aria2/src/base32.cc

100 lines
2.7 KiB
C++

/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2009 Tatsuhiro Tsujikawa
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "base32.h"
#include "util.h"
namespace aria2 {
namespace base32 {
namespace {
const char B32TABLE[] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', '2', '3', '4', '5', '6', '7'
};
} // namespace
std::string encode(const std::string& src)
{
std::string ret;
size_t count = 0;
uint64_t buf = 0;
for(const auto& ch: src) {
buf <<= 8;
buf += ch & 0xffu;
++count;
if(count == 5) {
char temp[8];
for(size_t j = 0; j < 8; ++j) {
temp[7-j] = B32TABLE[buf&0x1fu];
buf >>= 5;
}
ret.append(&temp[0], &temp[8]);
count = 0;
buf = 0;
}
}
size_t r = 0;
if(count == 1) {
buf <<= 2;
r = 2;
} else if(count == 2) {
buf <<= 4;
r = 4;
} else if(count == 3) {
buf <<= 1;
r = 5;
} else if(count == 4) {
buf <<= 3;
r = 7;
}
char temp[7];
for(size_t j = 0; j < r; ++j) {
temp[r-1-j] = B32TABLE[buf&0x1fu];
buf >>= 5;
}
ret.append(&temp[0], &temp[r]);
if(r) {
ret.append(8-r, '=');
}
return ret;
}
} // namespace base32
} // namespace aria2