Replace unsafe iteration with use of Span

.github/workflows/ci.yml

@@ -21,18 +21,14 @@ jobs:
     name: soundness
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
     with:
-      # https://github.com/swiftlang/swift-package-manager/issues/8103
-      api_breakage_check_enabled: false
-      # swift:6.2-noble leads to issues with Snippets
-      # e.g. https://github.com/apple/swift-homomorphic-encryption/actions/runs/18144503507/job/51643132814#step:5:1087
-      docs_check_container_image: swift:6.1-noble
+      docs_check_container_image: swift:6.2.2-noble
       format_check_enabled: false
   tests:
     name: swifttests
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
       enable_windows_checks: false
-      linux_exclude_swift_versions: "[{\"swift_version\": \"5.9\"}, {\"swift_version\": \"5.10\"}]"
+      linux_exclude_swift_versions: "[{\"swift_version\": \"5.9\"}, {\"swift_version\": \"5.10\"}, {\"swift_version\": \"6.0\"}, {\"swift_version\": \"6.1\"}]"
       linux_env_vars: SWIFT_HOMOMORPHIC_ENCRYPTION_ENABLE_BENCHMARKING=1
       linux_pre_build_command: "apt-get update && apt-get install -y libjemalloc-dev"
       linux_build_command: >

.spi.yml

@@ -12,4 +12,4 @@ builder:
         - PNNSProcessDatabase
         - PrivateInformationRetrieval
         - PrivateNearestNeighborSearch
-      swift_version: 6.0
+      swift_version: 6.2

.swiftformat

@@ -8,4 +8,4 @@
 --nospaceoperators ..<, ...
 --ranges no-space
 --self init-only
---swiftversion 6.0
+--swiftversion 6.2

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 6.0
+// swift-tools-version: 6.2
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 // Remember to update CI if changing
 
@@ -108,12 +108,13 @@ let package = Package(
                 "CUtil",
                 "ModularArithmetic",
             ],
+            exclude: ["HomomorphicEncryption.docc"],
             swiftSettings: librarySettings),
         .target(
             name: "HomomorphicEncryptionProtobuf",
             dependencies: ["HomomorphicEncryption",
                            .product(name: "SwiftProtobuf", package: "swift-protobuf")],
-            exclude: ["generated/README.md"],
+            exclude: ["generated/README.md", "HomomorphicEncryptionProtobuf.docc"],
             swiftSettings: librarySettings),
         .target(
             name: "_HomomorphicEncryptionExtras",
@@ -124,6 +125,7 @@ let package = Package(
             dependencies: ["HomomorphicEncryption",
                            .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
                            .product(name: "Numerics", package: "swift-numerics")],
+            exclude: ["PrivateInformationRetrieval.docc"],
             swiftSettings: librarySettings),
         .target(
             name: "PrivateNearestNeighborSearch",
@@ -133,14 +135,15 @@ let package = Package(
                 "HomomorphicEncryption",
                 "_HomomorphicEncryptionExtras",
             ],
+            exclude: ["PrivateNearestNeighborSearch.docc"],
             swiftSettings: librarySettings),
         .target(
             name: "ApplicationProtobuf",
             dependencies: ["HomomorphicEncryptionProtobuf",
                            "PrivateInformationRetrieval",
                            "PrivateNearestNeighborSearch",
                            .product(name: "SwiftProtobuf", package: "swift-protobuf")],
-            exclude: ["generated/README.md", "protobuf_module_mappings.txtpb"],
+            exclude: ["ApplicationProtobuf.docc", "generated/README.md", "protobuf_module_mappings.txtpb"],
             swiftSettings: librarySettings),
         .target(
             name: "_TestUtilities",
@@ -159,6 +162,7 @@ let package = Package(
                 "HomomorphicEncryption",
                 "ApplicationProtobuf",
             ],
+            exclude: ["PIRGenerateDatabase.docc"],
             swiftSettings: executableSettings),
         .executableTarget(
             name: "PIRProcessDatabase",
@@ -169,6 +173,7 @@ let package = Package(
                 "HomomorphicEncryption",
                 .product(name: "Logging", package: "swift-log"),
             ],
+            exclude: ["PIRProcessDatabase.docc"],
             swiftSettings: executableSettings),
         .executableTarget(
             name: "PIRShardDatabase",
@@ -177,6 +182,7 @@ let package = Package(
                 "HomomorphicEncryption",
                 "ApplicationProtobuf",
             ],
+            exclude: ["PIRShardDatabase.docc"],
             swiftSettings: executableSettings),
         .executableTarget(
             name: "PNNSGenerateDatabase",
@@ -185,6 +191,7 @@ let package = Package(
                 "HomomorphicEncryption",
                 "ApplicationProtobuf",
             ],
+            exclude: ["PNNSGenerateDatabase.docc"],
             swiftSettings: executableSettings),
         .executableTarget(
             name: "PNNSProcessDatabase",
@@ -195,6 +202,7 @@ let package = Package(
                 "HomomorphicEncryption",
                 .product(name: "Logging", package: "swift-log"),
             ],
+            exclude: ["PNNSProcessDatabase.docc"],
             swiftSettings: executableSettings),
         .testTarget(
             name: "HomomorphicEncryptionTests",
@@ -342,6 +350,6 @@ if enableDocCPlugin {
 // Set the minimum macOS version for the package
 #if canImport(Darwin)
 package.platforms = [
-    .macOS(.v15), // Constrained by UInt128 support
+    .macOS(.v26), // Constrained by use of Span
 ]
 #endif

