Update README.md

[proxmark3-svn] / common / iso15693tools.c

diff --git a/common/iso15693tools.c b/common/iso15693tools.c
index 6d8ae5b135c9c7390359741ae84666cb0de8eb99..56b2fdb0af9f329daf59dfe1b802208bc9f5058d 100644 (file)
--- a/common/iso15693tools.c
+++ b/common/iso15693tools.c
@@ -7,26 +7,35 @@
 //-----------------------------------------------------------------------------
 
 
-#include "proxmark3.h"
+#include "iso15693tools.h"
+
+#include <stddef.h>
 #include <stdint.h>
-#include <stdlib.h>
-//#include "iso15693tools.h"
+#ifdef ON_DEVICE
+#include "printf.h"
+#else
+#include <stdio.h>
+#endif
+
+
+#define ISO15693_CRC_PRESET  (uint16_t)0xFFFF
+#define ISO15693_CRC_POLY    (uint16_t)0x8408
+
 
 // The CRC as described in ISO 15693-Part 3-Annex C
-//     v       buffer with data
-//             n       length
-//     returns crc as 16bit value
-uint16_t Iso15693Crc(uint8_t *v, int n)
-{
+//    v   buffer with data
+//    n   length
+//  returns crc as 16bit value
+uint16_t Iso15693Crc(uint8_t *v, int n) {
        uint32_t reg;
        int i, j;
 
-       reg = 0xffff;
-       for(i = 0; i < n; i++) {
+       reg = ISO15693_CRC_PRESET;
+       for (i = 0; i < n; i++) {
                reg = reg ^ ((uint32_t)v[i]);
                for (j = 0; j < 8; j++) {
                        if (reg & 0x0001) {
-                               reg = (reg >> 1) ^ 0x8408;
+                               reg = (reg >> 1) ^ ISO15693_CRC_POLY;
                        } else {
                                reg = (reg >> 1);
                        }
@@ -37,31 +46,50 @@ uint16_t Iso15693Crc(uint8_t *v, int n)
 }
 
 // adds a CRC to a dataframe
-//     req[]   iso15963 frame without crc
-//             n       length without crc
+//    req[]   iso15963 frame without crc
+//    n       length without crc
 // returns the new length of the dataframe.
 int Iso15693AddCrc(uint8_t *req, int n) {
-       uint16_t crc=Iso15693Crc(req,n);
+       uint16_t crc = Iso15693Crc(req, n);
        req[n] = crc & 0xff;
        req[n+1] = crc >> 8;
-       return n+2;
+       return n + 2;
 }
 
 
-int sprintf(char *str, const char *format, ...);
-
 // returns a string representation of the UID
 // UID is transmitted and stored LSB first, displayed MSB first
-//             target    char* buffer, where to put the UID, if NULL a static buffer is returned
-//             uid[]           the UID in transmission order
-//     return: ptr to string
-char* Iso15693sprintUID(char *target,uint8_t *uid) {
-  static char tempbuf[9]="";
-  if (target==NULL) target=tempbuf;
-  sprintf(target,"%02hX%02hX%02hX%02hX%02hX%02hX%02hX%02hX",
-                               uid[7],uid[6],uid[5],uid[4],uid[3],uid[2],uid[1],uid[0]);
-  return target;
+//    target    char* buffer, where to put the UID, if NULL a static buffer is returned
+//    uid[]     the UID in transmission order
+//    return:   ptr to string
+char* Iso15693sprintUID(char *target, uint8_t *uid) {
+       static char tempbuf[2*8+1] = "";
+       if (target == NULL) target = tempbuf;
+       sprintf(target, "%02X%02X%02X%02X%02X%02X%02X%02X", uid[7], uid[6], uid[5], uid[4], uid[3], uid[2], uid[1], uid[0]);
+       return target;
 }
 
 
+uint16_t iclass_crc16(uint8_t *data_p, unsigned short length) {
+       unsigned char i;
+       unsigned int data;
+       uint16_t crc = ISO15693_CRC_PRESET;
+
+       if (length == 0)
+               return (~crc);
+
+       do {
+               for (i = 0, data = 0xff & *data_p++; i < 8; i++, data >>= 1) {
+                       if ((crc & 0x0001) ^ (data & 0x0001))
+                               crc = (crc >> 1) ^ ISO15693_CRC_POLY;
+                       else  crc >>= 1;
+               }
+       } while (--length);
+
+       crc = ~crc;
+       data = crc;
+       crc = (crc << 8) | (data >> 8 & 0xff);
+       crc = crc ^ 0x0BC3;
+       return (crc);
+}