Android Support

.github/workflows/android.yml

@@ -0,0 +1,20 @@
+name: Android
+
+on:
+    push:
+        branches: [ master ]
+    pull_request:
+        branches: [ master ]
+
+jobs:
+    android:
+        runs-on: ubuntu-24.04
+        name: Android
+
+        steps:
+            -   name: Checkout repository
+                uses: actions/checkout@v4
+            -   name: Build for Android
+                uses: skiptools/swift-android-action@v2
+                with:
+                    run-tests: false

Sources/JPEG/decode.swift

@@ -1768,6 +1768,20 @@ extension JPEG.Data.Spectral:RandomAccessCollection
     ///
     /// -   Returns:
     ///     The plane.
+    #if os(Android) // workaround for an Android toolchain crash in `yield`
+    public
+    subscript(p:Int) -> Plane
+    {
+        get
+        {
+            self.planes[p]
+        }
+        set
+        {
+            self.planes[p] = newValue
+        }
+    }
+    #else
     public
     subscript(p:Int) -> Plane
     {
@@ -1780,6 +1794,7 @@ extension JPEG.Data.Spectral:RandomAccessCollection
             yield &self.planes[p]
         }
     }
+    #endif
     /// Returns the index of the plane storing the color channel represented
     /// by the given component key, or `nil` if the component key is a
     /// non-recognized component.

Sources/JPEGSystem/os.swift

@@ -8,11 +8,13 @@ import JPEG
     import Darwin
 #elseif os(Linux)
     import Glibc
+#elseif os(Android)
+    import Android
 #else
     #warning("unsupported or untested platform (please open an issue at https://github.com/tayloraswift/swift-jpeg/issues)")
 #endif
 
-#if os(macOS) || os(Linux)
+#if os(macOS) || os(Linux) || os(Android)
 
 /// A namespace for platform-dependent functionality.
 ///
@@ -25,7 +27,11 @@ enum System
     public
     enum File
     {
+        #if os(Android)
+        typealias Descriptor = OpaquePointer
+        #else
         typealias Descriptor = UnsafeMutablePointer<FILE>
+        #endif
 
         /// A type for reading data from files on disk.
         public
@@ -102,7 +108,12 @@ extension System.File.Source
         {
             (buffer:inout UnsafeMutableBufferPointer<UInt8>, count:inout Int) in
 
-            count = fread(buffer.baseAddress, MemoryLayout<UInt8>.stride,
+            #if os(Android)
+            let baseAddress = buffer.baseAddress!
+            #else
+            let baseAddress = buffer.baseAddress
+            #endif
+            count = fread(baseAddress, MemoryLayout<UInt8>.stride,
                 capacity, self.descriptor)
         }
 
@@ -210,7 +221,12 @@ extension System.File.Destination
     {
         let count:Int = buffer.withUnsafeBufferPointer
         {
-            fwrite($0.baseAddress, MemoryLayout<UInt8>.stride,
+            #if os(Android)
+            let baseAddress = $0.baseAddress!
+            #else
+            let baseAddress = $0.baseAddress
+            #endif
+            return fwrite(baseAddress, MemoryLayout<UInt8>.stride,
                 $0.count, self.descriptor)
         }