1 files changed, 78 insertions, 0 deletions
diff --git a/src/ecu_fr.c b/src/ecu_fr.c
new file mode 100644
index 0000000..db55fec
--- /dev/null
+++ b/src/ecu_fr.c
@@ -0,0 +1,78 @@
+/* ECU (Error Concealment Unit) for FR */
+
+/*
+ * This file is part of GAPK (GSM Audio Pocket Knife).
+ *
+ * (C) 2018 by Vadim Yanitskiy <axilirator@gmail.com>
+ *
+ * All Rights Reserved
+ *
+ * GAPK 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GAPK 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 GAPK.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <assert.h>
+#include <stdbool.h>
+
+#include <osmocom/gapk/codecs.h>
+#include <osmocom/codec/ecu.h>
+
+int
+ecu_proc_fr(void *_state, uint8_t *out, const uint8_t *in, unsigned int in_len)
+{
+	struct osmo_ecu_fr_state *state = (struct osmo_ecu_fr_state *) _state;
+	bool backup = false;
+	bool bfi = true;
+	int i, rc;
+
+	assert(in_len == FR_CANON_LEN);
+
+	/* Check if a frame is BFI */
+	for (i = 1; i < in_len; i++) {
+		if (in[i] != 0x00) {
+			bfi = false;
+			break;
+		}
+	}
+
+	/* We have got a good frame, nothing to do */
+	if (!bfi) {
+		osmo_ecu_fr_reset(state, (uint8_t *) in);
+		memcpy(out, in, in_len);
+		return in_len;
+	}
+
+	/* Check if ECU state contains a backup frame */
+	for (i = 0; i < in_len; i++) {
+		if (state->frame_backup[i] != 0x00) {
+			backup = true;
+			break;
+		}
+	}
+
+	/* There is no back-up frame */
+	if (!backup) {
+		/* Copy BFI 'as-is' */
+		memcpy(out, in, in_len);
+		return in_len;
+	}
+
+	/* Attempt to perform error concealment */
+	rc = osmo_ecu_fr_conceal(state, out);
+	if (rc)
+		return rc;
+
+	return in_len;
+}