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author | Matthias P. Braendli <matthias.braendli@mpb.li> | 2014-11-09 11:33:11 +0100 |
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committer | Matthias P. Braendli <matthias.braendli@mpb.li> | 2014-11-09 11:33:11 +0100 |
commit | 639951285591ab6e8d1158e336a3f6c19477cc4f (patch) | |
tree | 40c6090f564539cd2bb201b85e4ffa53ddd4b880 /firecode.c | |
parent | 588a749b8544afce1824d9bcda80f2c5a44524e5 (diff) | |
download | etisnoop-639951285591ab6e8d1158e336a3f6c19477cc4f.tar.gz etisnoop-639951285591ab6e8d1158e336a3f6c19477cc4f.tar.bz2 etisnoop-639951285591ab6e8d1158e336a3f6c19477cc4f.zip |
ETISnoop search for firecode
Diffstat (limited to 'firecode.c')
-rw-r--r-- | firecode.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/firecode.c b/firecode.c new file mode 100644 index 0000000..fd13dec --- /dev/null +++ b/firecode.c @@ -0,0 +1,50 @@ +/* + Copyright (C) 2014 Matthias P. Braendli (http://www.opendigitalradio.org) + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + + firecode.c + Implement a FireCode CRC calculator + + Authors: + Matthias P. Braendli <matthias@mpb.li> +*/ + +#include "firecode.h" + +uint16_t firecode_crc(uint8_t* buf, size_t size) +{ + int crc; + int gen_poly; + + crc = 0x0000; + gen_poly = 0x782F; // 0111 1000 0010 1111 (16, 14, 13, 12, 11, 5, 3, 2, 1, 0) + + for (int len = 0; len < size; len++) { + for (int i = 0x80; i != 0; i >>= 1) { + if ((crc & 0x8000) != 0) { + crc = (crc << 1) ^ gen_poly; + } + else { + crc = crc << 1; + } + if ((buf[len] & i) != 0) { + crc ^= gen_poly; + } + } + } + + return crc & 0xFFFF; +} + |