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Adapter alibaba fastjson to other json libraries. the fastjson version: 1.2.58
/*
* Copyright 2019 the original author or authors.
*
* Licensed under the Apache, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at http://www.gnu.org/licenses/lgpl-3.0.html
*
* 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.
*/
package com.alibaba.fastjson.util;
import java.math.BigInteger;
/**
* An implementation of Ryu for double.
*/
public final class RyuDouble {
private static final int[][] POW5_SPLIT = new int[326][4];
private static final int[][] POW5_INV_SPLIT = new int[291][4];
static {
BigInteger mask = BigInteger.ONE.shiftLeft(31).subtract(BigInteger.ONE);
BigInteger invMask = BigInteger.ONE.shiftLeft(31).subtract(BigInteger.ONE);
for (int i = 0; i < 326; i++) {
BigInteger pow = BigInteger.valueOf(5).pow(i);
int pow5len = pow.bitLength();
int expectedPow5Bits = i == 0 ? 1 : (int) ((i * 23219280L + 10000000L - 1) / 10000000L);
if (expectedPow5Bits != pow5len) {
throw new IllegalStateException(pow5len + " != " + expectedPow5Bits);
}
if (i < POW5_SPLIT.length) {
for (int j = 0; j < 4; j++) {
POW5_SPLIT[i][j] = pow
.shiftRight(pow5len - 121 + (3 - j) * 31)
.and(mask)
.intValue();
}
}
if (i < POW5_INV_SPLIT.length) {
// We want floor(log_2 5^q) here, which is pow5len - 1.
int j = pow5len + 121;
BigInteger inv = BigInteger.ONE
.shiftLeft(j)
.divide(pow)
.add(BigInteger.ONE);
for (int k = 0; k < 4; k++) {
if (k == 0) {
POW5_INV_SPLIT[i][k] = inv
.shiftRight((3 - k) * 31)
.intValue();
} else {
POW5_INV_SPLIT[i][k] = inv
.shiftRight((3 - k) * 31)
.and(invMask)
.intValue();
}
}
}
}
}
public static String toString(double value) {
char[] result = new char[24];
int len = toString(value, result, 0);
return new String(result, 0, len);
}
public static int toString(double value, char[] result, int off) {
final long DOUBLE_MANTISSA_MASK = 4503599627370495L; // (1L << 52) - 1;
final int DOUBLE_EXPONENT_MASK = 2047; // (1 << 11) - 1;
final int DOUBLE_EXPONENT_BIAS = 1023; // (1 << (11 - 1)) - 1;
final long LOG10_5_NUMERATOR = 6989700L; // (long) (10000000L * Math.log10(5));
final long LOG10_2_NUMERATOR = 3010299L; // (long) (10000000L * Math.log10(2));
// Step 1: Decode the floating point number, and unify normalized and subnormal cases.
// First, handle all the trivial cases.
int index = off;
if (Double.isNaN(value)) {
result[index++] = 'N';
result[index++] = 'a';
result[index++] = 'N';
return index - off;
}
if (value == Double.POSITIVE_INFINITY) {
result[index++] = 'I';
result[index++] = 'n';
result[index++] = 'f';
result[index++] = 'i';
result[index++] = 'n';
result[index++] = 'i';
result[index++] = 't';
result[index++] = 'y';
return index - off;
}
if (value == Double.NEGATIVE_INFINITY) {
result[index++] = '-';
result[index++] = 'I';
result[index++] = 'n';
result[index++] = 'f';
result[index++] = 'i';
result[index++] = 'n';
result[index++] = 'i';
result[index++] = 't';
result[index++] = 'y';
return index - off;
}
long bits = Double.doubleToLongBits(value);
if (bits == 0) {
result[index++] = '0';
result[index++] = '.';
result[index++] = '0';
return index - off;
}
if (bits == 0x8000000000000000L) {
result[index++] = '-';
result[index++] = '0';
result[index++] = '.';
result[index++] = '0';
return index - off;
}
final int DOUBLE_MANTISSA_BITS = 52;
// Otherwise extract the mantissa and exponent bits and run the full algorithm.
int ieeeExponent = (int) ((bits >>> DOUBLE_MANTISSA_BITS) & DOUBLE_EXPONENT_MASK);
long ieeeMantissa = bits & DOUBLE_MANTISSA_MASK;
int e2;
long m2;
if (ieeeExponent == 0) {
// Denormal number - no implicit leading 1, and the exponent is 1, not 0.
e2 = 1 - DOUBLE_EXPONENT_BIAS - DOUBLE_MANTISSA_BITS;
m2 = ieeeMantissa;
} else {
// Add implicit leading 1.
e2 = ieeeExponent - DOUBLE_EXPONENT_BIAS - DOUBLE_MANTISSA_BITS;
m2 = ieeeMantissa | (1L << DOUBLE_MANTISSA_BITS);
}
boolean sign = bits < 0;
// Step 2: Determine the interval of legal decimal representations.
boolean even = (m2 & 1) == 0;
final long mv = 4 * m2;
final long mp = 4 * m2 + 2;
final int mmShift = ((m2 != (1L << DOUBLE_MANTISSA_BITS)) || (ieeeExponent <= 1)) ? 1 : 0;
final long mm = 4 * m2 - 1 - mmShift;
e2 -= 2;
// Step 3: Convert to a decimal power base using 128-bit arithmetic.
