# HG changeset patch
# User Mychaela Falconia <falcon@freecalypso.org>
# Date 1726778110 0
# Node ID c7b1e796e91bbef03901c8dc766f015d20fd8408
# Parent  96c4ed5529bfd403d7d84ac72dd228f6bcf1626f
libgsmfr2 TFO: implement main entry point function

diff -r 96c4ed5529bf -r c7b1e796e91b libgsmfr2/Makefile
--- a/libgsmfr2/Makefile	Thu Sep 19 20:15:54 2024 +0000
+++ b/libgsmfr2/Makefile	Thu Sep 19 20:35:10 2024 +0000
@@ -2,8 +2,8 @@
 	enc_homing.o enc_main.o enc_wrap.o full_dec.o full_dec_wrap.o \
 	long_term.o lpc.o pack_frame.o pack_frame2.o pp_bad.o pp_good.o \
 	pp_homing.o pp_state.o preprocess.o prng.o rpe.o short_term.o \
-	sidclass.o silence_frame.o table.o unpack_frame.o unpack_frame2.o \
-	xmaxc_mean.o
+	sidclass.o silence_frame.o table.o tfo_main.o unpack_frame.o \
+	unpack_frame2.o xmaxc_mean.o
 HDRS=	ed_internal.h ed_state.h pp_internal.h pp_state.h tw_gsmfr.h typedef.h
 LIB=	libgsmfr2.a
 
diff -r 96c4ed5529bf -r c7b1e796e91b libgsmfr2/tfo_main.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgsmfr2/tfo_main.c	Thu Sep 19 20:35:10 2024 +0000
@@ -0,0 +1,54 @@
+/*
+ * This module implements a wrapper around the main processing functions
+ * of our Rx DTX or TFO preprocessor, handling RTP input per TW-TS-001.
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include "tw_gsmfr.h"
+
+int gsmfr_tfo_xfrm_main(struct gsmfr_preproc_state *st, const uint8_t *rtp_pl,
+			unsigned rtp_pl_len, uint8_t *out)
+{
+	switch (rtp_pl_len) {
+	case 0:
+		/* BFI-no-data, but not an invalid RTP input per se */
+		gsmfr_preproc_bfi(st, 0, out);
+		return 0;
+	case 1:
+		if ((rtp_pl[0] & 0xF6) != 0xE6)
+			goto bad_rtp_input;
+		/* TW-TS-001 No_Data frame */
+		gsmfr_preproc_bfi(st, rtp_pl[0] & 1, out);
+		return 0;
+	case GSMFR_RTP_FRAME_LEN:
+		if ((rtp_pl[0] & 0xF0) != 0xD0)
+			goto bad_rtp_input;
+		/* basic RTP format */
+		memcpy(out, rtp_pl, GSMFR_RTP_FRAME_LEN);
+		gsmfr_preproc_good_frame_hm(st, out);
+		return 0;
+	case GSMFR_RTP_FRAME_LEN+1:
+		if ((rtp_pl[0] & 0xF4) != 0xE0)
+			goto bad_rtp_input;
+		if ((rtp_pl[1] & 0xF0) != 0xD0)
+			goto bad_rtp_input;
+		/* extended RTP format (TW-TS-001) */
+		if (rtp_pl[0] & 0x02)
+			gsmfr_preproc_bfi_bits(st, rtp_pl + 1, rtp_pl[0] & 1,
+						out);
+		else {
+			memcpy(out, rtp_pl + 1, GSMFR_RTP_FRAME_LEN);
+			gsmfr_preproc_good_frame_hm(st, out);
+		}
+		return 0;
+	default:
+	bad_rtp_input:
+		/*
+		 * Treat it like BFI-no-data, and tell the caller
+		 * that we received an invalid RTP payload.
+		 */
+		gsmfr_preproc_bfi(st, 0, out);
+		return -1;
+	}
+}