README.md

@@ -136,7 +136,7 @@ The following table maps Swift Homomorphic Encryption package versions to requir
 Package version | Swift version | Xcode version
 ----------------|---------------|-----------------------------------------
 1.0.x           | >= Swift 5.10 | >= Xcode 15.3
-main            | >= Swift 6.0  | >= Xcode 16.1
+main            | >= Swift 6.2  | >= Xcode 26
 
 ### Source Stability
 Swift Homomorphic Encryption follows [Semantic Versioning 2.0.0](https://semver.org/spec/v2.0.0.html). Source breaking changes to the public API can only land in a new major version, with the following exception:
@@ -155,7 +155,7 @@ We'd like this package to quickly embrace Swift language and toolchain improveme
 Developing Swift Homomorphic Encryption requires:
 * [Nick Lockwood SwiftFormat](https://github.com/nicklockwood/SwiftFormat), 0.58.6
 * [pre-commit](https://pre-commit.com)
-* [swift-format](https://github.com/swiftlang/swift-format), 600.0.0
+* [swift-format](https://github.com/swiftlang/swift-format), 602.0.0
 * [swift-protobuf](https://github.com/apple/swift-protobuf), 1.31.1
 * [SwiftLint](https://github.com/realm/SwiftLint), 0.62.2
 

Sources/HomomorphicEncryption/Array2d.swift

@@ -76,36 +76,31 @@ public struct Array2d<T: Equatable & AdditiveArithmetic & Sendable>: Equatable,
             columnCount: columnCount)
     }
 
-    /// Provides scoped access to the underlying buffer storing the array's data.
+    /// Provides scoped access to the underlying buffer storing the array's data using a Span.
     ///
     /// Use this method when you need temporary read-only access to the array's contiguous storage.
-    /// The buffer pointer is only valid for the duration of the closure's execution.
     ///
-    /// - Parameter body: A closure that takes an `UnsafeBufferPointer` to the array's data.
-    ///   The buffer pointer argument is valid only for the duration of the closure's execution.
+    /// - Parameter body: A closure that takes a `Span<T>` to the array's data.
     /// - Returns: The return value of the `body` closure.
     /// - Throws: Rethrows any error thrown by the `body` closure.
-    public func withUnsafeData<Return>(_ body: (UnsafeBufferPointer<T>) throws -> Return) rethrows -> Return {
-        try data.withUnsafeBufferPointer { pointer in
-            try body(pointer)
-        }
+    @inlinable
+    public func withDataSpan<Return>(_ body: (Span<T>) throws -> Return) rethrows -> Return {
+        try body(data.span)
     }
 
