Initial Commit

lib/wsprd/fano.h

@@ -0,0 +1,39 @@
+/*
+ This file is part of wsprd.
+ 
+ File name: fano.h
+
+ Description: Header file for sequential Fano decoder.
+
+ Copyright 1994, Phil Karn, KA9Q
+ Minor modifications by Joe Taylor, K1JT
+*/
+
+#ifndef FANO_H
+#define FANO_H
+
+int fano(unsigned int *metric, unsigned int *cycles, unsigned int *maxnp,
+	unsigned char *data,unsigned char *symbols, unsigned int nbits,
+	 int mettab[2][256],int delta,unsigned int maxcycles);
+
+int encode(unsigned char *symbols,unsigned char *data,unsigned int nbytes);
+
+extern unsigned char Partab[];
+
+/* Convolutional encoder macro. Takes the encoder state, generates
+ * a rate 1/2 symbol pair and stores it in 'sym'. The symbol generated from
+ * POLY1 goes into the 2-bit of sym, and the symbol generated from POLY2
+ * goes into the 1-bit.
+ */
+#define	ENCODE(sym,encstate){\
+unsigned long _tmp;\
+\
+_tmp = (encstate) & POLY1;\
+_tmp ^= _tmp >> 16;\
+(sym) = Partab[(_tmp ^ (_tmp >> 8)) & 0xff] << 1;\
+_tmp = (encstate) & POLY2;\
+_tmp ^= _tmp >> 16;\
+(sym) |= Partab[(_tmp ^ (_tmp >> 8)) & 0xff];\
+}
+
+#endif