diff options
Diffstat (limited to 'src/google/protobuf/compiler/java/java_helpers.cc')
-rw-r--r-- | src/google/protobuf/compiler/java/java_helpers.cc | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/google/protobuf/compiler/java/java_helpers.cc b/src/google/protobuf/compiler/java/java_helpers.cc index dbb86b87..957076cb 100644 --- a/src/google/protobuf/compiler/java/java_helpers.cc +++ b/src/google/protobuf/compiler/java/java_helpers.cc @@ -75,6 +75,8 @@ const char* kForbiddenWordList[] = { "class", }; +const int kDefaultLookUpStartFieldNumber = 40; + bool IsForbidden(const string& field_name) { for (int i = 0; i < GOOGLE_ARRAYSIZE(kForbiddenWordList); ++i) { if (field_name == kForbiddenWordList[i]) { @@ -103,6 +105,20 @@ string FieldName(const FieldDescriptor* field) { } +// Judge whether should use table or use look up. +// Copied from com.google.protobuf.SchemaUtil.shouldUseTableSwitch +bool ShouldUseTable(int lo, int hi, int number_of_fields) { + if (hi < kDefaultLookUpStartFieldNumber) { + return true; + } + int64 table_space_cost = (static_cast<int64>(hi) - lo + 1); // words + int64 table_time_cost = 3; // comparisons + int64 lookup_space_cost = 3 + 2 * static_cast<int64>(number_of_fields); + int64 lookup_time_cost = 3 + number_of_fields; + return table_space_cost + 3 * table_time_cost <= + lookup_space_cost + 3 * lookup_time_cost; +} + } // namespace void PrintGeneratedAnnotation(io::Printer* printer, char delimiter, @@ -915,6 +931,23 @@ void EscapeUtf16ToString(uint16 code, string* output) { output->append(StringPrintf("\\u%04x", code)); } } + +std::pair<int, int> GetTableDrivenNumberOfEntriesAndLookUpStartFieldNumber( + const FieldDescriptor** fields, int count) { + GOOGLE_CHECK_GT(count, 0); + int table_driven_number_of_entries = count; + int look_up_start_field_number = 0; + for (int i = 0; i < count; i++) { + const int field_number = fields[i]->number(); + if (ShouldUseTable(fields[0]->number(), field_number, i + 1)) { + table_driven_number_of_entries = + field_number - fields[0]->number() + 1 + count - i - 1; + look_up_start_field_number = field_number + 1; + } + } + return std::make_pair( + table_driven_number_of_entries, look_up_start_field_number); +} } // namespace java } // namespace compiler } // namespace protobuf |