270a22e06a
Also be smarter about error correction, avoiding ambiguous cases when --aggressive is specified.
40 lines
1.4 KiB
C
40 lines
1.4 KiB
C
// Part of dump1090, a Mode S message decoder for RTLSDR devices.
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//
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// crc.h: Mode S checksum prototypes.
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//
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// Copyright (c) 2014,2015 Oliver Jowett <oliver@mutability.co.uk>
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//
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// This file is free software: you may copy, redistribute and/or modify it
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// under the terms of the GNU General Public License as published by the
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// Free Software Foundation, either version 2 of the License, or (at your
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// option) any later version.
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//
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// This file is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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#ifndef DUMP1090_CRC_H
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#define DUMP1090_CRC_H
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#include <stdint.h>
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// Global max for fixable bit erros
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#define MODES_MAX_BITERRORS 2
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struct errorinfo {
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uint32_t syndrome; // CRC syndrome
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int errors; // number of errors
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int8_t bit[MODES_MAX_BITERRORS]; // bit positions to fix (-1 = no bit)
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};
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void modesChecksumInit(int fixBits);
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uint32_t modesChecksum(uint8_t *msg, int bitlen);
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struct errorinfo *modesChecksumDiagnose(uint32_t syndrome, int bitlen);
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void modesChecksumFix(uint8_t *msg, struct errorinfo *info);
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#endif
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