2a09d1a4
 liuqimichale
添加宜春 天水 宣化
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
'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;
|
