// Copyright (C) 2011 Milo Yip
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#ifndef RAPIDJSON_ITOA_
#define RAPIDJSON_ITOA_

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)
{
    if (value < 0)
    {
        *buffer++ = '-';
        value     = -value;
    }

    return u32toa(static_cast<uint32_t>(value), 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)
{
    if (value < 0)
    {
        *buffer++ = '-';
        value     = -value;
    }

    return u64toa(static_cast<uint64_t>(value), buffer);
}

}  // namespace internal
RAPIDJSON_NAMESPACE_END

#endif  // RAPIDJSON_ITOA_
