chromium/third_party/perfetto/include/perfetto/protozero/packed_repeated_fields.h

/*
 * Copyright (C) 2019 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef INCLUDE_PERFETTO_PROTOZERO_PACKED_REPEATED_FIELDS_H_
#define INCLUDE_PERFETTO_PROTOZERO_PACKED_REPEATED_FIELDS_H_

#include <stdint.h>

#include <array>
#include <memory>
#include <type_traits>

#include "perfetto/base/logging.h"
#include "perfetto/protozero/proto_utils.h"

namespace protozero {

// This file contains classes used when encoding packed repeated fields.
// To encode such a field, the caller is first expected to accumulate all of the
// values in one of the following types (depending on the wire type of the
// individual elements), defined below:
// * protozero::PackedVarInt
// * protozero::PackedFixedSizeInt</*element_type=*/ uint32_t>
// Then that buffer is passed to the protozero-generated setters as an argument.
// After calling the setter, the buffer can be destroyed.
//
// An example of encoding a packed field:
//   protozero::HeapBuffered<protozero::Message> msg;
//   protozero::PackedVarInt buf;
//   buf.Append(42);
//   buf.Append(-1);
//   msg->set_fieldname(buf);
//   msg.SerializeAsString();

class PackedBufferBase { … };

class PackedVarInt : public PackedBufferBase { … };

template <typename T /* e.g. uint32_t for Fixed32 */>
class PackedFixedSizeInt : public PackedBufferBase { … };

}  // namespace protozero

#endif  // INCLUDE_PERFETTO_PROTOZERO_PACKED_REPEATED_FIELDS_H_