Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.compressions / src / org / simantics / compressions / impl / CompressingOutputStream.java

diff --git a/bundles/org.simantics.compressions/src/org/simantics/compressions/impl/CompressingOutputStream.java b/bundles/org.simantics.compressions/src/org/simantics/compressions/impl/CompressingOutputStream.java
new file mode 100644 (file)
index 0000000..9528835
--- /dev/null
+++ b/bundles/org.simantics.compressions/src/org/simantics/compressions/impl/CompressingOutputStream.java
@@ -0,0 +1,140 @@
+/*******************************************************************************\r
+ * Copyright (c) 2007, 2012 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ *     VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+package org.simantics.compressions.impl;\r
+\r
+import java.io.File;\r
+import java.io.FileNotFoundException;\r
+import java.io.FileOutputStream;\r
+import java.io.IOException;\r
+import java.io.OutputStream;\r
+import java.nio.ByteBuffer;\r
+import java.nio.ByteOrder;\r
+import java.nio.IntBuffer;\r
+import java.nio.channels.WritableByteChannel;\r
+\r
+/**\r
+ * @author Hannu Niemistö\r
+ * @author Tuukka Lehtonen\r
+ */\r
+public abstract class CompressingOutputStream extends OutputStream {\r
+\r
+    protected static final int    BLOCK_SIZE = 1024 * 1024;\r
+\r
+    protected OutputStream        stream;\r
+    protected WritableByteChannel channel;\r
+    protected ByteBuffer          compressed;\r
+    protected byte[]              compressedArray;\r
+    protected ByteBuffer          uncompressed;\r
+    protected IntBuffer           header;\r
+    protected int                 bytes      = 0;\r
+\r
+    public CompressingOutputStream(File file) throws FileNotFoundException {\r
+        this(new FileOutputStream(file));\r
+    }\r
+\r
+    public CompressingOutputStream(FileOutputStream stream) {\r
+        this(stream, stream.getChannel());\r
+    }\r
+\r
+    public CompressingOutputStream(OutputStream stream) {\r
+        this(stream, null);\r
+    }\r
+\r
+    public CompressingOutputStream(OutputStream stream, WritableByteChannel channel) {\r
+        this.stream = stream;\r
+        this.channel = channel;\r
+        uncompressed = allocateBuffer(BLOCK_SIZE);\r
+    }\r
+\r
+    @Override\r
+    public void write(int b) throws IOException {\r
+        if(uncompressed.remaining() == 0)\r
+            flushBuffer();\r
+        uncompressed.put((byte)b);\r
+        ++bytes;\r
+    }\r
+\r
+    @Override\r
+    public void write(byte[] b, int off, int len) throws IOException {\r
+        bytes += len;\r
+        while(len > 0) {\r
+            int s = Math.min(len, uncompressed.remaining());\r
+            uncompressed.put(b, off, s);\r
+            len -= s;\r
+            off += s;\r
+            if(uncompressed.remaining() == 0)\r
+                flushBuffer();\r
+        }\r
+    }\r
+\r
+    @Override\r
+    public void close() throws IOException {\r
+        try {\r
+            flushBuffer();\r
+\r
+            if (channel != null) {\r
+                header.position(0);\r
+                header.put(0);\r
+                header.put(0);\r
+                compressed.position(0);\r
+                compressed.limit(8);\r
+                channel.write(compressed);\r
+            } else if (stream != null) {\r
+                stream.write(new byte[8]);\r
+            }\r
+            //System.out.println("Wrote " + bytes + " uncompressed bytes.");\r
+        } finally {\r
+            if (channel != null) {\r
+                channel.close();\r
+                channel = null;\r
+            }\r
+            if (stream != null) {\r
+                stream.close();\r
+                stream = null;\r
+            }\r
+        }\r
+    }\r
+\r
+    private void flushBuffer() throws IOException {\r
+        int uncompressedSize = uncompressed.position();\r
+        uncompressed.position(0);\r
+        int maxCompressedSize = compressBound(uncompressedSize) + 8;\r
+        if(compressed == null || compressed.capacity() < maxCompressedSize) {\r
+            compressed = allocateBuffer(maxCompressedSize);\r
+            compressed.order(ByteOrder.LITTLE_ENDIAN);\r
+            header = compressed.asIntBuffer();\r
+            if (channel == null)\r
+                compressedArray = new byte[maxCompressedSize];\r
+        }\r
+        int compressedSize = compress(uncompressed, 0, uncompressedSize, \r
+                compressed, 8);\r
+        header.position(0);\r
+        header.put(compressedSize);\r
+        header.put(uncompressedSize);\r
+        compressed.position(0);\r
+        compressed.limit(compressedSize+8);\r
+        if (channel != null) {\r
+            channel.write(compressed);\r
+        } else {\r
+            compressed.get(compressedArray, 0, compressedSize+8);\r
+            stream.write(compressedArray, 0, compressedSize+8);\r
+        }\r
+    }\r
+\r
+    protected abstract int compressBound(int inputSize);\r
+\r
+    protected abstract int compress(ByteBuffer uncompressed, int uncompressedOffset, int uncompressedSize,\r
+            ByteBuffer compressed, int compressedOffset) throws IOException;\r
+\r
+    protected abstract ByteBuffer allocateBuffer(int capacity);\r
+\r
+}
\ No newline at end of file