Integrata aggiunta "Extracting InputStream directly" di daniel-rabe

edmund-wagner/junrar#34

I did some changes to JunRar to extract InputStreams directly, without
the need to write it in a File first.

My project loads files from websides (e.g. RAR-Files), the results are
InputStreams of that files. When I want to know what is inside a
RAR-File I don't want to write that InputStream in a File everytime, so
I made this little changes to junrar.

greets Daniel Rabe

Author: albertus82

src/main/java/com/github/junrar/Archive.java

@@ -33,6 +33,7 @@
 import com.github.junrar.exception.RarException;
 import com.github.junrar.exception.RarException.RarExceptionType;
 import com.github.junrar.impl.FileVolumeManager;
+import com.github.junrar.impl.InputStreamVolumeManager;
 import com.github.junrar.io.IReadOnlyAccess;
 import com.github.junrar.rarfile.AVHeader;
 import com.github.junrar.rarfile.BaseBlock;
@@ -118,6 +119,15 @@ public Archive(File firstVolume, UnrarCallback unrarCallback)
 		this(new FileVolumeManager(firstVolume), unrarCallback);
 	}
 
+	public Archive(InputStream firstVolume) throws RarException, IOException {
+		this(new InputStreamVolumeManager(firstVolume), null);
+	}
+
+	public Archive(InputStream firstVolume, UnrarCallback unrarCallback)
+			throws RarException, IOException {
+		this(new InputStreamVolumeManager(firstVolume), unrarCallback);
+	}
+
 	// public File getFile() {
 	// return file;
 	// }

src/main/java/com/github/junrar/impl/InputStreamVolume.java

@@ -0,0 +1,60 @@
+package com.github.junrar.impl;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+import com.github.junrar.Archive;
+import com.github.junrar.Volume;
+import com.github.junrar.io.IReadOnlyAccess;
+import com.github.junrar.io.ReadOnlyAccessByteArray;
+
+
+/**
+ * @author Daniel Rabe</a>
+ * 
+ */
+public class InputStreamVolume implements Volume {
+	private final Archive archive;
+	private final byte[] file;
+
+	/**
+	 * @param file
+	 * @throws IOException 
+	 */
+	public InputStreamVolume(Archive archive, InputStream inputstream) throws IOException {
+		this.archive = archive;
+		byte[] buff = new byte[8000];
+		int bytesRead = 0;
+		ByteArrayOutputStream bao = new ByteArrayOutputStream();
+		while((bytesRead = inputstream.read(buff)) != -1) {
+			bao.write(buff, 0, bytesRead);
+		}
+		byte[] data = bao.toByteArray();
+		this.file = data;
+	}
+
+	@Override
+	public IReadOnlyAccess getReadOnlyAccess() throws IOException {
+        return new ReadOnlyAccessByteArray(file);
+	}
+
+	@Override
+	public long getLength() {
+		return file.length;
+	}
+
+	@Override
+	public Archive getArchive() {
+		return archive;
+	}
+
+	/**
+	 * @return the file
+	 */
+	public File getFile() {
+		// there is no File object anymore
+		return null;
+	}
+}

src/main/java/com/github/junrar/impl/InputStreamVolumeManager.java

@@ -0,0 +1,39 @@
+package com.github.junrar.impl;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+import com.github.junrar.Archive;
+import com.github.junrar.Volume;
+import com.github.junrar.VolumeManager;
+import com.github.junrar.util.VolumeHelper;
+
+
+/**
+ * @author Daniel Rabe</a>
+ * 
+ */
+public class InputStreamVolumeManager implements VolumeManager {
+	private final InputStream firstVolume;
+
+	public InputStreamVolumeManager(InputStream firstVolume) {
+		this.firstVolume = firstVolume;
+	}
+
+	@Override
+	public Volume nextArchive(Archive archive, Volume last)
+			throws IOException {
+		if (last == null)
+			return new InputStreamVolume(archive, firstVolume);
+
+		FileVolume lastFileVolume = (FileVolume) last;
+		boolean oldNumbering = !archive.getMainHeader().isNewNumbering()
+				|| archive.isOldFormat();
+		String nextName = VolumeHelper.nextVolumeName(lastFileVolume.getFile()
+				.getAbsolutePath(), oldNumbering);
+		File nextVolume = new File(nextName);
+
+		return new FileVolume(archive, nextVolume);
+	}
+}