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tdfec/td/fec/common/SymbolsView.cpp

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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
+*/
+#include "td/fec/common/SymbolsView.h"
+namespace td {
+namespace raptorq {
+SymbolsView::SymbolsView(size_t symbols_count, size_t symbol_size, Slice data) {
+  symbols_.reserve(symbols_count);
+  zero_symbol_ = std::string(symbol_size, '\0');
+  last_symbol_ = std::string(symbol_size, '\0');
+
+  for (uint32 symbol_i = 0; symbol_i < symbols_count; symbol_i++) {
+    auto offset = symbol_i * symbol_size;
+    Slice symbol;
+    if (offset < data.size()) {
+      symbol = data.substr(offset).truncate(symbol_size);
+    }
+    Slice slice;
+    if (symbol.empty()) {
+      slice = zero_symbol_;
+    } else if (symbol.size() < symbol_size) {
+      MutableSlice(last_symbol_).copy_from(symbol);
+      slice = last_symbol_;
+    } else {
+      slice = symbol;
+    }
+    symbols_.push_back(SymbolRef{symbol_i, slice});
+  }
+}
+}  // namespace raptorq
+}  // namespace td