     /// Provides scoped access to the underlying buffer storing the array's data for mutation.
     ///
     /// Use this method when you need temporary read-write access to the array's contiguous storage.
-    /// The buffer pointer is only valid for the duration of the closure's execution.
     ///
-    /// - Parameter body: A closure that takes an `UnsafeMutableBufferPointer` to the array's data.
-    ///   The buffer pointer argument is valid only for the duration of the closure's execution.
+    /// - Parameter body: A closure that takes a `MutableSpan<T>` to the array's data.
     /// - Returns: The return value of the `body` closure.
     /// - Throws: Rethrows any error thrown by the `body` closure.
-    public mutating func withUnsafeMutableData<Return>(_ body: (UnsafeMutableBufferPointer<T>) throws
-        -> Return) rethrows -> Return
+    @inlinable
+    public mutating func withMutableDataSpan<Return>(_ body: (inout MutableSpan<T>) throws -> Return) rethrows
+        -> Return
     {
-        try data.withUnsafeMutableBufferPointer { pointer in
-            try body(pointer)
-        }
+        var span = data.mutableSpan
+        return try body(&span)
     }
 }
 

Sources/HomomorphicEncryption/Bfv/Bfv+Encrypt.swift

@@ -85,61 +85,57 @@ extension Bfv {
 
         let plaintextIndices = plaintext.poly.polyIndices(rnsIndex: 0)
         var adjust = plaintext
-        // swiftlint:disable:next closure_body_length
-        plaintext.poly.data.data.withUnsafeBufferPointer { plaintextData in
-            adjust.poly.data.data.withUnsafeMutableBufferPointer { adjustPtr in
-                let t = rnsTool.t.modulus
-                if T.DoubleWidth(t.multipliedFullWidth(by: t)) <= T.max {
-                    // Prefer single-word division, since it's faster
-                    for index in plaintextIndices {
-                        var adjustCoeff = rnsTool.qModT &* plaintextData[index]
-                        adjustCoeff &+= rnsTool.tThreshold
-                        adjustPtr[index] = adjustCoeff.dividingFloor(by: rnsTool.t)
-                    }
-                } else {
-                    let tThreshold = Scalar.DoubleWidth(rnsTool.tThreshold)
-                    for index in plaintextIndices {
-                        var adjustCoeff = Scalar
-                            .DoubleWidth(rnsTool.qModT.multipliedFullWidth(by: plaintextData[index]))
-                        adjustCoeff &+= tThreshold
-                        adjustPtr[index] = adjustCoeff.dividingFloor(by: rnsTool.t).low
-                    }
-                }
+
+        let plaintextData = plaintext.poly.data.data.span
+        var adjustSpan = adjust.poly.data.data.mutableSpan
+        let t = rnsTool.t.modulus
+        if T.DoubleWidth(t.multipliedFullWidth(by: t)) <= T.max {
+            // Prefer single-word division, since it's faster
+            for index in plaintextIndices {
+                var adjustCoeff = rnsTool.qModT &* plaintextData[index]
+                adjustCoeff &+= rnsTool.tThreshold
+                adjustSpan[index] = adjustCoeff.dividingFloor(by: rnsTool.t)
+            }
+        } else {
+            let tThreshold = Scalar.DoubleWidth(rnsTool.tThreshold)
+            for index in plaintextIndices {
+                var adjustCoeff = Scalar
+                    .DoubleWidth(rnsTool.qModT.multipliedFullWidth(by: plaintextData[index]))
+                adjustCoeff &+= tThreshold
+                adjustSpan[index] = adjustCoeff.dividingFloor(by: rnsTool.t).low
             }
+        }
 
