2010-11-29 02:33:05 +01:00
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/*
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2015-06-03 07:18:48 +02:00
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Copyright (c) 2010-2015, Arvid Norberg
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2010-11-29 02:33:05 +01:00
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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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
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdlib.h> // free and calloc
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2015-05-18 01:32:13 +02:00
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#include <new> // for bad_alloc
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2010-11-29 02:33:05 +01:00
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#include "libtorrent/packet_buffer.hpp"
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#include "libtorrent/assert.hpp"
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2011-01-30 20:35:20 +01:00
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#include "libtorrent/invariant_check.hpp"
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2010-11-29 02:33:05 +01:00
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namespace libtorrent {
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bool compare_less_wrap(boost::uint32_t lhs, boost::uint32_t rhs
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, boost::uint32_t mask);
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packet_buffer::packet_buffer()
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: m_storage(0)
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, m_capacity(0)
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, m_size(0)
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, m_first(0)
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, m_last(0)
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{}
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2014-01-21 20:26:09 +01:00
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#if TORRENT_USE_INVARIANT_CHECKS
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2011-01-30 20:35:20 +01:00
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void packet_buffer::check_invariant() const
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{
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int count = 0;
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2011-02-21 06:24:41 +01:00
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for (int i = 0; i < int(m_capacity); ++i)
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2011-01-30 20:35:20 +01:00
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{
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count += m_storage[i] ? 1 : 0;
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}
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2011-02-21 06:24:41 +01:00
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TORRENT_ASSERT(count == int(m_size));
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2011-01-30 20:35:20 +01:00
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}
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#endif
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2010-11-29 02:33:05 +01:00
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packet_buffer::~packet_buffer()
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{
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free(m_storage);
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}
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void* packet_buffer::insert(index_type idx, void* value)
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{
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2011-01-30 20:35:20 +01:00
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INVARIANT_CHECK;
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2010-11-29 02:33:05 +01:00
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TORRENT_ASSERT_VAL(idx <= 0xffff, idx);
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// you're not allowed to insert NULLs!
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TORRENT_ASSERT(value);
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2011-01-30 20:35:20 +01:00
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if (value == 0) return remove(idx);
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2010-11-29 02:33:05 +01:00
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if (m_size != 0)
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{
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if (compare_less_wrap(idx, m_first, 0xffff))
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{
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// Index comes before m_first. If we have room, we can simply
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// adjust m_first backward.
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std::size_t free_space = 0;
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for (index_type i = (m_first - 1) & (m_capacity - 1);
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i != (m_first & (m_capacity - 1)); i = (i - 1) & (m_capacity - 1))
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{
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if (m_storage[i & (m_capacity - 1)])
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break;
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++free_space;
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}
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if (((m_first - idx) & 0xffff) > free_space)
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reserve(((m_first - idx) & 0xffff) + m_capacity - free_space);
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m_first = idx;
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}
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else if (idx >= m_first + m_capacity)
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{
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reserve(idx - m_first + 1);
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}
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else if (idx < m_first)
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{
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// We have wrapped.
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2012-11-14 05:53:29 +01:00
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if (idx >= ((m_first + m_capacity) & 0xffff) && m_capacity < 0xffff)
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2010-11-29 02:33:05 +01:00
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{
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2012-11-25 08:03:37 +01:00
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reserve(m_capacity + (idx + 1 - ((m_first + m_capacity) & 0xffff)));
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2010-11-29 02:33:05 +01:00
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}
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}
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if (compare_less_wrap(m_last, (idx + 1) & 0xffff, 0xffff))
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m_last = (idx + 1) & 0xffff;
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}
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else
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{
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m_first = idx;
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m_last = (idx + 1) & 0xffff;
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}
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if (m_capacity == 0) reserve(16);
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void* old_value = m_storage[idx & (m_capacity - 1)];
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m_storage[idx & (m_capacity - 1)] = value;
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2012-03-24 17:08:49 +01:00
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if (m_size == 0) m_first = idx;
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// if we're just replacing an old value, the number
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// of elements in the buffer doesn't actually increase
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if (old_value == 0) ++m_size;
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2010-11-29 02:33:05 +01:00
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TORRENT_ASSERT_VAL(m_first <= 0xffff, m_first);
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return old_value;
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}
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void* packet_buffer::at(index_type idx) const
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{
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2011-01-30 20:35:20 +01:00
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INVARIANT_CHECK;
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2010-11-29 02:33:05 +01:00
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if (idx >= m_first + m_capacity)
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return 0;
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if (compare_less_wrap(idx, m_first, 0xffff))
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{
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return 0;
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}
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2011-01-30 20:35:20 +01:00
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const int mask = (m_capacity - 1);
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return m_storage[idx & mask];
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2010-11-29 02:33:05 +01:00
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}
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void packet_buffer::reserve(std::size_t size)
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{
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2011-01-30 20:35:20 +01:00
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INVARIANT_CHECK;
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2010-11-29 02:33:05 +01:00
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TORRENT_ASSERT_VAL(size <= 0xffff, size);
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std::size_t new_size = m_capacity == 0 ? 16 : m_capacity;
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while (new_size < size)
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new_size <<= 1;
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void** new_storage = (void**)malloc(sizeof(void*) * new_size);
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2015-05-17 17:23:39 +02:00
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#ifndef BOOST_NO_EXCEPTIONS
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if (new_storage == NULL) throw std::bad_alloc();
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#endif
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2010-11-29 02:33:05 +01:00
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for (index_type i = 0; i < new_size; ++i)
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new_storage[i] = 0;
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for (index_type i = m_first; i < (m_first + m_capacity); ++i)
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new_storage[i & (new_size - 1)] = m_storage[i & (m_capacity - 1)];
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free(m_storage);
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m_storage = new_storage;
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m_capacity = new_size;
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}
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void* packet_buffer::remove(index_type idx)
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{
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2011-01-30 20:35:20 +01:00
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INVARIANT_CHECK;
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2010-11-29 02:33:05 +01:00
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// TODO: use compare_less_wrap for this comparison as well
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if (idx >= m_first + m_capacity)
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return 0;
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if (compare_less_wrap(idx, m_first, 0xffff))
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return 0;
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2011-01-30 20:35:20 +01:00
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const int mask = (m_capacity - 1);
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void* old_value = m_storage[idx & mask];
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m_storage[idx & mask] = 0;
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2010-11-29 02:33:05 +01:00
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if (old_value)
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{
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--m_size;
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if (m_size == 0) m_last = m_first;
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}
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if (idx == m_first && m_size != 0)
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{
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2011-02-06 10:34:47 +01:00
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++m_first;
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2011-02-15 11:05:25 +01:00
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for (boost::uint32_t i = 0; i < m_capacity; ++i, ++m_first)
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2011-02-06 10:34:47 +01:00
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if (m_storage[m_first & mask]) break;
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2010-11-29 02:33:05 +01:00
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m_first &= 0xffff;
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}
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if (((idx + 1) & 0xffff) == m_last && m_size != 0)
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{
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2011-02-06 10:34:47 +01:00
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--m_last;
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2011-02-15 11:05:25 +01:00
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for (boost::uint32_t i = 0; i < m_capacity; ++i, --m_last)
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2011-02-06 10:34:47 +01:00
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if (m_storage[m_last & mask]) break;
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2010-11-29 02:33:05 +01:00
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++m_last;
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m_last &= 0xffff;
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}
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TORRENT_ASSERT_VAL(m_first <= 0xffff, m_first);
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return old_value;
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}
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}
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