base32.js ➔ decode - Code Metrics - Inspection of "Make cashaddress package the default" - btccom/cashaddress-js - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Pull Request — master (#3)

by thomas

created 2018-01-04 19:24 UTC

base32.js ➔ decode C

↳ Parent: src/base32.js

Complexity

Conditions	12
Paths	3

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	32
CRAP Score	12

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	12
c	1
b	0
f	0
nc	3
nop	1
dl	0
loc	55
ccs	32
cts	32
cp	1
crap	12
rs	6.8009

How to fix Long Method Complexity

'use strict'
let BigInteger = require('bigi')
let ALPHABET = 'qpzry9x8gf2tvdw0s3jn54khce6mua7l'

// pre-compute lookup table
let SEPARATOR = ':'
let CSLEN = 8
let ALPHABET_MAP = {}
for (let z = 0; z < ALPHABET.length; z++) {
    let x = ALPHABET.charAt(z)
    if (ALPHABET_MAP[x] !== undefined) {
        throw new TypeError(x + ' is ambiguous')
    }
    ALPHABET_MAP[x] = z
}

function polymodStep (pre) {
    let b = pre.shiftRight(35)
    let mask = BigInteger.fromHex('07ffffffff')

    let v = pre.and(mask).shiftLeft(new BigInteger('5'))

    if (b.and(new BigInteger('1')).intValue() > 0) {
        v = v.xor(BigInteger.fromHex('98f2bc8e61'))
    }
    if (b.and(new BigInteger('2')).intValue()) {
        v = v.xor(BigInteger.fromHex('79b76d99e2'))
    }
    if (b.and(new BigInteger('4')).intValue()) {
        v = v.xor(BigInteger.fromHex('f33e5fb3c4'))
    }
    if (b.and(new BigInteger('8')).intValue()) {
        v = v.xor(BigInteger.fromHex('ae2eabe2a8'))
    }
    if (b.and(new BigInteger('16')).intValue()) {
        v = v.xor(BigInteger.fromHex('1e4f43e470'))
    }

    return v
}

function prefixChk (prefix) {
    let chk = new BigInteger('1')
    for (let i = 0; i < prefix.length; ++i) {
        let c = prefix.charCodeAt(i)

        let mixwith = new BigInteger('' + (c & 0x1f))
        chk = polymodStep(chk).xor(mixwith)
    }

    chk = polymodStep(chk)
    return chk
}

function encode (prefix, words) {
    // too long?
    if ((prefix.length + CSLEN + 1 + words.length) > 90) {
        throw new TypeError('Exceeds Base32 maximum length')
    }

    prefix = prefix.toLowerCase()

    // determine chk mod
    let chk = prefixChk(prefix)
    let result = prefix + SEPARATOR
    for (let i = 0; i < words.length; ++i) {
        let x = words[i]
        if ((x >>> 5) !== 0) {
            throw new Error('Non 5-bit word')
        }

        chk = polymodStep(chk).xor(new BigInteger('' + x))
        result += ALPHABET.charAt(x)
    }

    for (let i = 0; i < CSLEN; ++i) {
        chk = polymodStep(chk)
    }
    chk = chk.xor(new BigInteger('1'))
    for (let i = 0; i < CSLEN; ++i) {
        let pos = 5 * (CSLEN - 1 - i)
        let v2 = chk.shiftRight(new BigInteger('' + pos)).and(BigInteger.fromHex('1f'))
        result += ALPHABET.charAt(v2.toString(10))
    }

    return result
}

function decode (str) {
    if (str.length < 8) {
        throw new TypeError(str + ' too short')
    }
    if (str.length > 90) {
        throw new TypeError(str + ' too long')
    }

