Files
scylladb/core/fstream.cc
Avi Kivity af0bf06836 core: add file_data_source, file_input_stream
Implement a character stream backed by a file.
2015-02-11 15:38:51 +02:00

28 lines
744 B
C++

/*
* Copyright (C) 2015 Cloudius Systems, Ltd.
*/
#include "fstream.hh"
#include <new>
#include <malloc.h>
#include <algorithm>
future<temporary_buffer<char>>
file_data_source_impl::get() {
// must align allocation for dma
auto p = ::memalign(std::min<size_t>(_buffer_size, 4096), _buffer_size);
if (!p) {
throw std::bad_alloc();
}
auto q = static_cast<char*>(p);
temporary_buffer<char> buf(q, _buffer_size, make_free_deleter(p));
auto old_pos = _pos;
_pos += _buffer_size;
return _file.dma_read(old_pos, q, _buffer_size).then(
[buf = std::move(buf)] (size_t size) mutable {
buf.trim(size);
return make_ready_future<temporary_buffer<char>>(std::move(buf));
});
}