Changes in decoding:
-copied decoding routines from libosmocore to gr-gsm,
-made cmake files entries for new source files and added linking with libosmocodec,
-moved sch.c file to decoding folder.
diff --git a/lib/decoding/osmocom/coding/gsm0503_coding.c b/lib/decoding/osmocom/coding/gsm0503_coding.c
new file mode 100644
index 0000000..afbba88
--- /dev/null
+++ b/lib/decoding/osmocom/coding/gsm0503_coding.c
@@ -0,0 +1,1753 @@
+/*
+ * (C) 2013 by Andreas Eversberg <jolly@eversberg.eu>
+ * (C) 2015 by Alexander Chemeris <Alexander.Chemeris@fairwaves.co>
+ * (C) 2016 by Tom Tsou <tom.tsou@ettus.com>
+ *
+ * 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 <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <osmocom/core/bits.h>
+#include <osmocom/core/conv.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/crcgen.h>
+#include <osmocom/core/endian.h>
+
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+#include "gsm0503.h"
+#include <osmocom/codec/codec.h>
+
+#include "gsm0503_interleaving.h"
+#include "gsm0503_mapping.h"
+#include "gsm0503_tables.h"
+#include "gsm0503_coding.h"
+#include "gsm0503_parity.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+
+/*
+ * EGPRS coding limits
+ */
+
+/* Max header size with parity bits */
+#define EGPRS_HDR_UPP_MAX 54
+
+/* Max encoded header size */
+#define EGPRS_HDR_C_MAX 162
+
+/* Max punctured header size */
+#define EGPRS_HDR_HC_MAX 160
+
+/* Max data block size with parity bits */
+#define EGPRS_DATA_U_MAX 612
+
+/* Max encoded data block size */
+#define EGPRS_DATA_C_MAX 1836
+
+/* Max single block punctured data size */
+#define EGPRS_DATA_DC_MAX 1248
+
+/* Dual block punctured data size */
+#define EGPRS_DATA_C1 612
+#define EGPRS_DATA_C2 EGPRS_DATA_C1
+
+/* TS 101318 Chapter 5.1: 260 bits + 4bit sig */
+#define GSM_FR_BYTES 33
+/* TS 101318 Chapter 5.2: 112 bits, no sig */
+#define GSM_HR_BYTES 14
+/* TS 101318 Chapter 5.3: 244 bits + 4bit sig */
+#define GSM_EFR_BYTES 31
+
+struct gsm0503_mcs_code {
+ uint8_t mcs;
+ uint8_t usf_len;
+
+ /* Header coding */
+ uint8_t hdr_len;
+ uint8_t hdr_code_len;
+ uint8_t hdr_punc_len;
+ const struct osmo_conv_code *hdr_conv;
+ const uint8_t *hdr_punc;
+
+ /* Data coding */
+ uint16_t data_len;
+ uint16_t data_code_len;
+ uint16_t data_punc_len;
+ const struct osmo_conv_code *data_conv;
+ const uint8_t *data_punc[3];
+};
+
+static int osmo_conv_decode_ber(const struct osmo_conv_code *code,
+ const sbit_t *input, ubit_t *output,
+ int *n_errors, int *n_bits_total)
+{
+ int res, i, coded_len;
+ ubit_t recoded[EGPRS_DATA_C_MAX];
+
+ res = osmo_conv_decode(code, input, output);
+
+ if (n_bits_total || n_errors) {
+ coded_len = osmo_conv_encode(code, output, recoded);
+ OSMO_ASSERT(sizeof(recoded) / sizeof(recoded[0]) >= coded_len);
+ }
+
+ /* Count bit errors */
+ if (n_errors) {
+ *n_errors = 0;
+ for (i = 0; i < coded_len; i++) {
+ if (!((recoded[i] && input[i] < 0) ||
+ (!recoded[i] && input[i] > 0)) )
+ *n_errors += 1;
+ }
+ }
+
+ if (n_bits_total)
+ *n_bits_total = coded_len;
+
+ return res;
+}
+
+static int _xcch_decode_cB(uint8_t *l2_data, sbit_t *cB,
+ int *n_errors, int *n_bits_total)
+{
+ ubit_t conv[224];
+ int rv;
+
+ osmo_conv_decode_ber(&gsm0503_xcch, cB,
+ conv, n_errors, n_bits_total);
+
+ rv = osmo_crc64gen_check_bits(&gsm0503_fire_crc40,
+ conv, 184, conv + 184);
+ if (rv)
+ return -1;
+
+ osmo_ubit2pbit_ext(l2_data, 0, conv, 0, 184, 1);
+
+ return 0;
+}
+
+static int _xcch_encode_cB(ubit_t *cB, uint8_t *l2_data)
+{
+ ubit_t conv[224];
+
+ osmo_pbit2ubit_ext(conv, 0, l2_data, 0, 184, 1);
+
+ osmo_crc64gen_set_bits(&gsm0503_fire_crc40, conv, 184, conv + 184);
+
+ osmo_conv_encode(&gsm0503_xcch, conv, cB);
+
+ return 0;
+}
+
+/*
+ * GSM xCCH block transcoding
+ */
+int gsm0503_xcch_decode(uint8_t *l2_data, sbit_t *bursts,
+ int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[456], cB[456];
+ int i;
+
+ for (i = 0; i < 4; i++)
+ gsm0503_xcch_burst_unmap(&iB[i * 114], &bursts[i * 116], NULL, NULL);
+
+ gsm0503_xcch_deinterleave(cB, iB);
+
+ return _xcch_decode_cB(l2_data, cB, n_errors, n_bits_total);
+}
+
+int gsm0503_xcch_encode(ubit_t *bursts, uint8_t *l2_data)
+{
+ ubit_t iB[456], cB[456], hl = 1, hn = 1;
+ int i;
+
+ _xcch_encode_cB(cB, l2_data);
+
+ gsm0503_xcch_interleave(cB, iB);
+
+ for (i = 0; i < 4; i++)
+ gsm0503_xcch_burst_map(&iB[i * 114], &bursts[i * 116], &hl, &hn);
+
+ return 0;
+}
+
+
+
+/*
+ * GSM PDTCH block transcoding
+ */
+
+int gsm0503_pdtch_decode(uint8_t *l2_data, sbit_t *bursts, uint8_t *usf_p,
