Fix returning cast to boolean

src/main/java/jnr/ffi/provider/jffi/NumberUtil.java

@@ -20,6 +20,7 @@
 
 import jnr.ffi.NativeType;
 import jnr.ffi.provider.SigType;
+import org.objectweb.asm.Label;
 
 public final class NumberUtil {
     private NumberUtil() {}
@@ -145,6 +146,22 @@ public static void narrow(SkinnyMethodAdapter mv, Class from, Class to) {
         if (!from.equals(to)) {
             if (byte.class == to || short.class == to || char.class == to || int.class == to || boolean.class == to) {
                 if (long.class == from) {
+                    // long x = 0x100000000LL;
+                    // boolean b = x != 0;
+                    // IMO, return false only if the long is  zero.
+                    if (boolean.class == to) {
+                        mv.lconst_0();
+                        mv.lcmp();
+                        Label a = new Label();
+                        mv.ifeq(a);
+                        mv.iconst_1();
+                        Label b = new Label();
+                        mv.go_to(b);
+                        mv.label(a);
+                        mv.iconst_0();
+                        mv.label(b);
+                        return;
+                    }
                     mv.l2i();
                 }
 
@@ -159,8 +176,14 @@ public static void narrow(SkinnyMethodAdapter mv, Class from, Class to) {
 
                 } else if (boolean.class == to) {
                     // Ensure only 0x0 and 0x1 values are used for boolean
+                    Label l0 = new Label();
+                    mv.ifeq(l0);
                     mv.iconst_1();
-                    mv.iand();
+                    Label l1 = new Label();
+                    mv.go_to(l1);
+                    mv.label(l0);
+                    mv.iconst_0();
+                    mv.label(l1);
                 }
             }
         }

src/test/java/jnr/ffi/NumberTest.java

@@ -21,6 +21,7 @@
 import java.util.Random;
 
 import jnr.ffi.annotations.LongLong;
+import jnr.ffi.provider.jffi.NoX86;
 import jnr.ffi.types.*;
 import org.junit.After;
 import org.junit.AfterClass;
@@ -73,10 +74,18 @@ public static interface TestBoolean {
     }
     static TestBoolean testboolean;
 
+    @NoX86
+    public static interface TestBooleanNoX86 {
+        public @int32_t boolean ret_int32_t(@int32_t int l);
+        public @int64_t boolean ret_int64_t(@int64_t long l);
+    }
+    static TestBooleanNoX86 testBooleanNoX86;
+
     @BeforeClass
     public static void setUpClass() throws Exception {
         testlib = TstUtil.loadTestLib(TestLib.class);
         testboolean = TstUtil.loadTestLib(TestBoolean.class);
+        testBooleanNoX86 = TstUtil.loadTestLib(TestBooleanNoX86.class);
     }
 
     @AfterClass
@@ -357,4 +366,21 @@ public long n(long i1, long i2) {
         assertEquals(true, testboolean.ret_int32_t(1));
         assertEquals(true, testboolean.ret_int32_t(2));
     }
+
+    @Test public void testBooleanFromIntNoX86() {
+        for (int i = -3; i <= 3; ++i) {
+            boolean expectResult = i != 0;
+            assertEquals("expect to boolean from '" + i + "'", expectResult, testBooleanNoX86.ret_int32_t(i));
+        }
+    }
+
+    @Test public void testBooleanFromLongNoX86() {
+        for (long i = -3; i <= 3; ++i) {
+            boolean expectResult = i != 0;
+            assertEquals("expect to boolean from '" + i + "'", expectResult, testBooleanNoX86.ret_int64_t(i));
+        }
+        long x = 0x100000000L;
+        assertEquals("expect to boolean from '" + x + "'", true, testBooleanNoX86.ret_int64_t(x));
+    }
+
 }