# General - How To - Recipes { #general-how-to-recipes }

Here are several pointers to other places in the docs, for general or frequent questions.

## Filter Data - Security { #filter-data-security }

To ensure that you don't return more data than you should, read the docs for [Tutorial - Response Model - Return Type](../tutorial/response-model.md).

          // Skip the elements larger than the partition.
          do {
            high--;
          } while (array[high] > partition);
          if (high < low) {
            break; // Pointers crossed. Partitioning complete.
          }
          swap(array, low, high); // End of innermost loop.
        }
        array[from + 1] = array[high]; // Insert partitioning element.
        array[high] = partition;

    string key(v2_reader_->key());
    (*var_to_shape_map)[key] = TensorShape(entry.shape());
    (*var_to_data_type_map)[key] = DataType(entry.dtype());
  }
  // The returned pointers are owned by the caller.
  return std::make_pair(std::move(var_to_shape_map),
                        std::move(var_to_data_type_map));
}

}  // namespace checkpoint

          // Skip the elements larger than the partition.
          do {
            high--;
          } while (array[high] > partition);
          if (high < low) {
            break; // Pointers crossed. Partitioning complete.
          }
          swap(array, low, high); // End of innermost loop.
        }
        array[from + 1] = array[high]; // Insert partitioning element.
        array[high] = partition;

    // drop the contract on the method that enforces this queue like behavior since depending on it
    // is likely to be a bug anyway.

    // N.B. All writes to the list and the next pointers must have happened before the above
    // synchronized block, so we can iterate the list without the lock held here.
    RunnableExecutorPair reversedList = null;
    while (list != null) {

    setSucceeds(predecessor, size);
    setSucceeds(size, successor);
    size++;
    modCount++;
    return null;
  }

  /**
   * Updates the pointers of the insertion order linked list so that {@code next} follows {@code
   * prev}. {@code ENDPOINT} represents either the first or last entry in the entire map (as
   * appropriate).
   */

* Why is this change done? What's the use case?
* For user-facing features, what will the API look like?
* What test cases should it have? What could go wrong?
* How will it roughly be implemented? We'll happily provide code pointers to save you time.

We may ask you to answer these questions directly in the GitHub issue or (for large changes) in a shared Google Doc.

// const declaration. It is zero-indexed.
const iota = 0 // Untyped int.

// nil is a predeclared identifier representing the zero value for a
// pointer, channel, func, interface, map, or slice type.
var nil Type // Type must be a pointer, channel, func, interface, map, or slice type

// Type is here for the purposes of documentation only. It is a stand-in

}

// Cap returns the capacity of the cache
func (c *LRU[K, V]) Cap() int {
	return c.size
}

// Entry is an LRU Entry
type Entry[K comparable, V any] struct {
	// Next and previous pointers in the doubly-linked list of elements.
	// To simplify the implementation, internally a list l is implemented
	// as a ring, such that &l.root is both the next element of the last

		if b.Available() == 0 {
			err = b.Flush()
		} else {
			err = nil
		}
	}
	return n, err
}

// buffered input and output

// ReadWriter stores pointers to a [Reader] and a [Writer].
// It implements [io.ReadWriter].
type ReadWriter struct {
	*Reader
	*Writer
}

// NewReadWriter allocates a new [ReadWriter] that dispatches to r and w.