// 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_

namespace rapidjson {
	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
} // namespace rapidjson

#endif // RAPIDJSON_ITOA_