+ int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[456], cB[676], hl_hn[8];
+ ubit_t conv[456];
+ int i, j, k, rv, best = 0, cs = 0, usf = 0; /* make GCC happy */
+
+ for (i = 0; i < 4; i++)
+ gsm0503_xcch_burst_unmap(&iB[i * 114], &bursts[i * 116],
+ hl_hn + i * 2, hl_hn + i * 2 + 1);
+
+ for (i = 0; i < 4; i++) {
+ for (j = 0, k = 0; j < 8; j++)
+ k += abs(((int)gsm0503_pdtch_hl_hn_sbit[i][j]) - ((int)hl_hn[j]));
+
+ if (i == 0 || k < best) {
+ best = k;
+ cs = i+1;
+ }
+ }
+
+ gsm0503_xcch_deinterleave(cB, iB);
+
+ switch (cs) {
+ case 1:
+ osmo_conv_decode_ber(&gsm0503_xcch, cB,
+ conv, n_errors, n_bits_total);
+
+ rv = osmo_crc64gen_check_bits(&gsm0503_fire_crc40,
+ conv, 184, conv + 184);
+ if (rv)
+ return -1;
+
+ osmo_ubit2pbit_ext(l2_data, 0, conv, 0, 184, 1);
+
+ return 23;
+ case 2:
+ for (i = 587, j = 455; i >= 0; i--) {
+ if (!gsm0503_puncture_cs2[i])
+ cB[i] = cB[j--];
+ else
+ cB[i] = 0;
+ }
+
+ osmo_conv_decode_ber(&gsm0503_cs2, cB,
+ conv, n_errors, n_bits_total);
+
+ for (i = 0; i < 8; i++) {
+ for (j = 0, k = 0; j < 6; j++)
+ k += abs(((int)gsm0503_usf2six[i][j]) - ((int)conv[j]));
+
+ if (i == 0 || k < best) {
+ best = k;
+ usf = i;
+ }
+ }
+
+ conv[3] = usf & 1;
+ conv[4] = (usf >> 1) & 1;
+ conv[5] = (usf >> 2) & 1;
+ if (usf_p)
+ *usf_p = usf;
+
+ rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16,
+ conv + 3, 271, conv + 3 + 271);
+ if (rv)
+ return -1;
+
+ osmo_ubit2pbit_ext(l2_data, 0, conv, 3, 271, 1);
+
+ return 34;
+ case 3:
+ for (i = 675, j = 455; i >= 0; i--) {
+ if (!gsm0503_puncture_cs3[i])
+ cB[i] = cB[j--];
+ else
+ cB[i] = 0;
+ }
+
+ osmo_conv_decode_ber(&gsm0503_cs3, cB,
+ conv, n_errors, n_bits_total);
+
+ for (i = 0; i < 8; i++) {
+ for (j = 0, k = 0; j < 6; j++)
+ k += abs(((int)gsm0503_usf2six[i][j]) - ((int)conv[j]));
+
+ if (i == 0 || k < best) {
+ best = k;
+ usf = i;
+ }
+ }
+
+ conv[3] = usf & 1;
+ conv[4] = (usf >> 1) & 1;
+ conv[5] = (usf >> 2) & 1;
+ if (usf_p)
+ *usf_p = usf;
+
+ rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16,
+ conv + 3, 315, conv + 3 + 315);
+ if (rv)
+ return -1;
+
+ osmo_ubit2pbit_ext(l2_data, 0, conv, 3, 315, 1);
+
+ return 40;
+ case 4:
+ for (i = 12; i < 456; i++)
+ conv[i] = (cB[i] < 0) ? 1 : 0;
+
+ for (i = 0; i < 8; i++) {
+ for (j = 0, k = 0; j < 12; j++)
+ k += abs(((int)gsm0503_usf2twelve_sbit[i][j]) - ((int)cB[j]));
+
+ if (i == 0 || k < best) {
+ best = k;
+ usf = i;
+ }
+ }
+
+ conv[9] = usf & 1;
+ conv[10] = (usf >> 1) & 1;
+ conv[11] = (usf >> 2) & 1;
+ if (usf_p)
+ *usf_p = usf;
+
+ rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16,
+ conv + 9, 431, conv + 9 + 431);
+ if (rv) {
+ *n_bits_total = 456 - 12;
+ *n_errors = *n_bits_total;
+ return -1;
+ }
+
+ *n_bits_total = 456 - 12;
+ *n_errors = 0;
+
+ osmo_ubit2pbit_ext(l2_data, 0, conv, 9, 431, 1);
+
+ return 54;
+ default:
+ *n_bits_total = 0;
+ *n_errors = 0;
+ break;
+ }
+
+ return -1;
+}
+
+int gsm0503_pdtch_encode(ubit_t *bursts, uint8_t *l2_data, uint8_t l2_len)
+{
+ ubit_t iB[456], cB[676];
+ const ubit_t *hl_hn;
+ ubit_t conv[334];
+ int i, j, usf;
+
+ switch (l2_len) {
+ case 23:
+ osmo_pbit2ubit_ext(conv, 0, l2_data, 0, 184, 1);
+
+ osmo_crc64gen_set_bits(&gsm0503_fire_crc40, conv, 184, conv + 184);
+
+ osmo_conv_encode(&gsm0503_xcch, conv, cB);
+
+ hl_hn = gsm0503_pdtch_hl_hn_ubit[0];
+
+ break;
+ case 34:
+ osmo_pbit2ubit_ext(conv, 3, l2_data, 0, 271, 1);
+ usf = l2_data[0] & 0x7;
+
+ osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, conv + 3,
+ 271, conv + 3 + 271);
+
+ memcpy(conv, gsm0503_usf2six[usf], 6);
+
+ osmo_conv_encode(&gsm0503_cs2, conv, cB);
+
+ for (i = 0, j = 0; i < 588; i++)
+ if (!gsm0503_puncture_cs2[i])
+ cB[j++] = cB[i];
+
+ hl_hn = gsm0503_pdtch_hl_hn_ubit[1];
+
+ break;
+ case 40:
+ osmo_pbit2ubit_ext(conv, 3, l2_data, 0, 315, 1);
+ usf = l2_data[0] & 0x7;
+
+ osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, conv + 3,
+ 315, conv + 3 + 315);
+
+ memcpy(conv, gsm0503_usf2six[usf], 6);
+
+ osmo_conv_encode(&gsm0503_cs3, conv, cB);
+
+ for (i = 0, j = 0; i < 676; i++)
+ if (!gsm0503_puncture_cs3[i])
+ cB[j++] = cB[i];
+
+ hl_hn = gsm0503_pdtch_hl_hn_ubit[2];
+
+ break;
+ case 54:
+ osmo_pbit2ubit_ext(cB, 9, l2_data, 0, 431, 1);
+ usf = l2_data[0] & 0x7;
+
+ osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, cB + 9,
+ 431, cB + 9 + 431);
+
+ memcpy(cB, gsm0503_usf2twelve_ubit[usf], 12);
+
+ hl_hn = gsm0503_pdtch_hl_hn_ubit[3];
+
+ break;
+ default:
+ return -1;
+ }
+
+ gsm0503_xcch_interleave(cB, iB);
+
+ for (i = 0; i < 4; i++) {
