mtcute/packages/core/tests/buffer-utils.spec.ts

import { describe, it } from 'mocha'
import { expect } from 'chai'
import {
    buffersEqual,
    cloneBuffer,
    encodeUrlSafeBase64,
    isProbablyPlainText,
    parseUrlSafeBase64,
    randomBytes,
    reverseBuffer,
    telegramRleDecode,
    telegramRleEncode,
    xorBuffer,
    xorBufferInPlace,
} from '../src/utils/buffer-utils'

describe('reverseBuffer', () => {
    it('should reverse even-sized buffers', () => {
        const buf = Buffer.from([1, 2, 3, 4])
        reverseBuffer(buf)
        expect([...buf]).to.eql([4, 3, 2, 1])
    })

    it('should reverse odd-sized buffers', () => {
        const buf = Buffer.from([1, 2, 3])
        reverseBuffer(buf)
        expect([...buf]).to.eql([3, 2, 1])
    })
})

describe('buffersEqual', () => {
    it('should return true for equal buffers', () => {
        expect(buffersEqual(Buffer.from([]), Buffer.from([]))).is.true
        expect(buffersEqual(Buffer.from([1, 2, 3]), Buffer.from([1, 2, 3]))).is
            .true
    })

    it('should return false for non-equal buffers', () => {
        expect(buffersEqual(Buffer.from([1]), Buffer.from([]))).is.false
        expect(buffersEqual(Buffer.from([1, 2, 3]), Buffer.from([1, 2, 4]))).is
            .false
    })
})

describe('xorBuffer', () => {
    it('should xor buffers without modifying original', () => {
        const data = Buffer.from('hello')
        const key = Buffer.from('xor')

        const xored = xorBuffer(data, key)
        expect(data.toString()).eq('hello')
        expect(key.toString()).eq('xor')
        expect(xored.toString('hex')).eq('100a1e6c6f')
    })

    it('should be deterministic', () => {
        const data = Buffer.from('hello')
        const key = Buffer.from('xor')

        const xored1 = xorBuffer(data, key)
        expect(xored1.toString('hex')).eq('100a1e6c6f')

        const xored2 = xorBuffer(data, key)
        expect(xored2.toString('hex')).eq('100a1e6c6f')
    })

    it('second call should decode content', () => {
        const data = Buffer.from('hello')
        const key = Buffer.from('xor')

        const xored1 = xorBuffer(data, key)
        expect(xored1.toString('hex')).eq('100a1e6c6f')

        const xored2 = xorBuffer(xored1, key)
        expect(xored2.toString()).eq('hello')
    })
})

describe('xorBufferInPlace', () => {
    it('should xor buffers by modifying original', () => {
        const data = Buffer.from('hello')
        const key = Buffer.from('xor')

        xorBufferInPlace(data, key)
        expect(data.toString('hex')).eq('100a1e6c6f')
        expect(key.toString()).eq('xor')
    })

    it('second call should decode content', () => {
        const data = Buffer.from('hello')
        const key = Buffer.from('xor')

        xorBufferInPlace(data, key)
        expect(data.toString('hex')).eq('100a1e6c6f')

        xorBufferInPlace(data, key)
        expect(data.toString()).eq('hello')
    })
})

describe('randomBytes', () => {
    it('should return exactly N bytes', () => {
        expect(randomBytes(0).length).eq(0)
        expect(randomBytes(5).length).eq(5)
        expect(randomBytes(10).length).eq(10)
        expect(randomBytes(256).length).eq(256)
    })

    it('should not be deterministic', () => {
        expect([...randomBytes(8)]).not.eql([...randomBytes(8)])
    })
})

describe('cloneBuffer', () => {
    it('should clone buffer', () => {
        const orig = Buffer.from([1, 2, 3])
        const copy = cloneBuffer(orig)

        expect([...copy]).eql([1, 2, 3])
        orig[0] = 0xff
        expect(copy[0]).not.eql(0xff)
    })

    it('should clone buffer partially', () => {
        const orig = Buffer.from([1, 2, 3, 4, 5])
        const copy = cloneBuffer(orig, 1, 4)

        expect([...copy]).eql([2, 3, 4])
        orig[0] = 0xff
        expect(copy[0]).not.eql(0xff)
    })
})

