0564da5fdc
NULL is valid when size is 0, but memcpy uses nonnull attributes, so let's not poke the bear
99 lines
3.7 KiB
C++
99 lines
3.7 KiB
C++
// Copyright (c) 2018, The Monero Project
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification, are
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// permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this list of
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// conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
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// of conditions and the following disclaimer in the documentation and/or other
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// materials provided with the distribution.
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//
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// 3. Neither the name of the copyright holder nor the names of its contributors may be
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// used to endorse or promote products derived from this software without specific
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// prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include <string.h>
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#include "net/buffer.h"
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#undef MONERO_DEFAULT_LOG_CATEGORY
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#define MONERO_DEFAULT_LOG_CATEGORY "net.buffer"
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namespace epee
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{
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namespace net_utils
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{
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void buffer::append(const void *data, size_t sz)
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{
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const size_t capacity = storage.capacity();
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const size_t avail = capacity - storage.size();
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CHECK_AND_ASSERT_THROW_MES(storage.size() < std::numeric_limits<size_t>::max() - sz, "Too much data to append");
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// decide when to move
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if (sz > avail)
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{
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// we have to reallocate or move
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const bool move = size() + sz <= capacity;
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if (move)
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{
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const size_t bytes = storage.size() - offset;
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NET_BUFFER_LOG("appending " << sz << " from " << size() << " by moving " << bytes << " from offset " << offset << " first (forced)");
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memmove(storage.data(), storage.data() + offset, bytes);
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storage.resize(bytes);
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offset = 0;
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}
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else
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{
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NET_BUFFER_LOG("appending " << sz << " from " << size() << " by reallocating");
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std::vector<uint8_t> new_storage;
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size_t reserve = (((size() + sz) * 3 / 2) + 4095) & ~4095;
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new_storage.reserve(reserve);
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new_storage.resize(size());
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if (size() > 0)
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memcpy(new_storage.data(), storage.data() + offset, storage.size() - offset);
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offset = 0;
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std::swap(storage, new_storage);
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}
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}
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else
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{
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// we have space already
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if (size() <= 4096 && offset > 4096 * 16 && offset >= capacity / 2)
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{
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// we have little to move, and we're far enough into the buffer that it's probably a win to move anyway
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const size_t pos = storage.size() - offset;
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NET_BUFFER_LOG("appending " << sz << " from " << size() << " by moving " << pos << " from offset " << offset << " first (unforced)");
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memmove(storage.data(), storage.data() + offset, storage.size() - offset);
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storage.resize(pos);
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offset = 0;
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}
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else
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{
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NET_BUFFER_LOG("appending " << sz << " from " << size() << " by writing to existing capacity");
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}
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}
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// add the new data
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storage.insert(storage.end(), (const uint8_t*)data, (const uint8_t*)data + sz);
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NET_BUFFER_LOG("storage now " << offset << "/" << storage.size() << "/" << storage.capacity());
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}
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}
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}
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