xref: /aosp_15_r20/frameworks/base/libs/protoutil/src/protobuf.cpp (revision d57664e9bc4670b3ecf6748a746a57c557b6bc9e)

/*
 * Copyright (C) 2016 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.
 */

#include <android/util/protobuf.h>

namespace android {
namespace util {

uint8_t
read_wire_type(uint32_t varint)
{
    return (uint8_t) (varint & WIRE_TYPE_MASK);
}

uint32_t
read_field_id(uint32_t varint)
{
    return varint >> FIELD_ID_SHIFT;
}

size_t
get_varint_size(uint64_t varint)
{
    size_t size = 1;
    while ((varint & ~0x7F)) {
        size++;
        varint >>= 7;
    }
    return size;
}

uint8_t*
write_raw_varint(uint8_t* buf, uint64_t val)
{
    uint8_t* p = buf;
    while (true) {
        if ((val & ~0x7F) == 0) {
            *p++ = (uint8_t)val;
            return p;
        } else {
            *p++ = (uint8_t)((val & 0x7F) | 0x80);
            val >>= 7;
        }
    }
}

uint8_t*
write_length_delimited_tag_header(uint8_t* buf, uint32_t fieldId, size_t size)
{
    buf = write_raw_varint(buf, (fieldId << FIELD_ID_SHIFT) | WIRE_TYPE_LENGTH_DELIMITED);
    buf = write_raw_varint(buf, size);
    return buf;
}

} // util
} // android