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guidedwaysguidedways
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zero-copy optimizations
1 parent 772b3f5 commit b2f884c

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Lines changed: 656 additions & 28 deletions

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‎.swiftpm/xcode/xcshareddata/xcbaselines/SwiftJSONSanitizerTests.xcbaseline/965DC438-BAFD-43E1-B19E-60D59BA42289.plist‎

Lines changed: 31 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,12 +6,42 @@
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<dict>
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<key>SwiftJSONSanitizerTests</key>
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<dict>
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<key>testDeeplyNestedJSONPerformance()</key>
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<dict>
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<key>com.apple.XCTPerformanceMetric_WallClockTime</key>
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<dict>
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<key>baselineAverage</key>
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<real>0.000559</real>
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<key>baselineIntegrationDisplayName</key>
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<string>Local Baseline</string>
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</dict>
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</dict>
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<key>testLargeArrayPerformance()</key>
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<dict>
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<key>com.apple.XCTPerformanceMetric_WallClockTime</key>
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<dict>
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<key>baselineAverage</key>
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<real>0.066844</real>
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<key>baselineIntegrationDisplayName</key>
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<string>Local Baseline</string>
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</dict>
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</dict>
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<key>testLargeJSONPerformance()</key>
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<dict>
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<key>com.apple.XCTPerformanceMetric_WallClockTime</key>
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<dict>
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<key>baselineAverage</key>
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<real>0.620000</real>
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<real>0.915770</real>
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<key>baselineIntegrationDisplayName</key>
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<string>Local Baseline</string>
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</dict>
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</dict>
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<key>testMalformedJSONPerformance()</key>
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<dict>
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<key>com.apple.XCTPerformanceMetric_WallClockTime</key>
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<dict>
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<key>baselineAverage</key>
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<real>0.010174</real>
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<key>baselineIntegrationDisplayName</key>
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<string>Local Baseline</string>
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</dict>

‎Sources/SwiftJSONSanitizer/Benchmark.swift‎

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import Foundation
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// Simple benchmark to measure performance improvements
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func benchmark() {
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let largeJSON = generateLargeJSON(depth: 6, breadth: 8)
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let iterations = 100
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print("JSON size: \(largeJSON.count) bytes")
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// Warm up
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_ = SwiftJSONSanitizer.sanitize(largeJSON, options: .minify)
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// Benchmark minification
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let minifyStart = CFAbsoluteTimeGetCurrent()
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for _ in 0..<iterations {
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_ = SwiftJSONSanitizer.sanitize(largeJSON, options: .minify)
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}
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let minifyTime = CFAbsoluteTimeGetCurrent() - minifyStart
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// Benchmark pretty print
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let prettyStart = CFAbsoluteTimeGetCurrent()
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for _ in 0..<iterations {
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_ = SwiftJSONSanitizer.sanitize(largeJSON, options: .prettyPrint)
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}
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let prettyTime = CFAbsoluteTimeGetCurrent() - prettyStart
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print("Minify: \(minifyTime / Double(iterations) * 1000)ms per iteration")
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print("Pretty: \(prettyTime / Double(iterations) * 1000)ms per iteration")
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print("Total minify time: \(minifyTime)s")
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print("Total pretty time: \(prettyTime)s")
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}
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private func generateLargeJSON(depth: Int, breadth: Int) -> String {
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func generateObject(_ currentDepth: Int) -> String {
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if currentDepth == 0 {
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return "{\"leaf\":\"value with some text content here\"}"
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}
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var object = "{"
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for i in 0..<breadth {
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object += "\"key\(i)\":"
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if i % 3 == 0 {
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object += "[1,2,3,4,5" // Missing closing bracket
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} else if i % 3 == 1 {
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object += generateObject(currentDepth - 1)
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} else {
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object += "\"string value with special chars: {}, []" // Missing closing quote
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}
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if i < breadth - 1 {
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object += ","
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}
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}
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// Randomly omit closing brace
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if currentDepth % 2 == 0 {
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object += "}"
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}
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return object
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}
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return generateObject(depth)
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}

