Migrated source code from Simantics SVN

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

diff --git a/bundles/org.simantics.compressions/src/org/simantics/compressions/impl/DecompressingInputStream.java b/bundles/org.simantics.compressions/src/org/simantics/compressions/impl/DecompressingInputStream.java
new file mode 100644 (file)
index 0000000..8c79871
--- /dev/null
+++ b/bundles/org.simantics.compressions/src/org/simantics/compressions/impl/DecompressingInputStream.java
@@ -0,0 +1,165 @@
+/*******************************************************************************\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.FileInputStream;\r
+import java.io.FileNotFoundException;\r
+import java.io.IOException;\r
+import java.io.InputStream;\r
+import java.nio.ByteBuffer;\r
+import java.nio.ByteOrder;\r
+import java.nio.IntBuffer;\r
+import java.nio.channels.ReadableByteChannel;\r
+\r
+/**\r
+ * @author Hannu Niemistö\r
+ * @author Tuukka Lehtonen\r
+ */\r
+public abstract class DecompressingInputStream extends InputStream {\r
+\r
+    protected InputStream         stream;\r
+    protected ReadableByteChannel channel;\r
+    protected ByteBuffer          header;\r
+    protected IntBuffer           intHeader;\r
+    protected ByteBuffer          compressed;\r
+    protected ByteBuffer          uncompressed;\r
+    protected byte[]              compressedArray;\r
+\r
+    public DecompressingInputStream(File file) throws FileNotFoundException {\r
+        this(new FileInputStream(file));\r
+    }\r
+\r
+    public DecompressingInputStream(FileInputStream stream) {\r
+        this(stream, stream.getChannel());\r
+    }\r
+\r
+    public DecompressingInputStream(InputStream stream) {\r
+        this(stream, null);\r
+    }\r
+\r
+    public DecompressingInputStream(InputStream stream, ReadableByteChannel channel) {\r
+        this.stream = stream;\r
+        this.channel = channel;\r
+        header = ByteBuffer.allocate(8);\r
+        header.order(ByteOrder.LITTLE_ENDIAN);\r
+        intHeader = header.asIntBuffer();\r
+    }\r
+\r
+    @Override\r
+    public int read() throws IOException {\r
+        if(uncompressed == null || uncompressed.remaining() == 0)\r
+            if(!fillBuffer())\r
+                return -1;\r
+        return uncompressed.get();\r
+    }\r
+\r
+    @Override\r
+    public int read(byte[] b, int off, int len) throws IOException {\r
+        int bytes = 0;\r
+        while(len > 0) {\r
+            if(uncompressed == null || uncompressed.remaining() == 0) {\r
+                if(!fillBuffer()) {\r
+                    return bytes == 0 ? -1 : bytes;\r
+                }\r
+            }\r
+            int s = Math.min(len, uncompressed.remaining());\r
+            uncompressed.get(b, off, s);\r
+            off += s;\r
+            len -= s;\r
+            bytes += s;\r
+        }\r
+        return bytes;\r
+    }\r
+\r
+    @Override\r
+    public void close() throws IOException {\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
+    private boolean fillBuffer() throws IOException {  \r
+        header.position(0);\r
+        if (channel != null) {\r
+            if (Channels.read(channel, header) < 8)\r
+                return false;\r
+        } else {\r
+            if (Channels.readStream(stream, header.array(), 8) < 8)\r
+                return false;\r
+        }\r
+\r
+        intHeader.position(0);\r
+        int compressedSize = intHeader.get();\r
+        int uncompressedSize = intHeader.get();\r
+\r
+        if(uncompressedSize == 0)\r
+            return false;\r
+\r
+        uncompressed = ensureBufferSize(uncompressed, uncompressedSize);\r
+        compressed = ensureBufferSize(compressed, compressedSize);\r
+\r
+        compressed.position(0);\r
+        compressed.limit(compressedSize);\r
+        if (channel != null) {\r
+            if (Channels.read(channel, compressed) < compressedSize)\r
+                return false;\r
+        } else {\r
+            if (compressedArray == null || compressedArray.length < compressedSize) \r
+                compressedArray = new byte[compressedSize];\r
+            if (Channels.readStream(stream, compressedArray, compressedSize) < 8)\r
+                return false;\r
+            compressed.put(compressedArray, 0, compressedSize);\r
+        }\r
+\r
+        decompress(compressed, 0, compressedSize, uncompressed, 0, uncompressedSize);\r
+\r
+        uncompressed.position(0);\r
+        uncompressed.limit(uncompressedSize);\r
+\r
+        return true;\r
+    }\r
+\r
+    private static ByteBuffer ensureBufferSize(ByteBuffer buffer, int minCapacity) {\r
+        int oldCapacity = buffer != null ? buffer.capacity() : 0;\r
+        if (buffer == null || oldCapacity < minCapacity) {\r
+            int newCapacity = grow(oldCapacity, minCapacity);\r
+            //System.out.println("ensureBufferSize(" + oldCapacity + ", " + minCapacity + "), new capacity " + newCapacity);\r
+            buffer = ByteBuffer.allocateDirect(newCapacity);\r
+        }\r
+        return buffer;\r
+    }\r
+\r
+    /**\r
+     * @param oldCapacity current capacity of a buffer\r
+     * @param minCapacity\r
+     * @return new capacity\r
+     */\r
+    private static int grow(int oldCapacity, int minCapacity) {\r
+        // overflow-conscious code\r
+        int newCapacity = oldCapacity + (oldCapacity >> 1);\r
+        if (newCapacity - minCapacity < 0)\r
+            newCapacity = minCapacity;\r
+        if (newCapacity < 0) // overflow\r
+            throw new OutOfMemoryError();\r
+        return newCapacity;\r
+    }\r
+\r
+    public abstract void decompress(ByteBuffer compressed, int compressedOffset, int compressedSize,\r
+            ByteBuffer uncompressed, int uncompressedOffset, int uncompressedSize) throws IOException;\r
+\r
+}
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