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64 lines
1.9 KiB
C++
64 lines
1.9 KiB
C++
/*
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This file is part of TON Blockchain Library.
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TON Blockchain Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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TON Blockchain Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with TON Blockchain Library. If not, see <http://www.gnu.org/licenses/>.
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Copyright 2017-2019 Telegram Systems LLP
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*/
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#include "td/utils/find_boundary.h"
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#include <cstring>
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namespace td {
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bool find_boundary(ChainBufferReader range, Slice boundary, size_t &already_read) {
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range.advance(already_read);
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const int MAX_BOUNDARY_LENGTH = 70;
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CHECK(boundary.size() <= MAX_BOUNDARY_LENGTH + 4);
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while (!range.empty()) {
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Slice ready = range.prepare_read();
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if (ready[0] == boundary[0]) {
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if (range.size() < boundary.size()) {
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return false;
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}
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auto save_range = range.clone();
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char x[MAX_BOUNDARY_LENGTH + 4];
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range.advance(boundary.size(), {x, sizeof(x)});
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if (Slice(x, boundary.size()) == boundary) {
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return true;
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}
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// not a boundary, restoring previous state and skip one symbol
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range = std::move(save_range);
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range.advance(1);
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already_read++;
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} else {
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const char *ptr = static_cast<const char *>(std::memchr(ready.data(), boundary[0], ready.size()));
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size_t shift;
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if (ptr == nullptr) {
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shift = ready.size();
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} else {
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shift = ptr - ready.data();
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}
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already_read += shift;
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range.advance(shift);
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}
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}
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return false;
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}
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} // namespace td
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