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SR-10689: Fix bugs of DataProtocol's firstRange(of:in:)/lastRange(of:in:). #2499

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Merged
merged 2 commits into from
Jun 14, 2021
Merged

SR-10689: Fix bugs of DataProtocol's firstRange(of:in:)/lastRange(of:in:). #2499

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46ce38c
DataProtocol: Add tests for SR-10689.
YOCKOW Aug 31, 2019
ca8f3bd
DataProtocol: Reimplement firstRange(of:in:)/lastRange(of:in:) to fix…
YOCKOW Sep 1, 2019
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76 changes: 36 additions & 40 deletions Sources/Foundation/DataProtocol.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -136,60 +136,56 @@ extension DataProtocol {
return self.copyBytes(to: UnsafeMutableRawBufferPointer(start: ptr.baseAddress, count: ptr.count * MemoryLayout<DestinationType>.stride), from: range)
}

private func matches<D: DataProtocol>(_ data: D, from index: Index) -> Bool {
var haystackIndex = index
var needleIndex = data.startIndex

while true {
guard self[haystackIndex] == data[needleIndex] else { return false }

haystackIndex = self.index(after: haystackIndex)
needleIndex = data.index(after: needleIndex)
if needleIndex == data.endIndex {
// i.e. needle is found.
return true
} else if haystackIndex == endIndex {
return false
}
}
}

public func firstRange<D: DataProtocol, R: RangeExpression>(of data: D, in range: R) -> Range<Index>? where R.Bound == Index {
let r = range.relative(to: self)
let rangeCount = distance(from: r.lowerBound, to: r.upperBound)
if rangeCount < data.count {
let length = data.count

if length == 0 || length > distance(from: r.lowerBound, to: r.upperBound) {
return nil
}
var haystackIndex = r.lowerBound
let haystackEnd = index(r.upperBound, offsetBy: -data.count)
while haystackIndex < haystackEnd {
var compareIndex = haystackIndex
var needleIndex = data.startIndex
let needleEnd = data.endIndex
var matched = true
while compareIndex < haystackEnd && needleIndex < needleEnd {
if self[compareIndex] != data[needleIndex] {
matched = false
break
}
needleIndex = data.index(after: needleIndex)
compareIndex = index(after: compareIndex)
}
if matched {
return haystackIndex..<compareIndex

var position = r.lowerBound
while position < r.upperBound && distance(from: position, to: r.upperBound) >= length {
if matches(data, from: position) {
return position..<index(position, offsetBy: length)
}
haystackIndex = index(after: haystackIndex)
position = index(after: position)
}
return nil
}

public func lastRange<D: DataProtocol, R: RangeExpression>(of data: D, in range: R) -> Range<Index>? where R.Bound == Index {
let r = range.relative(to: self)
let rangeCount = distance(from: r.lowerBound, to: r.upperBound)
if rangeCount < data.count {
let length = data.count

if length == 0 || length > distance(from: r.lowerBound, to: r.upperBound) {
return nil
}
var haystackIndex = r.upperBound
let haystackStart = index(r.lowerBound, offsetBy: data.count)
while haystackIndex > haystackStart {
var compareIndex = haystackIndex
var needleIndex = data.endIndex
let needleStart = data.startIndex
var matched = true
while compareIndex > haystackStart && needleIndex > needleStart {
if self[compareIndex] != data[needleIndex] {
matched = false
break
}
needleIndex = data.index(before: needleIndex)
compareIndex = index(before: compareIndex)
}
if matched {
return compareIndex..<haystackIndex

var position = index(r.upperBound, offsetBy: -length)
while position >= r.lowerBound {
if matches(data, from: position) {
return position..<index(position, offsetBy: length)
}
haystackIndex = index(before: haystackIndex)
position = index(before: position)
}
return nil
}
Expand Down
92 changes: 92 additions & 0 deletions Tests/Foundation/Tests/TestNSData.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,7 @@ class TestNSData: LoopbackServerTest {
("test_base64DecodeWithPadding1", test_base64DecodeWithPadding1),
("test_base64DecodeWithPadding2", test_base64DecodeWithPadding2),
("test_rangeOfData", test_rangeOfData),
("test_sr10689_rangeOfDataProtocol", test_sr10689_rangeOfDataProtocol),
("test_initNSMutableData()", test_initNSMutableData),
("test_initNSMutableDataWithLength", test_initNSMutableDataWithLength),
("test_initNSMutableDataWithCapacity", test_initNSMutableDataWithCapacity),
Expand Down Expand Up @@ -848,6 +849,97 @@ class TestNSData: LoopbackServerTest {

