mirror of https://gerrit.osmocom.org/osmo-tetra
118 lines
2.2 KiB
C
118 lines
2.2 KiB
C
/* Convert floating point symbols in the range +3/-3 to hard bits,
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* in the 1-bit-per-byte format */
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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 <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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static int process_sym_fl(float offset, float fl)
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{
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int ret;
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fl += offset;
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/* very simplistic scheme */
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if (fl > 2)
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ret = 3;
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else if (fl > 0)
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ret = 1;
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else if (fl < -2)
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ret = -3;
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else
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ret = -1;
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return ret;
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}
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static void sym_int2bits(int sym, uint8_t *ret)
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{
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switch (sym) {
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case -3:
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ret[0] = 1;
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ret[1] = 1;
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break;
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case 1:
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ret[0] = 0;
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ret[1] = 0;
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break;
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//case -1:
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case 3:
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ret[0] = 0;
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ret[1] = 1;
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break;
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//case 3:
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case -1:
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ret[0] = 1;
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ret[1] = 0;
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break;
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}
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}
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int main(int argc, char **argv)
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{
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int fd, fd_out;
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if (argc < 3) {
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fprintf(stderr, "Usage: %s <infile> <outfile>\n", argv[0]);
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exit(2);
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}
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fd = open(argv[1], O_RDONLY);
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if (fd < 0) {
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perror("open infile");
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exit(1);
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}
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fd_out = creat(argv[2], 0660);
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if (fd_out < 0) {
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perror("open outfile");
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exit(1);
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}
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while (1) {
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int rc;
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float fl;
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uint8_t bits[2];
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rc = read(fd, &fl, sizeof(fl));
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if (rc < 0) {
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perror("read");
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exit(1);
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} else if (rc == 0)
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break;
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rc = process_sym_fl(0.3f, fl);
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sym_int2bits(rc, bits);
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//printf("%2d %1u %1u %f\n", rc, bits[0], bits[1], fl);
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//printf("%1u%1u", bits[0], bits[1]);
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rc = write(fd_out, bits, 2);
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if (rc < 0) {
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perror("write");
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exit(1);
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} else if (rc == 0)
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break;
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}
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exit(0);
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}
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