altos: improve FEC apis to reduce data copying

Integrate interleaving and whitening into encode and decode steps.
Add CRC checking function for receive.

Make ao_fec_test program round-trip the data and verify correctness.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 18 insertions, 8 deletions

diff --git a/src/core/ao_fec.h b/src/core/ao_fec.h
index d4f64b74..f3f55fa8 100644
--- a/src/core/ao_fec.h
+++ b/src/core/ao_fec.h
@@ -24,13 +24,23 @@
 #define AO_FEC_TRELLIS_TERMINATOR	0x0b
 #define AO_FEC_PREPARE_EXTRA		4
 
+extern const uint8_t ao_fec_whiten_table[];
+
 void
-ao_fec_dump_bytes(uint8_t *bytes, uint8_t len, char *name);
+ao_fec_dump_bytes(uint8_t *bytes, uint16_t len, char *name);
 
 uint16_t
 ao_fec_crc(uint8_t *bytes, uint8_t len);
 
 /*
+ * 'len' is the length of the original data; 'bytes'
+ * must  be four bytes longer than that, and the first
+ * two after 'len' must be the received crc
+ */
+uint8_t
+ao_fec_check_crc(uint8_t *bytes, uint8_t len);
+
+/*
  * Append CRC and terminator bytes, returns resulting length.
  * 'out' must be at least len + AO_FEC_PREPARE_EXTRA bytes long
  */
@@ -46,18 +56,12 @@ void
 ao_fec_whiten(uint8_t *in, uint8_t len, uint8_t *out);
 
 /*
- * Encode data. 'out' must be len*2 bytes long
+ * Encode and interleave data. 'out' must be len*2 bytes long
  */
 uint8_t
 ao_fec_encode(uint8_t *in, uint8_t len, uint8_t *out);
 
 /*
- * Interleave data. 'out' must be 'len' bytes long
- */
-uint8_t
-ao_fec_interleave(uint8_t *in, uint8_t len, uint8_t *out);
-
-/*
  * Decode data. 'in' is one byte per bit, soft decision
  * 'out' must be len/8 bytes long
  */
@@ -65,4 +69,10 @@ ao_fec_interleave(uint8_t *in, uint8_t len, uint8_t *out);
 uint8_t
 ao_fec_decode(uint8_t *in, uint16_t in_len, uint8_t *out);
 
+/*
+ * Interleave data packed in bytes. 'out' must be 'len' bytes long.
+ */
+uint16_t
+ao_fec_interleave_bytes(uint8_t *in, uint16_t len, uint8_t *out);
+
 #endif /* _AO_FEC_H_ */