Update README.md

[proxmark3-svn] / common / crc.c

diff --git a/common/crc.c b/common/crc.c
index 540ae668f9d32f9108cc6aa48890cca2e1ec4766..f9a15234ed951da5f95e739e2ebf7c2c150b4eb1 100644 (file)
--- a/common/crc.c
+++ b/common/crc.c
@@ -35,32 +35,24 @@ void crc_clear(crc_t *crc) {
                crc->state = reflect(crc->state, crc->order);
 }
 
-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
+void crc_update2(crc_t *crc, uint32_t data, int data_width){
+       
        if (crc->refin) 
-               indata = reflect(indata, data_width);
+               data = reflect(data, data_width);
        
        // Bring the next byte into the remainder.
-       crc->state ^= indata << (crc->order - data_width);
+       crc->state ^= data << (crc->order - data_width);
        
        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) ^ poly;
+                       crc->state = (crc->state << 1) ^ crc->polynom;
                else
                        crc->state = (crc->state << 1);
        }
-    return crc ^ model->xorout;
 }
 
-void crc_update2(crc_t *crc, uint32_t data, int data_width)
+void crc_update(crc_t *crc, uint32_t data, int data_width)
 {
        if (crc->refin) 
                data = reflect(data, data_width);
@@ -76,7 +68,6 @@ void crc_update2(crc_t *crc, uint32_t data, int data_width)
        }
 }
 
-
 uint32_t crc_finish(crc_t *crc) {
        uint32_t val = crc->state;
        if (crc->refout) val = reflect(val, crc->order);
@@ -104,7 +95,7 @@ uint32_t CRC8Maxim(uint8_t *buff, size_t size) {
        crc_t crc;
        crc_init_ref(&crc, 8, 0x31, 0, 0, TRUE, TRUE);  
        for ( int i=0; i < size; ++i)
-               crc_update(&crc, buff[i], 8);
+               crc_update2(&crc, buff[i], 8);
        return crc_finish(&crc);
 }
 
@@ -123,7 +114,7 @@ uint32_t CRC8Legic(uint8_t *buff, size_t size) {
        crc_t crc;
        crc_init_ref(&crc, 8, 0x63, 0x55, 0, TRUE, TRUE);
        for ( int i = 0; i < size; ++i)
-               crc_update(&crc, buff[i], 8);
+               crc_update2(&crc, buff[i], 8);
        return reflect(crc_finish(&crc), 8);
 }
 
@@ -147,7 +138,7 @@ uint32_t CRC16_DNP(uint8_t *buff, size_t size) {
        crc_t crc;
        crc_init_ref(&crc, 16, 0x3d65, 0, 0xffff, TRUE, TRUE);
        for ( int i=0; i < size; ++i)
-               crc_update(&crc, buff[i], 8);
+               crc_update2(&crc, buff[i], 8);
        
        return BSWAP_16(crc_finish(&crc));
 }