Adds nfc_free() function to freed allocated buffers

Fixes issue 228 (Thanks to Alex Lian)

include/nfc/nfc.h

@@ -131,6 +131,7 @@ extern  "C" {
   NFC_EXPORT void iso14443a_crc_append(uint8_t *pbtData, size_t szLen);
   NFC_EXPORT uint8_t *iso14443a_locate_historical_bytes(uint8_t *pbtAts, size_t szAts, size_t *pszTk);
 
+  NFC_EXPORT void nfc_free(void *p);
   NFC_EXPORT const char *nfc_version(void);
   NFC_EXPORT int nfc_device_get_information_about(nfc_device *pnd, char **buf);
 

libnfc/nfc.c

@@ -1168,6 +1168,17 @@ nfc_version(void)
 #endif // GIT_REVISION
 }
 
+/** @ingroup misc
+ * @brief Free buffer allocated by libnfc
+ *
+ * @param pointer on buffer that need to be freed
+ */
+void
+nfc_free(void *p)
+{
+  free(p);
+}
+
 /** @ingroup misc
  * @brief Print information about NFC device
  * @return Upon successful return, this function returns the number of characters printed (excluding the null byte used to end output to strings), otherwise returns libnfc's error code (negative value)
@@ -1255,7 +1266,7 @@ str_nfc_modulation_type(const nfc_modulation_type nmt)
  * @param nt \a nfc_target struct to print
  * @param buf pointer where string will be allocated, then nfc target information printed
  *
- * @warning *buf must be freed.
+ * @warning *buf must be freed using nfc_free()
 */
 int
 str_nfc_target(char **buf, const nfc_target nt, bool verbose)

utils/nfc-scan-device.c

@@ -125,7 +125,7 @@ main(int argc, const char *argv[])
       if (verbose) {
         if (nfc_device_get_information_about(pnd, &strinfo) >= 0) {
           printf("%s", strinfo);
-          free(strinfo);
+          nfc_free(strinfo);
         }
       }
       nfc_close(pnd);

utils/nfc-utils.c

@@ -120,5 +120,5 @@ print_nfc_target(const nfc_target nt, bool verbose)
   char *s;
   str_nfc_target(&s, nt, verbose);
   printf("%s", s);
-  free(s);
+  nfc_free(s);
 }