| /* |
| * |
| * Copyright (c) 2020 Project CHIP Authors |
| * Copyright (c) 2015-2017 Nest Labs, Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #if !__has_feature(objc_arc) |
| #error This file must be compiled with ARC. Use -fobjc-arc flag (or convert project to ARC). |
| #endif |
| |
| #import "UUIDHelper.h" |
| |
| @implementation UUIDHelper |
| |
| + (CBUUID *)GetShortestServiceUUID:(const chip::Ble::ChipBleUUID *)svcId |
| { |
| // shorten the 16-byte UUID reported by BLE Layer to shortest possible, 2 or 4 bytes |
| // this is the BLE Service UUID Base. If a 16-byte service UUID partially matches with these 12 bytes, |
| // it can be shortened to 2 or 4 bytes. |
| static const uint8_t bleBaseUUID[12] = { 0x00, 0x00, 0x10, 0x00, 0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB }; |
| if (0 == memcmp(svcId->bytes + 4, bleBaseUUID, sizeof(bleBaseUUID))) { |
| // okay, let's try to shorten it |
| if ((0 == svcId->bytes[0]) && (0 == svcId->bytes[1])) { |
| // the highest 2 bytes are both 0, so we just need 2 bytes |
| return [CBUUID UUIDWithData:[NSData dataWithBytes:(svcId->bytes + 2) length:2]]; |
| } else { |
| // we need to use 4 bytes |
| return [CBUUID UUIDWithData:[NSData dataWithBytes:svcId->bytes length:4]]; |
| } |
| } else { |
| // it cannot be shortened as it doesn't match with the BLE Service UUID Base |
| return [CBUUID UUIDWithData:[NSData dataWithBytes:svcId->bytes length:16]]; |
| } |
| } |
| @end |
