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datastore.cc
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datastore.cc
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// Percy++ Copyright 2007,2012,2013 Ian Goldberg <iang@cs.uwaterloo.ca>,
// Casey Devet <cjdevet@cs.uwaterloo.ca>,
// Paul Hendry <pshdenry@uwaterloo.ca>,
// Ryan Henry <rhenry@cs.uwaterloo.ca>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of version 2 of the GNU General Public License as
// published by the Free Software Foundation.
//
// 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.
//
// There is a copy of the GNU General Public License in the COPYING file
// packaged with this plugin; if you cannot find it, write to the Free
// Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
// 02110-1301 USA
#include <fstream>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
#include "datastore.h"
#include "percyio.h"
#define FILENAME_SIZE 120
// You have to define even pure virtual destructors in C++. You just do.
DataStore::~DataStore() {}
MemoryDataStore::MemoryDataStore (unsigned char * database, const PercyParams ¶ms,
bool tau_independent) :
database(database)
{
bytes_per_word = tau_independent ? params.modulus_bytes()
: params.bytes_per_word();
words_per_block = params.words_per_block();
num_blocks = params.num_blocks();
/*
std::cerr << "bytes_per_word = " << bytes_per_word << "\n";
std::cerr << "words_per_block = " << words_per_block << "\n";
std::cerr << "num_blocks = " << num_blocks << "\n";
*/
}
MemoryDataStore::~MemoryDataStore () {}
// Retrieve the cth word of the jth block of the database as a ZZ.
// Both c and j are 0-based.
ZZ MemoryDataStore::get_word(dbsize_t c, dbsize_t j)
{
ZZ ret;
ZZFromBytes(ret, database +
(j*words_per_block+c)*(bytes_per_word), bytes_per_word);
return ret;
}
FileDataStore::FileDataStore(const char *filename, const PercyParams ¶ms,
bool tau_independent) :
MemoryDataStore(0, params)
{
offset = 0;
if (tau_independent) {
// Process the PIRD header
ifstream dbhead(filename);
// We'll turn these into exceptions later
char headbuf[6];
dbhead.read(headbuf, 6);
if (memcmp(headbuf, "PIRD\x01\x00", 6)) {
std::cerr << "Split database not in PIRD format.\n";
exit(1);
}
ZZ dbmodulus;
percy_read_ZZ(dbhead, dbmodulus);
if (!params.modulus_match(dbmodulus)) {
std::cerr << "Incorrect modulus for split database.\n";
exit(1);
}
offset = dbhead.tellg();
dbhead.close();
}
// Open the file so we can mmap it
dbfd = open(filename, O_RDONLY);
if (dbfd < 0) {
fprintf(stderr, "Could not open database %s\n", filename);
exit(1);
}
totbytes = bytes_per_word * words_per_block * num_blocks;
struct stat st;
fstat(dbfd, &st);
/*
std::cerr << "database = " << filename << "\n";
std::cerr << "st.st_size = " << st.st_size << "\n";
std::cerr << "totbytes = " << totbytes << "\n";
std::cerr << "offset = " << offset << "\n";
*/
if (st.st_size < (off_t)totbytes+offset) {
fprintf(stderr, "Database too small!\n");
exit(1);
}
mapptr = (unsigned char *)MMAP(NULL, totbytes+offset, PROT_READ,
MAP_SHARED, dbfd, 0);
if (mapptr == MAP_FAILED) {
perror("mmap");
exit(1);
}
database = mapptr + offset;
}
FileDataStore::~FileDataStore()
{
munmap(mapptr, totbytes + offset);
close(dbfd);
}