describe('parseUrlSafeBase64', () => {
    it('should parse url-safe base64', () => {
        expect(parseUrlSafeBase64('qu7d8aGTeuF6-g').toString('hex')).eq(
            'aaeeddf1a1937ae17afa'
        )
    })
    it('should parse normal base64', () => {
        expect(parseUrlSafeBase64('qu7d8aGTeuF6+g==').toString('hex')).eq(
            'aaeeddf1a1937ae17afa'
        )
    })
})

describe('encodeUrlSafeBase64', () => {
    it('should encode to url-safe base64', () => {
        expect(
            encodeUrlSafeBase64(Buffer.from('aaeeddf1a1937ae17afa', 'hex'))
        ).eq('qu7d8aGTeuF6-g')
    })
})

describe('telegramRleEncode', () => {
    it('should not modify input if there are no \\x00', () => {
        expect(
            telegramRleEncode(Buffer.from('aaeeff', 'hex')).toString('hex')
        ).eq('aaeeff')
    })

    it('should collapse consecutive \\x00', () => {
        expect(
            telegramRleEncode(Buffer.from('00000000aa', 'hex')).toString('hex')
        ).eq('0004aa')
        expect(
            telegramRleEncode(
                Buffer.from('00000000aa000000aa', 'hex')
            ).toString('hex')
        ).eq('0004aa0003aa')
        expect(
            telegramRleEncode(Buffer.from('00000000aa0000', 'hex')).toString(
                'hex'
            )
        ).eq('0004aa0002')
        expect(
            telegramRleEncode(Buffer.from('00aa00', 'hex')).toString('hex')
        ).eq('0001aa0001')
    })
})

describe('telegramRleDecode', () => {
    it('should not mofify input if there are no \\x00', () => {
        expect(
            telegramRleDecode(Buffer.from('aaeeff', 'hex')).toString('hex')
        ).eq('aaeeff')
    })

    it('should expand two-byte sequences starting with \\x00', () => {
        expect(
            telegramRleDecode(Buffer.from('0004aa', 'hex')).toString('hex')
        ).eq('00000000aa')
        expect(
            telegramRleDecode(Buffer.from('0004aa0000', 'hex')).toString('hex')
        ).eq('00000000aa')
        expect(
            telegramRleDecode(Buffer.from('0004aa0003aa', 'hex')).toString(
                'hex'
            )
        ).eq('00000000aa000000aa')
        expect(
            telegramRleDecode(Buffer.from('0004aa0002', 'hex')).toString('hex')
        ).eq('00000000aa0000')
        expect(
            telegramRleDecode(Buffer.from('0001aa0001', 'hex')).toString('hex')
        ).eq('00aa00')
    })
})

describe('isProbablyPlainText', () => {
    it('should return true for buffers only containing printable ascii', () => {
        expect(
            isProbablyPlainText(Buffer.from('hello this is some ascii text'))
        ).to.be.true
        expect(
            isProbablyPlainText(
                Buffer.from(
                    'hello this is some ascii text\nwith unix new lines'
                )
            )
        ).to.be.true
        expect(
            isProbablyPlainText(
                Buffer.from(
                    'hello this is some ascii text\r\nwith windows new lines'
                )
            )
        ).to.be.true
        expect(
            isProbablyPlainText(
                Buffer.from(
                    'hello this is some ascii text\n\twith unix new lines and tabs'
                )
            )
        ).to.be.true
        expect(
            isProbablyPlainText(
                Buffer.from(
                    'hello this is some ascii text\r\n\twith windows new lines and tabs'
                )
            )
        ).to.be.true
    })

    it('should return false for buffers containing some binary data', () => {
        expect(isProbablyPlainText(Buffer.from('hello this is cedilla: ç'))).to
            .be.false
        expect(
            isProbablyPlainText(
                Buffer.from('hello this is some ascii text with emojis 🌸')
            )
        ).to.be.false

        // random strings of 16 bytes
        expect(
            isProbablyPlainText(
                Buffer.from('717f80f08eb9d88c3931712c0e2be32f', 'hex')
            )
        ).to.be.false
        expect(
            isProbablyPlainText(
                Buffer.from('20e8e218e54254c813b261432b0330d7', 'hex')
            )
        ).to.be.false
    })
})