Use !s.empty() instead of s != ""

The use of "" requires constructing a std::string or dstringt, and then a
string comparison. empty() is just an integer comparison (both for std::string
an dstringt).

Author: tautschnig

jbmc/src/java_bytecode/java_entry_point.cpp

@@ -517,7 +517,7 @@ main_function_resultt get_main_symbol(
   messaget message(message_handler);
 
   // find main symbol
-  if(config.main!="")
+  if(!config.main.empty())
   {
     // Add java:: prefix
     std::string main_identifier="java::"+config.main;

jbmc/unit/java-testing-utils/require_type.cpp

@@ -452,7 +452,7 @@ require_type::require_struct_tag(const typet &type, const irep_idt &identifier)
 {
   REQUIRE(type.id() == ID_struct_tag);
   const struct_tag_typet &result = to_struct_tag_type(type);
-  if(identifier != "")
+  if(!identifier.empty())
   {
     REQUIRE(result.get_identifier() == identifier);
   }

src/analyses/invariant_set.cpp

@@ -64,8 +64,7 @@ bool inv_object_storet::get(const exprt &expr, unsigned &n)
 unsigned inv_object_storet::add(const exprt &expr)
 {
   std::string s=build_string(expr);
-
-  assert(s!="");
+  CHECK_RETURN(!s.empty());
 
   mapt::number_type n=map.number(s);
 

src/ansi-c/ansi_c_entry_point.cpp

@@ -123,7 +123,7 @@ bool ansi_c_entry_point(
   irep_idt main_symbol;
 
   // find main symbol
-  if(config.main!="")
+  if(!config.main.empty())
   {
     std::list<irep_idt> matches;
 

src/ansi-c/expr2c.cpp

@@ -330,7 +330,7 @@ std::string expr2ct::convert_rec(
     std::string dest=q+"union";
 
     const irep_idt &tag=union_type.get_tag();
-    if(tag!="")
+    if(!tag.empty())
       dest+=" "+id2string(tag);
 
     if(!union_type.is_incomplete())
@@ -414,7 +414,7 @@ std::string expr2ct::convert_rec(
     // The star gets attached to the declarator.
     std::string new_declarator="*";
 
-    if(q != "" && (!declarator.empty() || subtype.id() == ID_pointer))
+    if(!q.empty() && (!declarator.empty() || subtype.id() == ID_pointer))
     {
       new_declarator+=" "+q;
     }
@@ -442,7 +442,7 @@ std::string expr2ct::convert_rec(
 
     // Providing we have a valid identifer, we can just use that rather than
     // trying to find the concrete type
-    if(typedef_identifer!="")
+    if(!typedef_identifer.empty())
     {
       return q+id2string(typedef_identifer)+d;
     }
@@ -454,7 +454,7 @@ std::string expr2ct::convert_rec(
       {
         std::string dest=q+"struct";
         const irep_idt &tag=to_struct_type(followed).get_tag();
-        if(tag!="")
+        if(!tag.empty())
           dest+=" "+id2string(tag);
         dest+=d;
         return dest;
@@ -463,7 +463,7 @@ std::string expr2ct::convert_rec(
       {
         std::string dest=q+"union";
         const irep_idt &tag=to_union_type(followed).get_tag();
-        if(tag!="")
+        if(!tag.empty())
           dest+=" "+id2string(tag);
         dest+=d;
         return dest;
@@ -479,7 +479,7 @@ std::string expr2ct::convert_rec(
 
     std::string dest=q+"struct";
     const std::string &tag=ns.follow_tag(struct_tag_type).get_string(ID_tag);
-    if(tag!="")
+    if(!tag.empty())
       dest+=" "+tag;
     dest+=d;
 
@@ -492,7 +492,7 @@ std::string expr2ct::convert_rec(
 
     std::string dest=q+"union";
     const std::string &tag=ns.follow_tag(union_tag_type).get_string(ID_tag);
-    if(tag!="")
+    if(!tag.empty())
       dest+=" "+tag;
     dest+=d;
 
