Add "seed" capabilities to crc16_x25_ccitt (now crc16_x25_ccitt_seed) so we can remove CRC algorithm calculation in packet-assa_r3.c.

Change-Id: I3143800f6ff922a309f5506d9acbc2c4293363b7
Reviewed-on: https://code.wireshark.org/review/7490
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>
Petri-Dish: Jeff Morriss <jeff.morriss.ws@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 3 insertions, 59 deletions

diff --git a/epan/dissectors/packet-assa_r3.c b/epan/dissectors/packet-assa_r3.c
index 3d69586c1c..536605c39d 100644
--- a/epan/dissectors/packet-assa_r3.c
+++ b/epan/dissectors/packet-assa_r3.c
@@ -28,6 +28,7 @@
 
 #include <epan/packet.h>
 #include <epan/expert.h>
+#include <epan/crc16-tvb.h>
 #include "packet-tcp.h"
 
 void proto_register_r3(void);
@@ -3543,60 +3544,6 @@ static void (*r3upstreammfgfield_dissect []) (tvbuff_t *tvb, guint32 start_offse
 
 /*
  * ***************************************************************************
- *
- *  Cannot use wsutil/crc routines as ccitt-x25 uses a starting value of 0xffff
- *  and we use 0x0000 (legacy compatibility).  If an override method to set
- *  the starting value existed, these could be replaced.
- */
-static const guint16 ccitt_16 [256] =
-{
-  0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
-  0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
-  0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
-  0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
-  0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
-  0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
-  0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
-  0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
-  0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
-  0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
-  0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
-  0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
-  0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
-  0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
-  0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
-  0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
-  0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
-  0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
-  0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
-  0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
-  0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
-  0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
-  0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
-  0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
-  0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
-  0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
-  0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
-  0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
-  0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
-  0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
-  0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
-  0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
-};
-
-static guint16
-utilCrcCalculate (const void *ptr, guint16 len, guint16 crc)
-{
-  const guint8 *p = (const guint8 *) ptr;
-
-  while (len--)
-    crc = (guint16) ((crc << 8) ^ ccitt_16 [(crc >> 8) ^ *p++]);
-
-  return crc;
-}
-
-/*
- * ***************************************************************************
  */
 static void
 dissect_serialnumber (tvbuff_t *tvb, guint32 start_offset, guint32 length _U_, packet_info *pinfo _U_, proto_tree *tree, int hf_index)
@@ -5977,10 +5924,7 @@ dissect_r3_cmd_downloadfirmware (tvbuff_t *tvb, guint32 start_offset, guint32 le
 
   packetCRC = tvb_get_letohs (payload_tvb, cmdLen - 2 - 2);
 
-  if ((calculatedCRC = utilCrcCalculate (tvb_get_ptr (payload_tvb, 0, cmdLen - 2 - 2),
-                                         cmdLen - 2,
-                                         0x0000))
-      == packetCRC)
+  if ((calculatedCRC = crc16_r3_ccitt_tvb(payload_tvb, 0, cmdLen - 2 - 2)) == packetCRC)
     proto_tree_add_uint_format_value(dlfw_tree, hf_r3_firmwaredownload_crc, payload_tvb,
                                 cmdLen - 2 - 2, 2,
                                 packetCRC, "0x%04x (correct)", packetCRC);
@@ -6709,7 +6653,7 @@ dissect_r3_packet (tvbuff_t *tvb, packet_info *pinfo, proto_tree *r3_tree)
     guint32     packetXor     = tvb_get_guint8 (tvb, offset + 2);
     guint32     calculatedCRC;
 
-    if ((calculatedCRC = utilCrcCalculate (tvb_get_ptr (tvb, 1, packetLen - 3), packetLen - 3, 0x0000)) == packetCRC)
+    if ((calculatedCRC = crc16_r3_ccitt_tvb(tvb, 1, packetLen - 3)) == packetCRC)
       proto_tree_add_uint_format_value(tail_tree, hf_r3_crc, tvb, offset, 2, packetCRC, "0x%04x (correct)", packetCRC);
     else
     {