Merge pull request #14 from trevorr/develop

Merging ARM support, contributed by Trevor

Makefile

@@ -82,7 +82,11 @@ test: $(NATIVE_DLL)
 	$(MVN) test
 
 win32: 
-	$(MAKE) native CXX=mingw32-g++ OS_NAME=Windows OS_ARCH=x86  
+	$(MAKE) native CROSS_PREFIX=i686-w64-mingw32- OS_NAME=Windows OS_ARCH=x86
+
+# for cross-compilation on Ubuntu, install the g++-mingw-w64-x86-64 package
+win64:
+	$(MAKE) native CROSS_PREFIX=x86_64-w64-mingw32- OS_NAME=Windows OS_ARCH=amd64
 
 mac32: 
 	$(MAKE) native OS_NAME=Mac OS_ARCH=i386
@@ -90,6 +94,14 @@ mac32:
 linux32:
 	$(MAKE) native OS_NAME=Linux OS_ARCH=i386
 
+# for cross-compilation on Ubuntu, install the g++-arm-linux-gnueabi package
+linux-arm:
+	$(MAKE) native CROSS_PREFIX=arm-linux-gnueabi- OS_NAME=Linux OS_ARCH=arm
+
+# for cross-compilation on Ubuntu, install the g++-arm-linux-gnueabihf package
+linux-armhf:
+	$(MAKE) native CROSS_PREFIX=arm-linux-gnueabihf- OS_NAME=Linux OS_ARCH=armhf
+
 clean-native-linux32:
 	$(MAKE) clean-native OS_NAME=Linux OS_ARCH=i386
 

Makefile.common

@@ -105,15 +105,15 @@ Mac-x86_64_LINKFLAGS := -dynamiclib -static-libgcc
 Mac-x86_64_LIBNAME   := libsnappyjava.jnilib 
 Mac-x86_64_SNAPPY_FLAGS  := 
 
-Windows-x86_CXX          := mingw32-g++
-Windows-x86_STRIP        := strip
+Windows-x86_CXX          := $(CROSS_PREFIX)g++
+Windows-x86_STRIP        := $(CROSS_PREFIX)strip
 Windows-x86_CXXFLAGS     := -Ilib/inc_win -O2 
 Windows-x86_LINKFLAGS    := -Wl,--kill-at -shared -static
 Windows-x86_LIBNAME      := snappyjava.dll
 Windows-x86_SNAPPY_FLAGS := 
 
-Windows-amd64_CXX          := x86_64-w64-mingw32-g++
-Windows-amd64_STRIP        := x86_64-w64-mingw32-strip
+Windows-amd64_CXX          := $(CROSS_PREFIX)g++
+Windows-amd64_STRIP        := $(CROSS_PREFIX)strip
 Windows-amd64_CXXFLAGS     := -Ilib/inc_win -O2 
 Windows-amd64_LINKFLAGS    := -Wl,--kill-at -shared -static 
 Windows-amd64_LIBNAME      := snappyjava.dll

README.md

@@ -90,6 +90,23 @@ See the [installation instruction](https://github.com/xerial/snappy-java/blob/de
 
 A file `target/snappy-java-$(version).jar` is the product additionally containing the native library built for your platform.
 
+## Cross-compiling for other platforms
+The Makefile contains rules for cross-compiling the native library for other platforms so that the snappy-java JAR can support multiple platforms. For example, to build the native libraries for x86 Linux, x86 and x86-64 Windows, and soft- and hard-float ARM:
+
+    $ make linux32 win32 win64 linux-arm linux-armhf
+
+If you append `snappy` to the line above, it will also build the native library for the current platform and then build the snappy-java JAR (containing all native libraries built so far).
+
+Of course, you must first have the necessary cross-compilers and development libraries installed for each target CPU and OS. For example, on Ubuntu 12.04 for x86-64, install the following packages for each target:
+
+  * linux32: `sudo apt-get install g++-multilib libc6-dev-i386 lib32stdc++6`
+  * win32: `sudo apt-get install g++-mingw-w64-i686`
+  * win64: `sudo apt-get install g++-mingw-w64-x86-64`
+  * arm: `sudo apt-get install g++-arm-linux-gnueabi`
+  * armhf: `sudo apt-get install g++-arm-linux-gnueabihf`
+
+Unfortunately, cross-compiling for Mac OS X is not currently possible; you must compile within OS X.
+
 ## Miscellaneous Notes
 ### Using snappy-java with Tomcat 6 (or higher) Web Server