famibee/SKYNovel

/* ***** BEGIN LICENSE BLOCK *****
    Copyright (c) 2018-2024 Famibee (famibee.blog38.fc2.com)

    This software is released under the MIT License.
    http://opensource.org/licenses/mit-license.php
** ***** END LICENSE BLOCK ***** */

import {IAreas} from './CmnInterface';

export class Areas implements IAreas {
    hAreas    : {[name: string]: number}    = Object.create(null);

    clear() {this.hAreas = {}}

    search(idx: number): boolean {
        return Object.entries(this.hAreas)
        .some(([begin, v])=> (idx >= parseInt(begin) && idx <= v));
    }

    record(idx: number): void {
        if (this.search(idx)) return;

        for (const [begin, v] of Object.entries(this.hAreas)) {
            // 領域末尾+1とマッチ
            if (v +1 === idx) {
                if (String(idx +1) in this.hAreas) {
                    // 二つの領域がマージできる場合
                    this.hAreas[begin] = this.hAreas[idx +1];
                    delete this.hAreas[idx +1]
                }
                else this.hAreas[begin] = idx;
                return;
            }
        }

        // 領域先頭-1とマッチ
        if (String(idx +1) in this.hAreas) {
            this.hAreas[idx] = this.hAreas[idx +1];
            delete this.hAreas[idx +1];
            return;
        }

        this.hAreas[idx] = idx;
    }

    erase(idx: number): void {
        if (! this.search(idx)) return;

        // 領域先頭とマッチ
        if (String(idx) in this.hAreas) {
            if (this.hAreas[idx] > idx) this.hAreas[idx +1] = this.hAreas[idx];
            delete this.hAreas[idx];
            return;
        }

        for (const [begin, v] of Object.entries(this.hAreas)) {
            if (idx < parseInt(begin) || v < idx) continue;

            // 領域末尾とマッチ
            if (this.hAreas[begin] === idx) {
                this.hAreas[begin] = idx -1;
                return;
            }

            // 領域内とマッチ、二つの領域に分割
            this.hAreas[idx +1] = v;
            this.hAreas[begin] = idx -1;
            return;
        }
    }

    get count(): number {return Object.keys(this.hAreas).length}    // 4tst

    toString(): string {
        let ret = '';

        for (const k of Object.keys(this.hAreas)
        .map(k=> parseInt(k))
        .sort((x, y)=> x-y)) {
            ret += k === this.hAreas[k]
            ? ','+ k
            : ','+ k +'~'+ this.hAreas[k];
        }

        return ret;    // 先頭に , が付いている。削除したいが、修正すると互換性に問題あり凍結
    }

}