1 files changed, 75 insertions, 0 deletions
diff --git a/jni-library/src/main/scala/ch/jodersky/jni/NativeLoader.scala b/jni-library/src/main/scala/ch/jodersky/jni/NativeLoader.scala
new file mode 100644
index 0000000..46d4b2d
--- /dev/null
+++ b/jni-library/src/main/scala/ch/jodersky/jni/NativeLoader.scala
@@ -0,0 +1,75 @@
+package ch.jodersky.jni
+
+import java.io.{File, FileOutputStream, InputStream, OutputStream}
+import scala.io.Source
+
+/**
+  * Provides enhanced native library loading functionality. 
+  */
+object NativeLoader {
+
+  /** Name of the shared library file that is contained in a jar. */
+  final val LibraryName = "library"
+
+  final val BufferSize = 4096
+
+  /** Extract a resource from this class loader to a temporary file. */
+  private def extract(path: String): Option[File] = {
+    var in: Option[InputStream] = None
+    var out: Option[OutputStream] = None
+
+    try {
+      in = Option(NativeLoader.getClass.getResourceAsStream(path))
+      if (in.isEmpty) return None
+
+      val file = File.createTempFile(path, "")
+      out = Some(new FileOutputStream(file))
+
+      val buffer = new Array[Byte](BufferSize)
+      var length = -1;
+      do {
+        length = in.get.read(buffer)
+        if (length != -1) out.get.write(buffer, 0, length)
+      } while (length != -1)
+
+      Some(file)
+    } finally {
+      in.foreach(_.close)
+      out.foreach(_.close)
+    }
+  }
+
+  private def loadError(msg: String): Nothing = throw new UnsatisfiedLinkError(
+    "Error during native library extraction " +
+      "(this can happen if your platform is not supported): " +
+      msg
+  )
+
+  def fullLibraryPath(libraryPath: String, platform: Platform) = {
+    libraryPath + "/native/" + platform.id  + "/" + LibraryName
+  }
+
+  private def loadFromJar(libraryPath: String): Unit = {
+    val platform = Platform.current.getOrElse{
+      loadError("Cannot determine current platform.")
+    }
+
+    val resource = fullLibraryPath(libraryPath, platform)
+
+    val file = extract(resource) getOrElse loadError(
+      s"Shared library $resource not found."
+    )
+    System.load(file.getAbsolutePath())
+  }
+
+  /**
+   * Load a native library from the available library path or fall back
+   * to extracting and loading a native library from available resources.
+   */
+  def load(library: String, libraryPath: String): Unit = try {
+    System.loadLibrary(library)
+  } catch {
+    case ex: UnsatisfiedLinkError => loadFromJar(libraryPath)
+  }
+
+}