CHG: a select_legic function with structs and stuff and

[proxmark3-svn] / common / crc.c

diff --git a/common/crc.c b/common/crc.c
index 2f11f5f45f6c97386ffb6a595b014b05bd7a3e3b..540ae668f9d32f9108cc6aa48890cca2e1ec4766 100644 (file)
--- a/common/crc.c
+++ b/common/crc.c
@@ -29,6 +29,7 @@ void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, u
 }
 
 void crc_clear(crc_t *crc) {
+       
        crc->state = crc->initial_value & crc->mask;
        if (crc->refin) 
                crc->state = reflect(crc->state, crc->order);
@@ -36,26 +37,33 @@ void crc_clear(crc_t *crc) {
 
 void crc_update(crc_t *crc, uint32_t indata, int data_width){
 
+       uint32_t poly = crc->polynom;   
+
+       // if requested, return the initial CRC */
+    if (indata == 0)
+        return crc->initial_value;
+               
        //reflected
-       if (crc->refin) indata = reflect(indata, data_width);
+       if (crc->refin) 
+               indata = reflect(indata, data_width);
        
        // Bring the next byte into the remainder.
        crc->state ^= indata << (crc->order - data_width);
        
-       for( uint8_t bit = data_width; bit > 0; --bit) {
-               
-               
+       for( uint8_t bit = data_width; bit > 0; --bit) {                
                 // Try to divide the current data bit.
                if (crc->state & crc->topbit)
-                       crc->state = (crc->state << 1) ^ crc->polynom;
+                       crc->state = (crc->state << 1) ^ poly;
                else
                        crc->state = (crc->state << 1);
        }
+    return crc ^ model->xorout;
 }
 
 void crc_update2(crc_t *crc, uint32_t data, int data_width)
 {
-       if (crc->refin) data = reflect(data, data_width);
+       if (crc->refin) 
+               data = reflect(data, data_width);
        
        int i;
        for(i=0; i<data_width; i++) {