On Sat, 15 Jun 2024 01:59:42 GMT, Shaojin Wen <d...@openjdk.org> wrote:
> The current versions of FloatToDecimal and DoubleToDecimal allocate
> additional objects. Reducing these allocations can improve the performance of
> Float/Double.toString and AbstractStringBuilder's append(float/double).
>
> This patch is just a code refactoring to reduce object allocation, but does
> not change the Float/Double to decimal algorithm.
>
> The following code comments the allocated objects to be removed.
>
>
> class FloatToDecimal {
> public static String toString(float v) {
> // allocate object FloatToDecimal
> return new FloatToDecimal().toDecimalString(v);
> }
>
> public static Appendable appendTo(float v, Appendable app)
> throws IOException {
> // allocate object FloatToDecimal
> return new FloatToDecimal().appendDecimalTo(v, app);
> }
>
> private Appendable appendDecimalTo(float v, Appendable app)
> throws IOException {
> switch (toDecimal(v)) {
> case NON_SPECIAL:
> // allocate object char[]
> char[] chars = new char[index + 1];
> for (int i = 0; i < chars.length; ++i) {
> chars[i] = (char) bytes[i];
> }
> if (app instanceof StringBuilder builder) {
> return builder.append(chars);
> }
> if (app instanceof StringBuffer buffer) {
> return buffer.append(chars);
> }
> for (char c : chars) {
> app.append(c);
> }
> return app;
> // ...
> }
> }
> }
>
> class DoubleToDecimal {
> public static String toString(double v) {
> // allocate object DoubleToDecimal
> return new DoubleToDecimal(false).toDecimalString(v);
> }
>
> public static Appendable appendTo(double v, Appendable app)
> throws IOException {
> // allocate object DoubleToDecimal
> return new DoubleToDecimal(false).appendDecimalTo(v, app);
> }
>
> private Appendable appendDecimalTo(double v, Appendable app)
> throws IOException {
> switch (toDecimal(v, null)) {
> case NON_SPECIAL:
> // allocate object char[]
> char[] chars = new char[index + 1];
> for (int i = 0; i < chars.length; ++i) {
> chars[i] = (char) bytes[i];
> }
> if (app instanceof StringBuilder builder) {
> return builder.append(chars);
> }
> ...
This pull request has now been integrated.
Changeset: 9d20b58f
Author: Shaojin Wen <shaojin.we...@alibaba-inc.com>
Committer: Chen Liang <li...@openjdk.org>
URL:
https://git.openjdk.org/jdk/commit/9d20b58f40275002afa0348d94d5592a26894e88
Stats: 613 lines in 5 files changed: 264 ins; 212 del; 137 mod
8334328: Reduce object allocation for FloatToDecimal and DoubleToDecimal
Reviewed-by: redestad, rgiulietti
-------------
PR: https://git.openjdk.org/jdk/pull/19730
