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8276220: Reduce excessive allocations in DateTimeFormatter
Reviewed-by: scolebourne, naoto
1 parent 0ab910d commit ce8c767

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4 files changed

+552
-31
lines changed

4 files changed

+552
-31
lines changed

‎src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java

+259-22
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
* Copyright (c) 2012, 2020, Oracle and/or its affiliates. All rights reserved.
2+
* Copyright (c) 2012, 2021, Oracle and/or its affiliates. All rights reserved.
33
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
44
*
55
* This code is free software; you can redistribute it and/or modify it
@@ -701,11 +701,20 @@ private DateTimeFormatterBuilder appendValue(NumberPrinterParser pp) {
701701
*/
702702
public DateTimeFormatterBuilder appendFraction(
703703
TemporalField field, int minWidth, int maxWidth, boolean decimalPoint) {
704-
if (minWidth == maxWidth && decimalPoint == false) {
705-
// adjacent parsing
706-
appendValue(new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint));
704+
if (field == NANO_OF_SECOND) {
705+
if (minWidth == maxWidth && decimalPoint == false) {
706+
// adjacent parsing
707+
appendValue(new NanosPrinterParser(minWidth, maxWidth, decimalPoint));
708+
} else {
709+
appendInternal(new NanosPrinterParser(minWidth, maxWidth, decimalPoint));
710+
}
707711
} else {
708-
appendInternal(new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint));
712+
if (minWidth == maxWidth && decimalPoint == false) {
713+
// adjacent parsing
714+
appendValue(new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint));
715+
} else {
716+
appendInternal(new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint));
717+
}
709718
}
710719
return this;
711720
}
@@ -2758,6 +2767,24 @@ NumberPrinterParser withSubsequentWidth(int subsequentWidth) {
27582767
return new NumberPrinterParser(field, minWidth, maxWidth, signStyle, this.subsequentWidth + subsequentWidth);
27592768
}
27602769

2770+
/*
2771+
* Copied from Long.stringSize
2772+
*/
2773+
private static int stringSize(long x) {
2774+
int d = 1;
2775+
if (x >= 0) {
2776+
d = 0;
2777+
x = -x;
2778+
}
2779+
long p = -10;
2780+
for (int i = 1; i < 19; i++) {
2781+
if (x > p)
2782+
return i + d;
2783+
p = 10 * p;
2784+
}
2785+
return 19 + d;
2786+
}
2787+
27612788
@Override
27622789
public boolean format(DateTimePrintContext context, StringBuilder buf) {
27632790
Long valueLong = context.getValue(field);
@@ -2766,18 +2793,21 @@ public boolean format(DateTimePrintContext context, StringBuilder buf) {
27662793
}
27672794
long value = getValue(context, valueLong);
27682795
DecimalStyle decimalStyle = context.getDecimalStyle();
2769-
String str = (value == Long.MIN_VALUE ? "9223372036854775808" : Long.toString(Math.abs(value)));
2770-
if (str.length() > maxWidth) {
2796+
int size = stringSize(value);
2797+
if (value < 0) {
2798+
size--;
2799+
}
2800+
2801+
if (size > maxWidth) {
27712802
throw new DateTimeException("Field " + field +
27722803
" cannot be printed as the value " + value +
27732804
" exceeds the maximum print width of " + maxWidth);
27742805
}
2775-
str = decimalStyle.convertNumberToI18N(str);
27762806

27772807
if (value >= 0) {
27782808
switch (signStyle) {
27792809
case EXCEEDS_PAD:
2780-
if (minWidth < 19 && value >= EXCEED_POINTS[minWidth]) {
2810+
if (minWidth < 19 && size > minWidth) {
27812811
buf.append(decimalStyle.getPositiveSign());
27822812
}
27832813
break;
@@ -2793,10 +2823,16 @@ public boolean format(DateTimePrintContext context, StringBuilder buf) {
27932823
" cannot be negative according to the SignStyle");
27942824
}
27952825
}
2796-
for (int i = 0; i < minWidth - str.length(); i++) {
2797-
buf.append(decimalStyle.getZeroDigit());
2826+
char zeroDigit = decimalStyle.getZeroDigit();
2827+
for (int i = 0; i < minWidth - size; i++) {
2828+
buf.append(zeroDigit);
2829+
}
2830+
if (zeroDigit == '0' && value != Long.MIN_VALUE) {
2831+
buf.append(Math.abs(value));
2832+
} else {
2833+
String str = value == Long.MIN_VALUE ? "9223372036854775808" : Long.toString(Math.abs(value));
2834+
buf.append(decimalStyle.convertNumberToI18N(str));
27982835
}
2799-
buf.append(str);
28002836
return true;
28012837
}
28022838

