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Minor code improvements, fixed comments 

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@723146 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Josh Micich 2008-12-03 23:39:11 +00:00
parent 3a9e4eb667
commit 2ebe3f7e32
1 changed files with 39 additions and 15 deletions
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54
src/java/org/apache/poi/ss/formula/Formula.java
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@ -1,3 +1,20 @@
/* ====================================================================
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==================================================================== */
package org.apache.poi.ss.formula;
import java.util.Arrays;
@ -14,9 +31,16 @@ import org.apache.poi.util.LittleEndianByteArrayInputStream;
import org.apache.poi.util.LittleEndianInput;
import org.apache.poi.util.LittleEndianOutput;
/**
* Encapsulates an encoded formula token array.
*
* @author Josh Micich
*/
public class Formula {
private static final byte[] EMPTY_BYTE_ARRAY = { };
private static final Formula EMPTY = new Formula(new byte[0], 0);
/** immutable */
private final byte[] _byteEncoding;
private final int _encodedTokenLen;
@ -24,17 +48,17 @@ public class Formula {
_byteEncoding = byteEncoding;
_encodedTokenLen = encodedTokenLen;
if (false) { // set to true to eagerly check Ptg decoding
LittleEndianByteArrayInputStream in = new LittleEndianByteArrayInputStream(byteEncoding);
Ptg.readTokens(encodedTokenLen, in);
int nUnusedBytes = _byteEncoding.length - in.getReadIndex();
if (nUnusedBytes > 0) {
// TODO - this seems to occur when IntersectionPtg is present
// This example file "IntersectionPtg.xls"
// used by test: TestIntersectionPtg.testReading()
// has 10 bytes unused at the end of the formula
// 10 extra bytes are just 0x01 and 0x00
System.out.println(nUnusedBytes + " unused bytes at end of formula");
}
LittleEndianByteArrayInputStream in = new LittleEndianByteArrayInputStream(byteEncoding);
Ptg.readTokens(encodedTokenLen, in);
int nUnusedBytes = _byteEncoding.length - in.getReadIndex();
if (nUnusedBytes > 0) {
// TODO - this seems to occur when IntersectionPtg is present
// This example file "IntersectionPtg.xls"
// used by test: TestIntersectionPtg.testReading()
// has 10 bytes unused at the end of the formula
// 10 extra bytes are just 0x01 and 0x00
System.out.println(nUnusedBytes + " unused bytes at end of formula");
}
}
}
/**
@ -112,8 +136,8 @@ public class Formula {
* @return Never <code>null</code> (Possibly empty if the supplied <tt>ptgs</tt> is <code>null</code>)
*/
public static Formula create(Ptg[] ptgs) {
if (ptgs == null) {
return new Formula(EMPTY_BYTE_ARRAY, 0);
if (ptgs == null || ptgs.length < 1) {
return EMPTY;
}
int totalSize = Ptg.getEncodedSize(ptgs);
byte[] encodedData = new byte[totalSize];
@ -136,7 +160,7 @@ public class Formula {
}
public Formula copy() {
// OK to return this for the moment because currently immutable
// OK to return this because immutable
return this;
}