Add pure-java Snappy implementation

README.md

@@ -169,6 +169,12 @@ When building on Solaris, use `gmake`:
 A file `target/snappy-java-$(version).jar` is the product additionally containing the native library built for your platform.
 
 ## Miscellaneous Notes
+
+### Using pure-java Snappy implementation
+
+snappy-java can optionally use a pure-java implementation of Snappy based on [aircompressor](https://github.com/airlift/aircompressor/tree/master/src/main/java/io/airlift/compress/snappy). This implementation is selected when no native Snappy library for your platform is found. You can also force using this pure-java implementation by setting a JVM property `org.xerial.snappy.purejava=true` before loading any class of Snappy (e.g., using `-Dorg.xerial.snappy.purejava=true` option when launching JVM).
+
+
 ### Using snappy-java with Tomcat 6 (or higher) Web Server
 
 Simply put the snappy-java's jar to WEB-INF/lib folder of your web application. Usual JNI-library specific problem no longer exists since snappy-java version 1.0.3 or higher can be loaded by multiple class loaders.

build.sbt

@@ -111,7 +111,7 @@ enablePlugins(SbtOsgi)
 
 osgiSettings
 
-OsgiKeys.exportPackage := Seq("org.xerial.snappy", "org.xerial.snappy.buffer", "org.xerial.snappy.pool")
+OsgiKeys.exportPackage := Seq("org.xerial.snappy", "org.xerial.snappy.buffer", "org.xerial.snappy.pool", "org.xerial.snappy.pure")
 OsgiKeys.bundleSymbolicName := "org.xerial.snappy.snappy-java"
 OsgiKeys.bundleActivator := Option("org.xerial.snappy.SnappyBundleActivator")
 OsgiKeys.importPackage := Seq("""org.osgi.framework;version="[1.5,2)"""")

src/main/java/org/xerial/snappy/Snappy.java

@@ -19,11 +19,13 @@
 // Snappy.java
 // Since: 2011/03/29
 //
-// $URL$ 
+// $URL$
 // $Author$
 //--------------------------------------
 package org.xerial.snappy;
 
+import org.xerial.snappy.pure.PureJavaSnappy;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
@@ -43,18 +45,13 @@
 public class Snappy
 {
     static {
-        try {
-            impl = SnappyLoader.loadSnappyApi();
-        }
-        catch (Exception e) {
-            throw new ExceptionInInitializerError(e);
-        }
+        init();
     }
 
     /**
      * An instance of SnappyNative
      */
-    private static SnappyNative impl;
+    private static SnappyApi impl;
 
     /**
      * Clean up a temporary file (native lib) generated by snappy-java.
@@ -69,6 +66,15 @@ public static void cleanUp()
         SnappyLoader.setSnappyApi(null);
     }
 
+    static void init() {
+        try {
+            impl = SnappyLoader.loadSnappyApi();
+        }
+        catch (Exception e) {
+            throw new ExceptionInInitializerError(e);
+        }
+    }
+
     /**
      * Copy bytes from source to destination
      *

