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8310929: Optimization for Integer.toString

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Reviewed-by: redestad, rriggs
This commit is contained in:
shaojin.wensj 2023-09-08 02:13:52 +00:00 • committed by Yi Yang
parent 111ecdbaf5
commit 4b43c25fe3
8 changed files with 215 additions and 172 deletions
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53
src/java.base/share/classes/java/lang/StringUTF16.java
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@ -33,6 +33,7 @@ import java.util.function.IntConsumer;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import jdk.internal.util.ArraysSupport;
import jdk.internal.util.ByteArrayLittleEndian;
import jdk.internal.vm.annotation.DontInline;
import jdk.internal.vm.annotation.ForceInline;
import jdk.internal.vm.annotation.IntrinsicCandidate;
@ -1519,7 +1520,7 @@ final class StringUTF16 {
// been done by the caller.
/**
* This is a variant of {@link Integer#getChars(int, int, byte[])}, but for
* This is a variant of {@link StringLatin1#getChars(int, int, byte[])}, but for
* UTF-16 coder.
*
* @param i value to convert
@ -1528,6 +1529,7 @@ final class StringUTF16 {
* @return index of the most significant digit or minus sign, if present
*/
static int getChars(int i, int index, byte[] buf) {
// Used by trusted callers. Assumes all necessary bounds checks have been done by the caller.
int q, r;
int charPos = index;
@ -1541,14 +1543,23 @@ final class StringUTF16 {
q = i / 100;
r = (q * 100) - i;
i = q;
putChar(buf, --charPos, Integer.DigitOnes[r]);
putChar(buf, --charPos, Integer.DigitTens[r]);
int packed = (int) StringLatin1.PACKED_DIGITS[r];
int inflated = ((packed & 0xFF00) << 8) | (packed & 0xFF);
charPos -= 2;
ByteArrayLittleEndian.setInt(buf, charPos << 1, inflated);
}
// We know there are at most two digits left at this point.
putChar(buf, --charPos, Integer.DigitOnes[-i]);
if (i < -9) {
putChar(buf, --charPos, Integer.DigitTens[-i]);
int packed = (int) StringLatin1.PACKED_DIGITS[-i];
int inflated = ((packed & 0xFF00) << 8) | (packed & 0xFF);
charPos -= 2;
ByteArrayLittleEndian.setInt(buf, charPos << 1, inflated);
} else {
putChar(buf, --charPos, '0' - i);
}
if (negative) {
@ -1558,7 +1569,7 @@ final class StringUTF16 {
}
/**
* This is a variant of {@link Long#getChars(long, int, byte[])}, but for
* This is a variant of {@link StringLatin1#getChars(long, int, byte[])}, but for
* UTF-16 coder.
*
* @param i value to convert
@ -1567,8 +1578,8 @@ final class StringUTF16 {
* @return index of the most significant digit or minus sign, if present
*/
static int getChars(long i, int index, byte[] buf) {
// Used by trusted callers. Assumes all necessary bounds checks have been done by the caller.
long q;
int r;
int charPos = index;
boolean negative = (i < 0);
@ -1579,10 +1590,13 @@ final class StringUTF16 {
// Get 2 digits/iteration using longs until quotient fits into an int
while (i <= Integer.MIN_VALUE) {
q = i / 100;
r = (int)((q * 100) - i);
int packed = (int) StringLatin1.PACKED_DIGITS[(int)((q * 100) - i)];
int inflated = ((packed & 0xFF00) << 8) | (packed & 0xFF);
charPos -= 2;
ByteArrayLittleEndian.setInt(buf, charPos << 1, inflated);
i = q;
putChar(buf, --charPos, Integer.DigitOnes[r]);
putChar(buf, --charPos, Integer.DigitTens[r]);
}
// Get 2 digits/iteration using ints
@ -1590,16 +1604,25 @@ final class StringUTF16 {
int i2 = (int)i;
while (i2 <= -100) {
q2 = i2 / 100;
r = (q2 * 100) - i2;
int packed = (int) StringLatin1.PACKED_DIGITS[(q2 * 100) - i2];
int inflated = ((packed & 0xFF00) << 8) | (packed & 0xFF);
charPos -= 2;
ByteArrayLittleEndian.setInt(buf, charPos << 1, inflated);
i2 = q2;
putChar(buf, --charPos, Integer.DigitOnes[r]);
putChar(buf, --charPos, Integer.DigitTens[r]);
}
// We know there are at most two digits left at this point.
putChar(buf, --charPos, Integer.DigitOnes[-i2]);
if (i2 < -9) {
putChar(buf, --charPos, Integer.DigitTens[-i2]);
charPos -= 2;
int packed = (int) StringLatin1.PACKED_DIGITS[-i2];
int inflated = ((packed & 0xFF00) << 8) | (packed & 0xFF);
ByteArrayLittleEndian.setInt(buf, charPos << 1, inflated);
} else {
putChar(buf, --charPos, '0' - i2);
}
if (negative) {