// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
const buffLength = 1024;
/**
 * looking for the last occurrence of the provided
 * @param file
 * @param target
 * @returns
 */
export const searchFromTheEnd = async (file, target) => {
    const searchWindow = [
        await file.getUint8(file.length - 1n),
        await file.getUint8(file.length - 2n),
        await file.getUint8(file.length - 3n),
        undefined
    ];
    let targetOffset = -1;
    // looking for the last record in the central directory
    let point = file.length - 4n;
    do {
        const prevPoint = point;
        point -= BigInt(buffLength);
        point = point >= 0n ? point : 0n;
        const buff = new Uint8Array(await file.slice(point, prevPoint));
        for (let i = buff.length - 1; i > -1; i--) {
            searchWindow[3] = searchWindow[2];
            searchWindow[2] = searchWindow[1];
            searchWindow[1] = searchWindow[0];
            searchWindow[0] = buff[i];
            if (searchWindow.every((val, index) => val === target[index])) {
                targetOffset = i;
                break;
            }
        }
    } while (targetOffset === -1 && point > 0n);
    return point + BigInt(targetOffset);
};