| /* |
| * (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de> |
| * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org> |
| * (C) 2009 by Harald Welte <laforge@gnumonks.org> |
| * |
| * All Rights Reserved |
| * |
| * 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 2 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, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| */ |
| |
| #include <openbsc/gsm_data.h> |
| #include <openbsc/gsm_utils.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <errno.h> |
| |
| /* GSM 03.38 6.2.1 Charachter packing */ |
| int gsm_7bit_decode(char *text, const u_int8_t *user_data, u_int8_t length) |
| { |
| u_int8_t d_off = 0, b_off = 0; |
| u_int8_t i; |
| |
| for (i=0;i<length;i++) { |
| text[i] = ((user_data[d_off] + (user_data[d_off+1]<<8)) & (0x7f<<b_off))>>b_off; |
| b_off += 7; |
| if (b_off >= 8) { |
| d_off += 1; |
| b_off -= 8; |
| } |
| } |
| text[i] = '\0'; |
| return 0; |
| } |
| |
| /* GSM 03.38 6.2.1 Charachter packing */ |
| int gsm_7bit_encode(u_int8_t *result, const char *data) |
| { |
| int i; |
| u_int8_t d_off = 0, b_off = 0; |
| const int length = strlen(data); |
| int out_length = (length * 8)/7; |
| |
| memset(result, 0, out_length); |
| |
| for (i = 0; i < length; ++i) { |
| u_int8_t first = (data[i] & 0x7f) << b_off; |
| u_int8_t second = (data[i] & 0x7f) >> (8 - b_off); |
| |
| result[d_off] |= first; |
| if (second != 0) |
| result[d_off + 1] = second; |
| |
| b_off += 7; |
| |
| if (b_off >= 8) { |
| d_off += 1; |
| b_off -= 8; |
| } |
| } |
| |
| return out_length; |
| } |
| |
| /* determine power control level for given dBm value, as indicated |
| * by the tables in chapter 4.1.1 of GSM TS 05.05 */ |
| int ms_pwr_ctl_lvl(enum gsm_band band, unsigned int dbm) |
| { |
| switch (band) { |
| case GSM_BAND_400: |
| case GSM_BAND_900: |
| case GSM_BAND_850: |
| if (dbm >= 39) |
| return 0; |
| else if (dbm < 5) |
| return 19; |
| else |
| return 2 + ((39 - dbm) / 2); |
| break; |
| case GSM_BAND_1800: |
| if (dbm >= 36) |
| return 29; |
| else if (dbm >= 34) |
| return 30; |
| else if (dbm >= 32) |
| return 31; |
| else |
| return (30 - dbm) / 2; |
| break; |
| case GSM_BAND_1900: |
| if (dbm >= 33) |
| return 30; |
| else if (dbm >= 32) |
| return 31; |
| else |
| return (30 - dbm) / 2; |
| break; |
| } |
| return -EINVAL; |
| } |
| |
| int ms_pwr_dbm(enum gsm_band band, u_int8_t lvl) |
| { |
| lvl &= 0x1f; |
| |
| switch (band) { |
| case GSM_BAND_400: |
| case GSM_BAND_900: |
| case GSM_BAND_850: |
| if (lvl < 2) |
| return 39; |
| else if (lvl < 20) |
| return 39 - ((lvl - 2) * 2) ; |
| else |
| return 5; |
| break; |
| case GSM_BAND_1800: |
| if (lvl < 16) |
| return 30 - (lvl * 2); |
| else if (lvl < 29) |
| return 0; |
| else |
| return 36 - ((lvl - 29) * 2); |
| break; |
| case GSM_BAND_1900: |
| if (lvl < 16) |
| return 30 - (lvl * 2); |
| else if (lvl < 30) |
| return -EINVAL; |
| else |
| return 33 - (lvl - 30); |
| break; |
| } |
| return -EINVAL; |
| } |
| |
| |