app/node_modules/qiniu-js/esm/utils/crc32.js

/* eslint-disable no-bitwise */
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
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        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
var __generator = (this && this.__generator) || function (thisArg, body) {
    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
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            if (y = 0, t) op = [op[0] & 2, t.value];
            switch (op[0]) {
                case 0: case 1: t = op; break;
                case 4: _.label++; return { value: op[1], done: false };
                case 5: _.label++; y = op[1]; op = [0]; continue;
                case 7: op = _.ops.pop(); _.trys.pop(); continue;
                default:
                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
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        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
    }
};
import { MB } from './helper';
/**
 * 以下 class 实现参考
 * https://github.com/Stuk/jszip/blob/d4702a70834bd953d4c2d0bc155fad795076631a/lib/crc32.js
 * 该实现主要针对大文件优化、对计算的值进行了 `>>> 0` 运算（为与服务端保持一致）
 */
var CRC32 = /** @class */ (function () {
    function CRC32() {
        this.crc = -1;
        this.table = this.makeTable();
    }
    CRC32.prototype.makeTable = function () {
        var table = new Array();
        for (var i = 0; i < 256; i++) {
            var t = i;
            for (var j = 0; j < 8; j++) {
                if (t & 1) {
                    // IEEE 标准
                    t = (t >>> 1) ^ 0xEDB88320;
                }
                else {
                    t >>>= 1;
                }
            }
            table[i] = t;
        }
        return table;
    };
    CRC32.prototype.append = function (data) {
        var crc = this.crc;
        for (var offset = 0; offset < data.byteLength; offset++) {
            crc = (crc >>> 8) ^ this.table[(crc ^ data[offset]) & 0xFF];
        }
        this.crc = crc;
    };
    CRC32.prototype.compute = function () {
        return (this.crc ^ -1) >>> 0;
    };
    CRC32.prototype.readAsUint8Array = function (file) {
        return __awaiter(this, void 0, void 0, function () {
            var _a;
            return __generator(this, function (_b) {
                switch (_b.label) {
                    case 0:
                        if (!(typeof file.arrayBuffer === 'function')) return [3 /*break*/, 2];
                        _a = Uint8Array.bind;
                        return [4 /*yield*/, file.arrayBuffer()];
                    case 1: return [2 /*return*/, new (_a.apply(Uint8Array, [void 0, _b.sent()]))()];
                    case 2: return [2 /*return*/, new Promise(function (resolve, reject) {
                            var reader = new FileReader();
                            reader.onload = function () {
                                if (reader.result == null) {
                                    reject();
                                    return;
                                }
                                if (typeof reader.result === 'string') {
                                    reject();
                                    return;
                                }
                                resolve(new Uint8Array(reader.result));
                            };
                            reader.readAsArrayBuffer(file);
                        })];
                }
            });
        });
    };
    CRC32.prototype.file = function (file) {
        return __awaiter(this, void 0, void 0, function () {
            var _a, count, index, start, end, chuck;
            return __generator(this, function (_b) {
                switch (_b.label) {
                    case 0:
                        if (!(file.size <= MB)) return [3 /*break*/, 2];
                        _a = this.append;
                        return [4 /*yield*/, this.readAsUint8Array(file)];
                    case 1:
                        _a.apply(this, [_b.sent()]);
                        return [2 /*return*/, this.compute()];
                    case 2:
                        count = Math.ceil(file.size / MB);
                        index = 0;
                        _b.label = 3;
                    case 3:
                        if (!(index < count)) return [3 /*break*/, 6];
                        start = index * MB;
                        end = index === (count - 1) ? file.size : start + MB;
                        return [4 /*yield*/, this.readAsUint8Array(file.slice(start, end))];
                    case 4:
                        chuck = _b.sent();
                        this.append(new Uint8Array(chuck));
                        _b.label = 5;
                    case 5:
                        index++;
                        return [3 /*break*/, 3];
                    case 6: return [2 /*return*/, this.compute()];
                }
            });
        });
    };
    CRC32.file = function (file) {
        var crc = new CRC32();
        return crc.file(file);
    };
    return CRC32;
}());
export { CRC32 };
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