nxkit/large_file_cut.js

This is a collection of tools, independent of any other libraries

"use strict";
/* ***** BEGIN LICENSE BLOCK *****
 * Distributed under the BSD license:
 *
 * Copyright (c) 2015, xuewen.chu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of xuewen.chu nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL xuewen.chu BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ***** END LICENSE BLOCK ***** */
Object.defineProperty(exports, "__esModule", { value: true });
const fs = require("./fs");
function cut(filename, count) {
    count = Math.max(2, Math.min(count, 100));
    var stat = fs.statSync(filename);
    var size = stat.size / count;
    var rfd = fs.openSync(filename, 'r');
    var wfd = fs.openSync(filename + '.0', 'w');
    var index = 0;
    var buff = Buffer.alloc(1024 * 100); // 100kb
    var len = 0;
    var total = 0;
    do {
        if (total >= size) { // reset
            index++;
            total = 0;
            fs.closeSync(wfd);
            wfd = fs.openSync(filename + '.' + index, 'w');
        }
        len = fs.readSync(rfd, buff, 0, buff.length, null);
        fs.writeSync(wfd, buff, 0, len, null);
        total += len;
    } while (len == buff.length);
    fs.closeSync(rfd);
    fs.closeSync(wfd);
}
exports.cut = cut;
function merge(filename, options) {
    options = Object.assign({
        target: filename,
        removeSource: false,
    }, options);
    var wfd = fs.openSync(options.target, 'w');
    var buff = Buffer.alloc(1024 * 100); // 100kb
    var len = 0;
    var i = 0;
    for (; fs.existsSync(filename + '.' + i); i++) {
        var rfd = fs.openSync(filename + '.' + i, 'r');
        do {
            len = fs.readSync(rfd, buff, 0, buff.length, null);
            fs.writeSync(wfd, buff, 0, len, null);
        } while (len == buff.length);
        fs.closeSync(rfd);
        if (options.removeSource) { // delete
            fs.removerSync(filename + '.' + i);
        }
    }
    fs.closeSync(wfd);
    return i;
}
exports.merge = merge;