use switch statements for BASE_TYPE_ lookups (google#7813)

jochenparm · Oct 29, 2024 · 8ba1683 · 8ba1683
1 parent 2239bd4
commit 8ba1683
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Showing 5 changed files with 56 additions and 49 deletions.
diff --git a/include/flatbuffers/idl.h b/include/flatbuffers/idl.h
@@ -146,12 +146,29 @@ inline bool IsUnsigned(BaseType t) {
          (t == BASE_TYPE_ULONG);
 }
 
-// clang-format on
+inline size_t SizeOf(const BaseType t) {
+  switch (t) {
+  #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
+    case BASE_TYPE_##ENUM: return sizeof(CTYPE);
+      FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+  #undef FLATBUFFERS_TD
+    default: FLATBUFFERS_ASSERT(0);
+  }
+  return 0;
+}
 
-extern const char *const kTypeNames[];
-extern const char kTypeSizes[];
+inline const char* TypeName(const BaseType t) {
+  switch (t) {
+  #define FLATBUFFERS_TD(ENUM, IDLTYPE, ...) \
+    case BASE_TYPE_##ENUM: return IDLTYPE;
+      FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+  #undef FLATBUFFERS_TD
+    default: FLATBUFFERS_ASSERT(0);
+  }
+  return nullptr;
+}
 
-inline size_t SizeOf(BaseType t) { return kTypeSizes[t]; }
+// clang-format on
 
 struct StructDef;
 struct EnumDef;

diff --git a/src/idl_gen_cpp.cpp b/src/idl_gen_cpp.cpp
@@ -721,19 +721,20 @@ class CppGenerator : public BaseGenerator {
 
   // Return a C++ type from the table in idl.h
   std::string GenTypeBasic(const Type &type, bool user_facing_type) const {
-    // clang-format off
-    static const char *const ctypename[] = {
-      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
-        #CTYPE,
-        FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
-      #undef FLATBUFFERS_TD
-    };
-    // clang-format on
     if (user_facing_type) {
       if (type.enum_def) return WrapInNameSpace(*type.enum_def);
       if (type.base_type == BASE_TYPE_BOOL) return "bool";
     }
-    return ctypename[type.base_type];
+    switch (type.base_type) {
+    // clang-format off
+    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
+      case BASE_TYPE_##ENUM: return #CTYPE;
+          FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+    #undef FLATBUFFERS_TD
+    //clang-format on
+      default: FLATBUFFERS_ASSERT(0);
+    }
+    return "";
   }
 
   // Return a C++ pointer type, specialized to the actual struct/table types,
@@ -2262,11 +2263,14 @@ class CppGenerator : public BaseGenerator {
       const bool is_array = IsArray(curr_field->value.type);
       const bool is_struct = IsStruct(curr_field->value.type);
 
-      // If encouter a key field, call KeyCompareWithValue to compare this field.
+      // If encouter a key field, call KeyCompareWithValue to compare this
+      // field.
       if (curr_field->key) {
-        code_ +=
-          space + "const auto {{RHS}} = {{RHS_PREFIX}}.{{CURR_FIELD_NAME}}();";
-        code_ += space + "const auto {{CURR_FIELD_NAME}}_compare_result = {{LHS_PREFIX}}.KeyCompareWithValue({{RHS}});";
+        code_ += space +
+                 "const auto {{RHS}} = {{RHS_PREFIX}}.{{CURR_FIELD_NAME}}();";
+        code_ += space +
+                 "const auto {{CURR_FIELD_NAME}}_compare_result = "
+                 "{{LHS_PREFIX}}.KeyCompareWithValue({{RHS}});";
 
         code_ += space + "if ({{CURR_FIELD_NAME}}_compare_result != 0)";
         code_ += space + "  return {{CURR_FIELD_NAME}}_compare_result;";
@@ -2298,7 +2302,9 @@ class CppGenerator : public BaseGenerator {
 