    // don't allow mixed case
    let lowered = str.toLowerCase()
    let uppered = str.toUpperCase()
    if (str !== lowered && str !== uppered) {
        throw new Error('Mixed-case string ' + str)
    }

    str = lowered

    let split = str.lastIndexOf(SEPARATOR)
    if (split === -1) {
        throw new Error('No separator character for ' + str)
    }

    if (split === 0) {
        throw new Error('Missing prefix for ' + str)
    }

    let prefix = str.slice(0, split)
    let wordChars = str.slice(split + 1)
    if (wordChars.length < 6) {
        throw new Error('Data too short')
    }

    let chk = prefixChk(prefix)
    let words = []
    for (let i = 0; i < wordChars.length; ++i) {
        let c = wordChars.charAt(i)
        let v = ALPHABET_MAP[c]
        if (v === undefined) {
            throw new Error('Unknown character ' + c)
        }

        chk = polymodStep(chk).xor(new BigInteger('' + v))
        // not in the checksum?
        if (i + CSLEN >= wordChars.length) {
            continue
        }
        words.push(v)
    }

    if (chk.toString(10) !== '1') {
        throw new Error('Invalid checksum for ' + str)
    }

    return { prefix, words }
}

function convert (data, inBits, outBits, pad) {
    let value = 0
    let bits = 0
    let maxV = (1 << outBits) - 1

    let result = []
    for (let i = 0; i < data.length; ++i) {
        value = (value << inBits) | data[i]
        bits += inBits

        while (bits >= outBits) {
            bits -= outBits
            result.push((value >>> bits) & maxV)
        }
    }

    if (pad) {
        if (bits > 0) {
            result.push((value << (outBits - bits)) & maxV)
        }
    } else {
        if (bits >= inBits) {
            throw new Error('Excess padding')
        }
        if ((value << (outBits - bits)) & maxV) {

