svn commit: r759807 - /commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipArchiveInputStream.java

[se...@apache.org]

Author: sebb
Date: Mon Mar 30 00:39:05 2009
New Revision: 759807

URL: http://svn.apache.org/viewvc?rev=759807&view=rev
Log:
Empty Zip files start with End of Central directory

Modified:
    commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipArchiveInputStream.java

Modified: commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipArchiveInputStream.java
URL: http://svn.apache.org/viewvc/commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipArchiveInputStream.java?rev=759807&r1=759806&r2=759807&view=diff
==============================================================================
--- commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipArchiveInputStream.java (original)
+++ commons/proper/compress/trunk/src/main/java/org/apache/commons/compress/archivers/zip/ZipArchiveInputStream.java Mon Mar 30 00:39:05 2009
@@ -266,18 +266,26 @@
         throw new IllegalArgumentException();
     }
 
+    /*
+     *  This test assumes that the zip file does not have any additional leading content,
+     *  which is something that is allowed by the specification (e.g. self-extracting zips)
+     */
     public static boolean matches(byte[] signature, int length) {
         if (length < ZipArchiveOutputStream.LFH_SIG.length) {
             return false;
         }
 
-        for (int i = 0; i < ZipArchiveOutputStream.LFH_SIG.length; i++) {
-            if (signature[i] != ZipArchiveOutputStream.LFH_SIG[i]) {
+        return checksig(signature, ZipArchiveOutputStream.LFH_SIG) // normal file
+            || checksig(signature, ZipArchiveOutputStream.EOCD_SIG); // empty zip
+    }
+
+    private static boolean checksig(byte[] signature, byte[] expected){
+        for (int i = 0; i < expected.length; i++) {
+            if (signature[i] != expected[i]) {
                 return false;
             }
         }
-
-        return true;
+        return true;        
     }
 
     private void closeEntry() throws IOException {