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Lets-Plot Kotlin API without dependencies.

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/*
 * Copyright (c) 2023 JetBrains s.r.o.
 * Use of this source code is governed by the MIT license that can be found in the LICENSE file.
 *
 * This file has been modified by JetBrains : Java code has been converted to Kotlin code.
 *
 * THE FOLLOWING IS THE COPYRIGHT OF THE ORIGINAL DOCUMENT:
 *
 * Copyright (c) 2009-2012, Hernán J. González.
 * Licensed under the Apache License, Version 2.0.
 *
 * The original PNGJ library is written in Java and can be found here: [PNGJ](https://github.com/leonbloy/pngj).
 */

package org.jetbrains.letsPlot.util.pngj

/**
 * Set of [IImageLine] elements.
 *
 *
 * This is actually a "virtual" set, it can be implemented in several ways; for
 * example
 *
 *  * Cursor-like: stores only one line, which is implicitly moved when
 * requested
 *  * All lines: all lines stored as an array of IImageLine
 *  * Subset of lines: eg, only first 3 lines, or odd numbered lines. Or a band
 * of neighbours lines that is moved like a cursor. The ImageLine that
 * PngReader returns is hosted by a IImageLineSet (this abstraction allows the
 * implementation to deal with interlaced images cleanly) but the library user
 * does not normally needs to know that (or rely on that), except for the
 * [PngReader.readRows] method.
 *
 */
internal interface IImageLineSet {
    /**
     * Asks for imageline corresponding to row n in the original image
     * (zero based). This can trigger side effects in this object (eg, advance a
     * cursor, set current row number...) In some scenarios, this should be
     * consider as alias to (pseudocode)
     * positionAtLine(n); getCurrentLine();
     *
     *
     * Throws exception if not available. The caller is supposed to know what
     * he/she is doing
     */
    fun getImageLine(n: Int): IImageLine

    /**
     * Like [.getImageLine] but uses the raw numbering inside the
     * LineSet This makes little sense for a cursor
     *
     * @param n
     * Should normally go from 0 to [.size]
     * @return
     */
    fun getImageLineRawNum(n: Int): IImageLine

    /**
     * Returns true if the set contain row n (in the original
     * image,zero based) currently allocated.
     *
     *
     * If it's a single-cursor, this should return true only if it's positioned
     * there. (notice that hasImageLine(n) can return false, but getImageLine(n)
     * can be ok)
     *
     */
    fun hasImageLine(n: Int): Boolean

    /**
     * Internal size of allocated rows This is informational, it should rarely
     * be important for the caller.
     */
    fun size(): Int
}