@@ -3111,12 +3147,216 @@ public String toString() {
31113147
}
31123148
}
31133149

3150+
//-----------------------------------------------------------------------
3151+
/**
3152+
* Prints and parses a NANO_OF_SECOND field with optional padding.
3153+
*/
3154+
static final class NanosPrinterParser extends NumberPrinterParser {
3155+
private final boolean decimalPoint;
3156+
3157+
/**
3158+
* Constructor.
3159+
*
3160+
* @param minWidth the minimum width to output, from 0 to 9
3161+
* @param maxWidth the maximum width to output, from 0 to 9
3162+
* @param decimalPoint whether to output the localized decimal point symbol
3163+
*/
3164+
NanosPrinterParser(int minWidth, int maxWidth, boolean decimalPoint) {
3165+
this(minWidth, maxWidth, decimalPoint, 0);
3166+
if (minWidth < 0 || minWidth > 9) {
3167+
throw new IllegalArgumentException("Minimum width must be from 0 to 9 inclusive but was " + minWidth);
3168+
}
3169+
if (maxWidth < 1 || maxWidth > 9) {
3170+
throw new IllegalArgumentException("Maximum width must be from 1 to 9 inclusive but was " + maxWidth);
3171+
}
3172+
if (maxWidth < minWidth) {
3173+
throw new IllegalArgumentException("Maximum width must exceed or equal the minimum width but " +
3174+
maxWidth + " < " + minWidth);
3175+
}
3176+
}
3177+
3178+
/**
3179+
* Constructor.
3180+
*
3181+
* @param minWidth the minimum width to output, from 0 to 9
3182+
* @param maxWidth the maximum width to output, from 0 to 9
3183+
* @param decimalPoint whether to output the localized decimal point symbol
3184+
* @param subsequentWidth the subsequentWidth for this instance
3185+
*/
3186+
NanosPrinterParser(int minWidth, int maxWidth, boolean decimalPoint, int subsequentWidth) {
3187+
super(NANO_OF_SECOND, minWidth, maxWidth, SignStyle.NOT_NEGATIVE, subsequentWidth);
3188+
this.decimalPoint = decimalPoint;
3189+
}
3190+
3191+
/**
3192+
* Returns a new instance with fixed width flag set.
3193+
*
3194+
* @return a new updated printer-parser, not null
3195+
*/
3196+
@Override
3197+
NanosPrinterParser withFixedWidth() {
3198+
if (subsequentWidth == -1) {
3199+
return this;
3200+
}
3201+
return new NanosPrinterParser(minWidth, maxWidth, decimalPoint, -1);
3202+
}
3203+
3204+
/**
3205+
* Returns a new instance with an updated subsequent width.
3206+
*
3207+
* @param subsequentWidth the width of subsequent non-negative numbers, 0 or greater
3208+
* @return a new updated printer-parser, not null
3209+
*/
3210+
@Override
3211+
NanosPrinterParser withSubsequentWidth(int subsequentWidth) {
3212+
return new NanosPrinterParser(minWidth, maxWidth, decimalPoint, this.subsequentWidth + subsequentWidth);
3213+
}
3214+
3215+
/**
3216+
* For NanosPrinterParser, the width is fixed if context is strict,
3217+
* minWidth equal to maxWidth and decimalpoint is absent.
3218+
* @param context the context
3219+
* @return if the field is fixed width
3220+
* @see #appendFraction(java.time.temporal.TemporalField, int, int, boolean)
3221+
*/
3222+
@Override
3223+
boolean isFixedWidth(DateTimeParseContext context) {
3224+
if (context.isStrict() && minWidth == maxWidth && decimalPoint == false) {
3225+
return true;
3226+
}
3227+
return false;
3228+
}
3229+
3230+
// Simplified variant of Integer.stringSize that assumes positive values
3231+
private static int stringSize(int x) {
3232+
int p = 10;
3233+
for (int i = 1; i < 10; i++) {
3234+
if (x < p)
3235+
return i;
3236+
p = 10 * p;
3237+
}
3238+
return 10;
3239+
}
3240+
3241+
private static final int[] TENS = new int[] {
3242+
1,
3243+
10,
3244+
100,
3245+
1000,
3246+
10000,
3247+
100000,
3248+
1000000,
3249+
10000000,
3250+
100000000
3251+
};
3252+
3253+
@Override
3254+
