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//
// Copyright 2011-2011 Ettus Research LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
#include <uhd/transport/buffer_pool.hpp>
#include <boost/shared_array.hpp>
#include <vector>
using namespace uhd::transport;
//! 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 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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