honest-rivers-deny

Added new containsBytes and getConstantCodec helpers

The containsBytes helper checks if a Uint8Array contains another Uint8Array at a given offset.

containsBytes(new Uint8Array([1, 2, 3, 4]), new Uint8Array([2, 3]), 1); // true
containsBytes(new Uint8Array([1, 2, 3, 4]), new Uint8Array([2, 3]), 2); // false

The getConstantCodec function accepts any Uint8Array and returns a Codec<void>. When encoding, it will set the provided Uint8Array as-is. When decoding, it will assert that the next bytes contain the provided Uint8Array and move the offset forward.

const codec = getConstantCodec(new Uint8Array([1, 2, 3]));

codec.encode(undefined); // 0x010203
codec.decode(new Uint8Array([1, 2, 3])); // undefined
codec.decode(new Uint8Array([1, 2, 4])); // Throws an error.