Diff: CRC7.cpp

Revision:

0:511d65ef1276

diff -r 000000000000 -r 511d65ef1276 CRC7.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CRC7.cpp	Mon Mar 03 19:34:13 2014 +0000
@@ -0,0 +1,46 @@
+/**
+ *    @file        CRC7.cpp
+ *    @author        Edward Wilson (edwilson1989@gmail.com)
+ *  @date         Dec 16, 2010
+ *  @brief        The CRC7 checksum code.
+ *
+ *
+ */
+
+#include "CRC7.h"
+
+CRC7::CRC7()
+{
+    GenerateCRCTable();
+
+}
+
+unsigned char CRC7::GetCRC(unsigned char val)
+{
+    int j;
+    for (j = 0; j < 8; j++) {
+        if (val & 1)
+            val ^= CRC7_POLY;
+        val >>= 1;
+    }
+    return val;
+}
+
+unsigned char CRC7::CRC(unsigned char message[], unsigned int length)
+{
+    unsigned char i, crc = 0;
+
+    for (i = 0; i < length; i++)
+        crc = CRCTable[crc ^ message[i]];
+    return crc;
+}
+
+void CRC7::GenerateCRCTable()
+{
+    int i;
+    // generate a table value for all 256 possible byte values
+    for (i = 0; i < 256; i++) {
+        CRCTable[i] = GetCRC(i);
+    }
+}
+