@@ -672,7 +672,7 @@ std::string expr2ct::convert_struct_type(
   std::string dest=qualifiers+"struct";
 
   const irep_idt &tag=struct_type.get_tag();
-  if(tag!="")
+  if(!tag.empty())
     dest+=" "+id2string(tag);
 
   if(inc_struct_body && !struct_type.is_incomplete())
@@ -1565,7 +1565,7 @@ std::string expr2ct::convert_member(
 
   irep_idt component_name=src.get_component_name();
 
-  if(component_name!="")
+  if(!component_name.empty())
   {
     const exprt &comp_expr = struct_union_type.get_component(component_name);
 
@@ -1873,7 +1873,7 @@ std::string expr2ct::convert_constant(
   {
     dest=ieee_floatt(to_constant_expr(src)).to_ansi_c_string();
 
-    if(dest!="" && isdigit(dest[dest.size()-1]))
+    if(!dest.empty() && isdigit(dest[dest.size() - 1]))
     {
       if(dest.find('.')==std::string::npos)
         dest+=".0";
@@ -1902,7 +1902,7 @@ std::string expr2ct::convert_constant(
   {
     dest=fixedbvt(to_constant_expr(src)).to_ansi_c_string();
 
-    if(dest!="" && isdigit(dest[dest.size()-1]))
+    if(!dest.empty() && isdigit(dest[dest.size() - 1]))
     {
       if(src.type()==float_type())
         dest+='f';

src/cbmc/bmc.cpp

@@ -139,7 +139,7 @@ safety_checkert::resultt bmct::execute(
         safety_checkert::resultt::ERROR:safety_checkert::resultt::SAFE;
     }
 
-    if(options.get_option("localize-faults")!="")
+    if(!options.get_option("localize-faults").empty())
     {
       fault_localizationt fault_localization(
         goto_functions, *this, options);
@@ -241,8 +241,9 @@ safety_checkert::resultt bmct::stop_on_fail()
     return resultt::UNSAFE;
 
   default:
-    if(options.get_bool_option("dimacs") ||
-       options.get_option("outfile")!="")
+    if(
+      options.get_bool_option("dimacs") ||
+      !options.get_option("outfile").empty())
       return resultt::SAFE;
 
     error() << "decision procedure failed" << eom;

src/cpp/cpp_constructor.cpp

@@ -218,8 +218,7 @@ optionalt<codet> cpp_typecheckt::cpp_constructor(
       }
     }
 
-    // there is always a constructor for non-PODs
-    assert(constructor_name!="");
+    INVARIANT(!constructor_name.empty(), "non-PODs should have a constructor");
 
     side_effect_expr_function_callt function_call(
       cpp_namet(constructor_name, source_location).as_expr(),

src/cpp/cpp_destructor.cpp

@@ -97,8 +97,7 @@ optionalt<codet> cpp_typecheckt::cpp_destructor(
       }
     }
 
-    // there is always a destructor for non-PODs
-    assert(dtor_name!="");
+    INVARIANT(!dtor_name.empty(), "non-PODs should have a destructor");
 
     cpp_namet cpp_name(dtor_name, source_location);
 

src/cpp/cpp_type2name.cpp

@@ -19,8 +19,7 @@ Author: Daniel Kroening, [email protected]
 
 static std::string do_prefix(const std::string &s)
 {
-  if(s.find(',')!=std::string::npos ||
-     (s!="" && isdigit(s[0])))
+  if(s.find(',') != std::string::npos || (!s.empty() && isdigit(s[0])))
     return std::to_string(s.size())+"_"+s;
 
   return s;

src/cpp/cpp_typecheck_expr.cpp

@@ -1205,8 +1205,7 @@ void cpp_typecheckt::typecheck_expr_member(
   }
 
   const irep_idt &component_name=expr.get(ID_component_name);
-
-  assert(component_name!="");
+  INVARIANT(!component_name.empty(), "component name should not be empty");
 
   exprt component;
   component.make_nil();
@@ -2146,7 +2145,7 @@ void cpp_typecheckt::typecheck_side_effect_function_call(
     // special case for the initialization of parents
     if(member.get_bool(ID_C_not_accessible))
     {
-      assert(member.get(ID_C_access)!="");
+      PRECONDITION(!member.get(ID_C_access).empty());
       tmp_object_expr.set(ID_C_not_accessible, true);
       tmp_object_expr.set(ID_C_access, member.get(ID_C_access));
     }