Fixed a bug which could potentially occur when empty std::vector<char>

or std::vector<unsigned char> were serialized.

dlib/serialize.h

@@ -893,7 +893,8 @@ namespace dlib
         { 
             const unsigned long size = static_cast<unsigned long>(item.size());
             serialize(size,out); 
-            out.write(&item[0], item.size());
+            if (item.size() != 0)
+                out.write(&item[0], item.size());
         }
         catch (serialization_error& e)
         { throw serialization_error(e.info + "\n   while serializing object of type std::vector"); }
@@ -910,7 +911,8 @@ namespace dlib
             unsigned long size;
             deserialize(size,in); 
             item.resize(size);
-            in.read(&item[0], item.size());
+            if (item.size() != 0)
+                in.read(&item[0], item.size());
         }
         catch (serialization_error& e)
         { throw serialization_error(e.info + "\n   while deserializing object of type std::vector"); }
@@ -928,7 +930,8 @@ namespace dlib
         { 
             const unsigned long size = static_cast<unsigned long>(item.size());
             serialize(size,out); 
-            out.write((char*)&item[0], item.size());
+            if (item.size() != 0)
+                out.write((char*)&item[0], item.size());
         }
         catch (serialization_error& e)
         { throw serialization_error(e.info + "\n   while serializing object of type std::vector"); }
@@ -945,7 +948,8 @@ namespace dlib
             unsigned long size;
             deserialize(size,in); 
             item.resize(size);
-            in.read((char*)&item[0], item.size());
+            if (item.size() != 0)
+                in.read((char*)&item[0], item.size());
         }
         catch (serialization_error& e)
         { throw serialization_error(e.info + "\n   while deserializing object of type std::vector"); }

dlib/test/serialize.cpp

@@ -528,6 +528,14 @@ namespace
         {
             DLIB_TEST(a[i] == b[i]);
         }
+
+        std::vector<T> c;
+        sout.str("");
+        dlib::serialize(c, sout);
+        sin.str(sout.str());
+        dlib::deserialize(a, sin);
+        DLIB_TEST(a.size() == 0);
+        DLIB_TEST(c.size() == 0);
     }
 
     void test_vector_bool (