Make Blob.getData return a byte[] instead of a String.

Blob IS a `char[]`. C++ allow a char[] to be stored in a string but in
java, a String is associated to a encoding.
Content in a Blob may have no encoding so we cannot convert to a string.

Fix the test part.

lib/src/main/cpp/libzim/blob.cpp

@@ -35,7 +35,7 @@
 
 DISPOSE
 
-METHOD0(jstring, getData) {
+METHOD0(jbyteArray, getData) {
-  return TO_JNI(std::string(*THIS));
+  return cArray2jni(THIS->data(), THIS->size(), env);
 }
 GETTER(jlong, size)

lib/src/main/cpp/utils.h

@@ -199,6 +199,15 @@ template<> struct JTypeArray<bool>{
     env->SetBooleanArrayRegion(array, 0, length, reinterpret_cast<const jboolean*>(data));
   }
 };
+template<> struct JTypeArray<char>{
+  typedef jbyteArray type_t;
+  static jbyteArray createArray(JNIEnv* env, size_t length) {
+    return env->NewByteArray(length);
+  }
+  static void setArray(JNIEnv* env, jbyteArray array, const char* data, size_t length) {
+    env->SetByteArrayRegion(array, 0, length, reinterpret_cast<const signed char*>(data));
+  }
+};
 template<> struct JTypeArray<int32_t>{
   typedef jintArray type_t;
   static jintArray createArray(JNIEnv* env, size_t length) {
@@ -278,6 +287,14 @@ inline typename JTypeArray<U>::type_t c2jni(const std::set<U>& val, JNIEnv* env)
   return c2jni(temp, env);
 }
 
+template<typename U>
+inline typename JTypeArray<U>::type_t cArray2jni(const U* data, size_t length, JNIEnv* env)
+{
+  auto array = JTypeArray<U>::createArray(env, length);
+  JTypeArray<U>::setArray(env, array, data, length);
+  return array;
+}
+
 #define TO_JNI(VAL) c2jni(VAL, env)
 
 

lib/src/main/java/org/kiwix/libzim/Blob.java

@@ -23,7 +23,7 @@ import org.kiwix.libzim.Blob;
 
 public class Blob
 {
-  public native String getData();
+  public native byte[] getData();
   public native long size();
 
 

lib/src/test/test.java

@@ -44,10 +44,8 @@ public class test {
         return new String(getFileContent(path));
     }
 
-    @Test
+    private void testArchive(Archive archive)
-    public void testArchive()
+        throws IOException {
-            throws JNIKiwixException, IOException, ZimFileFormatException {
-        Archive archive = new Archive("small.zim");
         // test the zim file main page title
         assertEquals("Test ZIM file", archive.getMainEntry().getTitle());
         // test zim file size
@@ -55,21 +53,29 @@ public class test {
         // test zim file main url
         assertEquals("A/main.html", archive.getMainEntry().getPath());
         // test zim file content
-        String s = getTextFileContent("small_zimfile_data/main.html");
+        byte[] mainData = getFileContent("small_zimfile_data/main.html");
-        String c = archive.getEntryByPath("A/main.html").getItem(true).getData().getData();
+        byte[] inZimMainData = archive.getEntryByPath("A/main.html").getItem(true).getData().getData();
-        assertEquals(s, c);
+        assert(Arrays.equals(mainData, inZimMainData));
 
         // test zim file icon
-        byte[] faviconData = getFileContent("small_zimfile_data/favicon.png");
         assertEquals(true, archive.hasIllustration(48));
+        byte[] faviconData = getFileContent("small_zimfile_data/favicon.png");
         Item item = archive.getIllustrationItem(48);
         assertEquals(faviconData.length, item.getSize());
+        assert(Arrays.equals(faviconData, item.getData().getData()));
 
-        DirectAccessInfo dai = archive.getEntryByPath("I/favicon.png").getItem(true).getDirectAccessInformation();
+        // Checking direct access information
+        DirectAccessInfo dai = item.getDirectAccessInformation();
         assertNotEquals("", dai.filename);
-        c = new String(getFileContentPartial(dai.filename, (int) dai.offset, faviconData.length));
+        byte[] readData = getFileContentPartial(dai.filename, (int) dai.offset, (int) item.getSize());
-        assertEquals(new String(faviconData), c);
+        assert(Arrays.equals(faviconData, readData));
+   }
 
+    @Test
+    public void testArchiveDirect()
+            throws JNIKiwixException, IOException, ZimFileFormatException {
+        Archive archive = new Archive("small.zim");
+        testArchive(archive);
         archive.dispose();
 
         // test reader with invalid zim file
@@ -87,28 +93,7 @@ public class test {
             throws JNIKiwixException, IOException, ZimFileFormatException {
         FileInputStream fis = new FileInputStream("small.zim");
         Archive archive = new Archive(fis.getFD());
-        // test the zim file main page title
+        testArchive(archive);
-        assertEquals("Test ZIM file", archive.getMainEntry().getTitle());
-        // test zim file size
-        assertEquals(4070, archive.getFilesize()); // The file size is in KiB
-        // test zim file main url
-        assertEquals("A/main.html", archive.getMainEntry().getPath());
-        // test zim file content
-        String s = getTextFileContent("small_zimfile_data/main.html");
-        String c = archive.getEntryByPath("A/main.html").getItem(true).getData().getData();
-        assertEquals(s, c);
-
-        // test zim file icon
-        byte[] faviconData = getFileContent("small_zimfile_data/favicon.png");
-        assertEquals(true, archive.hasIllustration(48));
-        Item item = archive.getIllustrationItem(48);
-        assertEquals(faviconData.length, item.getSize());
-
-        DirectAccessInfo dai = archive.getEntryByPath("I/favicon.png").getItem(true).getDirectAccessInformation();
-        assertNotEquals("", dai.filename);
-        c = new String(getFileContentPartial(dai.filename, (int) dai.offset, faviconData.length));
-        assertEquals(new String(faviconData), c);
-
         archive.dispose();
     }
 
@@ -118,29 +103,7 @@ public class test {
         File plainArchive = new File("small.zim");
         FileInputStream fis = new FileInputStream("small.zim.embedded");
         Archive archive = new Archive(fis.getFD(), 8, plainArchive.length());
-        // test the zim file main page title
+        testArchive(archive);
-        assertEquals("Test ZIM file", archive.getMainEntry().getTitle());
-        // test zim file size
-        assertEquals(4070, archive.getFilesize()); // The file size is in KiB
-        // test zim file main url
-        assertEquals("A/main.html", archive.getMainEntry().getPath());
-        // test zim file content
-        String s = getTextFileContent("small_zimfile_data/main.html");
-        String c = archive.getEntryByPath("A/main.html").getItem(true).getData().getData();
-        assertEquals(s, c);
-
-        // test zim file icon
-        byte[] faviconData = getFileContent("small_zimfile_data/favicon.png");
-        assertEquals(true, archive.hasIllustration(48));
-        Item item = archive.getIllustrationItem(48);
-        assertEquals(faviconData.length, item.getSize());
-        assertEquals(new String(faviconData), item.getData().getData());
-
-        DirectAccessInfo dai = archive.getEntryByPath("I/favicon.png").getItem(true).getDirectAccessInformation();
-        assertNotEquals("", dai.filename);
-        c = new String(getFileContentPartial(dai.filename, (int) dai.offset, faviconData.length));
-        assertEquals(new String(faviconData), c);
-
         archive.dispose();
     }