76 lines
1.8 KiB
TypeScript
76 lines
1.8 KiB
TypeScript
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import bigInt, { BigInteger } from 'big-integer'
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import { randomBytes } from './buffer-utils'
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export const bigIntTwo = bigInt(2)
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export const LONG_OVERFLOW = bigInt('8000000000000000', 16)
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export const LONG_SIGN_DELTA = bigInt('10000000000000000', 16)
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export function ulongToLong(val: BigInteger): BigInteger {
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if (val.gt(LONG_OVERFLOW)) return val.minus(LONG_SIGN_DELTA)
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return val
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}
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export function longToUlong(val: BigInteger): BigInteger {
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if (val.isNegative()) return val.plus(LONG_SIGN_DELTA)
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return val
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}
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export function writeBigInt(
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buffer: Buffer,
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value: BigInteger,
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length = 0,
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offset = 0,
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le = false
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): void {
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const array = value.toArray(256).value
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if (length !== 0 && array.length > length)
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throw new Error('Value out of bounds')
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if (length !== 0) {
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// padding
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while (array.length !== length) array.unshift(0)
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}
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if (le) array.reverse()
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buffer.set(array, offset)
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}
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export function bigIntToBuffer(
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value: BigInteger,
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length = 0,
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le = false
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): Buffer {
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const array = value.toArray(256).value
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if (length !== 0 && array.length > length)
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throw new Error('Value out of bounds')
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if (length !== 0) {
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// padding
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while (array.length !== length) array.unshift(0)
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}
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if (le) array.reverse()
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const buffer = Buffer.alloc(length || array.length)
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buffer.set(array, 0)
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return buffer
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}
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export function bufferToBigInt(
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buffer: Buffer,
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offset = 0,
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length = buffer.length,
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le = false
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): BigInteger {
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const arr = [...buffer.slice(offset, offset + length)]
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if (le) arr.reverse()
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return bigInt.fromArray(arr, 256)
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}
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export function randomBigInt(size: number): BigInteger {
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return bufferToBigInt(randomBytes(size))
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}
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