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added logical shift operations #45

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added logical shift operations #45

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8f2dc8c
added lshift operations
0xflotus Oct 13, 2020
c63f43c
Update lshiftr.test.ts
0xflotus Oct 13, 2020
4521baa
Update lshiftl.ts
0xflotus Oct 13, 2020
55a55af
Update lshiftr.ts
0xflotus Oct 13, 2020
a6240ab
Update lshiftl.test.ts
0xflotus Oct 13, 2020
1643cf8
Update lshiftr.test.ts
0xflotus Oct 13, 2020
1dbe2f1
renamed files
0xflotus Oct 13, 2020
e3af71b
write directly to array
0xflotus Oct 13, 2020
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12 changes: 12 additions & 0 deletions source/bits/lshiftl.test.ts
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Original file line number Diff line number Diff line change
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import { Bits } from '../types'
import lshiftl from './lshiftl'

test('LSHIFTL', () => {
const bits1: Bits = [1, 0, 0, 0, 1, 1, 0, 1]
const expected1: Bits = [0, 0, 0, 1, 1, 0, 1, 0]
expect(lshiftl(bits1)).toEqual(expected1)

const bits2: Bits = [0, 0, 0, 1, 1, 1, 0, 0]
const expected2: Bits = [0, 0, 1, 1, 1, 0, 0, 0]
expect(lshiftl(bits2)).toEqual(expected2)
})
21 changes: 21 additions & 0 deletions source/bits/lshiftl.ts
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@@ -0,0 +1,21 @@
import { Bit, Bits } from '../types'

/**
* Logical Shift Left
*
* Shifts all given bits to left and returns the resulting bits
*
* @example
* lshiftl([1,0,1,1,0,1]) => [0,1,1,0,1,0]
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@0xflotus can you make a case for this not returning [1,0,1,1,0,1,0] instead? bitwise basically supports arbitrary size bit arrays, so perhaps this is an unexpected result

If you have a particular use-case in mind for the non-size-increasing version, we could also add a flag for this behavior.

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There are 6 Bits in the example and you are referring to 7 Bits. Which case should it return?

*
* @param {Array} bits input data
* @return {Array} [LSHIFTL bits]
*/
export default (bits: Bits): Bits => {
const result: Bits = []

for (let i: number = 0; i < bits.length - 1; i++) result.push(bits[i + 1])
result.push(<Bit>0)

return result
}
13 changes: 13 additions & 0 deletions source/bits/lshiftr.test.ts
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import { Bits } from '../types'
import lshiftr from './lshiftr'

test('LSHIFTR', () => {
const bits1: Bits = [1, 0, 0, 0, 1, 1, 0, 1]
const expected1: Bits = [0, 1, 0, 0, 0, 1, 1, 0]
expect(lshiftr(bits1)).toEqual(expected1)

const bits2: Bits = [0, 0, 0, 1, 1, 1, 0, 0]
const expected2: Bits = [0, 0, 0, 0, 1, 1, 1, 0]
expect(lshiftr(bits2)).toEqual(expected2)
})

21 changes: 21 additions & 0 deletions source/bits/lshiftr.ts
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Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
import { Bit, Bits } from '../types'

/**
* Logical Shift Right
*
* Shifts all given bits to right and returns the resulting bits
*
* @example
* lshiftr([1,0,1,1,0,1]) => [0,1,0,1,1,0]
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Not as concerned about this one, but I suppose it’s possible to argue that the leading 0 should be removed.

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are you sure?

*
* @param {Array} bits input data
* @return {Array} [LSHIFTR bits]
*/
export default (bits: Bits): Bits => {
const result: Bits = []

result.push(<Bit>0)
for (let i: number = 0; i < bits.length - 1; i++) result.push(bits[i])

return result
}