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tdfec/td/fec/raptorq/Decoder.h

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+/*
+    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
+*/
+#pragma once
+#include "td/fec/raptorq/Solver.h"
+#include "td/fec/raptorq/Encoder.h"
+
+#include <set>
+
+namespace td {
+namespace raptorq {
+
+class Decoder {
+ public:
+  static Result<std::unique_ptr<Decoder>> create(Encoder::Parameters p);
+  Decoder(const Rfc::Parameters &p, size_t symbol_size, size_t data_size);
+
+  Status add_symbol(SymbolRef symbol);
+
+  struct DataWithEncoder {
+    BufferSlice data;
+    std::unique_ptr<Encoder> encoder;
+  };
+  Result<DataWithEncoder> try_decode(bool need_encoder);
+  bool may_try_decode() const;
+
+ private:
+  Rfc::Parameters p_;
+  size_t symbol_size_;
+
+  bool may_decode_{false};
+  vector<bool> mask_;
+  size_t mask_size_{0};
+  BufferSlice data_;
+  size_t data_size_;
+
+  bool flush_symbols_{false};
+  bool slow_path_{false};
+  size_t slow_symbols_;
+  BufferSlice buffer_;
+  std::vector<SymbolRef> symbols_;
+  std::set<uint32> slow_symbols_set_;
+  std::string zero_symbol_;
+
+  void add_small_symbol(SymbolRef symbol);
+  void add_big_symbol(SymbolRef symbol);
+
+  void update_may_decode();
+
+  void on_first_slow_path();
+
+  void flush_symbols();
+};
+
+}  // namespace raptorq
+}  // namespace td