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https://github.com/xerial/snappy-java.git
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Fixes issue 26. Add note on using configuration file and license of the embedded libstdc++ library (GCC Runtime Library Exception)
This commit is contained in:
Taro L. Saito
parent
29753d90fd
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1f73c8f21f
16
INSTALL
16
INSTALL
@ -54,7 +54,7 @@ $ make native
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$ make clean-native native
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= Using system installed libsnappyjava (or snappyjava.dll)
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= Using system installed libsnappyjava (or snappyjava.dll) =
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Set org.xerial.snappy.use.systemlib system property to true:
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@ -62,3 +62,17 @@ java -Djava.library.path=(path to the installed snappyjava lib) -Dorg.xerial.sna
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With this setting snappy-java does not use bundled native libraries. Insted it tries to load native library installed at the path specified in java.library.path.
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= Configure snappy-java using property file =
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Prepare org-xerial-snappy.properties file (under the root path of your library) in Java's property file format.
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Here is a list of the available properties:
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* org.xerial.snappy.lib.path (directory containing a snappyjava's native library)
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* org.xerial.snappy.lib.name (library file name)
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* org.xerial.snappy.tempdir (temporary directory to extract a native library bundled in snappy-java)
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* org.xerial.snappy.use.systemlib (if this value is true, use system installed libsnappyjava.so looking the path specified by java.library.path)
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9
NOTICE
9
NOTICE
@ -2,6 +2,13 @@ This product includes software developed by Google
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Snappy: http://code.google.com/p/snappy/ (New BSD License)
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This library containd statically linked libstdc++. This inclusion is allowed by
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"GCC RUntime Library Exception"
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http://gcc.gnu.org/onlinedocs/libstdc++/manual/license.html
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== Contributors ==
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* Tatu Saloranta
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* Providing benchmark suite
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* Alec Wysoker
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* Performance and memory usage improvement
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56
README
56
README
@ -1,22 +1,29 @@
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This document is a copy of http://code.google.com/p/snappy-java/
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---------------------------------------
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The snappy-java is a Java port of the snappy http://code.google.com/p/snappy/, a fast compresser/decompresser (written in C++ developed by Google).
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The snappy-java is a Java port of the snappy http://code.google.com/p/snappy/, a fast compresser/decompresser written in C++ developed by Google.
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== Features ==
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* [http://www.apache.org/licenses/LICENSE-2.0 Apache Licence Version 2.0]. Free for both commercial and non-commercial use!
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* [http://www.apache.org/licenses/LICENSE-2.0 Apache Licence Version 2.0]. Free for both commercial and non-commercial use.
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* Fast compression/decompression tailored to 64-bit CPU architecture.
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* JNI-based implemenation to achieve comparable performance to the native C++ version.
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* Portable across various operating systems; Snappy-java contains the native libraries built for Window/Mac/Linux (32/64-bit). At runtime, snappy-java loads one of these libraries according to your machine environment (It looks system properties, `os.name` and `os.arch`).
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* JNI-based implementation to achieve comparable performance to the native C++ version.
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* Although snappy-java uses JNI, it can be used safely with multiple class loaders (e.g. Tomcat, etc.).
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* Portable across various operating systems; Snappy-java contains native libraries built for Window/Mac/Linux (32/64-bit). At runtime, snappy-java loads one of these libraries according to your machine environment (It looks system properties, `os.name` and `os.arch`).
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* Simple usage. Add the snappy-java-(version).jar file to your classpath. Then call compression/decompression methods in org.xerial.snappy.Snappy.
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== Performance ==
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* Here are some [https://github.com/ning/jvm-compressor-benchmark/wiki benchmark results], comparing snappy-java and the other compressors `LZF`/`QuickLZ`/`Gzip`/`Bzip2`. Thanks [http://twitter.com/#!/cowtowncoder Tatu Saloranta @cowtowncoder] for providing the benchmark suite.
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* Snappy's main target is very high-speed compression/decompression with reasonable compression size. Although the compression ratio of snappy-java is modest and about the same as `LZF` (ranging 20%-100% according to the dataset), among the Java-based compressors in the benchmark snappy-java is as fast as the fastest for compression, and the decompression speed is 2x as fast to the others.
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* Snappy's main target is very high-speed compression/decompression with reasonable compression size. So the compression ratio of snappy-java is modest and about the same as `LZF` (ranging 20%-100% according to the dataset).
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* Here are some [https://github.com/ning/jvm-compressor-benchmark/wiki benchmark results], comparing snappy-java and the other compressors `LZO-java`/`LZF`/`QuickLZ`/`Gzip`/`Bzip2`. Thanks [http://twitter.com/#!/cowtowncoder Tatu Saloranta @cowtowncoder] for providing the benchmark suite.
