private static Bitmap decodeStream(MarkEnforcingInputStream is, RecyclableBufferedInputStream bufferedStream,
            BitmapFactory.Options options) {
         if (options.inJustDecodeBounds) {
             // This is large, but jpeg headers are not size bounded so we need something large enough to minimize
             // the possibility of not being able to fit enough of the header in the buffer to get the image size so
             // that we don't fail to load images. The BufferedInputStream will create a new buffer of 2x the
             // original size each time we use up the buffer space without passing the mark so this is a maximum
             // bound on the buffer size, not a default. Most of the time we won't go past our pre-allocated 16kb.
             is.mark(MARK_POSITION);
         } else {
             // Once we've read the image header, we no longer need to allow the buffer to expand in size. To avoid
             // unnecessary allocations reading image data, we fix the mark limit so that it is no larger than our
             // current buffer size here. See issue #225.
             bufferedStream.fixMarkLimit();
         }

        final Bitmap result = BitmapFactory.decodeStream(is, null, options);

        try {
            if (options.inJustDecodeBounds) {
                is.reset();
            }
        } catch (IOException e) {
            if (Log.isLoggable(TAG, Log.ERROR)) {
                Log.e(TAG, "Exception loading inDecodeBounds=" + options.inJustDecodeBounds
                        + " sample=" + options.inSampleSize, e);
            }
        }

        return result;
    }
A method for getting the dimensions of an image from the given InputStream.

@param is The InputStream representing the image.
@param options The options to pass to
         {@link BitmapFactory#decodeStream(InputStream, android.graphics.Rect,
             BitmapFactory.Options)}.
@return an array containing the dimensions of the image in the form {width, height}.
core/src/main/java/com/bumptech/glide/load/resource/bitmap/Downsampler.java