pragma solidity >=0.6.12;

// Author:	Louis Holbrook <dev@holbrook.no> 0826EDA1702D1E87C6E2875121D2E7BB88C2A746
// SPDX-License-Identifier:	AGPL-3.0-or-later
// File-version: 1

interface IDigest {
	// Returns the default digest encoding used by the contract instance.
	function defaultDigestEncoding() external view returns (uint256 _encoding);

	// Check if the given encoding has been implemented in the contract instance.
	function haveDigestEncoding(uint256 _codec) external view returns(bool);

	// Verify and encode the given digest for a specific hashing algorithm.
	// Returns a zero-length byte array if digest is invalid.
	// Must succeed if called with the defaultDigestEncoding and a valid digest.
	function encodeDigest(bytes memory _data, uint256 _encoding) external view returns (bytes memory);

	// Encodes the digest using the default digest encoding.
	// Returns a zero-length byte array if digest is invalid.
	// Must succeed with a valid digest.
	function encodeDigest(bytes memory _data) external view returns (bytes memory);
}