--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgsmhr1/paramval_common.c	Sun Aug 25 18:42:27 2024 +0000
@@ -0,0 +1,90 @@
+/*
+ * The function implemented in this module examines an array of 18 codec
+ * parameters in the int16_t representation used in this library, and checks
+ * if the unused upper bits of each int16_t word are cleared as they should be.
+ * This function, or higher-level wrappers around it, should be used when
+ * reading from ETSI-format *.cod and *.dec files, to guard against reading
+ * garbage or wrong endian.
+ */
+
+#include <stdint.h>
+#include "tw_gsmhr.h"
+
+int gsmhr_check_common_params(const int16_t *params)
+{
+	/* common parameters for all modes */
+	if (params[0] & 0xFFE0)
+		return -1;
+	if (params[1] & 0xF800)
+		return -1;
+	if (params[2] & 0xFE00)
+		return -1;
+	if (params[3] & 0xFF00)
+		return -1;
+	if (params[4] & 0xFFFE)
+		return -1;
+	if (params[5] & 0xFFFC)
+		return -1;
+	if (params[5]) {
+		/* voiced modes */
+		/* subframe 1 */
+		if (params[6] & 0xFF00)
+			return -1;
+		if (params[7] & 0xFE00)
+			return -1;
+		if (params[8] & 0xFFE0)
+			return -1;
+		/* subframe 2 */
+		if (params[9] & 0xFFF0)
+			return -1;
+		if (params[10] & 0xFE00)
+			return -1;
+		if (params[11] & 0xFFE0)
+			return -1;
+		/* subframe 3 */
+		if (params[12] & 0xFFF0)
+			return -1;
+		if (params[13] & 0xFE00)
+			return -1;
+		if (params[14] & 0xFFE0)
+			return -1;
+		/* subframe 4 */
+		if (params[15] & 0xFFF0)
+			return -1;
+		if (params[16] & 0xFE00)
+			return -1;
+		if (params[17] & 0xFFE0)
+			return -1;
+	} else {
+		/* unvoiced mode */
+		/* subframe 1 */
+		if (params[6] & 0xFF80)
+			return -1;
+		if (params[7] & 0xFF80)
+			return -1;
+		if (params[8] & 0xFFE0)
+			return -1;
+		/* subframe 2 */
+		if (params[9] & 0xFF80)
+			return -1;
+		if (params[10] & 0xFF80)
+			return -1;
+		if (params[11] & 0xFFE0)
+			return -1;
+		/* subframe 3 */
+		if (params[12] & 0xFF80)
+			return -1;
+		if (params[13] & 0xFF80)
+			return -1;
+		if (params[14] & 0xFFE0)
+			return -1;
+		/* subframe 4 */
+		if (params[15] & 0xFF80)
+			return -1;
+		if (params[16] & 0xFF80)
+			return -1;
+		if (params[17] & 0xFFE0)
+			return -1;
+	}
+	return 0;
+}