// -1077 = 1 - 1023 - 53 - 2 <= e_2 - 2 <= 2046 - 1023 - 53 - 2 = 968
long dv, dp, dm;
final int e10;
boolean dmIsTrailingZeros = false, dvIsTrailingZeros = false;
if (e2 >= 0) {
final int q = Math.max(0, (int) (e2 * LOG10_2_NUMERATOR / 10000000L) - 1);
// k = constant + floor(log_2(5^q))
// q == 0 ? 1 : (int) ((q * 23219280L + 10000000L - 1) / 10000000L)
final int k = 122 + (q == 0 ? 1 : (int) ((q * 23219280L + 10000000L - 1) / 10000000L)) - 1;
final int i = -e2 + q + k;
int actualShift = i - 3 * 31 - 21;
if (actualShift < 0) {
throw new IllegalArgumentException("" + actualShift);
}
final int[] ints = POW5_INV_SPLIT[q];
{
long mHigh = mv >>> 31;
long mLow = mv & 0x7fffffff;
long bits13 = mHigh * ints[0];
long bits03 = mLow * ints[0];
long bits12 = mHigh * ints[1];
long bits02 = mLow * ints[1];
long bits11 = mHigh * ints[2];
long bits01 = mLow * ints[2];
long bits10 = mHigh * ints[3];
long bits00 = mLow * ints[3];
dv = ((((((
((bits00 >>> 31) + bits01 + bits10) >>> 31)
+ bits02 + bits11) >>> 31)
+ bits03 + bits12) >>> 21)
+ (bits13 << 10)) >>> actualShift;
}
{
long mHigh = mp >>> 31;
long mLow = mp & 0x7fffffff;
long bits13 = mHigh * ints[0];
long bits03 = mLow * ints[0];
long bits12 = mHigh * ints[1];
long bits02 = mLow * ints[1];
long bits11 = mHigh * ints[2];
long bits01 = mLow * ints[2];
long bits10 = mHigh * ints[3];
long bits00 = mLow * ints[3];
dp = ((((((
((bits00 >>> 31) + bits01 + bits10) >>> 31)
+ bits02 + bits11) >>> 31)
+ bits03 + bits12) >>> 21)
+ (bits13 << 10)) >>> actualShift;
}
{
long mHigh = mm >>> 31;
long mLow = mm & 0x7fffffff;
long bits13 = mHigh * ints[0];
long bits03 = mLow * ints[0];
long bits12 = mHigh * ints[1];
long bits02 = mLow * ints[1];
long bits11 = mHigh * ints[2];
long bits01 = mLow * ints[2];
long bits10 = mHigh * ints[3];
long bits00 = mLow * ints[3];
dm = ((((((
((bits00 >>> 31) + bits01 + bits10) >>> 31)
+ bits02 + bits11) >>> 31)
+ bits03 + bits12) >>> 21)
+ (bits13 << 10)) >>> actualShift;
}
e10 = q;
if (q <= 21) {
if (mv % 5 == 0) {
int pow5Factor_mv;
{
long v = mv;
if ((v % 5) != 0) {
pow5Factor_mv = 0;
} else if ((v % 25) != 0) {
pow5Factor_mv = 1;
} else if ((v % 125) != 0) {
pow5Factor_mv = 2;
} else if ((v % 625) != 0) {
pow5Factor_mv = 3;
} else {
pow5Factor_mv = 4;
v /= 625;
while (v > 0) {
if (v % 5 != 0) {
break;
}
v /= 5;
pow5Factor_mv++;
}
}
}
dvIsTrailingZeros = pow5Factor_mv >= q;
} else if (even) {
int pow5Factor_mm;
{
long v = mm;
if ((v % 5) != 0) {
pow5Factor_mm = 0;
} else if ((v % 25) != 0) {
pow5Factor_mm = 1;
} else if ((v % 125) != 0) {
pow5Factor_mm = 2;
} else if ((v % 625) != 0) {
pow5Factor_mm = 3;
} else {
pow5Factor_mm = 4;
v /= 625;
while (v > 0) {
if (v % 5 != 0) {
break;
}
v /= 5;
pow5Factor_mm++;
}
}
}
dmIsTrailingZeros = pow5Factor_mm >= q; //
