diff options
Diffstat (limited to '3rdparty/rapidjson/include/rapidjson/internal/strtod.h')
-rw-r--r-- | 3rdparty/rapidjson/include/rapidjson/internal/strtod.h | 122 |
1 files changed, 73 insertions, 49 deletions
diff --git a/3rdparty/rapidjson/include/rapidjson/internal/strtod.h b/3rdparty/rapidjson/include/rapidjson/internal/strtod.h index 289c413b07b..55f0e380bfa 100644 --- a/3rdparty/rapidjson/include/rapidjson/internal/strtod.h +++ b/3rdparty/rapidjson/include/rapidjson/internal/strtod.h @@ -1,6 +1,6 @@ // 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. +// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. // // 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 @@ -19,6 +19,8 @@ #include "biginteger.h" #include "diyfp.h" #include "pow10.h" +#include <climits> +#include <limits> RAPIDJSON_NAMESPACE_BEGIN namespace internal { @@ -126,46 +128,47 @@ inline bool StrtodFast(double d, int p, double* result) { } // Compute an approximation and see if it is within 1/2 ULP -inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosition, int exp, double* result) { +template<typename Ch> +inline bool StrtodDiyFp(const Ch* decimals, int dLen, int dExp, double* result) { uint64_t significand = 0; - size_t i = 0; // 2^64 - 1 = 18446744073709551615, 1844674407370955161 = 0x1999999999999999 - for (; i < length; i++) { + int i = 0; // 2^64 - 1 = 18446744073709551615, 1844674407370955161 = 0x1999999999999999 + for (; i < dLen; i++) { if (significand > RAPIDJSON_UINT64_C2(0x19999999, 0x99999999) || - (significand == RAPIDJSON_UINT64_C2(0x19999999, 0x99999999) && decimals[i] > '5')) + (significand == RAPIDJSON_UINT64_C2(0x19999999, 0x99999999) && decimals[i] > Ch('5'))) break; - significand = significand * 10u + static_cast<unsigned>(decimals[i] - '0'); + significand = significand * 10u + static_cast<unsigned>(decimals[i] - Ch('0')); } - if (i < length && decimals[i] >= '5') // Rounding + if (i < dLen && decimals[i] >= Ch('5')) // Rounding significand++; - size_t remaining = length - i; - const unsigned kUlpShift = 3; - const unsigned kUlp = 1 << kUlpShift; + int remaining = dLen - i; + const int kUlpShift = 3; + const int kUlp = 1 << kUlpShift; int64_t error = (remaining == 0) ? 0 : kUlp / 2; DiyFp v(significand, 0); v = v.Normalize(); error <<= -v.e; - const int dExp = static_cast<int>(decimalPosition) - static_cast<int>(i) + exp; + dExp += remaining; int actualExp; DiyFp cachedPower = GetCachedPower10(dExp, &actualExp); if (actualExp != dExp) { static const DiyFp kPow10[] = { - DiyFp(RAPIDJSON_UINT64_C2(0xa0000000, 00000000), -60), // 10^1 - DiyFp(RAPIDJSON_UINT64_C2(0xc8000000, 00000000), -57), // 10^2 - DiyFp(RAPIDJSON_UINT64_C2(0xfa000000, 00000000), -54), // 10^3 - DiyFp(RAPIDJSON_UINT64_C2(0x9c400000, 00000000), -50), // 10^4 - DiyFp(RAPIDJSON_UINT64_C2(0xc3500000, 00000000), -47), // 10^5 - DiyFp(RAPIDJSON_UINT64_C2(0xf4240000, 00000000), -44), // 10^6 - DiyFp(RAPIDJSON_UINT64_C2(0x98968000, 00000000), -40) // 10^7 + DiyFp(RAPIDJSON_UINT64_C2(0xa0000000, 0x00000000), -60), // 10^1 + DiyFp(RAPIDJSON_UINT64_C2(0xc8000000, 0x00000000), -57), // 10^2 + DiyFp(RAPIDJSON_UINT64_C2(0xfa000000, 0x00000000), -54), // 10^3 + DiyFp(RAPIDJSON_UINT64_C2(0x9c400000, 0x00000000), -50), // 10^4 + DiyFp(RAPIDJSON_UINT64_C2(0xc3500000, 0x00000000), -47), // 10^5 + DiyFp(RAPIDJSON_UINT64_C2(0xf4240000, 0x00000000), -44), // 10^6 + DiyFp(RAPIDJSON_UINT64_C2(0x98968000, 0x00000000), -40) // 10^7 }; - int adjustment = dExp - actualExp - 1; - RAPIDJSON_ASSERT(adjustment >= 0 && adjustment < 7); - v = v * kPow10[adjustment]; - if (length + static_cast<unsigned>(adjustment)> 19u) // has more digits than decimal digits in 64-bit + int adjustment = dExp - actualExp; + RAPIDJSON_ASSERT(adjustment >= 1 && adjustment < 8); + v = v * kPow10[adjustment - 1]; + if (dLen + adjustment > 19) // has more digits than decimal digits in 64-bit error += kUlp / 2; } @@ -177,17 +180,17 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit v = v.Normalize(); error <<= oldExp - v.e; - const unsigned effectiveSignificandSize = Double::EffectiveSignificandSize(64 + v.e); - unsigned