mirror of https://gerrit.osmocom.org/osmo-tetra
60 lines
1.7 KiB
C
60 lines
1.7 KiB
C
/* Tetra block interleaver, according to ETSI EN 300 392-2 V3.2.1 (2007-09) */
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/* This converts from type type-3 bits into type-4 bits (and vice versa) */
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/* (C) 2011 by Harald Welte <laforge@gnumonks.org>
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <stdint.h>
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include <osmocore/utils.h>
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#include <tetra_common.h>
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#include <lower_mac/tetra_interleave.h>
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/* Section 8.2.4.1 Block interleaving for phase modulation */
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static uint32_t block_interl_func(uint32_t K, uint32_t a, uint32_t i)
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{
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return (1 + ( (a * i) % K));
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}
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void block_interleave(uint32_t K, uint32_t a, const uint8_t *in, uint8_t *out)
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{
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int i;
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for (i = 1; i <= K; i++) {
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uint32_t k = block_interl_func(K, a, i);
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DEBUGP("interl: i=%u, k=%u\n", i, k);
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out[k-1] = in[i-1];
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}
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}
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void block_deinterleave(uint32_t K, uint32_t a, const uint8_t *in, uint8_t *out)
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{
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int i;
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for (i = 1; i <= K; i++) {
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uint32_t k = block_interl_func(K, a, i);
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DEBUGP("deinterl: i=%u, k=%u\n", i, k);
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out[i-1] = in[k-1];
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}
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}
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