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+// User include file for libfec
+// Copyright 2004, 2014 Phil Karn, KA9Q
+// May be used under the terms of the GNU Lesser General Public License (LGPL)
+
+#ifndef _FEC_H_
+#define _FEC_H_
+
+// r=1/2 k=7 convolutional encoder polynomials
+// The NASA-DSN convention is to use V27POLYA inverted, then V27POLYB
+// The CCSDS/NASA-GSFC convention is to use V27POLYB, then V27POLYA inverted
+#define	V27POLYA	0x6d
+#define	V27POLYB	0x4f
+
+void *create_viterbi27(int len);
+int init_viterbi27(void *vp,int starting_state);
+int update_viterbi27_blk(void *vp,unsigned char sym[],int npairs);
+int chainback_viterbi27(void *vp, unsigned char *data,unsigned int nbits,unsigned int endstate);
+void delete_viterbi27(void *vp);
+
+// r=1/2 k=9 convolutional encoder polynomials
+#define	V29POLYA	0x1af
+#define	V29POLYB	0x11d
+
+void *create_viterbi29(int len);
+int init_viterbi29(void *vp,int starting_state);
+int update_viterbi29_blk(void *vp,unsigned char syms[],int nbits);
+int chainback_viterbi29(void *vp, unsigned char *data,unsigned int nbits,unsigned int endstate);
+void delete_viterbi29(void *vp);
+
+// r=1/3 k=9 convolutional encoder polynomials
+#define	V39POLYA	0x1ed
+#define	V39POLYB	0x19b
+#define	V39POLYC	0x127
+
+void *create_viterbi39(int len);
+int init_viterbi39(void *vp,int starting_state);
+int update_viterbi39_blk(void *vp,unsigned char syms[],int nbits);
+int chainback_viterbi39(void *vp, unsigned char *data,unsigned int nbits,unsigned int endstate);
+void delete_viterbi39(void *vp);
+
+// r=1/6 k=15 Cassini convolutional encoder polynomials without symbol inversion
+// dfree = 56
+// These bits may be left-right flipped from some textbook representations;
+// here I have the bits entering the shift register from the right (low) end
+
+// Some other spacecraft use the same code, but with the polynomials in a different order.
+// E.g., Mars Pathfinder and STEREO swap POLYC and POLYD. All use alternate symbol inversion.
+#define	V615POLYA	042631
+#define	V615POLYB	047245
+#define V615POLYC       056507
+#define V615POLYD       073363
+#define V615POLYE       077267
+#define V615POLYF       064537
+
+void *create_viterbi615(int len);
+int init_viterbi615(void *vp,int starting_state);
+int update_viterbi615_blk(void *vp,unsigned char *syms,int nbits);
+int chainback_viterbi615(void *vp, unsigned char *data,unsigned int nbits,unsigned int endstate);
+void delete_viterbi615(void *vp);
+
+// r=1/2 k=24 MCQLI-24 r=1/2 k=24 convolutional code for ISEE-3/ICE, launched 1978
+// Obviously this code was originally intended for sequential decoding, but here's
+// a monster Viterbi decoder for this code!
+// The ref gives the polynomials as 073353367 and 053353367 (octal)
+// Shortened from MCQLI-48
+#define V224POLY1   073665667
+#define V224POLY2   073665665
+#define G1FLIP  0
+#define G2FLIP  1           // Invert the second symbol
+
+void *create_viterbi224(int len);
+int init_viterbi224(void *p,int starting_state);
+int update_viterbi224_blk(void *p,const unsigned char *syms,int nbits);
+int chainback_viterbi224(void *p,unsigned char *data,unsigned int nbits,unsigned int endstate);
+void delete_viterbi224(void *p);
+
+// General purpose RS codec, 8-bit symbols
+void encode_rs_char(void *rs,unsigned char *data,unsigned char *parity);
+int decode_rs_char(void *rs,unsigned char *data,int *eras_pos,
+		   int no_eras);
+void *init_rs_char(int symsize,int gfpoly,
+		   int fcr,int prim,int nroots,
+		   int pad);
+void free_rs_char(void *rs);
+
+// General purpose RS codec, integer symbols
+void encode_rs_int(void *rs,int *data,int *parity);
+int decode_rs_int(void *rs,int *data,int *eras_pos,int no_eras);
+void *init_rs_int(int symsize,int gfpoly,int fcr,
+		  int prim,int nroots,int pad);
+void free_rs_int(void *rs);
+
+// CCSDS standard (255,223) RS codec with conventional (*not* dual-basis) representation
+void encode_rs_8(unsigned char *data,unsigned char *parity,int pad);
+int decode_rs_8(unsigned char *data,int *eras_pos,int no_eras,int pad);
+
+// CCSDS standard (255,223) RS codec with dual-basis symbol representation
+void encode_rs_ccsds(unsigned char *data,unsigned char *parity,int pad);
+int decode_rs_ccsds(unsigned char *data,int *eras_pos,int no_eras,int pad);
+
+// Tables to map from conventional->dual (Taltab) and dual->conventional (Tal1tab) bases
+extern unsigned char Taltab[],Tal1tab[];
+
+#endif /* _FEC_H_ */
+
+
+