X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/1801456ede26acf58301412c8f3a5c01f1e9cd8f..c3963755b7bdb05523e694fbecca4dca2ad0112b:/common/iso15693tools.c

diff --git a/common/iso15693tools.c b/common/iso15693tools.c
index add0ba69..0f7a250b 100644
--- a/common/iso15693tools.c
+++ b/common/iso15693tools.c
@@ -12,6 +12,9 @@
 #include <stdlib.h>
 //#include "iso15693tools.h"
 
+#define POLY 0x8408
+
+
 // The CRC as described in ISO 15693-Part 3-Annex C
 // 	v	buffer with data
 //		n	length
@@ -63,5 +66,31 @@ char* Iso15693sprintUID(char *target,uint8_t *uid) {
   return target;
 }
 
+unsigned short iclass_crc16(char *data_p, unsigned short length)
+{
+      unsigned char i;
+      unsigned int data;
+      unsigned int crc = 0xffff;
+
+      if (length == 0)
+            return (~crc);
+
+      do
+      {
+            for (i=0, data=(unsigned int)0xff & *data_p++;
+                 i < 8; 
+                 i++, data >>= 1)
+            {
+                  if ((crc & 0x0001) ^ (data & 0x0001))
+                        crc = (crc >> 1) ^ POLY;
+                  else  crc >>= 1;
+            }
+      } while (--length);
 
+      crc = ~crc;
+      data = crc;
+      crc = (crc << 8) | (data >> 8 & 0xff);
+      crc = crc ^ 0xBC3;
+      return (crc);
+}