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//
// Copyright 2011,2014 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//
#include <uhd/transport/buffer_pool.hpp>
#include <uhd/transport/zero_copy.hpp>
#include <boost/shared_array.hpp>
#include <vector>
using namespace uhd::transport;
#ifdef UHD_TXRX_DEBUG_PRINTS
/*
* This is the implementation for the static variable 's_buffer_count'
* located in uhd/transport/zero_copy.hpp.
* It is used in the managed_buffer class.
*/
boost::detail::atomic_count managed_buffer::s_buffer_count(0);
#endif // UHD_TXRX_DEBUG_PRINTS
//! pad the byte count to a multiple of alignment
static size_t pad_to_boundary(const size_t bytes, const size_t alignment)
{
return bytes + (alignment - bytes) % alignment;
}
buffer_pool::~buffer_pool(void)
{
/* NOP */
}
/***********************************************************************
* Buffer pool implementation
**********************************************************************/
class buffer_pool_impl : public buffer_pool
{
public:
buffer_pool_impl(const std::vector<ptr_type>& ptrs, boost::shared_array<char> mem)
: _ptrs(ptrs), _mem(mem)
{
/* NOP */
}
ptr_type at(const size_t index) const
{
return _ptrs.at(index);
}
size_t size(void) const
{
return _ptrs.size();
}
private:
std::vector<ptr_type> _ptrs;
boost::shared_array<char> _mem;
};
/***********************************************************************
* Buffer pool factor function
**********************************************************************/
buffer_pool::sptr buffer_pool::make(
const size_t num_buffs, const size_t buff_size, const size_t alignment)
{
// 1) pad the buffer size to be a multiple of alignment
// 2) pad the overall memory size for room after alignment
// 3) allocate the memory in one block of sufficient size
const size_t padded_buff_size = pad_to_boundary(buff_size, alignment);
boost::shared_array<char> mem(new char[padded_buff_size * num_buffs + alignment - 1]);
// Fill a vector with boundary-aligned points in the memory
const size_t mem_start = pad_to_boundary(size_t(mem.get()), alignment);
std::vector<ptr_type> ptrs(num_buffs);
for (size_t i = 0; i < num_buffs; i++) {
ptrs[i] = ptr_type(mem_start + padded_buff_size * i);
}
// Create a new buffer pool implementation with:
// - the pre-computed pointers, and
// - the reference to allocated memory.
return sptr(new buffer_pool_impl(ptrs, mem));
}
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