Adding JMCR-Stable version

[Benchmarks_CSolver.git] / JMCR-Stable / real-world application / MyDerby-10.3 / java / engine / org / apache / derby / impl / store / raw / data / DecryptInputStream.java

diff --git a/JMCR-Stable/real-world application/MyDerby-10.3/java/engine/org/apache/derby/impl/store/raw/data/DecryptInputStream.java b/JMCR-Stable/real-world application/MyDerby-10.3/java/engine/org/apache/derby/impl/store/raw/data/DecryptInputStream.java
new file mode 100644 (file)
index 0000000..3a429a7
--- /dev/null
+++ b/JMCR-Stable/real-world application/MyDerby-10.3/java/engine/org/apache/derby/impl/store/raw/data/DecryptInputStream.java
@@ -0,0 +1,92 @@
+/*\r
+\r
+   Derby - Class org.apache.derby.impl.store.raw.data.DecryptInputStream\r
+\r
+   Licensed to the Apache Software Foundation (ASF) under one or more\r
+   contributor license agreements.  See the NOTICE file distributed with\r
+   this work for additional information regarding copyright ownership.\r
+   The ASF licenses this file to you under the Apache License, Version 2.0\r
+   (the "License"); you may not use this file except in compliance with\r
+   the License.  You may obtain a copy of the License at\r
+\r
+      http://www.apache.org/licenses/LICENSE-2.0\r
+\r
+   Unless required by applicable law or agreed to in writing, software\r
+   distributed under the License is distributed on an "AS IS" BASIS,\r
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
+   See the License for the specific language governing permissions and\r
+   limitations under the License.\r
+\r
+ */\r
+\r
+package org.apache.derby.impl.store.raw.data;\r
+\r
+import org.apache.derby.iapi.error.StandardException;\r
+import org.apache.derby.iapi.store.raw.data.DataFactory;\r
+import org.apache.derby.iapi.store.raw.RawStoreFactory;\r
+\r
+import org.apache.derby.iapi.services.io.CompressedNumber;\r
+\r
+import java.io.InputStream;\r
+import java.io.IOException;\r
+\r
+/**\r
+       A DecryptInputStream is used by stream container to access an encrypted\r
+       stream of bytes.\r
+*/\r
+public class DecryptInputStream extends BufferedByteHolderInputStream {\r
+\r
+       // if database is encrypted, bytes to reserve at the beginning of the buffer\r
+       //protected static final int ENCRYPTION_RESERVE = dataFactory.getEncryptionBlockSize() - 1;\r
+\r
+       protected DataFactory dataFactory;\r
+       protected InputStream in;\r
+\r
+       public DecryptInputStream(InputStream in, ByteHolder bh, DataFactory dataFactory)\r
+               throws IOException {\r
+\r
+               super(bh);\r
+               this.in = in;\r
+               this.dataFactory = dataFactory;\r
+               fillByteHolder();\r
+       }\r
+\r
+       public void fillByteHolder() throws IOException {\r
+\r
+               if (this.bh.available() == 0) {\r
+\r
+                       this.bh.clear();\r
+\r
+                       try {\r
+                               // from the stream, read the actual length of the bytes\r
+                               // before it was padded and encrypted.\r
+                               int realLen = CompressedNumber.readInt(in);\r
+                               // if it is -1, we have reached the end of the file.\r
+                               // then we are done.\r
+                               if (realLen == -1)\r
+                                       return;\r
+\r
+                               // calculate out what the padding was based on the actual length\r
+                               int tail = realLen % dataFactory.getEncryptionBlockSize();\r
+                               int padding = (tail == 0) ? 0 : (dataFactory.getEncryptionBlockSize() - tail);\r
+                               int encryptedLen = realLen + padding;\r
+\r
+                               // read all encrypted data including the padding.\r
+                               byte[] ciphertext = new byte[encryptedLen];\r
+                               in.read(ciphertext, 0, encryptedLen);\r
+                               byte[] cleartext = new byte[encryptedLen];\r
+                               // decrypt the data, and stored it in a new byte array.\r
+                               dataFactory.decrypt(ciphertext, 0, encryptedLen, cleartext, 0);\r
+\r
+                               // only put the actual data without the padding into the byte holder.\r
+                               bh.write(cleartext, padding, realLen);\r
+\r
+                       } catch (StandardException se) {\r
+                               throw new IOException();\r
+                       }\r
+\r
+                       // allow reading from the byte holder.\r
+                       this.bh.startReading();\r
+               }\r
+       }\r
+}\r