} else {
int pow5Factor_mp;
{
long v = mp;
if ((v % 5) != 0) {
pow5Factor_mp = 0;
} else if ((v % 25) != 0) {
pow5Factor_mp = 1;
} else if ((v % 125) != 0) {
pow5Factor_mp = 2;
} else if ((v % 625) != 0) {
pow5Factor_mp = 3;
} else {
pow5Factor_mp = 4;
v /= 625;
while (v > 0) {
if (v % 5 != 0) {
break;
}
v /= 5;
pow5Factor_mp++;
}
}
}
if (pow5Factor_mp >= q) {
dp--;
}
}
}
} else {
final int q = Math.max(0, (int) (-e2 * LOG10_5_NUMERATOR / 10000000L) - 1);
final int i = -e2 - q;
final int k = (i == 0 ? 1 : (int) ((i * 23219280L + 10000000L - 1) / 10000000L)) - 121;
final int j = q - k;
int actualShift = j - 3 * 31 - 21;
if (actualShift < 0) {
throw new IllegalArgumentException("" + actualShift);
}
int[] ints = POW5_SPLIT[i];
{
long mHigh = mv >>> 31;
long mLow = mv & 0x7fffffff;
long bits13 = mHigh * ints[0]; // 124
long bits03 = mLow * ints[0]; // 93
long bits12 = mHigh * ints[1]; // 93
long bits02 = mLow * ints[1]; // 62
long bits11 = mHigh * ints[2]; // 62
long bits01 = mLow * ints[2]; // 31
long bits10 = mHigh * ints[3]; // 31
long bits00 = mLow * ints[3]; // 0
dv = ((((((
((bits00 >>> 31) + bits01 + bits10) >>> 31)
+ bits02 + bits11) >>> 31)
+ bits03 + bits12) >>> 21)
+ (bits13 << 10)) >>> actualShift;
}
{
long mHigh = mp >>> 31;
long mLow = mp & 0x7fffffff;
long bits13 = mHigh * ints[0]; // 124
long bits03 = mLow * ints[0]; // 93
long bits12 = mHigh * ints[1]; // 93
long bits02 = mLow * ints[1]; // 62
long bits11 = mHigh * ints[2]; // 62
long bits01 = mLow * ints[2]; // 31
long bits10 = mHigh * ints[3]; // 31
long bits00 = mLow * ints[3]; // 0
dp = ((((((
((bits00 >>> 31) + bits01 + bits10) >>> 31)
+ bits02 + bits11) >>> 31)
+ bits03 + bits12) >>> 21)
+ (bits13 << 10)) >>> actualShift;
}
{
long mHigh = mm >>> 31;
long mLow = mm & 0x7fffffff;
long bits13 = mHigh * ints[0]; // 124
long bits03 = mLow * ints[0]; // 93
long bits12 = mHigh * ints[1]; // 93
long bits02 = mLow * ints[1]; // 62
long bits11 = mHigh * ints[2]; // 62
long bits01 = mLow * ints[2]; // 31
long bits10 = mHigh * ints[3]; // 31
long bits00 = mLow * ints[3]; // 0
dm = ((((((
((bits00 >>> 31) + bits01 + bits10) >>> 31)
+ bits02 + bits11) >>> 31)
+ bits03 + bits12) >>> 21)
+ (bits13 << 10)) >>> actualShift;
}
e10 = q + e2;
if (q <= 1) {
dvIsTrailingZeros = true;
if (even) {
dmIsTrailingZeros = mmShift == 1;
} else {
dp--;
}
} else if (q < 63) {
dvIsTrailingZeros = (mv & ((1L << (q - 1)) - 1)) == 0;
}
}
// Step 4: Find the shortest decimal representation in the interval of legal representations.
//
// We do some extra work here in order to follow Float/Double.toString semantics. In particular,
// that requires printing in scientific format if and only if the exponent is between -3 and 7,
// and it requires printing at least two decimal digits.
