Merge "floss: Support 128-bit UUID to shortest bytes array conversion" (f847c040) · Commits · e / os / android_packages_modules_Bluetooth

system/gd/rust/linux/stack/src/uuid.rs

+59 −0

Original line number	Diff line number	Diff line
		@@ -72,6 +72,10 @@ pub enum Profile {
		CoordinatedSet,
		}

		// Unsigned integer representation of UUIDs.
		pub const BASE_UUID_NUM: u128 = 0x0000000000001000800000805f9b34fbu128;
		pub const BASE_UUID_MASK: u128 = !(0xffffffffu128 << 96);

		/// Wraps a reference of Uuid128Bit, which is the raw array of bytes of UUID.
		/// This is useful in implementing standard Rust traits which can't be implemented directly on
		/// built-in types (Rust's Orphan Rule).
		@@ -92,6 +96,14 @@ impl<'a> Display for KnownUuidWrapper<'a> {
		}
		}

		/// Represents binary encoding of UUID in big-endian.
		#[derive(Debug)]
		pub enum UuidBytes {
		Uuid16Bit([u8; 2]),
		Uuid32Bit([u8; 4]),
		Uuid128Bit([u8; 16]),
		}

		pub struct UuidHelper {
		/// A list of enabled profiles on the system. These may be modified by policy.
		pub enabled_profiles: HashSet<Profile>,
		@@ -214,6 +226,31 @@ impl UuidHelper {

		Some(uuid)
		}

		/// Parses an 128-bit UUID into a byte array of shortest representation.
		pub fn get_shortest_bytes(uuid: &Uuid128Bit) -> UuidBytes {
		if UuidHelper::in_16bit_uuid_range(uuid) {
		return UuidBytes::Uuid16Bit([uuid[2], uuid[3]]);
		} else if UuidHelper::in_32bit_uuid_range(uuid) {
		return UuidBytes::Uuid32Bit([uuid[0], uuid[1], uuid[2], uuid[3]]);
		} else {
		return UuidBytes::Uuid128Bit(*uuid);
		}
		}

		/// Checks whether the UUID value is in the 16-bit Bluetooth UUID range.
		fn in_16bit_uuid_range(uuid: &Uuid128Bit) -> bool {
		if !UuidHelper::in_32bit_uuid_range(uuid) {
		return false;
		}
		uuid[0] == 0 && uuid[1] == 0
		}

		/// Checks whether the UUID value is in the 32-bit Bluetooth UUID range.
		fn in_32bit_uuid_range(uuid: &Uuid128Bit) -> bool {
		let num = u128::from_be_bytes(*uuid);
		(num & BASE_UUID_MASK) == BASE_UUID_NUM
		}
		}

		// Temporary util that covers only basic string conversion.
		@@ -255,4 +292,26 @@ mod tests {
		});
		}
		}

		#[test]
		fn test_get_shortest_bytes() {
		let uuid_16 = UuidHelper::from_string("0000fef3-0000-1000-8000-00805f9b34fb").unwrap();
		assert!(matches!(
		UuidHelper::get_shortest_bytes(&uuid_16),
		UuidBytes::Uuid16Bit([0xfe, 0xf3])
		));

		let uuid_32 = UuidHelper::from_string("00112233-0000-1000-8000-00805f9b34fb").unwrap();
		assert!(matches!(
		UuidHelper::get_shortest_bytes(&uuid_32),
		UuidBytes::Uuid32Bit([0x00, 0x11, 0x22, 0x33])
		));

		let uuid_128 = UuidHelper::from_string("00112233-4455-6677-8899-aabbccddeeff").unwrap();
		let exp_bytes: Vec<u8> = (0..16).map(\|d\| (d << 4) + d).collect();
		assert!(matches!(
		UuidHelper::get_shortest_bytes(&uuid_128),
		UuidBytes::Uuid128Bit(exp_bytes)
		));
		}
		}