'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;
|
