X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/bfe85f7ca97259256e8089349e1a462b6c7dbd00..af0b220756571bc8faf57a0c7b7389dd86a60376:/src/crc16.c

diff --git a/src/crc16.c b/src/crc16.c
index 37fb4ca7..d3a232ba 100644
--- a/src/crc16.c
+++ b/src/crc16.c
@@ -2,8 +2,9 @@
 
 /*      
  * Copyright 2001-2010 Georges Menie (www.menie.org)
- * Copyright 2010 Salvatore Sanfilippo (adapted to Redis coding style)
+ * Copyright 2010-2012 Salvatore Sanfilippo (adapted to Redis coding style)
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
@@ -28,7 +29,20 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-/* CRC16 implementation acording to CCITT standards */
+/* CRC16 implementation acording to CCITT standards.
+ *
+ * Note by @antirez: this is actually the XMODEM CRC 16 algorithm, using the
+ * following parameters:
+ *
+ * Name                       : "XMODEM", also known as "ZMODEM", "CRC-16/ACORN"
+ * Width                      : 16 bit
+ * Poly                       : 1021 (That is actually x^16 + x^12 + x^5 + 1)
+ * Initialization             : 0000
+ * Reflect Input byte         : False
+ * Reflect Output CRC         : False
+ * Xor constant to output CRC : 0000
+ * Output for "123456789"     : 31C3
+ */
 
 static const uint16_t crc16tab[256]= {
     0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,