grive2/libgrive/src/util/Crypt.cc

78 lines
1.9 KiB
C++

/*
grive: an GPL program to sync a local directory with Google Drive
Copyright (C) 2012 Wan Wai Ho
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 version 2
of the License.
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.
*/
#include "Crypt.hh"
#include "StdioFile.hh"
#include "Exception.hh"
#include <iomanip>
#include <sstream>
// dependent libraries
#include <gcrypt.h>
#include <boost/throw_exception.hpp>
namespace gr { namespace crypt {
const std::size_t read_size = 8 * 1024 ;
std::string MD5( const fs::path& file )
{
try
{
StdioFile sfile( file ) ;
return MD5( sfile ) ;
}
catch ( StdioFile::Error& )
{
return "" ;
}
}
std::string MD5( StdioFile& file )
{
char buf[read_size] ;
gcry_md_hd_t hd ;
gcry_error_t err = gcry_md_open( &hd, GCRY_MD_MD5, GCRY_MD_FLAG_HMAC ) ;
if ( err != GPG_ERR_NO_ERROR )
{
BOOST_THROW_EXCEPTION( Exception() << expt::ErrMsg( gcry_strerror(err) ) ) ;
}
std::size_t count = 0 ;
while ( (count = file.Read( buf, sizeof(buf) )) > 0 )
gcry_md_write( hd, buf, count ) ;
gcry_md_final(hd) ;
unsigned char *md5 = gcry_md_read( hd, GCRY_MD_MD5 ) ;
// format the MD5 string
std::ostringstream ss ;
for ( unsigned int i = 0 ; i < gcry_md_get_algo_dlen(GCRY_MD_MD5) ; i++ )
ss << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(md5[i]) ;
gcry_md_close( hd ) ;
return ss.str() ;
}
} } // end of namespaces