//
// Above, we moved the decimal dot all the way to the right, so now we need to count digits to
// figure out the correct exponent for scientific notation.
final int vplength; // = decimalLength(dp);
if (dp >= 1000000000000000000L) {
vplength = 19;
} else if (dp >= 100000000000000000L) {
vplength = 18;
} else if (dp >= 10000000000000000L) {
vplength = 17;
} else if (dp >= 1000000000000000L) {
vplength = 16;
} else if (dp >= 100000000000000L) {
vplength = 15;
} else if (dp >= 10000000000000L) {
vplength = 14;
} else if (dp >= 1000000000000L) {
vplength = 13;
} else if (dp >= 100000000000L) {
vplength = 12;
} else if (dp >= 10000000000L) {
vplength = 11;
} else if (dp >= 1000000000L) {
vplength = 10;
} else if (dp >= 100000000L) {
vplength = 9;
} else if (dp >= 10000000L) {
vplength = 8;
} else if (dp >= 1000000L) {
vplength = 7;
} else if (dp >= 100000L) {
vplength = 6;
} else if (dp >= 10000L) {
vplength = 5;
} else if (dp >= 1000L) {
vplength = 4;
} else if (dp >= 100L) {
vplength = 3;
} else if (dp >= 10L) {
vplength = 2;
} else {
vplength = 1;
}
int exp = e10 + vplength - 1;
// Double.toString semantics requires using scientific notation if and only if outside this range.
boolean scientificNotation = !((exp >= -3) && (exp < 7));
int removed = 0;
int lastRemovedDigit = 0;
long output;
if (dmIsTrailingZeros || dvIsTrailingZeros) {
while (dp / 10 > dm / 10) {
if ((dp < 100) && scientificNotation) {
// Double.toString semantics requires printing at least two digits.
break;
}
dmIsTrailingZeros &= dm % 10 == 0;
dvIsTrailingZeros &= lastRemovedDigit == 0;
lastRemovedDigit = (int) (dv % 10);
dp /= 10;
dv /= 10;
dm /= 10;
removed++;
}
if (dmIsTrailingZeros && even) {
while (dm % 10 == 0) {
if ((dp < 100) && scientificNotation) {
// Double.toString semantics requires printing at least two digits.
break;
}
dvIsTrailingZeros &= lastRemovedDigit == 0;
lastRemovedDigit = (int) (dv % 10);
dp /= 10;
dv /= 10;
dm /= 10;
removed++;
}
}
if (dvIsTrailingZeros && (lastRemovedDigit == 5) && (dv % 2 == 0)) {
// Round even if the exact numbers is .....50..0.
lastRemovedDigit = 4;
}
output = dv +
((dv == dm && !(dmIsTrailingZeros && even)) || (lastRemovedDigit >= 5) ? 1 : 0);
} else {
while (dp / 10 > dm / 10) {
if ((dp < 100) && scientificNotation) {
// Double.toString semantics requires printing at least two digits.
break;
}
lastRemovedDigit = (int) (dv % 10);
dp /= 10;
dv /= 10;
dm /= 10;
removed++;
}
output = dv + ((dv == dm || (lastRemovedDigit >= 5)) ? 1 : 0);
}
int olength = vplength - removed;
// Step 5: Print the decimal representation.
// We follow Double.toString semantics here.
if (sign) {
result[index++] = '-';
}
// Values in the interval [1E-3, 1E7) are special.
if (scientificNotation) {
// Print in the format x.xxxxxE-yy.
for (int i = 0; i < olength - 1; i++) {
int c = (int) (output % 10);
output /= 10;
result[index + olength - i] = (char) ('0' + c);
}
result[index] = (char) ('0' + output % 10);
result[index + 1] = '.';
index += olength + 1;
if (olength == 1) {
result[index++] = '0';
}
// Print 'E', the exponent sign, and the exponent, which has at most three digits.
result[index++] = 'E';
if (exp < 0) {
result[index++] = '-';
exp = -exp;
}
if (exp >= 100) {
result[index++] = (char) ('0' + exp / 100);
exp %= 100;
result[index++] = (char) ('0' + exp / 10);
} else if (exp >= 10) {
result[index++] = (char) ('0' + exp / 10);
}
result[index++] = (char) ('0' + exp % 10);
return index - off;
} else {
// Otherwise follow the Java spec for values in the interval [1E-3, 1E7).
if (exp < 0) {
// Decimal dot is before any of the digits.
result[index++] = '0';
result[index++] = '.';
for (int i = -1; i > exp; i--) {
result[index++] = '0';
}
int current = index;
for (int i = 0; i < olength; i++) {
result[current + olength - i - 1] = (char) ('0' + output % 10);
output /= 10;
index++;
}
} else if (exp + 1 >= olength) {
// Decimal dot is after any of the digits.
for (int i = 0; i < olength; i++) {
result[index + olength - i - 1] = (char) ('0' + output % 10);
output /= 10;
}
index += olength;
for (int i = olength; i < exp + 1; i++) {
result[index++] = '0';
}
result[index++] = '.';
result[index++] = '0';
} else {
// Decimal dot is somewhere between the digits.
int current = index + 1;
for (int i = 0; i < olength; i++) {
if (olength - i - 1 == exp) {
result[current + olength - i - 1] = '.';
current--;
}
result[current + olength - i - 1] = (char) ('0' + output % 10);
output /= 10;
}
index += olength + 1;
}
return index - off;
}
}
}