1 // Copyright 2022 The Pigweed Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
5 // the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
13 // the License.
14 #pragma once
15
16 #include <cstdint>
17
18 namespace pw::bluetooth::internal {
19
20 // Parse a hexadecimal character to a 0-15 number. If the hex char is invalid
21 // returns 0x100.
HexToNibble(char hex)22 constexpr uint16_t HexToNibble(char hex) {
23 if (hex >= '0' && hex <= '9') {
24 return hex - '0';
25 }
26 if (hex >= 'A' && hex <= 'F') {
27 return hex - 'A' + 10;
28 }
29 if (hex >= 'a' && hex <= 'f') {
30 return hex - 'a' + 10;
31 }
32 return 0x100;
33 }
34
35 // Convert a nibble (0 to 15 value) to its lowercase hexadecimal representation.
NibbleToHex(uint8_t value)36 constexpr char NibbleToHex(uint8_t value) {
37 if (value < 10) {
38 return '0' + value;
39 }
40 if (value < 16) {
41 return 'a' + value - 10;
42 }
43 return '?';
44 }
45
46 } // namespace pw::bluetooth::internal
47