--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgsmhr1/unpack_frame.c	Sat Jun 15 05:33:35 2024 +0000
@@ -0,0 +1,68 @@
+/*
+ * This module holds our gsmhr_unpack_ts101318() function: unpacking a single
+ * GSM-HR codec frame from TS 101 318 packed format into the codec's native
+ * array of parameters.
+ */
+
+#include <stdint.h>
+#include "tw_gsmhr.h"
+
+void gsmhr_unpack_ts101318(const uint8_t *payload, int16_t *params)
+{
+	const uint8_t *c = payload;
+
+	params[0]  = (*c >> 3) & 0x1F;
+	params[1]  = (*c++ & 0x7) << 8;
+	params[1] |= *c++;
+	params[2]  = (*c++ & 0xFF) << 1;
+	params[2] |= (*c >> 7) & 0x1;
+	params[3]  = (*c++ & 0x7F) << 1;
+	params[3] |= (*c >> 7) & 0x1;
+	params[4]  = (*c >> 6) & 0x1;
+	params[5]  = (*c >> 4) & 0x3;
+	if (params[5]) {
+		/* voiced modes */
+		params[6]  = (*c++ & 0xF) << 4;
+		params[6] |= (*c >> 4) & 0xF;
+		params[7]  = (*c++ & 0xF) << 5;
+		params[7] |= (*c >> 3) & 0x1F;
+		params[8]  = (*c++ & 0x7) << 2;
+		params[8] |= (*c >> 6) & 0x3;
+		params[9]  = (*c >> 2) & 0xF;
+		params[10]  = (*c++ & 0x3) << 7;
+		params[10] |= (*c >> 1) & 0x7F;
+		params[11]  = (*c++ & 0x1) << 4;
+		params[11] |= (*c >> 4) & 0xF;
+		params[12]  = *c++ & 0xF;
+		params[13]  = (*c++ & 0xFF) << 1;
+		params[13] |= (*c >> 7) & 0x1;
+		params[14]  = (*c >> 2) & 0x1F;
+		params[15]  = (*c++ & 0x3) << 2;
+		params[15] |= (*c >> 6) & 0x3;
+		params[16]  = (*c++ & 0x3F) << 3;
+		params[16] |= (*c >> 5) & 0x7;
+		params[17]  = *c++ & 0x1F;
+	} else {
+		/* unvoiced modes */
+		params[6]  = (*c++ & 0xF) << 3;
+		params[6] |= (*c >> 5) & 0x7;
+		params[7]  = (*c++ & 0x1F) << 2;
+		params[7] |= (*c >> 6) & 0x3;
+		params[8]  = (*c >> 1) & 0x1F;
+		params[9]  = (*c++ & 0x1) << 6;
+		params[9] |= (*c >> 2) & 0x3F;
+		params[10]  = (*c++ & 0x3) << 5;
+		params[10] |= (*c >> 3) & 0x1F;
+		params[11]  = (*c++ & 0x7) << 2;
+		params[11] |= (*c >> 6) & 0x3;
+		params[12]  = (*c++ & 0x3F) << 1;
+		params[12] |= (*c >> 7) & 0x1;
+		params[13]  = *c++ & 0x7F;
+		params[14]  = (*c >> 3) & 0x1F;
+		params[15]  = (*c++ & 0x7) << 4;
+		params[15] |= (*c >> 4) & 0xF;
+		params[16]  = (*c++ & 0xF) << 3;
+		params[16] |= (*c >> 5) & 0x7;
+		params[17]  = *c++ & 0x1F;
+	}
+}