/
KtNDArrayIterator.kt
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/
KtNDArrayIterator.kt
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/*
* Copyright 2019 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jetbrains.numkt.core
import org.jetbrains.numkt.Interpreter.Companion.interpreter
import org.jetbrains.numkt.NumKtException
import java.nio.ByteBuffer
/**
* An iterator for an [KtNDArray]. Returns an view even for one-dimensional arrays.
*/
class NDIterator<T : Any>(pointer: Long) : Iterator<KtNDArray<T>> {
private var ret: KtNDArray<T>? = null
private val iterator: Long = interpreter!!.getIter(pointer)
override fun hasNext(): Boolean {
ret = interpreter!!.iterNext(iterator)
return if (ret != null)
true
else {
interpreter!!.iterDealloc(iterator)
return false
}
}
override fun next(): KtNDArray<T> = ret!!
}
/**
* Iterator over DirectBuffer.
*
* Iterates through a flattened array. This iterator can work with view.
*/
internal class FlatIterator<T : Any>(
private val data: ByteBuffer,
private val ndim: Int,
private val strides: IntArray,
private val itemsize: Int,
private val shape: IntArray,
private val type: Class<T>,
offset: Long
) : Iterator<T> {
private val index = IntArray(ndim)
private val point = offset.toInt()
override fun hasNext(): Boolean {
for (i in 0 until ndim) {
if (index[i] >= shape[i]) {
return false
} else if (index[i] < 0) {
return false
}
}
return true
}
override fun next(): T {
var p = point / itemsize
val res: Any =
when (type) {
Byte::class.javaObjectType -> {
for (i in 0 until ndim) {
p += (strides[i] / itemsize) * index[i]
}
data[p]
}
Short::class.javaObjectType -> {
for (i in 0 until ndim) {
p += (strides[i] / itemsize) * index[i]
}
data.asShortBuffer()[p]
}
Int::class.javaObjectType -> {
for (i in 0 until ndim) {
p += (strides[i] / itemsize) * index[i]
}
data.asIntBuffer()[p]
}
Long::class.javaObjectType -> {
for (i in 0 until ndim) {
p += (strides[i] / itemsize) * index[i]
}
data.asLongBuffer()[p]
}
Float::class.javaObjectType -> {
for (i in 0 until ndim) {
p += (strides[i] / itemsize) * index[i]
}
data.asFloatBuffer()[p]
}
Double::class.javaObjectType -> {
for (i in 0 until ndim) {
p += (strides[i] / itemsize) * index[i]
}
data.asDoubleBuffer()[p]
}
Boolean::class.javaObjectType -> {
for (i in 0 until ndim) {
p += (strides[i] / itemsize) * index[i]
}
data[p] != 0.toByte()
}
Char::class.javaObjectType -> {
for (i in 0 until ndim) {
p += (strides[i] / itemsize) * index[i]
}
data.asIntBuffer()[p].toChar()
}
else -> throw NumKtException("Error to iterating: unknown type")
}
for (i in ndim - 1 downTo 0) {
val t = index[i] + 1
if (t >= shape[i] && i != 0) {
index[i] = 0
} else {
index[i] = t
break
}
}
return res as T
}
}