com.alibaba.fastjson2.util

Class NumberUtils

java.lang.Object

com.alibaba.fastjson2.util.NumberUtils

public final class NumberUtils
extends java.lang.Object

Author: wangy

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static interface	NumberUtils.LongBiFunction

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static long	INFI
(package private) static long	INFINITY
(package private) static int	MOD_DOUBLE_EXP
(package private) static long	MOD_DOUBLE_MANTISSA
(package private) static int	MOD_FLOAT_EXP
(package private) static int	MOD_FLOAT_MANTISSA
(package private) static NumberUtils.LongBiFunction	MULTIPLY_HIGH
(package private) static double[]	NEGATIVE_DECIMAL_POWER
(package private) static char[][]	NEGATIVE_DECIMAL_POWER_CHARS
(package private) static long	NITY
(package private) static double[]	POSITIVE_DECIMAL_POWER
(package private) static char[][]	POSITIVE_DECIMAL_POWER_CHARS
(package private) static long[]	POW10_LONG_VALUES
(package private) static java.math.BigInteger[]	POW5_BI_VALUES
(package private) static long[]	POW5_LONG_VALUES
(package private) static short[]	TWO_DIGITS_16_BITS
(package private) static int[]	TWO_DIGITS_32_BITS

Constructor Summary

Constructors

Modifier	Constructor and Description
private	NumberUtils()

Method Summary

Modifier and Type	Method and Description
static Scientific	doubleToScientific(double doubleValue) Conversion of ieee floating point numbers to Scientific notation
static Scientific	floatToScientific(float floatValue)
(package private) static long	multiplyHigh(long x, long y)
(package private) static long	multiplyHighAndShift(long x, long y, int shift) multiplyOutput
(package private) static long	multiplyHighAndShift(long x, long y, long y32, int s) Unsigned algorithm: (H * 2^64 * 2^n + L * 2^n + H1 * 2^64 + L1) / 2^(n+s) = (H * 2^64 + L + (H1 * 2^64 + L1) / 2^n) / 2^s
private static int	writeDecimal(long value, int digitCnt, int e10, byte[] buf, int off)
private static int	writeDecimal(long value, int digitCnt, int e10, char[] buf, int off)
static int	writeDouble(byte[] buf, int off, double doubleValue, boolean json, boolean writeSpecialAsString)
static int	writeDouble(char[] buf, int off, double doubleValue, boolean json, boolean writeSpecialAsString)
static int	writeFloat(byte[] buf, int off, float floatValue, boolean json, boolean writeSpecialAsString)
static int	writeFloat(char[] buf, int off, float floatValue, boolean json, boolean writeSpecialAsString)
private static int	writeSpecial(byte[] buf, int off, float floatValue, boolean json, boolean writeSpecialAsString)
private static int	writeSpecial(char[] buf, int off, float floatValue, boolean json, boolean writeSpecialAsString)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MULTIPLY_HIGH

static final NumberUtils.LongBiFunction MULTIPLY_HIGH

INFI

static final long INFI

NITY

static final long NITY

INFINITY

static final long INFINITY

POSITIVE_DECIMAL_POWER

static final double[] POSITIVE_DECIMAL_POWER

NEGATIVE_DECIMAL_POWER

static final double[] NEGATIVE_DECIMAL_POWER

POW10_LONG_VALUES

static final long[] POW10_LONG_VALUES

POW5_LONG_VALUES

static final long[] POW5_LONG_VALUES

POW5_BI_VALUES

static final java.math.BigInteger[] POW5_BI_VALUES

MOD_DOUBLE_EXP

static final int MOD_DOUBLE_EXP

See Also:

Constant Field Values

MOD_DOUBLE_MANTISSA

static final long MOD_DOUBLE_MANTISSA

See Also:

Constant Field Values

POSITIVE_DECIMAL_POWER_CHARS

static final char[][] POSITIVE_DECIMAL_POWER_CHARS

NEGATIVE_DECIMAL_POWER_CHARS

static final char[][] NEGATIVE_DECIMAL_POWER_CHARS

MOD_FLOAT_EXP

static final int MOD_FLOAT_EXP

See Also:

Constant Field Values

MOD_FLOAT_MANTISSA

static final int MOD_FLOAT_MANTISSA

See Also:

Constant Field Values

TWO_DIGITS_32_BITS

static final int[] TWO_DIGITS_32_BITS

TWO_DIGITS_16_BITS

static final short[] TWO_DIGITS_16_BITS

Constructor Detail

NumberUtils

private NumberUtils()

Method Detail

multiplyHigh

static long multiplyHigh(long x,
                         long y)

multiplyHighAndShift

static long multiplyHighAndShift(long x,
                                 long y,
                                 int shift)

multiplyOutput

Parameters:

x - > 0

y - > 0

shift - > 0

Returns:

multiplyHighAndShift

static long multiplyHighAndShift(long x,
                                 long y,
                                 long y32,
                                 int s)

Unsigned algorithm: (H * 2^64 * 2^n + L * 2^n + H1 * 2^64 + L1) / 2^(n+s) = (H * 2^64 + L + (H1 * 2^64 + L1) / 2^n) / 2^s

use BigInteger: BigInteger.valueOf(pd.y).shiftLeft(n).add(BigInteger.valueOf(f & MASK_32_BITS)).multiply(BigInteger.valueOf(x)).shiftRight(s + n).longValue()

Parameters:

x - 63bits

y - 63bits

y32 - unsigned int32 f(32bits)

s - s > 0

Returns:

doubleToScientific

public static Scientific doubleToScientific(double doubleValue)

Conversion of ieee floating point numbers to Scientific notation

Using the difference estimation method

The output may not be the shortest, but the general result is correct

Parameters:

doubleValue - > 0

writeDouble

public static int writeDouble(byte[] buf,
                              int off,
                              double doubleValue,
                              boolean json,
                              boolean writeSpecialAsString)

writeDouble

public static int writeDouble(char[] buf,
                              int off,
                              double doubleValue,
                              boolean json,
                              boolean writeSpecialAsString)

writeFloat

public static int writeFloat(byte[] buf,
                             int off,
                             float floatValue,
                             boolean json,
                             boolean writeSpecialAsString)

writeFloat

public static int writeFloat(char[] buf,
                             int off,
                             float floatValue,
                             boolean json,
                             boolean writeSpecialAsString)

writeSpecial

private static int writeSpecial(byte[] buf,
                                int off,
                                float floatValue,
                                boolean json,
                                boolean writeSpecialAsString)

writeSpecial

private static int writeSpecial(char[] buf,
                                int off,
                                float floatValue,
                                boolean json,
                                boolean writeSpecialAsString)

floatToScientific

public static Scientific floatToScientific(float floatValue)

writeDecimal

private static int writeDecimal(long value,
                                int digitCnt,
                                int e10,
                                byte[] buf,
                                int off)

writeDecimal

private static int writeDecimal(long value,
                                int digitCnt,
                                int e10,
                                char[] buf,
                                int off)