June 2018 Update

Task/Use-another-language-to-call-a-function/Kotlin/use-another-language-to-call-a-function-1.kotlin

@@ -0,0 +1,14 @@
+// Kotlin Native v0.6
+
+import kotlinx.cinterop.*
+import platform.posix.*
+
+fun query(data: CPointer<ByteVar>, length: CPointer<size_tVar>): Int {
+    val s = "Here am I"
+    val strLen = s.length
+    val bufferSize = length.pointed.value
+    if (strLen > bufferSize) return 0  // buffer not large enough
+    for (i in 0 until strLen) data[i] = s[i].toByte()
+    length.pointed.value = strLen.signExtend<size_t>()
+    return 1
+}

Task/Use-another-language-to-call-a-function/Kotlin/use-another-language-to-call-a-function-2.kotlin

@@ -0,0 +1,35 @@
+#ifndef KONAN_LIBQUERY_H
+#define KONAN_LIBQUERY_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+typedef unsigned char   libQuery_KBoolean;
+typedef char            libQuery_KByte;
+typedef unsigned short  libQuery_KChar;
+typedef short           libQuery_KShort;
+typedef int             libQuery_KInt;
+typedef long long       libQuery_KLong;
+typedef float           libQuery_KFloat;
+typedef double          libQuery_KDouble;
+typedef void*           libQuery_KNativePtr;
+struct libQuery_KType;
+typedef struct libQuery_KType libQuery_KType;
+
+typedef struct {
+  /* Service functions. */
+  void (*DisposeStablePointer)(libQuery_KNativePtr ptr);
+  void (*DisposeString)(const char* string);
+  libQuery_KBoolean (*IsInstance)(libQuery_KNativePtr ref, const libQuery_KType* type);
+
+  /* User functions. */
+  struct {
+    struct {
+      libQuery_KInt (*query)(void* data, void* length);
+    } root;
+  } kotlin;
+} libQuery_ExportedSymbols;
+extern libQuery_ExportedSymbols* libQuery_symbols(void);
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+#endif  /* KONAN_LIBQUERY_H */

Task/Use-another-language-to-call-a-function/Kotlin/use-another-language-to-call-a-function-3.kotlin

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "libQuery_api.h"
+
+static int Query (char * Data, size_t * Length)
+{
+    return libQuery_symbols() -> kotlin.root.query(Data, Length);
+}
+
+int main (int argc, char * argv [])
+{
+    char     Buffer [1024];
+    size_t   Size = sizeof (Buffer);
+
+    if (0 == Query (Buffer, &Size))
+    {
+        printf ("failed to call Query\n");
+    }
+    else
+    {
+        char * Ptr = Buffer;
+        while (Size-- > 0) putchar (*Ptr++);
+        putchar ('\n');
+    }
+}

Task/Use-another-language-to-call-a-function/Scala/use-another-language-to-call-a-function-1.scala

@@ -0,0 +1,12 @@
+/* Query.scala */
+object Query {
+  def call(data: Array[Byte], length: Array[Int]): Boolean = {
+    val message = "Here am I"
+    val mb = message.getBytes("utf-8")
+    if (length(0) >= mb.length) {
+      length(0) = mb.length
+      System.arraycopy(mb, 0, data, 0, mb.length)
+      true
+    } else false
+  }
+}

Task/Use-another-language-to-call-a-function/Scala/use-another-language-to-call-a-function-2.scala

@@ -0,0 +1,105 @@
+/* query-jni.c */
+#include <stdio.h>
+#include <stdlib.h>
+#include <jni.h>
+
+static JavaVM *jvm = NULL;
+static JNIEnv *jenv = NULL;
+
+static void die(const char *message) {
+    fprintf(stderr, "%s\n", message);
+    exit(1);
+}
+
+static void oom(void) {
+    die("Query: out of memory");
+}
+
+static void except(void) {
+    if ((*jenv)->ExceptionCheck(jenv))
+	die("Query: unexpected Java exception");
+}
+
+static void do_at_exit(void) {
+    (*jvm)->DestroyJavaVM(jvm);
+}
+
+static void require_jvm(void) {
+    JavaVMInitArgs args;
+
+    if (jvm)
+	return;
+
+    args.version = JNI_VERSION_1_4;
+    args.nOptions = 0;
+    args.options = NULL;
+    args.ignoreUnrecognized = JNI_FALSE;
+    if (JNI_CreateJavaVM(&jvm, (void **)&jenv, &args) != JNI_OK)
+	die("Query: can't create Java VM");
+    atexit(do_at_exit);
+}
+
+int Query(char *data, size_t *length) {
+    jclass cQuery;
+    jmethodID mcall;
+    jintArray jlength;
+    jint jlength0;
+    jbyteArray jdata;
+    jboolean result;
+
+    jlength0 = (jint)length[0];
+    if ((size_t)jlength0 != length[0])
+	die("Query: length is too large for Scala array");
+
+    require_jvm();
+
+    /* Create a local frame for references to Scala objects. */
+    if ((*jenv)->PushLocalFrame(jenv, 16))
+	oom();
+
+    /* Look for class Query, static boolean call(byte[], int[]) */
+    cQuery = (*jenv)->FindClass(jenv, "Query");
+    if (cQuery == NULL)
+	die("Query: can't find Query.class");
+    mcall = (*jenv)->GetStaticMethodID(jenv, cQuery, "call", "([B[I)Z");
+    if (mcall == NULL)
+	die("Query: missing call() method");
+
+    /*
+     * Make arguments to Query.call().  We can't pass data[] and
+     * length[] to Scala, so we make new Scala arrays jdata[] and
+     * jlength[].
+     */
+    jdata = (*jenv)->NewByteArray(jenv, (jsize)jlength0);
+    if (jdata == NULL)
+	oom();
+    jlength = (*jenv)->NewIntArray(jenv, 1);
+    if (jlength == NULL)
+	oom();
+
+    /* Set jlength[0] = length[0]. */
+    (*jenv)->SetIntArrayRegion(jenv, jlength, 0, 1, &jlength0);
+    except();
+
+    /*
+     * Call our Scala method.
+     */
+    result = (*jenv)->CallStaticBooleanMethod
+	(jenv, cQuery, mcall, jdata, jlength);
+    except();
+
+    /*
+     * Set length[0] = jlength[0].
+     * Copy length[0] bytes from jdata[] to data[].
+     */
+    (*jenv)->GetIntArrayRegion(jenv, jlength, 0, 1, &jlength0);
+    except();
+    length[0] = (size_t)jlength0;
+    (*jenv)->GetByteArrayRegion
+	(jenv, jdata, 0, (jsize)jlength0, (jbyte *)data);
+
+    /* Drop our local frame and its references. */
+    (*jenv)->PopLocalFrame(jenv, NULL);
+
+    return (int)result;
+}

Task/Use-another-language-to-call-a-function/Scala/use-another-language-to-call-a-function-3.scala

@@ -0,0 +1,22 @@
+# Makefile
+
+# Edit these lines to match your JDK.
+JAVA_HOME = /Library/Java/Home
+CPPFLAGS = -I$(JAVA_HOME)/include
+LIBS = -framework JavaVM
+JAVAC = $(JAVA_HOME)/bin/javac
+CC = cc
+
+all: calljava Query.class
+
+calljava: main.o query-jni.o
+	$(CC) -o calljava main.o query-jni.o $(LIBS)
+
+.SUFFIXES: .c .class .java .o
+.c.o:
+	$(CC) $(CPPFLAGS) -c $<
+.java.class:
+	$(JAVAC) $<
+
+clean:
+	rm -f calljava main.o query-jni.o Query.class