public boolean format(DateTimePrintContext context, StringBuilder buf) {
3255+
Long value = context.getValue(field);
3256+
if (value == null) {
3257+
return false;
3258+
}
3259+
int val = field.range().checkValidIntValue(value, field);
3260+
DecimalStyle decimalStyle = context.getDecimalStyle();
3261+
int stringSize = stringSize(val);
3262+
char zero = decimalStyle.getZeroDigit();
3263+
if (val == 0 || stringSize < 10 - maxWidth) {
3264+
// 0 or would round down to 0
3265+
// to get output identical to FractionPrinterParser use minWidth if the
3266+
// value is zero, maxWidth otherwise
3267+
int width = val == 0 ? minWidth : maxWidth;
3268+
if (width > 0) {
3269+
if (decimalPoint) {
3270+
buf.append(decimalStyle.getDecimalSeparator());
3271+
}
3272+
for (int i = 0; i < width; i++) {
3273+
buf.append(zero);
3274+
}
3275+
}
3276+
} else {
3277+
if (decimalPoint) {
3278+
buf.append(decimalStyle.getDecimalSeparator());
3279+
}
3280+
// add leading zeros
3281+
for (int i = 9 - stringSize; i > 0; i--) {
3282+
buf.append(zero);
3283+
}
3284+
// truncate unwanted digits
3285+
if (maxWidth < 9) {
3286+
val /= TENS[9 - maxWidth];
3287+
}
3288+
// truncate zeros
3289+
for (int i = maxWidth; i > minWidth; i--) {
3290+
if ((val % 10) != 0) {
3291+
break;
3292+
}
3293+
val /= 10;
3294+
}
3295+
if (zero == '0') {
3296+
buf.append(val);
3297+
} else {
3298+
buf.append(decimalStyle.convertNumberToI18N(Integer.toString(val)));
3299+
}
3300+
}
3301+
return true;
3302+
}
3303+
3304+
@Override
3305+
public int parse(DateTimeParseContext context, CharSequence text, int position) {
3306+
int effectiveMin = (context.isStrict() || isFixedWidth(context) ? minWidth : 0);
3307+
int effectiveMax = (context.isStrict() || isFixedWidth(context) ? maxWidth : 9);
3308+
int length = text.length();
3309+
if (position == length) {
3310+
// valid if whole field is optional, invalid if minimum width
3311+
return (effectiveMin > 0 ? ~position : position);
3312+
}
3313+
if (decimalPoint) {
3314+
if (text.charAt(position) != context.getDecimalStyle().getDecimalSeparator()) {
3315+
// valid if whole field is optional, invalid if minimum width
3316+
return (effectiveMin > 0 ? ~position : position);
3317+
}
3318+
position++;
3319+
}
3320+
int minEndPos = position + effectiveMin;
3321+
if (minEndPos > length) {
3322+
return ~position; // need at least min width digits
3323+
}
3324+
int maxEndPos = Math.min(position + effectiveMax, length);
3325+
int total = 0; // can use int because we are only parsing up to 9 digits
3326+
int pos = position;
3327+
while (pos < maxEndPos) {
3328+
char ch = text.charAt(pos);
3329+
int digit = context.getDecimalStyle().convertToDigit(ch);
3330+
if (digit < 0) {
3331+
if (pos < minEndPos) {
3332+
return ~position; // need at least min width digits
3333+
}
3334+
break;
3335+
}
3336+
pos++;
3337+
total = total * 10 + digit;
3338+
}
3339+
for (int i = 9 - (pos - position); i > 0; i--) {
3340+
total *= 10;
3341+
}
3342+
return context.setParsedField(field, total, position, pos);
3343+
}
3344+
3345+
@Override
3346+
public String toString() {
3347+
String decimal = (decimalPoint ? ",DecimalPoint" : "");
3348+
return "Fraction(" + field + "," + minWidth + "," + maxWidth + decimal + ")";
3349+
}
3350+
}
3351+
31143352
//-----------------------------------------------------------------------
31153353
/**
31163354
* Prints and parses a numeric date-time field with optional padding.
31173355
*/
31183356
static final class FractionPrinterParser extends NumberPrinterParser {
31193357
private final boolean decimalPoint;
3358+
private final BigDecimal minBD;
3359+
private final BigDecimal rangeBD;
31203360

