Author: centic
Date: Mon Jul 15 05:41:14 2024
New Revision: 1919239
URL: http://svn.apache.org/viewvc?rev=1919239&view=rev
Log:
Optimize generating numbers for bullets in Word
Using char[] instead of String improves performance of this
operation considerably, especially in JDK 11+ where StringBuilder
was switched to work on bytes instead of chars.
This is likely only relevant for very large documents, it was visible
in a synthetic test-file from fuzzing.
Modified:
poi/trunk/poi-scratchpad/src/main/java/org/apache/poi/hwpf/converter/NumberFormatter.java
Modified:
poi/trunk/poi-scratchpad/src/main/java/org/apache/poi/hwpf/converter/NumberFormatter.java
URL:
http://svn.apache.org/viewvc/poi/trunk/poi-scratchpad/src/main/java/org/apache/poi/hwpf/converter/NumberFormatter.java?rev=1919239&r1=1919238&r2=1919239&view=diff
==============================================================================
---
poi/trunk/poi-scratchpad/src/main/java/org/apache/poi/hwpf/converter/NumberFormatter.java
(original)
+++
poi/trunk/poi-scratchpad/src/main/java/org/apache/poi/hwpf/converter/NumberFormatter.java
Mon Jul 15 05:41:14 2024
@@ -19,6 +19,7 @@
package org.apache.poi.hwpf.converter;
+import java.util.Arrays;
import java.util.Locale;
import org.apache.poi.util.Beta;
@@ -28,8 +29,12 @@ import org.apache.poi.util.Beta;
*/
@Beta
public final class NumberFormatter {
- private static final String[] ROMAN_LETTERS = { "m", "cm", "d", "cd", "c",
- "xc", "l", "xl", "x", "ix", "v", "iv", "i" };
+ // use char[] instead of String to speed up StringBuilder.append(),
especially in JDK 11+
+ // where StringBuilder internally switched from char[] to byte[]
+ private static final char[][] ROMAN_LETTERS = Arrays.stream(
+ new String[] { "m", "cm", "d", "cd", "c", "xc", "l", "xl", "x",
"ix", "v", "iv", "i" }).
+ map(String::toCharArray).
+ toArray(char[][]::new);
private static final int[] ROMAN_VALUES = { 1000, 900, 500, 400, 100, 90,
50, 40, 10, 9, 5, 4, 1 };
@@ -86,7 +91,7 @@ public final class NumberFormatter {
StringBuilder result = new StringBuilder();
for ( int i = 0; i < ROMAN_LETTERS.length; i++ ) {
- String letter = ROMAN_LETTERS[i];
+ char[] letter = ROMAN_LETTERS[i];
int value = ROMAN_VALUES[i];
while ( number >= value ) {
number -= value;
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