Author: bodewig
Date: Wed Aug 3 15:16:55 2011
New Revision: 1153535
URL: http://svn.apache.org/viewvc?rev=1153535&view=rev
Log:
Extract the 'search the archive backwards for a signature' logic so it can be
reused to serach for the ZIP64 end of central directory locator
Modified:
commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipFile.java
Modified:
commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipFile.java
URL:
http://svn.apache.org/viewvc/commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipFile.java?rev=1153535&r1=1153534&r2=1153535&view=diff
==============================================================================
---
commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipFile.java
(original)
+++
commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipFile.java
Wed Aug 3 15:16:55 2011
@@ -34,6 +34,8 @@ import java.util.zip.ZipException;
import static org.apache.commons.compress.archivers.zip.ZipConstants.SHORT;
import static org.apache.commons.compress.archivers.zip.ZipConstants.WORD;
+import static
org.apache.commons.compress.archivers.zip.ZipConstants.ZIP64_MAGIC;
+import static
org.apache.commons.compress.archivers.zip.ZipConstants.ZIP64_MAGIC_SHORT;
/**
* Replacement for <code>java.util.ZipFile</code>.
@@ -499,7 +501,7 @@ public class ZipFile {
/* zipfile comment length */ + SHORT;
private static final int MAX_EOCD_SIZE = MIN_EOCD_SIZE
- /* maximum length of zipfile comment */ + 0xFFFF;
+ /* maximum length of zipfile comment */ + ZIP64_MAGIC_SHORT;
private static final int CFD_LOCATOR_OFFSET =
/* end of central dir signature */ WORD
@@ -519,12 +521,30 @@ public class ZipFile {
*/
private void positionAtCentralDirectory()
throws IOException {
+ boolean found = tryToLocateSignature(MIN_EOCD_SIZE, MAX_EOCD_SIZE,
+ ZipArchiveOutputStream.EOCD_SIG);
+ if (!found) {
+ throw new ZipException("archive is not a ZIP archive");
+ }
+ archive.skipBytes(CFD_LOCATOR_OFFSET);
+ byte[] cfdOffset = new byte[WORD];
+ archive.readFully(cfdOffset);
+ archive.seek(ZipLong.getValue(cfdOffset));
+ }
+
+ /**
+ * Searches the archive backwards from minDistance to maxDistance
+ * for the given signature, positions the RandomaccessFile right
+ * at the signature if it has been found.
+ */
+ private boolean tryToLocateSignature(long minDistanceFromEnd,
+ long maxDistanceFromEnd,
+ byte[] sig) throws IOException {
boolean found = false;
- long off = archive.length() - MIN_EOCD_SIZE;
- long stopSearching = Math.max(0L, archive.length() - MAX_EOCD_SIZE);
+ long off = archive.length() - minDistanceFromEnd;
+ long stopSearching = Math.max(0L, archive.length() -
maxDistanceFromEnd);
if (off >= 0) {
archive.seek(off);
- byte[] sig = ZipArchiveOutputStream.EOCD_SIG;
int curr = archive.read();
while (off >= stopSearching && curr != -1) {
if (curr == sig[POS_0]) {
@@ -544,13 +564,10 @@ public class ZipFile {
curr = archive.read();
}
}
- if (!found) {
- throw new ZipException("archive is not a ZIP archive");
+ if (found) {
+ archive.seek(off);
}
- archive.seek(off + CFD_LOCATOR_OFFSET);
- byte[] cfdOffset = new byte[WORD];
- archive.readFully(cfdOffset);
- archive.seek(ZipLong.getValue(cfdOffset));
+ return found;
}
/**