+ gsm0503_xcch_burst_map(&iB[i * 114], &bursts[i * 116],
+ hl_hn + i * 2, hl_hn + i * 2 + 1);
+ }
+
+ return GSM0503_GPRS_BURSTS_NBITS;
+}
+
+/*
+ * GSM TCH/F FR/EFR transcoding
+ */
+
+static void tch_fr_reassemble(uint8_t *tch_data,
+ ubit_t *b_bits, int net_order)
+{
+ int i, j, k, l, o;
+
+ tch_data[0] = 0xd << 4;
+ memset(tch_data + 1, 0, 32);
+
+ if (net_order) {
+ for (i = 0, j = 4; i < 260; i++, j++)
+ tch_data[j >> 3] |= (b_bits[i] << (7 - (j & 7)));
+
+ return;
+ }
+
+ /* reassemble d-bits */
+ i = 0; /* counts bits */
+ j = 4; /* counts output bits */
+ k = gsm0503_gsm_fr_map[0]-1; /* current number bit in element */
+ l = 0; /* counts element bits */
+ o = 0; /* offset input bits */
+ while (i < 260) {
+ tch_data[j >> 3] |= (b_bits[k + o] << (7 - (j & 7)));
+ if (--k < 0) {
+ o += gsm0503_gsm_fr_map[l];
+ k = gsm0503_gsm_fr_map[++l]-1;
+ }
+ i++;
+ j++;
+ }
+}
+
+static void tch_fr_disassemble(ubit_t *b_bits,
+ uint8_t *tch_data, int net_order)
+{
+ int i, j, k, l, o;
+
+ if (net_order) {
+ for (i = 0, j = 4; i < 260; i++, j++)
+ b_bits[i] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1;
+
+ return;
+ }
+
+ i = 0; /* counts bits */
+ j = 4; /* counts input bits */
+ k = gsm0503_gsm_fr_map[0] - 1; /* current number bit in element */
+ l = 0; /* counts element bits */
+ o = 0; /* offset output bits */
+ while (i < 260) {
+ b_bits[k + o] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1;
+ if (--k < 0) {
+ o += gsm0503_gsm_fr_map[l];
+ k = gsm0503_gsm_fr_map[++l] - 1;
+ }
+ i++;
+ j++;
+ }
+}
+
+static void tch_hr_reassemble(uint8_t *tch_data, ubit_t *b_bits)
+{
+ int i, j;
+
+ tch_data[0] = 0x00; /* F = 0, FT = 000 */
+ memset(tch_data + 1, 0, 14);
+
+ for (i = 0, j = 8; i < 112; i++, j++)
+ tch_data[j >> 3] |= (b_bits[i] << (7 - (j & 7)));
+}
+
+static void tch_hr_disassemble(ubit_t *b_bits, uint8_t *tch_data)
+{
+ int i, j;
+
+ for (i = 0, j = 8; i < 112; i++, j++)
+ b_bits[i] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1;
+}
+
+static void tch_efr_reassemble(uint8_t *tch_data, ubit_t *b_bits)
+{
+ int i, j;
+
+ tch_data[0] = 0xc << 4;
+ memset(tch_data + 1, 0, 30);
+
+ for (i = 0, j = 4; i < 244; i++, j++)
+ tch_data[j >> 3] |= (b_bits[i] << (7 - (j & 7)));
+}
+
+static void tch_efr_disassemble(ubit_t *b_bits, uint8_t *tch_data)
+{
+ int i, j;
+
+ for (i = 0, j = 4; i < 244; i++, j++)
+ b_bits[i] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1;
+}
+
+static void tch_amr_reassemble(uint8_t *tch_data, ubit_t *d_bits, int len)
+{
+ int i, j;
+
+ memset(tch_data, 0, (len + 7) >> 3);
+
+ for (i = 0, j = 0; i < len; i++, j++)
+ tch_data[j >> 3] |= (d_bits[i] << (7 - (j & 7)));
+}
+
+static void tch_amr_disassemble(ubit_t *d_bits, uint8_t *tch_data, int len)
+{
+ int i, j;
+
+ for (i = 0, j = 0; i < len; i++, j++)
+ d_bits[i] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1;
+}
+
+static void tch_fr_d_to_b(ubit_t *b_bits, ubit_t *d_bits)
+{
+ int i;
+
+ for (i = 0; i < 260; i++)
+ b_bits[gsm610_bitorder[i]] = d_bits[i];
+}
+
+static void tch_fr_b_to_d(ubit_t *d_bits, ubit_t *b_bits)
+{
+ int i;
+
+ for (i = 0; i < 260; i++)
+ d_bits[i] = b_bits[gsm610_bitorder[i]];
+}
+
+static void tch_hr_d_to_b(ubit_t *b_bits, ubit_t *d_bits)
+{
+ int i;
+
+ const uint16_t *map;
+
+ if (!d_bits[93] && !d_bits[94])
+ map = gsm620_unvoiced_bitorder;
+ else
+ map = gsm620_voiced_bitorder;
+
+ for (i = 0; i < 112; i++)
+ b_bits[map[i]] = d_bits[i];
+}
+
+static void tch_hr_b_to_d(ubit_t *d_bits, ubit_t *b_bits)
+{
+ int i;
+ const uint16_t *map;
+
+ if (!b_bits[34] && !b_bits[35])
+ map = gsm620_unvoiced_bitorder;
+ else
+ map = gsm620_voiced_bitorder;
+
+ for (i = 0; i < 112; i++)
+ d_bits[i] = b_bits[map[i]];
+}
+
+static void tch_efr_d_to_w(ubit_t *b_bits, ubit_t *d_bits)
+{
+ int i;
+
+ for (i = 0; i < 260; i++)
+ b_bits[gsm660_bitorder[i]] = d_bits[i];
+}
+
+static void tch_efr_w_to_d(ubit_t *d_bits, ubit_t *b_bits)
+{
+ int i;
+
+ for (i = 0; i < 260; i++)
+ d_bits[i] = b_bits[gsm660_bitorder[i]];
+}
+
+static void tch_efr_protected(ubit_t *s_bits, ubit_t *b_bits)
+{
+ int i;
+
+ for (i = 0; i < 65; i++)
+ b_bits[i] = s_bits[gsm0503_gsm_efr_protected_bits[i] - 1];
+}
+
+static void tch_fr_unreorder(ubit_t *d, ubit_t *p, ubit_t *u)
+{
+ int i;
+
+ for (i = 0; i < 91; i++) {
+ d[i << 1] = u[i];
+ d[(i << 1) + 1] = u[184 - i];
+ }
+
+ for (i = 0; i < 3; i++)
+ p[i] = u[91 + i];
+}
+
+static void tch_fr_reorder(ubit_t *u, ubit_t *d, ubit_t *p)
+{
+ int i;
+
+ for (i = 0; i < 91; i++) {
+ u[i] = d[i << 1];
+ u[184 - i] = d[(i << 1) + 1];
