Compare the asset apk with extracted apk by their size

Android/DevSample/small/src/main/java/net/wequick/small/Bundle.java

@@ -462,27 +462,16 @@ private void extractBundle(String assetName, File outFile) throws IOException {
  InputStream in = Small.getContext().getAssets().open(assetName);
  FileOutputStream out;
  if (outFile.exists()) {
- // Compare the zip time to see if needs re-extract.
- // @see https://en.wikipedia.org/wiki/Zip_(file_format)
+ // Compare the two input steams to see if needs re-extract.
  FileInputStream fin = new FileInputStream(outFile);
- final int headerSizeBeforeTime = 10;
- final int headerSizeOfTime = 4;
- byte[] inHeader = new byte[headerSizeBeforeTime];
- byte[] inTime = new byte[headerSizeOfTime];
- byte[] outTime = new byte[headerSizeOfTime];
- in.read(inHeader);
- in.read(inTime);
- fin.skip(headerSizeBeforeTime);
- fin.read(outTime);
- fin.close();
- if (Arrays.equals(inTime, outTime)) {
- in.close();
+ int inSize = in.available();
+ long outSize = fin.available();
+ if (inSize == outSize) {
+ // FIXME: What about the size is same but the content is different?
  return; // UP-TO-DATE
  }
 
  out = new FileOutputStream(outFile);
- out.write(inHeader, 0, headerSizeBeforeTime);
- out.write(inTime, 0, headerSizeOfTime);
  } else {
  out = new FileOutputStream(outFile);
  }