content: # Copyright (c) Meta Platforms, Inc. and affiliates.
  #
  # This source code is licensed under the Apache License, Version 2.0
  # found in the LICENSE file in the root directory of this source tree.
  
  import itertools
  import math
  
  import torch
  import torch.nn as nn
  import torch.nn.functional as F
  
  
  _DINOV2_BASE_URL = "https://dl.fbaipublicfiles.com/dinov2"
  
  
  def _make_dinov2_model_name(arch_name: str, patch_size: int, num_register_tokens: int = 0) -> str:
      compact_arch_name = arch_name.replace("_", "")[:4]
      registers_suffix = f"_reg{num_register_tokens}" if num_register_tokens else ""
      return f"dinov2_{compact_arch_name}{patch_size}{registers_suffix}"
  
  
  class CenterPadding(nn.Module):
      def __init__(self, multiple):
          super().__init__()
          self.multiple = multiple
  
      def _get_pad(self, size):
          new_size = math.ceil(size / self.multiple) * self.multiple
          pad_size = new_size - size
          pad_size_left = pad_size // 2
          pad_size_right = pad_size - pad_size_left
          return pad_size_left, pad_size_right
  
      @torch.inference_mode()
      def forward(self, x):
          pads = list(itertools.chain.from_iterable(self._get_pad(m) for m in x.shape[:1:-1]))
          output = F.pad(x, pads)
          return output
  