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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "mapped_file_input.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/mman.h>
namespace vespalib {
MappedFileInput::MappedFileInput(const vespalib::string &file_name)
: _fd(open(file_name.c_str(), O_RDONLY)),
_data((char *)MAP_FAILED),
_size(0),
_used(0)
{
struct stat info;
if ((_fd != -1) && fstat(_fd, &info) == 0) {
_data = static_cast<char*>(mmap(0, info.st_size, PROT_READ, MAP_SHARED, _fd, 0));
if (_data != MAP_FAILED) {
_size = info.st_size;
madvise(_data, _size, MADV_SEQUENTIAL);
#ifdef __linux__
madvise(_data, _size, MADV_DONTDUMP);
#endif
}
}
}
MappedFileInput::~MappedFileInput()
{
if (valid()) {
munmap(_data, _size);
}
if (_fd != -1) {
close(_fd);
}
}
bool MappedFileInput::valid() const
{
return (_data != MAP_FAILED);
}
Memory
MappedFileInput::obtain()
{
return Memory((_data + _used), (_size - _used));
}
Input &
MappedFileInput::evict(size_t bytes)
{
_used += bytes;
return *this;
}
} // namespace vespalib
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