         } else if (IsStruct(elem_type)) {
           if (curr_field->key) {
-            code_ += space + "const auto {{CURR_FIELD_NAME}}_compare_result = {{LHS_PREFIX}}.KeyCompareWithValue({{RHS}});";
+            code_ += space +
+                     "const auto {{CURR_FIELD_NAME}}_compare_result = "
+                     "{{LHS_PREFIX}}.KeyCompareWithValue({{RHS}});";
             code_ += space + "if ({{CURR_FIELD_NAME}}_compare_result != 0)";
             code_ += space + "  return {{CURR_FIELD_NAME}}_compare_result;";
             continue;
@@ -2331,7 +2337,7 @@ class CppGenerator : public BaseGenerator {
       code_ += "    return *{{FIELD_NAME}}() < *o->{{FIELD_NAME}}();";
     } else if (is_array || is_struct) {
       code_ += "    return KeyCompareWithValue(o->{{FIELD_NAME}}()) < 0;";
-    }else {
+    } else {
       code_ += "    return {{FIELD_NAME}}() < o->{{FIELD_NAME}}();";
     }
     code_ += "  }";
@@ -2343,8 +2349,8 @@ class CppGenerator : public BaseGenerator {
     } else if (is_array) {
       const auto &elem_type = field.value.type.VectorType();
       std::string input_type = "::flatbuffers::Array<" +
-                               GenTypeGet(elem_type, "", "", "", false) +
-                               ", " + NumToString(elem_type.fixed_length) + ">";
+                               GenTypeGet(elem_type, "", "", "", false) + ", " +
+                               NumToString(elem_type.fixed_length) + ">";
       code_.SetValue("INPUT_TYPE", input_type);
       code_ +=
           "  int KeyCompareWithValue(const {{INPUT_TYPE}} *_{{FIELD_NAME}}"
@@ -2367,7 +2373,8 @@ class CppGenerator : public BaseGenerator {
             "      const auto &lhs_{{FIELD_NAME}} = "
             "*(curr_{{FIELD_NAME}}->Get(i));";
         code_ +=
-            "      const auto &rhs_{{FIELD_NAME}} = *(_{{FIELD_NAME}}->Get(i));";
+            "      const auto &rhs_{{FIELD_NAME}} = "
+            "*(_{{FIELD_NAME}}->Get(i));";
         GenComparatorForStruct(*elem_type.struct_def, 6,
                                "lhs_" + code_.GetValue("FIELD_NAME"),
                                "rhs_" + code_.GetValue("FIELD_NAME"));
@@ -3980,8 +3987,8 @@ class CppCodeGenerator : public CodeGenerator {
   // Generate code from the provided `buffer` of given `length`. The buffer is a
   // serialized reflection.fbs.
   Status GenerateCode(const uint8_t *buffer, int64_t length) override {
-    (void) buffer;
-    (void) length;
+    (void)buffer;
+    (void)length;
     return Status::NOT_IMPLEMENTED;
   }
 

diff --git a/src/idl_gen_fbs.cpp b/src/idl_gen_fbs.cpp
@@ -37,7 +37,7 @@ static std::string GenType(const Type &type, bool underlying = false) {
         return type.enum_def->defined_namespace->GetFullyQualifiedName(
             type.enum_def->name);
       } else {
-        return kTypeNames[type.base_type];
+        return TypeName(type.base_type);
       }
   }
 }

diff --git a/src/idl_parser.cpp b/src/idl_parser.cpp
@@ -356,23 +356,6 @@ template<typename T> static void AssignIndices(const std::vector<T *> &defvec) {
 
 }  // namespace
 
-// clang-format off
-const char *const kTypeNames[] = {
-  #define FLATBUFFERS_TD(ENUM, IDLTYPE, ...) \
-    IDLTYPE,
-    FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
-  #undef FLATBUFFERS_TD
-  nullptr
-};
-
-const char kTypeSizes[] = {
-  #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
-    sizeof(CTYPE),
-    FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
-  #undef FLATBUFFERS_TD
-};
-// clang-format on
-
 void Parser::Message(const std::string &msg) {
   if (!error_.empty()) error_ += "\n";  // log all warnings and errors
   error_ += file_being_parsed_.length() ? AbsolutePath(file_being_parsed_) : "";
@@ -1947,8 +1930,8 @@ CheckedError Parser::ParseFunction(const std::string *name, Value &e) {
   const auto functionname = attribute_;
   if (!IsFloat(e.type.base_type)) {
     return Error(functionname + ": type of argument mismatch, expecting: " +
-                 kTypeNames[BASE_TYPE_DOUBLE] +
-                 ", found: " + kTypeNames[e.type.base_type] +
+                 TypeName(BASE_TYPE_DOUBLE) +
+                 ", found: " + TypeName(e.type.base_type) +
                  ", name: " + (name ? *name : "") + ", value: " + e.constant);
   }
   NEXT();
@@ -1994,8 +1977,8 @@ CheckedError Parser::TryTypedValue(const std::string *name, int dtoken,
       e.type.base_type = req;
     } else {
       return Error(std::string("type mismatch: expecting: ") +
-                   kTypeNames[e.type.base_type] +
-                   ", found: " + kTypeNames[req] +
+                   TypeName(e.type.base_type) +
+                   ", found: " + TypeName(req) +
                    ", name: " + (name ? *name : "") + ", value: " + e.constant);
     }
   }
@@ -2056,7 +2039,7 @@ CheckedError Parser::ParseSingleValue(const std::string *name, Value &e,
       return Error(
           std::string("type mismatch or invalid value, an initializer of "
                       "non-string field must be trivial ASCII string: type: ") +
-          kTypeNames[in_type] + ", name: " + (name ? *name : "") +
+          TypeName(in_type) + ", name: " + (name ? *name : "") +
           ", value: " + attribute_);
     }
 
@@ -2128,7 +2111,7 @@ CheckedError Parser::ParseSingleValue(const std::string *name, Value &e,
   if (!match) {
     std::string msg;
     msg += "Cannot assign token starting with '" + TokenToStringId(token_) +
-           "' to value of <" + std::string(kTypeNames[in_type]) + "> type.";
+           "' to value of <" + std::string(TypeName(in_type)) + "> type.";
     return Error(msg);
   }
   const auto match_type = e.type.base_type;  // may differ from in_type

diff --git a/tests/fuzz_test.cpp b/tests/fuzz_test.cpp
@@ -234,7 +234,7 @@ void FuzzTest2() {
           break;
         default:
           // All the scalar types.
-          schema += flatbuffers::kTypeNames[base_type];
+          schema += flatbuffers::TypeName(base_type);
 
           if (!deprecated) {
             // We want each instance to use its own random value.