aaac7fed
 liuqimichale
add
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"use strict";
const baseEncodeTables = {
26: "abcdefghijklmnopqrstuvwxyz",
32: "123456789abcdefghjkmnpqrstuvwxyz", // no 0lio
36: "0123456789abcdefghijklmnopqrstuvwxyz",
49: "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ", // no lIO
52: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",
58: "123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ", // no 0lIO
62: "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",
64: "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_"
};
function encodeBufferToBase(buffer, base) {
const encodeTable = baseEncodeTables[base];
if(!encodeTable) throw new Error("Unknown encoding base" + base);
const readLength = buffer.length;
const Big = require("big.js");
Big.RM = Big.DP = 0;
let b = new Big(0);
for(let i = readLength - 1; i >= 0; i--) {
b = b.times(256).plus(buffer[i]);
}
let output = "";
while(b.gt(0)) {
output = encodeTable[b.mod(base)] + output;
b = b.div(base);
}
Big.DP = 20;
Big.RM = 1;
return output;
}
function getHashDigest(buffer, hashType, digestType, maxLength) {
hashType = hashType || "md5";
maxLength = maxLength || 9999;
const hash = require("crypto").createHash(hashType);
hash.update(buffer);
if(digestType === "base26" || digestType === "base32" || digestType === "base36" ||
digestType === "base49" || digestType === "base52" || digestType === "base58" ||
digestType === "base62" || digestType === "base64") {
return encodeBufferToBase(hash.digest(), digestType.substr(4)).substr(0, maxLength);
} else {
return hash.digest(digestType || "hex").substr(0, maxLength);
}
}
module.exports = getHashDigest;
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