}

func test_sr10689_rangeOfDataProtocol() {
// https://bugs.swift.org/browse/SR-10689

let base = Data([0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x02, 0x03,
0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x02, 0x03])
let subdata = base[10..<13] // [0x02, 0x03, 0x00]
let oneByte = base[14..<15] // [0x02]

do { // firstRange(of:in:)
func assertFirstRange(_ data: Data, _ fragment: Data, range: ClosedRange<Int>? = nil, expectedStartIndex: Int?,
message: @autoclosure () -> String = "", file: StaticString = #file, line: UInt = #line)
{
if let index = expectedStartIndex {
let expectedRange: Range<Int> = index..<(index + fragment.count)
if let someRange = range {
XCTAssertEqual(data.firstRange(of: fragment, in: someRange), expectedRange, message(), file: file, line: line)
} else {
XCTAssertEqual(data.firstRange(of: fragment), expectedRange, message(), file: file, line: line)
}
} else {
if let someRange = range {
XCTAssertNil(data.firstRange(of: fragment, in: someRange), message(), file: file, line: line)
} else {
XCTAssertNil(data.firstRange(of: fragment), message(), file: file, line: line)
}
}
}

assertFirstRange(base, base, expectedStartIndex: base.startIndex)
assertFirstRange(base, subdata, expectedStartIndex: 2)
assertFirstRange(base, oneByte, expectedStartIndex: 2)

assertFirstRange(subdata, base, expectedStartIndex: nil)
assertFirstRange(subdata, subdata, expectedStartIndex: subdata.startIndex)
assertFirstRange(subdata, oneByte, expectedStartIndex: subdata.startIndex)

assertFirstRange(oneByte, base, expectedStartIndex: nil)
assertFirstRange(oneByte, subdata, expectedStartIndex: nil)
assertFirstRange(oneByte, oneByte, expectedStartIndex: oneByte.startIndex)

assertFirstRange(base, subdata, range: 1...14, expectedStartIndex: 2)
assertFirstRange(base, subdata, range: 6...8, expectedStartIndex: 6)
assertFirstRange(base, subdata, range: 8...10, expectedStartIndex: nil)

assertFirstRange(base, oneByte, range: 1...14, expectedStartIndex: 2)
assertFirstRange(base, oneByte, range: 6...6, expectedStartIndex: 6)
assertFirstRange(base, oneByte, range: 8...9, expectedStartIndex: nil)
}

do { // lastRange(of:in:)
func assertLastRange(_ data: Data, _ fragment: Data, range: ClosedRange<Int>? = nil, expectedStartIndex: Int?,
message: @autoclosure () -> String = "", file: StaticString = #file, line: UInt = #line)
{
if let index = expectedStartIndex {
let expectedRange: Range<Int> = index..<(index + fragment.count)
if let someRange = range {
XCTAssertEqual(data.lastRange(of: fragment, in: someRange), expectedRange, message(), file: file, line: line)
} else {
XCTAssertEqual(data.lastRange(of: fragment), expectedRange, message(), file: file, line: line)
}
} else {
if let someRange = range {
XCTAssertNil(data.lastRange(of: fragment, in: someRange), message(), file: file, line: line)
} else {
XCTAssertNil(data.lastRange(of: fragment), message(), file: file, line: line)
}
}
}

assertLastRange(base, base, expectedStartIndex: base.startIndex)
assertLastRange(base, subdata, expectedStartIndex: 10)
assertLastRange(base, oneByte, expectedStartIndex: 14)

assertLastRange(subdata, base, expectedStartIndex: nil)
assertLastRange(subdata, subdata, expectedStartIndex: subdata.startIndex)
assertLastRange(subdata, oneByte, expectedStartIndex: subdata.startIndex)

assertLastRange(oneByte, base, expectedStartIndex: nil)
assertLastRange(oneByte, subdata, expectedStartIndex: nil)
assertLastRange(oneByte, oneByte, expectedStartIndex: oneByte.startIndex)

assertLastRange(base, subdata, range: 1...14, expectedStartIndex: 10)
assertLastRange(base, subdata, range: 6...8, expectedStartIndex: 6)
assertLastRange(base, subdata, range: 8...10, expectedStartIndex: nil)

assertLastRange(base, oneByte, range: 1...14, expectedStartIndex: 14)
assertLastRange(base, oneByte, range: 6...6, expectedStartIndex: 6)
assertLastRange(base, oneByte, range: 8...9, expectedStartIndex: nil)
}
}

// Check all of the NSMutableData constructors are available.
func test_initNSMutableData() {
let mData = NSMutableData()
Expand Down