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* The benchmark result indicates snappy-java is the fastest compreesor/decompressor in Java:
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* http://ning.github.com/jvm-compressor-benchmark/results/canterbury-roundtrip-2011-07-28/index.html
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* The decompression speed is twice as fast as the others:
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* http://ning.github.com/jvm-compressor-benchmark/results/canterbury-uncompress-2011-07-28/index.html
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== Download ==
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The current version 1.0.3 is available from here:
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The current stable version 1.0.3.1 is available from here:
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* Release version: http://maven.xerial.org/repository/artifact/org/xerial/snappy/snappy-java
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* [Milestone] release plans
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* Snapshot version (the latest beta version): http://maven.xerial.org/repository/snapshot/org/xerial/snappy/snappy-java/
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@ -40,7 +47,7 @@ String result = new String(uncompressed, "UTF-8");
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System.out.println(result);
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}}}
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In addition, high-level methods (Snappy.compress(String), Snappy.compress(float[] ..) etc. ) and low-level ones (e.g. Snappy.rawCompress(.. ), Snappy.rawUncompress(..), etc.), which minimize memory copies, can be used. See also
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In addition, high-level methods (`Snappy.compress(String)`, `Snappy.compress(float[] ..)` etc. ) and low-level ones (e.g. `Snappy.rawCompress(.. )`, `Snappy.rawUncompress(..)`, etc.), which minimize memory copies, can be used. See also
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[http://code.google.com/p/snappy-java/source/browse/src/main/java/org/xerial/snappy/Snappy.java Snappy.java]
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===Stream-based API===
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@ -75,7 +82,7 @@ Public discussion forum is here: [http://groups.google.com/group/xerial?hl=en Xe
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== Building from the source code ==
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See the [http://code.google.com/p/snappy-java/source/browse/INSTALL installation instruction]. Building from the source code is an option when JNI-related error (e.g., Java VM crash) is observed in your machine environment. To build snappy-java, you need Mercurial(hg), JDK (1.6 or higher), Maven (3.x or higher is required), g++ compiler (mingw in Windows) etc.
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See the [http://code.google.com/p/snappy-java/source/browse/INSTALL installation instruction]. Building from the source code is an option when your OS platform and CPU architecture is not supported. To build snappy-java, you need Mercurial(hg), JDK (1.6 or higher), Maven (3.x or higher is required), g++ compiler (mingw in Windows) etc.
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{{{
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$ hg clone https://snappy-java.googlecode.com/hg/ snappy-java
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@ -83,36 +90,13 @@ $ cd snappy-java
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$ make
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}}}
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A file `target/snappy-java-$(version).jar` is the product containing the native library built for your platform.
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A file `target/snappy-java-$(version).jar` is the product additionally containing the native library built for your platform.
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==Miscellaneous Notes==
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===Using snappy-java with Tomcat6 Web Server===
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===Using snappy-java with Tomcat 6 (or higher) Web Server===
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Do not include snappy-java-(version).jar in WEB-INF/lib folder of your web application package, since multiple web applications hosted by the same Tomcat server cannot load the snappy-java's native library multiple times due to the specification of JNI (See Section 11.2.4 A Type Safety Restriction http://java.sun.com/docs/books/jni/html/design.html#8628). If Snappy is loaded by different class loaders under the same JVM, you will see `UnsatisfiedLinkError` exception.
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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 in the same JVM by using native code injection to the parent class loader (Issue 21).
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A workaround of this problem is to put snappy-java-(version).jar file into `(TOMCAT_HOME)/lib` direcotry, in which multiple web applications can share the same native library file (.dll, .jnilib, .so) extracted from this snappy-java-(version).jar file.
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If you are using Maven for your web application, set the dependency scope as 'provided', and manually put the snappy-java jar file into (TOMCAT_HOME)/lib folder.
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{{{
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<dependency>
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<groupId>org.xerial.snappy</groupId>
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<artifactId>snappy-java</artifactId>
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<version>(version)</version>
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<scope>provided</scope>
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</dependency>
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}}}
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----
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Snappy-java is developed by [http://www.xerial.org/leo Taro L. Saito]. Twitter [http://twitter.com/#!/taroleo @taroleo]
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[usage]
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* Add snappy-java-(version).jar to your classpath
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* Use the compress/decompress methods defined in org.xerial.snappy.Snappy class.
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== Contributors ==
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* Tatu Saloranta
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* Providing benchmark suite
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* Alec Wysoker
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* Performance and memory usage improvement
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