137 lines
3.8 KiB
JavaScript
137 lines
3.8 KiB
JavaScript
"use strict";
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const baseEncodeTables = {
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26: "abcdefghijklmnopqrstuvwxyz",
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32: "123456789abcdefghjkmnpqrstuvwxyz", // no 0lio
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36: "0123456789abcdefghijklmnopqrstuvwxyz",
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49: "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ", // no lIO
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52: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",
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58: "123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ", // no 0lIO
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62: "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",
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64: "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_",
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};
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/**
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* @param {Uint32Array} uint32Array Treated as a long base-0x100000000 number, little endian
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* @param {number} divisor The divisor
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* @return {number} Modulo (remainder) of the division
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*/
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function divmod32(uint32Array, divisor) {
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let carry = 0;
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for (let i = uint32Array.length - 1; i >= 0; i--) {
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const value = carry * 0x100000000 + uint32Array[i];
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carry = value % divisor;
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uint32Array[i] = Math.floor(value / divisor);
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}
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return carry;
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}
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function encodeBufferToBase(buffer, base, length) {
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const encodeTable = baseEncodeTables[base];
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if (!encodeTable) {
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throw new Error("Unknown encoding base" + base);
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}
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// Input bits are only enough to generate this many characters
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const limit = Math.ceil((buffer.length * 8) / Math.log2(base));
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length = Math.min(length, limit);
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// Most of the crypto digests (if not all) has length a multiple of 4 bytes.
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// Fewer numbers in the array means faster math.
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const uint32Array = new Uint32Array(Math.ceil(buffer.length / 4));
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// Make sure the input buffer data is copied and is not mutated by reference.
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// divmod32() would corrupt the BulkUpdateDecorator cache otherwise.
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buffer.copy(Buffer.from(uint32Array.buffer));
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let output = "";
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for (let i = 0; i < length; i++) {
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output = encodeTable[divmod32(uint32Array, base)] + output;
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}
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return output;
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}
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let crypto = undefined;
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let createXXHash64 = undefined;
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let createMd4 = undefined;
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let BatchedHash = undefined;
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let BulkUpdateDecorator = undefined;
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function getHashDigest(buffer, algorithm, digestType, maxLength) {
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algorithm = algorithm || "xxhash64";
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maxLength = maxLength || 9999;
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let hash;
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if (algorithm === "xxhash64") {
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if (createXXHash64 === undefined) {
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createXXHash64 = require("./hash/xxhash64");
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if (BatchedHash === undefined) {
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BatchedHash = require("./hash/BatchedHash");
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}
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}
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hash = new BatchedHash(createXXHash64());
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} else if (algorithm === "md4") {
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if (createMd4 === undefined) {
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createMd4 = require("./hash/md4");
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if (BatchedHash === undefined) {
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BatchedHash = require("./hash/BatchedHash");
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}
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}
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hash = new BatchedHash(createMd4());
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} else if (algorithm === "native-md4") {
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if (typeof crypto === "undefined") {
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crypto = require("crypto");
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if (BulkUpdateDecorator === undefined) {
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BulkUpdateDecorator = require("./hash/BulkUpdateDecorator");
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}
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}
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hash = new BulkUpdateDecorator(() => crypto.createHash("md4"), "md4");
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} else {
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if (typeof crypto === "undefined") {
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crypto = require("crypto");
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if (BulkUpdateDecorator === undefined) {
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BulkUpdateDecorator = require("./hash/BulkUpdateDecorator");
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}
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}
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hash = new BulkUpdateDecorator(
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() => crypto.createHash(algorithm),
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algorithm
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);
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}
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hash.update(buffer);
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if (
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digestType === "base26" ||
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digestType === "base32" ||
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digestType === "base36" ||
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digestType === "base49" ||
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digestType === "base52" ||
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digestType === "base58" ||
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digestType === "base62" ||
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digestType === "base64safe"
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) {
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return encodeBufferToBase(
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hash.digest(),
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digestType === "base64safe" ? 64 : digestType.substr(4),
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maxLength
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);
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}
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return hash.digest(digestType || "hex").substr(0, maxLength);
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}
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module.exports = getHashDigest;
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