+ }
+
+ for (i = 0; i < 3; i++)
+ u[91 + i] = p[i];
+}
+
+static void tch_hr_unreorder(ubit_t *d, ubit_t *p, ubit_t *u)
+{
+ memcpy(d, u, 95);
+ memcpy(p, u + 95, 3);
+}
+
+static void tch_hr_reorder(ubit_t *u, ubit_t *d, ubit_t *p)
+{
+ memcpy(u, d, 95);
+ memcpy(u + 95, p, 3);
+}
+
+static void tch_efr_reorder(ubit_t *w, ubit_t *s, ubit_t *p)
+{
+ memcpy(w, s, 71);
+ w[71] = w[72] = s[69];
+ memcpy(w + 73, s + 71, 50);
+ w[123] = w[124] = s[119];
+ memcpy(w + 125, s + 121, 53);
+ w[178] = w[179] = s[172];
+ memcpy(w + 180, s + 174, 50);
+ w[230] = w[231] = s[222];
+ memcpy(w + 232, s + 224, 20);
+ memcpy(w + 252, p, 8);
+}
+
+static void tch_efr_unreorder(ubit_t *s, ubit_t *p, ubit_t *w)
+{
+ int sum;
+
+ memcpy(s, w, 71);
+ sum = s[69] + w[71] + w[72];
+ s[69] = (sum > 2);
+ memcpy(s + 71, w + 73, 50);
+ sum = s[119] + w[123] + w[124];
+ s[119] = (sum > 2);
+ memcpy(s + 121, w + 125, 53);
+ sum = s[172] + w[178] + w[179];
+ s[172] = (sum > 2);
+ memcpy(s + 174, w + 180, 50);
+ sum = s[220] + w[230] + w[231];
+ s[222] = (sum > 2);
+ memcpy(s + 224, w + 232, 20);
+ memcpy(p, w + 252, 8);
+}
+
+static void tch_amr_merge(ubit_t *u, ubit_t *d, ubit_t *p, int len, int prot)
+{
+ memcpy(u, d, prot);
+ memcpy(u + prot, p, 6);
+ memcpy(u + prot + 6, d + prot, len - prot);
+}
+
+static void tch_amr_unmerge(ubit_t *d, ubit_t *p,
+ ubit_t *u, int len, int prot)
+{
+ memcpy(d, u, prot);
+ memcpy(p, u+prot, 6);
+ memcpy(d + prot, u + prot + 6, len - prot);
+}
+
+int gsm0503_tch_fr_decode(uint8_t *tch_data, sbit_t *bursts,
+ int net_order, int efr, int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[912], cB[456], h;
+ ubit_t conv[185], s[244], w[260], b[65], d[260], p[8];
+ int i, rv, len, steal = 0;
+
+ for (i=0; i<8; i++) {
+ gsm0503_tch_burst_unmap(&iB[i * 114],
+ &bursts[i * 116], &h, i >> 2);
+ steal -= h;
+ }
+
+ gsm0503_tch_fr_deinterleave(cB, iB);
+
+ if (steal > 0) {
+ rv = _xcch_decode_cB(tch_data, cB, n_errors, n_bits_total);
+ if (rv) {
+ /* Error decoding FACCH frame */
+ return -1;
+ }
+
+ return 23;
+ }
+
+ osmo_conv_decode_ber(&gsm0503_tch_fr, cB, conv, n_errors, n_bits_total);
+
+ tch_fr_unreorder(d, p, conv);
+
+ for (i = 0; i < 78; i++)
+ d[i + 182] = (cB[i + 378] < 0) ? 1 : 0;
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_tch_fr_crc3, d, 50, p);
+ if (rv) {
+ /* Error checking CRC8 for the FR part of an EFR/FR frame */
+ return -1;
+ }
+
+ if (efr) {
+ tch_efr_d_to_w(w, d);
+
+ tch_efr_unreorder(s, p, w);
+
+ tch_efr_protected(s, b);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_tch_efr_crc8, b, 65, p);
+ if (rv) {
+ /* Error checking CRC8 for the EFR part of an EFR frame */
+ return -1;
+ }
+
+ tch_efr_reassemble(tch_data, s);
+
+ len = GSM_EFR_BYTES;
+ } else {
+ tch_fr_d_to_b(w, d);
+
+ tch_fr_reassemble(tch_data, w, net_order);
+
+ len = GSM_FR_BYTES;
+ }
+
+ return len;
+}
+
+int gsm0503_tch_fr_encode(ubit_t *bursts, uint8_t *tch_data,
+ int len, int net_order)
+{
+ ubit_t iB[912], cB[456], h;
+ ubit_t conv[185], w[260], b[65], s[244], d[260], p[8];
+ int i;
+
+ switch (len) {
+ case GSM_EFR_BYTES: /* TCH EFR */
+
+ tch_efr_disassemble(s, tch_data);
+
+ tch_efr_protected(s, b);
+
+ osmo_crc8gen_set_bits(&gsm0503_tch_efr_crc8, b, 65, p);
+
+ tch_efr_reorder(w, s, p);
+
+ tch_efr_w_to_d(d, w);
+
+ goto coding_efr_fr;
+ case GSM_FR_BYTES: /* TCH FR */
+ tch_fr_disassemble(w, tch_data, net_order);
+
+ tch_fr_b_to_d(d, w);
+
+coding_efr_fr:
+ osmo_crc8gen_set_bits(&gsm0503_tch_fr_crc3, d, 50, p);
+
+ tch_fr_reorder(conv, d, p);
+
+ memcpy(cB + 378, d + 182, 78);
+
+ osmo_conv_encode(&gsm0503_tch_fr, conv, cB);
+
+ h = 0;
+
+ break;
+ case GSM_MACBLOCK_LEN: /* FACCH */
+ _xcch_encode_cB(cB, tch_data);
+
+ h = 1;
+
+ break;
+ default:
+ return -1;
+ }
+
+ gsm0503_tch_fr_interleave(cB, iB);
+
+ for (i = 0; i < 8; i++) {
+ gsm0503_tch_burst_map(&iB[i * 114],
+ &bursts[i * 116], &h, i >> 2);
+ }
+
+ return 0;
+}
+
+int gsm0503_tch_hr_decode(uint8_t *tch_data, sbit_t *bursts, int odd,
+ int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[912], cB[456], h;
+ ubit_t conv[98], b[112], d[112], p[3];
+ int i, rv, steal = 0;
+
+ /* Only unmap the stealing bits */
+ if (!odd) {
+ for (i = 0; i < 4; i++) {
+ gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 0);
+ steal -= h;
+ }
+
+ for (i = 2; i < 5; i++) {
+ gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 1);
+ steal -= h;
+ }
+ }
+
+ /* If we found a stole FACCH, but only at correct alignment */
+ if (steal > 0) {
+ for (i = 0; i < 6; i++) {
