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// Copyright (C) by Josh Blum. See LICENSE.txt for licensing information.
#include <gras/buffer_queue.hpp>
#include <gras_impl/debug.hpp>
#include <boost/circular_buffer.hpp>
using namespace gras;
struct BufferQueuePool : BufferQueue
{
BufferQueuePool(const SBufferConfig &config, const size_t num):
_token(config.token), //save config, its holds token
_queue(boost::circular_buffer<SBuffer>(num))
{
//NOP
}
~BufferQueuePool(void)
{
_token.reset();
_queue.clear();
}
SBuffer &front(void)
{
ASSERT(not _queue.empty());
ASSERT(_queue.front());
return _queue.front();
}
void pop(void)
{
ASSERT(not _queue.empty());
SBuffer &buff = _queue.front();
//This little half consumed metric lets us keep using
//the same buffer if its only been partially consumed.
//Input buffer stitching will rejoin contiguous memory.
if (buff.offset > buff.get_actual_length()/2)
{
buff.reset(); //dont hold ref
_queue.pop_front();
}
else
{
//enables buffer stitching on pool buffers
buff.last = buff.get();
}
}
void push(const SBuffer &buff)
{
//is it my buffer? otherwise dont keep it
if GRAS_UNLIKELY(buff->config.token.lock() != _token) return;
//should never get a buffer from a circ queue
ASSERT(buff.get_user_index() == size_t(~0));
_queue.push_back(buff);
}
bool empty(void) const
{
return _queue.empty();
}
SBufferToken _token;
boost::circular_buffer<SBuffer> _queue;
};
BufferQueueSptr BufferQueue::make_pool(
const SBufferConfig &config,
const size_t num_buffs
){
BufferQueueSptr queue(new BufferQueuePool(config, num_buffs));
for (size_t i = 0; i < num_buffs; i++)
{
SBuffer buff(config);
std::memset(buff.get_actual_memory(), 0, buff.get_actual_length());
//buffer derefs and returns to this queue thru token callback
}
return queue;
}
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