-            var c0 = ciphertext.polys[0]
-            let c1 = ciphertext.polys[1] // used for polynomial index computation only
-
-            switch op {
-            case PlaintextTranslateOp.Add:
-                c0.data.data.withUnsafeMutableBufferPointer { c0Ptr in
-                    for (rnsIndex, rnsDelta) in rnsTool.qDivT.enumerated() {
-                        for (plainIndex, cipherIndex) in c1.polyIndices(rnsIndex: rnsIndex).enumerated() {
-                            let plainTimesDelta = rnsDelta.multiplyMod(plaintextData[plainIndex])
-                            let roundQTimesMt = plainTimesDelta.addMod(
-                                adjust[plainIndex],
-                                modulus: rnsDelta.modulus)
-                            c0Ptr[cipherIndex] = c0Ptr[cipherIndex].addMod(roundQTimesMt, modulus: rnsDelta.modulus)
-                        }
-                    }
+        var c0 = ciphertext.polys[0]
+        let c1 = ciphertext.polys[1] // used for polynomial index computation only
+
+        switch op {
+        case PlaintextTranslateOp.Add:
+            var c0Span = c0.data.data.mutableSpan
+            for (rnsIndex, rnsDelta) in rnsTool.qDivT.enumerated() {
+                for (plainIndex, cipherIndex) in c1.polyIndices(rnsIndex: rnsIndex).enumerated() {
+                    let plainTimesDelta = rnsDelta.multiplyMod(plaintextData[plainIndex])
+                    let roundQTimesMt = plainTimesDelta.addMod(
+                        adjust[plainIndex],
+                        modulus: rnsDelta.modulus)
+                    c0Span[cipherIndex] = c0Span[cipherIndex].addMod(roundQTimesMt, modulus: rnsDelta.modulus)
                 }
-            case PlaintextTranslateOp.Subtract:
-                c0.data.data.withUnsafeMutableBufferPointer { c0Ptr in
-                    for (rnsIndex, rnsDelta) in rnsTool.qDivT.enumerated() {
-                        for (plainIndex, cipherIndex) in c1.polyIndices(rnsIndex: rnsIndex).enumerated() {
-                            let plainTimesDelta = rnsDelta.multiplyMod(plaintextData[plainIndex])
-                            let roundQTimesMt = plainTimesDelta.addMod(
-                                adjust[plainIndex],
-                                modulus: rnsDelta.modulus)
-                            c0Ptr[cipherIndex] = c0Ptr[cipherIndex].subtractMod(
-                                roundQTimesMt,
-                                modulus: rnsDelta.modulus)
-                        }
-                    }
+            }
+        case PlaintextTranslateOp.Subtract:
+            var c0Span = c0.data.data.mutableSpan
+            for (rnsIndex, rnsDelta) in rnsTool.qDivT.enumerated() {
+                for (plainIndex, cipherIndex) in c1.polyIndices(rnsIndex: rnsIndex).enumerated() {
+                    let plainTimesDelta = rnsDelta.multiplyMod(plaintextData[plainIndex])
+                    let roundQTimesMt = plainTimesDelta.addMod(
+                        adjust[plainIndex],
+                        modulus: rnsDelta.modulus)
+                    c0Span[cipherIndex] = c0Span[cipherIndex].subtractMod(
+                        roundQTimesMt,
+                        modulus: rnsDelta.modulus)
                 }
             }
-            ciphertext.polys[0] = c0
         }
+        ciphertext.polys[0] = c0
     }
 
