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/***************************************************************************
* lib/io/mem_file.cpp
*
* Part of the STXXL. See http://stxxl.sourceforge.net
*
* Copyright (C) 2008 Andreas Beckmann <beckmann@cs.uni-frankfurt.de>
* Copyright (C) 2013-2014 Timo Bingmann <tb@panthema.net>
*
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
**************************************************************************/
#include <cstring>
#include <limits>
#include <cassert>
#include <stxxl/bits/io/mem_file.h>
#include <stxxl/bits/io/iostats.h>
STXXL_BEGIN_NAMESPACE
void mem_file::serve(void* buffer, offset_type offset, size_type bytes,
request::request_type type)
{
scoped_mutex_lock lock(m_mutex);
if (type == request::READ)
{
stats::scoped_read_timer read_timer(bytes);
memcpy(buffer, m_ptr + offset, bytes);
}
else
{
stats::scoped_write_timer write_timer(bytes);
memcpy(m_ptr + offset, buffer, bytes);
}
}
const char* mem_file::io_type() const
{
return "memory";
}
mem_file::~mem_file()
{
free(m_ptr);
m_ptr = NULL;
}
void mem_file::lock()
{
// nothing to do
}
file::offset_type mem_file::size()
{
return m_size;
}
void mem_file::set_size(offset_type newsize)
{
scoped_mutex_lock lock(m_mutex);
assert(newsize <= std::numeric_limits<offset_type>::max());
m_ptr = (char*)realloc(m_ptr, (size_t)newsize);
m_size = newsize;
}
void mem_file::discard(offset_type offset, offset_type size)
{
scoped_mutex_lock lock(m_mutex);
#ifndef STXXL_MEMFILE_DONT_CLEAR_FREED_MEMORY
// overwrite the freed region with uninitialized memory
STXXL_VERBOSE("discard at " << offset << " len " << size);
void* uninitialized = malloc(STXXL_BLOCK_ALIGN);
while (size >= STXXL_BLOCK_ALIGN) {
memcpy(m_ptr + offset, uninitialized, STXXL_BLOCK_ALIGN);
offset += STXXL_BLOCK_ALIGN;
size -= STXXL_BLOCK_ALIGN;
}
assert(size <= std::numeric_limits<offset_type>::max());
if (size > 0)
memcpy(m_ptr + offset, uninitialized, (size_t)size);
free(uninitialized);
#else
STXXL_UNUSED(offset);
STXXL_UNUSED(size);
#endif
}
STXXL_END_NAMESPACE
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