+++ /dev/null
-// 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.
-
-// This is a C++ header-only implementation of Grisu2 algorithm from the publication:
-// Loitsch, Florian. "Printing floating-point numbers quickly and accurately with
-// integers." ACM Sigplan Notices 45.6 (2010): 233-243.
-
-#ifndef RAPIDJSON_DTOA_
-#define RAPIDJSON_DTOA_
-
-#include "itoa.h" // GetDigitsLut()
-#include "diyfp.h"
-#include "ieee754.h"
-
-RAPIDJSON_NAMESPACE_BEGIN
-namespace internal {
-
-#ifdef __GNUC__
-RAPIDJSON_DIAG_PUSH
-RAPIDJSON_DIAG_OFF(effc++)
-RAPIDJSON_DIAG_OFF(array-bounds) // some gcc versions generate wrong warnings https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59124
-#endif
-
-inline void GrisuRound(char* buffer, int len, uint64_t delta, uint64_t rest, uint64_t ten_kappa, uint64_t wp_w) {
- while (rest < wp_w && delta - rest >= ten_kappa &&
- (rest + ten_kappa < wp_w || /// closer
- wp_w - rest > rest + ten_kappa - wp_w)) {
- buffer[len - 1]--;
- rest += ten_kappa;
- }
-}
-
-inline unsigned CountDecimalDigit32(uint32_t n) {
- // Simple pure C++ implementation was faster than __builtin_clz version in this situation.
- if (n < 10) return 1;
- if (n < 100) return 2;
- if (n < 1000) return 3;
- if (n < 10000) return 4;
- if (n < 100000) return 5;
- if (n < 1000000) return 6;
- if (n < 10000000) return 7;
- if (n < 100000000) return 8;
- // Will not reach 10 digits in DigitGen()
- //if (n < 1000000000) return 9;
- //return 10;
- return 9;
-}
-
-inline void DigitGen(const DiyFp& W, const DiyFp& Mp, uint64_t delta, char* buffer, int* len, int* K) {
- static const uint32_t kPow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 };
- const DiyFp one(uint64_t(1) << -Mp.e, Mp.e);
- const DiyFp wp_w = Mp - W;
- uint32_t p1 = static_cast<uint32_t>(Mp.f >> -one.e);
- uint64_t p2 = Mp.f & (one.f - 1);
- unsigned kappa = CountDecimalDigit32(p1); // kappa in [0, 9]
- *len = 0;
-
- while (kappa > 0) {
- uint32_t d = 0;
- switch (kappa) {
- case 9: d = p1 / 100000000; p1 %= 100000000; break;
- case 8: d = p1 / 10000000; p1 %= 10000000; break;
- case 7: d = p1 / 1000000; p1 %= 1000000; break;
- case 6: d = p1 / 100000; p1 %= 100000; break;
- case 5: d = p1 / 10000; p1 %= 10000; break;
- case 4: d = p1 / 1000; p1 %= 1000; break;
- case 3: d = p1 / 100; p1 %= 100; break;
- case 2: d = p1 / 10; p1 %= 10; break;
- case 1: d = p1; p1 = 0; break;
- default:;
- }
- if (d || *len)
- buffer[(*len)++] = static_cast<char>('0' + static_cast<char>(d));
- kappa--;
- uint64_t tmp = (static_cast<uint64_t>(p1) << -one.e) + p2;
- if (tmp <= delta) {
- *K += kappa;
- GrisuRound(buffer, *len, delta, tmp, static_cast<uint64_t>(kPow10[kappa]) << -one.e, wp_w.f);
- return;
- }
- }
-
- // kappa = 0
- for (;;) {
- p2 *= 10;
- delta *= 10;
- char d = static_cast<char>(p2 >> -one.e);
- if (d || *len)
- buffer[(*len)++] = static_cast<char>('0' + d);
- p2 &= one.f - 1;
- kappa--;
- if (p2 < delta) {
- *K += kappa;
- int index = -static_cast<int>(kappa);
- GrisuRound(buffer, *len, delta, p2, one.f, wp_w.f * (index < 9 ? kPow10[-static_cast<int>(kappa)] : 0));
- return;
- }
- }
-}
-
-inline void Grisu2(double value, char* buffer, int* length, int* K) {
- const DiyFp v(value);
- DiyFp w_m, w_p;
- v.NormalizedBoundaries(&w_m, &w_p);
-
