elena 2003/07/28 16:27:36
Modified: java/src/org/apache/xerces/util XMLStringBuffer.java
Log:
Performance patch by Thomas DeWeese from Apache Batik:
the patch makes XMLStringBuffer use array doubling instead of a fixed 32 char
increment.
For one of Batik test files with a 500Kb embedded image, this patch reduces
parse time from ~4.5min to .8 sec (n*log(n) is much better than n^2).
This is not even a particularly extreme case for SVG.
Revision Changes Path
1.5 +15 -13 xml-xerces/java/src/org/apache/xerces/util/XMLStringBuffer.java
Index: XMLStringBuffer.java
===================================================================
RCS file: /home/cvs/xml-xerces/java/src/org/apache/xerces/util/XMLStringBuffer.java,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- XMLStringBuffer.java 29 Jan 2002 01:15:18 -0000 1.4
+++ XMLStringBuffer.java 28 Jul 2003 23:27:36 -0000 1.5
@@ -91,15 +91,6 @@
public static final int DEFAULT_SIZE = 32;
//
- // Data
- //
-
- // private
-
- /** One char buffer. */
- private char[] fOneCharBuffer = new char[1];
-
- //
// Constructors
//
@@ -159,8 +150,16 @@
* @param c
*/
public void append(char c) {
- fOneCharBuffer[0] = c;
- append(fOneCharBuffer, 0, 1);
+ if (this.length + 1 > this.ch.length) {
+ int newLength = this.ch.length*2;
+ if (newLength < this.ch.length + DEFAULT_SIZE)
+ newLength = this.ch.length + DEFAULT_SIZE;
+ char[] newch = new char[newLength];
+ System.arraycopy(this.ch, 0, newch, 0, this.length);
+ this.ch = newch;
+ }
+ this.ch[this.length] = c;
+ this.length++;
} // append(char)
/**
@@ -171,7 +170,10 @@
public void append(String s) {
int length = s.length();
if (this.length + length > this.ch.length) {
- char[] newch = new char[this.ch.length + length + DEFAULT_SIZE];
+ int newLength = this.ch.length*2;
+ if (newLength < this.length + length + DEFAULT_SIZE)
+ newLength = this.ch.length + length + DEFAULT_SIZE;
+ char[] newch = new char[newLength];
System.arraycopy(this.ch, 0, newch, 0, this.length);
this.ch = newch;
}
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