1 files changed, 8 insertions, 6 deletions

diff --git a/misc.cc b/misc.cc
index 5d7c387..9b339cd 100644
--- a/misc.cc
+++ b/misc.cc
@@ -4,25 +4,27 @@
 #include "inttypes.h"
 #include <cstdlib>
 #include <cstring>
-#include <cassert>
+#include "LibraryException.h"
 
 namespace nitrokey {
 namespace misc {
 
 std::vector<uint8_t> hex_string_to_byte(const char* hexString){
+    const size_t big_string_size = 256; //arbitrary 'big' number
     const size_t s_size = strlen(hexString);
-    const size_t d_size = (s_size+1)/2; // add 1 for odd, ignore for even
-    assert(s_size%2==0);
-    assert(s_size<256); //arbitrary 'big' number
+    const size_t d_size = s_size/2;
+    if (s_size%2!=0 || s_size==0 || s_size>big_string_size){
+        throw InvalidHexString(0);
+    }
     auto data = std::vector<uint8_t>(d_size, 0);
 
     char buf[2];
     for(int i=0; i<s_size; i++){
 
         char c = hexString[i];
-        bool char_from_range = ('0' <= c && c <='9' || 'A' <= c && c <= 'F' || 'a' <= c && c<= 'f');
+        bool char_from_range = (('0' <= c && c <='9') || ('A' <= c && c <= 'F') || ('a' <= c && c<= 'f'));
         if (!char_from_range){
-            return {};
+            throw InvalidHexString(c);
         }
         buf[i%2] = c;
         if (i%2==1){