[pcre] try to avoid null chars in log messages

src/ansi_scrubber.cc

@@ -53,6 +53,7 @@ void scrub_ansi_string(std::string &str, string_attrs_t &sa)
     pcrepp &   regex = ansi_regex();
     pcre_input pi(str);
 
+    replace(str.begin(), str.end(), '\0', ' ');
     while (regex.match(context, pi)) {
         pcre_context::capture_t *caps = context.all();
         struct line_range        lr;

src/pcrepp.hh

@@ -204,8 +204,8 @@ public:
         if (iter->c_begin == -1) {
             return "";
         }
-        return std::string(this->pi_string,
-                           iter->c_begin,
+        return std::string(&this->pi_string[iter->c_begin],
+                           0,
                            iter->length());
     };
 

test/test_pcrepp.cc

@@ -97,5 +97,12 @@ int main(int argc, char *argv[])
         assert(pi.get_substr(context["var1"]) == "123");
     }
 
+    {
+        pcre_context::capture cap(1, 4);
+        pcre_input pi("\0foo", 0, 4);
+
+        assert("foo" == pi.get_substr(&cap));
+    }
+
     return retval;
 }