--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/dhf_check.c	Sun May 05 21:59:18 2024 +0000
@@ -0,0 +1,42 @@
+/*
+ * This module implements the DHF checking function.
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include "tw_amr.h"
+#include "typedef.h"
+#include "namespace.h"
+#include "bitno.h"
+
+static const Word16 * const dhf_per_mode[8] = {
+	amr_dhf_mr475,
+	amr_dhf_mr515,
+	amr_dhf_mr59,
+	amr_dhf_mr67,
+	amr_dhf_mr74,
+	amr_dhf_mr795,
+	amr_dhf_mr102,
+	amr_dhf_mr122
+};
+
+int amr_check_dhf(const struct amr_param_frame *frame, int first_sub_only)
+{
+	const Word16 *table;
+	Word16 nparam;
+
+	if (frame->type != RX_SPEECH_GOOD)
+		return 0;
+	if ((frame->mode & 0x87) == 0x87)
+		table = amr_dhf_gsmefr;
+	else
+		table = dhf_per_mode[frame->mode & 7];
+	if (first_sub_only)
+		nparam = prmnofsf[frame->mode & 7];
+	else
+		nparam = prmno[frame->mode & 7];
+	if (memcmp(frame->param, table, nparam * sizeof(int16_t)))
+		return 0;
+	else
+		return 1;
+}