--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgsmfr2/unpack_frame2.c	Fri Apr 12 23:29:18 2024 +0000
@@ -0,0 +1,51 @@
+/*
+ * This module holds our gsmfr_unpack_to_array() function: a drop-in
+ * replacement for gsm_explode() from classic libgsm.
+ */
+
+#include <stdint.h>
+#include "tw_gsmfr.h"
+
+void gsmfr_unpack_to_array(const uint8_t *frame, int16_t *params)
+{
+	const uint8_t *c = frame;
+	unsigned sub;
+
+	params[0]  = (*c++ & 0xF) << 2;
+	params[0] |= (*c >> 6) & 0x3;
+	params[1]  = *c++ & 0x3F;
+	params[2]  = (*c >> 3) & 0x1F;
+	params[3]  = (*c++ & 0x7) << 2;
+	params[3] |= (*c >> 6) & 0x3;
+	params[4]  = (*c >> 2) & 0xF;
+	params[5]  = (*c++ & 0x3) << 2;
+	params[5] |= (*c >> 6) & 0x3;
+	params[6]  = (*c >> 3) & 0x7;
+	params[7]  = *c++ & 0x7;
+	params += 8;
+	for (sub = 0; sub < 4; sub++) {
+		params[0]  = (*c >> 1) & 0x7F;
+		params[1]  = (*c++ & 0x1) << 1;
+		params[1] |= (*c >> 7) & 0x1;
+		params[2]  = (*c >> 5) & 0x3;
+		params[3]  = (*c++ & 0x1F) << 1;
+		params[3] |= (*c >> 7) & 0x1;
+		params[4]  = (*c >> 4) & 0x7;
+		params[5]  = (*c >> 1) & 0x7;
+		params[6]  = (*c++ & 0x1) << 2;
+		params[6] |= (*c >> 6) & 0x3;
+		params[7]  = (*c >> 3) & 0x7;
+		params[8]  = *c++ & 0x7;
+		params[9]  = (*c >> 5) & 0x7;
+		params[10]  = (*c >> 2) & 0x7;
+		params[11]  = (*c++ & 0x3) << 1;
+		params[11] |= (*c >> 7) & 0x1;
+		params[12]  = (*c >> 4) & 0x7;
+		params[13]  = (*c >> 1) & 0x7;
+		params[14]  = (*c++ & 0x1) << 2;
+		params[14] |= (*c >> 6) & 0x3;
+		params[15]  = (*c >> 3) & 0x7;
+		params[16]  = *c++ & 0x7;
+		params += 17;
+	}
+}