+ gsm0503_tch_burst_unmap(&iB[i * 114],
+ &bursts[i * 116], NULL, i >> 2);
+ }
+
+ for (i = 2; i < 4; i++) {
+ gsm0503_tch_burst_unmap(&iB[i * 114 + 456],
+ &bursts[i * 116], NULL, 1);
+ }
+
+ gsm0503_tch_fr_deinterleave(cB, iB);
+
+ rv = _xcch_decode_cB(tch_data, cB, n_errors, n_bits_total);
+ if (rv) {
+ /* Error decoding FACCH frame */
+ return -1;
+ }
+
+ return GSM_MACBLOCK_LEN;
+ }
+
+ for (i = 0; i < 4; i++) {
+ gsm0503_tch_burst_unmap(&iB[i * 114],
+ &bursts[i * 116], NULL, i >> 1);
+ }
+
+ gsm0503_tch_hr_deinterleave(cB, iB);
+
+ osmo_conv_decode_ber(&gsm0503_tch_hr, cB, conv, n_errors, n_bits_total);
+
+ tch_hr_unreorder(d, p, conv);
+
+ for (i = 0; i < 17; i++)
+ d[i + 95] = (cB[i + 211] < 0) ? 1 : 0;
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_tch_fr_crc3, d + 73, 22, p);
+ if (rv) {
+ /* Error checking CRC8 for an HR frame */
+ return -1;
+ }
+
+ tch_hr_d_to_b(b, d);
+
+ tch_hr_reassemble(tch_data, b);
+
+ return 15;
+}
+
+int gsm0503_tch_hr_encode(ubit_t *bursts, uint8_t *tch_data, int len)
+{
+ ubit_t iB[912], cB[456], h;
+ ubit_t conv[98], b[112], d[112], p[3];
+ int i;
+
+ switch (len) {
+ case 15: /* TCH HR */
+ tch_hr_disassemble(b, tch_data);
+
+ tch_hr_b_to_d(d, b);
+
+ osmo_crc8gen_set_bits(&gsm0503_tch_fr_crc3, d + 73, 22, p);
+
+ tch_hr_reorder(conv, d, p);
+
+ osmo_conv_encode(&gsm0503_tch_hr, conv, cB);
+
+ memcpy(cB + 211, d + 95, 17);
+
+ h = 0;
+
+ gsm0503_tch_hr_interleave(cB, iB);
+
+ for (i = 0; i < 4; i++) {
+ gsm0503_tch_burst_map(&iB[i * 114],
+ &bursts[i * 116], &h, i >> 1);
+ }
+
+ break;
+ case GSM_MACBLOCK_LEN: /* FACCH */
+ _xcch_encode_cB(cB, tch_data);
+
+ h = 1;
+
+ gsm0503_tch_fr_interleave(cB, iB);
+
+ for (i=0; i<6; i++) {
+ gsm0503_tch_burst_map(&iB[i * 114],
+ &bursts[i * 116], &h, i >> 2);
+ }
+
+ for (i=2; i<4; i++) {
+ gsm0503_tch_burst_map(&iB[i * 114 + 456],
+ &bursts[i * 116], &h, 1);
+ }
+
+ break;
+ default:
+ return -1;
+ }
+
+ return 0;
+}
+
+int gsm0503_tch_afs_decode(uint8_t *tch_data, sbit_t *bursts,
+ int codec_mode_req, uint8_t *codec, int codecs, uint8_t *ft,
+ uint8_t *cmr, int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[912], cB[456], h;
+ ubit_t d[244], p[6], conv[250];
+ int i, j, k, best = 0, rv, len, steal = 0, id = 0;
+ *n_errors = 0; *n_bits_total = 0;
+
+ for (i=0; i<8; i++) {
+ gsm0503_tch_burst_unmap(&iB[i * 114], &bursts[i * 116], &h, i >> 2);
+ steal -= h;
+ }
+
+ gsm0503_tch_fr_deinterleave(cB, iB);
+
+ if (steal > 0) {
+ rv = _xcch_decode_cB(tch_data, cB, n_errors, n_bits_total);
+ if (rv) {
+ /* Error decoding FACCH frame */
+ return -1;
+ }
+
+ return GSM_MACBLOCK_LEN;
+ }
+
+ for (i = 0; i < 4; i++) {
+ for (j = 0, k = 0; j < 8; j++)
+ k += abs(((int)gsm0503_afs_ic_sbit[i][j]) - ((int)cB[j]));
+
+ if (i == 0 || k < best) {
+ best = k;
+ id = i;
+ }
+ }
+
+ /* Check if indicated codec fits into range of codecs */
+ if (id >= codecs) {
+ /* Codec mode out of range, return id */
+ return id;
+ }
+
+ switch ((codec_mode_req) ? codec[*ft] : codec[id]) {
+ case 7: /* TCH/AFS12.2 */
+ osmo_conv_decode_ber(&gsm0503_tch_afs_12_2, cB + 8,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 244, 81);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 81, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 12.2 frame */
+ return -1;
+ }
+
+ tch_amr_reassemble(tch_data, d, 244);
+
+ len = 31;
+
+ break;
+ case 6: /* TCH/AFS10.2 */
+ osmo_conv_decode_ber(&gsm0503_tch_afs_10_2, cB + 8,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 204, 65);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 65, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 10.2 frame */
+ return -1;
+ }
+
+ tch_amr_reassemble(tch_data, d, 204);
+
+ len = 26;
+
+ break;
+ case 5: /* TCH/AFS7.95 */
+ osmo_conv_decode_ber(&gsm0503_tch_afs_7_95, cB + 8,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 159, 75);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 75, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 7.95 frame */
+ return -1;
+ }
+
+ tch_amr_reassemble(tch_data, d, 159);
+
+ len = 20;
+
+ break;
+ case 4: /* TCH/AFS7.4 */
+ osmo_conv_decode_ber(&gsm0503_tch_afs_7_4, cB + 8,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 148, 61);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 61, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 7.4 frame */
+ return -1;
+ }
+
+ tch_amr_reassemble(tch_data, d, 148);
+
+ len = 19;
+
+ break;
+ case 3: /* TCH/AFS6.7 */