     @inlinable

Sources/HomomorphicEncryption/Bfv/Bfv+Keys.swift

@@ -179,25 +179,23 @@ extension Bfv {
                 for (index, poly) in keyCiphers[decomposeIndex].polys.enumerated() {
                     let accIndex = poly.data.index(row: index, column: 0)
                     let polyIndex = poly.data.index(row: keyIndex, column: 0)
-                    poly.data.data.withUnsafeBufferPointer { polyPtr in
-                        for columnIndex in 0..<degree {
-                            let prod = bufferSlice[columnIndex]
-                                .multipliedFullWidth(by: polyPtr[polyIndex &+ columnIndex])
-                            // Overflow avoided by `maxLazyProductAccumulationCount()` check during context
-                            // initialization
-                            accumulator[accIndex &+ columnIndex] &+= T.DoubleWidth(prod)
-                        }
+                    let polySpan = poly.data.data.span
+                    for columnIndex in 0..<degree {
+                        let prod = bufferSlice[columnIndex]
+                            .multipliedFullWidth(by: polySpan[polyIndex &+ columnIndex])
+                        // Overflow avoided by `maxLazyProductAccumulationCount()` check during context
+                        // initialization
+                        accumulator[accIndex &+ columnIndex] &+= T.DoubleWidth(prod)
                     }
                 }
             }
             let prodIndex = ciphertextProd.polys[0].data.index(row: rnsIndex, column: 0)
             for rowIndex in ciphertextProd.polys.indices {
                 let accIndex = accumulator.index(row: rowIndex, column: 0)
-                ciphertextProd.polys[rowIndex].data.data.withUnsafeMutableBufferPointer { ciphertextProdPtr in
-                    for columnIndex in 0..<degree {
-                        ciphertextProdPtr[prodIndex &+ columnIndex] = keyModulus
-                            .reduce(accumulator[accIndex &+ columnIndex])
-                    }
+                var ciphertextProdSpan = ciphertextProd.polys[rowIndex].data.data.mutableSpan
+                for columnIndex in 0..<degree {
+                    ciphertextProdSpan[prodIndex &+ columnIndex] = keyModulus
+                        .reduce(accumulator[accIndex &+ columnIndex])
                 }
             }
         }

Sources/HomomorphicEncryption/Bfv/Bfv.swift

@@ -293,13 +293,11 @@ public enum Bfv<T: ScalarType>: HeScheme {
     {
         let poly = result.polys[0]
         for (polyIndex, accumulatorPoly) in accumulator.enumerated() {
-            accumulatorPoly.data.withUnsafeBufferPointer { accumulatorPolyPtr in
-                result.polys[polyIndex].data.data.withUnsafeMutableBufferPointer { resultPtr in
-                    for (rnsIndex, modulus) in poly.polyContext().reduceModuli.enumerated() {
-                        for index in poly.polyIndices(rnsIndex: rnsIndex) {
-                            resultPtr[index] = modulus.reduce(accumulatorPolyPtr[index])
-                        }
-                    }
+            let accumulatorPolySpan = accumulatorPoly.data.span
+            var resultSpan = result.polys[polyIndex].data.data.mutableSpan
+            for (rnsIndex, modulus) in poly.polyContext().reduceModuli.enumerated() {
+                for index in poly.polyIndices(rnsIndex: rnsIndex) {
+                    resultSpan[index] = modulus.reduce(accumulatorPolySpan[index])
                 }
             }
         }

Sources/HomomorphicEncryption/CrtComposer.swift

@@ -87,7 +87,7 @@ public struct _CrtComposer<T: ScalarType>: Sendable {
             for column in 0..<data.columnCount {
                 let tmp = V(inversePuncturedProduct.multiplyMod(data[
                     row,
-                    column
+                    column,
                 ]))
                 let addend = tmp &* puncturedProduct
                 products[column] = products[column].addMod(addend, modulus: q)

Sources/HomomorphicEncryption/HomomorphicEncryption.docc/UsingSwiftHomomorphicEncryption.md

@@ -54,7 +54,7 @@ The following table maps Swift Homomorphic Encryption packgae versions to requir
 Package version | Swift version | Xcode version
 ----------------|---------------|-----------------------------------------
 1.0.x           | >= Swift 5.10 | >= Xcode 15.3
-main            | >= Swift 6.0  | >= Xcode 16.1
+main            | >= Swift 6.2  | >= Xcode 26
 
 ### Source Stability
 Swift Homomorphic Encryption follows [Semantic Versioning 2.0.0](https://semver.org/spec/v2.0.0.html). Source breaking changes to the public API can only land in a new major version, with the following exception: