Adding jtar

[gigi.git] / lib / jtar / org / kamranzafar / jtar / TarOutputStream.java

diff --git a/lib/jtar/org/kamranzafar/jtar/TarOutputStream.java b/lib/jtar/org/kamranzafar/jtar/TarOutputStream.java
new file mode 100644 (file)
index 0000000..e17413c
--- /dev/null
+++ b/lib/jtar/org/kamranzafar/jtar/TarOutputStream.java
@@ -0,0 +1,163 @@
+/**
+ * Copyright 2012 Kamran Zafar 
+ * 
+ * Licensed 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.kamranzafar.jtar;
+
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.RandomAccessFile;
+
+/**
+ * @author Kamran Zafar
+ * 
+ */
+public class TarOutputStream extends OutputStream {
+       private final OutputStream out;
+    private long bytesWritten;
+    private long currentFileSize;
+    private TarEntry currentEntry;
+
+    public TarOutputStream(OutputStream out) {
+        this.out = out;
+        bytesWritten = 0;
+        currentFileSize = 0;
+    }
+
+       public TarOutputStream(final File fout) throws FileNotFoundException {
+               this.out = new BufferedOutputStream(new FileOutputStream(fout));
+               bytesWritten = 0;
+               currentFileSize = 0;
+       }
+
+       /**
+        * Opens a file for writing. 
+        */
+       public TarOutputStream(final File fout, final boolean append) throws IOException {
+               @SuppressWarnings("resource")
+               RandomAccessFile raf = new RandomAccessFile(fout, "rw");
+               final long fileSize = fout.length();
+               if (append && fileSize > TarConstants.EOF_BLOCK) {
+                       raf.seek(fileSize - TarConstants.EOF_BLOCK);
+               }
+               out = new BufferedOutputStream(new FileOutputStream(raf.getFD()));
+       }
+
+    /**
+     * Appends the EOF record and closes the stream
+     * 
+     * @see java.io.FilterOutputStream#close()
+     */
+    @Override
+    public void close() throws IOException {
+        closeCurrentEntry();
+        write( new byte[TarConstants.EOF_BLOCK] );
+        out.close();
+    }
+    /**
+     * Writes a byte to the stream and updates byte counters
+     * 
+     * @see java.io.FilterOutputStream#write(int)
+     */
+    @Override
+    public void write(int b) throws IOException {
+        out.write( b );
+        bytesWritten += 1;
+
+        if (currentEntry != null) {
+            currentFileSize += 1;
+        }
+    }
+
+    /**
+     * Checks if the bytes being written exceed the current entry size.
+     * 
+     * @see java.io.FilterOutputStream#write(byte[], int, int)
+     */
+    @Override
+    public void write(byte[] b, int off, int len) throws IOException {
+        if (currentEntry != null && !currentEntry.isDirectory()) {
+            if (currentEntry.getSize() < currentFileSize + len) {
+                throw new IOException( "The current entry[" + currentEntry.getName() + "] size["
+                        + currentEntry.getSize() + "] is smaller than the bytes[" + ( currentFileSize + len )
+                        + "] being written." );
+            }
+        }
+
+        out.write( b, off, len );
+        
+        bytesWritten += len;
+
+        if (currentEntry != null) {
+            currentFileSize += len;
+        }        
+    }
+
+    /**
+     * Writes the next tar entry header on the stream
+     * 
+     * @param entry
+     * @throws IOException
+     */
+    public void putNextEntry(TarEntry entry) throws IOException {
+        closeCurrentEntry();
+
+        byte[] header = new byte[TarConstants.HEADER_BLOCK];
+        entry.writeEntryHeader( header );
+
+        write( header );
+
+        currentEntry = entry;
+    }
+
+    /**
+     * Closes the current tar entry
+     * 
+     * @throws IOException
+     */
+    protected void closeCurrentEntry() throws IOException {
+        if (currentEntry != null) {
+            if (currentEntry.getSize() > currentFileSize) {
+                throw new IOException( "The current entry[" + currentEntry.getName() + "] of size["
+                        + currentEntry.getSize() + "] has not been fully written." );
+            }
+
+            currentEntry = null;
+            currentFileSize = 0;
+
+            pad();
+        }
+    }
+
+    /**
+     * Pads the last content block
+     * 
+     * @throws IOException
+     */
+    protected void pad() throws IOException {
+        if (bytesWritten > 0) {
+            int extra = (int) ( bytesWritten % TarConstants.DATA_BLOCK );
+
+            if (extra > 0) {
+                write( new byte[TarConstants.DATA_BLOCK - extra] );
+            }
+        }
+    }
+}