- const DiyFp c_mk = GetCachedPower(w_p.e, K);
- const DiyFp W = v.Normalize() * c_mk;
- DiyFp Wp = w_p * c_mk;
- DiyFp Wm = w_m * c_mk;
- Wm.f++;
- Wp.f--;
- DigitGen(W, Wp, Wp.f - Wm.f, buffer, length, K);
-}
-
-inline char* WriteExponent(int K, char* buffer) {
- if (K < 0) {
- *buffer++ = '-';
- K = -K;
- }
-
- if (K >= 100) {
- *buffer++ = static_cast<char>('0' + static_cast<char>(K / 100));
- K %= 100;
- const char* d = GetDigitsLut() + K * 2;
- *buffer++ = d[0];
- *buffer++ = d[1];
- }
- else if (K >= 10) {
- const char* d = GetDigitsLut() + K * 2;
- *buffer++ = d[0];
- *buffer++ = d[1];
- }
- else
- *buffer++ = static_cast<char>('0' + static_cast<char>(K));
-
- return buffer;
-}
-
-inline char* Prettify(char* buffer, int length, int k, int maxDecimalPlaces) {
- const int kk = length + k; // 10^(kk-1) <= v < 10^kk
-
- if (0 <= k && kk <= 21) {
- // 1234e7 -> 12340000000
- for (int i = length; i < kk; i++)
- buffer[i] = '0';
- buffer[kk] = '.';
- buffer[kk + 1] = '0';
- return &buffer[kk + 2];
- }
- else if (0 < kk && kk <= 21) {
- // 1234e-2 -> 12.34
- std::memmove(&buffer[kk + 1], &buffer[kk], static_cast<size_t>(length - kk));
- buffer[kk] = '.';
- if (0 > k + maxDecimalPlaces) {
- // When maxDecimalPlaces = 2, 1.2345 -> 1.23, 1.102 -> 1.1
- // Remove extra trailing zeros (at least one) after truncation.
- for (int i = kk + maxDecimalPlaces; i > kk + 1; i--)
- if (buffer[i] != '0')
- return &buffer[i + 1];
- return &buffer[kk + 2]; // Reserve one zero
- }
- else
- return &buffer[length + 1];
- }
- else if (-6 < kk && kk <= 0) {
- // 1234e-6 -> 0.001234
- const int offset = 2 - kk;
- std::memmove(&buffer[offset], &buffer[0], static_cast<size_t>(length));
- buffer[0] = '0';
- buffer[1] = '.';
- for (int i = 2; i < offset; i++)
- buffer[i] = '0';
- if (length - kk > maxDecimalPlaces) {
- // When maxDecimalPlaces = 2, 0.123 -> 0.12, 0.102 -> 0.1
- // Remove extra trailing zeros (at least one) after truncation.
- for (int i = maxDecimalPlaces + 1; i > 2; i--)
- if (buffer[i] != '0')
- return &buffer[i + 1];
- return &buffer[3]; // Reserve one zero
- }
- else
- return &buffer[length + offset];
- }
- else if (kk < -maxDecimalPlaces) {
- // Truncate to zero
- buffer[0] = '0';
- buffer[1] = '.';
- buffer[2] = '0';
- return &buffer[3];
- }
- else if (length == 1) {
- // 1e30
- buffer[1] = 'e';
- return WriteExponent(kk - 1, &buffer[2]);
- }
- else {
- // 1234e30 -> 1.234e33
- std::memmove(&buffer[2], &buffer[1], static_cast<size_t>(length - 1));
- buffer[1] = '.';
- buffer[length + 1] = 'e';
- return WriteExponent(kk - 1, &buffer[0 + length + 2]);
- }
-}
-
-inline char* dtoa(double value, char* buffer, int maxDecimalPlaces = 324) {
- RAPIDJSON_ASSERT(maxDecimalPlaces >= 1);
- Double d(value);
- if (d.IsZero()) {
- if (d.Sign())
- *buffer++ = '-'; // -0.0, Issue #289
- buffer[0] = '0';
- buffer[1] = '.';
- buffer[2] = '0';
- return &buffer[3];
- }
- else {
- if (value < 0) {
- *buffer++ = '-';
- value = -value;
- }
- int length, K;
- Grisu2(value, buffer, &length, &K);
- return Prettify(buffer, length, K, maxDecimalPlaces);
- }
-}
-
-#ifdef __GNUC__
-RAPIDJSON_DIAG_POP
-#endif
-
-} // namespace internal
-RAPIDJSON_NAMESPACE_END
-
-#endif // RAPIDJSON_DTOA_
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