‎Sources/SwiftJSONSanitizer/BenchmarkComparison.swift‎

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import Foundation
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// Benchmark comparison between original and optimized versions
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public struct BenchmarkComparison {
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public static func run() {
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print("=== SwiftJSONSanitizer Performance Benchmark ===\n")
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// Generate test data
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let smallJSON = generateJSON(depth: 3, breadth: 5)
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let mediumJSON = generateJSON(depth: 4, breadth: 6)
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let largeJSON = generateJSON(depth: 5, breadth: 8)
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let veryLargeJSON = generateJSON(depth: 6, breadth: 8)
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print("Test data sizes:")
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print("- Small: \(smallJSON.count) bytes")
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print("- Medium: \(mediumJSON.count) bytes")
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print("- Large: \(largeJSON.count) bytes")
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print("- Very Large: \(veryLargeJSON.count) bytes")
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print("")
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// Warm up
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_ = SwiftJSONSanitizer.sanitize(smallJSON, options: .minify)
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_ = SwiftJSONSanitizer.sanitize(smallJSON, options: .prettyPrint)
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// Run benchmarks
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print("Running benchmarks (100 iterations each)...")
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print("")
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// Small JSON
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print("Small JSON:")
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benchmarkSize(smallJSON, label: "Small", iterations: 100)
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// Medium JSON
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print("\nMedium JSON:")
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benchmarkSize(mediumJSON, label: "Medium", iterations: 100)
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// Large JSON
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print("\nLarge JSON:")
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benchmarkSize(largeJSON, label: "Large", iterations: 100)
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// Very Large JSON
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print("\nVery Large JSON:")
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benchmarkSize(veryLargeJSON, label: "Very Large", iterations: 50)
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// Memory pressure test
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print("\n=== Memory Pressure Test ===")
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memoryPressureTest()
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}
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51+
private static func benchmarkSize(_ json: String, label: String, iterations: Int) {
52+
// Minify benchmark
53+
let minifyStart = CFAbsoluteTimeGetCurrent()
54+
for _ in 0..<iterations {
55+
_ = SwiftJSONSanitizer.sanitize(json, options: .minify)
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}
57+
let minifyTime = CFAbsoluteTimeGetCurrent() - minifyStart
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// Pretty print benchmark
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let prettyStart = CFAbsoluteTimeGetCurrent()
61+
for _ in 0..<iterations {
62+
_ = SwiftJSONSanitizer.sanitize(json, options: .prettyPrint)
63+
}
64+
let prettyTime = CFAbsoluteTimeGetCurrent() - prettyStart
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66+
// Calculate and print results
67+
let minifyPerIteration = (minifyTime / Double(iterations)) * 1000
68+
let prettyPerIteration = (prettyTime / Double(iterations)) * 1000
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70+
print(" Minify: \(String(format: "%.3f", minifyPerIteration))ms per iteration")
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print(" Pretty: \(String(format: "%.3f", prettyPerIteration))ms per iteration")
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print(" Throughput (minify): \(String(format: "%.1f", Double(json.count * iterations) / minifyTime / 1_000_000)) MB/s")
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print(" Throughput (pretty): \(String(format: "%.1f", Double(json.count * iterations) / prettyTime / 1_000_000)) MB/s")
74+
}
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76+
private static func memoryPressureTest() {
77+
let hugeJSON = generateJSON(depth: 7, breadth: 5)
78+
print("Testing with \(hugeJSON.count) bytes...")
79+
80+
let start = CFAbsoluteTimeGetCurrent()
81+
_ = SwiftJSONSanitizer.sanitize(hugeJSON, options: .prettyPrint)
82+
let time = CFAbsoluteTimeGetCurrent() - start
83+
84+
print(" Time: \(String(format: "%.3f", time * 1000))ms")
85+
print(" Throughput: \(String(format: "%.1f", Double(hugeJSON.count) / time / 1_000_000)) MB/s")
86+
}
87+
88+
private static func generateJSON(depth: Int, breadth: Int) -> String {
89+
func generateObject(_ currentDepth: Int) -> String {
90+
if currentDepth == 0 {
91+
return "{\"leaf\":\"value with some text content here that makes it realistic\"}"
92+
}
93+
94+
var object = "{"
95+
for i in 0..<breadth {
96+
object += "\"key\(i)\":"
97+
if i % 4 == 0 {
98+
object += "[1,2,3,4,5" // Missing closing bracket
99+
} else if i % 4 == 1 {
100+
object += generateObject(currentDepth - 1)
101+
} else if i % 4 == 2 {
102+
object += "\"string value with special chars: {}, [], and a comma," // Missing closing quote
103+
} else {
104+
object += "true"
105+
}
106+
if i < breadth - 1 {
107+
object += ","
108+
}
109+
}
110+
// Randomly omit closing brace
111+
if currentDepth % 2 == 0 {
112+
object += "}"
113+
}
114+
return object
115+
}
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117+
return generateObject(depth)
118+
}
119+
}
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// Function to run from command line
122+
func runBenchmark() {
123+
BenchmarkComparison.run()
124+
}

‎Sources/SwiftJSONSanitizer/StringBuilder.swift‎

Lines changed: 13 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -7,52 +7,47 @@
77

88
/// A more efficient string builder for constructing large strings
99
struct StringBuilder {
10-
private var buffer: [Character]
11-
private var stringCache: String?
10+
private var buffer: String
1211

1312
init(capacity: Int = 256) {
14-
self.buffer = []
13+
self.buffer = ""
1514
self.buffer.reserveCapacity(capacity)
1615
}
1716

1817
mutating func append(_ character: Character) {
1918
buffer.append(character)
20-
stringCache = nil
2119
}
2220

2321
mutating func append(_ string: String) {
24-
buffer.append(contentsOf: string)
25-
stringCache = nil
22+
buffer.append(string)
2623
}
2724

2825
mutating func remove(at index: Int) {
29-
buffer.remove(at: index)
30-
stringCache = nil
26+
let idx = buffer.index(buffer.startIndex, offsetBy: index)
27+
buffer.remove(at: idx)
3128
}
3229

3330
mutating func removeLast() {
3431
buffer.removeLast()
35-
stringCache = nil
3632
}
3733

3834
var last: Character? {
3935
buffer.last
4036
}
4137

4238
func lastIndex(where predicate: (Character) -> Bool) -> Int? {
43-
buffer.lastIndex(where: predicate)
39+
if let idx = buffer.lastIndex(where: predicate) {
40+
return buffer.distance(from: buffer.startIndex, to: idx)
41+
}
42+
return nil
4443
}
4544

4645
subscript(index: Int) -> Character {
47-
buffer[index]
46+
let idx = buffer.index(buffer.startIndex, offsetBy: index)
47+
return buffer[idx]
4848
}
4949

50-
mutating func toString() -> String {
51-
if let cached = stringCache {
52-
return cached
53-
}
54-
let result = String(buffer)
55-
stringCache = result
56-
return result
50+
func toString() -> String {
51+
return buffer
5752
}
5853
}

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