31213361
/**
31223362
* Constructor.
@@ -3156,6 +3396,9 @@ static final class FractionPrinterParser extends NumberPrinterParser {
31563396
FractionPrinterParser(TemporalField field, int minWidth, int maxWidth, boolean decimalPoint, int subsequentWidth) {
31573397
super(field, minWidth, maxWidth, SignStyle.NOT_NEGATIVE, subsequentWidth);
31583398
this.decimalPoint = decimalPoint;
3399+
ValueRange range = field.range();
3400+
this.minBD = BigDecimal.valueOf(range.getMinimum());
3401+
this.rangeBD = BigDecimal.valueOf(range.getMaximum()).subtract(minBD).add(BigDecimal.ONE);
31593402
}
31603403

31613404
/**
@@ -3217,12 +3460,12 @@ public boolean format(DateTimePrintContext context, StringBuilder buf) {
32173460
} else {
32183461
int outputScale = Math.min(Math.max(fraction.scale(), minWidth), maxWidth);
32193462
fraction = fraction.setScale(outputScale, RoundingMode.FLOOR);
3220-
String str = fraction.toPlainString().substring(2);
3221-
str = decimalStyle.convertNumberToI18N(str);
32223463
if (decimalPoint) {
32233464
buf.append(decimalStyle.getDecimalSeparator());
32243465
}
3225-
buf.append(str);
3466+
String str = fraction.toPlainString();
3467+
str = decimalStyle.convertNumberToI18N(str);
3468+
buf.append(str, 2, str.length());
32263469
}
32273470
return true;
32283471
}
@@ -3284,10 +3527,7 @@ public int parse(DateTimeParseContext context, CharSequence text, int position)
32843527
* @throws DateTimeException if the value cannot be converted to a fraction
32853528
*/
32863529
private BigDecimal convertToFraction(long value) {
3287-
ValueRange range = field.range();
3288-
range.checkValidValue(value, field);
3289-
BigDecimal minBD = BigDecimal.valueOf(range.getMinimum());
3290-
BigDecimal rangeBD = BigDecimal.valueOf(range.getMaximum()).subtract(minBD).add(BigDecimal.ONE);
3530+
field.range().checkValidValue(value, field);
32913531
BigDecimal valueBD = BigDecimal.valueOf(value).subtract(minBD);
32923532
BigDecimal fraction = valueBD.divide(rangeBD, 9, RoundingMode.FLOOR);
32933533
// stripTrailingZeros bug
@@ -3311,9 +3551,6 @@ private BigDecimal convertToFraction(long value) {
33113551
* @throws DateTimeException if the value cannot be converted
33123552
*/
33133553
private long convertFromFraction(BigDecimal fraction) {
3314-
ValueRange range = field.range();
3315-
BigDecimal minBD = BigDecimal.valueOf(range.getMinimum());
3316-
BigDecimal rangeBD = BigDecimal.valueOf(range.getMaximum()).subtract(minBD).add(BigDecimal.ONE);
33173554
BigDecimal valueBD = fraction.multiply(rangeBD).setScale(0, RoundingMode.FLOOR).add(minBD);
33183555
return valueBD.longValueExact();
33193556
}

‎src/java.base/share/classes/java/time/format/DateTimePrintContext.java

+3-3
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
* Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
2+
* Copyright (c) 2012, 2021, Oracle and/or its affiliates. All rights reserved.
33
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
44
*
55
* This code is free software; you can redistribute it and/or modify it
@@ -98,11 +98,11 @@ final class DateTimePrintContext {
9898
/**
9999
* The temporal being output.
100100
*/
101-
private TemporalAccessor temporal;
101+
private final TemporalAccessor temporal;
102102
/**
103103
* The formatter, not null.
104104
*/
105-
private DateTimeFormatter formatter;
105+
private final DateTimeFormatter formatter;
106106
/**
107107
* Whether the current formatter is optional.
108108
*/

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