54 lines
1.6 KiB
JavaScript
54 lines
1.6 KiB
JavaScript
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"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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function encodeBufferToBase(buffer, base) {
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const encodeTable = baseEncodeTables[base];
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if(!encodeTable) throw new Error("Unknown encoding base" + base);
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const readLength = buffer.length;
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const Big = require("big.js");
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Big.RM = Big.DP = 0;
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let b = new Big(0);
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for(let i = readLength - 1; i >= 0; i--) {
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b = b.times(256).plus(buffer[i]);
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}
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let output = "";
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while(b.gt(0)) {
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output = encodeTable[b.mod(base)] + output;
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b = b.div(base);
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}
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Big.DP = 20;
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Big.RM = 1;
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return output;
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}
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function getHashDigest(buffer, hashType, digestType, maxLength) {
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hashType = hashType || "md5";
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maxLength = maxLength || 9999;
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const hash = require("crypto").createHash(hashType);
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hash.update(buffer);
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if(digestType === "base26" || digestType === "base32" || digestType === "base36" ||
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digestType === "base49" || digestType === "base52" || digestType === "base58" ||
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digestType === "base62" || digestType === "base64") {
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return encodeBufferToBase(hash.digest(), digestType.substr(4)).substr(0, maxLength);
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} else {
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return hash.digest(digestType || "hex").substr(0, maxLength);
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}
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}
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module.exports = getHashDigest;
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