add IO classes

.gitignore

@@ -88,23 +88,23 @@ example/notebooks/.ipynb_checkpoints/*
 
 # Scala package
 # Jetbrain
-mxnet-scala/.idea
+scala-package/.idea
 
 # ctags
-mxnet-scala/tags
+scala-package/tags
 
-mxnet-scala/*.class
-mxnet-scala/*.log
+scala-package/*.class
+scala-package/*.log
 
 # sbt specific
-mxnet-scala/.cache
-mxnet-scala/.lib/
-mxnet-scala/dist/*
-mxnet-scala/target/
-mxnet-scala/lib_managed/
-mxnet-scala/src_managed/
-mxnet-scala/project/boot/
-mxnet-scala/project/plugins/project/
+scala-package/.cache
+scala-package/.lib/
+scala-package/dist/*
+scala-package/target/
+scala-package/lib_managed/
+scala-package/src_managed/
+scala-package/project/boot/
+scala-package/project/plugins/project/
 
 #scala target folders
 scala-package/*/target/
@@ -116,9 +116,7 @@ scala-package/*/*/target/
 .settings
 
 # IDE specific
-mxnet-scala/.scala_dependencies
-mxnet-scala/.worksheet
-mxnet-scala/.idea
-mxnet-scala/*.iml
-
-
+.scala_dependencies
+.worksheet
+.idea
+*.iml

scala-package/core/src/main/scala/ml/dmlc/mxnet/Base.scala

@@ -16,6 +16,7 @@ object Base {
   type MXFloatRef = RefFloat
   type NDArrayHandle = RefLong
   type FunctionHandle = RefLong
+  type DataIterHandle = RefLong
 
   System.loadLibrary("mxnet-scala")
   val _LIB = new LibInfo

scala-package/core/src/main/scala/ml/dmlc/mxnet/IO.scala

@@ -0,0 +1,57 @@
+package ml.dmlc.mxnet
+
+import ml.dmlc.mxnet.Base._
+import ml.dmlc.mxnet.NDArray
+import org.slf4j.LoggerFactory
+
+
+
+abstract class DataIter (val batchSize: Int = 0) {
+  /**
+    * reset the iterator
+    */
+  def reset(): Unit
+  /**
+    * Iterate to next batch
+    * @return whether the move is successful
+    */
+  def iterNext(): Boolean
+
+  /**
+    * get data of current batch
+    * @return the data of current batch
+    */
+  def getData(): NDArray
+
+  /**
+    * Get label of current batch
+    * @return the label of current batch
+    */
+  def getLabel(): NDArray
+
+  /**
+    * get the number of padding examples
+    * in current batch
+    * @return number of padding examples in current batch
+    */
+  def getPad(): Int
+
+  /**
+    * the index of current batch
+    * @return
+    */
+  def getIndex(): Seq[Int]
+}
+
+class MXDataIter(var handle: DataIterHandle) extends DataIter {
+  private val logger = LoggerFactory.getLogger(classOf[MXDataIter])
+
+  def reset(): Unit = {
+    checkCall(_LIB.mxDataIterBeforeFirst(handle))
+  }
+
+  def iterNext(): Boolean = {
+    checkCall(_LIB.mxDataIterNext(handle))
+    return true
+  }
+}

scala-package/core/src/main/scala/ml/dmlc/mxnet/LibInfo.scala

@@ -47,4 +47,12 @@ class LibInfo {
                              start: MXUint,
                              end: MXUint,
                              sliceHandle: NDArrayHandle): Int
+  @native def mxDataIterBeforeFirst(handle: DataIterHandle): Int
+  @native def mxDataIterNext(handle: DataIterHandle): Int
+  @native def mxDataIterGetLabel(handle: DataIterHandle,
+                                 out: NDArrayHandle): Int
+  @native def mxDataIterGetData(handle: DataIterHandle,
+                                out: NDArrayHandle): Int
+  @native def mxDataIterGetPadNum(handle: DataIterHandle,
+                                 out: MXUintRef): Int
 }