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Merge pull request #161 from robtimp/swift3-all-your-base
All Your Base exercise
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,59 @@ | ||
| enum BaseError: ErrorProtocol { | ||
| case invalidInputBase | ||
| case invalidOutputBase | ||
| case negativeDigit | ||
| case invalidPositiveDigit | ||
| } | ||
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| struct Base { | ||
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| static func outputDigits(inputBase: Int, inputDigits: [Int], outputBase: Int) throws -> [Int] { | ||
| guard inputBase >= 2 else { | ||
| throw BaseError.invalidInputBase | ||
| } | ||
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| guard outputBase >= 2 else { | ||
| throw BaseError.invalidOutputBase | ||
| } | ||
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| let sum = try getSum(digits: inputDigits, base: inputBase) | ||
| let result = getDigits(sum: sum, base: outputBase) | ||
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| return result | ||
| } | ||
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| private static func getSum(digits: [Int], base: Int) throws -> Int { | ||
| var multiplier = 1 | ||
| var sum = 0 | ||
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| for digit in digits.reversed() { | ||
| guard digit >= 0 else { | ||
| throw BaseError.negativeDigit | ||
| } | ||
| guard digit < base else { | ||
| throw BaseError.invalidPositiveDigit | ||
| } | ||
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| sum += digit * multiplier | ||
| multiplier *= base | ||
| } | ||
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| return sum | ||
| } | ||
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| private static func getDigits(sum: Int, base: Int) -> [Int] { | ||
| var sum = sum | ||
| var digits = [Int]() | ||
| var multiplier = 1 | ||
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| while sum > 0 { | ||
| multiplier *= base | ||
| let value = sum % multiplier | ||
| let digit = value / (multiplier / base) | ||
| digits.append(digit) | ||
| sum -= value | ||
| } | ||
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| return digits.reversed() | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,103 @@ | ||
| #if swift(>=3.0) | ||
| import XCTest | ||
| #endif | ||
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| class AllYourBaseTest: XCTestCase { | ||
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| func errorThrown<T, U: ErrorProtocol>(byExpression expression: @autoclosure () throws -> T) -> U? { | ||
| do { | ||
| let _ = try expression() | ||
| return nil | ||
| } catch { | ||
| return error as? U | ||
| } | ||
| } | ||
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| func testSingleBitOneToDecimal() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 2, inputDigits: [1], outputBase: 10), [1]) | ||
| } | ||
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| func testBinaryToSingleDecimal() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 2, inputDigits: [1, 0, 1], outputBase: 10), [5]) | ||
| } | ||
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| func testSingleDecimalToBinary() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 10, inputDigits: [5], outputBase: 2), [1, 0, 1]) | ||
| } | ||
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| func testBinaryToMultipleDecimal() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 2, inputDigits: [1, 0, 1, 0, 1, 0], outputBase: 10), [4, 2]) | ||
| } | ||
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| func testDecimalToBinary() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 10, inputDigits: [4, 2], outputBase: 2), [1, 0, 1, 0, 1, 0]) | ||
| } | ||
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| func testTrinaryToHexadecimal() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 3, inputDigits: [1, 1, 2, 0], outputBase: 16), [2, 10]) | ||
| } | ||
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| func testHexadecimalToTrinary() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 16, inputDigits: [2, 10], outputBase: 3), [1, 1, 2, 0]) | ||
| } | ||
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| func test15BitInteger() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 97, inputDigits: [3, 46, 60], outputBase: 73), [6, 10, 45]) | ||
| } | ||
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| func testEmptyList() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 2, inputDigits: [], outputBase: 10), []) | ||
| } | ||
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| func testSingleZero() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 10, inputDigits: [0], outputBase: 2), []) | ||
| } | ||
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| func testMultipleZeros() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 10, inputDigits: [0, 0, 0], outputBase: 2), []) | ||
| } | ||
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| func testLeadingZeros() { | ||
| XCTAssertEqual(try! Base.outputDigits(inputBase: 7, inputDigits: [0, 6, 0], outputBase: 10), [4, 2]) | ||
| } | ||
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| func testNegativeDigit() { | ||
| let error: BaseError? = errorThrown(byExpression: try Base.outputDigits(inputBase: 2, inputDigits: [1, -1, 1, 0, 1, 0], outputBase: 10)) | ||
| XCTAssertTrue(error == .negativeDigit) | ||
| } | ||
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| func testInvalidPositiveDigit() { | ||
| let error: BaseError? = errorThrown(byExpression: try Base.outputDigits(inputBase: 2, inputDigits: [1, 2, 1, 0, 1, 0], outputBase: 10)) | ||
| XCTAssertTrue(error == .invalidPositiveDigit) | ||
| } | ||
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| func testFirstBaseIsOne() { | ||
| let error: BaseError? = errorThrown(byExpression: try Base.outputDigits(inputBase: 1, inputDigits: [], outputBase: 10)) | ||
| XCTAssertTrue(error == .invalidInputBase) | ||
| } | ||
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| func testSecondBaseIsOne() { | ||
| let error: BaseError? = errorThrown(byExpression: try Base.outputDigits(inputBase: 2, inputDigits: [1, 0, 1, 0, 1, 0], outputBase: 1)) | ||
| XCTAssertTrue(error == .invalidOutputBase) | ||
| } | ||
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| func testFirstBaseIsZero() { | ||
| let error: BaseError? = errorThrown(byExpression: try Base.outputDigits(inputBase: 0, inputDigits: [], outputBase: 10)) | ||
| XCTAssertTrue(error == .invalidInputBase) | ||
| } | ||
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| func testSecondBaseIsZero() { | ||
| let error: BaseError? = errorThrown(byExpression: try Base.outputDigits(inputBase: 10, inputDigits: [7], outputBase: 0)) | ||
| XCTAssertTrue(error == .invalidOutputBase) | ||
| } | ||
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| func testFirstBaseIsNegative() { | ||
| let error: BaseError? = errorThrown(byExpression: try Base.outputDigits(inputBase: -2, inputDigits: [1], outputBase: 10)) | ||
| XCTAssertTrue(error == .invalidInputBase) | ||
| } | ||
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| func testSecondBaseIsNegative() { | ||
| let error: BaseError? = errorThrown(byExpression: try Base.outputDigits(inputBase: 2, inputDigits: [1], outputBase: -7)) | ||
| XCTAssertTrue(error == .invalidOutputBase) | ||
| } | ||
| } |
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