add ZipExtractor class

Co-authored-by: gabriel <gabriel>

src/pandroid/app/src/main/java/com/panda3ds/pandroid/utils/ZipExtractor.java

@@ -0,0 +1,63 @@
+package com.panda3ds.pandroid.utils;
+
+import android.net.Uri;
+
+import java.io.FileOutputStream;
+import java.io.OutputStream;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+
+public class ZipExtractor {
+
+
+    public static void extract(String zipFile, String outputFolder, String outputName) throws Exception {
+        String path = outputFolder;
+        if (FileUtils.exists(path+"/"+outputName)) {
+            throw new IllegalArgumentException("File already exists in output location");
+        }
+
+        byte[] buffer = new byte[1024*256];
+        int bufferLen = 0;
+
+        ZipInputStream in = new ZipInputStream(FileUtils.getInputStream(zipFile));
+        ZipEntry entry = in.getNextEntry();
+        while (entry != null) {
+            if (!entry.isDirectory()) {
+                String[] dir = entry.getName().split("/");
+                String parent;
+                {
+                    StringBuilder builder = new StringBuilder();
+                    for (int i = dir[0].length() == 0 ? 1 : 0; i < dir.length - 1; i++) {
+                        builder.append(dir[i]).append("/");
+                    }
+                    parent = builder.toString();
+                }
+                if (parent.length() > 0) {
+                    mkdirs(path, parent);
+                }
+                if (parent.length() > 0) {
+                    parent = "/" + parent;
+                }
+                String name = dir[dir.length-1];
+                FileUtils.createFile(path+parent, name);
+                OutputStream out = FileUtils.getOutputStream(path+parent+"/"+name);
+                while ((bufferLen = in.read(buffer)) != -1) {
+                    out.write(buffer, 0, bufferLen);
+                }
+                out.flush();
+                out.close();
+            }
+            entry = in.getNextEntry();
+        }
+        in.close();
+    }
+
+    private static void mkdirs(String path, String subs) {
+        for (String segment: subs.split("/")) {
+            if (!FileUtils.exists(path+"/"+segment)) {
+                FileUtils.createDir(path, segment);
+            }
+            path = path + "/"+segment;
+        }
+    }
+}