            throw new Error('Non-zero padding')
        }
    }

    return result
}

function toWords (bytes) {
    return convert(bytes, 8, 5, true)
}

function fromWords (words) {
    return convert(words, 5, 8, false)
}

module.exports = { decode, encode, toWords, fromWords }


1		'use strict'
2	1	let BigInteger = require('bigi')
3	1	let ALPHABET = 'qpzry9x8gf2tvdw0s3jn54khce6mua7l'
4
5		// pre-compute lookup table
6	1	let SEPARATOR = ':'
7	1	let CSLEN = 8
8	1	let ALPHABET_MAP = {}
9	1	for (let z = 0; z < ALPHABET.length; z++) {
10	32	let x = ALPHABET.charAt(z)
11	32	if (ALPHABET_MAP[x] !== undefined) {
12		throw new TypeError(x + ' is ambiguous')
13		}
14	32	ALPHABET_MAP[x] = z
15		}
16
17		function polymodStep (pre) {
18	2432	let b = pre.shiftRight(35)
19	2432	let mask = BigInteger.fromHex('07ffffffff')
20
21	2432	let v = pre.and(mask).shiftLeft(new BigInteger('5'))
22
23	2432	if (b.and(new BigInteger('1')).intValue() > 0) {
24	1080	v = v.xor(BigInteger.fromHex('98f2bc8e61'))
25		}
26	2432	if (b.and(new BigInteger('2')).intValue()) {
27	1033	v = v.xor(BigInteger.fromHex('79b76d99e2'))
28		}
29	2432	if (b.and(new BigInteger('4')).intValue()) {
30	1030	v = v.xor(BigInteger.fromHex('f33e5fb3c4'))
31		}
32	2432	if (b.and(new BigInteger('8')).intValue()) {
33	1141	v = v.xor(BigInteger.fromHex('ae2eabe2a8'))
34		}
35	2432	if (b.and(new BigInteger('16')).intValue()) {
36	1123	v = v.xor(BigInteger.fromHex('1e4f43e470'))
37		}
38
39	2432	return v
40		}
41
42		function prefixChk (prefix) {
43	48	let chk = new BigInteger('1')
44	48	for (let i = 0; i < prefix.length; ++i) {
45	483	let c = prefix.charCodeAt(i)
46
47	483	let mixwith = new BigInteger('' + (c & 0x1f))
48	483	chk = polymodStep(chk).xor(mixwith)
49		}
50
51	48	chk = polymodStep(chk)
52	48	return chk
53		}
54
55		function encode (prefix, words) {
56		// too long?
57	18	if ((prefix.length + CSLEN + 1 + words.length) > 90) {
58	1	throw new TypeError('Exceeds Base32 maximum length')
59		}
60
61	17	prefix = prefix.toLowerCase()
62
63		// determine chk mod
64	17	let chk = prefixChk(prefix)
65	17	let result = prefix + SEPARATOR
66	17	for (let i = 0; i < words.length; ++i) {
67	547	let x = words[i]
68	547	if ((x >>> 5) !== 0) {
69	1	throw new Error('Non 5-bit word')
70		}
71
72	546	chk = polymodStep(chk).xor(new BigInteger('' + x))
73	546	result += ALPHABET.charAt(x)
74		}
75
76	16	for (let i = 0; i < CSLEN; ++i) {
77	128	chk = polymodStep(chk)
78		}
79	16	chk = chk.xor(new BigInteger('1'))
80	16	for (let i = 0; i < CSLEN; ++i) {
81	128	let pos = 5 * (CSLEN - 1 - i)
82	128	let v2 = chk.shiftRight(new BigInteger('' + pos)).and(BigInteger.fromHex('1f'))
83	128	result += ALPHABET.charAt(v2.toString(10))
84		}
85
86	16	return result
87		}
88
89		function decode (str) {
90	37	if (str.length < 8) {
91	1	throw new TypeError(str + ' too short')
92		}
93	36	if (str.length > 90) {
94	1	throw new TypeError(str + ' too long')
95		}
96
97		// don't allow mixed case
98	35	let lowered = str.toLowerCase()
99	35	let uppered = str.toUpperCase()
100	35	if (str !== lowered && str !== uppered) {
101	1	throw new Error('Mixed-case string ' + str)
102		}
103
104	34	str = lowered
105
106	34	let split = str.lastIndexOf(SEPARATOR)
107	34	if (split === -1) {
108	1	throw new Error('No separator character for ' + str)
109		}
110
111	33	if (split === 0) {
112	1	throw new Error('Missing prefix for ' + str)
113		}
114
115	32	let prefix = str.slice(0, split)
116	32	let wordChars = str.slice(split + 1)
117	32	if (wordChars.length < 6) {
118	1	throw new Error('Data too short')
119		}
120
121	31	let chk = prefixChk(prefix)
122	31	let words = []
123	31	for (let i = 0; i < wordChars.length; ++i) {
124	1228	let c = wordChars.charAt(i)
125	1228	let v = ALPHABET_MAP[c]
126	1228	if (v === undefined) {
127	1	throw new Error('Unknown character ' + c)
128		}
129
130	1227	chk = polymodStep(chk).xor(new BigInteger('' + v))
131		// not in the checksum?
132	1227	if (i + CSLEN >= wordChars.length) {
133	240	continue
134		}
135	987	words.push(v)
136		}
137
138	30	if (chk.toString(10) !== '1') {
139	9	throw new Error('Invalid checksum for ' + str)
140		}
141
142	21	return { prefix, words }
143		}
144
145		function convert (data, inBits, outBits, pad) {
146	39	let value = 0
147	39	let bits = 0
148	39	let maxV = (1 << outBits) - 1
149
150	39	let result = []
151	39	for (let i = 0; i < data.length; ++i) {
152	1058	value = (value << inBits) \| data[i]
153	1058	bits += inBits
154
155	1058	while (bits >= outBits) {
156	973	bits -= outBits
157	973	result.push((value >>> bits) & maxV)
158		}
159		}
160
161	39	if (pad) {
162	16	if (bits > 0) {
163	16	result.push((value << (outBits - bits)) & maxV)
164		}
165		} else {
166	23	if (bits >= inBits) {
167	1	throw new Error('Excess padding')
168		}
169	22	if ((value << (outBits - bits)) & maxV) {
		0 ignored issues – show introduced 2018-01-03 13:57 UTC by Report Bug Copy Issue Report You have used a bitwise operator `&` in a condition. Did you maybe want to use the logical operator `&&` Loading history...
170	1	throw new Error('Non-zero padding')
171		}
172		}
173
174	37	return result
175		}
176
177		function toWords (bytes) {
178	16	return convert(bytes, 8, 5, true)
179		}
180
181		function fromWords (words) {
182	23	return convert(words, 5, 8, false)
183		}
184
185		module.exports = { decode, encode, toWords, fromWords }
186

btccom / cashaddress-js

Pull Request — master (#3)

base32.js ➔ decode C

Complexity

Size

Duplication

Code Coverage

Importance

How to fix Long Method Complexity

Long Method

Complexity

Duplication Side-by-Side

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