Clean up the CRC-10 code.

Have the wsutil routine just accumulate the stuff from the buffer handed
to us.  Have the IUUP dissector deal with the extra stuff.  Add a
update_crc10_by_bytes_tvb() routine, which is passed a tvbuff, offset,
and length, and use that rather than using tvb_get_ptr() in dissectors.

Change-Id: Iadd0823c764080e60d1339abb94d2e19150eabfe
Reviewed-on: https://code.wireshark.org/review/3509
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 7 insertions, 15 deletions

diff --git a/wsutil/crc10.c b/wsutil/crc10.c
index 9f04d93c04..17d6f1a291 100644
--- a/wsutil/crc10.c
+++ b/wsutil/crc10.c
@@ -69,25 +69,17 @@ static const guint16 byte_crc10_table[256] = {
 	0x021e, 0x002d, 0x004b, 0x0278, 0x0087, 0x02b4, 0x02d2, 0x00e1
 };
 
-/* update the data block's CRC-10 remainder one byte at a time */
-guint16 update_crc10_by_bytes(guint16 crc10, const guint8 *data_blk_ptr,
-					  int data_blk_size)
+/* Update the data block's CRC-10 remainder one byte at a time */
+guint16
+update_crc10_by_bytes(guint16 crc10_accum, const guint8 *data_blk_ptr,
+                      int data_blk_size)
 {
     register int i;
-    guint16 crc10_accum = 0;
 
     for (i = 0;  i < data_blk_size; i++) {
-		crc10_accum = ((crc10_accum << 8) & 0x3ff)
-		^ byte_crc10_table[( crc10_accum >> 2) & 0xff]
-		^ *data_blk_ptr++;
+        crc10_accum = ((crc10_accum << 8) & 0x3ff)
+            ^ byte_crc10_table[( crc10_accum >> 2) & 0xff]
+            ^ *data_blk_ptr++;
     }
-    crc10_accum = ((crc10_accum << 8) & 0x3ff)
-		^ byte_crc10_table[( crc10_accum >> 2) & 0xff]
-		^ (crc10>>2);
-    crc10_accum = ((crc10_accum << 8) & 0x3ff)
-		^ byte_crc10_table[( crc10_accum >> 2) & 0xff]
-		^ ((crc10<<6) & 0xFF);
-
     return crc10_accum;
 }
-