Merge pull request #338 from AppDevNext/KotlinBuffer

Kotlin buffer

Author: hannesa2

MPChartLib/src/main/java/com/github/mikephil/charting/buffer/AbstractBuffer.java

@@ -0,0 +1,91 @@
+package com.github.mikephil.charting.buffer
+
+/**
+ * Buffer class to boost performance while drawing. Concept: Replace instead of recreate.
+ *
+ * @param <T> The data the buffer accepts to be fed with.
+</T> */
+abstract class AbstractBuffer<T>(size: Int) {
+    /** index in the buffer  */
+    @JvmField
+    protected var index: Int = 0
+
+    /** float-buffer that holds the data points to draw, order: x,y,x,y,...  */
+    @JvmField
+    val buffer: FloatArray
+
+    /** animation phase x-axis  */
+    @JvmField
+    protected var phaseX: Float = 1f
+
+    /** animation phase y-axis  */
+    @JvmField
+    protected var phaseY: Float = 1f
+
+    /** indicates from which x-index the visible data begins  */
+    protected var from: Int = 0
+
+    /** indicates to which x-index the visible data ranges  */
+    protected var to: Int = 0
+
+    /**
+     * Initialization with buffer-size.
+     *
+     * @param size
+     */
+    init {
+        index = 0
+        buffer = FloatArray(size)
+    }
+
+    /** limits the drawing on the x-axis  */
+    fun limitFrom(fromGiven: Int) {
+        from = if (fromGiven < 0)
+            0
+        else
+            fromGiven
+    }
+
+    /** limits the drawing on the x-axis  */
+    fun limitTo(toGiven: Int) {
+        to = if (toGiven < 0)
+            0
+        else
+            toGiven
+    }
+
+    /**
+     * Resets the buffer index to 0 and makes the buffer reusable.
+     */
+    fun reset() {
+        index = 0
+    }
+
+    /**
+     * Returns the size (length) of the buffer array.
+     *
+     * @return
+     */
+    fun size(): Int {
+        return buffer.size
+    }
+
+    /**
+     * Set the phases used for animations.
+     *
+     * @param phaseX
+     * @param phaseY
+     */
+    fun setPhases(phaseX: Float, phaseY: Float) {
+        this.phaseX = phaseX
+        this.phaseY = phaseY
+    }
+
+    /**
+     * Builds up the buffer with the provided data and resets the buffer-index
+     * after feed-completion. This needs to run FAST.
+     *
+     * @param data
+     */
+    abstract fun feed(data: T)
+}