src/main/java/org/xerial/snappy/SnappyApi.java

@@ -0,0 +1,60 @@
+package org.xerial.snappy;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+/**
+ * Snappy compressor/decompressor interface. The implementation can be JNI binding or pure-java Snappy implementation.
+ */
+public interface SnappyApi
+{
+    // ------------------------------------------------------------------------
+    // Generic compression/decompression routines.
+    // ------------------------------------------------------------------------
+    long rawCompress(long inputAddr, long inputSize, long destAddr)
+            throws IOException;
+
+    long rawUncompress(long inputAddr, long inputSize, long destAddr)
+            throws IOException;
+
+    int rawCompress(ByteBuffer input, int inputOffset, int inputLength, ByteBuffer compressed,
+            int outputOffset)
+            throws IOException;
+
+    int rawCompress(Object input, int inputOffset, int inputByteLength, Object output, int outputOffset)
+            throws IOException;
+
+    int rawUncompress(ByteBuffer compressed, int inputOffset, int inputLength, ByteBuffer uncompressed,
+            int outputOffset)
+            throws IOException;
+
+    int rawUncompress(Object input, int inputOffset, int inputLength, Object output, int outputOffset)
+            throws IOException;
+
+    // Returns the maximal size of the compressed representation of
+    // input data that is "source_bytes" bytes in length;
+    int maxCompressedLength(int source_bytes);
+
+    // This operation takes O(1) time.
+    int uncompressedLength(ByteBuffer compressed, int offset, int len)
+            throws IOException;
+
+    int uncompressedLength(Object input, int offset, int len)
+            throws IOException;
+
+    long uncompressedLength(long inputAddr, long len)
+            throws IOException;
+
+    boolean isValidCompressedBuffer(ByteBuffer compressed, int offset, int len)
+            throws IOException;
+
+    boolean isValidCompressedBuffer(Object input, int offset, int len)
+            throws IOException;
+
+    boolean isValidCompressedBuffer(long inputAddr, long offset, long len)
+            throws IOException;
+
+    void arrayCopy(Object src, int offset, int byteLength, Object dest, int dOffset)
+            throws IOException;
+
+}

src/main/java/org/xerial/snappy/SnappyErrorCode.java

@@ -41,7 +41,8 @@ public enum SnappyErrorCode
     FAILED_TO_UNCOMPRESS(5),
     EMPTY_INPUT(6),
     INCOMPATIBLE_VERSION(7),
-    INVALID_CHUNK_SIZE(8);
+    INVALID_CHUNK_SIZE(8),
+    UNSUPPORTED_PLATFORM(9);
 
     public final int id;
 

src/main/java/org/xerial/snappy/SnappyLoader.java

@@ -19,11 +19,13 @@
 // SnappyLoader.java
 // Since: 2011/03/29
 //
-// $URL$ 
+// $URL$
 // $Author$
 //--------------------------------------
 package org.xerial.snappy;
 
+import org.xerial.snappy.pure.PureJavaSnappy;
+
 import java.io.*;
 import java.net.URL;
 import java.util.Enumeration;
@@ -75,13 +77,14 @@ public class SnappyLoader
     public static final String SNAPPY_SYSTEM_PROPERTIES_FILE = "org-xerial-snappy.properties";
     public static final String KEY_SNAPPY_LIB_PATH = "org.xerial.snappy.lib.path";
     public static final String KEY_SNAPPY_LIB_NAME = "org.xerial.snappy.lib.name";
+    public static final String KEY_SNAPPY_PUREJAVA = "org.xerial.snappy.purejava";
     public static final String KEY_SNAPPY_TEMPDIR = "org.xerial.snappy.tempdir";
     public static final String KEY_SNAPPY_USE_SYSTEMLIB = "org.xerial.snappy.use.systemlib";
     public static final String KEY_SNAPPY_DISABLE_BUNDLED_LIBS = "org.xerial.snappy.disable.bundled.libs"; // Depreciated, but preserved for backward compatibility
 
     private static boolean isLoaded = false;
 
-    private static volatile SnappyNative snappyApi = null;
+    private static volatile SnappyApi snappyApi = null;
     private static volatile BitShuffleNative bitshuffleApi = null;
 
     private static File nativeLibFile = null;
@@ -101,11 +104,11 @@ static void cleanUpExtractedNativeLib()
     /**
      * Set the `snappyApi` instance.
      *
-     * @param nativeCode
+     * @param apiImpl
      */
-    static synchronized void setSnappyApi(SnappyNative nativeCode)
+    static synchronized void setSnappyApi(SnappyApi apiImpl)
     {
-        snappyApi = nativeCode;
+        snappyApi = apiImpl;
     }
 
     /**
@@ -146,13 +149,29 @@ private static void loadSnappySystemProperties()
         loadSnappySystemProperties();
     }
 
