1 files changed, 47 insertions, 0 deletions
diff --git a/gsm-receiver/src/lib/decoder/interleave.c b/gsm-receiver/src/lib/decoder/interleave.c
new file mode 100644
index 0000000..7b45927
--- /dev/null
+++ b/gsm-receiver/src/lib/decoder/interleave.c
@@ -0,0 +1,47 @@
+//TODO: this file shouldn't be part of the GSM Receiver
+#include <stdlib.h>
+#include <stdio.h>
+#include "interleave.h"
+
+int
+interleave_init(INTERLEAVE_CTX *ictx, int size, int block_size)
+{
+	ictx->trans_size = size;
+	ictx->trans = (unsigned short *)malloc(size * sizeof *ictx->trans);
+
+//	DEBUGF("size: %d\n", size);
+//	DEBUGF("Block size: %d\n", block_size);
+	int j, k, B;
+	for (k = 0; k < size; k++)
+	{
+		B = k % 4;
+		j = 2 * ((49 * k) % 57) + ((k % 8) / 4);
+		ictx->trans[k] = B * block_size + j;
+		/* Mapping: pos1 goes to pos2: pos1 -> pos2 */
+//		DEBUGF("%d -> %d\n", ictx->trans[k], k);
+	}
+//	exit(0);
+	return 0;
+}
+
+int
+interleave_deinit(INTERLEAVE_CTX *ictx)
+{
+	if (ictx->trans != NULL)
+	{
+		free(ictx->trans);
+		ictx->trans = NULL;
+	}
+
+	return 0;
+}
+
+void
+interleave_decode(INTERLEAVE_CTX *ictx, unsigned char *dst, unsigned char *src)
+{
+
+	int k;
+	for (k = 0; k < ictx->trans_size; k++)
+		dst[k] = src[ictx->trans[k]];
+}
+