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Merge a757a2a into 01c7174
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@abolz
abolz committed Jun 16, 2018
2 parents 01c7174 + a757a2a commit be06131
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Showing 6 changed files with 397 additions and 60 deletions.
2 changes: 1 addition & 1 deletion include/rapidjson/internal/biginteger.h
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Original file line number Diff line number Diff line change
Expand Up @@ -133,7 +133,7 @@ class BigInteger {
RAPIDJSON_ASSERT(count_ + offset <= kCapacity);

if (interShift == 0) {
std::memmove(&digits_[count_ - 1 + offset], &digits_[count_ - 1], count_ * sizeof(Type));
std::memmove(digits_ + offset, digits_, count_ * sizeof(Type));
count_ += offset;
}
else {
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34 changes: 23 additions & 11 deletions include/rapidjson/internal/diyfp.h
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Original file line number Diff line number Diff line change
@@ -1,15 +1,15 @@
// 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
// 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:
Expand All @@ -20,6 +20,7 @@
#define RAPIDJSON_DIYFP_H_

#include "../rapidjson.h"
#include <limits>

#if defined(_MSC_VER) && defined(_M_AMD64) && !defined(__INTEL_COMPILER)
#include <intrin.h>
Expand Down Expand Up @@ -56,7 +57,7 @@ struct DiyFp {
if (biased_e != 0) {
f = significand + kDpHiddenBit;
e = biased_e - kDpExponentBias;
}
}
else {
f = significand;
e = kDpMinExponent + 1;
Expand Down Expand Up @@ -141,7 +142,16 @@ struct DiyFp {
double d;
uint64_t u64;
}u;
const uint64_t be = (e == kDpDenormalExponent && (f & kDpHiddenBit) == 0) ? 0 :
RAPIDJSON_ASSERT(f <= kDpHiddenBit + kDpSignificandMask);
if (e < kDpDenormalExponent) {
// Underflow.
return 0.0;
}
if (e >= kDpMaxExponent) {
// Overflow.
return std::numeric_limits<double>::infinity();
}
const uint64_t be = (e == kDpDenormalExponent && (f & kDpHiddenBit) == 0) ? 0 :
static_cast<uint64_t>(e + kDpExponentBias);
u.u64 = (f & kDpSignificandMask) | (be << kDpSignificandSize);
return u.d;
Expand Down Expand Up @@ -220,9 +230,10 @@ inline DiyFp GetCachedPowerByIndex(size_t index) {
641, 667, 694, 720, 747, 774, 800, 827, 853, 880,
907, 933, 960, 986, 1013, 1039, 1066
};
RAPIDJSON_ASSERT(index < 87);
return DiyFp(kCachedPowers_F[index], kCachedPowers_E[index]);
}

inline DiyFp GetCachedPower(int e, int* K) {

//int k = static_cast<int>(ceil((-61 - e) * 0.30102999566398114)) + 374;
Expand All @@ -238,10 +249,11 @@ inline DiyFp GetCachedPower(int e, int* K) {
}

inline DiyFp GetCachedPower10(int exp, int *outExp) {
unsigned index = (static_cast<unsigned>(exp) + 348u) / 8u;
*outExp = -348 + static_cast<int>(index) * 8;
return GetCachedPowerByIndex(index);
}
RAPIDJSON_ASSERT(exp >= -348);
unsigned index = static_cast<unsigned>(exp + 348) / 8u;
*outExp = -348 + static_cast<int>(index) * 8;
return GetCachedPowerByIndex(index);
}

#ifdef __GNUC__
RAPIDJSON_DIAG_POP
Expand Down
97 changes: 59 additions & 38 deletions include/rapidjson/internal/strtod.h
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,8 @@
#include "biginteger.h"
#include "diyfp.h"
#include "pow10.h"
#include <climits>
#include <limits>

RAPIDJSON_NAMESPACE_BEGIN
namespace internal {
Expand Down Expand Up @@ -126,20 +128,20 @@ 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) {
inline bool StrtodDiyFp(const char* 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'))
break;
significand = significand * 10u + static_cast<unsigned>(decimals[i] - '0');
}

if (i < length && decimals[i] >= '5') // Rounding
if (i < dLen && decimals[i] >= '5') // Rounding
significand++;

size_t remaining = length - i;
int remaining = dLen - i;
const int kUlpShift = 3;
const int kUlp = 1 << kUlpShift;
int64_t error = (remaining == 0) ? 0 : kUlp / 2;
Expand All @@ -148,24 +150,24 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit
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;
}

Expand Down Expand Up @@ -203,9 +205,9 @@ 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;
inline double StrtodBigInteger(double approx, const char* 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)
Expand All @@ -225,42 +227,61 @@ inline double StrtodFullPrecision(double d, int p, const char* decimals, size_t
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
Expand Down
9 changes: 7 additions & 2 deletions include/rapidjson/reader.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1561,8 +1561,6 @@ class GenericReader {
// Force double for big integer
if (useDouble) {
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
if (RAPIDJSON_UNLIKELY(d >= 1.7976931348623157e307)) // DBL_MAX / 10.0
RAPIDJSON_PARSE_ERROR(kParseErrorNumberTooBig, startOffset);
d = d * 10 + (s.TakePush() - '0');
}
}
Expand Down Expand Up @@ -1702,6 +1700,13 @@ class GenericReader {
else
d = internal::StrtodNormalPrecision(d, p);

// Use > max, instead of == inf, to fix bogus warning -Wfloat-equal
if (d > std::numeric_limits<double>::max()) {
// Overflow
// TODO: internal::StrtodX should report overflow (or underflow)
RAPIDJSON_PARSE_ERROR(kParseErrorNumberTooBig, startOffset);
}

cont = handler.Double(minus ? -d : d);
}
else if (useNanOrInf) {
Expand Down
5 changes: 5 additions & 0 deletions test/unittest/bigintegertest.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -120,6 +120,11 @@ TEST(BigInteger, LeftShift) {
EXPECT_TRUE(BIGINTEGER_LITERAL("4537899042132549697536") == a);
a <<= 99;
EXPECT_TRUE(BIGINTEGER_LITERAL("2876235222267216943024851750785644982682875244576768") == a);

a = 1;
a <<= 64; // a.count_ != 1
a <<= 256; // interShift == 0
EXPECT_TRUE(BIGINTEGER_LITERAL("2135987035920910082395021706169552114602704522356652769947041607822219725780640550022962086936576") == a);
}

TEST(BigInteger, Compare) {
Expand Down

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