8','5','8','6','8','7','8','8','8','9',
    '9','0','9','1','9','2','9','3','9','4','9','5','9','6','9','7','9','8','9','9'
  };
  return cDigitsLut;
}

inline char* u32toa(uint32_t value, char* buffer)
{ const char* cDigitsLut = GetDigitsLut();

  if (value < 10000)
  { const uint32_t d1 = (value / 100) << 1;
    const uint32_t d2 = (value % 100) << 1;

    if (value >= 1000)
      *buffer++ = cDigitsLut[d1];
    if (value >= 100)
      *buffer++ = cDigitsLut[d1 + 1];
    if (value >= 10)
      *buffer++ = cDigitsLut[d2];
    *buffer++ = cDigitsLut[d2 + 1];
  }
  else if (value < 100000000)
  { // value = bbbbcccc
    const uint32_t b = value / 10000;
    const uint32_t c = value % 10000;

    const uint32_t d1 = (b / 100) << 1;
    const uint32_t d2 = (b % 100) << 1;

    const uint32_t d3 = (c / 100) << 1;
    const uint32_t d4 = (c % 100) << 1;

    if (value >= 10000000)
      *buffer++ = cDigitsLut[d1];
    if (value >= 1000000)
      *buffer++ = cDigitsLut[d1 + 1];
    if (value >= 100000)
      *buffer++ = cDigitsLut[d2];
    *buffer++ = cDigitsLut[d2 + 1];

    *buffer++ = cDigitsLut[d3];
    *buffer++ = cDigitsLut[d3 + 1];
    *buffer++ = cDigitsLut[d4];
    *buffer++ = cDigitsLut[d4 + 1];
  }
  else
  { // value = aabbbbcccc in decimal

    const uint32_t a = value / 100000000; // 1 to 42
    value %= 100000000;

    if (a >= 10)
    { const unsigned i = a << 1;
      *buffer++ = cDigitsLut[i];
      *buffer++ = cDigitsLut[i + 1];
    }
    else
      *buffer++ = static_cast<char>('0' + static_cast<char>(a));

    const uint32_t b = value / 10000; // 0 to 9999
    const uint32_t c = value % 10000; // 0 to 9999

    const uint32_t d1 = (b / 100) << 1;
    const uint32_t d2 = (b % 100) << 1;

    const uint32_t d3 = (c / 100) << 1;
    const uint32_t d4 = (c % 100) << 1;

    *buffer++ = cDigitsLut[d1];
    *buffer++ = cDigitsLut[d1 + 1];
    *buffer++ = cDigitsLut[d2];
    *buffer++ = cDigitsLut[d2 + 1];
    *buffer++ = cDigitsLut[d3];
    *buffer++ = cDigitsLut[d3 + 1];
    *buffer++ = cDigitsLut[d4];
    *buffer++ = cDigitsLut[d4 + 1];
  }
  return buffer;
}

inline char* i32toa(int32_t value, char* buffer)
{ uint32_t u = static_cast<uint32_t>(value);
  if (value < 0)
  { *buffer++ = '-';
    u = ~u + 1;
  }

  return u32toa(u, buffer);
}

inline char* u64toa(uint64_t value, char* buffer)
{ const char* cDigitsLut = GetDigitsLut();
  const uint64_t  kTen8 = 100000000;
  const uint64_t  kTen9 = kTen8 * 10;
  const uint64_t kTen10 = kTen8 * 100;
  const uint64_t kTen11 = kTen8 * 1000;
  const uint64_t kTen12 = kTen8 * 10000;
  const uint64_t kTen13 = kTen8 * 100000;
  const uint64_t kTen14 = kTen8 * 1000000;
  const uint64_t kTen15 = kTen8 * 10000000;
  const uint64_t kTen16 = kTen8 * kTen8;

  if (value < kTen8)
  { uint32_t v = static_cast<uint32_t>(value);
    if (v < 10000)
    { const uint32_t d1 = (v / 100) << 1;
      const uint32_t d2 = (v % 100) << 1;

      if (v >= 1000)
        *buffer++ = cDigitsLut[d1];
      if (v >= 100)
        *buffer++ = cDigitsLut[d1 + 1];
      if (v >= 10)
        *buffer++ = cDigitsLut[d2];
      *buffer++ = cDigitsLut[d2 + 1];
    }
    else
    { // value = bbbbcccc
      const uint32_t b = v / 10000;
      const uint32_t c = v % 10000;

      const uint32_t d1 = (b / 100) << 1;
      const uint32_t d2 = (b % 100) << 1;

      const uint32_t d3 = (c / 100) << 1;
      const uint32_t d4 = (c % 100) << 1;

      if (value >= 10000000)
        *buffer++ = cDigitsLut[d1];
      if (value >= 1000000)
        *buffer++ = cDigitsLut[d1 + 1];
      if (value >= 100000)
        *buffer++ = cDigitsLut[d2];
      *buffer++ = cDigitsLut[d2 + 1];