precisionSize = 64 - effectiveSignificandSize; + const int effectiveSignificandSize = Double::EffectiveSignificandSize(64 + v.e); + int precisionSize = 64 - effectiveSignificandSize; if (precisionSize + kUlpShift >= 64) { - unsigned scaleExp = (precisionSize + kUlpShift) - 63; + int scaleExp = (precisionSize + kUlpShift) - 63; v.f >>= scaleExp; v.e += scaleExp; - error = (error >> scaleExp) + 1 + static_cast<int>(kUlp); + error = (error >> scaleExp) + 1 + kUlp; precisionSize -= scaleExp; } - DiyFp rounded(v.f >> precisionSize, v.e + static_cast<int>(precisionSize)); + DiyFp rounded(v.f >> precisionSize, v.e + precisionSize); const uint64_t precisionBits = (v.f & ((uint64_t(1) << precisionSize) - 1)) * kUlp; const uint64_t halfWay = (uint64_t(1) << (precisionSize - 1)) * kUlp; if (precisionBits >= halfWay + static_cast<unsigned>(error)) { @@ -203,9 +206,10 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit return halfWay - static_cast<unsigned>(error) >= precisionBits || precisionBits >= halfWay + static_cast<unsigned>(error); } -inline double StrtodBigInteger(double approx, const char* decimals, size_t length, size_t decimalPosition, int exp) { - const BigInteger dInt(decimals, length); - const int dExp = static_cast<int>(decimalPosition) - static_cast<int>(length) + exp; +template<typename Ch> +inline double StrtodBigInteger(double approx, const Ch* decimals, int dLen, int dExp) { + RAPIDJSON_ASSERT(dLen >= 0); + const BigInteger dInt(decimals, static_cast<unsigned>(dLen)); Double a(approx); int cmp = CheckWithinHalfULP(a.Value(), dInt, dExp); if (cmp < 0) @@ -221,46 +225,66 @@ inline double StrtodBigInteger(double approx, const char* decimals, size_t lengt return a.NextPositiveDouble(); } -inline double StrtodFullPrecision(double d, int p, const char* decimals, size_t length, size_t decimalPosition, int exp) { +template<typename Ch> +inline double StrtodFullPrecision(double d, int p, const Ch* decimals, size_t length, size_t decimalPosition, int exp) { RAPIDJSON_ASSERT(d >= 0.0); RAPIDJSON_ASSERT(length >= 1); - double result; + double result = 0.0; if (StrtodFast(d, p, &result)) return result; + RAPIDJSON_ASSERT(length <= INT_MAX); + int dLen = static_cast<int>(length); + + RAPIDJSON_ASSERT(length >= decimalPosition); + RAPIDJSON_ASSERT(length - decimalPosition <= INT_MAX); + int dExpAdjust = static_cast<int>(length - decimalPosition); + + RAPIDJSON_ASSERT(exp >= INT_MIN + dExpAdjust); + int dExp = exp - dExpAdjust; + + // Make sure length+dExp does not overflow + RAPIDJSON_ASSERT(dExp <= INT_MAX - dLen); + // Trim leading zeros - while (*decimals == '0' && length > 1) { - length--; + while (dLen > 0 && *decimals == '0') { + dLen--; decimals++; - decimalPosition--; } // Trim trailing zeros - while (decimals[length - 1] == '0' && length > 1) { - length--; - decimalPosition--; - exp++; + while (dLen > 0 && decimals[dLen - 1] == '0') { + dLen--; + dExp++; + } + + if (dLen == 0) { // Buffer only contains zeros. + return 0.0; } // Trim right-most digits - const int kMaxDecimalDigit = 780; - if (static_cast<int>(length) > kMaxDecimalDigit) { - int delta = (static_cast<int>(length) - kMaxDecimalDigit); - exp += delta; - decimalPosition -= static_cast<unsigned>(delta); - length = kMaxDecimalDigit; + const int kMaxDecimalDigit = 767 + 1; + if (dLen > kMaxDecimalDigit) { + dExp += dLen - kMaxDecimalDigit; + dLen = kMaxDecimalDigit; } - // If too small, underflow to zero - if (int(length) + exp < -324) + // If too small, underflow to zero. + // Any x <= 10^-324 is interpreted as zero. + if (dLen + dExp <= -324) return 0.0; - if (StrtodDiyFp(decimals, length, decimalPosition, exp, &result)) + // If too large, overflow to infinity. + // Any x >= 10^309 is interpreted as +infinity. + if (dLen + dExp > 309) + return std::numeric_limits<double>::infinity(); + + if (StrtodDiyFp(decimals, dLen, dExp, &result)) return result; // Use approximation from StrtodDiyFp and make adjustment with BigInteger comparison - return StrtodBigInteger(result, decimals, length, decimalPosition, exp); + return StrtodBigInteger(result, decimals, dLen, dExp); } } // namespace internal |