convert between float arrays and byte arrays

Encoding.java

package randomindexing;

/* Helpers for encoding various primitive arrays as byte arrays.
   (Why this isn't in the stdlib I have no idea! feel free to replace
   with some existing library implementation...)

   All encodings use little-endian byte order.
   I benchmarked using
   ByteBuffer.wrap(b).order(LITTLE_ENDIAN).asFloatBuffer().get(f),
   but it's around 3 times slower even on big input.
*/
public class Encoding {
  public static void floatsToBytes(float[] floats, byte[] bytes) {
    assert floats.length * 4 == bytes.length;
    for (int i = 0; i < floats.length; i++) {
      int x = Float.floatToRawIntBits(floats[i]);
      bytes[i*4] = (byte) (x & 0xff);
      bytes[i*4+1] = (byte) ((x >>> 8) & 0xff);
      bytes[i*4+2] = (byte) ((x >>> 16) & 0xff);
      bytes[i*4+3] = (byte) (x >>> 24);
    }
  }

  public static byte[] floatsToBytes(float[] floats) {
    byte[] bytes = new byte[floats.length * 4];
    floatsToBytes(floats, bytes);
    return bytes;
  }

  public static void bytesToFloats(byte[] bytes, float[] floats) {
    assert floats.length * 4 == bytes.length;
    for (int i = 0; i < floats.length; i++) {
      int x = bytes[i*4] & 0xff;
      x += (bytes[i*4+1] & 0xff) << 8;
      x += (bytes[i*4+2] & 0xff) << 16;
      x += (bytes[i*4+3] & 0xff) << 24;
      floats[i] = Float.intBitsToFloat(x);
    }
  }

  public static float[] bytesToFloats(byte[] bytes) {
    float[] floats = new float[bytes.length / 4];
    bytesToFloats(bytes, floats);
    return floats;
  }
}