/usr/include/jellyfish/mapped_file.hpp is in libjellyfish-2.0-dev 2.2.6-1+b1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 | /* This file is part of Jellyfish.
Jellyfish 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.
Jellyfish 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 Jellyfish. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __JELLYFISH_MAPPED_FILE_HPP__
#define __JELLYFISH_MAPPED_FILE_HPP__
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <vector>
#include <errno.h>
#include <iostream>
#include <jellyfish/err.hpp>
namespace jellyfish {
class mapped_file {
protected:
std::string _path;
char *_base, *_end;
size_t _length;
void map_(int fd) {
struct stat stat;
if(fstat(fd, &stat) < 0)
throw ErrorMMap(err::msg() << "Can't stat file '" << _path << "'" << err::no);
_length = stat.st_size;
_base = (char*)mmap(NULL, _length, PROT_READ, MAP_SHARED, fd, 0);
if(_base == MAP_FAILED) {
_base = 0;
throw ErrorMMap(err::msg() << "Can't mmap file '" << _path << "'" << err::no);
}
_end = _base + _length;
}
void map_(const char *filename) {
int fd = open(filename, O_RDONLY);
if(fd < 0)
throw ErrorMMap(err::msg() << "Can't open file '" << filename << "'" << err::no);
map_(fd);
close(fd);
}
public:
define_error_class(ErrorMMap);
mapped_file() : _path(), _base(0), _end(0), _length(0) { }
explicit mapped_file(const char *filename)
: _path(filename), _base(0), _end(0), _length(0)
{
map_(filename);
}
explicit mapped_file(int fd)
: _path(), _base(0), _end(0), _length()
{
map_(fd);
}
mapped_file(mapped_file&& rhs)
: _path(std::move(rhs._path)), _base(rhs._base), _end(rhs._end),
_length(rhs._length)
{
rhs._base = 0;
}
~mapped_file() {
unmap();
}
void map(const char* filename) {
unmap();
map_(filename);
}
void map(int fd) {
unmap();
map_(fd);
}
void unmap() {
if(!_base)
return;
munmap(_base, _length);
_path.clear();
_base = 0;
_length = 0;
}
mapped_file& operator=(mapped_file&& rhs) {
_path = std::move(rhs._path);
_base = rhs._base;
rhs._base = 0;
_end = rhs._end;
_length = rhs._length;
return *this;
}
void swap(mapped_file& rhs) {
std::swap(_path, rhs._path);
std::swap(_base, rhs._base);
std::swap(_end, rhs._end);
std::swap(_length, rhs._length);
}
char *base() const { return _base; }
char *end() const { return _end; }
size_t length() const { return _length; }
std::string path() const { return _path; }
// No error checking here. Should I throw something?
const mapped_file & will_need() const {
madvise(_base, _length, MADV_WILLNEED);
return *this;
}
const mapped_file & sequential() const {
madvise(_base, _length, MADV_SEQUENTIAL);
return *this;
}
const mapped_file & random() const {
madvise(_base, _length, MADV_RANDOM);
return *this;
}
const mapped_file & lock() const {
if(mlock(_base, _length) < 0)
throw ErrorMMap(err::msg() << "Can't lock map in memory" << err::no);
return *this;
}
char load() const {
const long sz = sysconf(_SC_PAGESIZE);
// Do not optimize. Side effect is that every page is accessed and
// should now be in cache.
volatile char unused = 0;
for(const char *w = _base; w < _base + _length; w += sz)
unused ^= *w;
return unused;
}
};
inline void swap(mapped_file& a, mapped_file& b) { a.swap(b); }
// class mapped_files_t : public std::vector<mapped_file> {
// public:
// mapped_files_t(int nb_files, char *argv[]) {
// for(int j = 0; j < nb_files; j++)
// push_back(mapped_file(argv[j]));
// }
// mapped_files_t(int nb_files, char *argv[], bool sequential) {
// for(int j = 0; j < nb_files; j++) {
// push_back(mapped_file(argv[j]));
// if(sequential)
// end()->sequential();
// }
// }
// };
// // File mapped on demand.
// class lazy_mapped_file_t : public mapped_file {
// std::string _path;
// volatile bool done;
// volatile long used_counter;
// public:
// explicit lazy_mapped_file_t(const char *path) :
// mapped_file((char *)0, (size_t)0),
// _path(path), done(false), used_counter(0) {}
// void map() {
// used_counter = 1;
// done = false;
// mapped_file::map(_path.c_str());
// }
// void unmap() {
// done = true;
// dec();
// }
// void inc() {
// atomic::gcc::fetch_add(&used_counter, (long)1);
// }
// void dec() {
// long val = atomic::gcc::add_fetch(&used_counter, (long)-1);
// if(done && val == 0)
// mapped_file::unmap();
// }
// };
// class lazy_mapped_files_t : public std::vector<lazy_mapped_file_t> {
// public:
// lazy_mapped_files_t(int nb_files, char *argv[]) {
// for(int j = 0; j < nb_files; j++)
// push_back(lazy_mapped_file_t(argv[j]));
// }
// lazy_mapped_files_t(int nb_files, char *argv[], bool sequential) {
// for(int j = 0; j < nb_files; j++) {
// push_back(lazy_mapped_file_t(argv[j]));
// if(sequential)
// end()->sequential();
// }
// }
// };
}
#endif
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