static bool areEqual(List a, Object b) {
  if (a === b) return true;
  if (!(b is List)) return false;
  int length = a.length;
  if (length != b.length) return false;

  for (int i = 0; i < length; i++) {
    if (a[i] !== b[i]) return false;
  }
  return true;
}

static void copy(List src, int srcStart,
                 List dst, int dstStart, int count) {
  if (srcStart === null) srcStart = 0;
  if (dstStart === null) dstStart = 0;

  if (srcStart < dstStart) {
    for (int i = srcStart + count - 1, j = dstStart + count - 1;
         i >= srcStart; i--, j--) {
      dst[j] = src[i];
    }
  } else {
    for (int i = srcStart, j = dstStart; i < srcStart + count; i++, j++) {
      dst[j] = src[i];
    }
  }
}

Returns the index in the list a of the given element, starting the search at index startIndex to endIndex. Returns -1 if element is not found.

static int indexOf(List a,
                   Object element,
                   int startIndex,
                   int endIndex) {
  if (startIndex >= a.length) {
    return -1;
  }
  if (startIndex < 0) {
    startIndex = 0;
  }
  for (int i = startIndex; i < endIndex; i++) {
    if (a[i] == element) {
      return i;
    }
  }
  return -1;
}

Returns the last index in the list a of the given element, starting the search at index startIndex to 0. Returns -1 if element is not found.

static int lastIndexOf(List a, Object element, int startIndex) {
  if (startIndex < 0) {
    return -1;
  }
  if (startIndex >= a.length) {
    startIndex = a.length - 1;
  }
  for (int i = startIndex; i >= 0; i--) {
    if (a[i] == element) {
      return i;
    }
  }
  return -1;
}

static void rangeCheck(List a, int start, int length) {
  if (length < 0) {
    throw new IllegalArgumentException("negative length $length");
  }
  if (start < 0 || start >= a.length) {
    String message = "$start must be in the range [0..${a.length})"; 
    throw new IndexOutOfRangeException(message);
  }
  if (start + length > a.length) {
    String message = "$start + $length must be in the range [0..${a.length})";
    throw new IndexOutOfRangeException(message);
  }
}