95 lines
2.6 KiB
C++
95 lines
2.6 KiB
C++
/*
|
|
* 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 <cinttypes>
|
|
#include <cstring>
|
|
|
|
#include "android-base/logging.h"
|
|
|
|
#include "wifilogd/message_buffer.h"
|
|
|
|
namespace android {
|
|
namespace wifilogd {
|
|
|
|
using local_utils::CopyFromBufferOrDie;
|
|
|
|
MessageBuffer::MessageBuffer(size_t size)
|
|
: data_(new uint8_t[size]), capacity_(size), read_pos_(0), write_pos_(0) {
|
|
CHECK(size > GetHeaderSize());
|
|
}
|
|
|
|
bool MessageBuffer::Append(const uint8_t* message, uint16_t message_len) {
|
|
CHECK(message_len);
|
|
|
|
if (!CanFitNow(message_len)) {
|
|
return false;
|
|
}
|
|
|
|
AppendHeader(message_len);
|
|
AppendRawBytes(message, message_len);
|
|
return true;
|
|
}
|
|
|
|
bool MessageBuffer::CanFitEver(uint16_t length) const {
|
|
// This unusual formulation is intended to avoid overflow.
|
|
return capacity_ - GetHeaderSize() >= length;
|
|
}
|
|
|
|
bool MessageBuffer::CanFitNow(uint16_t length) const {
|
|
// This unusual formulation is intended to avoid overflow/underflow.
|
|
return GetFreeSize() >= GetHeaderSize() &&
|
|
GetFreeSize() - GetHeaderSize() >= length;
|
|
}
|
|
|
|
void MessageBuffer::Clear() {
|
|
read_pos_ = 0;
|
|
write_pos_ = 0;
|
|
}
|
|
|
|
std::tuple<const uint8_t*, size_t> MessageBuffer::ConsumeNextMessage() {
|
|
if (read_pos_ == write_pos_) {
|
|
return {nullptr, 0};
|
|
}
|
|
|
|
const auto& header = CopyFromBufferOrDie<LengthHeader>(
|
|
data_.get() + read_pos_, GetReadableSize());
|
|
read_pos_ += sizeof(header);
|
|
|
|
const uint8_t* payload_start = data_.get() + read_pos_;
|
|
read_pos_ += header.payload_len;
|
|
CHECK(read_pos_ <= write_pos_);
|
|
|
|
return {payload_start, header.payload_len};
|
|
}
|
|
|
|
void MessageBuffer::Rewind() { read_pos_ = 0; }
|
|
|
|
// Private methods below.
|
|
|
|
void MessageBuffer::AppendHeader(uint16_t message_len) {
|
|
LengthHeader header;
|
|
header.payload_len = message_len;
|
|
AppendRawBytes(&header, sizeof(header));
|
|
}
|
|
|
|
void MessageBuffer::AppendRawBytes(const void* data_start, size_t data_len) {
|
|
std::memcpy(data_.get() + write_pos_, data_start, data_len);
|
|
write_pos_ += data_len;
|
|
CHECK(write_pos_ <= capacity_);
|
|
}
|
|
|
|
} // namespace wifilogd
|
|
} // namespace android
|