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ton/tdfec/td/fec/online/Decoder.cpp
2019-09-07 14:33:36 +04:00

78 lines
2.8 KiB
C++

/*
This file is part of TON Blockchain Library.
TON Blockchain Library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.
TON Blockchain Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with TON Blockchain Library. If not, see <http://www.gnu.org/licenses/>.
Copyright 2017-2019 Telegram Systems LLP
*/
#include "td/fec/online/Decoder.h"
namespace td {
namespace online_code {
Result<std::unique_ptr<Decoder>> Decoder::create(Encoder::Parameters p) {
return std::make_unique<Decoder>(p.symbol_size, p.data_size);
}
Decoder::Decoder(size_t symbol_size, size_t data_size)
: parameters_(Rfc::get_parameters((data_size + symbol_size - 1) / symbol_size).move_as_ok())
, symbol_size_(symbol_size)
, data_size_(data_size) {
MatrixGF256 d_{1, symbol_size_};
d_.set_zero();
std::vector<uint32> e_cnt(parameters_.outer_encoding_blocks_count(), 0);
std::vector<std::vector<uint32>> e(parameters_.outer_encoding_blocks_count());
parameters_.outer_encoding_for_each([&](uint32 i, uint32 j) { e_cnt[i]++; });
for (uint32 i = 0; i < parameters_.outer_encoding_blocks_count(); i++) {
e[i].reserve(e_cnt[i]);
}
parameters_.outer_encoding_for_each([&](uint32 i, uint32 j) { e[i].push_back(j); });
for (uint32 i = 0; i < parameters_.outer_encoding_blocks_count(); i++) {
decoding_.add_equation(e[i], d_.row(0));
}
}
Status Decoder::add_symbol(raptorq::SymbolRef symbol_ref) {
if (symbol_ref.data.size() != symbol_size_) {
return Status::Error("Symbol has invalid length");
}
auto offset = decoding_.ready_symbols().size();
decoding_.add_equation(parameters_.get_inner_encoding_row(symbol_ref.id), symbol_ref.data);
//LOG(ERROR) << inner_decoding_.ready_symbols().size();
for (auto symbol_id : decoding_.ready_symbols().substr(offset)) {
if (symbol_id < parameters_.source_blocks_count()) {
ready_cnt_++;
}
}
return Status::OK();
}
bool Decoder::is_ready() const {
return ready_cnt_ == parameters_.source_blocks_count();
}
BufferSlice Decoder::get_data() const {
CHECK(is_ready());
BufferSlice res(data_size_);
for (uint32 i = 0; i < parameters_.source_blocks_count(); i++) {
auto dest = res.as_slice().substr(i * symbol_size_);
dest.copy_from(decoding_.get_symbol(i).truncate(dest.size()));
}
return res;
}
} // namespace online_code
} // namespace td