+ osmo_conv_decode_ber(&gsm0503_tch_afs_6_7, cB + 8,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 134, 55);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 6.7 frame */
+ return -1;
+ }
+
+ tch_amr_reassemble(tch_data, d, 134);
+
+ len = 17;
+
+ break;
+ case 2: /* TCH/AFS5.9 */
+ osmo_conv_decode_ber(&gsm0503_tch_afs_5_9, cB + 8,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 118, 55);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 5.9 frame */
+ return -1;
+ }
+
+ tch_amr_reassemble(tch_data, d, 118);
+
+ len = 15;
+
+ break;
+ case 1: /* TCH/AFS5.15 */
+ osmo_conv_decode_ber(&gsm0503_tch_afs_5_15, cB + 8,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 103, 49);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 49, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 5.15 frame */
+ return -1;
+ }
+
+ tch_amr_reassemble(tch_data, d, 103);
+
+ len = 13;
+
+ break;
+ case 0: /* TCH/AFS4.75 */
+ osmo_conv_decode_ber(&gsm0503_tch_afs_4_75, cB + 8,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 95, 39);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 39, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 4.75 frame */
+ return -1;
+ }
+
+ tch_amr_reassemble(tch_data, d, 95);
+
+ len = 12;
+
+ break;
+ default:
+ /* Unknown frame type */
+ *n_bits_total = 448;
+ *n_errors = *n_bits_total;
+ return -1;
+ }
+
+ /* Change codec request / indication, if frame is valid */
+ if (codec_mode_req)
+ *cmr = id;
+ else
+ *ft = id;
+
+ return len;
+}
+
+int gsm0503_tch_afs_encode(ubit_t *bursts, uint8_t *tch_data, int len,
+ int codec_mode_req, uint8_t *codec, int codecs, uint8_t ft,
+ uint8_t cmr)
+{
+ ubit_t iB[912], cB[456], h;
+ ubit_t d[244], p[6], conv[250];
+ int i;
+ uint8_t id;
+
+ if (len == GSM_MACBLOCK_LEN) { /* FACCH */
+ _xcch_encode_cB(cB, tch_data);
+
+ h = 1;
+
+ goto facch;
+ }
+
+ h = 0;
+
+ if (codec_mode_req) {
+ if (cmr >= codecs) {
+ /* FIXME: CMR ID is not in codec list! */
+ return -1;
+ }
+ id = cmr;
+ } else {
+ if (ft >= codecs) {
+ /* FIXME: FT ID is not in codec list! */
+ return -1;
+ }
+ id = ft;
+ }
+
+ switch (codec[ft]) {
+ case 7: /* TCH/AFS12.2 */
+ if (len != 31)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 244);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 81, p);
+
+ tch_amr_merge(conv, d, p, 244, 81);
+
+ osmo_conv_encode(&gsm0503_tch_afs_12_2, conv, cB + 8);
+
+ break;
+ case 6: /* TCH/AFS10.2 */
+ if (len != 26)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 204);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 65, p);
+
+ tch_amr_merge(conv, d, p, 204, 65);
+
+ osmo_conv_encode(&gsm0503_tch_afs_10_2, conv, cB + 8);
+
+ break;
+ case 5: /* TCH/AFS7.95 */
+ if (len != 20)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 159);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 75, p);
+
+ tch_amr_merge(conv, d, p, 159, 75);
+
+ osmo_conv_encode(&gsm0503_tch_afs_7_95, conv, cB + 8);
+
+ break;
+ case 4: /* TCH/AFS7.4 */
+ if (len != 19)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 148);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 61, p);
+
+ tch_amr_merge(conv, d, p, 148, 61);
+
+ osmo_conv_encode(&gsm0503_tch_afs_7_4, conv, cB + 8);
+
+ break;
+ case 3: /* TCH/AFS6.7 */
+ if (len != 17)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 134);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p);
+
+ tch_amr_merge(conv, d, p, 134, 55);
+
+ osmo_conv_encode(&gsm0503_tch_afs_6_7, conv, cB + 8);
+
+ break;
+ case 2: /* TCH/AFS5.9 */
+ if (len != 15)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 118);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p);
+
+ tch_amr_merge(conv, d, p, 118, 55);
+
+ osmo_conv_encode(&gsm0503_tch_afs_5_9, conv, cB + 8);
+
+ break;
+ case 1: /* TCH/AFS5.15 */
+ if (len != 13)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 103);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 49, p);
+
+ tch_amr_merge(conv, d, p, 103, 49);
+
+ osmo_conv_encode(&gsm0503_tch_afs_5_15, conv, cB + 8);
+
+ break;
+ case 0: /* TCH/AFS4.75 */
+ if (len != 12)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 95);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 39, p);
+
+ tch_amr_merge(conv, d, p, 95, 39);
+
+ osmo_conv_encode(&gsm0503_tch_afs_4_75, conv, cB + 8);
+
+ break;
+ default:
+ /* FIXME: FT %ft is not supported */
+ return -1;
+ }
+
+ memcpy(cB, gsm0503_afs_ic_ubit[id], 8);
+
+facch:
+ gsm0503_tch_fr_interleave(cB, iB);
+
+ for (i = 0; i < 8; i++) {
+ gsm0503_tch_burst_map(&iB[i * 114],
+ &bursts[i * 116], &h, i >> 2);
+ }
+
+ return 0;
+
+invalid_length:
+ /* FIXME: payload length %len does not comply with codec type %ft */
+ return -1;
+}
+
+int gsm0503_tch_ahs_decode(uint8_t *tch_data, sbit_t *bursts, int odd,
+ int codec_mode_req, uint8_t *codec, int codecs, uint8_t *ft,
+ uint8_t *cmr, int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[912], cB[456], h;
+ ubit_t d[244], p[6], conv[135];
+ int i, j, k, best = 0, rv, len, steal = 0, id = 0;
+
+ /* only unmap the stealing bits */
+ if (!odd) {
+ for (i = 0; i < 4; i++) {
+ gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 0);
+ steal -= h;
+ }
+ for (i = 2; i < 5; i++) {
+ gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 1);
+ steal -= h;
+ }
+ }
+
+ /* if we found a stole FACCH, but only at correct alignment */
+ if (steal > 0) {
+ for (i = 0; i < 6; i++) {
+ gsm0503_tch_burst_unmap(&iB[i * 114],
+ &bursts[i * 116], NULL, i >> 2);
+ }
+
+ for (i = 2; i < 4; i++) {
+ gsm0503_tch_burst_unmap(&iB[i * 114 + 456],
+ &bursts[i * 116], NULL, 1);
+ }
+
+ gsm0503_tch_fr_deinterleave(cB, iB);
+
+ rv = _xcch_decode_cB(tch_data, cB, n_errors, n_bits_total);
+ if (rv) {
+ /* Error decoding FACCH frame */
+ return -1;
+ }
+
+ return GSM_MACBLOCK_LEN;
+ }
+
+ for (i = 0; i < 4; i++) {
+ gsm0503_tch_burst_unmap(&iB[i * 114],
+ &bursts[i * 116], NULL, i >> 1);
+ }
+
+ gsm0503_tch_hr_deinterleave(cB, iB);
+
+ for (i = 0; i < 4; i++) {
+ for (j = 0, k = 0; j < 4; j++)
+ k += abs(((int)gsm0503_ahs_ic_sbit[i][j]) - ((int)cB[j]));
+
+ if (i == 0 || k < best) {
+ best = k;
+ id = i;
+ }
+ }
+
+ /* Check if indicated codec fits into range of codecs */
+ if (id >= codecs) {
+ /* Codec mode out of range, return id */
+ return id;
+ }
+
+ switch ((codec_mode_req) ? codec[*ft] : codec[id]) {
+ case 5: /* TCH/AHS7.95 */
+ osmo_conv_decode_ber(&gsm0503_tch_ahs_7_95, cB + 4,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 123, 67);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 67, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 7.95 frame */
+ return -1;
+ }
+
+ for (i = 0; i < 36; i++)
+ d[i + 123] = (cB[i + 192] < 0) ? 1 : 0;
+
+ tch_amr_reassemble(tch_data, d, 159);
+
+ len = 20;
+
+ break;
+ case 4: /* TCH/AHS7.4 */
+ osmo_conv_decode_ber(&gsm0503_tch_ahs_7_4, cB + 4,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 120, 61);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 61, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 7.4 frame */
+ return -1;
+ }
+
+ for (i = 0; i < 28; i++)
+ d[i + 120] = (cB[i + 200] < 0) ? 1 : 0;
+
+ tch_amr_reassemble(tch_data, d, 148);
+
+ len = 19;
+
+ break;
+ case 3: /* TCH/AHS6.7 */
+ osmo_conv_decode_ber(&gsm0503_tch_ahs_6_7, cB + 4,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 110, 55);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 6.7 frame */
+ return -1;
+ }
+
+ for (i = 0; i < 24; i++)
+ d[i + 110] = (cB[i + 204] < 0) ? 1 : 0;
+
+ tch_amr_reassemble(tch_data, d, 134);
+
+ len = 17;
+
+ break;
+ case 2: /* TCH/AHS5.9 */
+ osmo_conv_decode_ber(&gsm0503_tch_ahs_5_9, cB + 4,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 102, 55);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 5.9 frame */
+ return -1;
+ }
+
+ for (i = 0; i < 16; i++)
+ d[i + 102] = (cB[i + 212] < 0) ? 1 : 0;
+
+ tch_amr_reassemble(tch_data, d, 118);
+
+ len = 15;
+
+ break;
+ case 1: /* TCH/AHS5.15 */
+ osmo_conv_decode_ber(&gsm0503_tch_ahs_5_15, cB + 4,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 91, 49);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 49, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 5.15 frame */
+ return -1;
+ }
+
+ for (i = 0; i < 12; i++)
+ d[i + 91] = (cB[i + 216] < 0) ? 1 : 0;
+
+ tch_amr_reassemble(tch_data, d, 103);
+
+ len = 13;
+
+ break;
+ case 0: /* TCH/AHS4.75 */
+ osmo_conv_decode_ber(&gsm0503_tch_ahs_4_75, cB + 4,
+ conv, n_errors, n_bits_total);
+
+ tch_amr_unmerge(d, p, conv, 83, 39);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 39, p);
+ if (rv) {
+ /* Error checking CRC8 for an AMR 4.75 frame */
+ return -1;
+ }
+
+ for (i = 0; i < 12; i++)
+ d[i + 83] = (cB[i + 216] < 0) ? 1 : 0;
+
+ tch_amr_reassemble(tch_data, d, 95);
+
+ len = 12;
+
+ break;
+ default:
+ /* Unknown frame type */
+ *n_bits_total = 159;
+ *n_errors = *n_bits_total;
+ return -1;
+ }
+
+ /* Change codec request / indication, if frame is valid */
+ if (codec_mode_req)
+ *cmr = id;
+ else
+ *ft = id;
+
+ return len;
+}
+
+int gsm0503_tch_ahs_encode(ubit_t *bursts, uint8_t *tch_data, int len,
+ int codec_mode_req, uint8_t *codec, int codecs, uint8_t ft,
+ uint8_t cmr)
+{