-    static synchronized SnappyNative loadSnappyApi()
+    static synchronized boolean isPureJava() {
+        return snappyApi != null && PureJavaSnappy.class.isAssignableFrom(snappyApi.getClass());
+    }
+
+    static synchronized SnappyApi loadSnappyApi()
     {
         if (snappyApi != null) {
             return snappyApi;
         }
-        loadNativeLibrary();
-        setSnappyApi(new SnappyNative());
+        try {
+            if(Boolean.parseBoolean(System.getProperty(KEY_SNAPPY_PUREJAVA, "false"))) {
+                // Use pure-java Snappy implementation
+                setSnappyApi(new PureJavaSnappy());
+            }
+            else {
+                loadNativeLibrary();
+                setSnappyApi(new SnappyNative());
+            }
+        }
+        catch(Exception e) {
+            // Fall-back to pure-java Snappy implementation
+            setSnappyApi(new PureJavaSnappy());
+        }
         return snappyApi;
     }
 
@@ -311,7 +330,7 @@ static File findNativeLibrary()
         String snappyNativeLibraryPath = System.getProperty(KEY_SNAPPY_LIB_PATH);
         String snappyNativeLibraryName = System.getProperty(KEY_SNAPPY_LIB_NAME);
 
-        // Resolve the library file name with a suffix (e.g., dll, .so, etc.) 
+        // Resolve the library file name with a suffix (e.g., dll, .so, etc.)
         if (snappyNativeLibraryName == null) {
             snappyNativeLibraryName = System.mapLibraryName("snappyjava");
         }

src/main/java/org/xerial/snappy/SnappyNative.java

@@ -19,7 +19,7 @@
 // SnappyNative.java
 // Since: 2011/03/30
 //
-// $URL$ 
+// $URL$
 // $Author$
 //--------------------------------------
 package org.xerial.snappy;
@@ -38,57 +38,71 @@
  *
  * @author leo
  */
-public class SnappyNative
+public class SnappyNative implements SnappyApi
 {
 
     public native String nativeLibraryVersion();
 
     // ------------------------------------------------------------------------
     // Generic compression/decompression routines.
     // ------------------------------------------------------------------------
+    @Override
     public native long rawCompress(long inputAddr, long inputSize, long destAddr)
             throws IOException;
 
+    @Override
     public native long rawUncompress(long inputAddr, long inputSize, long destAddr)
             throws IOException;
 
+    @Override
     public native int rawCompress(ByteBuffer input, int inputOffset, int inputLength, ByteBuffer compressed,
             int outputOffset)
             throws IOException;
 
+    @Override
     public native int rawCompress(Object input, int inputOffset, int inputByteLength, Object output, int outputOffset)
             throws IOException;
 
+    @Override
     public native int rawUncompress(ByteBuffer compressed, int inputOffset, int inputLength, ByteBuffer uncompressed,
             int outputOffset)
             throws IOException;
 
+    @Override
     public native int rawUncompress(Object input, int inputOffset, int inputLength, Object output, int outputOffset)
             throws IOException;
 
     // Returns the maximal size of the compressed representation of
     // input data that is "source_bytes" bytes in length;
+    @Override
     public native int maxCompressedLength(int source_bytes);
 
     // This operation takes O(1) time.
+    @Override
     public native int uncompressedLength(ByteBuffer compressed, int offset, int len)
             throws IOException;
 
+    @Override
     public native int uncompressedLength(Object input, int offset, int len)
             throws IOException;
 
+    @Override
     public native long uncompressedLength(long inputAddr, long len)
             throws IOException;
 
+    @Override
     public native boolean isValidCompressedBuffer(ByteBuffer compressed, int offset, int len)
             throws IOException;
 
+    @Override
     public native boolean isValidCompressedBuffer(Object input, int offset, int len)
             throws IOException;
 
+    @Override
     public native boolean isValidCompressedBuffer(long inputAddr, long offset, long len)
             throws IOException;
 
+    @Override
     public native void arrayCopy(Object src, int offset, int byteLength, Object dest, int dOffset)
             throws IOException;