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Make ArbitraryBase Unicode-aware (#1299)

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* Make ArbitraryBase Unicode-aware

https://mathiasbynens.be/notes/javascript-unicode#counting-symbols

* Fix performance bug and add Unicode test

* Add BigInt version and push output chars to array
This commit is contained in:
lionel-rowe
2023-02-23 22:34:47 +08:00
committed by GitHub
parent 6aa3314b93
commit 0c427580f1
2 changed files with 89 additions and 20 deletions
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87
Conversions/ArbitraryBase.js
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@ -1,20 +1,36 @@
/**
* Converts a string from one base to other
* Divide two numbers and get the result of floor division and remainder
* @param {number} dividend
* @param {number} divisor
* @returns {[result: number, remainder: number]}
*/
const floorDiv = (dividend, divisor) => {
const remainder = dividend % divisor
const result = Math.floor(dividend / divisor)
return [result, remainder]
}
/**
* Converts a string from one base to other. Loses accuracy above the value of `Number.MAX_SAFE_INTEGER`.
* @param {string} stringInBaseOne String in input base
* @param {string} baseOneCharacters Character set for the input base
* @param {string} baseTwoCharacters Character set for the output base
* @returns {string}
*/
const convertArbitraryBase = (stringInBaseOne, baseOneCharacters, baseTwoCharacters) => {
if ([stringInBaseOne, baseOneCharacters, baseTwoCharacters].map(arg => typeof arg).some(type => type !== 'string')) {
const convertArbitraryBase = (stringInBaseOne, baseOneCharacterString, baseTwoCharacterString) => {
if ([stringInBaseOne, baseOneCharacterString, baseTwoCharacterString].map(arg => typeof arg).some(type => type !== 'string')) {
throw new TypeError('Only string arguments are allowed')
}
[baseOneCharacters, baseTwoCharacters].forEach(baseString => {
const charactersInBase = [...baseString]
const baseOneCharacters = [...baseOneCharacterString]
const baseTwoCharacters = [...baseTwoCharacterString]
for (const charactersInBase of [baseOneCharacters, baseTwoCharacters]) {
if (charactersInBase.length !== new Set(charactersInBase).size) {
throw new TypeError('Duplicate characters in character set are not allowed')
}
})
}
const reversedStringOneChars = [...stringInBaseOne].reverse()
const stringOneBase = baseOneCharacters.length
let value = 0
@ -27,24 +43,57 @@ const convertArbitraryBase = (stringInBaseOne, baseOneCharacters, baseTwoCharact
value += (digitNumber * placeValue)
placeValue *= stringOneBase
}
let stringInBaseTwo = ''
const outputChars = []
const stringTwoBase = baseTwoCharacters.length
while (value > 0) {
const remainder = value % stringTwoBase
stringInBaseTwo = baseTwoCharacters.charAt(remainder) + stringInBaseTwo
value /= stringTwoBase
const [divisionResult, remainder] = floorDiv(value, stringTwoBase)
outputChars.push(baseTwoCharacters[remainder])
value = divisionResult
}
const baseTwoZero = baseTwoCharacters.charAt(0)
return stringInBaseTwo.replace(new RegExp(`^${baseTwoZero}+`), '')
return outputChars.reverse().join('') || baseTwoCharacters[0]
}
export { convertArbitraryBase }
/**
* Converts a arbitrary-length string from one base to other. Doesn't lose accuracy.
* @param {string} stringInBaseOne String in input base
* @param {string} baseOneCharacters Character set for the input base
* @param {string} baseTwoCharacters Character set for the output base
* @returns {string}
*/
const convertArbitraryBaseBigIntVersion = (stringInBaseOne, baseOneCharacterString, baseTwoCharacterString) => {
if ([stringInBaseOne, baseOneCharacterString, baseTwoCharacterString].map(arg => typeof arg).some(type => type !== 'string')) {
throw new TypeError('Only string arguments are allowed')
}
// > convertArbitraryBase('98', '0123456789', '01234567')
// '142'
const baseOneCharacters = [...baseOneCharacterString]
const baseTwoCharacters = [...baseTwoCharacterString]
// > convertArbitraryBase('98', '0123456789', 'abcdefgh')
// 'bec'
for (const charactersInBase of [baseOneCharacters, baseTwoCharacters]) {
if (charactersInBase.length !== new Set(charactersInBase).size) {
throw new TypeError('Duplicate characters in character set are not allowed')
}
}
const reversedStringOneChars = [...stringInBaseOne].reverse()
const stringOneBase = BigInt(baseOneCharacters.length)
let value = 0n
let placeValue = 1n
for (const digit of reversedStringOneChars) {
const digitNumber = BigInt(baseOneCharacters.indexOf(digit))
if (digitNumber === -1n) {
throw new TypeError(`Not a valid character: ${digit}`)
}
value += (digitNumber * placeValue)
placeValue *= stringOneBase
}
const outputChars = []
const stringTwoBase = BigInt(baseTwoCharacters.length)
while (value > 0n) {
const divisionResult = value / stringTwoBase
const remainder = value % stringTwoBase
outputChars.push(baseTwoCharacters[remainder])
value = divisionResult
}
return outputChars.reverse().join('') || baseTwoCharacters[0]
}
// > convertArbitraryBase('129', '0123456789', '01234567')
// '201'
export { convertArbitraryBase, convertArbitraryBaseBigIntVersion }