feat: add PTR as an alias for I64

.gitignore

@@ -28,3 +28,4 @@ replay_pid*
 .settings
 
 target/
+.idea/

src/main/java/org/extism/sdk/HostFunction.java

@@ -35,11 +35,11 @@ public HostFunction(String name, LibExtism.ExtismValType[] params, LibExtism.Ext
                          int nOutputs,
                          Pointer data) -> {
 
-            LibExtism.ExtismVal[] outputs = (LibExtism.ExtismVal []) outs.toArray(nOutputs);
+            LibExtism.ExtismVal[] outputs = (LibExtism.ExtismVal[]) outs.toArray(nOutputs);
 
             f.invoke(
                     new ExtismCurrentPlugin(currentPlugin),
-                    (LibExtism.ExtismVal []) inputs.toArray(nInputs),
+                    (LibExtism.ExtismVal[]) inputs.toArray(nInputs),
                     outputs,
                     userData
             );
@@ -70,7 +70,12 @@ void convertOutput(LibExtism.ExtismVal original, LibExtism.ExtismVal fromHostFun
             original.v.i32 = fromHostFunction.v.i32;
         } else if (fromHostFunction.t == LibExtism.ExtismValType.I64.v) {
             original.v.setType(Long.TYPE);
-            original.v.i64 = fromHostFunction.v.i64;
+            // PTR is an alias for I64
+            if (fromHostFunction.v.i64 == 0 && fromHostFunction.v.ptr > 0) {
+                original.v.i64 = fromHostFunction.v.ptr;
+            } else {
+                original.v.i64 = fromHostFunction.v.i64;
+            }
         } else if (fromHostFunction.t == LibExtism.ExtismValType.F32.v) {
             original.v.setType(Float.TYPE);
             original.v.f32 = fromHostFunction.v.f32;
@@ -93,7 +98,7 @@ public HostFunction withNamespace(String name) {
     }
 
     public void free() {
-        if (!this.freed){
+        if (!this.freed) {
             LibExtism.INSTANCE.extism_function_free(this.pointer);
             this.freed = true;
         }

src/main/java/org/extism/sdk/LibExtism.java

@@ -29,17 +29,19 @@ class ExtismVal extends Structure {
         public int t;
         public ExtismValUnion v;
     }
-
     class ExtismValUnion extends Union {
         public int i32;
         public long i64;
+        public long ptr;
         public float f32;
         public double f64;
     }
 
     enum ExtismValType {
         I32(0),
         I64(1),
+        // PTR is an alias for I64
+        PTR(1),
         F32(2),
         F64(3),
         V128(4),

src/test/java/org/extism/sdk/PluginTests.java

@@ -197,6 +197,53 @@ public MyUserData(String data1, int data2) {
         }
     }
 
+    @Test
+    public void shouldAllowInvokeHostFunctionFromPDKUsingPTR() {
+        var parametersTypes = new LibExtism.ExtismValType[]{LibExtism.ExtismValType.PTR};
+        var resultsTypes = new LibExtism.ExtismValType[]{LibExtism.ExtismValType.PTR};
+
+        class MyUserData extends HostUserData {
+            private String data1;
+            private int data2;
+
+            public MyUserData(String data1, int data2) {
+                super();
+                this.data1 = data1;
+                this.data2 = data2;
+            }
+        }
+
+        ExtismFunction helloWorldFunction = (ExtismFunction<MyUserData>) (plugin, params, returns, data) -> {
+            System.out.println("Hello from Java Host Function!");
+            System.out.println(String.format("Input string received from plugin, %s", plugin.inputString(params[0])));
+
+            int offs = plugin.alloc(4);
+            Pointer mem = plugin.memory();
+            mem.write(offs, "test".getBytes(), 0, 4);
+            returns[0].v.ptr = offs;
+
+            data.ifPresent(d -> System.out.println(String.format("Host user data, %s, %d", d.data1, d.data2)));
+        };
+
+        HostFunction helloWorld = new HostFunction<>(
+                "hello_world",
+                parametersTypes,
+                resultsTypes,
+                helloWorldFunction,
+                Optional.of(new MyUserData("test", 2))
+        );
+
+        HostFunction[] functions = {helloWorld};
+
+        Manifest manifest = new Manifest(Arrays.asList(CODE.pathWasmFunctionsSource()));
+        String functionName = "count_vowels";
+
+        try (var plugin = new Plugin(manifest, true, functions)) {
+            var output = plugin.call(functionName, "this is a test");
+            assertThat(output).isEqualTo("test");
+        }
+    }
+
     @Test
     public void shouldAllowInvokeHostFunctionWithoutUserData() {