+ ubit_t iB[912], cB[456], h;
+ ubit_t d[244], p[6], conv[135];
+ int i;
+ uint8_t id;
+
+ if (len == GSM_MACBLOCK_LEN) { /* FACCH */
+ _xcch_encode_cB(cB, tch_data);
+
+ h = 1;
+
+ gsm0503_tch_fr_interleave(cB, iB);
+
+ for (i = 0; i < 6; i++)
+ gsm0503_tch_burst_map(&iB[i * 114], &bursts[i * 116],
+ &h, i >> 2);
+ for (i = 2; i < 4; i++)
+ gsm0503_tch_burst_map(&iB[i * 114 + 456],
+ &bursts[i * 116], &h, 1);
+
+ return 0;
+ }
+
+ h = 0;
+
+ if (codec_mode_req) {
+ if (cmr >= codecs) {
+ /* FIXME: CMR ID %d not in codec list */
+ return -1;
+ }
+ id = cmr;
+ } else {
+ if (ft >= codecs) {
+ /* FIXME: FT ID %d not in codec list */
+ return -1;
+ }
+ id = ft;
+ }
+
+ switch (codec[ft]) {
+ case 5: /* TCH/AHS7.95 */
+ if (len != 20)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 159);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 67, p);
+
+ tch_amr_merge(conv, d, p, 123, 67);
+
+ osmo_conv_encode(&gsm0503_tch_ahs_7_95, conv, cB + 4);
+
+ memcpy(cB + 192, d + 123, 36);
+
+ break;
+ case 4: /* TCH/AHS7.4 */
+ if (len != 19)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 148);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 61, p);
+
+ tch_amr_merge(conv, d, p, 120, 61);
+
+ osmo_conv_encode(&gsm0503_tch_ahs_7_4, conv, cB + 4);
+
+ memcpy(cB + 200, d + 120, 28);
+
+ break;
+ case 3: /* TCH/AHS6.7 */
+ if (len != 17)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 134);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p);
+
+ tch_amr_merge(conv, d, p, 110, 55);
+
+ osmo_conv_encode(&gsm0503_tch_ahs_6_7, conv, cB + 4);
+
+ memcpy(cB + 204, d + 110, 24);
+
+ break;
+ case 2: /* TCH/AHS5.9 */
+ if (len != 15)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 118);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p);
+
+ tch_amr_merge(conv, d, p, 102, 55);
+
+ osmo_conv_encode(&gsm0503_tch_ahs_5_9, conv, cB + 4);
+
+ memcpy(cB + 212, d + 102, 16);
+
+ break;
+ case 1: /* TCH/AHS5.15 */
+ if (len != 13)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 103);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 49, p);
+
+ tch_amr_merge(conv, d, p, 91, 49);
+
+ osmo_conv_encode(&gsm0503_tch_ahs_5_15, conv, cB + 4);
+
+ memcpy(cB + 216, d + 91, 12);
+
+ break;
+ case 0: /* TCH/AHS4.75 */
+ if (len != 12)
+ goto invalid_length;
+
+ tch_amr_disassemble(d, tch_data, 95);
+
+ osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 39, p);
+
+ tch_amr_merge(conv, d, p, 83, 39);
+
+ osmo_conv_encode(&gsm0503_tch_ahs_4_75, conv, cB + 4);
+
+ memcpy(cB + 216, d + 83, 12);
+
+ break;
+ default:
+ /* FIXME: FT %ft is not supported */
+ return -1;
+ }
+
+ memcpy(cB, gsm0503_afs_ic_ubit[id], 4);
+
+ gsm0503_tch_hr_interleave(cB, iB);
+
+ for (i = 0; i < 4; i++)
+ gsm0503_tch_burst_map(&iB[i * 114], &bursts[i * 116], &h, i >> 1);
+
+ return 0;
+
+invalid_length:
+ /* FIXME: payload length %len does not comply with codec type %ft */
+ return -1;
+}
+
+/*
+ * GSM RACH transcoding
+ */
+
+/*
+ * GSM RACH apply BSIC to parity
+ *
+ * p(j) = p(j) xor b(j) j = 0, ..., 5
+ * b(0) = MSB of PLMN colour code
+ * b(5) = LSB of BS colour code
+ */
+static int rach_apply_bsic(ubit_t *d, uint8_t bsic)
+{
+ int i;
+
+ /* Apply it */
+ for (i = 0; i < 6; i++)
+ d[8 + i] ^= ((bsic >> (5 - i)) & 1);
+
+ return 0;
+}
+
+int gsm0503_rach_decode(uint8_t *ra, sbit_t *burst, uint8_t bsic)
+{
+ ubit_t conv[14];
+ int rv;
+
+ osmo_conv_decode(&gsm0503_rach, burst, conv);
+
+ rach_apply_bsic(conv, bsic);
+
+ rv = osmo_crc8gen_check_bits(&gsm0503_rach_crc6, conv, 8, conv + 8);
+ if (rv)
+ return -1;
+
+ osmo_ubit2pbit_ext(ra, 0, conv, 0, 8, 1);
+
+ return 0;
+}
+
+int gsm0503_rach_encode(ubit_t *burst, uint8_t *ra, uint8_t bsic)
+{
+ ubit_t conv[14];
+
+ osmo_pbit2ubit_ext(conv, 0, ra, 0, 8, 1);
+
+ osmo_crc8gen_set_bits(&gsm0503_rach_crc6, conv, 8, conv + 8);
+
+ rach_apply_bsic(conv, bsic);
+
+ osmo_conv_encode(&gsm0503_rach, conv, burst);
+
+ return 0;
+}
+
+/*
+ * GSM SCH transcoding
+ */
+int gsm0503_sch_decode(uint8_t *sb_info, sbit_t *burst)
+{
+ ubit_t conv[35];
+ int rv;
+
+ osmo_conv_decode(&gsm0503_sch, burst, conv);
+
+ rv = osmo_crc16gen_check_bits(&gsm0503_sch_crc10, conv, 25, conv + 25);
+ if (rv)
+ return -1;
+
+ osmo_ubit2pbit_ext(sb_info, 0, conv, 0, 25, 1);
+
+ return 0;
+}
+
+int gsm0503_sch_encode(ubit_t *burst, uint8_t *sb_info)
+{
+ ubit_t conv[35];
+
+ osmo_pbit2ubit_ext(conv, 0, sb_info, 0, 25, 1);
+
+ osmo_crc16gen_set_bits(&gsm0503_sch_crc10, conv, 25, conv + 25);
+
+ osmo_conv_encode(&gsm0503_sch, conv, burst);
+
+ return 0;
+}