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// Copyright (c) 2018-2022, The Monero Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <limits>
#include <string.h>
#include "net/buffer.h"
#undef MONERO_DEFAULT_LOG_CATEGORY
#define MONERO_DEFAULT_LOG_CATEGORY "net.buffer"
namespace epee
{
namespace net_utils
{
void buffer::append(const void *data, size_t sz)
{
const size_t capacity = storage.capacity();
const size_t avail = capacity - storage.size();
CHECK_AND_ASSERT_THROW_MES(storage.size() < std::numeric_limits<size_t>::max() - sz, "Too much data to append");
// decide when to move
if (sz > avail)
{
// we have to reallocate or move
const bool move = size() + sz <= capacity;
if (move)
{
const size_t bytes = storage.size() - offset;
NET_BUFFER_LOG("appending " << sz << " from " << size() << " by moving " << bytes << " from offset " << offset << " first (forced)");
memmove(storage.data(), storage.data() + offset, bytes);
storage.resize(bytes);
offset = 0;
}
else
{
NET_BUFFER_LOG("appending " << sz << " from " << size() << " by reallocating");
std::vector<uint8_t> new_storage;
size_t reserve = (((size() + sz) * 3 / 2) + 4095) & ~4095;
new_storage.reserve(reserve);
new_storage.resize(size());
if (size() > 0)
memcpy(new_storage.data(), storage.data() + offset, storage.size() - offset);
offset = 0;
std::swap(storage, new_storage);
}
}
else
{
// we have space already
if (size() <= 4096 && offset > 4096 * 16 && offset >= capacity / 2)
{
// we have little to move, and we're far enough into the buffer that it's probably a win to move anyway
const size_t pos = storage.size() - offset;
NET_BUFFER_LOG("appending " << sz << " from " << size() << " by moving " << pos << " from offset " << offset << " first (unforced)");
memmove(storage.data(), storage.data() + offset, storage.size() - offset);
storage.resize(pos);
offset = 0;
}
else
{
NET_BUFFER_LOG("appending " << sz << " from " << size() << " by writing to existing capacity");
}
}
// add the new data
storage.insert(storage.end(), (const uint8_t*)data, (const uint8_t*)data + sz);
NET_BUFFER_LOG("storage now " << offset << "/" << storage.size() << "/" << storage.capacity());
}
}
}
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