xref: /aosp_15_r20/external/pigweed/pw_checksum/crc16_ccitt.cc (revision 61c4878ac05f98d0ceed94b57d316916de578985)
1*61c4878aSAndroid Build Coastguard Worker // Copyright 2020 The Pigweed Authors
2*61c4878aSAndroid Build Coastguard Worker //
3*61c4878aSAndroid Build Coastguard Worker // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4*61c4878aSAndroid Build Coastguard Worker // use this file except in compliance with the License. You may obtain a copy of
5*61c4878aSAndroid Build Coastguard Worker // the License at
6*61c4878aSAndroid Build Coastguard Worker //
7*61c4878aSAndroid Build Coastguard Worker //     https://www.apache.org/licenses/LICENSE-2.0
8*61c4878aSAndroid Build Coastguard Worker //
9*61c4878aSAndroid Build Coastguard Worker // Unless required by applicable law or agreed to in writing, software
10*61c4878aSAndroid Build Coastguard Worker // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11*61c4878aSAndroid Build Coastguard Worker // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12*61c4878aSAndroid Build Coastguard Worker // License for the specific language governing permissions and limitations under
13*61c4878aSAndroid Build Coastguard Worker // the License.
14*61c4878aSAndroid Build Coastguard Worker 
15*61c4878aSAndroid Build Coastguard Worker #include "pw_checksum/crc16_ccitt.h"
16*61c4878aSAndroid Build Coastguard Worker 
17*61c4878aSAndroid Build Coastguard Worker namespace pw::checksum {
18*61c4878aSAndroid Build Coastguard Worker namespace {
19*61c4878aSAndroid Build Coastguard Worker 
20*61c4878aSAndroid Build Coastguard Worker constexpr uint16_t kCrc16CcittTable[256]{
21*61c4878aSAndroid Build Coastguard Worker     0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
22*61c4878aSAndroid Build Coastguard Worker     0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
23*61c4878aSAndroid Build Coastguard Worker     0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
24*61c4878aSAndroid Build Coastguard Worker     0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,  // 32
25*61c4878aSAndroid Build Coastguard Worker     0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
26*61c4878aSAndroid Build Coastguard Worker     0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
27*61c4878aSAndroid Build Coastguard Worker     0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
28*61c4878aSAndroid Build Coastguard Worker     0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,  // 64
29*61c4878aSAndroid Build Coastguard Worker     0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
30*61c4878aSAndroid Build Coastguard Worker     0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
31*61c4878aSAndroid Build Coastguard Worker     0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
32*61c4878aSAndroid Build Coastguard Worker     0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,  // 96
33*61c4878aSAndroid Build Coastguard Worker     0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
34*61c4878aSAndroid Build Coastguard Worker     0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
35*61c4878aSAndroid Build Coastguard Worker     0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
36*61c4878aSAndroid Build Coastguard Worker     0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,  // 128
37*61c4878aSAndroid Build Coastguard Worker     0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
38*61c4878aSAndroid Build Coastguard Worker     0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
39*61c4878aSAndroid Build Coastguard Worker     0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
40*61c4878aSAndroid Build Coastguard Worker     0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,  // 160
41*61c4878aSAndroid Build Coastguard Worker     0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
42*61c4878aSAndroid Build Coastguard Worker     0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
43*61c4878aSAndroid Build Coastguard Worker     0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
44*61c4878aSAndroid Build Coastguard Worker     0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,  // 192
45*61c4878aSAndroid Build Coastguard Worker     0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
46*61c4878aSAndroid Build Coastguard Worker     0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
47*61c4878aSAndroid Build Coastguard Worker     0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
48*61c4878aSAndroid Build Coastguard Worker     0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,  // 224
49*61c4878aSAndroid Build Coastguard Worker     0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
50*61c4878aSAndroid Build Coastguard Worker     0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
51*61c4878aSAndroid Build Coastguard Worker     0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
52*61c4878aSAndroid Build Coastguard Worker     0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,  // 256
53*61c4878aSAndroid Build Coastguard Worker };
54*61c4878aSAndroid Build Coastguard Worker 
55*61c4878aSAndroid Build Coastguard Worker }  // namespace
56*61c4878aSAndroid Build Coastguard Worker 
pw_checksum_Crc16Ccitt(const void * data,size_t size_bytes,uint16_t value)57*61c4878aSAndroid Build Coastguard Worker extern "C" uint16_t pw_checksum_Crc16Ccitt(const void* data,
58*61c4878aSAndroid Build Coastguard Worker                                            size_t size_bytes,
59*61c4878aSAndroid Build Coastguard Worker                                            uint16_t value) {
60*61c4878aSAndroid Build Coastguard Worker   const uint8_t* const array = static_cast<const uint8_t*>(data);
61*61c4878aSAndroid Build Coastguard Worker 
62*61c4878aSAndroid Build Coastguard Worker   for (size_t i = 0; i < size_bytes; ++i) {
63*61c4878aSAndroid Build Coastguard Worker     value = kCrc16CcittTable[((value >> 8u) ^ array[i]) & 0xffu] ^
64*61c4878aSAndroid Build Coastguard Worker             static_cast<uint16_t>(value << 8u);
65*61c4878aSAndroid Build Coastguard Worker   }
66*61c4878aSAndroid Build Coastguard Worker 
67*61c4878aSAndroid Build Coastguard Worker   return value;
68*61c4878aSAndroid Build Coastguard Worker }
69*61c4878aSAndroid Build Coastguard Worker 
70*61c4878aSAndroid Build Coastguard Worker }  // namespace pw::checksum
71