74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
/*
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* (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de>
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* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
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* (C) 2009 by Harald Welte <laforge@gnumonks.org>
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*
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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 General Public License as published by
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* the Free Software Foundation; either version 2 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 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 along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <openbsc/gsm_utils.h>
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#include <stdlib.h>
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#include <string.h>
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/* GSM 03.38 6.2.1 Charachter packing */
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int gsm_7bit_decode(char *text, const u_int8_t *user_data, u_int8_t length)
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{
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u_int8_t d_off = 0, b_off = 0;
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u_int8_t i;
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for (i=0;i<length;i++) {
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text[i] = ((user_data[d_off] + (user_data[d_off+1]<<8)) & (0x7f<<b_off))>>b_off;
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b_off += 7;
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if (b_off >= 8) {
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d_off += 1;
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b_off -= 8;
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}
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}
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text[i] = '\0';
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return 0;
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}
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/* GSM 03.38 6.2.1 Charachter packing */
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int gsm_7bit_encode(u_int8_t *result, const char *data)
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{
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int i;
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u_int8_t d_off = 0, b_off = 0;
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const int length = strlen(data);
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int out_length = (length * 8)/7;
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memset(result, 0, out_length);
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for (i = 0; i < length; ++i) {
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u_int8_t first = (data[i] & 0x7f) << b_off;
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u_int8_t second = (data[i] & 0x7f) >> (8 - b_off);
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result[d_off] |= first;
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if (second != 0)
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result[d_off + 1] = second;
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b_off += 7;
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if (b_off >= 8) {
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d_off += 1;
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b_off -= 8;
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}
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}
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return out_length;
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}
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