      *buffer++ = cDigitsLut[d3];
      *buffer++ = cDigitsLut[d3 + 1];
      *buffer++ = cDigitsLut[d4];
      *buffer++ = cDigitsLut[d4 + 1];
    }
  }
  else if (value < kTen16)
  { const uint32_t v0 = static_cast<uint32_t>(value / kTen8);
    const uint32_t v1 = static_cast<uint32_t>(value % kTen8);

    const uint32_t b0 = v0 / 10000;
    const uint32_t c0 = v0 % 10000;

    const uint32_t d1 = (b0 / 100) << 1;
    const uint32_t d2 = (b0 % 100) << 1;

    const uint32_t d3 = (c0 / 100) << 1;
    const uint32_t d4 = (c0 % 100) << 1;

    const uint32_t b1 = v1 / 10000;
    const uint32_t c1 = v1 % 10000;

    const uint32_t d5 = (b1 / 100) << 1;
    const uint32_t d6 = (b1 % 100) << 1;

    const uint32_t d7 = (c1 / 100) << 1;
    const uint32_t d8 = (c1 % 100) << 1;

    if (value >= kTen15)
      *buffer++ = cDigitsLut[d1];
    if (value >= kTen14)
      *buffer++ = cDigitsLut[d1 + 1];
    if (value >= kTen13)
      *buffer++ = cDigitsLut[d2];
    if (value >= kTen12)
      *buffer++ = cDigitsLut[d2 + 1];
    if (value >= kTen11)
      *buffer++ = cDigitsLut[d3];
    if (value >= kTen10)
      *buffer++ = cDigitsLut[d3 + 1];
    if (value >= kTen9)
      *buffer++ = cDigitsLut[d4];
    if (value >= kTen8)
      *buffer++ = cDigitsLut[d4 + 1];

    *buffer++ = cDigitsLut[d5];
    *buffer++ = cDigitsLut[d5 + 1];
    *buffer++ = cDigitsLut[d6];
    *buffer++ = cDigitsLut[d6 + 1];
    *buffer++ = cDigitsLut[d7];
    *buffer++ = cDigitsLut[d7 + 1];
    *buffer++ = cDigitsLut[d8];
    *buffer++ = cDigitsLut[d8 + 1];
  }
  else
  { const uint32_t a = static_cast<uint32_t>(value / kTen16); // 1 to 1844
    value %= kTen16;

    if (a < 10)
      *buffer++ = static_cast<char>('0' + static_cast<char>(a));
    else if (a < 100)
    { const uint32_t i = a << 1;
      *buffer++ = cDigitsLut[i];
      *buffer++ = cDigitsLut[i + 1];
    }
    else if (a < 1000)
    { *buffer++ = static_cast<char>('0' + static_cast<char>(a / 100));

      const uint32_t i = (a % 100) << 1;
      *buffer++ = cDigitsLut[i];
      *buffer++ = cDigitsLut[i + 1];
    }
    else
    { const uint32_t i = (a / 100) << 1;
      const uint32_t j = (a % 100) << 1;
      *buffer++ = cDigitsLut[i];
      *buffer++ = cDigitsLut[i + 1];
      *buffer++ = cDigitsLut[j];
      *buffer++ = cDigitsLut[j + 1];
    }

    const uint32_t v0 = static_cast<uint32_t>(value / kTen8);
    const uint32_t v1 = static_cast<uint32_t>(value % kTen8);

    const uint32_t b0 = v0 / 10000;
    const uint32_t c0 = v0 % 10000;

    const uint32_t d1 = (b0 / 100) << 1;
    const uint32_t d2 = (b0 % 100) << 1;

    const uint32_t d3 = (c0 / 100) << 1;
    const uint32_t d4 = (c0 % 100) << 1;

    const uint32_t b1 = v1 / 10000;
    const uint32_t c1 = v1 % 10000;

    const uint32_t d5 = (b1 / 100) << 1;
    const uint32_t d6 = (b1 % 100) << 1;

    const uint32_t d7 = (c1 / 100) << 1;
    const uint32_t d8 = (c1 % 100) << 1;

    *buffer++ = cDigitsLut[d1];
    *buffer++ = cDigitsLut[d1 + 1];
    *buffer++ = cDigitsLut[d2];
    *buffer++ = cDigitsLut[d2 + 1];
    *buffer++ = cDigitsLut[d3];
    *buffer++ = cDigitsLut[d3 + 1];
    *buffer++ = cDigitsLut[d4];
    *buffer++ = cDigitsLut[d4 + 1];
    *buffer++ = cDigitsLut[d5];
    *buffer++ = cDigitsLut[d5 + 1];
    *buffer++ = cDigitsLut[d6];
    *buffer++ = cDigitsLut[d6 + 1];
    *buffer++ = cDigitsLut[d7];
    *buffer++ = cDigitsLut[d7 + 1];
    *buffer++ = cDigitsLut[d8];
    *buffer++ = cDigitsLut[d8 + 1];
  }

  return buffer;
}

inline char* i64toa(int64_t value, char* buffer)
{ uint64_t u = static_cast<uint64_t>(value);
  if (value < 0)
  { *buffer++ = '-';
    u = ~u + 1;
  }

  return u64toa(u, buffer);
}

} // namespace internal
RAPIDJSON_NAMESPACE_END

#endif // RAPIDJSON_ITOA_
