From b5b0f4f0d231b2e99eb4451c7da10935359b0225 Mon Sep 17 00:00:00 2001
From: Nanosonde <2073569+nanosonde@users.noreply.github.com>
Date: Sat, 4 Jul 2020 12:08:41 +0200
Subject: [PATCH] cleanup

---
 examples/knx-linux/fdsk.cpp | 25 ++++++++++++++++---------
 examples/knx-linux/fdsk.h   |  2 +-
 examples/knx-linux/main.cpp |  4 +++-
 3 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/examples/knx-linux/fdsk.cpp b/examples/knx-linux/fdsk.cpp
index 6243718..8d9b28c 100644
--- a/examples/knx-linux/fdsk.cpp
+++ b/examples/knx-linux/fdsk.cpp
@@ -1,7 +1,6 @@
 #include "fdsk.h"
 
 #include <string.h>
-#include <stdio.h>
 
 // CRC-4 generator polynom: 10011 (x^4+x+1)
 const uint8_t FdskCalculator::crc4_tab[16] =
@@ -10,21 +9,29 @@ const uint8_t FdskCalculator::crc4_tab[16] =
     0xb, 0x8, 0xd, 0xe, 0x7, 0x4, 0x1, 0x2
 };
 
-void FdskCalculator::printFdsk(uint8_t* serialNumber, uint8_t* key)
+int FdskCalculator::snprintFdsk(char* str, int strSize, uint8_t* serialNumber, uint8_t* key)
 {
-    char* str = generateFdskString(serialNumber, key);
+    char* tmpStr = generateFdskString(serialNumber, key);
+    int written = 0;
 
-    uint8_t len = strlen(str);
-    printf("FDSK(len: %d): ", len);
     for (int i = 0; i < 36; i++)
     {
         if (((i % 6) == 0) && (i!=0))
-            printf("-");
-        printf("%c", str[i]);
+        {
+            *(str+written++) = '-';
+            if (written >= strSize-1)
+                break;
+        }
+        *(str+written++) = tmpStr[i];
+        if (written >= strSize-1)
+            break;
     }
-    printf("\n");
 
-    delete[] str;
+    *(str+written++) = '\0';
+
+    delete[] tmpStr;
+
+    return written;
 }
 
 char* FdskCalculator::generateFdskString(uint8_t* serialNumber, uint8_t* key)
diff --git a/examples/knx-linux/fdsk.h b/examples/knx-linux/fdsk.h
index 2655f69..560ba22 100644
--- a/examples/knx-linux/fdsk.h
+++ b/examples/knx-linux/fdsk.h
@@ -5,7 +5,7 @@
 class FdskCalculator
 {
   public:
-    void printFdsk(uint8_t* serialNumber, uint8_t* key);
+    int snprintFdsk(char* str, int strSize, uint8_t* serialNumber, uint8_t* key);
 
   private:
     char* generateFdskString(uint8_t* serialNumber, uint8_t* key);
diff --git a/examples/knx-linux/main.cpp b/examples/knx-linux/main.cpp
index a680b8d..2b96854 100644
--- a/examples/knx-linux/main.cpp
+++ b/examples/knx-linux/main.cpp
@@ -134,7 +134,9 @@ int main(int argc, char **argv)
     uint8_t key[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F};
 
     FdskCalculator calc;
-    calc.printFdsk(serialNumber, key);
+    char fdskString[42]; // 6 * 6 chars + 5 dashes + nullbyte = 42
+    calc.snprintFdsk(fdskString, sizeof(fdskString), serialNumber, key);
+    printf("FDSK: %s\n", fdskString);
 
     // Prevent swapping of this process
     struct sched_param sp;