SwiftCryptoTokenFormatter

Formatter for crypto token amounts.

Rules

• Cut off after the 5th decimal, no matter how many decimals there are: 0.12345
• Remove trailing zeroes, i.e. display 0.10000 as 0.1
• Use the 5 decimals up until 999.99999
• Display '< 0.00001' for values less than 0.00001
• Use 1 decimal less from 1,000.0001 until 9,999.9999
• Use 1 decimal less from 10,000.001 until 99,999.999
• Use 1 decimal less from 100,000.01 until 999,999.99
• Use 1 decimal less from 1,000,000.1 until 9,999,999.9
• From 10,000,000 No Decimals until 99,999,999
• Then Use 10.001M until 999.999M
• Then 1.001B until 999.999B
• Then 1.001T until 999.999T
• Then just > 999T
• Thousands and decimal separators are used according to user's locale.
• M, B, T is localized

import SwiftCryptoTokenFormatter
import BigInt

let f = TokenFormatter()
f.string(from: BigDecimal(100_000_000_000000000, 9)) // 100M
f.string(from: BigDecimal(BigInt("999999999000000000000"), 9)) // 999.999B

Features

Custom rounding behaviour

f.roundingBehavior = .cutoff
f.string(from: BigDecimal(0_0000101, 7)) // 0.00001
f.roundingBehavior = .roundUp
f.string(from: BigDecimal(0_0000101, 7)) // 0.00002

Support of negative numbers

f.string(from: BigDecimal(-10_000_001000000, 9) // -10,000.001

Number from string

f.number(from: "0,001", precision: 3) == BigDecimal(1, 3)

Localizatoin

string(from:) allows to override default decimalSeparator, thousandSeparator and literals.

localizedString(from:) uses:

• Locale.autoupdatingCurrent for decimalSeparator and thousandSeparator
• "amount_millions", "amount_billions" and "amount_trillions" localized strings from literals. You need to provide localizable strings for different locales.

// Assuming russian locale and "amount_billions" = "Б"
formatter.localizedString(from: BigDecimal(BigInt("999999999000000000000"), 9)) // 999,999Б

Installation

Prerequisites

• iOS 11.0 or macOS 10.14
• Xcode 10.3
• Swift 5

Manual

Add this repository as a submodule:

git submodule add https://github.com/gnosis/SwiftCryptoTokenFormatter.git

Fetch the dependencies

cd SwiftCryptoTokenFormatter
git submodule update --init

Dependencies of the SwiftCryptoTokenFormatter library:

• BigInt

Drag and drop the SwiftCryptoTokenFormatter.xcodeproj into your project and link the SwiftCryptoTokenFormatter static library.

CocoaPods

pod 'SwiftCryptoTokenFormatter'

Carthage

In your Cartfile: github "gnosis/SwiftCryptoTokenFormatter"

Run carthage update to build the framework and drag the SwiftCryptoTokenFormatter.framework into your Xcode project.

Swift Package Manager

You can use Swift Package Manager and add dependency in your Package.swift:

    dependencies: [
        .package(url: "https://github.com/gnosis/SwiftCryptoTokenFormatter.git", .upToNextMinor(from: "1.0.0"))
    ]

Contributors

• Dmitry Bespalov (DmitryBespalov)
• Andrey Scherbovich (sche)

License

MIT License (see the LICENSE file).